JP5685889B2 - Hygroscopic cushion material - Google Patents

Description

  The present invention relates to a cushioning material having high hygroscopicity. Specifically, the present invention relates to a material in which hygroscopic particles are fixed to a highly breathable cushion base material.

  Conventionally, urethane foam, padding made of polyester fiber, resin cotton bonded with polyester fiber, solid cotton, or the like has been used as a cushioning material for bedclothes such as beds and seats for automobiles and trains. The comfort of sitting is influenced by the air permeability of the cushioning material as well as the cushioning when sitting, but urethane foam, padding made of polyester fiber, resin cotton bonded with polyester fiber, or solid cotton In conventional cushion materials such as the above, there is a limit to improving air permeability. In addition, although the foam-crosslinked urethane has good durability as a cushioning material, there is a problem that it is inferior in moisture permeability and water permeability and easily heats up because of heat storage.

  As a technique for reducing the feeling of unevenness of the cushion material, for example, a material (see Patent Document 1 (Example 2)) in which a binder resin and hygroscopic fine particles are sandwiched between polyester nonwoven fabrics has been proposed. However, in this method, the hygroscopic fine particles are buried in the resin, and the original hygroscopic performance is lost. In addition, since the binder resin is non-porous, there is a problem that the air permeability and moisture permeability of the material are lowered. Moreover, since a binder resin is pinched | interposed and it is made to adhere with a nonwoven fabric by heating, a raw material will become hard and it will be inferior to cushioning properties.

  Patent Document 2 proposes an unevenly-absorbent water-absorbent fabric having the ability to easily transfer moisture from one surface of the fabric to the other surface. However, this unevenly-distributed water-absorbent fabric only transfers moisture from one surface to the other surface and is not sufficiently hygroscopic. Further, in order to facilitate the transfer of moisture, it is necessary to reduce the thickness of the fabric, and cushioning properties cannot be obtained.

  In Patent Document 3, in a three-dimensional structure knitted fabric composed of yarns that join the knitted fabric on the front and back surfaces and both the front and back surfaces composed of a fiber structure, the inside of the fibers constituting the three-dimensional structured knitted fabric There has been proposed a method for reducing moisture sensation by adding a hygroscopic agent such as polyalkylene glycol or imparting hygroscopicity by graft polymerization of a hydrophilic vinyl monomer or the like (Patent Document 3 (paragraph [ [0073])). However, in this method, since a hygroscopic agent is kneaded into the fiber raw material or the fiber itself is modified, it is considered that the spinnability is deteriorated, and there is a problem in workability and product handling.

  Patent Document 4 proposes an adsorbent-carrying fiber structure material in which an adsorbent is bonded to the inside of a cavity with a binder for a fiber structure material having a through-hole and a predetermined volume filling degree. However, with this material, the moisture permeability of the fiber structure material is sufficient, but porous inorganic particles are used as the adsorbent, and moisture is adsorbed into the pores of the inorganic particles. Since it takes a long time, the moisture absorption rate is slow, and the sensation of feeling when used for a short time cannot be sufficiently reduced. Further, since the binder used is impermeable to moisture, the portion of the inorganic particles that is in contact with the binder cannot exhibit the adsorption ability, and the original moisture absorption performance is lost.

JP 2004-155396 A JP-A-56-134263 JP 2001-98445 A JP-A-4-41753

Conventionally, various cushioning materials with reduced sensation have been proposed, but none of them have all of excellent moisture absorption speed, high air permeability and high cushioning properties.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a moisture-permeable and cushioning material excellent in moisture absorption speed, air permeability and cushioning properties.

The moisture permeable cushioning material of the present invention that has solved the above-described problems has a cushion base material made of fibers and hygroscopic fine particles fixed to the fiber surface constituting the cushion base material made of the fibers. The moisture-permeable cushion material is characterized in that the moisture-absorbent cushion material itself has a moisture absorption rate per unit volume of 50 g / m ³ · min or more and an air permeability of 100 cm ³ / cm ² · s or more.

  The cushion base material made of the fibers is preferably a double knitted fabric made of two ground structures on the front and back sides and a connecting yarn that connects the two ground structures. The hygroscopic fine particles are preferably fixed to the fiber surface with a cured porous binder resin. The hygroscopic fine particles preferably contain 1.0 mmol / g or more of a salt-type carboxyl group, and the volume average particle diameter of the hygroscopic fine particles is preferably 50 μm or less.

  The moisture-permeable cushion material of the invention has high air permeability and has a very high moisture absorption rate due to the action of the hygroscopic fine particles. Therefore, it is excellent in air permeability, hygroscopicity, and cushioning properties, and it is possible to quickly reduce the sensation of feeling when used for a short time.

The hygroscopic cushion material of the present invention is a hygroscopic cushion material having a cushion base material composed of fibers and hygroscopic fine particles fixed to the surface of the fibers constituting the cushion base material composed of fibers. The wet cushioning material itself has a moisture absorption rate per unit volume of 50 g / m ³ · min or more and an air permeability of 100 cm ³ / cm ² · s or more.

  In the hygroscopic cushion material of the present invention, hygroscopic fine particles are given to the fiber surface of the cushion base material, and the cushion material itself has high air permeability. Therefore, since moisture easily penetrates into the cushion material, for example, moisture generated between the cushion material and human skin quickly penetrates into the cushion material. And the water | moisture content which osmose | permeated the inside of a cushion material will be adsorb | sucked rapidly by a hygroscopic fine particle. That is, the cushioning material of the present invention has a very high moisture absorption rate due to the high air permeability and the action of the hygroscopic fine particles. Therefore, it is possible to quickly reduce the sensation of feeling when used for a short time.

The moisture absorption rate per unit volume of the hygroscopic cushion material is 50 g / m ³ · min or more. If the moisture absorption rate is less than 50 g / m ³ · min, the moisture absorption rate is too slow, so that the feeling of swaying during short-time use cannot be sufficiently reduced. In addition, from the viewpoint of further reducing the feeling of unevenness when used for a short time, the moisture absorption rate is preferably 55 g / m ³ · min or more, more preferably 60 g / m ³ · min or more. In addition, although the upper limit of a moisture absorption rate is not specifically limited, Usually, it is 100 g / m < ³ > * min. A method for measuring the moisture absorption rate will be described later.

The moisture permeability of the moisture-permeable cushion material is 100 cm ³ / cm ² · s or more. If the air permeability is less than 100 cm ³ / cm ² · s, moisture hardly penetrates into the cushion material, and the hygroscopicity of the hygroscopic fine particles is hindered, and there is a possibility that the effect of reducing the sensation of sensation may not be exhibited. In addition, when the air permeability is less than 100 m ³ / cm ² · s, moisture absorbed by the hygroscopic fine particles becomes difficult to be released, and the hygroscopic performance of the hygroscopic fine particles is easily saturated, and the hygroscopic property of the hygroscopic cushion material Inferior in sustainability. From such a viewpoint, the air permeability is preferably 200 cm ³ / cm ² · s or more. The upper limit of the air permeability is not particularly limited, but is usually 500 cm ³ / cm ² · s. The air permeability is determined by an air permeability test measured according to JIS L1096 (8.26.1 A method).

  The thickness of the moisture-permeable cushion material of the present invention is preferably 1 mm or more, more preferably 2 mm or more, and further preferably 3 mm or more. If thickness is 1 mm or more, cushioning property will become more favorable. If the moisture-permeable cushion material is too thick, the hygroscopic property of the internal moisture-absorbing fine particles becomes difficult to be exhibited. Therefore, the upper limit of the thickness of the moisture-permeable cushion material is usually 20 mm.

The basis weight of the moisture-permeable cushion material of the present invention is preferably 300 g / m ² or more, more preferably 330 g / m ² or more, still more preferably 350 g / m ² or more, and preferably 550 g / m ² or less, more preferably It is 500 g / m ² or less, more preferably 450 g / m ² or less. When the basis weight is 300 g / m ² or more, the cushioning property is better, and when the basis weight is 550 g / m ² or less, the air permeability of the moisture-absorbent and moisture-absorbing cushion material is increased, and the effect of reducing the feeling of peeling is further improved.

Hereinafter, each member which comprises the moisture-permeable cushion material of this invention is demonstrated in detail.
<Cushion base material>

  The cushion base material is made of fiber. The fibers constituting the cushion base material composed of fibers are not particularly limited, natural fibers such as cotton, hemp, silk, wool, etc .; cellulose fibers such as rayon and acetate; polyamide resins such as polyamide 6, polyamide 66, and polyamide 12; Polytrimethylene terephthalate, polyethylene terephthalate, polybutylene terephthalate, polyester resins such as polylactic acid, polyolefin resins such as polyethylene and polypropylene, synthetic resins such as polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, and polyacrylonitrile, and their co-polymers Synthetic fibers formed from a resin comprising a coalesced or blended body. The synthetic resin fiber may contain additives such as a matting agent, a flame retardant, an antistatic agent, and a pigment, and may be compounded in a core-sheath and side-by-side form. These fibers may be used alone or in combination of two or more. Among these, it is preferable to use a synthetic fiber formed from a polyester resin or a polyamide resin from the viewpoint of versatility.

  The cross-sectional shape of the fibers constituting the cushion base material made of fibers is not particularly limited, and any shape can be used. Particularly in the case of synthetic fibers, the cross-sectional shape can be freely designed. Specifically, the cross-sectional shape of the fiber is round: flat; triangular, L-shaped, T-shaped, Y-shaped, W-shaped, dog-bone shaped, etc .; trilobal, eight Examples include multi-leaf type such as leaf type; hollow type; The form of the fiber may be any of raw yarn, spun yarn, twisted yarn, false twisted yarn, fluid jet yarn, etc., and may be a multifilament yarn or a monofilament yarn. Moreover, you may mix these 2 or more types of fibers from which these raw materials, cross-sectional shapes, and forms differ by well-known composite means, such as a entanglement, a twist, a composite false twist process, a knit.

  As a cushion base material which consists of the said fiber, a solid knitted fabric, a nonwoven fabric, hard cotton, felt etc. are mentioned, for example. Among these, a three-dimensional knitted fabric is preferable, and a double knitted fabric composed of two ground structures on the front and back sides and a connecting yarn that connects the two ground structures, a so-called double raschel fabric, is particularly preferable.

Hereinafter, a double knitted fabric (hereinafter sometimes simply referred to as “double knitted fabric”) composed of two ground structures on the front and back sides and connecting yarns connecting the two ground structures will be described in detail. .
The knitted fabric on the surface constituting the double knitted fabric (the side that comes into contact with the human body when used for bedding, seat cushions, etc.) is superior in hygroscopicity and water absorption to improve the comfort of touch. Is preferred. Therefore, the fibers constituting the surface knitted fabric include natural fibers such as cotton, hemp, silk, and wool; cellulose fibers such as rayon and acetate; synthetic fibers having an irregular cross section such as a W shape; hygroscopicity and water absorption Synthetic fibers with modified properties; etc. are preferred. The knitted fabric on the back surface (opposite side of the front surface) is not particularly limited, and any of the fibers exemplified as the fibers constituting the cushion base material can be suitably used for the fibers constituting the back knitted fabric.

  The thickness of the fibers constituting the front and back knitted fabrics is preferably 50 dtex or more, more preferably 100 dtex or more, and 300 dtex or less for both monofilament yarns and multifilament yarns (total fineness in the case of multifilaments). Is more preferable, and 200 dtex or less is more preferable. In the case of multifilament yarn, the single yarn fineness is preferably 0.1 dtex or more, more preferably 0.5 dtex or more, preferably 7 dtex or less, more preferably 6 dtex or less, and further preferably 3 dtex or less.

  The knitting structure of the front and back knitted fabrics is not particularly limited. For example, a flat structure (for example, tricot knitting, cord knitting, atlas knitting which is a three-dimensional structure of warp knitting); mesh knitting such as square or hexagon; Etc. The combination of the knitting structures of the front and back knitted fabrics may be the same or different. As a combination of the front and back knitted structures, for example, the surface knitted fabric has a flat structure to improve the touch, and the back knitted fabric has a plurality of openings such as square, hexagonal mesh knitted fabric, marquisette knitted fabric, etc. A combination that improves the air permeability by using a knitted fabric; a combination that improves the air permeability by improving the air permeability by forming a knitted fabric having a plurality of openings on both the front and back sides, etc. is preferable.

  When the knitted structure is a mesh knitted fabric, the maximum mesh diameter in the course direction of the mesh knitted fabric is preferably 1 mm or more (more preferably 1.5 mm or more), and preferably 6 mm or less (more preferably 5 mm or less). If the maximum diameter of the mesh is 1 mm or more, the air permeability is good and the anti-swelling performance is further improved, and if it is 6 mm or less, fraying of the stitched portion on the outer periphery of the three-dimensional knitted fabric can be further suppressed. In the mesh knitted fabric, the knitted fabric width in the course direction between the meshes constituting the mesh is preferably 0.8 mm or more (more preferably 1 mm or more), and preferably 5 mm or less (more preferably 4 mm or less). If the knitted fabric width is 0.8 mm or more, the three-dimensional knitted fabric is less likely to be crushed, and the anti-raising property is further improved.

  As the connecting yarn for connecting the front and back knitted fabrics, the fibers exemplified as the fibers constituting the cushion base material can be used. Among these, since the cushioning property with a feeling of elasticity can be imparted and the durability of the cushioning property after repeated or long-time compression becomes good, polytrimethylene terephthalate fiber is used for at least a part of the connecting yarn. It is preferable. Moreover, about the cross-sectional shape of a fiber, since durability of cushioning property becomes favorable, a round-shaped cross section is preferable.

  The connecting yarn is preferably a monofilament yarn from the viewpoint of reducing the displacement force. The connecting yarn is preferably 100% by mass of monofilament yarn, but multifilament yarn or false twisted yarn may be mixed. In this case, the amount of monofilament yarn used is preferably 30% by mass or more, and more preferably 50% by mass or more. In the case of monofilament yarn, the fineness of the connecting yarn is preferably 10 dtex or more (more preferably 30 dtex or more), and preferably 500 dtex or less (more preferably 300 dtex or less). In the case of multifilament yarn, the total fineness of the connecting yarn is preferably 20 dtex or more (more preferably 30 dtex or more), preferably 300 dtex or less (more preferably 200 dtex or less), and the single yarn fineness is 1 dtex or more (more preferably 2 dtex or more). Preferably, it is 7 dtex or less (more preferably 6 dtex or less).

  The connection structure of the knitted fabric of the front and back by the said connection thread is not specifically limited, For example, a straight structure, a strut structure, a cross structure, a truss structure, etc. are mentioned.

  The double knitted fabric can be knitted by a knitting machine having two rows of needle beds facing each other, and can be knitted by a double raschel knitting machine, a flat knitting machine having a V bed, or the like. Among these, it is preferable to use a double raschel knitting machine in order to obtain a three-dimensional knitted fabric with good dimensional stability. The gauge of the knitting machine is preferably 9 to 28 gauge.

  In addition, a double knitted fabric may be manufactured as mentioned above, and may select and use what has the physical property prescribed | regulated by this invention from what is marketed. Specific examples of commercially available double russell fabrics include Asahi Kasei Fibers Fusion (registered trademark), Unitika Technos Cubic Eye (registered trademark), and the like.

The air permeability of the cushion base material is preferably 150 cm ³ / cm ² · s or more, more preferably 200 cm ³ / cm ² · s or more, and preferably 500 cm ³ / cm ² · s or less. If the air permeability of the cushion base material is within the above range, it becomes easy to control the air permeability of the obtained moisture-permeable cushion material to a suitable range.

Moisture permeability is preferably at least 8000g / m ² · 24h of the cushion base, more preferably 10000g / m ² · 24h or more, still more preferably 12000g / m ² · 24h or more. If the moisture permeability is 8000 g / m ² · 24 h or more, moisture easily penetrates into the cushion base material, the hygroscopicity of the hygroscopic fine particles is promoted, and the effect of reducing the feeling of detachment is further improved. The upper limit of moisture permeability is not particularly limited, but is usually 20000 g / m ² · 24 h. The moisture permeability is measured according to JIS L1099 (A-1 method).

  The thickness of the cushion base material is preferably 1 mm or more, more preferably 2 mm or more, and further preferably 3 mm or more. If the thickness of the cushion base material is 1 mm or more, the cushioning property becomes better. In addition, since it will become difficult to exhibit the hygroscopic property of an internal hygroscopic fine particle when a cushion base material becomes too thick, the upper limit of the thickness of a cushion base material is 20 mm normally.

The basis weight of the cushion base is 200 g / m ² or more, more preferably 250 g / m ² or more, more preferably 300 g / m ² or more, preferably 450 g / m ² or less, more preferably 400 g / m ² Hereinafter, it is more preferably 350 g / m ² or less. When the basis weight is 200 g / m ² or more, the cushioning property is further improved, and when it is 450 g / m ² or less, a decrease in air permeability and moisture permeability can be suppressed, and the anti-swelling performance is further improved.

<Hygroscopic fine particles>
The hygroscopic fine particles are not particularly limited as long as the object of the present invention can be achieved, but from the viewpoint of the hygroscopic rate, those that adsorb water molecules by a chemical adsorption action are preferable. If a material having a chemical adsorption action is used, the moisture absorption rate of the moisture permeable cushioning material can be improved, and the feeling of unevenness when used for a short time can be reduced. On the other hand, those that adsorb water molecules by physical adsorption action, such as materials with pores such as activated carbon, take a long time to adsorb water molecules. There is a risk that it cannot be sufficiently reduced.

  Examples of the hygroscopic particles having a chemical adsorption action include organic particles having a salt-type carboxyl group. Among these, organic particles having a salt-type carboxyl group are preferable. The adsorption action by the salt-type carboxyl group is a reversible action, and the moisture absorption performance can be restored again by drying after moisture absorption. Therefore, when such hygroscopic fine particles are used, the hygroscopic cushioning material can be repeatedly used by drying after moisture absorption.

Hereinafter, organic particles having a salt-type carboxyl group (hereinafter referred to as “hygroscopic fine particles”) will be described as an example of hygroscopic fine particles.
The hygroscopic fine particles preferably have a salt-type carboxyl group amount of 1.0 mmol / g or more, more preferably 3.0 mmol / g or more, and still more preferably 5.0 mmol / g or more. When the salt-type carboxyl group amount is 1.0 mmol / g or more, the moisture absorption rate of the moisture-permeable cushioning material is further improved.

  Examples of the hygroscopic fine particles include those obtained using an acrylic crosslinked polymer as a raw material. This “acrylic crosslinked polymer” refers to (meth) acrylic acid; (meth) acrylic acid alkyl esters such as methyl (meth) acrylate and ethyl (meth) acrylate; acrylics such as (meth) acrylic amide; Copolymerization of an acid monomer or a comonomer composition in which (meth) acrylonitrile or other acrylonitrile monomer having at least a polymerizable vinyl group and a nitrile group is added with another comonomer as necessary. It means the one obtained by introducing a crosslinked structure into the acrylic polymer. Here, “(meth) acrylic acid” refers to acrylic acid and / or methacrylic acid.

  The acrylic acid monomer or acrylonitrile monomer used for the acrylic polymer may be used alone or in combination of two or more. In addition, the other copolymerizable monomer is not particularly limited as long as it does not impair the action of the finally obtained moisture-absorbing and releasing fine particles. For example, vinyl halide, vinylidene halide, p-styrenesulfonic acid Sulfonic acid-containing monomers such as salts and salts thereof, vinyl compounds such as styrene and vinyl acetate, vinylidene compounds, and the like can be used.

  For introducing the cross-linked structure, a method of adding a compound having two or more polymerizable vinyl groups as a copolymer component for forming a cross-linked structure to the above comonomer monomer composition and copolymerizing the compound can be employed. As the compound having two or more polymerizable vinyl groups, triallyl isocyanurate, triallyl cyanurate, divinylbenzene, ethylene glycol di (meth) acrylate, methylenebisacrylamide and the like are preferably used.

  Further, when the acrylic polymer is an acrylonitrile polymer obtained by copolymerizing a copolymer monomer composition in which another copolymer monomer is added to an acrylonitrile monomer as required, It is also possible to introduce a crosslinked structure by treatment with a hydrazine compound. Examples of hydrazine compounds that can be used in this case include hydrazine; hydrated hydrazine, sulfate hydrazine, hydrazine hydrochloride, hydrazine nitrate, hydrazine bromate, hydrazine carbonate, and the like; ethylenediamine, sulfate guanidine, guanidine hydrochloride, guanidine nitrate, phosphate And hydrazine derivatives such as guanidine and melamine. One of these other copolymerizable monomers, a compound having two or more polymerizable vinyl groups, and a hydrazine compound can be used alone or in combination of two or more.

  Each of the above acrylic cross-linked polymers has a carboxyl group or a functional group that can be modified to a carboxyl group, and the carboxyl group or a functional group that can be modified to a carboxyl group is chemically converted to a salt-type carboxyl group. Moisture absorption / release fine particles can be obtained by caulking.

  As such moisture-absorbing / releasing fine particles, for example, an acrylonitrile-based crosslinked polymer in which a crosslinked structure is introduced by a hydrazine-based compound into an acrylonitrile-based polymer obtained by copolymerizing a comonomer composition containing 50% by mass or more of acrylonitrile. Alternatively, the nitrile group of an acrylonitrile-based crosslinked polymer obtained by copolymerizing a comonomer composition containing 50% by mass or more of acrylonitrile and further containing a compound having two or more polymerizable vinyl groups, etc. is obtained by hydrolysis. Those which have been chemically converted into a type carboxyl group and contain 1.0 mmol / g or more of the salt type carboxyl group are preferred.

  As a more preferred embodiment, (A) an acrylonitrile polymer obtained by copolymerizing a comonomer composition containing 85% by mass or more of acrylonitrile has an increase in nitrogen content of 1.0 to 15.0% by mass. In the acrylonitrile-based crosslinked polymer having a crosslinked structure introduced by treatment with a hydrazine compound, the remaining nitrile group is chemically converted to a salt-type carboxyl group by hydrolysis, and the salt-type carboxyl group is converted to Hygroscopic fine particles having 1.0 mmol / g or more; (B) a comonomer composition containing 50% by mass or more of acrylonitrile, and further containing divinylbenzene or triallyl isocyanurate and other comonomer. The nitrile group of acrylonitrile-based cross-linked polymer introduced with a cross-linked structure by copolymerization of the product is hydrolyzed to form salt-type carboxylic acid. Be those was allowed chemical transformation in group, salt-type carboxyl group of 1.0 mmol / g or more (preferably 2.0 mmol / g or more) moisture-absorbing and desorbing fine particles contained; and the like.

  In addition, in the hygroscopic fine particles of (A), “increase in nitrogen content” means a nitrogen content (% by mass) in the acrylonitrile polymer used as a raw material and a crosslinked structure obtained by treating the resin with a hydrazine compound. It means the difference in nitrogen content (% by mass) after introduction. If the nitrogen content is below the above range, the organic fine particles may be dissolved in the hydrolysis step, and the salt-type carboxyl group may not be introduced. On the other hand, if it exceeds the above range, 1.0 mmol / g or more of the nitrile group may not be converted to a salt-type carboxyl group. In addition, the method of introducing the hydrazine-based crosslinking into the acrylonitrile-based polymer is not particularly limited as long as the increase in the nitrogen content by the crosslinking is 1.0% by mass to 15.0% by mass, but hydrazine is not limited. Industrially preferred is a means for treating an acrylonitrile-based polymer at a temperature of 50 ° C. to 120 ° C. for 0.2 hours to 10 hours using an aqueous solution having a system compound concentration of 1 mass% to 80 mass%.

  A copolymer monomer containing 5% by mass or more of an acrylic acid alkyl ester in addition to the above acrylonitrile-based crosslinked polymer, and further containing divinylbenzene or triallyl isocyanurate, and other copolymer monomers The alkyl ester part of an acrylic acid alkyl ester cross-linked polymer into which a cross-linked structure has been introduced by copolymerization of the composition is chemically converted into a salt-type carboxyl group by hydrolysis. Hygroscopic fine particles containing 0 mmol / g or more can also be preferably used.

  The volume average particle diameter of the hygroscopic fine particles is not particularly limited as long as it does not impair the mechanical properties and the like of the cushion material, and can be appropriately selected depending on the application. However, the smaller the particle size, the larger the surface area of the particle, the higher the moisture absorption rate, and if the particle size is large, the rough surface may not be preferred by consumers, so the volume average particle size is The thickness is preferably 50 μm or less, more preferably 30 μm or less, still more preferably 10 μm or less, and particularly preferably 5 μm or less.

<Binder>
When organic particles are used as the hygroscopic fine particles, the organic particles are inferior in heat resistance and are not suitable for melt kneading into the fiber raw material. Therefore, the hygroscopic fine particles are fixed on the fiber surface using a binder resin ( Preferably).

  When fixing using a binder, the kind of binder resin is not specifically limited. Examples of the binder resin include polyurethane resin, polyester resin, polyamide resin, epoxy resin, phenol resin, acrylic resin, polyvinyl acetate resin, polyolefin resin, and cellulose resin. Among these, polyurethane resins are preferable from the viewpoints of moisture permeability, flexibility, cost, and processability.

  The polyurethane resin is a resin having a urethane bond, and specifically, a conventionally known one such as a polyester type polyurethane, a polyether type polyurethane, a polycarbonate type polyurethane, or a composite polyurethane combining these may be used. it can. Among these, since it is excellent in hydrolysis resistance, a polycarbonate type polyurethane using a polycarbonate polyol as a constituent component is preferable.

  The method for fixing the hygroscopic fine particles to the fiber surface using the binder resin is not particularly limited, and the cushion base is obtained by applying the binder resin to the cushion base material or immersing the cushion base material in the binder resin solution. A method of spraying hygroscopic fine particles after applying a binder to the fiber surface constituting the material and then curing the binder resin; mixing the binder resin and hygroscopic fine particles, and spraying this on the cushion base material, Examples include a method of immersing a cushion base material in a mixed solution and imparting a binder resin and hygroscopic fine particles to the fiber surface constituting the cushion base material, and then curing the binder resin.

  Further, when the hygroscopic fine particles are fixed to the fiber surface using a binder resin, the hygroscopic fine particles are preferably fixed to the fiber surface with a cured porous binder resin. If the cured binder resin is porous, since the cured binder resin can permeate water molecules, moisture absorption by the hygroscopic fine particles is not inhibited and the moisture absorption rate can be further improved. Moreover, if binder resin hardened | cured material is porous, hardened | cured material will become flexible, the texture of the cushion base material after providing a hygroscopic fine particle will be soft, and cushion property will improve more.

  In order to make the cured binder product porous, the binder resin may be cured by a wet coagulation method. Hereinafter, the wet coagulation method will be described taking an example in which a polyurethane resin is used as a binder resin.

  First, a polyurethane resin as a binder resin is dissolved in an organic solvent capable of dissolving the polyurethane resin (hereinafter referred to as “organic solvent A”), and hygroscopic fine particles are added and mixed therein to mix the porous binder solution. To prepare. Examples of the organic solvent A include aprotic polar solvents such as dimethylformamide, dimethylacetamide, dimethyl sulfoxide and N-methylpyrrolidone; halogen solvents such as dichloromethane, chloroform and carbon tetrachloride; ketones such as dimethyl ketone and methyl ethyl ketone. System solvents; cyclic ether solvents such as tetrahydrofuran and dioxane; aromatic organic solvents such as toluene and xylene; and the like. These organic solvents A may be used alone or in combination of two or more. Among these, an aprotic polar solvent is preferable in consideration of the influence on the environment, workability in the wet coagulation method, and simplicity.

  When dissolved in the organic solvent A, the polyurethane resin concentration is preferably 1% by mass to 15% by mass, and 5% by mass to 10% by mass is particularly preferable in consideration of softness. At this time, if the concentration of the polyurethane resin is 1% by mass or more, the strength of the resulting cured porous body is improved and the porous structure is prevented from being crushed. When immersed in the solvent B, the organic solvent A can be easily eluted, and the moisture permeability of the porous layer becomes better.

  The amount of hygroscopic fine particles added is preferably 10 parts by mass or more (more preferably 50 parts by mass or more) with respect to 100 parts by mass of the polyurethane resin. When the amount of the hygroscopic fine particles is 10 parts by mass or more, the hygroscopic fine particles can be sufficiently imparted to the fiber surface, and the hygroscopic rate is further improved.

  And after immersing a cushion base material in the prepared porous binder solution and squeezing an excessive binder solution, it is immersed in a solvent that does not dissolve the polyurethane resin (hereinafter referred to as “solvent B”) and wet-coagulated. . At this time, when immersed in the solvent B, the organic solvent A is eluted in the solvent B, but since the polyurethane resin is not dissolved in the solvent B, the obtained polyurethane resin cured product becomes a porous body. Examples of the solvent B include water.

  The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to the following examples, and may be appropriately modified and implemented within a range that can meet the purpose described above and below. All of which are within the scope of the present invention. In addition, the evaluation method of each characteristic of a cushion material is as follows.

1. Evaluation method 1-1. Air permeability JIS L1096 (2010) 8.26.1 Measured by A method (Fragile method). Specifically, after a test piece cut into 200 mm × 200 mm is attached to one end of a cylinder of a Frazier type tester, a suction fan and an air hole are provided so that an inclination type barometer shows a pressure of 125 Pa by an adjusting resistor. It was adjusted. At this time, the pressure indicated by the vertical barometer was measured, and the measured pressure and the air hole used (46.5, 36.0, 25.7, 18.3, 15.0, 12.0, 11, 8 mm). ), The amount of air passing through the test piece was determined using a conversion table attached to the testing machine. The test was performed 5 times for different test pieces, and the average value was obtained.

1-2. Moisture permeability Measured according to JIS L1099 (2006) A-1. Specifically, 33 g of a hygroscopic agent (calcium chloride) is placed in a moisture permeable cup (a cylindrical shape having a depth of 22 mm and an inner diameter of 60 mm) heated to 40 ° C. so that the distance between the hygroscopic agent and the lower surface of the test piece becomes 3 mm. Adjusted. Next, after placing the test piece cut into a circular shape with a diameter of 70 mm so that the surface faces the hygroscopic agent and concentrically with the moisture permeable cup, the packing and the ring are sequentially attached and fixed. A test specimen was prepared by sealing the mounting side surface with an adhesive tape.
The mass of this test specimen after being left for 1 hour in a constant temperature and humidity chamber set at a temperature of 40 ° C. and a humidity of 90% RH was measured, and the mass after being left for 1 hour in a high temperature and humidity chamber was measured. The moisture permeability per 24 hours per unit area of the test piece was determined from the amount of change in mass of the test specimen.

1-3. Thickness and apparent density of three-dimensional knitted fabric Samples were cut to a size of 15 cm x 15 cm, left to stand for 24 hours at a temperature of 20 ° C and a humidity of 65% RH for 24 hours, and the heights of four locations were measured. Was the thickness.
Moreover, the sample mass after leaving it to stand for 24 hours was measured, and the value obtained by dividing the mass by the sample area (= 0.0225 m ² ) × the sample volume obtained from the thickness was defined as the apparent density.

1-4. Volume average particle size Using a laser diffraction type particle size distribution measuring device (manufactured by Shimadzu Corporation, SALD (registered trademark) -200V), water is measured as a dispersion medium, and the volume average particle size is calculated from the particle size distribution expressed on a volume basis. Asked.

1-5. Amount of salt-type carboxyl group Weigh carefully a well-dried sample (X (g)), add 200 ml of water to it, and then add 1 mol / l hydrochloric acid aqueous solution while heating to 50 ° C to pH 2. Thus, all the carboxyl groups contained in the sample were H-type carboxyl groups. Then, a titration curve was obtained according to a conventional method using a 0.1 mol / l NaOH aqueous solution. From the titration curve, the consumption amount of NaOH aqueous solution consumed in the H-type carboxyl groups (Y (ml)) was determined, and the total amount of carboxyl groups contained in the sample was calculated by the following formula.
Total amount of carboxyl groups (mmol / g) = 0.1 × Y / X
Separately, a titration curve was similarly obtained without adjusting to pH 2 by adding a 1 mol / l hydrochloric acid aqueous solution during the above-described total carboxyl group amount measurement operation, and the amount of H-type carboxyl groups contained in the sample was obtained. From these results, the salt-type carboxyl group amount was calculated by the following formula.
Salt-type carboxyl group amount (mmol / g) = (total carboxyl group amount) − (H-type carboxyl group amount)

1-6. Moisture absorption rate A sample was cut into a size of 15 cm × 15 cm to prepare a test piece. The test piece was allowed to stand for 24 hours in an environment of a temperature of 33 ° C. and a humidity of 40% RH, and then the humidity-controlled test piece was left for 30 minutes in an environment of a temperature of 33 ° C. and a humidity of 80% RH for moisture absorption. I let you. The mass absorption per unit time is determined from the difference between the mass of the test piece immediately after conditioning and the mass of the test piece after moisture absorption and the moisture absorption time (30 minutes), and the mass absorption per unit time is calculated as the volume of the test piece. The moisture absorption rate was calculated by dividing.
The volume of the test piece was left at 24 ° C. for 24 hours at a temperature of 20 ° C. and a humidity of 65% RH, and then the height of four locations was measured, and the average value was thickness × sample area (= 0.0225 m ² ). Determined by

1-7. Evaluation of sensation by perspiration simulator Perspiration simulator Using a skin model, the hot plate temperature was 37 ° C., the perspiration amount was 200 g / m ² · h, the sample and the hot plate were brought into close contact, and the absolute humidity between the sample and the hot plate was measured. Specifically, the temperature was stabilized for 10 minutes without sweating, then sweating was performed for 20 minutes, and the absolute humidity after 20 minutes was measured.
The effect of reducing the sensation of the sample was evaluated as “◯” when the absolute humidity after 20 minutes was smaller than 20 mmHg, “Δ” when 20 mmHg or more and less than 25 mmHg, and “X” when 25 mmHg or more.
The sweat simulator is a heat production sweating mechanism comprising a substrate having a sweat hole and a heat producing body, a water supply mechanism for supplying water to the sweat hole, a heat production control mechanism for controlling the temperature of the heat producing body, and a temperature / humidity sensor. It is composed of The substrate is made of brass, has an area of 120 cm ² , is provided with six sweat holes, and is controlled at a constant temperature by a heat-producing body composed of a planar heater. The water supply mechanism uses a tube pump, and sends out a constant amount of water to the sweat holes of the substrate. Simulated skin made of a polyester multifilament fabric is affixed to the surface of the substrate, whereby water discharged from the sweat holes is spread on the surface of the substrate and a sweating state is created. A temperature / humidity sensor protected in a 2 mm thick case with a simulated skin affixed to the surface of the substrate is installed between the hot plate and the sample. Measure the humidity in the space surrounded by the hot plate, sample, and case.

1-8. Cushion evaluation by a monitor test Ten monitors were asked to evaluate the cushion characteristics when lying on the cushion material for 5 minutes. Based on the evaluation results of 10 monitors, “◯” indicates that the cushioning property is excellent, “△” indicates that the cushioning property is slightly inferior, and “×” indicates that the cushioning property is inferior.

2. 2. Production of cushion base material 2-1. Double raschel fabric Front boss 1,2, 167 dtex / 48 filament polyester yarn manufactured according to the usual method is placed in a 1-in-3-out yarn feeder, and 330 tex / one filament is placed on the middle osas 3 and 4, which are connected yarns. Polyester fiber (Diaflora (registered trademark) CS0330, manufactured by Toyobo Co., Ltd.) is placed in a 1-in-3 out yarn holder, and 167 dtex / 48-filament polyester yarn manufactured according to a conventional method is used for back fiber 5 and 6. A double raschel knitted fabric with a mesh on the front and back was prepared using a 22 gauge 6 sheet osserable raschel knitting machine with an on-machine course of 35 courses / inch.
The knitting runner (the amount of yarn necessary for knitting 480 courses) at this time was as follows.
Front Osa 1: 198cm / Rack Front Osa 2: 198cm / Rack Middle Osa 3: 850cm / Rack Middle Osa 4: 850cm / Rack Back Osa 5: 170cm / Rack Back Osa 6: 108cm / Rack Finishing with this raw machine Thus, a double raschel fabric having a finishing course of 37 courses / inch, 23 wales / inch, a width of 148 cm, and a basis weight of 333 g / m ² was obtained. The mesh knitted fabrics on the front and back sides have a hexagonal mesh shape, a maximum mesh diameter of 4.1 mm, and a knitted fabric width between the meshes of 1.7 mm.

2-2. Polyester spunbond nonwoven fabric Polyester span having a basis weight of 130 g / m ² and a thickness of 1.7 mm by a needle punch method using staples made of 100% by mass of polyester short fibers (manufactured by Toyobo Co., Ltd., fineness 2.4 dtex, fiber length 38 mm). A bond nonwoven fabric was produced.

3. Production of hygroscopic fine particles 3-1. Acrylic crosslinked polymer hygroscopic fine particles A
450 parts by mass of acrylonitrile, 50 parts by mass of methyl acrylate and 1181 parts by mass of water were charged into a 2 liter autoclave, and 2.5 parts by mass of di-tert-butyl peroxide as a polymerization initiator (total amount of monomers 100 masses). 0.5 parts by mass relative to parts). The autoclave was sealed and polymerized at a temperature of 120 ° C. for 30 minutes under stirring. After completion of the reaction, the mixture was cooled to 90 ° C. while continuing stirring to obtain polymer particles having a volume average particle diameter of 2 μm.
Next, 60 parts by mass of 60% hydrazine and 850 parts by mass of water were mixed with 100 parts by mass of the obtained polymer particles, and a crosslinked structure was introduced by performing hydrazine treatment at 90 ° C. for 3 hours. Furthermore, 112 parts by mass of sodium hydroxide was added, and the reaction was carried out at 120 ° C. for 2 hours. The obtained particles were washed with water, washed and dried, and classified to obtain acrylic crosslinked polymer hygroscopic fine particles A having a volume average particle diameter of 4 μm. The amount of the salt-type carboxyl group of the particles was 7.0 mmol / g.

3-2. Acrylic cross-linked polymer hygroscopic fine particles B
A monomer mixture consisting of 55 parts by mass of acrylonitrile, 10 parts by mass of methyl acrylate, and 35 parts by mass of divinylbenzene was added to 300 parts by mass of an aqueous solution containing 0.5 parts by mass of ammonium persulfate, and then 0.6 parts by mass of sodium pyrosulfite. And polymerized at 65 ° C. for 2 hours in a polymerization tank equipped with a stirrer. 15 parts by mass of the obtained particles are dispersed in 85 parts by mass of water, 10 parts by mass of sodium hydroxide are added thereto, and after performing a hydrolysis reaction at 90 ° C. for 2 hours, washing, dehydration and drying are performed. Acrylic crosslinked polymer hygroscopic fine particles B were obtained. The particles had a volume average particle size of 50 μm and a salt-type carboxyl group content of 6.3 mmol / g.

3-3. 1000 g of pure water was charged into a 5 L separable flask (with a jacket) made of silica gel glass and having a water-cooled condenser open to the atmosphere attached to the top. While stirring at 80 rpm, 1400 g of tetramethoxysilane was charged into this over 3 minutes. The water / tetramethoxysilane molar ratio is about 6/1. Warm water at 50 ° C. was passed through the jacket of the separable flask. Stirring was continued, and the stirring was stopped when the contents reached the boiling point. Subsequently, hot water at 50 ° C. was passed through the jacket for about 0.5 hour to gel the purified sol.
Thereafter, the gel was quickly taken out, and the gel was pulverized through a nylon net having an opening of 600 μm to obtain a powdery wet gel (silica hydrogel). 450 g of this hydrogel and 450 g of pure water were charged into a 1 L glass autoclave and hydrothermally treated at 180 ° C. for 3 hours. Thereafter, the liquid was cut through a nylon net having a mesh size of 100 μm, and dried under reduced pressure at 160 ° C. until it became a constant weight without washing the filter cake with water.
The obtained silica gel was pulverized with a pulverizer (manufactured by Hosokawa Micron Corporation, AFG-200 type), and further air classification was performed to obtain a silica gel having a volume average particle diameter of 5 μm.

4). Hygroscopic cushion material 4-1. Example 1
A porous binder solution was prepared by mixing 10 parts by mass of acrylic crosslinked polymer hygroscopic fine particles A, 10 parts by mass of polycarbonate polyurethane as a binder resin, and 90 parts by mass of dimethylformamide (organic solvent A).
After immersing the double raschel dough in the binder solution prepared above and squeezing it with a mangle adjusted to a pressure of 0.3 MPa, it is immersed in water (solvent B) at 25 ° C. for 4 minutes to cure the binder resin. A cured porous binder was obtained. Furthermore, after immersing in warm water at 40 ° C. for 15 minutes, rinsing excess organic solvent A (dimethylformamide), and squeezing excess solvent B (water) with a mangle adjusted to a pressure of 0.3 MPa, It dried for 5 minutes with the 130 degreeC dryer, and produced the moisture-permeable permeability material. In the obtained hygroscopic cushion material, hygroscopic fine particles were fixed to the fiber surface constituting the cushion base material with a cured porous binder.

4-2. Example 2
A hygroscopic cushion material was prepared in the same manner as in Example 1 except that the hygroscopic fine particles were changed to 10 parts by mass of the acrylic crosslinked polymer hygroscopic fine particles B10. In the obtained hygroscopic cushion material, hygroscopic fine particles were fixed to the fiber surface constituting the cushion base material with a cured porous binder.

4-3. Comparative Example 1
35 parts by mass of silica gel, 100 parts by mass of a polycarbonate-type polyurethane emulsion (solid content concentration 35% by mass) as a binder, 250 parts by mass of water, 2 parts by mass of a carbodiimide-based crosslinking agent, and 0.1 parts by mass of a silicone-based antifoaming agent are mixed. A polyurethane resin solution was prepared.
A double raschel fabric was immersed in the polyurethane resin solution prepared as described above, and after squeezing with a mangle whose pressure was adjusted to 0.3 MPa, it was dried with a dryer at 130 ° C. to produce a moisture-absorbent cushion material. . In the obtained moisture-permeable cushioning material, hygroscopic fine particles were fixed to the fiber surface constituting the cushion base material by the cured binder, but the cured binder was not porous.

4-4. Comparative Example 2
Double raschel fabric was used as it was as a moisture permeable cushion material.

4-5. Comparative Example 3
A hygroscopic cushion material was prepared in the same manner as in Comparative Example 1 except that the hygroscopic fine particles were changed to 35 parts by mass of the acrylic crosslinked polymer hygroscopic fine particles A. In the obtained moisture-permeable cushioning material, hygroscopic fine particles were fixed to the fiber surface constituting the cushion base material by the cured binder, but the cured binder was not porous.

4-6. Comparative Example 4
A polyester spunbond nonwoven fabric prepared by mixing a mixture (mass ratio = 85/15) of acrylic crosslinked polymer hygroscopic fine particles A and ethylene-acrylic copolymer particles (melting point 106 ° C., volume average particle diameter 10 μm) using a powder coating machine. after the coated amount was coated to a 1000 g / m ^2, and further laminating a polyester spunbonded nonwoven fabric from above, by using a laminator at 0.99 ° C., it was bonded laminate.

4-7. Comparative Example 5
A hygroscopic cushioning agent was produced in the same manner as in Example 1 except that the cushion base material was changed to slab urethane having a thickness of 10 mm and a basis weight of 245 g / m ² .

  The moisture-permeable and cushioning materials produced in the examples and comparative examples were evaluated, and the results are shown in Table 1.

  From comparison between Examples 1 and 2 and Comparative Example 1, in Examples 1 and 2 using organic hygroscopic fine particles A and B having chemical adsorption action, inorganic hygroscopic fine particles having physical adsorption action are used. It can be seen that the moisture absorption rate per unit volume is very high as compared with Comparative Example 1 using No. 1, and is excellent in the effect of reducing the sensation of feeling. This is because organic hygroscopic fine particles having a chemical adsorption action have a higher hygroscopic rate than inorganic hygroscopic fine particles having a physical adsorption action.

  From the comparison between Examples 1 and 2 and Comparative Example 2, Examples 1 and 2 in which hygroscopic fine particles were added to the double raschel dough were more hygroscopic per unit volume than Comparative Example 2 which was an unprocessed double raschel dough. It becomes very high, and it turns out that it is excellent in the reduction effect of a feeling of peeling.

From a comparison between Example 1 and Comparative Example 3, Example 1 in which the cured binder was porous had a higher moisture absorption rate per unit volume than in Comparative Example 3 in which the cured binder was non-porous, and was not peeled. It turns out that it is excellent in the feeling reduction effect. This is because the porous cured binder layer formed by the wet process has a high moisture permeability, so that it is difficult to prevent the hygroscopic performance of the hygroscopic fine particles.
In addition, the cured porous binder was more flexible than the nonporous material, and the cushioning property of the moisture-absorbent cushioning material was excellent without impairing the texture of the cushion base material.

From comparison between Examples 1 and 2 and Comparative Example 4, Examples 1 and 2 in which hygroscopic fine particles were added to the double raschel fabric were more per unit volume than Comparative Example 4 in which the hygroscopic fine particles were sandwiched between polyester spunbond nonwoven fabrics. It can be seen that the moisture absorption rate of is extremely high, and is excellent in the effect of reducing the feeling of peeling.
The hygroscopic cushion materials of Examples 1 and 2 can sufficiently exhibit the hygroscopic performance of the hygroscopic fine particles inside the cushion base material by imparting hygroscopic fine particles to the double raschel fabric having high moisture permeability. On the other hand, since the moisture permeability of the nonwoven fabric is low in Comparative Example 4, only the hygroscopic fine particles close to the cushion base material contribute to moisture absorption, and the hygroscopic performance of the internal hygroscopic particles was not sufficiently exhibited. There was a difference in the effect of reducing the sensation. The polyester spunbonded nonwoven fabric was thin and inferior in cushioning properties.

  From the comparison between Examples 1 and 2 and Comparative Example 5, Examples 1 and 2 in which hygroscopic fine particles were imparted to the double raschel dough, moisture absorption per unit volume compared to Comparative Example 5 in which hygroscopic fine particles were imparted to slab urethane It can be seen that the speed is very high and the effect of reducing the sensation is excellent. Since slab urethane has low air permeability and moisture permeability and moisture hardly permeates through the cushion base material, it is considered that the hygroscopic performance of the hygroscopic fine particles was hindered. In addition, since slab urethane has low air permeability, when applying hygroscopic fine particles, the treatment liquid did not sufficiently penetrate into the cushion base material, and hygroscopic fine particles were hardly given inside the cushion base material. It is thought that the moisture absorption rate is low.

  Since the moisture-permeable cushion material of the present invention is excellent in moisture absorption speed, breathability, moisture permeability, and cushioning properties, it is useful for bedding materials such as beds and cushion materials for automobile and train seats.

Claims (5)

A moisture permeable cushioning material having a cushion base material made of fibers and hygroscopic fine particles fixed to the fiber surface constituting the cushion base material,
The cushion base material composed of the fibers is a double knitted fabric composed of two ground structures, and a connecting yarn that connects the two ground structures.
A moisture-permeable cushioning material characterized in that the moisture-absorbing cushion material itself has a moisture absorption rate of 50 g / m ³ · min or more per unit volume and an air permeability of 100 cm ³ / cm ² · s or more. The hygroscopic cushion material according to claim 1, wherein the hygroscopic fine particles are fixed to the fiber surface with a cured porous binder resin. The hygroscopic cushion material according to claim 1 or 2 , wherein the hygroscopic fine particles contain 1.0 mmol / g or more of a salt-type carboxyl group. The hygroscopic cushion material according to any one of claims 1 to 3 , wherein the hygroscopic fine particles have a volume average particle diameter of 50 µm or less. After immersing the cushion base material in a binder resin solution and applying the binder resin to the fiber surface constituting the cushion base material, spraying hygroscopic fine particles, and then curing the binder resin, or
A binder resin and hygroscopic fine particles are mixed, and the cushion base material is immersed in the mixed solution to give the binder resin and hygroscopic fine particles to the fiber surface constituting the cushion base material, and then the binder resin is cured. ,
Accordingly, the hygroscopic cushion material according to any one of claims 1 to 4, wherein the hygroscopic fine particles are fixed to a fiber surface constituting the cushion base material.