WO2010101110A1 - Moisture adsorbent, sheet-like material for dehumidification, and filter material for dehumidification - Google Patents

Abstract

Disclosed are: a moisture adsorbent which can adsorb a large amount of moisture in all of a high-moisture atmosphere, a moderate-moisture atmosphere and a low-moisture atmosphere, has a structure that cannot be disrupted by a moisture-absorbable salt, and can be regenerated at a low temperature; and a sheet-like material for dehumidification and a filter material for dehumidification, each of which comprises the moisture adsorbent. Specifically disclosed are: a moisture adsorbent comprising an amorphous aluminum silicate having an Si/Al ratio of 0.7 to 1 and also having peaks at around -78 ppm and -87 ppm in ²⁹Si solid NMR spectra and a moisture-absorbable salt; and a sheet-like material for dehumidification and a filter material for dehumidification, each of which comprises the moisture adsorbent.

Description

Moisture absorbent, dehumidified sheet and dehumidifying filter material

The present invention relates to a moisture adsorbent, a sheet material for dehumidification, and a filter material for dehumidification. The present invention also relates to a moisture absorbing / releasing sheet, a moisture absorbing / releasing structure, and a method for producing them. The present invention further relates to an adsorption sheet and a coating liquid.

Desiccant air conditioners are air conditioners that produce low-humidity air using a moisture adsorbent called a desiccant. By supplying low-humidity air, comfort can be sufficiently obtained even if the temperature is not so low. This desiccant air conditioner has an air supply fan for introducing air from the outside into the room, a dehumidification rotor for dehumidification by adsorbing moisture in the supply air, and a cooling for cooling the dehumidified air. A regenerator, a heater for regenerating the dehumidification rotor by removing moisture adsorbed on the dehumidification rotor, and a regeneration fan for exhausting indoor air to the outside. The dehumidification rotor is obtained by processing a dehumidification filter material containing a moisture adsorbent into a rotor. By rotating the dehumidifying rotor, an adsorption zone that adsorbs moisture of the processing air and a regeneration zone that removes the adsorbed moisture at a high temperature are sequentially passed.

The moisture adsorbent of the dehumidifying filter material is required to have a large moisture adsorption amount. In addition, since the desiccant air conditioner requires heating energy for desorbing adsorbed moisture from the moisture adsorbent in the regeneration zone, the energy efficiency of the entire air conditioner is not always satisfactory. Therefore, a moisture adsorbent that can be regenerated at a low temperature is required in order to reduce the regeneration temperature, which was generally high (80 ° C. or higher), to a low temperature (40 ° C. to 80 ° C.).

Furthermore, in the past, there was a need for low-humidity air in a high-humidity atmosphere such as in summer or during the rainy season. However, in recent years, in the spring and autumn, clean rooms, commercial facilities, etc., lower humidity in a medium-low humidity environment. Is required. Therefore, in the adsorption zone (temperature 15 to 40 ° C), all of high humidity atmosphere (relative humidity 90% or more), medium humidity atmosphere (relative humidity 50% or more and less than 90%), low humidity atmosphere (relative humidity 50% or less). There is a need for moisture adsorbents that have a large amount of moisture adsorption.

Under such circumstances, as a substance that has high adsorption performance in a medium-humidity atmosphere and can be suitably used as an active ingredient of an adsorbent, a Si / Al ratio of 0.7 to 1 and a ²⁹ Si solid Techniques for synthesizing amorphous aluminum silicates having peaks in the vicinity of −78 ppm and −87 ppm in the NMR spectrum have been proposed (Patent Document 1 and Non-Patent Document 1).

Also, for the purpose of improving the amount of moisture adsorption, a technique for supporting a hygroscopic salt such as lithium chloride, magnesium chloride, calcium chloride on a porous moisture adsorbent has been proposed (see, for example, Patent Documents 2 to 5).

Patent Document 2 describes a technique in which a hygroscopic salt is contained in silica gel, which is the most common porous moisture adsorbent. However, silica gel having a pore diameter of 1 to 3 nm and a specific surface area of more than 900 m ² / g does not readily release the moisture once adsorbed. Therefore, a regeneration temperature of 80 ° C. or higher is required, and even if a hygroscopic salt is contained. There was a problem that the regeneration temperature did not fall. Silica gel with a specific surface area of 700 m ² / g or more and a pore diameter of 5 to 7 nm has a low regeneration temperature and excellent moisture adsorption in a high-humidity atmosphere, but has a low moisture adsorption amount in a medium and low-humidity atmosphere. However, even if a hygroscopic salt is contained, the moisture adsorption amount is not improved to a level necessary for use in a desiccant air conditioner. Silica gel has a problem of structural deterioration. Even when silica gel is used alone, it has a problem of falling off from the dehumidifying filter material or dehumidifying performance. There was a problem that the structural deterioration further progressed.

Patent Document 3 describes a technique of attaching a hygroscopic salt to mesoporous silica synthesized with an organic template. Mesoporous silica has mesopores having a sharp pore size distribution, and moisture is spontaneously stored in the mesopores by surface tension, and thus has a large moisture adsorption amount. However, the mesopores have a pore diameter of 1 to 10 nm, and the water adsorption amount in the medium and low humidity atmosphere is large, but the water adsorption amount in the high humidity atmosphere is small. Further, when a hygroscopic salt is added to the mesoporous silica, there is a serious problem that the structure of the mesoporous silica is destroyed and the moisture adsorption amount is lowered.

In Patent Document 4, a hygroscopic salt is supported on a zeolite having a sharp pore size distribution, but the zeolite has a very small average pore size of about 1 nm, and has a large amount of moisture adsorption in a medium and low humidity atmosphere. There was a problem that the amount of moisture adsorption in a high humidity atmosphere was small. Moreover, since the pore diameter is small, there is a problem that moisture is difficult to desorb, and a regeneration temperature of 100 ° C. or higher is necessary. Even when a hygroscopic salt is supported on zeolite, the amount of water adsorption increases little, and the hygroscopic salt in the pores inhibits desorption of water.

In Patent Document 5, cristobalite, which is a natural stone, carries a hygroscopic salt. However, cristobalite has a high regeneration temperature, and the hygroscopic salt destroys the structure of cristobalite.

As described above, in the known porous water adsorbents carrying hygroscopic salts, not only those that satisfy the moisture adsorption amount in all high, medium and low humidity atmospheres have been obtained, but also the moisture due to the hygroscopic salts. There was a problem that the structure of the adsorbent could not be broken and low temperature regeneration could not be performed. On the other hand, the amorphous aluminum silicate described in Patent Document 1 is used alone as a water adsorbent carrying a hygroscopic salt in order to exhibit excellent adsorption performance particularly in a medium-humidity atmosphere. It was not.

The desiccant air-conditioning system is attracting attention due to the increasing momentum to realize an energy-saving society. Conventional air conditioning (cooling and dehumidification) is based on the movement of heat using a refrigerant, and the refrigerant is compressed by a compressor of an outdoor unit and condensed by a condenser. Thereafter, the refrigerant is cooled by the expansion valve and sent to the indoor unit to cool the indoor air. By repeating this cycle, the room is cooled. In the case of dehumidification, air and moisture are separated by cooling to a temperature at which water vapor contained in the room air is condensed. In any process, much energy is consumed in the process of compressing the refrigerant or reheating the cooled air to obtain a comfortable temperature.
On the other hand, the desiccant air conditioning system is a very effective system for realizing an energy-saving society because moisture in the air is separated from the air by the hygroscopic agent, and energy consumption during compression and reheating is reduced. Attention has been paid.

In the desiccant air conditioning system, air is dehumidified by passing air through a dehumidification rotor carrying a hygroscopic agent on the surface of the flow path, and the hygroscopic agent adsorbs moisture. The dehumidifying rotor is constructed by incorporating a moisture absorbing / releasing structure having a moisture absorbent on its surface in a casing. The dehumidification rotor rotates in the desiccant air conditioning system to absorb and remove moisture from the air, and removes and discharges moisture from the moisture absorbent so that the moisture absorbent can be used again for moisture adsorption It passes through the zones sequentially and is repeatedly used to perform the dehumidifying function. As the hygroscopic agent, a porous inorganic material having fine pores such as silica gel and zeolite is used. As the porous inorganic material, titanium oxide and the like have been proposed mainly for the silicate compounds such as silica gel and zeolite (see, for example, Patent Documents 6 and 7).

As a method for producing a hygroscopic structure using these porous inorganic materials as a hygroscopic agent, (1) a method of kneading a hygroscopic agent with clay minerals, inorganic fibers, etc., and molding it into a honeycomb or the like with an extruder, (2) A method of impregnating a honeycomb-shaped structure processed with a porous material or the like into a slurry composition containing a hygroscopic agent, and supporting the hygroscopic agent on the surface of the structure, (3) paper In addition, a sheet containing a hygroscopic agent is impregnated or coated on a sheet such as a non-woven fabric so that the sheet has moisture absorbing / releasing performance, and then the sheet is processed into a honeycomb to form a moisture absorbing / releasing structure. And (4) a method in which a slurry composition comprising a hygroscopic agent, organic and / or inorganic fibers, a binder, and the like is formed into a sheet by a wet papermaking method, and the sheet is processed into a honeycomb to form a hygroscopic structure. (For example, see Patent Documents 8 to 11).

Among these methods, in the methods (2) to (3), the moisture absorbent is supported on the moisture absorbing / releasing structure or sheet by entanglement of inorganic / organic fibers, by inorganic / organic binder, etc. However, in any case, the porosity of the hygroscopic agent is lowered, and the hygroscopic performance is inferior to that of the hygroscopic agent alone. In addition, because the different compositions are bonded and supported, there is a problem that the bonded surface is weak and the hygroscopic agent gradually falls off during long-term use, resulting in a decrease in hygroscopic performance. is there.

Furthermore, in the past, there has been a demand for low-humidity air in a high-humidity atmosphere such as in summer and in the rainy season. It is requested to be. Therefore, in the adsorption zone (temperature 15 to 40 ° C.) in which the dehumidification rotor adsorbs moisture in the air (that is, dehumidifies), a high humidity atmosphere (relative humidity 90% or more) and a medium humidity atmosphere (relative humidity 50% or more 90%). %) And a low-humidity atmosphere (relative humidity of less than 50%) are all demanded.

As described above, as a porous inorganic material used as a hygroscopic agent, zeolite has many types and is used in various fields. In fact, there are many proposals for the production method using zeolite. However, zeolite has a problem that the average pore diameter is as small as 1 nm or less, and the amount of moisture absorption in a high and low humidity atmosphere is small, while the amount of moisture absorption in a medium and low humidity atmosphere is large.
Also, in the dehumidification rotor, it is necessary to desorb moisture that has been absorbed, and use it again in the adsorption zone.Therefore, warm air is introduced into the moisture absorption / desorption structure of the dehumidification rotor in the regeneration zone, and the adsorbed moisture is removed. It is necessary to desorb. However, zeolite has a problem that moisture is difficult to desorb because of its small pore diameter, and the desired moisture releasing property cannot be obtained unless hot air of 100 ° C. or higher is introduced into the regeneration zone. The advantage of the desiccant air conditioning system at the corner is lost. Further, in the regeneration zone, hot air is used for desorption of moisture, so there is a risk that the heat partially accumulates and the temperature rises locally and ignites. Therefore, a moisture absorbing / releasing agent or a nonflammable moisture absorbing / releasing structure capable of desorbing moisture at a lower temperature of hot air necessary for moisture desorption is desired.

Therefore, amorphous aluminum silicates described in Patent Document 1 and Non-Patent Document 1 have been proposed as hygroscopic agents that improve the disadvantages of this zeolite. However, although the moisture absorption / release characteristics of the amorphous aluminum silicate are very good, as described above, in the conventional method for manufacturing a moisture absorption / release structure, the aluminum silicate is removed during long-term use. It has been found that the moisture absorption / release performance deteriorates due to. Moreover, the technique which makes the moisture absorption / release performance as a moisture absorption / release structure as high as possible is desired from the viewpoint of reducing energy consumption as much as possible.

Furthermore, using the adsorption capacity and desorption capacity of the adsorbent, gas removal system such as organic gas (VOC), carbon monoxide, carbon dioxide, nitrogen oxide (NO _X ), heat exchange or heat transfer system, humidity control (Dehumidification or humidification) systems have been developed. Adsorption elements used in these various systems are provided with an adsorption layer containing an adsorbent and a binder on a sheet substrate such as paper, fabric, film, porous film, metal foil, and metal plate. It is composed of a suction sheet.

The adsorbing layer of the adsorbing sheet is manufactured by applying a coating liquid in which an adsorbent is dispersed in water as a medium together with a binder (see, for example, Patent Documents 12 to 14). As the adsorbent, porous materials such as silica gel, zeolite, activated alumina, activated carbon and the like are mainly used. In addition, when a water-soluble polymer is used as a binder, there is a problem in that when condensation occurs on the adsorption sheet in a high humidity atmosphere, the adsorbent is detached from the sheet base material together with the binder. Examples of the agent include (meth) acrylic resin, vinyl acetate resin, (meth) acrylic / styrene copolymer resin, ethylene / vinyl acetate copolymer resin, styrene / butadiene copolymer resin, styrene / acrylonitrile / (meth) acrylic acid. An emulsion composed of a water-insoluble polymer such as an alkyl ester copolymer resin or vinyl acetate / (meth) acrylic acid alkyl ester copolymer resin is used.

However, the adsorption characteristics of a porous material such as silica gel used as the adsorbent are not always satisfactory, and various adsorbents with more excellent adsorption characteristics have been proposed in recent years. For example, amorphous aluminum silicates described in Patent Document 1 and Non-Patent Document 1 are known as adsorbents having higher adsorption characteristics than silica gel and zeolite. In Patent Document 1 and Non-Patent Document 1, although an adsorbent using amorphous aluminum silicate is described, no application of this adsorbent to an adsorbing sheet has been studied. .

In order to apply this amorphous aluminum silicate to a sheet substrate, a water-insoluble polymer emulsion that is a binder used together with a porous material such as silica gel that is a conventional adsorbent is used. Then, gelation of the coating liquid, precipitation of the amorphous aluminum silicate or emulsion occurs, causing problems such as uneven adsorption layer, reduced coating amount, and inability to coat.

JP 2008-179533 A JP 2003-201113 A JP-A-11-114410 Japanese Patent Publication No. 7-49091 JP-A-60-241930 JP 2001-149735 A JP 2006-272329 A JP 58-109118 A Japanese Patent Laid-Open No. 05-023529 Japanese Patent Laid-Open No. 05-023584 Japanese Patent Application Laid-Open No. 60-062598 Japanese Patent Laid-Open No. 10-286460 JP 2002-095964 A Japanese Patent Laid-Open No. 2007-245025

"Inorganic porous material with excellent carbon dioxide adsorption performance and productivity", [online], December 4, 2008, National Institute of Advanced Industrial Science and Technology, [searched July 14, 2009] , Internet <http://www.aist.go.jp/aist_j/press_release/pr2008/pr20081204/pr20081204.html>

An object of the present invention is to provide a moisture adsorbent that can be regenerated at a low temperature without damaging the structure of the moisture adsorbent by the hygroscopic salt in a high, medium, and low humidity atmosphere, and a dehumidifying sheet using the same. The object is to provide a filter and a dehumidifying filter material.

Another object of the present invention is to provide a moisture absorbing / releasing sheet and a moisture absorbing / releasing structure using an amorphous aluminum silicate, without impairing the excellent moisture absorbing / releasing properties of the amorphous aluminum silicate. An object of the present invention is to provide a moisture absorbing / releasing sheet and a moisture absorbing / releasing structure which have high moisture absorbing / releasing performance and are nonflammable with little deterioration in moisture absorbing / releasing performance due to long-term use.

Still another object of the present invention is to provide an adsorption sheet exhibiting high adsorption characteristics in an adsorption sheet in which an adsorption layer containing at least an adsorbent and a binder is provided on a sheet substrate. It is. Moreover, it is suppressing the gelatinization of a coating liquid etc. and improving the manufacture stability of the sheet | seat for adsorption | suction.

As a result of repeated studies to solve the above problems, the present inventors have found that the above problems have a Si / Al ratio of 0.7 to 1 and peaks at around −78 ppm and −87 ppm in a ²⁹ Si solid state NMR spectrum. A water adsorbent comprising an amorphous aluminum silicate having a moisture content and a hygroscopic salt, a dehumidifying sheet containing the water adsorbent, and the dehumidifying sheet It has been found that the problem can be solved by a filter material for dehumidification.

Further, the moisture absorbing / releasing sheet and the moisture absorbing / releasing structure containing the amorphous aluminum silicate and the water-soluble silicate further contain the amorphous aluminum silicate and a binder. It has been found that the above problem can be solved by an adsorption sheet having an adsorption layer provided on a sheet substrate.

That is, the present invention for solving the above-described problems is as follows.
(1) An amorphous aluminum silicate having a Si / Al ratio of 0.7 to 1 and having peaks in the vicinity of -78 ppm and -87 ppm in a ²⁹ Si solid state NMR spectrum and a hygroscopic salt A moisture adsorbent characterized by that.
(2) The above (1), wherein the hygroscopic salt is at least one selected from the group consisting of metal halide salts, metal sulfates, metal acetates, amine salts, phosphate compounds, guanidine salts, and metal hydroxides. ) The moisture adsorbent described.
(3) The moisture adsorbent according to (1) above, wherein the hygroscopic salt is a metal halide salt or a guanidine salt (4) The moisture according to any one of (1) to (3) above A sheet for dehumidification comprising an adsorbent.
(5) A filter material for dehumidification comprising the water adsorbent according to any one of (1) to (3) above.

(6) An amorphous aluminum silicate having a Si / Al ratio of 0.7 to 1.0 and having peaks in the vicinity of −78 ppm and −87 ppm and a water-soluble silicate in a ²⁹ Si solid state NMR spectrum. A moisture-absorbing / releasing sheet characterized by comprising.
(7) The water-soluble silicate is at least one selected from the group consisting of sodium silicate, disodium silicate, disodium silicate pentahydrate, sodium silicate nonahydrate and potassium silicate. The moisture-absorbing / releasing sheet according to the above (6).
(8) The moisture-absorbing / releasing sheet according to (6) or (7), wherein the water-soluble silicate is contained in an amount of 1 to 50% by mass relative to the total of the amorphous aluminum silicate and the water-soluble silicate. .
(9) The hygroscopic sheet according to any one of (6) to (8), further supporting a hygroscopic salt.
(10) An amorphous aluminum silicate having a Si / Al ratio of 0.7 to 1.0 and having peaks in the vicinity of −78 ppm and −87 ppm and a water-soluble silicate in a ²⁹ Si solid state NMR spectrum. A method for producing a moisture absorbing / releasing sheet, comprising a step of supporting the sheet and a step of firing the sheet at a temperature of 920 ° C. or lower.
(11) An amorphous aluminum silicate and a water-soluble silicate having a Si / Al ratio of 0.7 to 1.0 and having peaks near −78 ppm and −87 ppm in a ²⁹ Si solid state NMR spectrum. A moisture-absorbing / releasing structure characterized in that a composition containing it is supported on a honeycomb-like structure.
(12) The water-soluble silicate is at least one selected from the group consisting of sodium silicate, disodium silicate, disodium silicate pentahydrate, sodium silicate nonahydrate and potassium silicate. The moisture absorbing / releasing structure according to (11) above.
(13) The moisture-absorbing / releasing property according to (11) or (12), wherein the water-soluble silicate is contained in an amount of 1 to 50% by mass based on the total of the amorphous aluminum silicate and the water-soluble silicate. Structure.
(14) The hygroscopic structure according to any one of (11) to (13), further supporting a hygroscopic salt.
(15) An amorphous aluminum silicate having a Si / Al ratio of 0.7 to 1.0 and having peaks in the vicinity of −78 ppm and −87 ppm and a water-soluble silicate in a ²⁹ Si solid state NMR spectrum. A method for producing a moisture absorbing / releasing structure, comprising a step of supporting a composition containing the honeycomb structure on a honeycomb structure and a step of firing the honeycomb structure at a temperature of 920 ° C. or lower.

(16) In the adsorption sheet in which an adsorption layer containing at least an adsorbent and a binder is provided on the sheet base material, the adsorbent has an Si / Al ratio of 0.7 to 1.0, A sheet for adsorption, which is an amorphous aluminum silicate having peaks in the vicinity of −78 ppm and in the vicinity of −87 ppm in a ²⁹ Si solid state NMR spectrum.
(17) The adsorption sheet according to the above (16), wherein the binder is an organic solvent-soluble polymer.
(18) The adsorption sheet according to (17), wherein the organic solvent-soluble polymer is a vinylidene fluoride-based polymer.
(19) The adsorption sheet according to the above (17), wherein the organic solvent-soluble polymer is N-alkoxyalkylated polyamide.
(20) The adsorption sheet according to any one of (16) to (19), wherein the mass ratio of the adsorbent and the binder in the adsorption layer is 93/7 to 70/30.
(21) A coating liquid comprising at least an adsorbent, a binder, and a medium, wherein the adsorbent has a Si / Al ratio of 0.7 to 1.0 and a ²⁹ Si solid state NMR spectrum. A coating liquid which is an amorphous aluminum silicate having peaks at around -78 ppm and around -87 ppm, the medium is an organic solvent, and the binder is an organic solvent-soluble polymer.
(22) The coating liquid according to (21), wherein the organic solvent-soluble polymer is a vinylidene fluoride-based polymer.
(23) The coating solution according to (21) above, wherein the organic solvent-soluble polymer is N-alkoxyalkylated polyamide.
(24) An adsorbing sheet having an adsorbing layer formed by applying the coating liquid according to any one of (21) to (23) to a sheet substrate.

The moisture adsorbent of the present invention has an amorphous aluminum silicate having a Si / Al ratio of 0.7 to 1 and peaks in the vicinity of −78 ppm and −87 ppm in a ²⁹ Si solid state NMR spectrum (hereinafter referred to as “non- Crystalline water adsorbent ”and a hygroscopic salt. The amorphous moisture adsorbent is a composite particle (hereinafter, referred to as “single particle”) and an amorphous aluminum silicate bound together with a low crystalline clay. "Composite particles"). ^{In the 29} Si solid state NMR spectrum, the amorphous aluminum silicate single particles have peaks near −78 ppm, and the composite particles have peaks near −78 ppm and −87 ppm.
Since composite particles have hydroxyl groups derived from aluminum hydroxide on the surface of each particle, the composite particles exhibit high hydrophilicity and easily adhere to moisture. Further, the composite particles can adsorb moisture even in the gap between the amorphous aluminum silicate and the low crystalline clay. Further, each particle forms an aggregate structure, and this aggregate structure forms a pseudo mesopore. Due to the hydroxyl group on the particle surface, the pseudo mesopores are highly hydrophilic and can adsorb moisture.
In this way, the amorphous moisture adsorbent adsorbs moisture at three sites with different pore sizes: the particle surface, the gap between the composite particles, and the pseudo mesopores of the aggregated structure. Large amount of moisture adsorption. Further, since the pore diameter of the pseudo mesopores extends to 2 to 20 nm, the moisture desorption rate is high and low temperature regeneration is possible.

In the moisture adsorbent (1) of the present invention comprising the amorphous moisture adsorbent and the hygroscopic salt, the moisture retention performance is greatly improved by the penetration of the hygroscopic salt into the gaps between the composite particles. In addition, the moisture adsorption amount in a high humidity atmosphere is improved. Further, since the hygroscopic salt serves as an auxiliary tank of water inside the pseudo mesopores present in the aggregated structure, the amount of moisture adsorbed in the medium and low humidity atmosphere is improved. Therefore, the amount of moisture adsorption is improved in all of the high, medium, and low humidity atmospheres as compared with the case of the amorphous moisture adsorbent alone.
Such an effect is specific to the amorphous water adsorbent having composite particles and pseudo mesopores. And the pore size distribution of the amorphous moisture adsorbent is wide, and the pores are not clogged with hygroscopic salts like zeolite, so the moisture desorption rate is not extremely slow, Playback is also possible.

In addition, since the hydroxyl groups present on most of the particle surface of the amorphous water adsorbent are derived from aluminum hydroxide, even if hygroscopic salts adhere, silica-based materials such as silica gel, mesoporous silica, cristobalite, etc. The structure is not destroyed.

Thus, the moisture adsorbent (1) of the present invention has a large moisture adsorption amount in all high, medium and low humidity atmospheres, can be regenerated at low temperature, and has no structural deterioration. Therefore, the sheet for dehumidification (4) and the filter material for dehumidification (5) containing the moisture adsorbent of the present invention also have a high moisture adsorption amount in all high, medium and low humidity atmospheres, and can be regenerated at low temperature and are stable. Dehumidifying performance can be obtained.

The hygroscopic sheet (6) and the hygroscopic structure (11) of the present invention are obtained by combining the amorphous aluminum silicate (hereinafter also referred to as “amorphous hygroscopic agent”) with a water-soluble silicate. By supporting it on a sheet or honeycomb structure, the heat absorption strength is maintained while maintaining the excellent moisture absorption and desorption characteristics of the amorphous absorbent due to the affinity between the amorphous absorbent and the water-soluble silicate. In addition, the deterioration of moisture absorption / release characteristics can be reduced even when used for a long period of time. In addition, by further supporting the hygroscopic salt on the hygroscopic sheet or the hygroscopic structure, the moisture absorption capacity of moisture can be increased, and the hygroscopic property, in particular, the moisture absorption rate can be increased.

The hygroscopic sheet (6) and the hygroscopic structure (11) of the present invention are combined with an amorphous hygroscopic agent and a water-soluble silicate and supported on a sheet or a honeycomb structure, By firing the sheet or honeycomb-like structure at a temperature of 920 ° C. or lower, it is possible to reduce deterioration of moisture absorption / release characteristics due to powder loss of the amorphous moisture absorbent due to long-term use. In addition, the moisture absorbing / releasing sheet (6) and the moisture absorbing / releasing structure (11) of the present invention are burned at a temperature of 920 ° C. or lower, so that the burned product burns and does not contain the burned product. It is nonflammable.

According to the present invention (16), it is possible to provide an adsorbing sheet that suppresses the adsorbent from falling off the sheet base material and has high adsorbing characteristics. Moreover, the coating liquid (21) of the present invention can suppress gelation and the like, and can enhance the production stability during the production of the adsorption sheet.

It is a section schematic diagram of a moisture adsorption / desorption test device.

The amorphous moisture adsorbent according to the present invention is water assembled with a number of Si—O—Al bonds, with silicon (Si), aluminum (Al), oxygen (O) and hydrogen (H) as main constituent elements. It is a Japanese aluminum silicate, and a peak around −78 ppm is observed in the ²⁹ Si solid state NMR spectrum. In the ²⁹ Si solid state NMR spectrum, the peak around −87 ppm indicates that the SiO ₄ tetrahedron contains a state containing at least one Si—O—Si bond. The amorphous moisture adsorbent according to the present invention requires peaks at around −78 ppm and around −87 ppm in the ²⁹ Si solid state NMR spectrum, but may have other peaks.

The amorphous moisture adsorbent is composed of single particles and composite particles. Single particles are aggregates of amorphous aluminum silicate, and composite particles are formed by binding single particles of amorphous aluminum silicate with low crystalline clay. Since composite particles have hydroxyl groups derived from aluminum hydroxide on the surface of each particle, they exhibit high hydrophilicity (surface activity) and easily adsorb moisture and various gases (hereinafter referred to as “moisture”). The composite particles can adsorb moisture and the like even in the gap between the amorphous aluminum silicate and the low crystalline clay. Further, each particle forms an aggregate structure, and this aggregate structure forms a pseudo mesopore. Due to the hydroxyl groups on the particle surface, the pseudo mesopores are hydrophilic inside, exhibit high surface activity, and can efficiently adsorb moisture and the like. As described above, the amorphous moisture adsorbent is a material that adsorbs moisture and the like by a mechanism based on three sites having different pore diameters such as particle surfaces, composite particle gaps, and pseudo mesopores of the aggregate structure. In addition, in the entire region of the high, medium, and low humidity atmosphere, each mechanism complements each other and the effect that the amount of adsorption of moisture and the like is large can be obtained. In addition, since the pseudo mesopore diameter extends to 2 to 20 nm, the adsorption / desorption rate of moisture and the like is high, and the effect of enabling low-temperature regeneration is also obtained.

A single particle of the amorphous water adsorbent is an aggregate of amorphous aluminum silicate, and the composite particle is formed by binding single particles of amorphous aluminum silicate and low crystalline clay. Aggregated structure. When the powder X-ray diffraction measurement of the amorphous moisture adsorbent is performed, broad peaks are observed around 2θ = 27 ° and around 40 ° in the amorphous moisture adsorbent composed only of single particles.

The primary particle size of single particles is 2 to 5 nm, and the particle size of composite particles is 2 to 40 nm. Further, single particles and composite particles or low crystalline clay form an aggregate structure, and the particle size of the aggregate structure is 0.1 to 100 μm. The pore diameter of the pseudo mesopores present in the aggregated structure is 2 to 20 nm. The primary particle size of the single particles is measured with a transmission electron microscope, the particle size of the composite particles is measured with a transmission electron microscope or a scanning electron microscope, and the particle size of the aggregate structure and pseudo mesopores are measured. The pore diameter was measured with a scanning electron microscope.

Amorphous moisture adsorbent can be obtained artificially by heating and aging after mixing a solution consisting of inorganic silicon compound solution and inorganic aluminum compound solution, polymerizing and desalting silicon and aluminum. is there.

In the present invention, for the preparation of the amorphous water adsorbent, a silicon compound as a silicon source and an aluminum compound as an aluminum source are usually used as raw materials. The silicon compound used as the silicon source may be monosilicic acid. Specifically, for example, sodium orthosilicate, sodium metasilicate, amorphous colloidal silicon dioxide (aerosil, etc.), water glass, etc. are suitable. As mentioned. Specific examples of the aluminum compound used as the aluminum source include aluminum chloride, aluminum nitrate, aluminum sulfate, and sodium aluminate. These silicon sources and aluminum sources are not limited to the above compounds, and various silicon compounds and aluminum compounds can be used as appropriate as long as they are equivalent to the above compounds.

These raw materials are dissolved in an appropriate aqueous solution to prepare a solution having a predetermined concentration. In order to show an excellent moisture adsorption amount in a high, medium and low humidity atmosphere, it is necessary to mix so that the silicon / aluminum ratio (Si / Al) ratio is 0.7-1. In the present invention, the Si / Al ratio is on a molar basis. The concentration of the silicon compound in the solution is 1 to 2000 mmol / L, and the concentration of the aluminum compound solution is 1 to 2000 mmol / L. As a suitable concentration, the concentration of the silicon compound is 1 to 700 mmol / L, and the concentration of the aluminum compound is 1 to 1000 mmol / L. Based on these ratios and concentrations, a silicon compound solution is mixed with an aluminum compound solution, adjusted to pH 6-9 using acid or alkali, and after forming a precursor, it is subjected to centrifugation, filtration, membrane separation, etc. Remove the coexisting ions in the solution and recover the precursor. Next, the solid content produced by dispersing the precursor in a weakly acidic to weakly alkaline aqueous solution and synthesizing it with heat has amorphous aluminum silicic acid having peaks in the vicinity of −78 ppm and −87 ppm in the ²⁹ Si solid state NMR spectrum. Salt.

Specific examples of the hygroscopic salt used in the moisture adsorbent (1) in the present invention include metal halide salts such as lithium chloride, calcium chloride, and magnesium chloride, sodium sulfate, calcium sulfate, magnesium sulfate, and zinc sulfate. Metal sulfates such as potassium acetate, metal acetates such as potassium acetate, amine salts such as dimethylamine hydrochloride, phosphate compounds such as orthophosphoric acid, guanidine salts such as guanidine hydrochloride, guanidine phosphate, guanidine sulfamate, potassium hydroxide, hydroxide Examples thereof include metal hydroxides such as sodium and magnesium hydroxide. Among these, metal halide salts and guanidine salts are preferable, and the water adsorption amount of the water adsorbent can be increased.

By the way, in general, hygroscopic salt is a material that deprives moisture from the air and causes deliquescent phenomenon, and drops from the dehumidifying sheet or dehumidifying filter material or causes rust. Is known to occur. However, when an amorphous moisture adsorbent and a hygroscopic salt are used together as in the present invention, a hydroxyl group derived from aluminum hydroxide is present in pores such as gaps in the composite particles and pseudo mesopores in the aggregated structure. Since the hygroscopic salt exists and adheres thereto, the hygroscopic salt is efficiently held by the hydroxyl group, and dropping off is suppressed.

The content of the hygroscopic salt is preferably 1 part by mass or more and less than 100 parts by mass, and more preferably 2 parts by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the amorphous water adsorbent. If it is less than 1 part by mass, the effect of increasing the amount of moisture adsorption may be insufficient, and if it is 100 parts by mass or more, moisture may be difficult to desorb.

The water adsorbent of the present invention can be produced by mixing an amorphous water adsorbent and an aqueous solution of a hygroscopic salt and drying.

The sheet material (4) for dehumidification of the present invention can be produced by the following method.
(1) A method of supporting a hygroscopic salt after a web containing an amorphous moisture adsorbent and a fibrous material is produced by a wet papermaking method or a dry method,
(2) A method in which an amorphous moisture adsorbent and a hygroscopic salt are supported on a sheet-like base material simultaneously or separately by a coating method.

The dehumidifying filter material (5) of the present invention can be produced by the following method. Method (I) is suitable for mass production.
(I) A method of filtering the sheet-like material of the present invention comprising the amorphous water adsorbent and the hygroscopic salt produced by the method of (1) or (2) above,
(II) A method of supporting a hygroscopic salt by a coating method after filtering a web containing only an amorphous water adsorbent,
(III) A method in which an amorphous water adsorbent and a hygroscopic salt are simultaneously or separately supported by a coating method after filtering a sheet-like base material.

A web containing an amorphous moisture adsorbent is produced by a wet papermaking method or a dry method. As the dry method, a card method, an airlaid method, or the like can be used. The wet papermaking method is a method in which a diluted material is dispersed in water at a low concentration and the paper is made up. This method is inexpensive, highly uniform, and capable of mass production. Specifically, a slurry is mainly composed of an amorphous moisture adsorbent and a fibrous material, and a filler, a dispersant, a thickener, an antifoaming agent, a paper strength enhancer, a sizing agent, a flocculant, A colorant, a fixing agent, and the like are added as appropriate, and wet papermaking is performed with a paper machine. As the paper machine, a circular paper machine, a long paper machine, a short paper machine, an inclined paper machine, a combination paper machine in which the same or different kinds of paper machines are combined, and the like can be used. The web can be obtained by drying the wet paper after paper making using an air dryer, cylinder dryer, suction drum dryer, infrared dryer or the like.

Fibrous materials include olefin resins, polyester resins, polyvinyl acetate resins, ethylene vinyl acetate copolymer resins, polyamide resins, acrylic resins, polyvinyl chloride resins, polyvinylidene chloride resins, polyvinyl ether resins, polyvinyl ketone resins. Thermosetting synthetic resins such as polyether resin, polyvinyl alcohol resin, diene resin, and polyurethane resin, phenol resin, melamine resin, furan resin, urea resin, aniline resin, unsaturated polyester resin, alkyd resin, etc. It is a fiber made of a functional resin. In addition, plant fibers such as wood pulp, cocoon, cocoon, cocoon, kenaf, bamboo, linter, bagasse, esparto, sugarcane, etc., or those made finer can be used, and rayon fibers that are cellulose regenerated fibers, Semi-synthetic fibers such as acetate, fluorine resin fibers such as polytetrafluoroethylene (PTFE), silicone resin fibers, metal fibers such as stainless steel and nickel wool, carbon fibers, ceramic fibers, and glass fibers can also be used.

In the wet papermaking method, a flocculant can be added to stabilize the agglomerated structure composed of the amorphous water adsorbent and the fibrous material. As the flocculant, metal hydroxides such as zinc hydroxide, aluminum hydroxide and magnesium hydroxide, metal oxides or metal silicates such as alumina, silica, aluminum silicate and magnesium silicate, these metal oxides or metal silicates Water-containing products, aluminum sulfate, polyaluminum chloride, anion- or cation-modified polyacrylamide, water-soluble polymers such as polyethylene oxide polymers, acrylic acid or methacrylic acid-containing copolymers, alginic acid or polyvinyl phosphoric acid and their alkaline salts And alkylamines such as ammonia, diethylamine and ethylenediamine, alkanolamines such as ethanolamine, pyridine, morpholine, and acryloylmorpholine-containing polymer. In particular, among the anionic or cation-modified water-soluble polymer flocculants, amphoteric flocculants having both cation units and anion units in the polymer can exhibit an excellent aggregation effect.

In the method (2) and method (III), when the amorphous water adsorbent and the hygroscopic salt are supported by the coating method, they are supported simultaneously or after the amorphous water adsorbent is supported. It is preferable to carry a salt. The coating liquid containing the hygroscopic salt and water mainly gathers around the amorphous moisture adsorbent, and after drying, the hygroscopic salt is selectively retained by the amorphous moisture adsorbent. Because it will be.

As the coating solution, a solution or dispersion containing an amorphous moisture adsorbent and a hygroscopic salt alone or in combination is used. As the medium, water or a mixed liquid of water and an organic solvent such as alcohol or ketone can be preferably used. For coating, an impregnation or coating apparatus such as a size press, a gate roll coater, an air knife coater, a blade coater, a comma coater, a bar coater, a gravure coater, or a kiss coater can be used. The drying temperature after coating is preferably 60 to 200 ° C, more preferably 80 to 150 ° C, and further preferably 90 to 140 ° C.

The solid content concentration of the solution or dispersion containing the amorphous water adsorbent and the hygroscopic salt alone or in combination is a web, a sheet-like substrate or a filtered sheet-like substrate (hereinafter referred to as “web etc.”). It is determined from the amount of the liquid retained in the medium such as a web obtained by coating only the medium and the amount of the amorphous water adsorbent or hygroscopic salt to be contained. For example, when a web containing an amorphous water adsorbent (amorphous water adsorbent content 45 mass% with respect to the web) contains 15 parts by mass of a hygroscopic salt with respect to 100 parts by mass of the amorphous water adsorbent. If the liquid retention amount is 200 parts by mass with respect to 100 parts by mass of the web, a coating liquid is prepared by dissolving or dispersing 6.75 parts by mass of the hygroscopic salt in 200 parts by mass of the medium.

Examples of the sheet-like substrate include porous substrates such as paper, porous film, woven fabric, dry nonwoven fabric, wet nonwoven fabric and knitted fabric, and nonporous substrates such as film and plate-like material. These base materials may be used alone, or may be laminated and combined by bonding or the like. Among the porous substrates, nonwoven fabrics in particular have a high porosity, and the coating composition and permeability of the coating liquid can be improved by the fiber configuration, and the amorphous moisture adsorbent present in the fiber matrix. Since the hygroscopic salt and the hygroscopic salt are not desorbed due to slippage of the substrate, it is a particularly suitable porous substrate.

Examples of the resin constituting the film, porous film, and plate-like material include olefin resin, polyester resin, polyvinyl acetate resin, ethylene vinyl acetate copolymer resin, polyamide resin, acrylic resin, polyvinyl chloride resin, Vinylidene chloride resin, polyvinyl ether resin, polyvinyl ketone resin, polyether resin, polyvinyl alcohol resin, diene resin, polyurethane resin, polycarbonate resin, cellulose resin, polyimide resin, phenol resin, melamine resin, furan resin, urea Resins, aniline resins, unsaturated polyester resins, alkyd resins, polyimide resins, fluororesins, silicone resins, and the like can be used. Moreover, as a porous film, inorganic porous films, such as a punching metal sheet, a foam metal sheet, and the aggregate film of an inorganic particle, can also be used. A metal foil or a metal plate may be used as the film or plate.

Paper, woven fabrics, dry nonwoven fabrics, wet nonwoven fabrics, and fibers constituting knitted fabrics include olefin resins, polyester resins, polyvinyl acetate resins, ethylene vinyl acetate copolymer resins, polyamide resins, acrylic resins, and polyvinyl chloride resins. , Polyvinylidene chloride resin, polyvinyl ether resin, polyvinyl ketone resin, polyether resin, polyvinyl alcohol resin, diene resin, polyurethane synthetic resin and other thermoplastic synthetic resins, phenol resin, melamine resin, furan resin, urea resin, aniline It is a fiber made of thermosetting resin such as resin, unsaturated polyester resin, alkyd resin. In addition, plant fibers such as wood pulp, cocoon, cocoon, cocoon, kenaf, bamboo, linter, bagasse, esparto, sugarcane, etc., or those made finer can be used, and rayon fibers that are cellulose regenerated fibers, Semi-synthetic fibers such as acetate, fluorine resin fibers such as polytetrafluoroethylene (PTFE), silicone resin fibers, metal fibers such as stainless steel and nickel wool, carbon fibers, ceramic fibers, and glass fibers can also be used.

The content of the amorphous water adsorbent in the dehumidifying sheet and filter material of the present invention is preferably 30 to 90% by mass, more preferably 35 to 80% by mass, and even more preferably 40 to 70% by mass. When the content of the amorphous moisture adsorbent is 30% by mass or more, a sufficient moisture adsorption amount is obtained, and when it is 90% by mass or less, the amorphous moisture adsorbent is obtained from the dehumidifying sheet or filter material. There is no risk of falling off.

The sheet material for dehumidification of the present invention may be used as it is, but can also be used by being laminated and composited with the above-mentioned sheet-like base material in order to increase the sheet strength. The sheet materials for dehumidification of the present invention may be laminated and combined.

Examples of the filtering method for producing the dehumidifying filter material of the present invention include pleating, corrugating, laminating, roll core processing, and donut processing. The sheet-like base material before filtering or the sheet material for dehumidification of the present invention may be improved in surface uniformity or the thickness may be adjusted by calendering or the like.

Next, the moisture absorbing / releasing sheet (6), the moisture absorbing / releasing structure (11) of the present invention, and the production methods thereof will be described.
The amorphous moisture absorbent according to the present invention is the same as the amorphous aluminum silicate. Amorphous aluminum silicate can be obtained in the same manner as described above.
The content of the amorphous hygroscopic agent used in the hygroscopic sheet of the present invention is 50 to 99% by mass with respect to the total (100% by mass) of the amorphous hygroscopic agent and the water-soluble silicate. 60 to 98% by mass is more preferable.

The water-soluble silicate contained in the moisture-absorbing / releasing sheet according to the present invention is not particularly limited as long as it is water-soluble, but preferably sodium silicate, disodium silicate, disodium silicate pentahydrate, silica At least one selected from the group consisting of disodium acid nonahydrate and potassium silicate is used. The water-soluble silicate is more preferably the same substance as the silicon compound that is the silicon source used in producing the amorphous hygroscopic agent. In particular, water glass that can also be used as a silicon source for an amorphous hygroscopic agent is most preferably used as the water-soluble silicate.

As a means for incorporating the amorphous moisture absorbent and the water-soluble silicate into the moisture-absorbing / releasing sheet of the present invention, a coating liquid in which the amorphous moisture-absorbing agent and the water-soluble silicate are dispersed and dissolved in the solvent. Is applied to or impregnated on one or both sides of a sheet base material, and a wet papermaking method is used in which a slurry in which an amorphous hygroscopic agent, a water-soluble silicate, and a fibrous material are dispersed and dissolved in a solvent. And paper making into a sheet.

The content of the water-soluble silicate is preferably 1 to 50% by mass, and more preferably 2 to 40% by mass with respect to the total (100% by mass) of the amorphous moisture absorbent and the water-soluble silicate. If the amount is less than 1% by mass, the strength of the coated product may be insufficient. If the amount exceeds 50% by mass, the effect of improving the hygroscopic performance may not be clear.

In addition to the amorphous hygroscopic agent and the water-soluble silicate, the coating liquid or the slurry may contain a dispersant for the purpose of dispersing the amorphous hygroscopic agent powder in the solvent. Examples of the dispersant include aliphatic metal salts, alkyl sulfonates, alkyl benzene sulfonates, quaternary ammonium salts, polyoxyethylene alkyl ethers, fatty acid polyhydric alcohol (glycerin, sorbitan, etc.) esters, polyacrylates, and the like. Polyacrylamide, polyethyleneimine, and the like can be used, but are not limited to the above compounds and can be used as appropriate. Note that the coating liquid or slurry may contain inevitable impurities.

As the sheet substrate used when the hygroscopic sheet of the present invention is obtained by coating or impregnating a coating liquid containing an amorphous hygroscopic agent and a water-soluble silicate, one having a fine structure is preferable. Paper, non-woven fabric, woven fabric, etc. can be used. The sheet base material is preferably made of a heat-resistant material after being impregnated or coated with a coating liquid, or after honeycomb processing and then subjected to a firing treatment. Materials that have heat resistance include carbon fiber, sepiolite fiber, glass fiber, alumina fiber, ceramic fiber such as alumina / silica fiber, silica fiber, etc., carbon fiber, paper using various high heat resistant synthetic fibers, non-woven fabric, woven fabric Can be mentioned.

The coating method of the coating liquid containing the amorphous hygroscopic agent and the water-soluble silicate is not particularly limited, and a general method can be used. For example, a spray coating method, a roll coating method, a curtain flow coating method, a curtain coating method, and a dip coating method can be exemplified. Among these, it is preferable to use a dip coating method, that is, an impregnation method, from the point that coating unevenness hardly occurs. Further, impregnation or coating may be performed not only once but two or more times. Moreover, you may coat several times combining a different method.

The coating amount of the coating liquid on the sheet base material is not particularly limited as long as the desired moisture absorption / release performance can be expressed, but is preferably 5 g / m ² or more and 100 g / m ² or less as a solid content. . If it is less than 5 g / m ^{2, the} moisture absorption / release property may be reduced, and even if it is applied in excess of 100 g / m ² , further improvement in moisture absorption / release performance may be reduced.

After coating the coating liquid on the sheet substrate, it is dried. If the moisture content after drying can be 10% or less, there are no particular limitations on the drying method and drying conditions. However, since cracks may occur in the coating layer when heated rapidly, it is more preferable to dry at a low temperature as a whole, or to dry under a temperature condition in which a gradient is gradually given from the low temperature region to the high temperature region. .

The fibrous material used when the moisture absorbing / releasing sheet of the present invention is obtained by making a paper containing a slurry containing an amorphous hygroscopic agent, a water-soluble silicate, and a fibrous material is the above-described fibrous material. In addition, ceramic fibers such as sepiolite fiber, alumina fiber, alumina / silica fiber, and silica fiber can be used. When a fiber that burns by firing at 920 ° C. or less is used as a fibrous material, the fibrous material contained in the slurry is burned off by the firing treatment. The loss of fibrous material after burnout may improve the porosity of the hygroscopic sheet surface, which may contribute to the improvement of the hygroscopic performance, but conversely the coated material on the hygroscopic sheet surface. In some cases, the strength may be lowered, and it is difficult to balance the moisture absorption / release performance and the strength of the coated object. Therefore, as the fibrous material, it is preferable to use ceramic fiber having high heat resistance, or metal fiber that does not disappear even when fired.

The content of the fibrous material is preferably 10 to 80% by mass, and preferably 20 to 70% by mass with respect to the total (100% by mass) of the amorphous hygroscopic agent, the water-soluble silicate, and the fibrous material. Is more preferable. Even if the fibrous material is less than 10% by mass or more than 80% by mass, the improvement in the strength of the coated article of the produced hygroscopic sheet may be reduced.

The wet papermaking method is an inexpensive method with high uniformity and capable of mass production. Specifically, for example, an amorphous hygroscopic agent, a water-soluble silicate, a slurry mainly comprising a fibrous material, and a filler, a dispersant, a thickener, an antifoaming agent, a paper strength enhancer, A sizing agent, a flocculant, a colorant, a fixing agent, and the like are added as appropriate, and wet papermaking is performed with a paper machine. As the paper machine, a circular paper machine, a long paper machine, a short paper machine, an inclined paper machine, a combination paper machine in which the same or different types of paper machines are combined among these, and the like can be used.

The sheet containing the amorphous hygroscopic agent and the water-soluble silicate may be dried and then subjected to honeycomb processing to form a honeycomb-like structure, followed by firing treatment to obtain a moisture-absorbing / releasing structure.
Since the sheet before the firing treatment is flexible and can be corrugated, a flat sheet and a corrugated sheet are prepared, and bonded with an inorganic binder such as colloidal silica, and laminated to form a honeycomb structure. be able to.
After the firing process, the sheet itself loses its flexibility and cannot be corrugated, but the moisture absorbent sheet according to the present invention after the firing process is cut to the required dimensions and combined to form a honeycomb-like moisture absorbent structure. Good.

In the hygroscopic structure in the present invention, a composition containing an amorphous hygroscopic agent and a water-soluble silicate may be supported on the surface of a structure that has already become a honeycomb.

The honeycomb structure may be produced by molding and firing an inorganic material such as alumina or cordierite, or a sheet of paper, non-woven fabric, woven fabric, film, metal, or the like may be processed into a honeycomb structure. You may have done. The shape of the honeycomb is not limited at all, such as a triangle, a quadrangle, a parallel hexagon, and a regular hexagon.

As a method for supporting a composition containing an amorphous hygroscopic agent and a water-soluble silicate on the surface of a honeycomb-shaped structure, a method of impregnating the structure into a coating liquid comprising the composition Is preferable because the thickness of the support layer can be adjusted by the number of impregnations and the solid content concentration of the coating liquid. When impregnating a plurality of times, after the first impregnation, the impregnation may be performed before drying, or after drying.
Drying is preferably natural drying, but drying may be performed in a hot-air circulating degreasing furnace, a general electric furnace, etc., and the drying temperature is not particularly limited, but should be as low as possible without causing any trouble in the work. Is preferred. Further, it is more preferable that the drying temperature can be gradually raised from a low temperature. It is preferable to dry until the moisture content of the honeycomb-shaped structure carrying the composition on the surface becomes 10% by mass or less.

As the composition containing the amorphous hygroscopic agent and the water-soluble silicate, the same coating liquid used when the hygroscopic sheet of the present invention is prepared by coating can be used. What is necessary is just to adjust solid content concentration of a coating liquid suitably from the ease of handling of a coating liquid, and the adhesion amount in one impregnation.

When the hygroscopic sheet or the hygroscopic structure is further loaded with a hygroscopic salt, the moisture absorption rate, that is, the hygroscopic capacity of the hygroscopic sheet and the hygroscopic structure can be improved.
As the hygroscopic salt, the above-mentioned compounds can be mentioned, but the hygroscopic salt can be appropriately used without being limited to the above compounds.

The method of supporting the hygroscopic salt is not particularly limited, but when it is supported on a sheet, a general method such as spray coating, roll coating, curtain flow coating, curtain coating, dip coating (impregnation) is used. Can be used. In addition, a method of impregnating a water-absorbing salt aqueous solution with a water-absorbing salt aqueous solution is the simplest and preferable, but an appropriate method is not limited to impregnation.

The method for producing a moisture absorbing / releasing sheet or moisture absorbing / releasing structure according to the present invention comprises supporting an amorphous moisture absorbent, a water-soluble silicate, and optionally a moisture absorbing salt on a sheet substrate or a honeycomb structure. And a step of firing the sheet base material or the honeycomb structure at a temperature of 920 ° C. or lower.

Here, firing is a method of high-temperature treatment widely used in the mineral processing industry such as ceramics, and its purpose includes chemical reactions such as thermal decomposition, synthesis and substitution, and sintering. Also, there are cases where the purpose is one of them and combinations of two or more. The firing temperature is appropriately selected according to the purpose, and there is no fixed processing temperature limit, and it ranges from 100 to 2000 ° C. or more.

In general, in the firing treatment of an inorganic material, the purpose is often sintering, that is, the compacting of a molded body made of an inorganic material is often performed, and the firing temperature is often set higher than 1000 ° C.
However, in the moisture absorbing / releasing sheet and the moisture absorbing / releasing structure containing only the amorphous hygroscopic agent without containing the water-soluble silicate, it is amorphous when the firing temperature during the firing treatment exceeds 920 ° C. It has been found that since the crystallization of the hygroscopic agent proceeds and grain growth occurs, the porosity is lost and the hygroscopic performance is deteriorated.
If the firing treatment is performed at a firing temperature of 920 ° C. or less, the moisture absorption / release performance of the amorphous moisture absorbent itself is not lowered. However, in the firing treatment at 920 ° C. or less, moisture absorption / desorption on the surfaces of the moisture absorption / release sheet and the moisture absorption / release structure is performed. When the agent cannot obtain sufficient strength and is used in a dehumidifying rotor as a moisture absorbing / releasing structure, it absorbs and releases moisture as a moisture absorbing / releasing structure due to powder falling off due to a decrease in strength while used for a long time. A decrease in performance was observed. Therefore, it has been found that it is difficult to balance moisture absorption / release performance and strength characteristics only under the firing treatment conditions.
Therefore, as a result of intensive studies, sufficient moisture absorption and desorption can be achieved by firing the moisture absorbing / releasing sheet and the moisture absorbing / releasing structure containing the amorphous moisture absorbent and the water-soluble silicate at a temperature of 920 ° C. or lower. It has been found that there is almost no deterioration in the moisture absorption / release characteristics during long-term use while maintaining the moisture characteristics.

The firing temperature may be determined in consideration of the heat resistance of the sheet base material or the structure material. In general, in the temperature range of 300 to 400 ° C., there is a case where it does not generally correspond to firing, and in the present invention, the firing treatment at a temperature of 400 ° C. or less may be less effective. Therefore, it is preferable that the moisture absorbing / releasing sheet and the moisture absorbing / releasing structure of the present invention are fired in a firing temperature range of 400 ° C. to 920 ° C., in order to easily balance moisture absorption performance and strength. When a sheet base material and a structural material having high heat resistance are used, it is more preferable to perform a baking treatment in a temperature range of 500 ° C. to 920 ° C. The firing time is preferably 1 hour or longer.

The furnace used for the firing treatment is preferably a hot air circulation type degreasing furnace. When the moisture-absorbing / releasing sheet according to the present invention is fired, a type in which the sheet is continuously fed into the furnace is preferable, but a batch type in which the sheet is fired in a lump in a wound form may be used. When the moisture absorbing / releasing structure is sintered, it is preferable to simultaneously process a plurality of batch type at a time.

The adsorbing sheet (16) of the present invention comprises an adsorbing layer containing at least an adsorbing agent and a binder on a sheet substrate, and the adsorbing agent is the amorphous aluminum silicate. Salt (hereinafter referred to as “amorphous adsorbent”).

The coating liquid (21) constituting the adsorption layer of the adsorption sheet of the present invention contains at least an adsorbent, a binder and a medium, and the adsorbent is the amorphous aluminum silicate, The medium is an organic solvent, and the binder is an organic solvent-soluble polymer.

The amorphous aluminum silicate used as the amorphous adsorbent can be produced in the same manner as described above.
Since the amorphous adsorbent has a high surface activity, the adsorbed amount of moisture and the like is large, but the binder is also easily adhered, and there arises a problem that the adsorbing property of the adsorbing sheet is deteriorated. Conventionally used water-insoluble polymer emulsions are provided with functional groups such as anionic groups and cationic groups in order to enhance the dispersion stability in water. For this reason, the water-insoluble polymer tends to adhere to the amorphous adsorbent, and forms a film on the surface, thereby reducing the adsorption characteristics.
In addition, in a coating solution containing an amorphous adsorbent, when an emulsion of a water-insoluble polymer that has been conventionally used as a binder is used and dispersed in water, the amorphous adsorbent is insoluble in water. Since the polymer emulsion is easy to adhere, the coating solution is gelled or the emulsion or adsorbent is precipitated.

Therefore, the adsorption sheet of the present invention preferably uses an organic solvent-soluble polymer as a binder. In the present invention, the organic solvent-soluble polymer is a polymer that has a dielectric constant lower than that of water and can be dissolved in an organic solvent. As long as it satisfies this, the molecular weight of the organic solvent-soluble polymer is not particularly limited, but preferably has a mass average molecular weight of 10,000 to 2,000,000. Organic solvent-soluble polymers have little interaction with amorphous adsorbents, so when used as binders, it is difficult to form a film on the surface of amorphous adsorbents, and adsorption characteristics such as moisture The decrease can be suppressed.

In addition, when an organic solvent is used as a medium and an organic solvent-soluble polymer is used as a binder as in the coating liquid of the present invention, the binder does not easily adhere to the amorphous adsorbent, and the coating Gelation and sedimentation of the liquid can be suppressed, and production stability of the adsorption sheet can be obtained. Moreover, when the coating liquid of this invention is used, since the coating liquid is hard to gelatinize, the adsorption | suction sheet | seat with which the adsorption agent was carry | supported uniformly is obtained.

Examples of organic solvent-soluble polymers include vinyl acetate-ethylene copolymer, vinyl chloride-ethylene copolymer, vinyl chloride-vinyl acetate-ethylene copolymer, poly (meth) acrylate, polyester, polyurethane, polyethylene, Polybutadiene, polyisobutylene, polypropylene, polystyrene-butadiene, polystyrene, polychloroprene, vinylidene chloride- (meth) acrylonitrile copolymer, alkoxyalkylated nylon, polydimethylsiloxane, polyvinyl acetal, vinylidene fluoride polymer, tetrafluoroethylene- Vinylidene fluoride copolymer, butyl rubber, natural rubber, hydrogenated polybutadiene, butadiene-styrene copolymer, nitrile rubber, polysulfide, polyvinylidene chloride, poly (meth) acrylate Nitrile, and the like. Among these, it is preferable to use a vinylidene fluoride polymer or N-alkoxyalkylated polyamide. Further, it is more preferable to use N-alkoxyalkylated polyamide.

When a vinylidene fluoride polymer or N-alkoxyalkylated polyamide is used as the organic solvent-soluble polymer, there is no functional group that can be easily adsorbed on the surface of the amorphous adsorbent in any polymer. However, the interaction with the amorphous adsorbent is smaller, and the surface of the amorphous adsorbent is difficult to coat, but the sheet base material and the amorphous adsorbent are firmly bonded. Dropping from the sheet base material can be suppressed. Furthermore, since N-alkoxyalkylated polyamide is a material through which moisture and the like are easy to permeate, even if N-alkoxyalkylated polyamide is present on the surface of the amorphous adsorbent, it can further suppress a decrease in adsorption characteristics. it can.

The vinylidene fluoride polymer in the present invention includes poly (vinylidene fluoride-hexafluoropropylene) copolymer, poly (vinylidene fluoride-perfluorovinyl ether) copolymer, poly (vinylidene fluoride), in addition to polyvinylidene fluoride. Ride-tetrafluoroethylene) copolymer, poly (vinylidene fluoride-hexafluoropropylene oxide) copolymer, poly (vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene oxide) copolymer, poly (vinylidene fluoride-) Hexafluoropropylene-tetrafluoroethylene) copolymer. These vinylidene fluoride component-containing polymers can be used alone or in a mixture. The weight average molecular weight of the vinylidene fluoride polymer is preferably 100,000 to 2,000,000, more preferably 150,000 to 500,000.

The N-alkoxyalkylated polyamide is an alkoxyalkylated NH hydrogen atom present in the main chain of the polyamide. As the polyamide, those obtained by polycondensation reaction of ω amino acids or co-condensation polymerization of amine and dicarboxylic acid can be used. For example, N-methoxymethylated polyamide is synthesized by reacting polyamide with formaldehyde in the presence of a lower alcohol such as methanol in an acid solvent that dissolves polyamide such as formic acid. Specific examples of alkoxyalkyl other than methoxymethyl include ethoxymethyl, n-butoxymethyl, n-hexyloxymethyl, (2-ethylbutyloxy) methyl, n-octyloxymethyl, n-decyloxymethyl, 2-methoxy Ethyl, 2-ethoxyethyl, 2-n-propoxyethyl, 2-isopropoxyethyl, 2-n-butoxyethyl, 2-n-pentyloxyethyl, 2-n-hexyloxyethyl, 2- (2'-ethyl) Butyloxy) ethyl, 2-n-heptyloxyethyl, 2-n-octyloxyethyl, 2- (2'-ethylhexyloxy) ethyl, 2-n-decyloxyethyl, 2-n-dodecyloxyethyl, 2- n-tetradecyloxyethyl, 2-cyclohexyloxyethyl, 2-methoxypropyl, -Methoxypropyl, 3-ethoxypropyl, 3-n-propoxypropyl, 3-isopropoxypropyl, 3-n-butoxypropyl, 3-n-pentyloxypropyl, 3-n-hexyloxypropyl, 3- (2 ' -Ethylbutoxy) propyl, 3-n-octyloxypropyl, 3- (2'-ethylhexyloxy) propyl, 3-n-decyloxypropyl, 3-n-dodecyloxypropyl, 3-n-tetradecyloxypropyl, 3-cyclohexyloxypropyl, 4-methoxybutyl, 4-ethoxybutyl, 4-n-propoxybutyl, 4-isopropoxybutyl, 4-n-butoxybutyl, 4-n-hexyloxybutyl, 4-n-octyloxy Butyl, 4-n-decyloxybutyl, 4-n-dodecyloxybuty 5-methoxypentyl, 5-ethoxypentyl, 5-n-propoxypentyl, 6-ethoxyhexyl, 6-isopropoxyhexyl, 6-n-butoxyhexyl, 6-n-hexyloxyhexyl, 6-n-decyloxy Hexyl, 4-methoxycyclohexyl, 7-ethoxyheptyl, 7-isopropoxyheptyl, 8-methoxyoctyl, 10-methoxydecyl, 10-n-butoxydecyl, 12-ethoxydodecyl, 12-isopropoxidedecyl, tetrahydrofurfuryl, etc. Can be mentioned. The mass average molecular weight of the N-alkoxyalkylated polyamide is preferably 10,000 to 100,000, more preferably 15,000 to 50,000.

Examples of the organic solvent used in the coating liquid of the present invention include alcohol solvents such as methanol, ethanol and isopropyl alcohol; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ethyl formate, ethyl acetate and n acetate. Ester solvents such as butyl; ether solvents such as diethyl ether, 1,2-dimethoxyethane, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, anisole; N, N-dimethylformamide, N, N— Amide solvents such as dimethylacetamide and N-methyl-2-pyrrolidone; dichloromethane, chloroform, bromoform, methyl iodide, dichloroethane, trichloroethane, trichloroethylene, chlorobenzene, o-dichlorobenzene, fluorobenzene Halogenated hydrocarbon solvents such as bromobenzene, iodobenzene, α-chloronaphthalene; n-pentane, n-hexane, n-octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene, benzene, toluene, Examples thereof include hydrocarbon solvents such as o-xylene, m-xylene, p-xylene, ethylbenzene and cumene. Among these, it is preferable to use an alcohol solvent, a ketone solvent, or an amide solvent. By using these organic solvents, the coating liquid is hardly gelled, exhibits high dispersibility, and has good coating properties. Alcohol solvents and amide solvents are particularly preferred. These organic solvents can be used alone or in admixture of two or more.

The mass ratio of the amorphous adsorbent to the binder in the adsorption layer is preferably 93/7 to 70/30, more preferably 92/8 to 75/25, and still more preferably 92/8 to 85/15. In the mass ratio between the amorphous adsorbent and the binder in the adsorption layer, if the content ratio of the binder exceeds 30% by mass, the adsorptive properties are reduced, or the dispersibility of the coating liquid is reduced. It may gel. In addition, when the content ratio of the binder is less than 7% by mass, the adsorbent may fall off from the sheet base material.

The total concentration of the amorphous adsorbent and the binder in the coating liquid is preferably 12 to 50% by weight, more preferably 15 to 45% by weight, based on the total amount of the coating liquid (100% by weight). More preferably, it is 18 to 40% by mass. If the total concentration of the amorphous adsorbent and the binder in the coating liquid is less than 12% by mass, the coating amount may be too low to satisfy the required adsorption characteristics of the adsorption sheet. When the total concentration of the amorphous adsorbent and the binder in the coating liquid exceeds 50% by mass, the dispersion stability of the coating liquid may be lowered.

In the production of the coating liquid, after manufacturing an adsorbent dispersion in which an amorphous adsorbent is dispersed in an organic solvent, the adsorbent dispersion and a binder or a mixture of the binder and the organic solvent Are preferably mixed to produce a coating solution. Dispersers using dispersion media such as ball mills, paint conditioners, vertical bead mills, horizontal (horizontal) bead mills, and attritors should be used as the equipment used to disperse amorphous adsorbents in organic solvents. Can do. As the material of the dispersion medium, soda glass, low alkali glass, and yttria-containing zirconia are preferable, and beads having a diameter of several mm can be used.

The adsorbing sheet of the present invention forms an adsorbing layer by applying a coating liquid containing at least an amorphous adsorbent and a binder to a sheet substrate and drying it as necessary. A sheet for adsorption comprising an adsorption layer on a sheet substrate can be produced. The above-described impregnation or coating apparatus can be used for coating.

The coating amount for coating the coating liquid on the sheet base material can be appropriately set according to the required adsorption characteristics, and is not particularly limited, but is an amorphous adsorbent for the adsorption sheet. Is preferably 10 to 200 g / m ² , more preferably 20 to 100 g / m ² , and still more preferably 40 to 70 g / m ² . If it exceeds 200 g / m ² , the amorphous adsorbent inside the adsorption layer may not contribute to the adsorption. If it is less than 10 g / m ² , the desired adsorption characteristics may not be achieved.

The sheet substrate includes the porous substrate and the nonporous substrate described above. These base materials may be used alone, or may be laminated and combined by bonding or the like.

As the fibers constituting paper, woven fabric, dry nonwoven fabric, wet nonwoven fabric, and knitted fabric, the above-described fibrous materials can be used.

The resin described above can be used as the resin constituting the film, porous film, and plate-like material. Moreover, as a porous film, an above described inorganic porous film can also be used. As the film or plate-like material, a metal foil or a metal plate may be used as described above.

The adsorption sheet of the present invention may be used as it is, or may be used after being subjected to secondary processing such as pleating processing, corrugating processing, laminating processing, roll core processing, and donut processing. The secondary processing may be performed after the adsorption layer is applied to the sheet base material, or the sheet base material may be secondarily processed and the adsorption layer may be applied first.

In the adsorbing sheet of the present invention, a substance that reinforces the adsorption characteristics of the amorphous adsorbent (reinforcing substance) can be supported on the amorphous adsorbent or contained in the adsorption layer. For example, metals, metal ions; metal halide salts such as lithium chloride, calcium chloride, and magnesium chloride; metal sulfates such as sodium sulfate, calcium sulfate, magnesium sulfate, and zinc sulfate; metal acetates such as potassium acetate; dimethylamine hydrochloride Amine salts such as orthophosphoric acid compounds; guanidine hydrochloride such as guanidine hydrochloride, guanidine phosphate, guanidine sulfamate; metal hydroxides such as potassium hydroxide, sodium hydroxide, magnesium hydroxide, etc .; ionic liquid A porous material such as silica gel, activated carbon, zeolite, and the like. These reinforcing substances may be added to the adsorbent coating liquid, or after the adsorbent layer is provided, the reinforcing substance coating liquid can be applied.

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

<Synthesis of amorphous moisture adsorbent 1>
400 ml of an aqueous sodium orthosilicate solution diluted with pure water was prepared so that the Si concentration was 383 mmol / L. Separately, aluminum chloride was dissolved in pure water to prepare 400 ml of an aqueous solution having an Al concentration of 450 mmol / L. Next, the sodium orthosilicate aqueous solution was mixed with the aluminum chloride aqueous solution and stirred with a magnetic stirrer. The Si / Al ratio at this time was 0.85. Further, 18 ml of 1N aqueous sodium hydroxide solution was added dropwise to the mixed solution to adjust the pH to 7. The precursor was recovered from this solution by centrifugation and dispersed in 4 L of pure water. After stirring at room temperature for 1 hour, the mixture was transferred to a 4 L sealed container and heated at 98 ° C. for 2 days in a thermostatic bath. After cooling, it was washed three times by centrifugation and then dried at 60 ° C. to obtain an amorphous water adsorbent 1.

In the ²⁹ Si solid state NMR measurement of the amorphous water adsorbent 1, peaks were confirmed in the vicinity of −78 ppm and −87 ppm. Moreover, in the powder X-ray diffraction measurement, broad peaks were confirmed around 2θ = 27 ° and 40 °. When the amorphous water adsorbent was observed with a transmission electron microscope and a scanning electron microscope, the primary particle diameter of the single particles was 2 to 5 nm, and the particle diameter of the composite particles was 2 to 40 nm. The particle diameter of the quasi-mesopores present in the aggregated structure was 2 to 20 nm.

<Synthesis of amorphous moisture adsorbent 2>
2 L of water glass solution diluted with pure water was adjusted so that the Si concentration was 800 mmol / L. Separately, aluminum sulfate was dissolved in pure water to prepare 2 L of an aluminum sulfate aqueous solution having an Al concentration of 940 mmol / L. Next, an aqueous aluminum sulfate solution was mixed with an aqueous water glass solution and stirred with a stirrer. The Si / Al ratio at this time was 0.85. Furthermore, 600 mL of 5N aqueous sodium hydroxide solution was added to this mixed solution to adjust the pH to 7. This solution was stirred at room temperature for 30 minutes, then transferred to a 5 L sealed container, and heated at 95 ° C. for 1 day in a thermostatic bath. Thus, an aqueous solution containing amorphous aluminum silicate was obtained. After cooling, it was washed four times by centrifugation and then dried at 60 ° C. to obtain an amorphous water adsorbent 2.

When the ²⁹ Si solid state NMR spectrum of the obtained amorphous moisture adsorbent 2 was measured, peaks were confirmed in the vicinity of -78 ppm, -87 ppm, and -92 ppm. Moreover, in the powder X-ray diffraction measurement, broad peaks were confirmed around 2θ = 27 ° and 40 °. When the amorphous water adsorbent was observed with a transmission electron microscope and a scanning electron microscope, the primary particle diameter of the single particles was 2 to 5 nm, the particle diameter of the composite particles was 2 to 40 nm, and the aggregate structure The particle diameter was 0.1 to 100 μm, and the pseudo mesopores present in the aggregated structure had a pore diameter of 2 to 20 nm.

Example 1
100 g of the amorphous water adsorbent 1 is put in a polytetrafluoroethylene container, 50 g of a 20 mass% magnesium chloride aqueous solution is added while stirring with a stirrer equipped with a stirring blade, and drying is performed at 80 ° C. for 6 hours. The water adsorbent of Example 1 was obtained by regrinding.

(Example 2)
A water adsorbent of Example 2 was obtained in the same manner as in Example 1 except that the addition amount of the 20 mass% magnesium chloride aqueous solution was changed to 100 g.

(Example 3)
A water adsorbent of Example 3 was obtained in the same manner as in Example 1 except that the amount of the 20 mass% magnesium chloride aqueous solution added was changed to 200 g.

Example 4
A water adsorbent of Example 4 was obtained in the same manner as in Example 1 except that the addition amount of the 20 mass% magnesium chloride aqueous solution was changed to 500 g and the drying time was changed to 20 hours.

(Example 5)
100 g of the amorphous water adsorbent 1 was placed in a polytetrafluoroethylene container, and 20 g of a 5% by mass magnesium chloride aqueous solution was sprayed and stirred for 10 minutes while stirring with a stirrer equipped with a stirring blade. Then, it dried at 80 degreeC for 6 hours, and obtained the water | moisture-content adsorption agent of Example 5. FIG.

(Example 6)
100 g of the amorphous water adsorbent 1 was placed in a polytetrafluoroethylene container, and 40 g of a 5% by mass magnesium chloride aqueous solution was sprayed and stirred for 10 minutes while stirring with a stirrer equipped with a stirring blade. Thereafter, drying was performed at 80 ° C. for 6 hours to obtain a moisture adsorbent of Example 6.

(Example 7)
100 g of the amorphous water adsorbent 1 was placed in a polytetrafluoroethylene container, and 16 g of a 5 mass% magnesium chloride aqueous solution was sprayed and stirred for 10 minutes while stirring with a stirrer equipped with a stirring blade. Thereafter, drying was performed at 80 ° C. for 6 hours to obtain a moisture adsorbent of Example 7.

(Example 8)
A water adsorbent of Example 8 was obtained in the same manner as in Example 1 except that the addition amount of the 20 mass% magnesium chloride aqueous solution was changed to 550 g and the drying time was changed to 20 hours.

Example 9
A water adsorbent of Example 9 was obtained in the same manner as in Example 1 except that the amorphous water adsorbent 2 was used instead of the amorphous water adsorbent 1.

(Comparative Example 1)
Comparative Example 1 was carried out in the same manner as in Example 1 except that silica gel (trade name: silica gel B, specific surface area 450 m ² / g by BET method, manufactured by Toyoda Chemical Industries) was used instead of amorphous moisture adsorbent 1. Water adsorbent was obtained.

(Comparative Example 2)
The moisture adsorption of Comparative Example 2 was performed in the same manner as in Example 1 except that zeolite (trade name: 13X, manufactured by Junsei Chemical Co., Ltd., pore diameter (catalog value) 1 nm) was used instead of the amorphous moisture adsorbent 1. An agent was obtained.

(Comparative Example 3)
<Synthesis of mesoporous silica>
To 240 parts by mass of pure water, 1.75 parts by mass of a 2N sodium hydroxide aqueous solution, 0.5 parts by mass of cetyltrimethylmethylammonium bromide and 2.5 parts of tetraethoxysilane were added, and heated at 90 ° C. for 2 hours. Thus, a mesoporous silica precursor was obtained. Furthermore, the organic substance was removed by heating at 600 ° C. for 3 hours to obtain mesoporous silica. The specific surface area of the obtained mesoporous silica was 1000 m ² / g, and the pore diameter was 1.5 nm as measured by transmission electron microscope.

<Production of moisture adsorbent>
A water adsorbent of Comparative Example 3 was obtained in the same manner as in Example 1 except that mesoporous silica was used instead of the amorphous water adsorbent 1.

(Comparative Examples 4 to 8)
Amorphous moisture adsorbents 1 and 2, silica gel used in Comparative Example 1, zeolite used in Comparative Example 2, and mesoporous silica synthesized in Comparative Example 3 were used in Comparative Examples 4 to 8 without using hygroscopic salts. The moisture adsorbent was used.

[Evaluation 1: Moisture adsorption test]
The water absorbent obtained in Examples 1-9 and Comparative Examples 1-8 removed 0.5g, dried 2 hours at 90 ° C. by measuring the mass, which was used as a dry weight W _D. Next, it was allowed to stand at 25 ° C. and a relative humidity of 30% (low humidity atmosphere) for 2 hours, and the mass W ₃₀ was measured. Subsequently, with the temperature kept at 25 ° C., the relative humidity was increased to 50% (medium humidity atmosphere) and left for 2 hours, and the mass W ₅₀ was measured. Furthermore, with the temperature kept at 25 ° C., the relative humidity was increased to 90% (high humidity atmosphere) and left for 2 hours, and the mass W ₉₀ was measured. From the following formulas (1) to (3), the moisture adsorption amounts A ₃₀ , A ₅₀ , A ₉₀ (%) were measured, and the results are shown in Table 1.
A ₃₀ (%) = (W ₃₀ −W _D ) / W _D × 100 (1)
A ₅₀ (%) = (W ₅₀ −W _D ) / W _D × 100 (2)
A ₉₀ (%) = (W ₉₀ −W _D ) / W _D × 100 (3)

[Evaluation 2: Drying test]
Mass W ₉₀ was dry test after measuring. That is, it dried 2 hours at 90 ° C. by measuring the mass _{W L} and was calculated from equation (4), dryness D (percent). The dryness D was 40% or less as “◯”, 40% or more and less than 80% as “Δ”, and 80% or more as “x”.
D (%) = (W _L −W _D ) / (W ₉₀ −W _D ) × 100 (4)

The water adsorbents of Examples 1 to 9 containing the amorphous water adsorbent and the hygroscopic salt were higher in the medium than the water adsorbents of Comparative Examples 4 and 5 consisting only of the amorphous water adsorbent. Moisture adsorption was improved in all low-humidity atmospheres. Moreover, when the content of the hygroscopic salt increased, a tendency for the moisture adsorption amount to increase was confirmed. On the other hand, as can be seen from Comparative Examples 1 and 6, in the case of silica gel, even when a hygroscopic salt was added, the moisture adsorption amount increased only slightly. Further, as can be seen from Comparative Examples 2 and 7, in zeolite, even when a hygroscopic salt was added, the amount of moisture adsorption increased only slightly, and water was not desorbed in the drying test. As can be seen from Comparative Examples 3 and 8, in the case of mesoporous silica, when a hygroscopic salt was added, the moisture adsorption amount was decreased.
From the results shown in Table 1, the moisture adsorbents of Examples 1 to 9 showed an excellent moisture adsorption amount in a low humidity atmosphere, which was difficult to improve, compared with the moisture adsorbents of Comparative Examples 1 to 8, and low It was confirmed that this excellent effect was sustained in all of the medium and high humidity atmospheres. Therefore, the water adsorbent of the present invention is predicted from a conventionally known adsorbent alone (Comparative Examples 4 to 8) or a porous water adsorbent carrying a hygroscopic salt (Comparative Examples 1 to 3). It is clear that it has surprisingly excellent effects in all the high, medium and low humidity atmospheres that cannot be obtained.

(Example 10)
Using amorphous water adsorbent 2, a papermaking slurry (solid content concentration: 1.2% by mass) was prepared with the following constitution (in terms of dry mass).

Polyester fiber (fineness: 0.11 dtex, fiber length: 3 mm) 22% by mass
Polyester core / sheath binder fiber (fineness: 1.1 dtex, fiber length: 3 mm, melting point 115 ° C.) 18% by mass
7% by mass of fibrillated cellulose fiber
Amorphous moisture adsorbent 2 53% by mass

A flocculant (trade name: Percoll 57, Ciba Specialty Chemicals) was added to the obtained slurry in an amount of 0.2% by mass based on the total solid content, and a web was obtained by making paper with a circular net type paper machine. The obtained web had a basis weight of 50 g / m ² and the content of the amorphous water adsorbent 2 was 45% by mass based on the ash content measurement method.

Next, a 20 μm-thick polyethylene film was placed in the center and the web was bonded from both sides through a heat calender roll (temperature: 150 ° C.) to prepare a bonded sheet material having a basis weight of 118 g / m ² and a thickness of 160 μm. Subsequently, a magnesium chloride aqueous solution having a concentration of 5% by mass was prepared and impregnated on both sides of the sheet to obtain a dehumidifying sheet material of Example 10 containing magnesium chloride (hygroscopic salt). The content of magnesium chloride (hygroscopic salt) was 5% by mass with respect to the dehumidifying sheet, and 13% by mass with respect to the amorphous moisture adsorbent.

The obtained sheet material for dehumidification was subjected to corrugation to produce a columnar dehumidification filter material of Example 10 having a diameter of 10 cm and a length of 10 cm.

(Examples 11 to 13)
Dehumidifying sheet materials and dehumidifying filter materials of Examples 11 to 13 were produced in the same manner as in Example 10 except that the concentration of the magnesium chloride aqueous solution was changed to 0.2, 1, and 8% by mass, respectively. The contents of magnesium chloride (hygroscopic salt) in Examples 11 to 13 are 0.2, 1, and 8% by mass, respectively, with respect to the dehumidifying sheet, and 0.8% with respect to the amorphous moisture adsorbent. It was 5, 3, 21% by mass.

(Example 14)
A dehumidifying sheet material and a dehumidifying filter material of Example 14 were prepared in the same manner as in Example 10 except that a 1% by mass lithium chloride aqueous solution was used instead of the 5% by mass magnesium chloride aqueous solution. did. The content of lithium chloride (hygroscopic salt) was 1% by mass with respect to the dehumidifying sheet, and 3% by mass with respect to the amorphous moisture adsorbent.

(Example 15)
A dehumidifying sheet and a dehumidifying filter material of Example 15 were produced in the same manner as in Example 10 except that a sodium chloride aqueous solution having a concentration of 5% by mass was used instead of the magnesium chloride aqueous solution having a concentration of 5% by mass. did. The content of sodium chloride (hygroscopic salt) was 8% by mass with respect to the dehumidifying sheet, and 21% by mass with respect to the amorphous moisture adsorbent.

(Example 16)
The dehumidifying sheet and the dehumidifying filter material of Example 16 were obtained in the same manner as in Example 10 except that a 15% by mass guanidine sulfamate aqueous solution was used instead of the 5% by mass magnesium chloride aqueous solution. Produced. The content of guanidine sulfamate (hygroscopic salt) was 15% by mass with respect to the dehumidifying sheet and 39% by mass with respect to the amorphous moisture adsorbent.

(Example 17)
For dehumidification of Example 17, except that a mixed aqueous solution of 15% by mass of guanidine sulfamate and 5% by mass of magnesium chloride was used instead of the 5% by mass of magnesium chloride aqueous solution. A sheet-like material and a filter material for dehumidification were prepared. The content of guanidine sulfamate (hygroscopic salt) was 15% by mass with respect to the dehumidifying sheet and 39% by mass with respect to the amorphous moisture adsorbent. The content of magnesium chloride (hygroscopic salt) was 5% by mass with respect to the dehumidifying sheet, and 13% by mass with respect to the amorphous moisture adsorbent.

(Comparative Example 9)
A bonded sheet material having a basis weight of 118 g / m ² and a thickness of 160 μm obtained in Example 10 was produced, and a dehumidifying sheet material of Comparative Example 9 was obtained without applying a hygroscopic salt. This was corrugated to produce a dehumidifying filter material of Comparative Example 9 having a columnar shape of 10 cmφ and 10 cm in length.

(Comparative Example 10)
Using commercially available silica gel (trade name: Silica gel B, specific surface area 450 m ² / g by BET method, manufactured by Toyoda Chemical Industries), papermaking slurry (solid content concentration 1.2% by mass) with the following configuration (dry mass conversion) Was prepared.

Polyester fiber (fineness: 0.11 dtex, fiber length: 3 mm) 22% by mass
Polyester core / sheath binder fiber (fineness: 1.1 dtex, fiber length: 3 mm, melting point 115 ° C.) 18% by mass
7% by mass of fibrillated cellulose fiber
Silica gel 53% by mass

A flocculant (trade name: Percoll 57, Ciba Specialty Chemicals) was added to the obtained slurry in an amount of 0.2% by mass based on the total solid content, and a web was obtained by making paper with a circular net type paper machine. The obtained web had a basis weight of 50 g / m ² , and the content of silica gel was 45% by mass based on the ash content measurement method.

Next, a 20 μm thick polyethylene film was used as the center to bond the webs from both sides to produce a bonded sheet material having a basis weight of 118 g / m ² and a thickness of 160 μm, which was used as the dehumidifying sheet material of Comparative Example 10. .

The obtained sheet material for dehumidification was subjected to corrugation (step height: 1.9 mm, pitch: 3.2 mm) to prepare a dehumidifying filter material of Comparative Example 10 having a columnar shape of 10 cmφ and 10 cm in length.

(Comparative Example 11)
Comparison in which magnesium chloride aqueous solution having a concentration of 5% by mass was coated on both surfaces of a bonded sheet-like material having a basis weight of 118 g / m ² and a thickness of 160 μm obtained in Comparative Example 10 to contain magnesium chloride (hygroscopic salt). The sheet material for dehumidification of Example 11 was produced. The content of magnesium chloride (hygroscopic salt) was 5% by mass with respect to the dehumidifying sheet, and 13% by mass with respect to the silica gel. The obtained dehumidified sheet was subjected to corrugating (step height: 1.9 mm, pitch: 3.2 mm) to produce a dehumidifying filter material of Comparative Example 11 having a columnar shape of 10 cmφ and length of 100 mm.

(Comparative Example 12)
Using a commercially available zeolite (trade name: 13X, manufactured by Junsei Chemical Co., Ltd.), a papermaking slurry (solid content concentration 1.2% by mass) was prepared with the following constitution (in terms of dry mass).

Polyester fiber (fineness: 0.11 dtex, fiber length: 3 mm) 22% by mass
Polyester core / sheath binder fiber (fineness: 1.1 dtex, fiber length: 3 mm, melting point 115 ° C.) 18% by mass
7% by mass of fibrillated cellulose fiber
Zeolite 53% by mass

A flocculant (trade name: Percoll 57, Ciba Specialty Chemicals) was added to the obtained slurry in an amount of 0.2% by mass based on the total solid content, and a web was obtained by making paper with a circular net type paper machine. The obtained web had a basis weight of 50 g / m ² , and the zeolite content was 45% by mass based on the ash content measurement method.

Next, a 20 μm thick polyethylene film was used as the center to bond the webs from both sides to produce a bonded sheet material having a basis weight of 118 g / m ² and a thickness of 160 μm, which was used as the dehumidifying sheet material of Comparative Example 12. .

Corrugation processing (step height: 1.9 mm, pitch: 3.2 mm) was applied to the obtained sheet for comparative dehumidification, and a dehumidification filter material of Comparative Example 12 having a columnar shape of 10 cmφ and 10 cm in length was produced.

(Comparative Example 13)
Comparison in which a magnesium chloride aqueous solution having a concentration of 5% by mass was applied to both surfaces of a bonded sheet-like material having a basis weight of 118 g / m ² and a thickness of 160 μm obtained in Comparative Example 12 to contain magnesium chloride (hygroscopic salt). The sheet material for dehumidification of Example 13 was produced. The content of magnesium chloride (hygroscopic salt) was 5% by mass with respect to the dehumidifying sheet, and 13% by mass with respect to zeolite. The obtained dehumidifying sheet was subjected to corrugating (step height: 1.9 mm, pitch: 3.2 mm) to produce a dehumidifying filter material of Comparative Example 13 having a columnar shape of 10 cmφ and length of 100 mm.

(Comparative Example 14)
Using the mesoporous silica synthesized in Comparative Example 3, a papermaking slurry (solid content concentration: 1.2% by mass) was prepared with the following configuration (in terms of dry mass).

Polyester fiber (fineness: 0.11 dtex, fiber length: 3 mm) 22% by mass
Polyester core / sheath binder fiber (fineness: 1.1 dtex, fiber length: 3 mm, melting point 115 ° C.) 18% by mass
7% by mass of fibrillated cellulose fiber
Mesoporous silica 53% by mass

A flocculant (trade name: Percoll 57, Ciba Specialty Chemicals) was added to the obtained slurry in an amount of 0.2% by mass based on the total solid content, and a web was obtained by making paper with a circular net type paper machine. The obtained web had a basis weight of 50 g / m ² , and the mesoporous silica content was 45% by mass based on the ash content measurement method.

Next, a 20 μm thick polyethylene film was used as the center to bond the webs from both sides to produce a bonded sheet material having a basis weight of 118 g / m ² and a thickness of 160 μm, which was used as the dehumidifying sheet material of Comparative Example 14. .

The obtained sheet material for dehumidification was subjected to corrugation (step height: 1.9 mm, pitch: 3.2 mm), and a dehumidifying filter material of Comparative Example 14 having a columnar shape of 10 cmφ and 10 cm in length was produced.

(Comparative Example 15)
Comparison in which magnesium chloride aqueous solution having a concentration of 5% by mass was coated on both surfaces of a bonded sheet-like material having a basis weight of 118 g / m ² and a thickness of 160 μm obtained in Comparative Example 14 to contain magnesium chloride (hygroscopic salt). The sheet material for dehumidification of Example 15 was produced. The content of magnesium chloride (hygroscopic salt) was 5% by mass with respect to the dehumidifying sheet, and 13% by mass with respect to mesoporous silica. The obtained dehumidified sheet was subjected to corrugation (step height: 1.9 mm, pitch: 3.2 mm) to produce a dehumidifying filter material of Comparative Example 15 having a columnar shape of 10 cmφ and length of 100 mm.

(Comparative Example 16)
A papermaking slurry (solid content concentration 1.2% by mass) was prepared with the following constitution (in terms of dry mass).

Polyester-based sheath / core binder fiber (fineness: 1.1 dtex, fiber length: 3 mm, melting point 115 ° C.) 25% by mass
Pulp (LBKP) 75% by mass

Using the obtained slurry, a web was obtained by making paper with a circular net type paper machine. The obtained web had a basis weight of 50 g / m ² .

Next, the web was bonded from both sides with a polyethylene film having a thickness of 25 μm as the center to prepare a bonded sheet material having a basis weight of 123 g / m ² and a thickness of 180 μm. Subsequently, a dehumidifying sheet of Comparative Example 16 was prepared by impregnating a mixed aqueous solution of guanidine sulfamate having a concentration of 15% by mass and magnesium chloride having a concentration of 5% by mass. The content of guanidine sulfamate (hygroscopic salt) was 12% by mass and the content of magnesium chloride (hygroscopic salt) was 4% by mass with respect to the sheet material for dehumidification.

The obtained sheet material for dehumidification was subjected to corrugation (step height: 1.9 mm, pitch: 3.2 mm) to prepare a dehumidifying filter material of Comparative Example 16 having a columnar shape of 10 cmφ and length of 100 mm.

[Evaluation 3: Moisture adsorption test]
The dehumidifying sheets of Examples 10 to 17 and Comparative Examples 9 to 16 were cut into 10 cm × 10 cm, dried at 90 ° C. for 2 hours, and the dry mass W _SD was measured. Next, it was allowed to stand at 25 ° C. and a relative humidity of 30% (low humidity atmosphere) for 2 hours, and the mass WS ₃₀ was measured. Subsequently, with the temperature kept at 25 ° C., the relative humidity was raised to 50% (medium humidity atmosphere) and left for 2 hours, and the mass _WS50 was measured. Furthermore, with the temperature kept at 25 ° C., the relative humidity was raised to 90% (high humidity atmosphere) and left for 2 hours, and the mass _WS90 was measured. The water adsorption amounts A _S30 , A _S50 , A _S90 (%) were measured from the following formulas (5) to (7), and the results are shown in Table 2.
A _S30 (%) = (W _S30 −W _SD ) / W _SD × 100 (5)
A _S50 (%) = (W _S50 −W _SD ) / W _SD × 100 (6)
A _S90 (%) = (W _S90 −W _SD ) / W _SD × 100 (7)

[Evaluation 4: Moisture absorption / desorption test of filter material for dehumidification]
FIG. 1 shows a schematic cross-sectional view of a moisture adsorption / desorption test apparatus. A stainless steel tube 2 (inner diameter: 10 cm, length 30 cm) is attached to the upstream side of the stainless steel tube 1 (inner diameter: 10 cm, length 10 cm) filled with a dehumidifying filter material via an open / close valve 6. Further, a stainless steel tube 3 (inner diameter: 10 cm, length: 30 cm) is attached to the downstream side via an on-off valve 7. Temperature and humidity meters 4 and 5 are inserted in the stainless steel pipe 2 and the stainless steel pipe 3 respectively, so that the temperature and humidity of air (upstream side) and air (downstream side) can be measured.

Measurement of moisture desorption amount: The moisture absorption and desorption measuring device was placed in a variable temperature and humidity chamber adjusted to 25 ° C. and relative humidity 70%, the open / close valves 6 and 7 were opened, and air heated to 43 ° C. from the stainless tube 2 Is blown for 5 minutes at a downstream side air volume of 2 m / sec to desorb moisture from the dehumidifying filter material. From the temperature and humidity measured by the thermohygrometer 5, the moisture desorption amounts after 2 minutes and 5 minutes from the start of heated air blowing were obtained by time integration.

Measurement of moisture adsorption amount: Subsequently, the on-off valves 6 and 7 are closed and left for 15 minutes to cool the dehumidifying filter material to 25 ° C., then the on-off valves 6 and 7 are opened, Air at 25 ° C. and a relative humidity of 70% is blown for 6 minutes at an air flow rate of 2 m / sec on the downstream side surface to adsorb moisture to the filter material for dehumidification. From the temperature and humidity measured with the thermohygrometer 5, the moisture adsorption amount after 2 minutes and 5 minutes after the start of air blowing was obtained by time integration.

The measurement of the moisture adsorption / desorption amount was repeated 4 times, and the average values of the third and fourth times when the values were stabilized were converted into percentages with respect to the sheet material for dehumidification, and are shown in Table 2.

Dehumidifying sheet material of Examples 10 to 17 containing an amorphous moisture adsorbent and a hygroscopic salt as compared with the dehumidifying sheet material of Comparative Example 9 containing only the amorphous moisture adsorbent. Improved the moisture absorption in all high, medium and low humidity atmospheres. On the other hand, as can be seen from Comparative Examples 10 and 11, even when the dehumidifying sheet-like material containing silica gel contained a hygroscopic salt, the moisture adsorption amount hardly changed. As can be seen from Comparative Examples 12 and 13, even when the dehumidifying sheet-like material containing zeolite contained a hygroscopic salt, the moisture adsorption amount increased only slightly. As can be seen from Comparative Examples 14 and 15, when the dehumidifying sheet containing mesoporous silica contained a hygroscopic salt, the amount of moisture adsorbed decreased.

Compared with the dehumidifying filter material of Comparative Example 9 containing only the amorphous water adsorbent, the dehumidifying filter materials of Examples 10 to 17 containing the amorphous water adsorbent and the hygroscopic salt were: The amount of moisture adsorption and moisture desorption was improved. Further, the moisture desorption rate (moisture desorption rate (%) = 2 minutes after water desorption amount / 5 minutes water desorption amount × 100) was 50% in the dehumidifying filter material of Comparative Example 9, but Examples 10 to In the dehumidifying filter material of No. 17, it was 73 to 83%, and it was confirmed that moisture was quickly desorbed by regeneration at a low temperature of 43 ° C.

On the other hand, as can be seen from Comparative Examples 10 and 11, when the filter material for dehumidification containing silica gel contains a hygroscopic salt, the amount of moisture adsorbed after 5 minutes decreases, and the amount of moisture desorption changes little. There wasn't. As can be seen from Comparative Examples 12 and 13, the dehumidifying filter material containing zeolite did not show the influence of the hygroscopic salt in both the moisture adsorption amount and the moisture adsorption amount. As can be seen from Comparative Examples 14 and 15, when the dehumidifying filter material containing mesoporous silica contained a hygroscopic salt, the moisture adsorption amount decreased. Further, the moisture desorption rate is 60% in the dehumidifying filter material of Comparative Example 14, but 43% in the dehumidifying filter material of Comparative Example 15, and in the case of the dehumidifying filter material containing mesoporous silica. It was confirmed that moisture was difficult to desorb due to the hygroscopic salt.

The sheet material for dehumidification of Comparative Example 16 containing only the hygroscopic salt adsorbs a slight amount of water, but the dehumidifying filter material has a low moisture absorption / desorption amount, and was not at a level that can be used for a desiccant air conditioner. .

As described above, it was confirmed that the sheet materials for dehumidification of Examples 10 to 17 exhibited an excellent moisture adsorption amount in a low humidity atmosphere that was difficult to improve. In addition, it was confirmed that the dehumidifying filter materials of Examples 10 to 17 showed an excellent water adsorption / desorption amount at a regeneration temperature in a low temperature range (40 ° C. to less than 80 ° C.), which was difficult to improve. From this result, the dehumidifying sheet and the dehumidifying filter material of the present invention are either a known adsorbent alone (Comparative Examples 9, 10, 12, 14) or a porous moisture adsorbent carrying a hygroscopic salt ( It is clear that the dehumidifying sheet and the dehumidifying filter material using Comparative Examples 11, 13, 15, and 16) have surprisingly excellent effects in all high, medium, and low humidity atmospheres that cannot be predicted from the dehumidifying filter material. It is.

<Synthesis of Amorphous Hygroscopic Agent 1>
By the same method as the synthesis of the amorphous moisture adsorbent 1, an amorphous moisture absorbent 1 was obtained. This was confirmed to have the same properties as the amorphous water adsorbent 1.

<Synthesis of Amorphous Hygroscopic Agent 2>
Amorphous moisture absorbent 2 was obtained by the same method as the synthesis of amorphous moisture adsorbent 2. This was confirmed to have the same properties as the amorphous water adsorbent 2.

(Example 18)
Using the amorphous hygroscopic agent 1, a coating liquid (solid content concentration of 60. 5) containing the amorphous hygroscopic agent and water glass (sodium silicate) as a water-soluble silicate in the following configuration (in terms of dry mass). 00% by mass). Content of water-soluble silicate is 20.00 mass% with respect to the sum total (100 mass%) of an amorphous moisture absorbent and water-soluble silicate.
Amorphous hygroscopic agent 1 80.00% by mass
Water glass (sodium silicate) 20.00% by mass

Alumina / silica fiber paper (basis weight 240.0 g / m ² ) was prepared as a sheet base material, impregnated in the coating solution prepared above, dried and finished in a flat format. The dry coating amount of the coating liquid on the sheet substrate was 60.0 g / m ² . The finished flat sheets were laminated and placed in an electric furnace having an in-furnace temperature (firing temperature) of 900 ° C. and baked for 1 hour to produce the moisture-absorbing / releasing sheet of the present invention. Further, the finished moisture-absorbing / releasing sheet of the present invention is cut and cut into a predetermined size, and then combined into an aluminum frame and incorporated into an aluminum frame, and the shape of the opening of the honeycomb-shaped honeycomb according to the present invention is a parallelogram. A wet structure was made.

Example 19
Except for changing the furnace temperature to 850 ° C., a moisture absorbing / releasing sheet of the present invention and a moisture absorbing / releasing structure using the moisture absorbing / releasing sheet were produced in the same manner as in Example 18.

(Example 20)
Except for changing the furnace temperature to 400 ° C., a moisture absorbing / releasing sheet of the present invention and a moisture absorbing / releasing structure using the moisture absorbing / releasing sheet were produced in the same manner as in Example 18.

(Example 21)
A hygroscopic sheet of the present invention was produced in the same manner as in Example 18 except that the composition of the coating liquid was changed as follows, and a hygroscopic structure of the present invention was produced. Content of water-soluble silicate is 0.94 mass% with respect to the sum total of an amorphous moisture absorbent and water-soluble silicate.
Amorphous hygroscopic agent 1 99.06% by mass
Water glass (sodium silicate) 0.94 mass%

(Example 22)
A hygroscopic sheet of the present invention was produced in the same manner as in Example 18 except that the composition of the coating liquid was changed as follows, and a hygroscopic structure of the present invention was produced. Content of water-soluble silicate is 0.99 mass% with respect to the sum total of an amorphous moisture absorbent and water-soluble silicate.
Amorphous moisture absorbent 1 99.01% by mass
Water glass (sodium silicate) 0.99 mass%

(Example 23)
A hygroscopic sheet of the present invention was produced in the same manner as in Example 18 except that the composition of the coating liquid was changed as follows, and a hygroscopic structure of the present invention was produced. Content of water-soluble silicate is 1.86 mass% with respect to the sum total of an amorphous moisture absorbent and water-soluble silicate.
Amorphous hygroscopic agent 1 98.14% by mass
Water glass (sodium silicate) 1.86% by mass

(Example 24)
A hygroscopic sheet of the present invention was produced in the same manner as in Example 18 except that the composition of the coating liquid was changed as follows, and a hygroscopic structure of the present invention was produced. Content of water-soluble silicate is 1.96 mass% with respect to the sum total of an amorphous moisture absorbent and water-soluble silicate.
Amorphous moisture absorbent 1 98.04 mass%
Water glass (sodium silicate) 1.96 mass%

(Example 25)
A hygroscopic sheet of the present invention was produced in the same manner as in Example 18 except that the composition of the coating liquid was changed as follows, and a hygroscopic structure of the present invention was produced. Content of water-soluble silicate is 28.57 mass% with respect to the sum total of an amorphous moisture absorbent and water-soluble silicate.
Amorphous hygroscopic agent 71.43% by mass
Water glass (sodium silicate) 28.57 mass%

(Example 26)
A hygroscopic sheet of the present invention was produced in the same manner as in Example 18 except that the composition of the coating liquid was changed as follows, and a hygroscopic structure of the present invention was produced. Content of water-soluble silicate is 29.58 mass% with respect to the sum total of an amorphous moisture absorbent and water-soluble silicate.
Amorphous hygroscopic agent 70.42% by mass
Water glass (sodium silicate) 29.58% by mass

(Example 27)
A hygroscopic sheet of the present invention was produced in the same manner as in Example 18 except that the composition of the coating liquid was changed as follows, and a hygroscopic structure of the present invention was produced. Content of water-soluble silicate is 32.20 mass% with respect to the sum total of an amorphous moisture absorbent and water-soluble silicate.
Amorphous hygroscopic agent 1 67.80% by mass
Water glass (sodium silicate) 32.20% by mass

(Example 28)
A hygroscopic sheet of the present invention was produced in the same manner as in Example 18 except that the composition of the coating liquid was changed as follows, and a hygroscopic structure of the present invention was produced. Content of water-soluble silicate is 33.34 mass% with respect to the sum total of an amorphous moisture absorbent and water-soluble silicate.
Amorphous moisture absorbent 1 66.66 mass%
Water glass (sodium silicate) 33.34% by mass

(Example 29)
A hygroscopic sheet of the present invention was produced in the same manner as in Example 18 except that the amorphous hygroscopic agent was changed to the amorphous hygroscopic agent 2, and the hygroscopic structure of the present invention was produced.

(Example 30)
The hygroscopic property of the present invention is the same as in Example 18 except that the solid content concentration of the coating liquid is 20.00% by mass and the dry coating amount of the coating liquid on the sheet substrate is 5.0 g / m ^2. A sheet was produced to produce a moisture absorbing / releasing structure according to the present invention.

(Example 31)
The same as in Example 18 except that the solid content concentration of the coating liquid was 20.00% by mass, the impregnation time was adjusted, and the dry coating amount of the coating liquid on the sheet substrate was 4.7 g / m ^2. Thus, the hygroscopic sheet of the present invention was produced, and the hygroscopic structure of the present invention was produced.

(Example 32)
After drying the moisture-absorbing / releasing sheet of the present invention produced in Example 18, the coating liquid was impregnated and dried again in the same manner, and the coating amount of the coating liquid on the sheet substrate was 100.0 g / m ^2. A hygroscopic sheet of the present invention was produced in the same manner as in Example 18 except that the hygroscopic structure of the present invention was produced.

(Example 33)
In Example 32, the same procedure as in Example 32 was performed except that, during the second impregnation treatment, the impregnation time was adjusted so that the dry coating amount of the coating liquid on the sheet substrate was 105.0 g / m ^2. The moisture absorbing / releasing sheet of the invention was prepared, and the moisture absorbing / releasing structure of the present invention was prepared.

(Example 34)
After immersing the hygroscopic structure of the present invention produced in Example 18 in a lithium chloride aqueous solution (solid concentration: 5.00% by mass) for 30 seconds, it was pulled up and dried with a dryer (set temperature: 60 ° C.). Thus, a hygroscopic structure having a hygroscopic salt supported on the surface of the present invention was obtained.

(Example 35)
A hygroscopic structure having a hygroscopic salt supported on the surface of the present invention was obtained in the same manner as in Example 34 except that the lithium chloride aqueous solution was changed to a magnesium chloride aqueous solution (solid concentration: 5.00% by mass). .

(Comparative Example 17)
A hygroscopic sheet was produced in the same manner as in Example 18 except that the composition of the coating liquid was changed as follows to produce a hygroscopic structure.
Amorphous hygroscopic agent 1 100.00% by mass

(Comparative Example 18)
A hygroscopic sheet was produced in the same manner as in Example 18 except that the water-soluble silicate was changed to alumina sol as an inorganic binder, and a hygroscopic structure was produced.

(Comparative Example 19)
A hygroscopic sheet was produced in the same manner as in Example 18 except that the firing temperature was changed to 945 ° C., and a hygroscopic structure was produced.

(Comparative Example 20)
A hygroscopic sheet was produced in the same manner as in Example 18 except that the amorphous hygroscopic agent 1 was changed to zeolite powder, and a hygroscopic structure was produced.

(Example 36)
Using amorphous hygroscopic agent 1, a papermaking slurry (solid content concentration: 1.20% by mass) was prepared in the following configuration (in terms of dry mass). The water-soluble silicate is contained in an amount of 20.01% by mass with respect to the total amount of the amorphous hygroscopic agent and the water-soluble silicate, and the fibrous material contains the amorphous hygroscopic agent and the water-soluble silicate. And 44.44 mass% is contained with respect to the sum total (100 mass%) with a fibrous material.
Amorphous moisture absorbent 1 44.44% by mass
Water glass (sodium silicate) 11.12% by mass
Fibrous material (alumina / silica) 44.44% by mass

A handsheet having a basis weight of 120 g / m ² was prepared using the obtained slurry. The produced handsheets were stacked and placed in an electric furnace having an in-furnace temperature of 900 ° C. and fired for 1 hour to produce the moisture-absorbing / releasing sheet of the present invention. The finished moisture-absorbing / releasing sheet of the present invention is cut into a predetermined size, cut into pieces, and then combined into an aluminum frame and incorporated into an aluminum frame, and the shape of the opening of the honeycomb-shaped moisture-absorbing / releasing structure of the present invention is a parallelogram The body was made.

(Example 37)
A hygroscopic sheet and a hygroscopic structure of the present invention were produced in the same manner as in Example 36 except that the construction of the papermaking slurry was changed as follows. The water-soluble silicate is contained in an amount of 20.01% by mass with respect to the total of the amorphous moisture-absorbing agent and the water-soluble silicate, and the fibrous material includes the amorphous moisture-absorbing agent, the water-soluble silicate, And 27.54% by mass with respect to the total of the fibrous materials.
Amorphous hygroscopic agent 1 57.97% by mass
Water glass (sodium silicate) 14.49% by mass
Ceramic fiber (alumina / silica) 27.54% by mass

(Example 38)
A hygroscopic sheet and a hygroscopic structure of the present invention were produced in the same manner as in Example 36 except that the construction of the papermaking slurry was changed as follows. The water-soluble silicate is contained in an amount of 20.01% by mass with respect to the total of the amorphous moisture-absorbing agent and the water-soluble silicate, and the fibrous material includes the amorphous moisture-absorbing agent, the water-soluble silicate, And 28.57% by mass based on the total of the fibrous materials.
Amorphous moisture absorbent 1 57.14% by mass
Water glass (sodium silicate) 14.29% by mass
Ceramic fiber (alumina / silica) 28.57% by mass

(Example 39)
A hygroscopic sheet and a hygroscopic structure of the present invention were produced in the same manner as in Example 36 except that the construction of the papermaking slurry was changed as follows. The water-soluble silicate is contained in an amount of 20.00% by mass with respect to the total of the amorphous hygroscopic agent and the water-soluble silicate, and the fibrous material contains the amorphous hygroscopic agent, the water-soluble silicate, And 54.55% by mass with respect to the total of the fibrous materials.
Amorphous moisture absorbent 1 36.36% by mass
Water glass (sodium silicate) 9.09 mass%
Ceramic fiber (alumina / silica) 54.55% by mass

(Example 40)
A hygroscopic sheet and a hygroscopic structure of the present invention were produced in the same manner as in Example 36 except that the construction of the papermaking slurry was changed as follows. The water-soluble silicate is contained 19.99% by mass with respect to the total of the amorphous moisture-absorbing agent and the water-soluble silicate, and the fibrous material contains the amorphous moisture-absorbing agent, the water-soluble silicate, And 55.83% by mass with respect to the total of the fibrous materials.
Amorphous moisture absorbent 1 35.34% by mass
Water glass (sodium silicate) 8.83 mass%
Ceramic fiber (alumina / silica) 55.83% by mass

(Example 41)
A hygroscopic sheet and a hygroscopic structure of the present invention were produced in the same manner as in Example 36 except that the construction of the papermaking slurry was changed as follows. The water-soluble silicate is contained in an amount of 19.98% by mass with respect to the total of the amorphous moisture-absorbing agent and the water-soluble silicate, and the fibrous material includes the amorphous moisture-absorbing agent, the water-soluble silicate, And 60.32% by mass with respect to the total of the fibrous materials.
Amorphous moisture absorbent 1 31.75% by mass
Water glass (sodium silicate) 7.93 mass%
Ceramic fiber (alumina / silica) 60.32% by mass

(Example 42)
A hygroscopic sheet and a hygroscopic structure of the present invention were produced in the same manner as in Example 36 except that the configuration of the papermaking slurry was changed as follows. The water-soluble silicate is contained 19.99% by mass with respect to the total of the amorphous moisture-absorbing agent and the water-soluble silicate, and the fibrous material contains the amorphous moisture-absorbing agent, the water-soluble silicate, , 61.54% by mass with respect to the total of the fibrous materials.
Amorphous moisture absorbent 1 30.77 mass%
Water glass (sodium silicate) 7.69 mass%
Ceramic fiber (alumina / silica) 61.54% by mass

(Example 43)
A hygroscopic structure having a hygroscopic salt supported on the surface of the present invention was obtained in the same manner as in Example 34 except that the hygroscopic structure of the present invention was changed to that prepared in Example 36. .

(Example 44)
A hygroscopic structure having a hygroscopic salt supported on the surface of the present invention was obtained in the same manner as in Example 35 except that the hygroscopic structure of the present invention was changed to that prepared in Example 36. .

(Comparative Example 21)
A hygroscopic sheet was produced in the same manner as in Example 36 except that the composition of the coating liquid was changed as follows to produce a hygroscopic structure.
Amorphous hygroscopic agent 1 50.00% by mass
Ceramic fiber (alumina / silica) 50.00% by mass

(Comparative Example 622)
A hygroscopic sheet was produced in the same manner as in Example 36 except that the water-soluble silicate was changed to alumina sol as an inorganic binder, and a hygroscopic structure was produced.

(Comparative Example 23)
A hygroscopic sheet was produced in the same manner as in Example 36 except that the firing temperature was changed to 945 ° C., and a hygroscopic structure was produced.

(Comparative Example 24)
A hygroscopic sheet was produced in the same manner as in Example 36 except that the amorphous hygroscopic agent 1 was changed to zeolite powder, and a hygroscopic structure was produced.

(Example 45)
Alumina-silica fiber paper (basis weight 240.0 g / m ² ) was prepared as a sheet base material, impregnated in the coating liquid prepared in Example 18, dried and wound up. Content of water-soluble silicate is 20.00 mass% with respect to the sum total of an amorphous moisture absorbent and water-soluble silicate. The dry coating amount of the coating liquid on the sheet substrate was 60.0 g / m ² . During drying, a part of the sheet was passed through a corrugated roll heated to 200 ° C. to obtain a corrugated sheet, which was also wound up. The produced flat sheet and corrugated sheet were laminated, and the joined portion was joined using alumina sol as a binder to produce a honeycomb structure. The structure was put in an electric furnace, heated at a preset temperature of 900 ° C., and kept at the preset temperature of 900 ° C. for 1 hour to carry out a firing treatment to produce a moisture absorbing / releasing structure of the present invention.

(Example 46)
A hygroscopic structure of the present invention was produced in the same manner as in Example 45 except that the coating liquid was changed to the coating liquid produced in Example 21. Content of water-soluble silicate is 0.94 mass% with respect to the sum total of an amorphous moisture absorbent and water-soluble silicate.

(Example 47)
A hygroscopic structure of the present invention was produced in the same manner as in Example 45 except that the coating liquid was changed to the coating liquid produced in Example 22. Content of water-soluble silicate is 0.99 mass% with respect to the sum total of an amorphous moisture absorbent and water-soluble silicate.

(Example 48)
A hygroscopic structure of the present invention was produced in the same manner as in Example 45 except that the coating liquid was changed to the coating liquid produced in Example 23. Content of water-soluble silicate is 1.86 mass% with respect to the sum total of an amorphous moisture absorbent and water-soluble silicate.

(Example 49)
A hygroscopic structure of the present invention was produced in the same manner as in Example 45 except that the coating liquid was changed to the coating liquid produced in Example 24. Content of water-soluble silicate is 1.96 mass% with respect to the sum total of an amorphous moisture absorbent and water-soluble silicate.

(Example 50)
A hygroscopic structure of the present invention was produced in the same manner as in Example 45 except that the coating liquid was changed to the coating liquid produced in Example 825. Content of water-soluble silicate is 28.57 mass% with respect to the sum total of an amorphous moisture absorbent and water-soluble silicate.

(Example 51)
A hygroscopic structure of the present invention was produced in the same manner as in Example 45 except that the coating liquid was changed to the coating liquid produced in Example 9. Content of water-soluble silicate is 29.58 mass% with respect to the sum total of an amorphous moisture absorbent and water-soluble silicate.

(Example 52)
A hygroscopic structure of the present invention was produced in the same manner as in Example 45 except that the coating liquid was changed to the coating liquid produced in Example 27. Content of water-soluble silicate is 32.20 mass% with respect to the sum total of an amorphous moisture absorbent and water-soluble silicate.

(Example 53)
A hygroscopic structure of the present invention was produced in the same manner as in Example 45 except that the coating liquid was changed to the coating liquid produced in Example 28. Content of water-soluble silicate is 33.34 mass% with respect to the sum total of an amorphous moisture absorbent and water-soluble silicate.

(Example 54)
A hygroscopic structure of the present invention was produced in the same manner as in Example 45 except that the amorphous moisture absorbent was changed to the amorphous moisture absorbent 2.

(Example 55)
The hygroscopic property of the present invention is the same as in Example 45 except that the solid content concentration of the coating liquid is 20.00% by mass and the dry coating amount of the coating liquid on the sheet substrate is 5.0 g / m ^2. A structure was produced.

(Example 56)
The same as in Example 45 except that the solid content concentration of the coating liquid was 20.00% by mass, the impregnation time was adjusted, and the dry coating amount of the coating liquid on the sheet substrate was 4.7 g / m ^2. Thus, a hygroscopic structure of the present invention was produced.

(Example 57)
After drying the sheet prepared in Example 45, the coating liquid was again impregnated in the same manner, dried and wound up, except that the dry coating amount of the coating liquid on the sheet substrate was 100.0 g / m ^2. Produced a moisture absorbing / releasing structure of the present invention in the same manner as in Example 45. However, when the sheet was produced, the corrugated sheet was processed during the second impregnation treatment.

(Example 58)
In Example 57, the same procedure as in Example 57 was performed except that, during the second impregnation treatment, the impregnation time was adjusted so that the dry coating amount of the coating liquid on the sheet substrate was 105.0 g / m ^2. The moisture absorbing / releasing structure of the invention was prepared.

(Example 59)
Except for changing the hygroscopic structure of the present invention to that prepared in Example 45, a hygroscopic structure having a hygroscopic salt supported on the surface of the present invention was obtained in the same manner as in Example 17. .

(Example 60)
Except for changing the hygroscopic structure of the present invention to that produced in Example 45, a hygroscopic structure having a hygroscopic salt supported on the surface of the present invention was obtained in the same manner as in Example 35. .

(Comparative Example 25)
A moisture absorbing / releasing structure was prepared in the same manner as in Example 45 except that the coating liquid was changed to the coating liquid prepared in Comparative Example 17.

(Comparative Example 26)
A hygroscopic structure was produced in the same manner as in Example 45 except that the water-soluble silicate was changed to alumina sol as an inorganic binder.

(Comparative Example 27)
A hygroscopic structure was produced in the same manner as in Example 45 except that the firing temperature was changed to 945 ° C.

(Comparative Example 28)
A hygroscopic structure was prepared in the same manner as in Example 45 except that the coating liquid was changed to the coating liquid prepared in Comparative Example 20.

(Example 61)
The honeycomb-like structure made of aluminum was impregnated with the coating liquid produced in Example 18 for 1 minute, then pulled up and dried at room temperature for 24 hours. The content of the water-soluble silicate is 25.00% by mass with respect to the amorphous hygroscopic agent. The honeycomb structure with the coating solution adhered to the surface is placed in an electric furnace, the furnace temperature (firing temperature) is set to 600 ° C., and the set temperature is maintained at 600 ° C. for 1 hour. Then, the moisture absorbing / releasing structure of the present invention was obtained.

(Example 62)
A hygroscopic structure of the present invention was obtained in the same manner as in Example 61 except that the honeycomb structure was changed to an alumina honeycomb structure and the firing temperature was changed to 900 ° C.

(Example 63)
The moisture absorbing / releasing structure of the present invention was obtained in the same manner as in Example 61 except that the honeycomb structure was changed to a non-combustible glass paper honeycomb processed product and the firing temperature was changed to 500 ° C.

(Example 64)
A hygroscopic structure of the present invention was produced in the same manner as in Example 63 except that the coating liquid was changed to the coating liquid produced in Example 21. Content of water-soluble silicate is 0.94 mass% with respect to the sum total of an amorphous moisture absorbent and water-soluble silicate.

(Example 65)
A hygroscopic structure of the present invention was produced in the same manner as in Example 63 except that the coating liquid was changed to the coating liquid produced in Example 22. Content of water-soluble silicate is 0.99 mass% with respect to the sum total of an amorphous moisture absorbent and water-soluble silicate.

Example 66
A hygroscopic structure of the present invention was produced in the same manner as in Example 63 except that the coating liquid was changed to the coating liquid produced in Example 23. Content of water-soluble silicate is 1.86 mass% with respect to the sum total of an amorphous moisture absorbent and water-soluble silicate.

(Example 67)
A hygroscopic structure of the present invention was produced in the same manner as in Example 63 except that the coating liquid was changed to the coating liquid produced in Example 24. Content of water-soluble silicate is 1.96 mass% with respect to the sum total of an amorphous moisture absorbent and water-soluble silicate.

Example 68
A hygroscopic structure of the present invention was produced in the same manner as in Example 63 except that the coating liquid was changed to the coating liquid produced in Example 25. Content of water-soluble silicate is 28.57 mass% with respect to the sum total of an amorphous moisture absorbent and water-soluble silicate.

(Example 69)
A hygroscopic structure of the present invention was produced in the same manner as in Example 63 except that the coating liquid was changed to the coating liquid produced in Example 26. Content of water-soluble silicate is 29.58 mass% with respect to the sum total of an amorphous moisture absorbent and water-soluble silicate.

(Example 70)
A hygroscopic structure of the present invention was produced in the same manner as in Example 63 except that the coating liquid was changed to the coating liquid produced in Example 27. Content of water-soluble silicate is 32.20 mass% with respect to the sum total of an amorphous moisture absorbent and water-soluble silicate.

(Example 71)
A moisture absorbing / releasing structure of the present invention was produced in the same manner as in Example 63 except that the coating liquid was changed to the coating liquid produced in Example 28. Content of water-soluble silicate is 33.34 mass% with respect to the sum total of an amorphous moisture absorbent and water-soluble silicate.

(Example 72)
A hygroscopic structure of the present invention was produced in the same manner as in Example 63 except that the amorphous moisture absorbent was changed to the amorphous moisture absorbent 2.

(Example 73)
The hygroscopic structure of the present invention was changed to that produced in Example 63, and a hygroscopic salt was supported on the surface of the present invention in the same manner as in Example 34 except that the firing temperature was 500 ° C. A hygroscopic structure was obtained.

(Example 74)
The hygroscopic structure of the present invention was changed to that produced in Example 63, and a hygroscopic salt was supported on the surface of the present invention in the same manner as in Example 35 except that the firing temperature was 500 ° C. A hygroscopic structure was obtained.

(Comparative Example 29)
A hygroscopic structure was produced in the same manner as in Example 63 except that the coating liquid was changed to the coating liquid prepared in Comparative Example 17.

(Comparative Example 30)
A hygroscopic structure was produced in the same manner as in Example 63 except that the water-soluble silicate was changed to alumina sol which is an inorganic binder.

(Comparative Example 31)
A hygroscopic structure was prepared in the same manner as in Example 63 except that the coating liquid was changed to the coating liquid prepared in Comparative Example 21.

(Evaluation of powder removal)
The hygroscopic sheets produced in Examples 18 to 44 and Comparative Examples 17 to 25 were cut to 5 cm × 20 cm, and a 5 cm square 200 g weight was placed on one end in the long side direction. The sheet on which this weight was placed was pulled on the black paper at a speed of 10 cm / second, and the detached moisture absorbent remaining on the black paper was observed, and the state was evaluated in the following stages.
◎: No moisture absorbent on black paper ○: Slight moisture absorbent on black paper △: Very fine moisture absorbent on black paper ×: Coarse-grained moisture absorbent on black paper Remaining state

(Evaluation of powder removal due to thermal deterioration)
The hygroscopic sheets prepared in Examples 18 to 44 and Comparative Examples 17 to 25 are cut to 5 cm × 20 cm, put into an electric furnace having a furnace temperature of 300 ° C., taken out after 1 minute, and rapidly cooled at room temperature. . Repeat the same operation 5 times. After this operation, the state of the detached hygroscopic agent remaining on the black paper was evaluated in the same manner as in the above “evaluation of powder falling off”.

(Hygroscopic evaluation)
In the moisture absorbing / releasing structure produced in Examples and Comparative Examples, the moisture absorbing / releasing structure having an outside dimension adjusted so that the surface area of the moisture absorbing / releasing structure contacting the circulating air is the same in calculation, has an inner diameter of 9 cm. Placed in a glass tube. Next, heated air having a temperature of 40 ° C. and a relative humidity of 45% was sent into the glass tube to adjust the hygroscopic structure to an initial dehydrated state. Thereafter, air having a saturated water content (25 ° C., relative humidity of 100%) that has sufficiently passed water at 25 ° C. from one end of the glass tube is allowed to flow at a flow rate of 200 ml / sec. The time until the relative humidity of the outflow side air exceeded 60% was measured while maintaining the outflowing air at 25 ° C. The higher the moisture absorption performance, the longer this time.

(Evaluation of hygroscopic thermal degradation)
The hygroscopic structures produced in Examples and Comparative Examples having the same external dimensions as those used in “Evaluation of hygroscopicity” were put into an electric furnace having a furnace temperature of 300 ° C., taken out after 1 minute, and at room temperature. Cool quickly. The same operation is repeated at room temperature for a total of 5 times. After this operation, the hygroscopic property is evaluated in the same manner as the “evaluation of hygroscopic property”.

(Evaluation of moisture release)
In the moisture absorbing / releasing structure produced in Examples and Comparative Examples, the moisture absorbing / releasing structure having an outside dimension adjusted so that the surface area of the moisture absorbing / releasing structure contacting the circulating air is the same in calculation, has an inner diameter of 9 cm. Placed in a glass tube. Air at a temperature of 25 ° C. and a relative humidity of 100% was flowed at a flow rate of 200 ml / second for 10 minutes to adjust the initial moisture absorption state. After this, heated air of 40 ° C and 45% relative humidity is introduced at a flow rate of 200 ml / second from one end of the glass tube, and the relative humidity at the beginning of the outflow is measured while maintaining the air flowing out of the glass tube at 45 ° C. did. The fact that the relative humidity at the beginning of the outflow is high indicates that it has a capability of quickly releasing moisture in a low temperature drying of 40 ° C.

(Moisture release is also evaluated for thermal degradation)
The moisture-absorbing / releasing structures produced in the examples and comparative examples having the same external dimensions as those used in “Evaluation of moisture-releasing” are put into an electric furnace having a furnace temperature of 300 ° C., taken out after 1 minute, and at room temperature. Cool quickly. Repeat the same operation 5 times. After this operation, the moisture release property is evaluated in the same manner as the “evaluation of moisture release”.

(Evaluation of moisture absorption rate)
The mass W1 after the moisture absorbing / releasing structures produced in Examples and Comparative Examples were allowed to stand for 5 hours in air at 23 ° C. and 70% relative humidity was measured. Further, the moisture absorbing / releasing structure after moisture absorption was dehydrated with an oven at 85 ° C. for 2 hours, and then the mass W2 was measured immediately. The moisture absorption rate was calculated from equation (8).
Moisture absorption rate = (W1-W2) / W2 × 100 (8)

Tables 3 to 6 show the evaluation results obtained in each example and each comparative example.

From the evaluation results of the powder-off property and the powder-off property due to thermal deterioration shown in Tables 3 to 6, the moisture-absorbing / releasing sheet and the moisture-absorbing / releasing structure of the present invention show no powder falling off from the surface. Further, it is clear that the strength characteristics are not deteriorated even by a plurality of heat treatments, and no powder falling occurs. Furthermore, it can be seen that the moisture absorbing / releasing structure of the present invention is excellent both in terms of moisture absorption and moisture releasing, with no deterioration due to the effect of heat treatment.
On the other hand, the moisture absorbing / releasing sheet and moisture absorbing / releasing structure of the comparative example generate powder falling and clearly show deterioration of strength characteristics due to heat treatment. In addition, the hygroscopic sheet and the hygroscopic structure of the comparative example are particularly deteriorated in hygroscopic performance, suggesting the possibility of being unable to withstand actual use. As shown in Comparative Example 31, when the baking treatment is performed at a temperature exceeding 920 ° C., powder fall does not occur, but it is possible to confirm the deterioration of hygroscopicity and release property, and the deterioration due to the heat treatment.

It can be seen that the moisture-absorbing / releasing sheet and moisture-absorbing / absorbing structure of the example have a moisture absorption rate, that is, a capacity of moisture that can be absorbed, by supporting the moisture-absorbing salt.
As described above, it is clear that the moisture absorption rate is improved while maintaining good hygroscopicity and good moisture desorption properties, and the hygroscopic sheet and hygroscopic structure of the present invention are excellent. .

<Synthesis of amorphous adsorbent>
An amorphous adsorbent was obtained by the same method as the synthesis of the amorphous water adsorbent 1. This was confirmed to have the same properties as the amorphous water adsorbent 1.

Example 75
<Preparation of adsorbent coating solution>
A horizontal wet disperser dyno mill (Shinmaru Enterprises) in which 500 parts by mass of an amorphous adsorbent, 480 parts by mass of methanol, and 20 parts by mass of polyoxyethylene (10) octylphenyl ether were mixed and filled with 2 mmφ zirconia beads. To make an adsorbent dispersion.

Next, 100 parts by mass of N-methoxymethylated nylon (manufactured by Nagase Chemtech Co., Ltd., trade name: Toresin (registered trademark) F-30K, binder) and 900 parts of methanol are mixed together to obtain a binder solution. Got. To 1000 parts of the adsorbent dispersion, 319 parts by mass of the binder solution was added and mixed to obtain an adsorbent coating liquid. The mass ratio of the adsorbent / binder was 94/6, and the total concentration of the adsorbent and the binder with respect to the total amount of the adsorbent coating solution was 40% by mass.

<Preparation of coating liquid A for undercoat layer>
Mix 1.5 parts by weight of polyvinyl butyral (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name: 6000-C), 30 parts by weight of methanol, 55 parts by weight of 2-propanol, and 15 parts by weight of 1-butanol. A coating liquid A for the layering was prepared.

<Preparation of adsorption sheet>
A 25 μm aluminum foil was subjected to a single-stage corrugation process with a step height of 1.5 mm and a pitch of 2.4 mm, and this was rolled up into a cylindrical shape to produce a cylindrical aluminum honeycomb body having a diameter of 10 cm and a length of 10 cm. The aluminum honeycomb body was immersed in the undercoat layer coating liquid A, pulled up, and air was applied from above to blow off excess alcohol in the cylindrical shape. Then, it heated at 80 degreeC for 30 minutes, and produced the undercoat layer. Next, it was pulled up after being immersed in the adsorbent coating solution and heated at 80 ° C. for 1 hour to form an adsorbing layer, thereby producing a cylindrical filter. The amount of the adsorbent supported on the obtained cylindrical filter was 70 g / liter (cylindrical filter volume).

Examples 76-82
A cylindrical filter was produced in the same manner as in Example 75 except that the mass ratio of the adsorbent / binder was changed as shown in Table 17. Table 17 shows the amount of adsorbent supported on the obtained cylindrical filter.

Example 83
A glass fiber nonwoven fabric (manufactured by Oji Specialty Paper Co., Ltd.) of 20 g / m ² was bonded to both surfaces of a 20 μm thick polyethylene sheet by a laminating method to produce a 200 μm thick sheet base material. The adsorbent coating solution prepared in Example 175 was applied to both surfaces of the obtained sheet substrate, and then heated at 80 ° C. for 1 hour to produce an adsorption sheet. This adsorption sheet was processed in a single-stage corrugation with a step height of 1.9 mm and a pitch of 3.2 mm, and this was wound into a cylindrical shape to produce a cylindrical filter having a diameter of 10 cm and a length of 10 cm. The amount of adsorbent supported on the obtained cylindrical filter was 100 g / liter (cylindrical filter volume).

Example 84
A 25 g / m ² polyethylene terephthalate nonwoven fabric (manufactured by Mitsubishi Paper Industries Co., Ltd.) was bonded to both surfaces of a 20 μm thick polyethylene sheet by a laminating method to prepare a 160 μm thick sheet base material. The adsorbent coating solution prepared in Example 175 was applied to both surfaces of the obtained sheet substrate, and then heated at 80 ° C. for 1 hour to produce an adsorption sheet. The adsorption sheet here was processed in a single-stage corrugation with a step height of 1.9 mm and a pitch of 3.2 mm, and this was wound into a cylindrical shape to produce a cylindrical filter having a diameter of 10 cm and a length of 10 cm. The amount of adsorbent supported on the obtained cylindrical filter was 100 g / liter (cylindrical filter volume).

Example 85
<Preparation of adsorbent coating solution>
Horizontal type in which 500 parts by mass of an amorphous adsorbent, 480 parts by mass of N-methyl-2-pyrrolidone (NMP) and 20 parts by mass of polyoxyethylene (10) octylphenyl ether are mixed and filled with 2 mmφ zirconia beads. Dispersion was carried out with a wet disperser DYNOMILL (manufactured by Shinmaru Enterprises) to prepare an adsorbent dispersion.

Next, 100 parts by mass of vinylidene fluoride polymer (trade name: Kureha KF Polymer (registered trademark) 1120, manufactured by Kureha Co., Ltd., binder) and 900 parts of NMP are mixed to obtain a binder solution. It was. To 1000 parts of the adsorbent dispersion liquid, 317 parts by mass of the binder solution was added and mixed to obtain an adsorbent coating liquid. The mass ratio of the adsorbent / binder was 94/6, and the total concentration of the adsorbent and the binder with respect to the total amount of the adsorbent coating solution was 40% by mass.

A glass fiber nonwoven fabric (manufactured by Oji Specialty Paper Co., Ltd.) of 20 g / m ² was bonded to both surfaces of a 20 μm thick polyethylene sheet by a laminating method to produce a 200 μm thick sheet base material. The adsorbent coating solution was applied to both surfaces of the obtained sheet base material, and then heated at 80 ° C. for 1 hour to produce an adsorption sheet. This adsorption sheet was processed in a single-stage corrugation with a step height of 1.9 mm and a pitch of 3.2 mm, and this was wound into a cylindrical shape to produce a cylindrical filter having a diameter of 10 cm and a length of 10 cm. The amount of adsorbent supported on the obtained cylindrical filter was 90 g / liter (cylindrical filter volume).

Examples 86-93
A cylindrical filter was produced in the same manner as in Example 85 except that the mass ratio of the adsorbent / binder was changed as shown in Table 17. Table 7 shows the amount of adsorbent supported on the obtained cylindrical filter.

Example 94
<Preparation of adsorbent coating solution>
A horizontal wet disperser dyno mill (Shinmaru Enterprises) in which 500 parts by mass of an amorphous adsorbent, 480 parts by mass of methanol, and 20 parts by mass of polyoxyethylene (10) octylphenyl ether were mixed and filled with 2 mmφ zirconia beads. To make an adsorbent dispersion.

Next, 100 parts by mass of polyvinyl butyral (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name: 3000-K, binder) and 900 parts of methanol were mixed to obtain a binder solution. To 1000 parts of the adsorbent dispersion liquid, 247 parts by mass of the binder solution was added and mixed to obtain an adsorbent coating liquid. The mass ratio of the adsorbent / binder was 91/9, and the total concentration of the adsorbent and the binder relative to the total amount of the adsorbent coating liquid was 37% by mass.

<Preparation of adsorption sheet>
A 25 μm aluminum foil was subjected to a single-stage corrugation process with a step height of 1.5 mm and a pitch of 2.4 mm, and this was rolled up into a cylindrical shape to produce a cylindrical aluminum honeycomb body having a diameter of 10 cm and a length of 10 cm. The aluminum honeycomb body was immersed in the undercoat layer coating liquid A, pulled up, and air was applied from above to blow off excess alcohol in the cylindrical shape. Then, it heated at 80 degreeC for 30 minutes, and produced the undercoat layer. Next, it was pulled up after being immersed in the adsorbent coating solution and heated at 80 ° C. for 1 hour to form an adsorbing layer, thereby producing a cylindrical filter. The amount of the adsorbent supported on the obtained cylindrical filter was 70 g / liter (cylindrical filter volume).

Example 95
<Preparation of adsorbent coating solution>
A horizontal wet disperser in which 500 parts by mass of an amorphous adsorbent, 480 parts by mass of 1-methoxy-2-propanol and 20 parts by mass of polyoxyethylene (10) octylphenyl ether are mixed and filled with 2 mmφ zirconia beads. Dispersion was performed using a dyno mill (manufactured by Shinmaru Enterprises) to prepare an adsorbent dispersion.

Next, a copolymer (binder) having a mass average molecular weight of 40,000 obtained by copolymerizing 100 parts by mass of methyl methacrylate / n-butyl acrylate / methacrylic acid at a mass ratio of 4/4/2, and 900 parts of 1- Mixing with methoxy-2-propanol gave a binder solution. To 1000 parts of the adsorbent dispersion, 341 parts by mass of the binder solution was added and mixed to obtain an adsorbent coating liquid. The mass ratio of the adsorbent / binder was 88/12, and the total concentration of the adsorbent and the binder with respect to the total amount of the adsorbent coating solution was 34% by mass.

<Preparation of adsorption sheet>
A 25 μm aluminum foil was subjected to a single-stage corrugation process with a step height of 1.5 mm and a pitch of 2.4 mm, and this was rolled up into a cylindrical shape to produce a cylindrical aluminum honeycomb body having a diameter of 10 cm and a length of 10 cm. The aluminum honeycomb body was immersed in the undercoat layer coating liquid A, pulled up, and air was applied from above to blow off excess alcohol in the cylindrical shape. Then, it heated at 80 degreeC for 30 minutes, and produced the undercoat layer. Next, it was pulled up after being immersed in the adsorbent coating solution and heated at 80 ° C. for 1 hour to form an adsorbing layer, thereby producing a cylindrical filter. The amount of the adsorbent supported on the obtained cylindrical filter was 70 g / liter (cylindrical filter volume).

Example 96
The same method as in Example 95, except that a copolymer having a weight average molecular weight of 40,000 obtained by copolymerizing methyl methacrylate / n-butyl acrylate / methacrylic acid at a mass ratio of 4/3/3 was used as the binder. Thus, a cylindrical filter was produced. The amount of the adsorbent supported on the obtained cylindrical filter was 70 g / liter (cylindrical filter volume).

Comparative Example 32
<Preparation of adsorbent coating solution>
500 parts by mass of silica gel (trade name: silica gel A, specific surface area 700 m ² / g by BET method, manufactured by Toyoda Chemical Co., Ltd., adsorbent), 480 parts by mass of methanol, 20 parts by mass of polyoxyethylene (10) octylphenyl ether Were mixed with a horizontal wet disperser DYNOMILL (manufactured by Shinmaru Enterprises) filled with 2 mmφ zirconia beads to prepare an adsorbent dispersion.

Next, 100 parts by mass of N-methoxymethylated nylon (manufactured by Nagase Chemtech Co., Ltd., trade name: Toresin (registered trademark) F-30K, binder) and 900 parts of methanol are mixed together to obtain a binder solution. Got. To 1000 parts of the adsorbent dispersion liquid, 247 parts by mass of the binder solution was added and mixed to obtain an adsorbent coating liquid. The mass ratio of the adsorbent / binder was 91/9, and the total concentration of the adsorbent and the binder relative to the total amount of the adsorbent coating liquid was 37% by mass.

<Preparation of adsorption sheet>
A 25 μm aluminum foil was subjected to a single-stage corrugation process with a step height of 1.5 mm and a pitch of 2.4 mm, and this was rolled up into a cylindrical shape to produce a cylindrical aluminum honeycomb body having a diameter of 10 cm and a length of 10 cm. The aluminum honeycomb body was immersed in the undercoat layer coating liquid A, pulled up, and air was applied from above to blow off excess alcohol in the cylindrical shape. Then, it heated at 80 degreeC for 30 minutes, and produced the undercoat layer. Next, it was pulled up after being immersed in the adsorbent coating solution and heated at 80 ° C. for 1 hour to form an adsorbing layer, thereby producing a cylindrical filter. The amount of adsorbent supported on the obtained cylindrical filter was 80 g / liter (cylindrical filter volume).

Comparative Example 33
A cylindrical filter was produced in the same manner as in Comparative Example 32 except that silica gel (trade name: Silica gel B, specific surface area 450 m ² / g by BET method, manufactured by Toyoda Chemical Co., Ltd.) was used as the adsorbent. The amount of adsorbent supported on the obtained cylindrical filter was 80 g / liter (cylindrical filter volume).

Comparative Example 34
A cylindrical filter was produced in the same manner as in Example 86, except that silica gel (trade name: silica gel B, specific surface area 450 m ² / g by BET method, manufactured by Toyoda Chemical Co., Ltd., adsorbent) was used as the adsorbent. did. The amount of adsorbent supported on the obtained cylindrical filter was 100 g / liter (cylindrical filter volume).

Comparative Example 35
<Preparation of adsorbent coating solution>
500 parts by mass of silica gel (trade name: silica gel B, specific surface area 450 m ² / g by BET method, manufactured by Toyoda Chemical Co., Ltd., adsorbent), 480 parts by mass of methanol, 20 parts by mass of polyoxyethylene (10) octylphenyl ether Were mixed with a horizontal wet disperser DYNOMILL (manufactured by Shinmaru Enterprises) filled with 2 mmφ zirconia beads to prepare an adsorbent dispersion.

Next, 100 parts by mass of polyvinyl butyral (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name: 3000-K, binder) and 900 parts of methanol were mixed to obtain a binder solution. To 1000 parts of the adsorbent dispersion liquid, 247 parts by mass of the binder solution was added and mixed to obtain an adsorbent coating liquid. The mass ratio of the adsorbent / binder was 91/9, and the total concentration of the adsorbent and the binder relative to the total amount of the adsorbent coating liquid was 37% by mass.

<Preparation of adsorption sheet>
A 25 μm aluminum foil was subjected to a single-stage corrugation process with a step height of 1.5 mm and a pitch of 2.4 mm, and this was rolled up into a cylindrical shape to produce a cylindrical aluminum honeycomb body having a diameter of 10 cm and a length of 10 cm. The aluminum honeycomb body was immersed in the undercoat layer coating liquid A, pulled up, and air was applied from above to blow off excess alcohol in the cylindrical shape. Then, it heated at 80 degreeC for 30 minutes, and produced the undercoat layer. Next, it was pulled up after being immersed in the adsorbent coating solution and heated at 80 ° C. for 1 hour to form an adsorbing layer, thereby producing a cylindrical filter. The amount of the adsorbent supported on the obtained cylindrical filter was 70 g / liter (cylindrical filter volume).

Comparative Example 36
A cylindrical filter was produced in the same manner as in Comparative Example 32 except that zeolite (trade name: 13X, manufactured by Junsei Chemical Co., Ltd., pore size (catalog value) 1 nm), adsorbent) was used as the adsorbent. The amount of adsorbent supported on the obtained cylindrical filter was 80 g / liter (cylindrical filter volume).

Comparative Example 37
A cylindrical filter was produced in the same manner as in Example 86 except that zeolite (trade name: 13X, manufactured by Junsei Chemical Co., Ltd., pore size (catalog value) 1 nm), adsorbent) was used as the adsorbent. The amount of adsorbent supported on the obtained cylindrical filter was 100 g / liter (cylindrical filter volume).

Comparative Example 38
A cylindrical filter was produced in the same manner as in Comparative Example 35 except that zeolite (trade name: 13X, manufactured by Junsei Chemical Co., Ltd., pore diameter (catalog value) 1 nm), adsorbent) was used as the adsorbent. The amount of the adsorbent supported on the obtained cylindrical filter was 70 g / liter (cylindrical filter volume).

Comparative Example 39
100 parts by mass of a 10% by mass amorphous adsorbent aqueous dispersion was prepared, and 1 part by mass of 28% by mass ammonia water was mixed. Next, an anionic emulsion (main components: acrylic resin and colloidal silica, trade name: Movinyl (registered trademark) 8020, manufactured by Nichigo Movinyl Co., Ltd., concentration: 43% by mass, medium: water, binder) is adsorbent / binder. When the mixture was mixed so that the mass ratio of the agent was 91/9, the liquid immediately gelled, and the adsorbent coating liquid could not be prepared.

Comparative Example 40
100 parts by mass of a 10% by mass amorphous adsorbent aqueous dispersion was prepared, and 1 part by mass of 28% by mass ammonia water was mixed. Subsequently, a nonionic emulsion (main component: polyurethane, trade name: Bondic 1910NE, manufactured by Dainippon Ink and Co., Ltd., concentration 40% by mass, medium: water, binder) is adsorbent / binder mass ratio of 91 / When the mixture was mixed so as to be 9, the solution immediately gelled, and the adsorbent coating solution could not be prepared.

Comparative Example 41
100 parts by mass of a 10% by mass amorphous adsorbent aqueous dispersion was prepared, and 1 part by mass of acetic acid was mixed. Subsequently, a cationic emulsion (main component: polyurethane, trade name: Hydran 207, manufactured by Dainippon Ink Co., Ltd., concentration 40% by mass, medium: water, binder) is adsorbent / binder mass ratio of 91/9. When the mixture was mixed, the liquid immediately gelled and the coating liquid could not be prepared.

Comparative Example 42
<Preparation of adsorbent coating solution>
10 parts by mass of silica gel (trade name: Silica gel B, specific surface area 450 m ² / g by BET method, manufactured by Toyoda Chemical Co., Ltd., adsorbent) of water dispersion 100 parts by mass was prepared, and 1 part by mass of 28% by mass ammonia water was mixed. did. Subsequently, an anionic emulsion (main component: acrylic resin and colloidal silica, trade name: Movinyl 8020, manufactured by Nichigo Movinyl Co., Ltd., concentration: 43% by mass, medium: water, binder) is an adsorbent / binder mass ratio. Was mixed to make 91/9 to prepare an adsorbent coating solution. The total concentration of the adsorbent and the binder relative to the total amount of the adsorbent coating liquid was 11% by mass.

<Preparation of adsorption sheet>
A 25 μm aluminum foil was subjected to a single-stage corrugation process with a step height of 1.5 mm and a pitch of 2.4 mm, and this was rolled up into a cylindrical shape to produce a cylindrical aluminum honeycomb body having a diameter of 10 cm and a length of 10 cm. The aluminum honeycomb body was immersed in the undercoat layer coating liquid A, pulled up, and air was applied from above to blow off excess alcohol in the cylindrical shape. Then, it heated at 80 degreeC for 30 minutes, and produced the undercoat layer. Next, it was pulled up after being immersed in the adsorbent coating solution and heated at 80 ° C. for 1 hour to form an adsorbing layer, thereby producing a cylindrical filter. The amount of adsorbent supported on the obtained cylindrical filter was 60 g / liter (cylindrical filter volume).

Comparative Example 43
A cylindrical filter was produced in the same manner as in Comparative Example 41 except that zeolite (trade name: 13X, manufactured by Junsei Chemical Co., Ltd., pore size (catalog value) 1 nm), adsorbent) was used as the adsorbent. The amount of adsorbent supported on the obtained cylindrical filter was 60 g / liter (cylindrical filter volume).

Comparative Example 44
An amorphous adsorbent-containing paper (60 g / m ² ) was prepared by the wet paper making method with the following formulation.
Amorphous adsorbent 50 parts by weight Pulp (NBKP, CSF 480 ml) 45 parts by weight Fine cellulose (Daicel Selish 100S) 5 parts by weight

The obtained amorphous adsorbent-containing paper was corrugated at a step height of 1.9 mm and a pitch of 3.2 mm to produce a cylindrical filter having a diameter of 10 cm and a length of 10 cm. The amount of adsorbent supported on the obtained cylindrical filter was 80 g / liter (cylindrical filter volume).

Comparative Example 45
A 30 g / m ² glass fiber nonwoven fabric (manufactured by Oji Specialty Paper Co., Ltd.) was corrugated at a step height of 1.9 mm and a pitch of 3.2 mm to produce a cylindrical nonwoven fabric honeycomb body having a diameter of 10 cm and a length of 10 cm. This non-woven honeycomb body is immersed in a mixed liquid of 30 parts by mass of water glass 30 parts by mass and 70 parts by mass of an amorphous adsorbent, and then air-bleeded so as not to be clogged. Was blown into the nonwoven fabric for 2 hours, pre-dried, and further fired at 550 ° C. for 3 hours to produce a cylindrical filter. The amount of adsorbent supported on the obtained cylindrical filter was 100 g / liter (cylindrical filter volume).

[Storage stability of adsorbent coating solution]
After preparing the adsorbent coating solution, the state change when left at 25 ° C. for 24 hours was visually observed, and the results are shown in Table 8.

[Food fall]
The cylindrical filter was dried at 90 ° C. for 3 hours, and immediately left for 15 hours at 25 ° C. and a relative humidity of 30%. After that, it was left for 15 hours at 25 ° C. and a relative humidity of 80%, and when the relative humidity was lowered to 30%, the presence or absence of the adsorbent from the cylindrical filter was visually confirmed, and the results were shown. This is shown in FIG.

[Hygroscopic properties]
At a surface speed of 2 m / sec, air at 50 ° C. and absolute humidity 12 g / kg (DA) was blown for 30 minutes to dry the cylindrical filter, and then air at 20 ° C. and absolute humidity 12 g / kg (DA) was supplied. Air was blown to track the mass change of the cylindrical filter. By adsorbing moisture, the mass of the cylindrical filter is increased. Table 8 shows the “water adsorption amount per gram of adsorbent”, which is a value obtained by dividing the water adsorption amount W1 by the adsorbent amount W2 in the cylindrical filter. The mass measurement was performed after 1 minute, 2 minutes and 10 minutes from the start of blowing air at 20 ° C. and absolute humidity of 12 g / kg (DA), and the value after 10 minutes was taken as the saturation point.

In Examples 75 to 82 and Comparative Examples 32, 33, and 36, an adsorption layer containing an adsorbent and N-alkoxyalkylated polyamide (N-methoxymethylated nylon) is provided on the aluminum honeycomb body. Examples 75 to 82 using an amorphous adsorbent as the adsorbent had higher moisture adsorption amounts than Comparative Example 32 using silica gel A, Comparative Example 33 using silica gel B, and Comparative Example 36 using zeolite. showed that.

Examples 85 to 93 and Comparative Examples 34 and 37 are sheet base materials in which an adsorbent layer containing an adsorbent and a polyvinylidene fluoride polymer (polyvinylidene fluoride) is bonded to a glass fiber sheet and a polyethylene sheet. Provided. Examples 85 to 93 using an amorphous adsorbent as the adsorbent showed higher moisture adsorption amounts than Comparative Example 34 using silica gel B and Comparative Example 37 using zeolite.

Example 94 and Comparative Examples 35 and 38 are provided with an adsorption layer containing an adsorbent and polyvinyl butyral on an aluminum honeycomb body. Example 94 using an amorphous adsorbent as the adsorbent showed a higher moisture adsorption amount than Comparative Example 35 using silica gel B and Comparative Example 38 using zeolite.

Comparing Examples 75 to 93 and Examples 94 to 96, N-alkoxyalkylated polyamide (N-methoxymethylated nylon) or polyvinylidene fluoride polymer (polyvinylidene fluoride) was used as a binder. Examples 75 to 93 showed higher moisture adsorption. In Examples 94 to 96, in which the binder is polyvinyl butyral or acrylic resin, it is considered that the moisture adsorbent was lowered because the surface of the amorphous adsorbent was covered with the binder.

The amorphous adsorbent-containing paper of Comparative Example 44, to which an amorphous adsorbent was added during wet papermaking, had a low moisture adsorption amount. This was because the amorphous adsorbent was coated with hydroxyl-containing pulp or cellulose. It is thought that it was because it was done. On the other hand, Examples 75 to 93 using a binder that does not have a functional group that is easily adsorbed to the amorphous adsorbent showed a high moisture adsorption amount.

In Comparative Example 45 subjected to the firing treatment, the moisture adsorption amount was low. This is presumably because the amorphous adsorbent was modified by the firing treatment. In Examples 75 to 96, since the firing step is unnecessary, there is no modification of the amorphous adsorbent. Moreover, it can apply to various sheet | seat base materials, such as a nonwoven fabric, a film, and metal foil.

In Comparative Examples 39 to 43, when water is used as the medium, in Comparative Examples 42 and 43 in which the adsorbent is silica gel B or zeolite, the amount of adsorbent supported due to the precipitate generated in the coating liquid. However, it was able to be applied. On the other hand, in Comparative Examples 39 to 41 in which the adsorbent was an amorphous adsorbent, the coating solution gelled and could not be applied to the sheet substrate. In the case of an amorphous adsorbent, when an organic solvent was used as a medium as in Examples 75 to 96, coating onto a sheet substrate became possible.

In Examples 76, 77, 86 to 88, and Examples 94 to 96, the mass ratio of the adsorbent / binder is about 90/10 (92/8 to 88/12). In Examples 94 to 96 in which the binder was polyvinyl butyral and acrylic resin, the adsorbent coating solution gradually gelled, but the binder was N-alkoxyalkylated polyamide (N-methoxymethylated nylon). In Examples 76, 77, and 86 to 88, which are polyvinylidene fluoride polymers (polyvinylidene fluoride), no change was observed in the adsorbent coating solution.

In Examples 75 to 82, powder falling was confirmed in Example 75 where the mass ratio of the adsorbent / binder was 94/6. In Examples 79 to 82 in which the mass ratio of the adsorbent / binder was 80/20 or less, the adsorbent coating solution gradually gelled, and the amount of adsorbent supported decreased. In Examples 76 to 78 in which the mass ratio of the adsorbent / binder was 92/8 to 85/15, the preservability of the adsorbent coating solution was good, and no powder falling off was observed.

In Examples 84 to 93, powder falling was confirmed in Example 85 in which the mass ratio of the adsorbent / binder was 94/6. In Examples 89 to 93 in which the mass ratio of the adsorbent / binder was 86/14 or less, gelation of the adsorbent coating solution and generation of precipitates were observed, and the amount of adsorbent supported was reduced. In Examples 86 to 88 in which the mass ratio of the adsorbent / binder was 92/8 to 88/12, the preservability of the adsorbent coating solution was good, and no powder falling off was observed.

The moisture adsorbent, sheet material for dehumidification of the present invention, filter material for dehumidification are desiccant air conditioners, art materials, electrical products, crafts, packaging materials for storing and transporting clothes, housing interior materials, It can be used for indentation and chestnut moisture absorbents, heat exchange elements, and the like.

The moisture absorbing / releasing sheet and moisture absorbing / releasing structure of the present invention can be used as a dehumidifying device with very high moisture absorbing / releasing efficiency used in a desiccant air conditioning system or the like. Further, it can be used as a non-combustible building material or a non-combustible panel having a hygroscopic function by being bonded to a panel material such as various non-combustible building materials.

The coating liquid of the present invention can adhere an adsorbent to the surface of the sheet substrate, and the adsorbing sheet of the present invention includes a packaging material, a dehumidifying sheet, an interior material, a filter, a humidity control element, and a heat exchange element. For example, building air conditioning vaporization type humidification element, fuel cell humidification element, dehumidifier dehumidifier, water absorption transpiration element such as vending machine, water absorption transpiration element for cooling, desiccant air conditioner dehumidification rotor It can be used for elements, organic gas (VOC), carbon monoxide, carbon dioxide, nitrogen oxide (NO _x ) and other gas removal systems, heat exchange or heat transfer systems, and humidity control (dehumidification or humidification) systems.

1 Stainless steel pipe filled with filter material for dehumidification 2 Stainless steel pipe (upstream side)
3 Stainless steel pipe (downstream)
4 Thermo-hygrometer (upstream side)
5 Thermo-hygrometer (downstream side)
6 On-off valve (upstream side)
7 On-off valve (downstream)

Claims (24)

Moisture adsorbent comprising an amorphous aluminum silicate having a Si / Al ratio of 0.7 to 1 and having peaks in the vicinity of -78 ppm and -87 ppm in a ²⁹ Si solid state NMR spectrum and a hygroscopic salt . The moisture according to claim 1, wherein the hygroscopic salt is at least one selected from the group consisting of a metal halide salt, a metal sulfate salt, a metal acetate salt, an amine salt, a phosphate compound, a guanidine salt, and a metal hydroxide. Adsorbent. The moisture adsorbent according to claim 1, wherein the hygroscopic salt is a metal halide salt or a guanidine salt. A sheet material for dehumidification comprising the moisture adsorbent according to any one of claims 1 to 3. A filter material for dehumidification comprising the moisture adsorbent according to any one of claims 1 to 3. An amorphous aluminum silicate having a Si / Al ratio of 0.7 to 1.0 and having peaks near -78 ppm and -87 ppm in a ²⁹ Si solid state NMR spectrum and a water-soluble silicate. A moisture-absorbing / releasing sheet. The water-soluble silicate is at least one selected from the group consisting of sodium silicate, disodium silicate, disodium silicate pentahydrate, sodium silicate nonahydrate and potassium silicate. Item 7. The hygroscopic sheet according to item 6. The moisture-absorbing / releasing sheet according to claim 6 or 7, wherein the water-soluble silicate is contained in an amount of 1 to 50% by mass based on the total amount of the amorphous aluminum silicate and the water-soluble silicate. The hygroscopic sheet according to any one of claims 6 to 8, further comprising a hygroscopic salt. Amorphous aluminum silicate and water-soluble silicate having a Si / Al ratio of 0.7 to 1.0 and peaks near −78 ppm and −87 ppm in a ²⁹ Si solid state NMR spectrum are supported on a sheet. And a method for producing a moisture-absorbing / releasing sheet, comprising a step of baking the sheet at a temperature of 920 ° C. or lower. A composition comprising an amorphous aluminum silicate having a Si / Al ratio of 0.7 to 1.0 and peaks in the vicinity of -78 ppm and -87 ppm in a ²⁹ Si solid state NMR spectrum and a water-soluble silicate A moisture-absorbing / releasing structure characterized by being supported on a honeycomb-like structure. The water-soluble silicate is at least one selected from the group consisting of sodium silicate, disodium silicate, disodium silicate pentahydrate, sodium silicate nonahydrate and potassium silicate. Item 12. The moisture absorbing / releasing structure according to Item 11. The moisture-absorbing / releasing structure according to claim 11 or 12, wherein the water-soluble silicate is contained in an amount of 1 to 50 mass% with respect to the total of the amorphous aluminum silicate and the water-soluble silicate. The hygroscopic structure according to any one of claims 11 to 13, further comprising a hygroscopic salt. A composition comprising an amorphous aluminum silicate having a Si / Al ratio of 0.7 to 1.0 and peaks in the vicinity of -78 ppm and -87 ppm in a ²⁹ Si solid state NMR spectrum and a water-soluble silicate A method for producing a moisture absorbing / releasing structure, comprising: supporting the honeycomb structure on a honeycomb structure; and firing the honeycomb structure at a temperature of 920 ° C. or lower. ^{29. An} adsorption sheet comprising an adsorption layer containing at least an adsorbent and a binder on a sheet substrate, wherein the adsorbent has an Si / Al ratio of 0.7 to 1.0, and ²⁹ A sheet for adsorption, which is an amorphous aluminum silicate having peaks at around -78 ppm and around -87 ppm in a Si solid state NMR spectrum. The adsorption sheet according to claim 16, wherein the binder is an organic solvent-soluble polymer. The adsorption sheet according to claim 17, wherein the organic solvent-soluble polymer is a vinylidene fluoride-based polymer. The adsorption sheet according to claim 17, wherein the organic solvent-soluble polymer is N-alkoxyalkylated polyamide. The adsorption sheet according to any one of claims 16 to 19, wherein a mass ratio of the adsorbent and the binder in the adsorption layer is 93/7 to 70/30. A coating liquid containing at least an adsorbent, a binder, and a medium, wherein the adsorbent has a Si / Al ratio of 0.7 to 1.0 and a value near -78 ppm in a ²⁹ Si solid state NMR spectrum. And an amorphous aluminum silicate having a peak at around -87 ppm, the medium is an organic solvent, and the binder is an organic solvent-soluble polymer. The coating liquid according to claim 21, wherein the organic solvent-soluble polymer is a vinylidene fluoride-based polymer. The coating liquid according to claim 21, wherein the organic solvent-soluble polymer is N-alkoxyalkylated polyamide. An adsorbing sheet having an adsorbing layer formed by applying the coating liquid according to any one of claims 21 to 23 onto a sheet substrate.

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