JP2009108167A - Thermal storage microcapsule - Google Patents

Abstract

The present invention provides a heat storage microcapsule including a water-soluble heat storage material, realizing higher sealing performance and suppressing leakage of the inclusion, and a method for manufacturing the same.
The heat storage microcapsule includes a core material made of one or more water-soluble heat storage materials selected from the group consisting of saccharides, sugar alcohols, inorganic salts, and inorganic salt hydrates; and the core material And a second capsule wall made of a polymer material covering the first capsule wall.
[Selection] Figure 1

Description

  The present invention relates to a heat storage microcapsule that contains a water-soluble heat storage material, and more particularly to a heat storage microcapsule that can suppress leakage of the water-soluble heat storage material contained therein.

  As a heat exchange means between the heat storage material and the heat medium, direct contact is the most efficient method. However, since the heat storage material and the heat medium often interact physically and chemically, indirect contact is unavoidable.

  As a heat exchange means by this indirect contact, a method of encapsulating a heat storage material and exchanging heat with a heat medium via a capsule membrane can be mentioned. This method is very effective because the surface area per unit volume of the heat storage material is increased, and various attempts have been made to reduce the size of capsules in order to make heat transfer more effective. For example, an encapsulation method using a composite emulsion method (see Patent Document 1), a method of spraying a thermoplastic resin on the surface of the heat storage material particles (see Patent Document 2), and forming a thermoplastic resin in a liquid on the surface of the heat storage material particles The manufacturing method of the thermal storage microcapsule, such as the method to perform (refer patent document 3), is disclosed.

  In the microcapsules encapsulating the heat storage material disclosed in these patent documents (hereinafter referred to as heat storage microcapsules), polystyrene or polyacrylonitrile obtained by a method such as an interfacial polymerization method or an in-situ method is used as the capsule wall material. In addition to polyamide, polyacrylamide, ethyl cellulose, polyurethane, organic polymers such as aminoplast resin such as urea formalin resin and melamine resin are used. In addition, as the heat storage material, a latent heat storage material that stores or dissipates heat by phase change is used. Specifically, there are many water-insoluble heat storage materials such as n-paraffin, iso-paraffin, fatty acid, higher alcohol, and polymer. It is used.

  Incidentally, the amount of heat that can be stored by the heat storage material (heat storage amount) is substantially determined by the amount of latent heat of fusion (ΔH) of the heat storage material, and the heat storage amount of the water-insoluble heat storage material is as small as 120 to 240 kJ / kg (see FIG. 15). Therefore, in order to increase the amount of heat stored per unit amount, a substance having a large amount of latent heat of fusion (ΔH = 160 to 350 kJ / kg), specifically, sugars, sugar alcohols, inorganic salts, inorganic salt hydrates, etc. Thermal storage microcapsules containing water-soluble thermal storage materials have been studied. For example, a method for manufacturing a heat storage material-encapsulated microcapsule (see Patent Document 4), a method for manufacturing a microencapsulated heat storage material (see Patent Document 5), a microcapsule for a heat storage material (see Patent Document 6), and the like are disclosed. And such a thermal storage microcapsule is used as a heat retention agent of a fiber material or a sheet material, or it mixes in a fluid and is utilized as a heat transport medium.

  However, since the heat storage microcapsule is in a powder form, it is difficult to use it as it is. Moreover, since it is difficult to obtain a sufficient heat storage effect, it is not suitable for use as a heat transport medium. Therefore, a method in which the heat storage microcapsules are dispersed in an aqueous solvent and used as a slurry has been studied (for example, see Patent Documents 7 and 8).

On the other hand, production of a heat storage microcapsule having a double wall and a heat storage microcapsule having a composite wall has also been studied. For example, a method for producing a water-containing microcapsule that forms a double wall using the permeability to a microcapsule (see Patent Document 9), and a method for producing a composite wall microcapsule having an inner wall film and an outer wall film (Patent Document 10). Reference), a method for producing a microcapsule for heat storage in which a capsule wall made of calcium silicate is formed around the core material (see Patent Document 11), a double membrane made of polymethyl methacrylate and aromatic polyamide around the core material A method for manufacturing a heat storage microcapsule having a structure (see Patent Document 12), a method for manufacturing a heat storage microcapsule powder in which polyvinyl alcohol is present at the interface of the capsule membrane (see Patent Document 13), and the like are disclosed. Yes.
Japanese Patent Laid-Open No. 62-1452 JP-A 62-45680 Japanese Patent Laid-Open No. 62-149334 JP-A-62-2225241 JP-A-61-192785 Japanese Patent Laid-Open No. 08-259932 JP 2007-119715 A JP 2006-63314 A Japanese Patent Laid-Open No. 02-258052 Japanese Patent Laid-Open No. 06-238158 Japanese Patent Laid-Open No. 07-26251 Japanese Patent Application Laid-Open No. 07-213890 JP 2006-274086 A

  From the viewpoint of improving the usability of the heat storage microcapsules, when the conventional heat storage microcapsules described above are dispersed in an aqueous solvent to form a slurry, the wall material of the heat storage microcapsules is required to have high sealing performance. In particular, when heat storage microcapsules containing a water-soluble heat storage material are dispersed in an aqueous solvent to form a slurry, higher sealing performance is required as compared to heat storage microcapsules containing paraffin or the like. However, the above-described conventional heat storage microcapsules cannot satisfy the requirements, and the inclusions easily leak (see FIG. 16). For example, when a heat storage microcapsule containing a water-insoluble heat storage material is dispersed in an aqueous solvent to form a slurry, the residual rate of the heat storage material is almost 100% (see FIG. 16A). When the heat storage microcapsules containing the water-soluble heat storage material were dispersed in an aqueous solvent to form a slurry, the residual rate of the heat storage material was almost 0% (see FIG. 16B).

  Therefore, the present invention has been made in view of the above problems, and the purpose thereof is to realize higher sealing performance and suppress leakage of inclusions in a heat storage microcapsule including a water-soluble heat storage material. An object of the present invention is to provide a heat storage microcapsule that can be used and a method for manufacturing the same.

  The inventors of the present invention have made extensive studies to solve the above problems. As a result, a water-soluble heat storage material that stores or dissipates heat by phase change is used as a core material, and the first capsule wall that covers the core material and the second capsule wall that is made of a polymer material that covers the first capsule wall are included. According to the heat storage microcapsule, it has been found that a high sealing performance can be realized as compared with the conventional one, and the leakage of the water-soluble heat storage material can be suppressed even when the slurry is dispersed in an aqueous solvent to complete the present invention. It came to do. More specifically, the present invention provides the following.

  (1) A core substance made of one or more water-soluble heat storage materials selected from the group consisting of saccharides, sugar alcohols, inorganic salts, and inorganic salt hydrates, and a first capsule wall covering the core substance And a second capsule wall made of a polymer material covering the first capsule wall.

  Since the heat storage microcapsule (1) has a core substance composed of a water-soluble heat storage material that stores or dissipates heat by phase change, it has a large amount of heat storage per unit amount. For this reason, the heat storage microcapsule (1) exhibits excellent heat storage performance even in a small amount. Moreover, the capsule wall which coat | covers a core substance consists of a 1st capsule wall and the 2nd capsule wall which consists of a polymer material which coat | covers the 1st capsule wall. That is, the capsule wall has a double wall structure, and even if a minute hole or a defect is generated on the surface of the first capsule wall, these holes and Can close the defect. For this reason, compared with the conventional heat storage microcapsule, the leakage of the heat storage material to be included can be effectively suppressed. Moreover, since the first capsule wall can be reinforced by the second capsule wall, the fastness of the heat storage microcapsule can be improved.

  (2) The heat storage microcapsule according to (1), wherein the first capsule wall is made of a composite material of an inorganic compound and an organic polymer compound.

  In the heat storage microcapsule (2), the first capsule wall is formed of a composite material of an inorganic compound and an organic polymer compound. By forming the first capsule wall with a composite material of an inorganic compound and an organic polymer compound, the adhesion between the first capsule wall and the second capsule wall is improved, and is physically and chemically stable and excellent in heat resistance. Thermal storage microcapsules are obtained.

  (3) The inorganic compound is one or two or more selected from the group consisting of calcium silicate, magnesium silicate, zinc silicate, tin silicate, and iron silicate. Heat storage microcapsules.

  In the heat storage microcapsule (3), silicate is used to form the first capsule wall composed of the composite wall. For this reason, since a 1st capsule wall can be formed using interfacial polymerization, the productivity of a thermal storage microcapsule can be improved more. Moreover, the heat resistance and fastness of the heat storage microcapsule can be improved.

  (4) The heat storage microcapsule according to (2) or (3), wherein the organic polymer compound is a polyamide resin.

  In the heat storage microcapsule (4), a polyamide resin is used to form the first capsule wall made of a composite wall. For this reason, the heat resistance and fastness of the heat storage microcapsule can be further improved. In addition, the adhesion between the first capsule wall and the second capsule wall made of a polymer material can be improved.

  (5) The second capsule wall is made of one or two or more polymer materials selected from the group consisting of polyurea, polyamide, polyimide, polyurethane, polystyrene, and acrylic resin. (1) to (4 ) Thermal storage microcapsule according to any one of the above.

  In the heat storage microcapsule of (4), one or two or more polymer materials selected from the group consisting of polyurea, polyamide, polyimide, polyurethane, polystyrene, and acrylic resin are used for forming the second capsule wall. According to the heat storage microcapsule having the second capsule wall formed of these polymer materials, higher heat resistance and fastness can be realized. Further, with these polymer materials, the second capsule wall can be formed by interfacial polymerization on the surface of the first capsule wall, and the productivity of the heat storage microcapsules can be further increased.

  (6) A slurry obtained by dispersing the heat storage microcapsule according to any one of (1) to (5) in an aqueous solvent.

  According to the heat storage microcapsules of (1) to (5), since leakage of the water-soluble heat storage material that is a core substance can be suppressed, it can be dispersed in an aqueous solvent such as water or alcohol and used as a slurry. For this reason, it can be preferably used as a heat transport fluid for heating and cooling various electric devices and transport machines.

  (7) The composition further comprises one or more dispersants selected from the group consisting of polycarboxylic acid, vinyl acetate, maleic acid copolymer, polyvinyl alcohol, and fatty acid esters (6) Slurry.

  A kind selected from the group consisting of polycarboxylic acid, vinyl acetate, maleic acid copolymer, polyvinyl alcohol, and fatty acid esters in a slurry obtained by dispersing the heat storage microcapsules of (1) to (5) in an aqueous solvent Alternatively, the dispersion stability can be improved by adding two or more kinds of dispersants. As a result, aggregation of the heat storage microcapsules in the slurry can be suppressed, and stable heat storage performance can be obtained.

  (8) A method for producing a heat storage microcapsule comprising: a core substance made of a water-soluble heat storage material; a first capsule wall covering the core substance; and a second capsule wall covering the first capsule wall. The step of forming an aqueous phase by adding and mixing the water-soluble heat storage material in an aqueous solution containing silicate ions and polyamine, and an oil mainly composed of the aqueous phase and a hydrocarbon solvent. A step of preparing a W / O dispersion by mixing the phases and heating and stirring; and from the group consisting of the W / O dispersion, Ca ions, Mg ions, Zn ions, Sn ions, and Fe ions While mixing with an inorganic ion solution containing one or two or more kinds of inorganic ions selected and heating and stirring, the hydrocarbon-based solution containing a dicarboxylic acid halide is added dropwise to the water-soluble solution. A step of obtaining a heat storage microcapsule precursor having a first capsule wall encapsulating a heat material and a composite of polyamide resin and silicate, the heat storage microcapsule precursor, and a monomer Forming a second capsule wall made of a polymer material on the surface of the first capsule wall by mixing and stirring the monomer solution, and a method for producing a thermal storage microcapsule.

  According to the method for producing a heat storage microcapsule of (8), a heat storage microcapsule adopting a double wall structure can be manufactured as a capsule wall covering a core material composed of a water-soluble heat storage material. More specifically, a heat storage microcapsule having a first capsule wall made of a composite wall covering a core substance made of a water-soluble heat storage material and a second capsule wall made of a polymer material covering the first capsule wall is manufactured. can do. Therefore, it is possible to provide a heat storage microcapsule that has a large amount of heat storage per unit amount, has high sealing properties, and can suppress leakage of the water-soluble heat storage material contained therein.

  According to the present invention, it is possible to provide a heat storage microcapsule that has a large heat storage amount per unit amount, has high sealing properties, and can suppress leakage of the water-soluble heat storage material contained therein, and a method for manufacturing the same. In addition, by dispersing and stabilizing such heat storage microcapsules in an aqueous solvent, it is possible to provide a slurry that is easy to handle in use.

  Embodiments of the present invention will be specifically described below with reference to the drawings.

<Water-soluble heat storage material>
The water-soluble heat storage material constituting the core material of the heat storage microcapsule according to this embodiment performs heat storage or heat dissipation using latent heat accompanying phase change. Specifically, one kind or two or more kinds selected from the group consisting of sugar, sugar alcohol, inorganic salt, and inorganic salt hydrate are used.

  Moreover, carbon, metal powder, alcohol, etc. may be added for the purpose of adjusting the thermal conductivity and specific gravity of the heat storage microcapsules and for the purpose of preventing overcooling.

<First capsule wall>
In the heat storage microcapsule according to this embodiment, the first capsule wall covering the core substance is preferably formed from a composite material of an inorganic compound and an organic polymer compound. By forming the first capsule wall with a composite material of an inorganic compound and an organic polymer compound, the adhesion between the first capsule wall and the second capsule wall is improved, and is physically and chemically stable and excellent in heat resistance. Thermal storage microcapsules are obtained.

  As the inorganic compound, one or two or more silicates selected from the group consisting of calcium silicate, magnesium silicate, zinc silicate, tin silicate and iron silicate are used. These may be used individually by 1 type and may use multiple types together. Since the first capsule wall can be formed using interfacial polymerization, the productivity of the heat storage microcapsules can be further increased. Moreover, the heat resistance and fastness of the heat storage microcapsule can be improved.

  As the organic polymer compound, a polyamide resin is preferably used. By using the polyamide resin for forming the first capsule wall, the heat resistance and fastness of the heat storage microcapsule can be further improved. In addition, the adhesion between the first capsule wall and the second capsule wall made of a polymer material can be improved.

<Second capsule wall>
In the heat storage microcapsule according to the present embodiment, the second capsule wall covering the first capsule wall is made of a polymer material. As described above, by adopting a double wall structure for the capsule wall, even if minute holes or defects are generated on the surface of the first capsule wall, these holes are formed by the second capsule wall made of the polymer material. And can block defects. For this reason, compared with the conventional heat storage microcapsule, the leakage of the water-soluble heat storage material to be included can be effectively suppressed. Moreover, since the first capsule wall can be reinforced by the second capsule wall, the fastness of the heat storage microcapsule can be improved.

  As a preferred polymer material for forming the second capsule wall, one or more selected from the group consisting of polyurea, polyamide, polyimide, polyurethane, polystyrene, and acrylic resin are preferably used. These may be used individually by 1 type and may use multiple types together.

<Method for producing thermal storage microcapsules>
An example of the manufacturing method of the thermal storage microcapsule which concerns on this embodiment is demonstrated along the flow shown in FIG. In this manufacturing method, silicate is used as the inorganic compound constituting the composite material with the first capsule wall, and an aqueous solution and an inorganic ion solution containing silicate ions are used as the raw material. Sodium acid aqueous solution and calcium chloride aqueous solution are used. Similarly, a polyamide resin is used as the organic polymer compound constituting the composite material, polyamine and dicarboxylic acid halide are used as raw materials, and diethylenetriamine (DETA) and phthaloyl dichloride (PDC) are used as examples of the raw materials. Moreover, polyurea is used as the polymer material constituting the second capsule wall, and toluene-2,4-diisocyanate is used as the raw material. Here, “polyamine” refers to a generic name of an aliphatic compound having two or more amino groups (—NH ₂ ) or imino groups (═NH).

[Step (1)]
First, an aqueous phase containing a water-soluble heat storage material typified by erythritol and an aqueous solution containing diethylenetriamine (DETA) is added to and mixed with an aqueous sodium silicate solution.

[Step (2)]
After mixing an oil phase mainly composed of a hydrocarbon solvent such as kerosene with the water phase prepared in step (1), the mixture is heated and stirred with a stirrer such as a homogenizer to produce fine particles, and a W / O dispersion system is prepared. Make it. At this time, the dispersion stability of the W / O dispersion can be improved by adding a dispersant such as sorbitan monooleate as represented by “Span 80” manufactured by Wako Pure Chemical Industries, Ltd. to the oil phase. it can. Moreover, the heating temperature at the time of preparing the W / O dispersion is appropriately set depending on the type of water-soluble heat storage material used as the core substance.

[Step (3)]
Separately from the W / O dispersion in step (2), in a hydrocarbon solvent such as kerosene, an aqueous solution of calcium chloride and a phosphate ester-based surfactant represented by di (2-ethylhexyl) phosphate (D2EHPA) An agent or an acidic monophosphonic acid monoester surfactant is added and mixed, and stirred at room temperature with an impeller or the like to prepare an inorganic ion solution. Here, as the inorganic ion solution, not only the above-mentioned Ca ions, but also a solution containing one or more inorganic ions selected from the group consisting of Mg ions, Zn ions, Sn ions, and Fe ions. Used. These inorganic ions may be used individually by 1 type, and may use multiple types together.

  In addition to the W / O dispersion and the inorganic ion solution, by adding and mixing a dicarboxylic acid halide represented by phthaloyl dichloride (PDC) in a hydrocarbon solvent such as kerosene, A hydrocarbon-based solution containing a dicarboxylic acid halide is prepared. Also for this solution, by adding a dispersant such as sorbitan monooleate represented by “Span 80” manufactured by Wako Pure Chemical Industries, the dispersion stability of the dicarboxylic acid halide in the hydrocarbon solvent is improved. be able to.

  Subsequently, the inorganic ion solution is added and mixed while stirring the W / O dispersion obtained in step (2) at room temperature with an impeller or the like. Thereafter, while the mixed solution is heated and stirred, a hydrocarbon-based solution containing a dicarboxylic acid halide is gradually added dropwise to start and advance the synthesis reaction of calcium silicate and the synthesis reaction of the polyamide resin at the interface. The state of these synthesis reactions is schematically shown in FIGS. As shown in FIG. 2, Ca ions 11 contained in the oil phase react with silicate ions 12 contained in the aqueous phase, and calcium silicate 15 is synthesized (see FIG. 3). At the same time, phthaloyl dichloride 13 contained in the oil phase reacts with diethylenetriamine 14 contained in the aqueous phase to form a polyamide resin 16, and the calcium silicate 15 and the polyamide resin 16 are composited. A capsule wall 2 is formed (see FIG. 4).

[Step (4)]
The heat storage microcapsule precursor on which the first capsule wall 2 has been formed in the step (3) is washed by demulsification with ethanol or the like. Then, the washed heat storage microcapsule precursor is mixed with the monomer solution. Here, the monomer solution is prepared by mixing, for example, toluene-2,4-diisocyanate as a raw material for the polymer material in a hydrocarbon solvent such as kerosene.

  The monomer solution mixed with the heat storage microcapsule precursor is stirred at room temperature to initiate and advance the polyurea synthesis reaction on the surface of the heat storage microcapsule precursor. The state of this synthesis reaction is schematically shown in FIGS. As shown in FIG. 5, the toluene-2,4-diisocyanate 17 contained in the monomer solution reacts with the amide group contained on the surface of the polyamide resin 16 to synthesize polyurea, thereby forming the second capsule wall 3. (See FIG. 6).

  Finally, the first capsule wall is composed of a composite wall composed of a polyamide resin and calcium silicate, which covers a core material composed of erythritol fine particles by demulsifying and washing using an amphoteric solvent such as ethanol. 2 and a second capsule wall 3 made of polyurea covering the first capsule wall 2 can be produced.

<Slurry using thermal storage microcapsules>
The heat storage microcapsules obtained by this production method can be dispersed in an aqueous solvent and used as a slurry. By using it as a slurry, the heat storage microcapsules can be handled more easily, and the heat storage effect of the heat storage microcapsules can be obtained sufficiently. As a heat transport fluid that heats and cools various electrical devices and transport machines, etc. Can be preferably used.

  When forming a slurry by dispersing in an aqueous solvent, one or more dispersants selected from the group consisting of polycarboxylic acid, vinyl acetate, maleic acid copolymer, polyvinyl alcohol, and fatty acid esters are further added. It is preferable to contain. By containing the dispersant, the dispersion stability of the heat storage microcapsules in the aqueous solvent can be improved. As a result, aggregation of the heat storage microcapsules in the slurry can be suppressed, and stable heat storage performance can be obtained.

  Next, the present invention will be described in more detail based on examples, but the present invention is not limited thereto.

<Example 1>
Thermal storage microcapsules were manufactured according to the flow shown in FIG. First, 10 g of erythritol (manufactured by Tokyo Kasei Co., Ltd.) and 0.5 g of DETA (manufactured by Alfa Aesar) are mixed in 10 ml of an aqueous solution of Na ₂ SiO ₃ (sodium silicate: manufactured by Kanto Chemical Co., Inc.) ³ kmol / m ^3. Thus, an aqueous phase (W phase) was prepared.

  An oil phase (O phase) was prepared by adding and mixing 1.6 g of sorbitan monooleate (“Span 80” manufactured by Wako Pure Chemical Industries, Ltd.) as a dispersant to 120 ml of kerosene (manufactured by Wako Pure Chemical Industries, Ltd.).

  The prepared water phase and oil phase were mixed, and then stirred for 10 minutes at a stirring speed of 3000 rpm at a liquid temperature of 60 ° C. with a homogenizer to prepare a W / O dispersion.

To 450 ml of kerosene (manufactured by Wako Pure Chemical Industries, Ltd.), 50 g of D2EHPA (manufactured by Kanto Chemical Co., Ltd.) and 500 ml of a ₂ kmol / m ³ aqueous solution of CaCl ₂ (calcium chloride: manufactured by Kanto Chemical Co., Ltd.) were mixed. Next, after stirring for 24 hours at room temperature with a stirrer, the aqueous phase was removed using a separatory funnel to prepare an inorganic ion solution.

  Further, 30 ml of kerosene (manufactured by Wako Pure Chemical Industries, Ltd.) is mixed with 1.0 g of phthaloyl dichloride (1.0 g manufactured by Wako Pure Chemical Industries, Ltd.) and 0.5 g of a dispersant “Span80” (manufactured by Wako Pure Chemical Industries, Ltd.) A hydrocarbon-based solution containing a dicarboxylic acid halide was prepared.

  50 ml of an inorganic ion solution was mixed with the prepared W / O dispersion. Then, after stirring for 2 hours at 200 rpm at 60 ° C. with an impeller, a hydrocarbon-based solution containing a dicarboxylic acid halide was added at a rate of 0.5 ml / min while stirring at 150 rpm for 24 hours. Stirring was continued to perform an interfacial reaction to form a first capsule wall containing a water-soluble heat storage material. The heat storage microcapsule precursor in which the first capsule wall was formed was taken out from the W / O dispersion by filtration using a filter paper (manufactured by ADVANTEC; 5C 100CIRCLES).

  Heat storage microcapsule precursor prepared by mixing 0.9 ml of toluene-2,4-diisocyanate (manufactured by Wako Pure Chemical Industries) with 100 ml of kerosene (manufactured by Wako Pure Chemical Industries, Ltd.) and taking out the monomer solution from the W / O dispersion system. Was mixed into the monomer solution. This was stirred at room temperature at 150 rpm to form a second capsule wall made of polyurea on the surface of the heat storage microcapsule precursor. The heat storage microcapsule precursor formed with the second capsule wall was taken out of the monomer solution by filtration using a filter paper (manufactured by ADVANTEC; 5C 100CIRCLES), washed with ethanol and dried to obtain heat storage microcapsules.

<Comparative Example 1>
As a comparative example, a heat storage microcapsule was manufactured along the flow shown in FIG. First, 10 g of erythritol (manufactured by Tokyo Chemical Industry Co., Ltd.) was mixed with 10 ml of a ³ kmol / m ³ aqueous solution of Na ₂ SiO ₃ (sodium silicate: manufactured by Kanto Chemical Co., Inc.) to prepare an aqueous phase (W phase).

  An oil phase (O phase) was prepared by adding and mixing 1.6 g of sorbitan monooleate (“Span 80” manufactured by Wako Pure Chemical Industries, Ltd.) as a dispersant to 120 ml of kerosene (manufactured by Wako Pure Chemical Industries, Ltd.).

  The prepared water phase and oil phase were mixed, and then stirred for 10 minutes at a stirring speed of 3000 rpm at a liquid temperature of 60 ° C. with a homogenizer to prepare a W / O dispersion.

To 450 ml of kerosene (manufactured by Wako Pure Chemical Industries, Ltd.), 50 g of D2EHPA (manufactured by Kanto Chemical Co., Ltd.) and 500 ml of a ₂ kmol / m ³ aqueous solution of CaCl ₂ (calcium chloride: manufactured by Kanto Chemical Co., Ltd.) were mixed. Next, after stirring for 24 hours at room temperature with a stirrer, the aqueous phase was removed using a separatory funnel to prepare an inorganic ion solution.

  50 ml of an inorganic ion solution was mixed with the prepared W / O dispersion. And it stirred for 24 hours at 200 rpm at 60 degreeC with the impeller, interface reaction was performed, and the formation of the 1st capsule wall which encloses a water-soluble heat storage material was performed. After the formation of the first capsule wall, the heat storage microcapsules were taken out from the W / O dispersion by filtration using a filter paper (manufactured by ADVANTEC; 5C 100CIRCLES), washed with ethanol and dried to obtain heat storage microcapsules.

<Evaluation of sealing performance>
The heat storage microcapsules obtained in Example 1 and Comparative Example 1 were evaluated for sealing performance.

  For the heat storage microcapsules obtained in Example 1 and Comparative Example 1, the heat of fusion of the water-soluble heat storage material was measured using a differential scanning calorimeter (DSC: SSC / 5200 manufactured by Seiko Instruments). The amount of heat of fusion at this time was defined as the amount of heat stored before solution dispersion.

  On the other hand, 500 mg of the heat storage microcapsules obtained in Example 1 and Comparative Example 1 were dispersed in 50 ml of ion-exchanged water, and stirred with a stirrer at 300 rpm for 60 minutes to form a slurry. The heat storage microcapsule was taken out from the slurry after stirring by filtration using a filter paper (manufactured by ADVANTEC; 5C 100CIRCLES), and the heat storage microcapsule on the filter paper was dried for 30 minutes in a constant temperature bath at 100 ° C. The heat of fusion of the dried thermal storage microcapsules was measured using a suggested thermal scanning calorimeter (DSC: SSC / 5200 manufactured by Seiko Instruments). The amount of heat of fusion at this time was defined as the amount of heat stored after dispersion of the solution.

  And the heat storage material residual rate (%) = heat storage amount after solution dispersion [J / g] / heat storage amount before solution dispersion [J / g], the sealing performance of the heat storage microcapsules was evaluated. The results of evaluating the sealing performance at this time are shown in FIG.

  As a result, in the heat storage microcapsules obtained in Example 1, the heat storage amount (a) before solution dispersion was 172.27 [J / g], and the heat storage amount (b) after solution dispersion was 146.95 [J / g]. g], and the heat storage material residual ratio (b / a) increased to 85.3%. Therefore, the heat storage microcapsule obtained in Example 1 was able to suppress leakage of the water-soluble heat storage material contained in the heat storage microcapsule containing the water-soluble heat storage material and realize high sealing performance (FIG. 14 (A)).

  On the other hand, in the heat storage microcapsule obtained in Comparative Example 1, the heat storage amount (a) before solution dispersion is 187.6 [J / g], and the heat storage amount (b) after solution dispersion is 0.0 [J / g]. g], and the residual rate of the heat storage material was (b / a) 0.0%, and almost all the water-soluble heat storage material leaked from the heat storage microcapsules into the solvent of the slurry (see FIG. 14B). ).

It is a flowchart of an example of the manufacturing method of the thermal storage microcapsule of embodiment. It is drawing for demonstrating an example of the manufacturing method of the thermal storage microcapsule of embodiment. It is drawing for demonstrating an example of the manufacturing method of the thermal storage microcapsule of embodiment. It is drawing for demonstrating an example of the manufacturing method of the thermal storage microcapsule of embodiment. It is drawing for demonstrating an example of the manufacturing method of the thermal storage microcapsule of embodiment. It is drawing for demonstrating an example of the manufacturing method of the thermal storage microcapsule of embodiment. It is a flowchart of the manufacturing process of the thermal storage microcapsule of a comparative example. It is a figure which shows the thermal storage material residual amount when the thermal storage microcapsule of an Example and a comparative example is disperse | distributed to an aqueous medium. It is a figure which shows the relationship between the kind of latent-heat storage material, and melting | fusing point-heat of fusion. It is a figure which shows the thermal storage material residual amount when the thermal storage microcapsule which included the water-insoluble thermal storage material and the water-soluble thermal storage material was disperse | distributed to the aqueous medium.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thermal storage microcapsule 2 1st capsule wall 3 2nd capsule wall 11 Ca ion 12 Silicate ion 13 Phthaloyl dichloride 14 Diethylenetriamine 15 Calcium silicate 16 Polyamide resin 17 Toluene-2,4-diisocyanate

Claims (8)

A core substance comprising one or more water-soluble heat storage materials selected from the group consisting of sugars, sugar alcohols, inorganic salts, and inorganic salt hydrates;
A first capsule wall covering the core material;
And a second capsule wall made of a polymer material that covers the first capsule wall.   The heat storage microcapsule according to claim 1, wherein the first capsule wall is made of a composite material of an inorganic compound and an organic polymer compound.   The thermal storage micro of claim 2, wherein the inorganic compound is one or more selected from the group consisting of calcium silicate, magnesium silicate, zinc silicate, tin silicate, and iron silicate. capsule.   The heat storage microcapsule according to claim 2 or 3, wherein the organic polymer compound is a polyamide resin.   The said 2nd capsule wall consists of 1 type, or 2 or more types of polymer materials chosen from the group which consists of a polyurea, polyamide, a polyimide, a polyurethane, a polystyrene, and an acrylic resin, The any one of Claim 1 to 4 characterized by the above-mentioned. Thermal storage microcapsule.   A slurry obtained by dispersing the heat storage microcapsules according to any one of claims 1 to 5 in an aqueous solvent.   The slurry according to claim 6, further comprising one or more dispersants selected from the group consisting of polycarboxylic acid, vinyl acetate, maleic acid copolymer, polyvinyl alcohol, and fatty acid esters. A method for producing a heat storage microcapsule comprising: a core substance made of a water-soluble heat storage material; a first capsule wall covering the core substance; and a second capsule wall covering the first capsule wall,
Forming the aqueous phase by adding and mixing the water-soluble heat storage material in an aqueous solution containing silicate ions and polyamine; and
A step of preparing a W / O dispersion by mixing the aqueous phase and an oil phase containing a hydrocarbon solvent as a main component and heating and stirring;
The W / O dispersion is mixed with an inorganic ion solution containing one or more inorganic ions selected from the group consisting of Ca ions, Mg ions, Zn ions, Sn ions, and Fe ions. A first capsule wall formed by adding a hydrocarbon-based solution containing a dicarboxylic acid halide while heating and stirring to encapsulate the water-soluble heat storage material and forming a composite of polyamide resin and silicate. Obtaining a heat storage microcapsule precursor having,
Forming a second capsule wall made of a polymer material on the surface of the first capsule wall by mixing and stirring the heat storage microcapsule precursor and a monomer solution containing a monomer. The manufacturing method of the thermal storage microcapsule characterized by the above-mentioned.