TWI633228B - Non-woven fabric and non-woven fabric manufacturing method - Google Patents

Abstract

The present invention relates to a fluffy nonwoven fabric containing heat-expandable particles, and a fluffy nonwoven fabric improved in strength, particularly in terms of tensile strength and rubbing fastness, and a method for producing the same, in order to provide a heat-expandable particle which is less likely to fall off.

The method for producing a fluffy nonwoven fabric (100) according to the present invention includes the steps A and B; and the step A is to prepare a nonwoven fabric sheet (64) having a first surface and a second surface opposite to the first surface, the non-woven fabric The fiber sheet (64) contains a fluffy nonwoven fabric layer (105) containing expanded heat-expandable particles (160) and fibers (150) and constituting the first surface; At least the first surface of the nonwoven fabric sheet (64) is heated by a heat roll or a hot embossing roll to form at least the heat-expandable particles of the surface layer portion of the nonwoven fabric sheet (64) on the first surface side (160). ) Melting.

Description

Non-woven fabric and non-woven fabric manufacturing method

The present invention relates to a fluffy nonwoven fabric and a method of manufacturing the same.

In recent years, a non-woven fabric used as a paper towel, an absorbent article, or the like, a fluffy nonwoven fabric having a pulp fiber layer containing expanded heat-expandable particles has been discussed. As such a fluffy nonwoven fabric, Patent Document 1 proposes a non-woven fabric having a first layer on one surface, the first layer having a plurality of groove portions and containing fibers, and the second layer having the second surface. In the layer, the second layer contains expanded heat-expandable particles and fibers.

The non-woven fabric disclosed in Patent Document 1 is provided by providing the first layer to improve the dry tensile strength, the wet tensile strength, and the rubbing fastness of the nonwoven fabric, and by providing the second layer containing the heat-expandable particles. Non-woven fluffy.

[Advanced technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2013-209767

However, in the conventional fluffy nonwoven fabric containing the heat-expandable particles, since the heat-expandable particles are not dispersed in the fiber layer, they are not fixed. Therefore, when the nonwoven fabric is applied to paper towels and absorbent articles, thermal expansion is caused by vibration or the like during use. The particles are detached from the non-woven fabric. Further, in the conventional fluffy nonwoven fabric containing the heat-expandable particles, there is still room for improvement in strength, particularly in terms of tensile strength at break and rubbing fastness.

Accordingly, the present invention relates to a fluffy nonwoven fabric containing heat-expandable particles, and an object thereof is to provide a fluffy nonwoven fabric and a method for producing the same, which are disadvantageous in that peeling of heat-expandable particles is less likely to occur, and strength, particularly wet strength, and abrasion resistance are improved. degree.

A method for producing a fluffy nonwoven fabric according to the present invention, comprising: a step of preparing a nonwoven fabric sheet having a first surface and a second surface opposite to the first surface, wherein the nonwoven fabric sheet contains a fluffy nonwoven fabric layer, The fluffy nonwoven fabric layer contains expanded thermal expansion particles and fibers to form the first surface; and in step B, at least the first surface of the nonwoven fabric sheet is heated by a heat roll or a hot embossing roll to cause the aforementioned At least the heat-expandable particles of the surface layer portion on the first surface side of the nonwoven fabric sheet are melted.

In the method for producing a fluffy nonwoven fabric of the present invention, at least the first surface of the nonwoven fabric sheet is heated by a heat roller or a hot embossing roller, The heat-expandable particles located in the surface layer portion on the first surface side of the nonwoven fabric sheet are preferentially heated and melted, and the melt of the heat-expandable particles is at least partially filled between the fibers so that the fibers are bonded to each other to prevent the fibers from being bonded to each other. The heat-expandable particles in the interior of the nonwoven fabric sheet are detached from the outside of the nonwoven fabric sheet and the strength of the surface layer portion of the nonwoven fabric sheet is raised to function as a reinforcing film. Therefore, the steps after the step B, When the fluffy non-woven fabric is processed into various products, and when a product made of a fluffy non-woven fabric is used, even if vibration is imparted, the heat-expandable particles in the interior of the fluffy non-woven fabric are not easily peeled off, and the tensile strength (especially the stretching at the time of wetting) The surface strength such as the strength) and the rubbing fastness is excellent, and a fluffy nonwoven fabric having the above advantages can be obtained.

Further, in the manufacturing method of the present invention, at least the first surface of the nonwoven fabric sheet is heated by a heat roller or a hot embossing roller, so that the heat roller or the hot embossing roller is at least at least the aforementioned nonwoven fabric sheet. The surface of the first surface is heated by uniform contact for a predetermined period of time or more, and the thermally expandable particles located in the surface layer portion of the nonwoven fabric sheet can be preferentially heated and melted. Therefore, the above-described effects obtained by the melt of the heat-expandable particles can be obtained more reliably.

According to the method for producing a fluffy nonwoven fabric of the present invention, it is possible to obtain a fluffy nonwoven fabric in which the peeling of the heat-expandable particles is less likely to occur, and the strength, particularly the tensile strength at the time of wetting and the rubbing fastness, are improved.

1‧‧‧Nonwoven manufacturing equipment

1'‧‧‧Nonwoven manufacturing equipment

10‧‧‧Body formation

11‧‧‧Material supply head

12‧‧‧1st conveyor belt

13‧‧‧2nd conveyor belt

14‧‧‧Pressure dehydration department

15‧‧‧3rd handling conveyor

16‧‧‧1st raw material supply head

17‧‧‧ Round net (the second belt forming means)

18‧‧‧Drawing tank (the second belt raw material supply means)

20‧‧‧Drying Department

21‧‧‧Dry Roller (Yangke Dryer)

22‧‧‧1st drying roller (Yangke dryer)

23‧‧‧2nd drying roller (Yangke dryer)

30‧‧‧High Temperature Processing Department

31‧‧‧High temperature and high pressure steam supply device

32‧‧‧High temperature and high pressure steam suction device

40‧‧‧ Surface Heat Treatment Department

41‧‧‧First side heat treatment heat roller

42‧‧‧The second side heat treatment heat roller

50‧‧‧Winding Department

51‧‧‧ winding roller

61‧‧‧Initial belt

62‧‧‧After dehydration

63‧‧‧Down after drying (mixed sheets)

64‧‧‧After high temperature treatment (non-woven sheet)

65‧‧‧1st side heat treatment

66‧‧‧2nd side heat treatment

70‧‧‧High Pressure Water Treatment Department

71‧‧‧Attraction box

72‧‧‧High pressure water jet nozzle

81‧‧‧1st body

82‧‧‧2nd body

83‧‧‧Layered belt

84‧‧‧Laminating strip after dewatering

85‧‧‧1st dry laminated belt (mixed sheet)

86‧‧‧Laminated strip after high temperature treatment (non-woven sheet)

87‧‧‧Second dry laminated belt

88‧‧‧Laminated body after heat treatment

100‧‧‧ fluffy non-woven fabric

105‧‧‧Fluffed nonwoven fabric

110‧‧‧ Surface layer on the first side

120‧‧‧ Surface layer on the second side

130‧‧‧ Interior of non-woven fabric

140‧‧‧Melt of hot-expandable particles

150‧‧‧ fiber

160‧‧‧Hot-expanding particles

200‧‧‧ fluffy non-woven fabric

205‧‧‧ fluffy nonwoven fabric

210‧‧‧ Surface layer on the first side

220‧‧‧The interior of the fluffy nonwoven layer

230‧‧‧Non-floating nonwoven fabric

240‧‧‧Melt of hot-expandable particles

250‧‧‧ fiber

260‧‧‧heat-expanding particles

Fig. 1 is a schematic view showing a nonwoven fabric manufacturing apparatus used in a method of manufacturing a fluffy nonwoven fabric according to a first embodiment of the present invention.

Fig. 2 is a schematic cross-sectional view showing a fluffy nonwoven fabric obtained by a method for producing a fluffy nonwoven fabric according to a first embodiment of the present invention.

Fig. 3 is a schematic view showing a nonwoven fabric manufacturing apparatus used in a method of manufacturing a fluffy nonwoven fabric according to a second embodiment of the present invention.

Fig. 4 is a schematic cross-sectional view showing a fluffy nonwoven fabric obtained by a method for producing a fluffy nonwoven fabric according to a second embodiment of the present invention.

Fig. 5 (a) is an electron micrograph of a cross-sectional view of a fluffy nonwoven fabric according to an embodiment of the present invention, and Fig. 5 (b) is an electron micrograph of a first surface (face after heat treatment) of a fluffy nonwoven fabric of an embodiment of the present invention. .

Fig. 6(a) is an electron micrograph of a cross-sectional view of a fluffy nonwoven fabric of a comparative example of the present invention, and Fig. 6(b) is a first surface of a fluffy nonwoven fabric of a comparative example of the present invention (corresponding to the heat treatment of Example 1) Electron micrograph of the face).

Hereinafter, a method of manufacturing a fluffy nonwoven fabric according to a first embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a schematic view showing a nonwoven fabric manufacturing apparatus 1 used in a method of producing a bulky nonwoven fabric according to a first embodiment of the present invention.

As shown in FIG. 1, the nonwoven fabric manufacturing apparatus 1 is provided with a belt body. The forming portion 10 has a material supply head 11 for forming the initial belt body 61, a first conveyance belt 12, and a second conveyance belt 13; and a pressure dewatering portion 14 for dehydrating the initial belt body 61; The drying unit 20 has a drying roller 21 such as a Yankee dryer for drying the dehydrated belt 62, and the high temperature processing unit 30 includes a high temperature and high pressure steam supply device 31 and a high temperature and high pressure steam suction device 32. The high-temperature high-pressure steam supply device 31 includes a steam nozzle for expanding the heat-expandable particles dispersed in the dried belt 63 (that is, the mixed sheet) by the high-temperature treatment, and the high-temperature high-pressure steam suction device 32 is provided with a suction drum. The surface heat treatment unit 40 includes a first surface side heat treatment heating roller 41 and a second surface side heat treatment heating roller 42. The first surface side heat treatment heating roller is used to suck the water vapor supplied from the high-temperature high-pressure steam supply device 31. The 41st is for heat-treating the first surface of the strip 64 (that is, the non-woven fabric sheet) after the high-temperature treatment, and the second surface-side heat treatment heating roller 42 is for the first surface side heat treatment after the strip 65 2 sides for heat treatment; and The winding unit 50 has a winding roller 51 for winding the second surface-side heat-treated belt body 66. Further, in the present embodiment, the step from the initial tape forming step of the tape forming portion 10 to the high temperature processing step of the high temperature processing portion 30 described later corresponds to the step of the step A of the present invention.

A method of manufacturing a fluffy nonwoven fabric according to the first embodiment of the present invention can be carried out by using the nonwoven fabric manufacturing apparatus 1. Hereinafter, a method of manufacturing the fluffless nonwoven fabric of the present embodiment will be described in detail. First, a raw material (for example, a suspension in which fibers and heat-expandable particles are dispersed in water) containing fibers, heat-expandable particles, and water is supplied to a raw material supply head. 11. The tape raw material to be supplied to the raw material supply head 11 is supplied from the raw material supply head 11 to the conveyance belt of the first conveyance conveyance belt 12, and is deposited on the belt to form the initial belt body 61 (initial belt formation step) . Further, the conveyance belt of the first conveyance belt 12 is preferably a gas permeable support through which steam can pass, and for example, a wire mesh, felt, or the like can be used.

In the present invention, the fiber contained in the tape raw material is not particularly limited, and for example, a short fiber having a fiber length of 20 mm or less is preferably used. Examples of such short fibers include wood pulp such as chemical pulp such as conifers and hardwood trees, semi-chemical pulp or mechanical pulp; mercerized pulp or crosslinked pulp which has been chemically treated in the wood pulp; hemp and cotton, etc. Non-wood fiber; cellulose fiber containing regenerated fiber such as rayon fiber; synthetic fiber such as polyethylene fiber, polypropylene fiber, polyester fiber, polyamide fiber, etc., among which wood pulp, non-wood fiber or Cellulose fibers are preferred.

In the present invention, the thermally expandable particles contained in the raw material of the tape are not particularly limited as long as they are expandable by heat, and examples thereof include a shell portion made of a thermoplastic resin and sealed in the shell. Particles of a swelling agent such as a low-boiling solvent inside the part. The thermoplastic resin used for the shell portion of the heat-expandable particles may, for example, be a copolymer such as vinylidene chloride, acrylonitrile, acrylate or methacrylate. Examples of the low boiling point solvent used for the expansion agent of the heat-expandable particles include isobutane, pentane, petroleum ether, hexane, a low boiling halogenated hydrocarbon, and methyl decane.

Moreover, the ratio of the heat-expandable particles contained in the above-mentioned tape raw material The example is not particularly limited, and is preferably 1 to 40 parts by mass, more preferably 3 to 20 parts by mass, per 100 parts by mass of the fiber. When the ratio of the heat-expandable particles contained in the tape raw material is 1 part by mass or more based on 100 parts by mass of the fiber, the heat-expandable particles can be sufficiently expanded in the high-temperature treatment step described later. In addition, when the ratio of the heat-expandable particles contained in the tape raw material is 40 parts by mass or less to 100 parts by mass of the fiber, the expansion of the expandable particles can be efficiently performed in the high-temperature treatment step described later.

In the present invention, the average particle diameter before expansion of the heat-expandable particles is preferably 5 to 30 μm, more preferably 8 to 14 μm. When the heat-expandable particles are heated to a temperature higher than the expansion starting temperature, the shell portion composed of the thermoplastic resin is softened, and the low-boiling solvent contained in the shell portion is vaporized, and the volume is expanded to become larger hollow heat-expandable particles. The volume of the thermally expandable particles after expansion is preferably 20 to 125 times, more preferably 50 to 80 times, as compared with the volume of the heat-expandable particles before expansion. The heat-expandable particles are not particularly limited, and for example, Matsumoto Microsphere (F-36, F-30D, F-30GS, F-20D, F-50D, F-80D) (made by Matsumoto Oil & Fats Co., Ltd.) can be used. Expancel (WU, DU) (made in Sweden, distributor Japan Fillite (share)) and so on.

Further, in the present invention, in order to allow the heat-expandable particles to be easily fixed to the fibers contained in the tape raw material, the tape raw material may be contained, for example, Filex RC-104 (manufactured by Meisei Chemical Industry Co., Ltd.), a cationically modified acrylic polymer. ), a fixing agent such as FilexM (manufactured by Mingcheng Chemical Industry Co., Ltd., acrylic copolymer). Furthermore, the above-mentioned tape raw material may also contain an anionic, nonionic, cationic or amphoteric utilization improving agent, sizing Various additives such as agents.

In the present embodiment, the initial belt body 61 formed on the conveyance belt of the first conveyance belt 12 and the upper surface of the initial belt body 61 (opposite to the surface in contact with the conveyance belt of the first conveyance belt 12) The conveyance belt (for example, the conveyance felt or the like) of the second conveyance belt 13 that is supplied to the side is transferred to the conveyance belt of the first conveyance belt 12, and is transferred to the conveyance belt. The conveyance belt of the second conveyance belt 13 is conveyed in a predetermined conveyance direction (MD direction). Further, the initial belt body 61 is a heat-expandable particle dispersed in the fiber.

Next, as shown in FIG. 1, the initial belt body 61 on the conveyance belt of the second conveyance belt 13 is conveyed to the pressurization dewatering part 14. In the pressurization and dewatering unit 14, the first conveyance belt 61 and the third conveyance belt supplied from the upper surface of the initial belt body 61 (the surface opposite to the surface on the side of the conveyance belt of the second conveyance belt 13) are supplied. The conveyance belt of 15 (for example, a felt for conveyance, etc.) is compressed by the conveyance belt of the said 2nd conveyance conveyance belt 13, and the moisture of the initial belt body 61 is dehydrated, and it transfers to the said conveyance conveyance belt 15 Carrying belt (dehydration step). Further, the dehydrated belt (dewatered belt 62) to be transferred onto the conveyance belt of the third conveyance belt 15 is then dried by the drying roller 21 of the drying unit 20 as shown in FIG. The conveyance belt of the third conveyance belt 15 is nipped and pressurized, and is transferred onto the surface of the drying roller 21.

In the present embodiment, the drying roller 21 heats the strip 62 while being conveyed in the MD direction, and dries the dehydrated strip 62 (drying step). As the drying roller 21, for example, a Yankee dryer or the like is used. before The drying roller 21 includes a rotating cylindrical dryer that heats the surface to a predetermined temperature (for example, 105 ° C) by steam or the like, and attaches the dehydrated tape body 62 to the surface of the rotating cylindrical dryer. The dehydrated tape body 62 is dried while being conveyed in the MD direction. Further, the temperature of the drying roll is preferably a temperature below the melting point of the fibers (particularly heat-fusible fibers) in the belt (for example, less than 110 ° C). If the temperature of the drying roll is higher than the melting point of the fibers in the belt, the fibers are thermally welded to each other in the drying step, so that the strength of the belt becomes too strong, so that the heat-expandable particles are hindered in the high-temperature treatment step described later. The situation of expansion.

The drying roller 21 is configured to dry the dehydrated tape body 62, and the moisture content of the dried tape body (the dried tape body 63) is preferably from 10 to 80%, more preferably from 20 to 80%, more preferably. It is 20~60%. Here, the water content refers to the ratio of the mass of water contained in the belt when the dry mass of the belt is 100%.

When the moisture content of the belt 63 after drying is smaller than 10%, the hydrogen bonding force between the fibers in the belt body is excessively strong, and in the high-temperature treatment step described later, the thermal expansion property is caused by high-temperature high-pressure steam. The expansion of the particles is hindered by the hydrogen bonding between the aforementioned fibers. On the other hand, when the moisture content of the belt 63 after drying is larger than 80%, in the high-temperature treatment step described later, most of the heat imparted by the high-temperature high-pressure steam is used for the moisture in the belt. Evaporation, and there is a case where sufficient heat cannot be imparted to the heat-expandable particles. Further, in the high-temperature treatment step described later, the energy required to dry the dried belt 63 to a predetermined moisture content or less may increase.

Then, as shown in FIG. 1, the dried belt body 63 is conveyed to the high temperature processing unit 30, and moves on the mesh-like outer peripheral surface of the cylindrical suction drum of the high-temperature high-pressure steam suction device 32. At this time, the high-temperature high-pressure steam from the steam nozzle of the high-temperature high-pressure steam supply device 31 disposed above the outer peripheral surface of the suction drum is applied to the upper surface of the dried belt 63 (the second surface side of the belt) ) Spray (high temperature treatment step). A suction device is provided in the suction drum, and the water vapor sprayed from the steam nozzle is transmitted through the dried belt 63 and sucked by the suction device. The high-temperature and high-pressure water vapor can instantaneously heat the strip to a temperature higher than the thermal expansion starting temperature of the thermally expandable particles while evaporating the water in the strip, thereby preventing the moisture content in the strip from becoming too low. Hydrogen bonding is exhibited, and in addition, the aforementioned heat-fusible particles can be heated without heat fusion of fibers (especially heat-fusible fibers). The heat-expandable particles dispersed in the dried belt 63 are instantaneously heated to a temperature higher than the thermal expansion start temperature of the heat-expandable particles by the heat of the high-temperature and high-pressure steam, and the dried belt 63 is dried. Fluffy, for example, increased by more than 30%. Further, in the present embodiment, the high-temperature treated tape 64 having a single-layer structure composed of a bulky nonwoven fabric layer corresponds to the nonwoven fabric sheet of the present invention.

In the present invention, the high-temperature high-pressure steam used in the high-temperature treatment step may be water vapor composed of 100% water or water vapor (humid hot air) containing other gases such as air. When such a moist hot air or water vapor is used as the heating means of the heat-expandable particles, when a high-temperature liquid is used, it is difficult to cause the thermally expandable particles to fall off due to the pressure of the high-temperature fluid.

In addition, the temperature of the water vapor is not particularly limited as long as it is a temperature at which the heat-expandable particles can be expanded, and may be appropriately selected depending on the type of the heat-expandable particles to be used, and it is preferred that the shell portion of the heat-expandable particles is softened and the heat-expandable particles are expanded. The temperature (for example, 140 ° C) above the initial temperature (the expansion starting temperature of the heat-expandable particles). In addition, since the heat-expandable particles shrink due to reaching a predetermined temperature or higher, the temperature of the water vapor is preferably a temperature at which the heat-expandable particles start to shrink (the shrinkage start temperature of the heat-expandable particles). As such a temperature, for example, a temperature in the range of 120 to 190 ° C can be mentioned. Further, since the temperature of the water vapor is related to the vapor pressure of the steam described later, it can be easily calculated by measuring the vapor pressure of the steam.

In the present embodiment, the structure and arrangement of the steam nozzles disposed above the suction drum are not particularly limited as long as sufficient heat can be applied to the dried belt 63 to expand the heat-expandable particles. Construction and configuration form. For example, the steam nozzle may be configured such that a plurality of nozzle holes are arranged in four rows or more in the MD direction and the CD direction orthogonal to the MD direction.

Further, the diameter of the nozzle hole of the vapor nozzle is not particularly limited, but is preferably 100 to 250 μm. When the pore diameter of the nozzle hole is smaller than 100 μm, the heat energy applied to the dried belt body 63 is insufficient, and the heat-expandable particles may not be sufficiently heated. When the pore diameter of the steam nozzle is larger than 250 μm, the heat energy applied to the dried belt body 63 is excessively large, and the belt 63 after the drying is damaged. And the pitch of the nozzle holes of the steam nozzle (the distance between the centers of the nozzle holes adjacent to the CD direction) There is no particular limitation, and it is preferably 0.5 to 1.0 mm. When the hole pitch of the nozzle hole is smaller than 0.5 mm, the pressure resistance of the vapor nozzle is lowered or broken. When the hole pitch of the nozzle holes is larger than 1.0 mm, there is a case where the belt 63 is insufficiently heated in the area after the drying. If such a region where the heating is insufficient occurs after the drying of the tape 63, there is a possibility that the tape 64 (non-woven fiber sheet) is largely fluffy and uneven after the high-temperature treatment after the high-temperature treatment step.

In the present embodiment, the vapor pressure of the water vapor injected from the steam nozzle of the high-temperature high-pressure steam supply device 31 is not particularly limited, but is preferably 0.2 to 1.5 MPa. When the vapor pressure of the water vapor is less than 0.2 MPa, it is impossible to sufficiently impart high-temperature and high-pressure steam to the thermally expandable particles dispersed in the belt, and the thermally expandable particles are not sufficiently heated. Further, if the vapor pressure of the water vapor is larger than 1.5 MPa, there is a case where the opening of the belt is broken, the belt is broken, or the belt is flying.

Further, in the present embodiment, the dry belt member 63 conveyed to the high temperature processing unit 30 is sucked to the suction drum by the suction device of the suction drum built in the high temperature and high pressure water vapor suction device 32. on the surface. The attraction of the suction drum is not particularly limited, but is preferably -5 to -12 kPa. If the suction force of the suction drum is smaller than -5 kPa, the water vapor sprayed from the steam nozzle cannot be sucked up, and the spray is generated. Further, if the suction force of the suction drum is larger than -12 kPa, there is a case where the fibers in the suction drum are detached.

In the present embodiment, the distance between the tip end of the steam nozzle of the high-temperature high-pressure steam supply device 31 and the surface of the belt 63 after drying is not There are special restrictions, preferably 1.0 to 10 mm. If the distance is smaller than 1.0 mm, there is a case where the belt is opened, the belt is broken, or the belt is flying. In addition, when the distance is larger than 10 mm, the high-temperature high-pressure water vapor is dispersed, and the heat-expandable particles dispersed in the belt cannot be efficiently supplied with heat.

In the present invention, the water content of the tape (non-woven fabric sheet) after the high-temperature treatment step is preferably 40% or less, more preferably 30% or less. When the water content is greater than 40%, in the heat treatment step described later, most of the heat applied to the belt is used for evaporation of moisture in the belt, and there is a case where sufficient heat cannot be applied to the belt, and further It is difficult to make the moisture content of the tape after the heat treatment of the first surface 5% or less. Therefore, the water content of the tape (non-woven fabric sheet) after the high-temperature treatment step is 40% or less, and the heat loss as described above can be reduced, and the tape (non-woven fabric sheet) after the high-temperature treatment step can be obtained. Heat efficiently.

In the present embodiment, the strip 64 is subjected to the high-temperature treatment in the high-temperature treatment step, and then transferred to the first surface-side heat treatment heat roller 41 of the surface heat treatment portion 40 as shown in FIG. 1 . The first surface heat treatment heat roller is configured to heat the first surface of the high temperature treated strip 64 while the high temperature treated strip 64 is transported in the MD direction, so as to be located on the first surface of the high temperature treated strip 64. The thermally expandable particles after expansion of the surface layer portion on the side are melted (first surface side heat treatment step). In the present specification, the "surface layer portion" refers to a region within 15% of the entire thickness, for example, within a distance of 0.1 mm from the surface, based on the respective surfaces of the sheet. The first surface side heat treatment heat roller 41 has a rotating cylindrical shape The heat roller heats the surface to a predetermined temperature, preferably to a temperature higher than a melting point of the thermoplastic resin constituting the shell portion of the heat-expandable particles, and more preferably to a shell portion constituting the heat-expandable particles. At a temperature equal to or higher than the melting point of the thermoplastic resin and higher than the melting point by 10 ° C (for example, 200 ° C), the high temperature-treated tape 64 is attached to the surface of the heat roller and conveyed in the MD direction while the high temperature is applied. The first surface of the belt body 64 is heated after the treatment. In this case, the first surface of the strip 64 (non-woven fabric sheet) after the high-temperature treatment is equal to or higher than the melting point of the thermoplastic resin constituting the shell portion of the heat-expandable particles and 10 ° C higher than the melting point of the thermoplastic resin. When the temperature is lower than the temperature, the heat-expandable particles in the surface layer portion on the first surface side of the strip body 64 after the high-temperature treatment can be more reliably melted, and heat of the melting point or higher of the thermoplastic resin is hardly transmitted to The inside of the belt body 64 after the high-temperature treatment can prevent the heat-expandable particles contained in the inside from being melted, so that the bulky structure of the belt body 64 after the high-temperature treatment can be more reliably maintained. In the present specification, the term "first surface" means a surface formed by a layer containing thermally expandable particles among two surfaces of the nonwoven fabric, and "second surface" means two of the nonwoven fabrics. Among the faces, the other side opposite to the first surface described above. Therefore, in the first embodiment, the fluffy nonwoven fabric is composed of a single layer of a fluffy nonwoven fabric layer, and any of the fluffy nonwoven fabric layers can be used as the "first surface", but the second embodiment will be described later. The fluffy nonwoven fabric is composed of a layered body of a fluffy nonwoven fabric layer containing heat-expandable particles and a fiber layer (non-fluffy nonwoven fiber layer) containing no heat-expandable particles, and the aforementioned fluffy nonwoven fabric layer With the aforementioned non-fluffy non-woven fibers The surface on the opposite side of the layer serves as the "first surface".

In the present embodiment, the first surface of the strip 64 (non-woven fabric sheet) after the high-temperature treatment is heated by the first surface-side heat treatment heat roller 41 (heat roller). The heat-treating heat roller 41 heats the surface of the strip body 64 after the high-temperature treatment for a predetermined period of time or more, and can heat the surface layer portion on the first surface side of the strip body 64 after the high-temperature treatment. The particles are preferentially heated to melt.

Further, in the present invention, the water content after the first surface side heat treatment step is preferably 5% or less, more preferably 3% or less. When the water content is greater than 5%, in the second surface side heat treatment step to be described later, most of the heat applied to the belt body is used for evaporation of moisture in the belt body, and the belt body cannot be provided with sufficient heat. situation. Therefore, the water content of the belt after the first surface side heat treatment step is 5% or less, and the heat loss as described above can be reduced, and the belt body after the first surface side heat treatment step can be efficiently heated. Further, in the second surface side heat treatment step which will be described later, when a heat roller or a hot embossing roller is used as the heating means, since a small-sized roller can be used, it is also possible to reduce the size of the manufacturing equipment and save energy.

In the first embodiment of the present invention, the belt body (the belt body 65 after the first surface side heat treatment) is subjected to the heat treatment roller for heat treatment of the first surface side as shown in Fig. 1 . 41 is peeled off and reversed, and is transferred to the second surface side heat treatment heat roller 42 disposed on the downstream side in the MD direction of the first surface side heat treatment heat roller 41. The second surface side heat treatment heat roller 42 is configured to heat the first surface side After the first belt-side heat treatment, the second surface of the belt 65 is heated, and the surface layer portion on the second surface side of the belt 65 after the first surface side heat treatment is expanded. The heat-expandable particles are melted (the second surface side heat treatment step). The second surface side heat treatment heat roller 42 includes a rotating cylindrical heat roller that heats the surface to a predetermined temperature, preferably to a temperature higher than a melting point of the thermoplastic resin constituting the shell portion of the heat-expandable particles. The temperature is more preferably a temperature (for example, 200 ° C) which is heated to a temperature equal to or higher than a melting point of the thermoplastic resin constituting the shell portion of the heat-expandable particles and higher than the melting point by 10 ° C (for example, 200 ° C), and the first surface side heat treatment is carried out. The body 65 is attached to the surface of the heat roller and conveyed in the MD direction, and the second surface of the belt 65 after the first surface side heat treatment is heated. In this case, the second surface of the strip 65 after the heat treatment of the first surface side is equal to or higher than the melting point of the thermoplastic resin constituting the shell portion of the heat-expandable particles and 10 ° C higher than the melting point of the thermoplastic resin. When the temperature is heated, the thermally expandable particles in the surface layer portion on the second surface side of the strip 65 after the first surface side heat treatment can be more reliably melted, and heat of the melting point or higher of the thermoplastic resin is hardly transmitted to Since the inside of the belt body 65 after the first surface side heat treatment is formed, the heat-expandable particles contained in the inside can be prevented from being melted. Therefore, the bulk structure of the belt body 65 after the first surface side heat treatment can be more reliably maintained.

Further, in the present invention, the means for heating the first surface of the belt (the nonwoven fabric sheet) after the high-temperature treatment step or the second surface of the belt after the heat treatment step of the first surface side is capable of heating the surface of the sheet. There is no particular limitation, and a hot embossing roll is also suitable in addition to the above-mentioned heat roller. As When a heating roll or a hot embossing roll is used as the heating means on the surface of the non-woven fiber sheet, the heat roll or the hot embossing roll can be heated by uniformly contacting the surface of the nonwoven fabric sheet for a certain period of time or longer. The heat-expandable particles located in the respective surface layer portions of the nonwoven fabric sheet are preferentially heated and melted, so that the surface strength of the bulky nonwoven fabric obtained by the melt of the heat-expandable particles can be preferentially improved, in particular, the rubbing fastness. .

On the other hand, as a heating means for the surface of the nonwoven fabric sheet, for example, in the case of using hot air, the heat-expandable particles of the nonwoven fabric sheet (especially in the surface layer portion) may be sprayed, and a high-temperature atmosphere is used. In the case of a greenhouse, heat is transferred to the inside of the non-woven fabric sheet, and the soft and comfortable skin touch (soft feeling) of the non-woven fabric sheet is damaged by the presence of the internally expanded heat-expandable particles.

Further, as the heat roller used for the heating means on the surface of the nonwoven fabric sheet, for example, a Yankee dryer can be used. In the present invention, the Yankee dryer used as a dryer can be generally used as a heating means for the surface of the nonwoven fabric sheet. Therefore, it is not necessary to provide a special-stage heat roller device as a manufacturing device for a fluffy nonwoven fabric, and it is possible to suppress equipment investment. increase.

Then, as shown in FIG. 1 , the belt body (the belt body 66 after the second surface side heat treatment) that has passed through the second surface side heat treatment step is conveyed toward the winding portion 50 and wound around the winding roller 51 . Further, in the present embodiment, the first surface side heat treatment step and the second surface side heat treatment step correspond to the step B of the present invention.

A schematic cross-sectional view of the fluffy nonwoven fabric thus obtained is shown in Fig. 2. As shown in Fig. 2, the table of the fluffy non-woven fabric 100 on the first side In the layer portion 110 and the surface layer portion 120 on the second surface side, the melt 140 of the heat-expandable particles is at least partially filled between the fibers 150 to bond the fibers 150 to each other, and the melt 140 of the heat-expandable particles serves as a reinforcing film. The function of preventing the heat-expandable particles 160 of the inner portion 130 (i.e., between the two surface portions) in which the non-woven fabric sheet (the fluffy nonwoven fabric layer 105) is present from falling off from the both sides of the nonwoven fabric sheet, and Since the surface strength of the nonwoven fabric sheet is increased, the heat-expandable particles 160 of the inner portion 130 of the bulky nonwoven fabric 100 are present even when vibration is imparted to the step of processing the bulky nonwoven fabric 100 to various products and the use of the product using the bulky nonwoven fabric 100. It is also not easy to fall off, and is excellent in strength, particularly in tensile strength and rubbing fastness.

Next, a method of manufacturing a fluffy nonwoven fabric according to a second embodiment of the present invention will be described. Fig. 3 is a schematic view showing a nonwoven fabric manufacturing apparatus 1' used in the method for producing a bulky nonwoven fabric according to the second embodiment of the present invention.

As shown in Fig. 3, the nonwoven fabric manufacturing apparatus 1' includes a belt forming portion 10 having a material supply head 16, a first conveyance belt 12, and a second conveyance belt 13 for forming the first belt 81. a high-pressure water flow processing unit 70 that forms a groove portion on the surface of the first belt body 81, a round net 17 for forming the second belt body 82, and a papermaking tank 18; and a pressurization dewatering unit 14 for the aforementioned The laminated belt body 83 in which the belt body 81 and the second belt body 82 are laminated is dehydrated; the drying unit 20 has a first drying roller 22 and a second drying roller 23 for dewatering the laminated belt body 84 to 2 The stage is dried; the high temperature processing unit 30 has a high temperature and high pressure steam supply device 31 and a high temperature and high pressure water vapor suction device 32, and the high temperature and high pressure The steam supply device 31 includes a steam nozzle for expanding the heat-expandable particles dispersed in the second belt body of the first dry laminated belt body 85 by high-temperature treatment, and the high-temperature high-pressure steam suction device 32 is provided. The suction drum is for sucking the water vapor supplied from the high-temperature high-pressure steam supply device 31, and the surface heat treatment portion 40 is provided with a first surface-side heat treatment heating roller 41 for laminating the strip body 86 after the high-temperature treatment (that is, not woven The fiber sheet is dried by the second drying roll 23, and the first surface (surface on the second tape side) of the second dried laminated tape body 87 is heat-treated; and the winding portion 50 is provided with a winding roller. 51 is used to wind the laminated strip 88 after heat treatment. Further, in the present embodiment, the step from the first tape forming step of the tape forming portion 10 to the second drying step by the second drying roller 23 will be described as a step of the step A of the present invention.

The nonwoven fabric manufacturing apparatus 1' can be used to carry out the method for producing a bulky nonwoven fabric according to the second embodiment of the present invention. Hereinafter, a method of manufacturing the fluffless nonwoven fabric of the present embodiment will be described in detail. First, a first tape raw material containing fibers and water (for example, a fiber suspension in which fibers are dispersed in water) is supplied to the raw material supply head 16. As shown in Fig. 3, the tape raw material supplied to the raw material supply head 16 is supplied from the raw material supply head 16 to the conveyance belt of the first conveyance conveyance belt 12, and is deposited on the belt to form the first belt body 81 ( The first tape forming step)). Further, the conveyance belts of the first conveyance belt 12 and the second conveyance belt 13 can be used in the same manner as in the first embodiment described above.

In the present embodiment, the fibers contained in the first tape raw material can be used in the same manner as the user of the tape raw material according to the first embodiment.

In the present embodiment, as shown in FIG. 3, the first belt body 81 formed on the conveyance belt of the first conveyance belt 12 is conveyed in the conveyance direction (MD direction) while passing through the high-pressure water flow nozzle 72 and Between the suction tanks 71, the high-pressure water flow nozzles 72 are disposed in the high-pressure water flow nozzles 72 of the high-pressure water flow processing unit 70 above the conveyance belts of the first conveyance conveyor 12, and the suction tanks 71 are disposed below the conveyance belts. The position opposite to the high pressure water flow nozzle 72 described above. In the passage of the first belt 81, the high-pressure water jet nozzle 72 jets a plurality of high-pressure water streams which are arranged in the width direction (CD direction) of the first belt body 81 toward the first belt body 81, and forms on the surface of the first belt body 81. The plurality of groove portions extending in the MD direction, on the other hand, the suction box 71 sucks the water sprayed from the high-pressure water jet nozzle 72 and collects it (high-pressure water flow processing step). Further, the diameter and arrangement of the nozzle holes of the high-pressure water jet nozzle 72 can be appropriately set in accordance with the form of the groove portion to be formed, the processing efficiency, and the like.

In the high-pressure water flow processing step, the first belt body 81 forms a plurality of groove portions on the surface by the high-pressure water flow, and the fibers in the first belt body 81 are entangled with each other to increase the strength of the belt body. In the high-temperature treatment step, even if the high-temperature high-pressure steam is sprayed onto the first dried laminated belt body 85, it is difficult to cause the opening of the belt, the belt to be broken, or the belt to fly. Further, even when the reinforcing agent or the like is not added to the first tape raw material, the tensile strength at the time of wetting the first tape body 81 can be increased.

In the present embodiment, as shown in FIG. 3, the first belt body 81 subjected to the high-pressure water flow treatment step is connected to the upper surface of the first belt body 81 (and the conveyance belt of the first conveyance belt 12). Opposite side The conveyance belt of the second conveyance belt 13 (for example, the conveyance felt or the like) and the conveyance belt of the first conveyance belt 12 are clamped and pressurized, and then transferred to the second conveyance. The conveyance belt of the conveyor belt 13 is conveyed in the conveyance direction (MD direction). Then, the first belt body 81 is laminated on the surface opposite to the surface in contact with the conveyance belt, and the laminated belt body 83 is formed.

Here, the second tape 82 is produced as follows. First, a second tape raw material containing fibers, heat-expandable particles, and water is supplied to the papermaking tank 18 (second tape raw material supply means) in which the rotary net 17 (second tape forming means) is provided (for example, a suspension in which fibers and heat-expandable particles are dispersed in water, etc.). In addition, the fiber and the heat-expandable particle contained in the second tape raw material can be the same as those used in the tape raw material of the first embodiment. In addition, the content ratio of the fibers and the heat-expandable particles contained in the second tape raw material, and the additives which may be contained in the second tape raw material are the same as those in the first embodiment.

Further, as shown in FIG. 3, the second tape raw material supplied into the papermaking groove 18 is sucked into the rotating circular net 17, and a sheet-like second tape body is formed on the surface of the circular net 17. 82 (second strip forming step). Further, the second belt body 82 is a heat-expandable particle dispersed in the fiber. As shown in FIG. 3, the second belt body 82 thus formed is superposed on the surface of the first belt body 81 conveyed by the second conveyance belt 13 by the rotation of the circular net 17 (and the 2, the surface of the conveyor belt 13 opposite to the surface on which the conveyance belt is in contact with each other is compressed, and a laminated belt body in which the first belt body 81 and the second belt body 82 are laminated is formed. 83 (layered belt forming step).

As shown in FIG. 3, the laminated tape body 83 formed on the conveyance belt of the second conveyance conveyor 13 is conveyed to the pressurization dewatering part 14. In the pressurization and dewatering unit 14, the conveyance belt of the third conveyance belt 15 is supplied from the upper surface of the laminated belt body 83 (the surface opposite to the surface on the side of the conveyance belt of the second conveyance belt 13). (for example, a transfer felt or the like) and the conveyance belt of the second conveyance belt 13, the laminated belt body 83 is compressed, the moisture in the laminated belt body 83 is dehydrated, and the conveyance belt 15 is transferred to the third conveyance belt 15 Carrying belt (dehydration step). Further, the dewatered laminated belt body 84 transferred onto the conveyance belt of the third conveyance belt 15 is then conveyed by the first drying roller 22 of the drying unit 20 and the third conveyance conveyance as shown in FIG. The conveyance belt of the belt 15 is nipped and pressurized, and is transferred onto the surface of the first drying roller 22.

In the first embodiment, the first drying roll 22 heats the dewatered laminated belt body 84 while being conveyed in the MD direction, and the dewatered laminated belt body 84 is dried (first drying step). As the first drying roller 22, for example, a Yankee dryer or the like is used. The first drying roll 22 includes a rotary cylindrical dryer that heats the surface to a predetermined temperature (for example, 105 ° C) by steam or the like, and the dewatered laminated belt body 84 is attached to the rotating cylindrical dryer. The surface of the dewatered laminated tape body 84 is dried while being conveyed in the MD direction. Further, the preferred temperature of the first drying roll 22 is the same as that of the drying roll of the first embodiment.

The first drying roller 22 is configured to dry the dehydrated laminated tape body 84 into a moisture after drying (the first dried laminated tape body 85). The ratio is preferably 10 to 80%, more preferably 20 to 80%, and even more preferably 20 to 60%. When the water content of the laminated body 85 after the first drying is less than 10%, the hydrogen bonding force between the fibers in the tape becomes too strong, and in the high-temperature treatment step described later, there is a high-temperature high-pressure water vapor. The expansion of the heat-expandable particles is hindered by hydrogen bonding between the fibers. On the other hand, when the moisture content of the first dry layered belt body 85 is larger than 80%, in the high-temperature processing step described later, most of the heat imparted by the high-temperature high-pressure steam is used in the belt. The evaporation of moisture does not allow sufficient heat to be imparted to the thermally expandable particles. Further, in the high-temperature treatment step described later, the energy required to dry the first dried laminated belt body 85 to a predetermined moisture content or less may increase.

Then, as shown in FIG. 3, the first dry laminated belt body 85 is conveyed to the high temperature processing unit 30, and moves on the mesh-like outer peripheral surface of the cylindrical suction drum of the high-temperature high-pressure steam suction device 32. At this time, the high-temperature high-pressure steam from the steam nozzle of the high-temperature high-pressure steam supply device 31 disposed above the outer peripheral surface of the suction drum is applied to the upper surface of the first dry laminated belt body 85 (the first surface of the belt body) The side surface (i.e., the surface on the second belt side) is sprayed (high temperature treatment step). A suction device is provided in the suction drum, and the water vapor sprayed from the steam nozzle is transmitted through the first dry laminated belt body 85 and sucked by the suction device. Further, the high-temperature high-pressure steam used in the high-temperature treatment step can be used in the same manner as in the first embodiment described above.

Further, by the heat of the high-temperature and high-pressure water vapor, the second belt body dispersed from the first dry laminated belt body 85 is dispersed. The heat-expandable particles in the fiber layer are evaporated while being heated to a temperature higher than the thermal expansion start temperature of the heat-expandable particles, and the fiber layer from the second tape is bulky, for example, raised. More than 30%, forming a layer of fluffy nonwoven fabric. Further, in the present embodiment, the fiber layer (a bulky nonwoven fiber layer) from the second tape containing the thermally expandable particles after expansion and the fiber layer from the first tape containing no heat-expandable particles (not fluffy) The woven fiber layer) is a layered belt after high temperature treatment, which corresponds to the nonwoven fabric sheet of the present invention.

Further, after the high-temperature treatment after the high-temperature treatment step, the laminated tape body 86 (non-woven fiber sheet) is derived from the fiber layer (non-fluffy nonwoven fiber layer) of the first tape body containing no heat-expandable particles, as described above. a layer of increased strength by a high-pressure water flow treatment step, and a fiber layer (a fluffy nonwoven fiber layer) derived from a second belt containing expanded heat-expandable particles, which is unwound by expansion of heat-expandable particles. A layer in which the strength of the fiber layer is lowered, but the bulk (thickness) is increased. Thus, a fluffy and high-strength nonwoven fiber sheet can be formed by providing a non-bulft non-woven fiber layer having high strength and a bulky nonwoven fiber layer having low strength and high bulkiness. Further, in the present invention, it is preferable that the nonwoven fabric sheet has a thickness of the bulky nonwoven fabric layer of at least twice the thickness of the non-fluffy nonwoven fabric layer. If the thickness of each fiber layer is such a relationship, it is possible to realize a nonwoven fabric sheet having a balance of bulkiness and strength.

Further, in the present invention, one or more other layers may be provided between the bulky nonwoven fabric layer and the non-fluffy nonwoven fabric layer. In this case, by providing the aforementioned fluffy nonwoven fabric layer and the foregoing A non-fluffy, non-woven fibrous layer that achieves a fluffy and strong non-woven fibrous sheet.

In the present embodiment, the temperature of the high-temperature high-pressure steam used in the high-temperature processing step, the structure and arrangement of the steam nozzle, the vapor pressure of the steam sprayed from the steam nozzle, the suction force of the suction drum, and the like are the same as the first The embodiment is the same.

Further, the moisture content of the laminated belt body 86 (non-woven fabric sheet) after the high-temperature treatment after the high-temperature treatment step is preferably 40% or less, more preferably 30% or less. When the water content is greater than 40%, in the second drying step and the heat treatment step, which will be described later, most of the heat applied to the laminated belt body is used for evaporation of moisture in the belt body, and the laminated belt body cannot be sufficiently provided. In the case of the heat, the moisture content of the laminated tape body (the second dried laminated tape body 87) after the second drying step described later is less likely to be 5% or less. Therefore, the moisture content of the laminated tape body 86 after the high-temperature treatment is 40% or less, and the heat loss as described above can be reduced, and the high-temperature-treated laminated tape body 86 can be efficiently heated. Further, in the first surface side heat treatment step to be described later, in the case of the heat roller or the hot embossing roller used as the heating means, a small-sized roller can be used, and therefore, it is possible to reduce the size and energy saving of the manufacturing equipment.

In the present embodiment, as shown in FIG. 3, after the high temperature treatment in the high temperature treatment step, the layered belt 86 is laminated, and then transferred to the second drying roller 23. In the second drying roll 23, the laminated tape body 86 after the high temperature treatment is dried to a moisture content of 5% or less (second drying step). For the second drying roller 23, for example, a Yankee dryer is used. The second drying roller 23 includes a rotating cylinder that heats the surface to a predetermined temperature (for example, 160 ° C or the like) by steam or the like. In the drying machine, the high-temperature-treated laminated tape body 86 is adhered to the surface of the rotating cylindrical dryer, and the high-temperature-treated laminated tape body 86 is dried while being conveyed in the MD direction. In the second drying roll 23, the water content of the belt (the second dry laminated belt 87) after drying the high-temperature-treated laminated belt body 86 is 5% or less, and more preferably 3% or less.

Then, as shown in FIG. 3, the second layer of the laminated tape body 87 after the second drying step is transferred to the first surface side heat treatment heat roller 41 of the surface heat treatment portion 40. The first surface-side heat treatment heat roller is conveyed in the MD direction while the second dry laminated belt body 87 is conveyed, and the first surface of the second dried laminated belt body 87 (that is, the expanded thermal expansion property) The surface of the fluffy nonwoven fabric layer of the particles is heated to melt the thermally expandable particles that have been expanded in the surface layer portion on the first surface side of the second dry laminated strip body 87 (first surface side heat treatment step).

In the present embodiment, the type, structure, set temperature, function, and the like of the first surface side heat treatment heat roller 41 are the same as those of the first embodiment.

Then, as shown in FIG. 3, the belt body (the heat-treated laminated belt body 88) subjected to the first surface side heat treatment step is conveyed toward the winding portion 50 and wound around the winding roller 51. Further, in the present embodiment, the first surface side heat treatment step corresponds to the step B of the present invention.

A cross-sectional view of the fluffy nonwoven fabric thus obtained is shown in Fig. 4. As shown in FIG. 4, the fluffy nonwoven fabric 200 is prevented from being scattered in the non-woven fabric layer (non-fluffy nonwoven fabric layer 230) containing no heat-expandable particles on the second surface side of the nonwoven fabric sheet. Weaving fiber The heat-expandable particles 260 in the bulky nonwoven fabric layer 205 on the first surface side of the sheet are peeled off from the second surface side of the nonwoven fabric sheet, and the fluffy nonwoven fabric 200 can be imparted with a certain flexibility. Further, the surface layer portion 210 on the first surface side of the nonwoven fabric sheet is such that the melt 240 of the heat-expandable particles is at least partially filled between the fibers 250 to bond the fibers 250 to each other, and the melt 240 of the heat-expandable particles The function of reinforcing the film, that is, preventing the heat-expandable particles 260 of the inner portion 220 of the bulky nonwoven fabric layer 205 (that is, between the surface layer portion 210 on the first surface side and the non-fluffy nonwoven fabric layer 230) from being formed from the foregoing The first surface side of the nonwoven fabric sheet is detached to the outside, and the surface strength of the nonwoven fabric sheet is increased. Therefore, the heat-expandable particles 260 inside the bulk nonwoven fabric 200 are less likely to fall off, and the stretch of the bulk nonwoven fabric 200 can be improved. Strength (especially tensile strength at wet) and surface strength (friction fastness) of the first surface described above. Further, in the heat treatment step, since only one surface (first surface) of the laminated strip body is heated, heat is not easily transmitted to the inside 220 of the bulky nonwoven fabric layer 205, and the first surface can be located. The thermally expandable particles of the surface layer portion 210 are more efficiently and more reliably melted.

Further, in each of the above embodiments, the step A is a step of continuously producing a nonwoven fabric sheet containing expanded heat-expandable particles from the tape raw material. However, the present invention is not limited to such a form, and for example, it is prepared to contain expansion. The step A of the non-woven fiber sheet of the heat-expandable particles may be a step of preparing a nonwoven fabric sheet or a commercially available nonwoven fiber sheet produced by another step or the like. Further, the present invention is not limited to the above embodiments, and may be adapted to the scope and spirit of the present invention. When combining or changing, etc.

The fluffy non-woven fabric produced by the method of the present invention is excellent in the ability to capture dirt due to fluffiness, and it is difficult to cause the heat-expandable particles to fall off even when vibration or the like is imparted. Therefore, it can be excellent even when applied to paper towels and the like for a long period of time. Wiping sex. Further, the fluffy non-woven fabric of the present invention has a lot of space for accumulating water in the non-woven fabric due to fluffiness, and has a soft and comfortable skin feel by containing a large amount of expanded heat-expandable particles in the interior, in addition to high water retention capacity. Therefore, it can be applied to a tissue paper which is required to be soft as a buttock. Further, in the fluffy nonwoven fabric of the present invention, the melt of the heat-expandable particles located in the surface layer portion functions as a reinforcing film for improving the surface strength, and the surface strength, particularly the tensile strength and the rubbing fastness at the time of wetting, are high. It is also excellent in stability, and therefore, when applied to an absorbent body of an absorbent article such as a sanitary pad, it can realize an absorbent body that is not easily collapsed and is not easily deformed.

[Examples]

Hereinafter, the present invention will be specifically described by way of examples and comparative examples, but the present invention is not limited to the examples.

[Example 1]

In the nonwoven fabric manufacturing apparatus 1 used in the method for producing a fluffy nonwoven fabric according to the first embodiment of the present invention, the fluffy nonwoven fabric of the first embodiment is produced in accordance with the respective steps of the first embodiment. First, a tape raw material containing the following components: 48% by mass of conifer bleached hide paper pulp (NBKP), 嫘萦 fiber having a fineness of 0.7 dtex and a fiber length of 4 mm (manufactured by Daiwabo Rayon Co., Ltd., CORONA); a heat-expandable particle having a melting point of 5 to 15 μm and an expansion starting temperature of 75 ° C and a thermoplastic resin having a shell portion of 190 ° C (Matsumoto microsphere F-36, manufactured by Matsumoto Oil & Fats Co., Ltd.) having a fineness; Heat-fusible fiber (manufactured by Teijin Co., Ltd., TJ04CN) of 1.1 dtex, fiber length 5 mm PET/low melting point PET (melting point 110 ° C); thermal expansion property of cationically modified acrylic copolymer A particle-fixing agent (manufactured by Asahi Kasei Co., Ltd., Filex RC-104) was 3.0% by mass; and a heat-expandable particle-fixing agent (manufactured by Meisei Chemical Co., Ltd., Filex M) of an anionic acrylic copolymer was 3.0% by mass. As shown in Fig. 1, the raw material supply head was used to supply the raw material to the conveyance belt of the first conveyance belt to form an initial belt having a basis weight of 40 g/m ² . Then, as shown in Fig. 1, the initial tape is transferred onto a conveyance belt of the second conveyance belt, conveyed, dehydrated in the pressurized dewatering section, and transferred to a Yankee dryer heated to 105 °C ( Drying roller), the strip after drying is dried until the moisture content reaches 60%.

Next, using a steam nozzle (nozzle aperture 200 μm, 6 rows in the MD direction, hole pitch 1 mm), water vapor of about 140 ° C was sprayed to the second surface of the dried belt (mixed sheet) at a vapor pressure of 0.4 MPa. The heat-expandable particles dispersed in the body after drying are expanded by the high-temperature treatment. The distance between the aforementioned steam nozzle and the dried belt body was 2.0 mm. Further, on the first surface side of the belt after drying, the suction drum is disposed at a position facing the steam nozzle, and the outer circumference is provided with stainless steel. The steel 18-piece perforated sleeve has a suction attraction of -5.0 kPa.

Then, the strip after the high-temperature treatment is transferred to the first surface-side heat treatment heat roller heated to 200° C., and the heat-expandable particles in the surface layer portion on the first surface side of the strip are melted and in-band. The constituent fibers are welded. Furthermore, the belt body after the first surface side heat treatment is transferred to a second surface side heat treatment heat roller heated to 200° C., and the heat-expandable particles in the surface layer portion on the second surface side of the belt body are melted. It is welded to the constituent fibers in the belt body. The respective water contents of the strip after the heat treatment on the first surface side and the strip after the heat treatment on the second surface side are each 5% or less and 3% or less. Then, the belt body after the heat treatment on the second surface side was wound around a winding roll, whereby the bulk nonwoven fabric of Example 1 was obtained. Further, the basis weight and the water content of the above tape are measured in accordance with the measurement method described later.

[Example 2]

In the nonwoven fabric manufacturing apparatus 1' used in the method for producing a fluffy nonwoven fabric according to the second embodiment of the present invention, the fluffy nonwoven fabric of the second embodiment is produced in the order of the second embodiment. First, a first tape raw material containing the following components: 50% by mass of conifer bleached hide pulp (NBKP); and 嫘萦 fiber having a fineness of 0.7 dtex and a fiber length of 7 mm (made by Daiwabo Rayon Co., Ltd., CORONA) 50 were prepared. quality%. Then, as shown in FIG. 3, the first tape raw material supply head is supplied to the conveyance belt (OS-80 manufactured by NIPPONFILCON Co., Ltd.) of the first conveyance conveyor using the first tape raw material supply head to form a basis weight of 20 g. The first tape of /m ² . Then, a high-pressure water jet is sprayed onto the first belt body using a high-pressure water jet nozzle, and the first belt body is subjected to high-pressure water flow treatment. The process conditions of high-pressure water, using the system: high pressure water stream energy ^{0.28460kW / m 2 (0.14230kW / m} 2 Embodiment 2), the processing speed of 70m / min, the first between the front and high pressure water nozzle strip The distance was 10 mm, and the high-pressure water jet nozzle used was a nozzle hole having a hole diameter of 92 μm arranged at a pitch of 0.5 mm. Further, the high-pressure water flow energy described above can be calculated by the following formula.

Energy (kW/m ² ) = 1.63 × injection pressure (kg/cm ² ) × injection flow rate (m ³ /min) / treatment speed (m / min) / 60

Here, the injection flow rate (m ³ /min) = 750 × total opening area of the orifice (m ² ) × injection pressure (kg/cm ² ) ^0.495 .

Then, the first tape body after the high-pressure water flow treatment is transferred to the conveyance belt of the second conveyance conveyor, and the second tape raw material containing the following components is prepared: 48% by mass of conifer bleached hide pulp (NBKP); A fiber having a fineness of 0.7 dtex and a fiber length of 4 mm (manufactured by Daiwabo Rayon Co., Ltd., CORONA) of 18% by mass; a particle diameter of 5 to 15 μm, an expansion starting temperature of 75 ° C, and a thermoplastic resin forming a shell portion; a heat-expandable particle having a melting point of 190 ° C (manufactured by Matsumoto Oil & Fats Co., Ltd., Matsumoto microsphere F-36) 10% by mass; a core sheath having a fineness of 1.1 dtex and a fiber length of 5 mm PET/low melting point PET (melting point 110 ° C) Heat-fusible fiber (manufactured by Teijin Co., Ltd., TJ04CN) having a structure of 18% by mass; a thermally expandable particle fixing agent of a cationically modified acrylic copolymer (manufactured by Mingcheng Chemical Industry Co., Ltd., FilexRC-104); 3.0% by mass; The heat-expandable particle fixing agent (FilexM, manufactured by Meisei Chemical Industry Co., Ltd.) of the acrylic copolymer was 3.0% by mass. The second tape raw material was supplied into a papermaking tank, and was sucked by a rotating circular net to form a second tape having a basis weight of 20 g/m ² on a circular net. Then, the second belt volume layer formed on the circular net is transferred onto the first belt body on the conveyance belt of the second conveyance belt to form a laminated belt body.

Then, as shown in FIG. 3, the laminated tape body is dehydrated in the pressurized dewatering section, and then transferred to a first Yankee dryer (first drying roll) heated to 105 ° C to dehydrate the moisture content to 60. The layered strip after % is dried. Next, using a steam nozzle (nozzle aperture 200 μm, 6 rows in the MD direction, hole pitch 1 mm), water vapor of about 140 ° C was sprayed to the first surface of the dried laminated belt body at a vapor pressure of 0.4 MPa (second belt) The side of the body)). By the high-temperature treatment, the thermally expandable particles dispersed in the fiber layer of the second belt body from the laminated belt body are expanded. The distance between the aforementioned steam nozzle and the dried belt body was 2.0 mm. Further, the suction drum disposed at a position facing the steam nozzle and its suction force are the same as in the first embodiment.

Then, the laminated tape body after the high-temperature treatment was transferred to a second Yankee dryer (second drying roll) heated to 160 ° C, and dried to a moisture content of 5% or less. Furthermore, the laminated strip which has been dried by the second Yankee dryer is transferred to the first surface side heat treatment heat roller heated to 200 ° C and heated to have the first surface of the laminated strip body present. The thermally expandable particles in the surface layer portion of the side (the second belt side) are melted and welded to the constituent fibers in the belt body. The water content of the laminated tape body after the first surface side heat treatment is 3% or less. Further, the laminated tape body after the heat treatment on the first surface side was wound around a winding roll, whereby the bulk nonwoven fabric of Example 2 was obtained. In addition, The basis weight and water content of the above tape are measured in accordance with the measurement method described later.

[Example 3]

The fluffy nonwoven fabric of Example 3 was obtained in the same manner as in Example 1 except that the first surface side of the surface heat treatment portion and the second surface side heat treatment heat roller were made of a hot embossing roll.

[Comparative Example 1]

The fluffy nonwoven fabric of Comparative Example 1 was obtained in the same manner as in Example 1 except that the heat treatment by the heat treatment rolls for the first surface side and the second surface side heat treatment of the surface heat treatment portion was not performed.

The fluffy nonwoven fabrics of Examples 1 to 3 and Comparative Example 1 were measured by the following measurement methods: moisture content after drying by each drying roll and heat treatment by each heat treatment heat roller, initial band, and The basis weight of the belt body and the second belt body, and the thickness, density, tensile strength during drying, tensile strength at the time of wetting, moisture absorption amount, rubbing fastness, and peeling of the heat-expandable particles. The thickness, density, tensile strength at the time of drying, tensile strength at the time of wetting, moisture absorption, rubbing fastness, and the presence or absence of heat-expandable particles were measured as shown in Table 1. Further, with respect to the fluffy nonwoven fabrics of Example 1 and Comparative Example 1, the cross section of the fluffy nonwoven fabric and the surface of the first surface were taken by an electron microscope photograph. The photographed electron microscope photographs are shown in Figs. 5 and 6.

<moisture rate>

A test piece of 30 cm × 30 cm size was sampled, and the weight (W ₁ ) of the test piece was measured. The test piece after measuring the weight was allowed to stand in a constant temperature bath at 105 ° C for 1 hour to dry, and then the weight (D ₁ ) was measured. The water content was calculated according to the following formula. Further, the moisture content was an average value of 10 test pieces.

Moisture rate = (W _{1 -} D ₁ ) / W ₁ × 100 (%)

<basis weight>

In the initial tape system, the tapes for measurement of the first tape and the second tape were respectively produced by a nonwoven fabric manufacturing apparatus. Then, a measurement sample having a size of 30 cm × 30 cm was sampled from each of the strips, and the basis weight (g/m ² ) of each strip was calculated by measuring the weight of the sample for measurement. Further, the basis weight is an average value of 10 measurement samples.

<thickness>

A measurement sample of 10 cm × 10 cm in size was sampled from the manufactured fluffy nonwoven fabric. 15cm measured using a thickness gauge includes a member of the ² ((shares) Daiei Chemical Seiki Seisakusho Type FS-60DS), to 3gf / cm ² load measurement conditions, the measurement of sample thickness. The thickness of three parts was measured for one sample for measurement, and the average value of the thickness of the three parts was made into the thickness (mm) of a fluffy nonwoven fabric.

<density>

A measurement sample of 10 cm × 10 cm in size was sampled from the manufactured fluffy nonwoven fabric. The weight of the sample for measurement was measured, and the density (g/cm ³ ) of the bulky nonwoven fabric was calculated from the weight and the above thickness.

<tensile strength upon drying>

A rectangular test piece having a width of 25 mm in the longitudinal direction and a rectangular test piece having a width of 25 mm in the same direction as the CD direction was cut out from the manufactured fluffy non-woven fabric, and a sample for measurement was prepared. For the sample for measurement in the MD direction and the CD direction, a tensile tester (manufactured by Shimadzu Corporation, Autogaraph type AGS-1kNG) with a maximum load capacity of 50 N was used, and the distance between the clamps of 100 mm was 100 mm. / Tensile speed conditions, tensile strength was measured. The measurement system was performed three times using three measurement samples, and the average value of the three measurement values was taken as the dry tensile strength (N/25 mm) in the MD direction and the CD direction, respectively.

<wet tensile strength>

Cut from the manufactured fluffy non-woven fabric: a long strip test piece of 25 mm width in the longitudinal direction and the MD direction, and a long strip test piece of 25 mm width in the longitudinal direction and the CD direction, and a sample for measurement was prepared. Distilled water of 2.5 times the mass of the prepared measurement sample was impregnated into the measurement sample (water content ratio: 250%). For the sample for measurement in the MD direction and the CD direction, a tensile tester (manufactured by Shimadzu Corporation, Autogaraph type AGS-1kNG) with a maximum load capacity of 50 N was used, and the distance between the clamps of 100 mm was 100 mm. / Tensile speed conditions, tensile strength was measured. The measurement system uses three measurement samples respectively. Three times, the average value of the three measured values was taken as the wet tensile strength (N/25 mm) in the MD direction and the CD direction, respectively.

<water absorption amount>

A measurement sample of 10 cm × 10 cm in size was sampled from the manufactured fluffy nonwoven fabric. After measuring the mass of the measurement sample, the measurement sample was immersed in distilled water for 1 minute. Next, after standing on a net (80 mesh) for 1 minute, the mass of the measurement sample was measured. The value of the mass of the measurement sample immersed in the distilled water is subtracted from the mass of the measurement sample immersed in the distilled water, and converted into a value of 毎1 m ² non-woven fabric, and the converted value is taken as the moisture absorption amount (g/m ² ). .

<Friction fastness>

A sample for measurement of a width of 300 mm × a length of 200 mm was produced from a manufactured fluffy nonwoven fabric, and a sample for measurement was mounted on the surface to be measured in a dye-resistant rubbing fastness tester (manufactured by Daiei Scientific Seiki Co., Ltd.). At this time, a cloth tape was attached to the surface of the mounting surface of the testing machine that was in contact with the sample for measurement, and the measurement sample was placed so that the moving direction of the sliding sheet coincided with the longitudinal direction of 200 mm of the measurement sample. Then, the friction coefficient was measured at a friction round trip speed of 30 times/min and a load of 200 g until the surface of the measurement sample was damaged. The number of times of measurement of the friction coefficient until the surface of the sample for measurement was damaged was taken as the rubbing fastness (times).

<Thermal expansion particle shedding test>

A sample for measurement having a width of 150 mm and a length of 150 mm was sampled from the production of a fluffy nonwoven fabric. The sample for measurement was sandwiched with a black paper of A4 size, and shaken at 300 rpm for 10 minutes using a vertical oscillating machine (IWAKI Co., Ltd., SHKV-200), and then it was visually confirmed whether or not the thermally expandable particles were peeled off on the black paper.

As shown in Table 1, the fluffy nonwoven fabric of Comparative Example 1 which was not subjected to the surface heat treatment was confirmed to have the peeling of the heat-expandable particles, but the fluffy nonwoven fabrics of Examples 1 to 3 did not show the peeling of the heat-expandable particles. Further, the fluffy nonwoven fabrics of Examples 1 to 3 were superior to the fluffy nonwoven fabric of Comparative Example 1 in tensile strength, tensile strength at the time of wetness, and abrasion fastness during drying.

And, according to the electron microscope shown in Figures 5 (a) and (b) In the photograph, it was found that the fluffy nonwoven fabric of Example 1 was in the surface layer portion, and the heat-expandable particles were melted and welded to the constituent fibers to cover most of the surface of the fluffy nonwoven fabric. Furthermore, it was found that the fluffy nonwoven fabric of Example 1 was in the inside of the surface layer portion, and the heat-expandable particles maintained the form of expanded particles.

On the other hand, according to the electron micrographs shown in Figs. 6(a) and 6(b), it is found that the fluffy nonwoven fabric of Comparative Example 1 which is not subjected to the surface heat treatment has a large number of thermally expandable particles present on the surface and the surface layer portion of the fluffy nonwoven fabric. It is in a state of being easily detached by vibration or the like at the time of use.

Claims (9)

A method for producing a fluffy nonwoven fabric, comprising: Step A, preparing a non-woven fabric sheet having a first surface and a second surface opposite to the first surface, the nonwoven fabric sheet comprising a fluffy nonwoven fiber layer, the fluffy The woven fiber layer contains the expanded heat-expandable particles and the fibers to form the first surface; and in the step B, at least the first surface of the nonwoven fabric sheet is heated by a heat roll or a hot embossing roll to make the nonwoven fabric The heat-expandable particles of the surface layer portion of the fiber sheet at least on the first surface side are melted, and the heat-expandable particles located inside the nonwoven fabric sheet, that is, inside the surface layer portion, are not melted, and the expanded portion is maintained. Particle-like form. The manufacturing method of claim 1, wherein the step A includes the step of forming the fluffy nonwoven fabric layer by contacting the moist hot air or water vapor above the expansion start temperature of the heat-expandable particles to the unexpanded The heat-expandable particles and the mixed sheet formed by mixing the fibers expand the unexpanded heat-expandable particles to form the bulky nonwoven fabric layer. The manufacturing method of claim 1 or 2, wherein the heat-expandable particles include a shell portion made of a thermoplastic resin and a swelling agent contained in the shell portion, and the step B includes a melting point of the thermoplastic resin or more The nonwoven fabric sheet is heated at a temperature lower than a temperature of 10 ° C higher than the melting point of the thermoplastic resin. The manufacturing method of claim 1 or 2, wherein the nonwoven fabric sheet before heating the nonwoven fabric sheet has a water content of 5% by mass or less. The manufacturing method of claim 1 or 2, wherein the aforementioned fluffy non-woven The fiber layer constitutes the second surface opposite to the first surface, and the step B includes heating the first surface and the second surface of the nonwoven fabric sheet so as to be located on the first surface side of the nonwoven fabric sheet and The heat-expandable particles in the surface layer portions on the second surface side are melted. The manufacturing method of claim 1 or 2, wherein the nonwoven fabric sheet further comprises a nonwoven fabric layer constituting the second surface and not containing heat-expandable particles, and the step B includes: only the nonwoven fabric sheet The one surface is heated to melt the heat-expandable particles located in the surface layer portion on the first surface side of the nonwoven fabric sheet. A fluffy nonwoven fabric having a first surface and a second surface opposite to the first surface, wherein the fluffy nonwoven fabric contains a bulky nonwoven fabric layer, and the fluffy nonwoven fabric layer contains expanded heat-expandable particles and fibers to form the first The surface layer portion of at least the first surface side of the fluffy nonwoven fabric contains a melt of the heat-expandable particles which are at least partially filled between fibers and which bonds the fibers to each other, and the inside of the nonwoven fabric sheet That is, the heat-expandable particles are not melted to the inside of the surface layer portion, and the expanded particulate form is maintained. The fluffy nonwoven fabric of claim 7, wherein the fluffy nonwoven fabric layer constitutes the second surface opposite to the first surface, and each of the surface layers on the first surface side and the second surface side of the fluffless nonwoven fabric contains at least A melt of the heat-expandable particles that partially fills the fibers and bonds the fibers to each other. Such as the fluffy non-woven fabric of claim 7, wherein the aforementioned fluffy non-woven fabric Further, the nonwoven fabric layer that constitutes the second surface and does not contain the heat-expandable particles, and the surface layer portion on the first surface side of the bulky nonwoven fabric contains the heat-expandable particles that are at least partially filled between the fibers to bond the fibers to each other. The melt.