WO2015129602A1

WO2015129602A1 - Sheet-like material and method for producing same

Info

Publication number: WO2015129602A1
Application number: PCT/JP2015/054941
Authority: WO
Inventors: 寿村原; 俊一郎中井; 貴大土本
Original assignee: 東レ株式会社
Priority date: 2014-02-27
Filing date: 2015-02-23
Publication date: 2015-09-03
Also published as: JP6551227B2; KR102297654B1; TWI711660B; EP3112530B1; US20160362832A1; EP3112530A4; EP3112530A1; JPWO2015129602A1; CN106029976A; CN106029976B; TW201542635A; KR20160127019A; US20200149216A1

Abstract

The present invention pertains to a method for manufacturing a sheet-like material without using an organic solvent in the manufacturing process, and provides a sheet-like material having excellent surface quality and texture and a method for manufacturing the same. This sheet-like material is formed by adding, as a binder, a polymer elastomer having a hydrophilic group to a fibrous base material comprising ultra-fine fibers, wherein, in a cross-section of the sheet-like material that is cut in the thickness direction, the occupancy ratio of a portion of the polymer elastomer observed within the cut surface, the portion independently having a cross-sectional area of 50 μm2 or more, is 0.1-5.0% inclusive with respect to the area of an artificial leather cross-section within the observation visual field. This method for manufacturing the sheet-like material comprises adding, as a binder, a polymer elastomer having a hydrophilic group to a fibrous base material comprising ultra-fine fibers, wherein a polymer elastomer dispersed in water and an aqueous resin dispersion containing a thickener are added to a fibrous base material, and the polymer elastomer is coagulated in hot water at a temperature of 50-100℃.

Description

Sheet material and method for producing the same

The present invention relates to a method for producing an environmentally friendly sheet material that does not use an organic solvent in the production process, and particularly relates to a sheet material having good surface quality and texture and a method for producing the same.

A sheet-like material mainly composed of a fibrous base material such as nonwoven fabric and polyurethane has excellent characteristics not found in natural leather, and is widely used in various applications such as artificial leather. In particular, sheet-like materials using a polyester-based fibrous base material are excellent in light resistance, and therefore their use has been expanded year by year for use in clothing, chair upholstery and automobile interior materials.

In manufacturing such a sheet-like material, after impregnating the fibrous base material with an organic solvent solution of polyurethane, the obtained fibrous base material is immersed in water or an organic solvent aqueous solution which is a non-solvent of polyurethane. A combination of processes for wet coagulation of polyurethane is generally employed. In this case, a water-miscible organic solvent such as N, N-dimethylformamide is used as the organic solvent that is a solvent for the polyurethane. However, since organic solvents are generally highly harmful to the human body and the environment, a technique that does not use organic solvents is strongly demanded in the production of sheet-like materials.

As a specific solution, a method using a water-dispersed polyurethane in which a hydrophilic group is contained in a molecule and a polyurethane resin is dispersed in water has been studied in place of a conventional organic solvent-based polyurethane.

However, a sheet-like material obtained by impregnating a fibrous base material with a water-dispersed polyurethane dispersion in which water-dispersed polyurethane is dispersed in a liquid and solidifying the polyurethane has a problem that the texture tends to be hard.

】 One of the main reasons is the difference between the two coagulation methods. That is, the coagulation method of the organic solvent-based polyurethane liquid is a so-called wet coagulation method in which polyurethane molecules dissolved in the organic solvent are replaced with water to coagulate, and when viewed as a polyurethane film, the porous film has a low density. Is formed. Therefore, even when polyurethane is impregnated in the fibrous base material and solidified, the bonding area between the fiber and the polyurethane is reduced, resulting in a soft sheet.

On the other hand, water-dispersed polyurethane mainly uses a so-called wet heat coagulation method in which the hydration state of the water-dispersed polyurethane dispersion is disrupted by heating and solidifies by agglomerating polyurethane emulsions. The resulting polyurethane film structure is a non-porous film having a high density. Therefore, the adhesion between the fibrous base material and the polyurethane becomes dense, and the entangled portion of the fiber is strongly gripped, so that the texture becomes hard.

In order to improve the texture by applying this water-dispersed polyurethane, that is, to suppress the gripping of fiber entanglement points by polyurethane, a technique for making the structure of polyurethane in a fibrous base material porous is proposed.

Specifically, a water-dispersed polyurethane liquid containing a foaming agent is applied to a fibrous base material such as a nonwoven fabric, and the foaming agent is foamed by heating to make the polyurethane structure in the fibrous base material porous. A method has been proposed (see Patent Document 1). In this proposal, by making the water-dispersible polyurethane porous, the adhesive area between the fiber and polyurethane is reduced, the gripping force of the fiber entanglement point is weakened, and a sheet-like material having a good texture that is soft to the touch. Although it can be obtained, it tends to be poor in flexibility as compared with the case where the organic solvent-based polyurethane is applied.

Separately, as a technology for making the structure of polyurethane in a fibrous base material porous, a water-dispersible polyurethane dispersion containing an associative thickener is applied to the fibrous base material and coagulated with heat and moisture. A method for making water-dispersible polyurethane porous has been proposed (see Patent Document 2). Also in this proposal, by making the water-dispersible polyurethane porous, the adhesive area between the fiber and the polyurethane is reduced, the gripping force at the entanglement point of the fiber is weakened, and the sheet-like material having a good texture that is soft to the touch. However, as compared with the case where the organic solvent-based polyurethane is applied, the flexibility is still poor.

JP 2011-214210 A Japanese Patent No. 4042016

Therefore, in view of the background of the above-mentioned prior art, the object of the present invention is a uniform feeling comparable to artificial leather to which organic solvent-based polyurethane is applied by an environmentally friendly manufacturing process, and has an elegant surface quality and good texture. It is in providing the sheet-like material which has this, and its manufacturing method.

Furthermore, an object of the present invention is to achieve a porous structure of polyurethane by applying water-dispersed polyurethane, and to have a sheet-like material having a crease recovery property and flexibility very similar to artificial leather to which solvent-based polyurethane is applied. And providing a manufacturing method thereof.

The present invention is to achieve the above-mentioned problem, and the sheet-like material of the present invention is a polymer elastic body having a hydrophilic group on a fibrous base material composed of ultrafine fibers and / or ultrafine fiber bundles. Is a sheet-like material provided as a binder, and in the cross-section cut in the thickness direction of the sheet-like material, among the polymer elastic bodies observed in the cut surface, independently 50 μm ² or more The sheet-like product is characterized in that the occupation ratio of the portion having the cross-sectional area is 0.1% or more and 5.0% or less with respect to the area of the cross section of the artificial leather in the observation visual field.

According to a preferred embodiment of the sheet-like material of the present invention, in the cross-section cut in the thickness direction of the sheet-like material, 1% or more and 35% or less of the outer periphery of the cross-section of the ultrafine fiber and / or ultrafine fiber bundle is a polymer elastic body. It is covered with a film.

According to a preferred aspect of the sheet-like material of the present invention, the sheet-like material according to claim 1 or 2, wherein the polymer elastic body has a structure crosslinked by a crosslinking agent.

The present invention is intended to achieve the above-described object, and in the method for producing a sheet-like material of the present invention, a polymer elastic body having a hydrophilic group is applied as a binder to a fibrous base material composed of ultrafine fibers. In the method for producing a sheet-like product thus formed, an aqueous resin dispersion containing a polymer elastic body and a thickener dispersed in water is applied to a fibrous base material, and is heated in hot water at a temperature of 50 to 100 ° C. A method for producing a sheet-like material, comprising solidifying the polymer elastic body.

According to a preferred embodiment of the method for producing a sheet-like material of the present invention, the aqueous resin dispersion is non-Newtonian.

According to a preferred embodiment of the method for producing a sheet-like material of the present invention, the thickener is a nonionic thickener.

According to a preferred embodiment of the method for producing a sheet-like material of the present invention, the aqueous resin dispersion is to exhibit thixotropic properties.

According to a preferred embodiment of the method for producing a sheet-like material of the present invention, the thickener contained in the aqueous resin dispersion is a thickening polysaccharide.

According to a preferred embodiment of the method for producing a sheet-like product of the present invention, the thickener is guar gum.

According to a preferred embodiment of the method for producing a sheet-like material of the present invention, the aqueous resin dispersion contains a heat-sensitive coagulant.

According to a preferred embodiment of the method for producing a sheet-like material of the present invention, the aqueous resin dispersion contains a crosslinking agent.

According to the present invention, a water-dispersed polyurethane is made porous by an environmentally-friendly manufacturing process, and a wrinkle recovery property and flexibility very similar to those obtained when an organic solvent-based polyurethane is applied to a fibrous base material are achieved. In addition, it has a uniform raised length equivalent to artificial leather to which organic solvent-based polyurethane is applied, and has an elegant surface quality excellent in fiber denseness and a soft texture that is flexible and excellent in wrinkle recovery. Is obtained.

FIG. 1 is a drawing-substituting SEM photograph of a cross section of artificial leather obtained in Example 13 of the present invention. FIG. 2 is an SEM photograph substituting for a drawing of a cross section of the artificial leather obtained in Comparative Example 4 of the present invention. FIG. 3 is a drawing-substituting reference SEM photograph for explaining an outline of a method for calculating the occupation ratio of a non-porous mass of a polymer elastic body of 50 μm ² or more. FIG. 4 is a drawing-substituting reference SEM photograph for explaining a method of calculating the polymer elastic body coating ratio of the ultrafine fiber cross section.

[About sheet-like materials]
First, the sheet-like material of the present invention will be described.

The sheet-like material of the present invention is obtained by applying a polymer elastic body made of a hydrophilic group-containing resin such as water-dispersed polyurethane as a binder to a fibrous base material such as a nonwoven fabric made of ultrafine fibers.

Examples of fibers constituting the fibrous base material include polyethylene terephthalate, polybutylene terephthalate, polyester such as polytrimethylene terephthalate and polylactic acid, polyamide such as 6-nylon and 66-nylon, acrylic, polyethylene, polypropylene, and thermoplastic cellulose. Examples thereof include fibers made of a thermoplastic resin that can be melt-spun. Among these, polyester fibers are preferably used from the viewpoints of strength, dimensional stability, and light resistance. The fibrous base material may be configured by mixing fibers of different materials.

As the cross-sectional shape of the ultrafine fiber, a round cross-section may be used, but a cross-sectional shape having a polygonal shape such as an ellipse, a flat shape, and a triangle, a cross-sectional shape such as a sector shape and a cross shape may be employed.

The average single fiber diameter of the ultrafine fibers constituting the fibrous base material is preferably 0.1 to 7 μm. By setting the average single fiber diameter to preferably 7 μm or less, more preferably 6 μm or less, and even more preferably 5 μm or less, a sheet-like product having excellent flexibility and napping quality can be obtained. On the other hand, the average single fiber diameter is preferably 0.1 μm or more, more preferably 0.3 μm or more, still more preferably 0.7 μm or more, and particularly preferably 1 μm or more. Excellent dispersibility and ease of handling of bundled fibers during napping such as grinding.

Woven fabrics, knitted fabrics, non-woven fabrics and the like can be adopted as the form of the fibrous base material made of ultrafine fibers. Especially, since the surface quality of the sheet-like thing at the time of surface raising treatment is favorable, a nonwoven fabric is used preferably.

As the nonwoven fabric, either a short fiber nonwoven fabric or a long fiber nonwoven fabric is used, but a short fiber nonwoven fabric is preferably used in terms of texture and quality.

The fiber length of the short fibers in the short fiber nonwoven fabric is preferably 25 mm or more and 90 mm or less, more preferably 35 mm or more and 75 mm or less. By setting the fiber length to 25 mm or more, a sheet-like material having excellent abrasion resistance can be obtained by entanglement. In addition, when the fiber length is 90 mm or less, it is possible to obtain a sheet-like product having a better texture and quality.

When the fibrous base material made of ultrafine fibers is a non-woven fabric, the non-woven fabric preferably has a structure in which ultrafine fiber bundles (fiber bundles) are intertwined. Since the ultrafine fibers are entangled in a bundle state, the strength of the sheet-like material is improved. The nonwoven fabric of such an embodiment can be obtained by causing the ultrafine fibers to develop after entanglement of the ultrafine fiber-expressing fibers in advance.

When ultrafine fibers or fiber bundles constitute a nonwoven fabric, a woven fabric or a knitted fabric can be inserted into the nonwoven fabric for the purpose of improving the strength. The average single fiber diameter of the fibers constituting such a woven or knitted fabric is preferably about 0.1 to 10 μm.

In the sheet-like product of the present invention, the hydrophilic group-containing resin that is an elastic polymer used as a binder includes water-dispersed silicone resins, water-dispersed acrylic resins, water-dispersed urethane resins and copolymers thereof. Among them, water-dispersed polyurethane is preferably used from the viewpoint of texture.

As the polyurethane, a resin obtained by a reaction between a polymer polyol having a number average molecular weight of preferably 500 or more and 5000 or less, an organic polyisocyanate, and a chain extender is preferably used. In order to improve the stability of the water-dispersed polyurethane dispersion, an active hydrogen component-containing compound having a hydrophilic group is used in combination. By setting the number average molecular weight of the polymer polyol to 500 or more, more preferably 1500 or more, it is possible to prevent the texture from becoming hard, and by setting the number average molecular weight to 5000 or less, more preferably 4000 or less. The strength as polyurethane as a binder can be maintained.

As the polyether polyol in the above-mentioned polymer polyol, monomers such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, tetrahydrofuran, epichlorohydrin, and cyclohexylene are added and polymerized using polyhydric alcohol or polyamine as an initiator. And polyols obtained by ring-opening polymerization of the above monomers using a protonic acid, a Lewis acid, a cationic catalyst or the like as a catalyst. Specific examples include polyethylene glycol, polypropylene glycol, polytetramethylene glycol and the like, and copolymerized polyols combining them.

Examples of the polyester-based polyol include polyester polyols obtained by condensing various low molecular weight polyols and polybasic acids, polyols obtained by open polymerization of lactones, and the like.

Examples of the low molecular weight polyol include ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1.8- Linear alkylene glycol such as octanediol, 1,9-nonanediol, 1,10-decanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentane Diols, branched alkylene glycols such as 2-methyl-1,8-octanediol, alicyclic diols such as 1,4-cyclohexanediol, and aromatic divalents such as 1,4-bis (β-hydroxyethoxy) benzene 1 type or 2 types or more chosen from alcohol etc. are mentioned. Further, an adduct obtained by adding various alkylene oxides to bisphenol A can also be used as a low molecular weight polyol.

Polybasic acids include, for example, succinic acid, maleic acid, adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, and hexahydro 1 type, or 2 or more types chosen from isophthalic acid etc. are mentioned.

Examples of the polylactone polyol include polylactone polyol obtained by ring-opening polymerization of γ-butyrolactone, γ-valerolactone, ε-caprolactone, etc., alone or in a mixture of two or more, using polyhydric alcohol as an initiator.

Examples of the polycarbonate-based polyol include compounds obtained by a reaction between a polyol and a carbonate compound such as dialkyl carbonate or diaryl carbonate.

As the polyol used as the raw material for producing the polycarbonate polyol, the polyols mentioned as the raw material for producing the polyester polyol can be used. As the dialkyl carbonate, dimethyl carbonate, diethyl carbonate and the like can be used, and as the diaryl carbonate, diphenyl carbonate and the like can be mentioned.

In the polymer elastic body having a hydrophilic group used in the present invention, examples of the component for allowing the polymer elastic body to contain a hydrophilic group include a hydrophilic group-containing active hydrogen component. Examples of the hydrophilic group-containing active hydrogen component include compounds containing a nonionic group and / or an anionic group and / or a cationic group and active hydrogen. As the compound having a nonionic group and active hydrogen, a compound containing two or more active hydrogen components or two or more isocyanate groups and having a polyoxyethylene glycol group having a molecular weight of 250 to 9000 in the side chain, And triols such as trimethylolpropane and trimethylolbutane.

Examples of the compound having an anionic group and active hydrogen include carboxyl group-containing compounds such as 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid and 2,2-dimethylolvaleric acid, and derivatives thereof. Compounds containing sulfonic acid groups such as 1,3-phenylenediamine-4,6-disulfonic acid, 3- (2,3-dihydroxypropoxy) -1-propanesulfonic acid and their derivatives, and these compounds Examples include salts neutralized with a neutralizing agent.

Further, examples of the compound containing a cationic group and active hydrogen include tertiary amino group-containing compounds such as 3-dimethylaminopropanol, N-methyldiethanolamine, and N-propyldiethanolamine, and derivatives thereof.

The hydrophilic group-containing active hydrogen component can also be used in the form of a salt neutralized with a neutralizing agent.

From the viewpoint of mechanical strength and dispersion stability of the polyurethane resin, the hydrophilic group-containing active hydrogen component used in the polyurethane molecule is 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, and among them. It is preferable to use a Japanese salt.

Introducing a hydroxyl group, a sulfonic acid group, a carboxyl group, etc. among the above-mentioned hydrophilic group-containing active hydrogen components to the polyurethane, in addition to enhancing the hydrophilicity of the polyurethane molecule, and using a crosslinking agent described later together Thus, a three-dimensional crosslinked structure can be imparted to the polyurethane molecule and the physical properties can be improved. Therefore, the hydrophilic group-containing active hydrogen component is preferably selected and manufactured.

As the chain extender, a compound used in conventional production of polyurethane can be used, and among them, a low molecular weight compound having a molecular weight of 600 or less having two or more active hydrogen atoms capable of reacting with an isocyanate group in the molecule is preferably used. It is done. Specifically, ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,4-cyclohexanediol, xylylene glycol Diols such as, triols such as trimethylolpropane and trimethylolbutane, hydrazine, ethylenediamine, isophoronediamine, piperazine, 4,4'-methylenedianiline, tolylenediamine, xylylenediamine, hexamethylenediamine, 4, Examples thereof include diamines such as 4′-dicyclohexylmethanediamine, triamines such as diethylenetriamine, and amino alcohols such as aminoethyl alcohol and aminopropyl alcohol.

Examples of organic polyisocyanates include aliphatic diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate (hereinafter abbreviated as IPDI), hydrogenated xylylene diisocyanate, dicyclohexylmethane diisocyanate (hereinafter abbreviated as hydrogenated MDI). ), Aromatic / aliphatic diisocyanates such as xylylene diisocyanate (hereinafter abbreviated as XDI) and tetramethyl-m-xylylene diisocyanate, and tolylene diisocyanate Isocyanate (hereinafter sometimes abbreviated as TDI), 4,4′-diphenylmethane diisocyanate (hereinafter sometimes abbreviated as MDI), tolidine diisocyanate, and naphthalene diisocyanate (hereinafter referred to as “MDI”) , NDI, etc.)) and the like.

By introducing a sulfonic acid group, a carboxyl group, a hydroxyl group, or a primary or secondary amino group into the polyurethane used in the present invention and allowing the polyurethane dispersion to contain a crosslinking agent having reactivity with these functional groups, the reaction is carried out. Later, the resin has a high molecular weight and the crosslink density of the resin increases. For this reason, durability, a weather resistance, heat resistance, and the strong retention rate at the time of wetness can further be improved.

As the cross-linking agent, a cross-linking agent having two or more reactive groups in the molecule that can react with the reactive group introduced into the polyurethane can be used. Specifically, polyisocyanate crosslinking agents such as water-soluble isocyanate compounds and block isocyanate compounds, melamine crosslinking agents, oxazoline crosslinking agents, carbodiimide crosslinking agents, aziridine crosslinking agents, epoxy crosslinking agents and hydrazine crosslinking agents These crosslinking agents can be mentioned. A crosslinking agent may be used individually by 1 type, and can also use 2 or more types together.

The water-soluble isocyanate compound has two or more isocyanate groups in the molecule, and examples thereof include the above-mentioned organic polyisocyanate-containing compounds. Examples of commercially available products include “Baihijoule” (registered trademark) series and “Death Module” (registered trademark) series manufactured by Bayer MaterialScience.

The blocked isocyanate compound has two or more blocked isocyanate groups in the molecule. The blocked isocyanate group means a group obtained by blocking the organic polyisocyanate compound with a blocking agent such as alcohols, amines, phenols, imines, mercaptans, pyrazoles, oximes and active methylenes. The commercial products include “Elastoron” (registered trademark) series of Daiichi Kogyo Seiyaku Co., Ltd., “Duranate” (registered trademark) series manufactured by Asahi Kasei Chemicals Corporation, and “Takenate” (manufactured by Mitsui Chemicals, Inc.). Registered trademark) series and the like.

Examples of the melamine-based crosslinking agent include compounds having two or more methylol groups or methoxymethylol groups in the molecule. Commercially available products include “Uban” (registered trademark) series manufactured by Mitsui Chemicals, “Cymel” (registered trademark) series manufactured by Nippon Cytec Co., Ltd., and “Sumimar” (registered trademark) manufactured by Sumitomo Chemical Co., Ltd. ) Series.

Examples of the oxazoline-based crosslinking agent include compounds having two or more oxazoline groups (oxazoline skeletons) in the molecule. Examples of commercially available products include “Epocross” (registered trademark) series manufactured by Nippon Shokubai Co., Ltd. Examples of the carbodiimide-based crosslinking agent include compounds having two or more carbodiimide groups in the molecule. Examples of the commercial products include “Carbodilite” (registered trademark) series manufactured by Nisshinbo Industries, Ltd.

Examples of the epoxy crosslinking agent include compounds having two or more epoxy groups in the molecule. Examples of commercially available products include “Denacol” (registered trademark) series manufactured by Nagase Chemtech, diepoxy / polyepoxy compounds manufactured by Sakamoto Pharmaceutical Co., Ltd., and “EPICRON” (registered trademark) series manufactured by DIC.

Examples of the aziridine-based crosslinking agent include compounds having two or more aziridinyl groups in the molecule. Examples of the hydrazine-based crosslinking agent include hydrazine and compounds having two or more hydrazine groups (hydrazine skeleton) in the molecule.

Among these, a functional group possessed by polyurethane is preferably a hydroxyl group and / or a carboxyl group and / or a sulfonic acid group, and a cross-linking agent is preferably a polyisocyanate-based cross-linking agent or a carbodiimide compound. Moreover, the combined use of a carbodiimide compound and a polyisocyanate-based cross-linking agent can further increase the cross-linking structure of the polyurethane resin and enhance the moist heat resistance effect while maintaining flexibility.

Since water-dispersed polyurethane generally contains a hydrophilic group in its molecular structure, it has a high affinity with water molecules compared to conventional organic solvent-based polyurethanes, and it easily swells in a wet environment, and the molecular structure of polyurethane is Since it is easily relaxed, it tends to be difficult to maintain the high physical properties obtained during drying in a wet environment. On the other hand, by applying the above-mentioned crosslinking agent, the moist heat resistance effect can be enhanced and the tensile strength of the sheet when wet can be increased. As a result, it is possible to suppress structural changes of polyurethane molecules due to water in the dyeing process, etc., and to maintain the form stability as a sheet-like material and the adhesion between polyurethane and fibrous base material. A sense of quality can be achieved.

Since the carbodiimide crosslinking agent has excellent crosslinking reactivity even at a low temperature of 100 ° C. or lower, it is preferably used from the viewpoint of productivity. In addition, the isocyanate compound and / or the blocked isocyanate compound, in addition to mainly reacting with a hydroxyl group, in a high temperature region, particularly at a temperature of 120 ° C. to 200 ° C., preferably 140 ° C. to 200 ° C. Increased reactivity with urethane bonds and / or urea bonds constituting the segment (HS) part, forming allophanate bonds and burette bonds, giving a tougher cross-linked structure, and clarifying the micro phase separation structure of polyurethane be able to.

The storage elastic modulus E ′ at a temperature of 20 ° C. of the polyurethane film in the present invention is preferably 1 to 100 MPa, more preferably 2 to 50 MPa from the viewpoint of flexibility and impact resilience. Further, the loss elastic modulus is preferably 0.1 MPa to 20 MPa, and more preferably 0.5 MPa to 12 MPa. Further, tan δ is preferably 0.01 to 0.4, more preferably 0.02 to 0.35.

The storage elastic modulus E ′ and tan δ in the present invention were measured at a frequency of 12 Hz using a storage elastic modulus measuring apparatus [DMA7100 (manufactured by Hitachi High-Tech Science Co., Ltd.)] for a polyurethane film (film) having a film thickness of 200 μm. It is a measured value. tan δ is a numerical value represented by E ″ / E ′ (E ″ represents a loss elastic modulus).

E 'indicates the elastic properties of the polyurethane resin. If this E' is too small, the wrinkle recovery property of the sheet-like material becomes poor, and if it is too large, the texture of the sheet-like material becomes hard.

On the other hand, tan δ indicated by E ″ / E ′ (E ″ is a loss elastic modulus and indicates a viscous property) means a ratio of the viscous property based on the elastic property of polyurethane. If tan δ is too small, the wrinkle recovery property of the sheet-like material is poor as in E ′, and if it is too large, the texture of the sheet-like material becomes hard.

The density of the sheet-like material of the present invention is preferably 0.2 to 0.7 g / cm ³ . The density is more preferably 0.2 g / cm ³ or more, and still more preferably 0.25 g / cm ³ or more. By setting the density to 0.2 g / cm ³ or more, the surface appearance becomes dense and high-grade quality can be expressed. On the other hand, when the density of the sheet-like material is preferably 0.7 g / cm ³ or less, more preferably 0.6 g / cm ³ or less, the texture of the sheet-like material can be prevented from becoming hard.

The ratio of polyurethane contained in the sheet-like material of the present invention is preferably 10 to 80% by mass. By setting the ratio of polyurethane to 10% by mass or more, more preferably 15% by mass or more, it is possible to obtain sheet strength and to prevent the fibers from falling off. Further, by setting the ratio of polyurethane to 80% by mass or less, more preferably 70% by mass or less, it is possible to prevent the texture from becoming hard and to obtain a good napped quality.

The sheet-like material of the present invention is obtained by applying an elastic polymer such as water-dispersible polyurethane and coagulating a liquid in which a thickener is used in combination with an aqueous dispersion such as the water-dispersible polyurethane in water. By achieving a porous structure of the dispersion type polyurethane (elastic polymer), it is possible to obtain excellent crease recovery and flexibility that are very similar to artificial leather to which a solvent-based polyurethane is applied.

That is, the sheet-like material of the present invention is a sheet-like material obtained by applying a polymer elastic body having a hydrophilic group as a binder to a fibrous base material composed of ultrafine fibers and / or ultrafine fiber bundles. In the cross section obtained by cutting the sheet-like material in the thickness direction, among the polymer elastic bodies observed in the cut surface, the occupation ratio of the portion having a cross-sectional area of 50 μm ² or more independently is within the observation field. It is a sheet-like material characterized by being 0.1% or more and 5.0% or less with respect to the area.

Further, according to a preferred embodiment, there is provided a sheet-like material in which a polymeric elastic body having a hydrophilic group is provided as a binder to a fibrous base material composed of ultrafine fibers and / or ultrafine fiber bundles. In the cross section cut in the thickness direction of the product, a sheet-like product characterized in that 1% or more and 35% or less of the outer periphery of the cross section of the ultrafine fiber and / or ultrafine fiber bundle is covered with a polymer elastic film.

[Method for producing sheet-like material]
Next, the manufacturing method of the sheet-like material of this invention is demonstrated.

As the fibrous base material used in the present invention, as described above, fabrics such as woven fabrics, knitted fabrics and non-woven fabrics can be preferably employed. Especially, since the surface quality of the sheet-like thing at the time of surface raising treatment is favorable, a nonwoven fabric is used preferably. In the fibrous base material of the present invention, these woven fabrics, knitted fabrics, nonwoven fabrics and the like can be appropriately laminated and used together.

As the nonwoven fabric used in the present invention, either a short fiber nonwoven fabric or a long fiber nonwoven fabric may be used, but a short fiber nonwoven fabric is preferably used in that a surface quality consisting of a uniform raised length can be obtained.

The fiber length of the short fibers in the short fiber nonwoven fabric is preferably 25 mm to 90 mm, more preferably 35 mm to 75 mm. By setting the fiber length to 25 mm or more, a sheet-like material having excellent wear resistance can be obtained by entanglement. Further, by making the fiber length 90 mm or less, a sheet-like product having a higher quality can be obtained.

Examples of fibers constituting the fibrous base material include polyesters such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate and polylactic acid, polyamides such as 6-nylon and 66-nylon, acrylic, polyethylene, polypropylene, and thermoplastic cellulose. A fiber made of a thermoplastic resin that can be melt-spun such as can be used. Among these, polyester fibers are preferably used from the viewpoints of strength, dimensional stability, and light resistance. The fibrous base material may be configured by mixing fibers of different materials.

The cross-sectional shape of the fiber used in the present invention may be a round cross section, but may be a polygonal shape such as an ellipse, a flat shape, and a triangular shape, or an irregular cross section such as a sector shape and a cross shape.

The average fiber diameter of the fibers constituting the fibrous base material is preferably 0.1 to 7 μm, more preferably 0.3 to 5 μm. By making the average fiber diameter of the fibers 7 μm or less, the feel of the fibrous base material becomes more flexible. On the other hand, when the average fiber diameter of the fibers is 0.1 μm or more, the color developability after dyeing is further improved.

In the present invention, when the fibrous base material is a nonwoven fabric, the nonwoven fabric can be combined with a woven fabric or a knitted fabric for the purpose of improving the strength. The combination of a nonwoven fabric and a woven fabric or a knitted fabric can employ any method such as laminating the woven fabric or knitted fabric on the nonwoven fabric, or inserting the woven fabric or knitted fabric into the nonwoven fabric. Especially, it is a preferable aspect to use a textile fabric from a viewpoint which can expect form stability improvement and strength improvement.

The single yarn (warp and weft) constituting the woven fabric or knitted fabric may be a single yarn made of synthetic fiber such as polyester fiber or polyamide fiber. It is preferable that the yarn is made of fibers of the same material as the ultrafine fibers.

Examples of the form of such a single yarn include filament yarn and spun yarn, and these strong twisted yarns are preferably used. In addition, filament yarn is preferably used for the spun yarn because it causes surface fluff to fall off.

When using a strong twisted yarn, the number of twists is preferably 1000 T / m or more and 4000 T / m or less, more preferably 1500 T / m or more and 3500 T / m or less. If the number of twists is less than 1000 T / m, the number of single fibers constituting the strong twisted yarn by needle punching increases, and the physical properties of the product tend to deteriorate and the exposure of the single fibers to the product surface tends to increase. Moreover, when the number of twists is greater than 4000 T / m, the single fiber breakage is suppressed, but the strong twisted yarns constituting the woven fabric and the knitted fabric become too hard, and thus tend to cause hardening of the texture.

Further, in the present invention, it is a preferable aspect to use an ultrafine fiber expression type fiber as the fibrous base material. By using the ultrafine fiber expression type fiber for the fibrous base material, it is possible to stably obtain a form in which the bundle of ultrafine fibers described above is entangled.

When the fibrous base material is a non-woven fabric, the non-woven fabric preferably has a structure in which a bundle of ultrafine fibers (fiber bundle) is entangled. Since the ultrafine fibers are entangled in a bundle state, the strength of the sheet-like material is improved. The nonwoven fabric of such an embodiment can be obtained by causing the ultrafine fibers to develop after entanglement of the ultrafine fiber-expressing fibers in advance.

The ultra-fine fiber development type fiber is a sea-island type in which two component thermoplastic resins with different solvent solubility are used as a sea component and an island component, and the sea component is dissolved and removed using a solvent, etc. It is possible to employ a peelable composite fiber in which the composite fiber and the two-component thermoplastic resin are alternately arranged radially or in a multilayer shape on the fiber cross section, and each component is peeled and divided to divide the fiber into ultrafine fibers.

Among these, the sea-island type composite fiber can be preferably used also from the viewpoint of the flexibility and texture of the sheet-like material because it can provide an appropriate gap between the island components, that is, between the ultrafine fibers, by removing the sea component. .

For the sea-island type composite fiber, a sea-island type composite base is used, and the sea-island type composite fiber, in which two components of the sea component and the island component are mutually arranged and spun, and the two components of the sea component and the island component are mixed and spun. Although there are mixed spun fibers, sea-island type composite fibers are preferably used from the viewpoint that ultrafine fibers having a uniform fineness can be obtained and that a sufficiently long ultrafine fiber is obtained and contributes to the strength of the sheet-like material.

As the sea component of the sea-island composite fiber, polyethylene, polypropylene, polystyrene, copolymer polyester obtained by copolymerizing sodium sulfoisophthalic acid, polyethylene glycol, or the like, polylactic acid, polyvinyl alcohol, or the like can be used. Among these, copolymerizable polyesters, polylactic acid and hot water-soluble polyvinyl alcohol, which are copolymerizable with alkali-decomposable sodium sulfoisophthalic acid or polyethylene glycol, which can be decomposed without using an organic solvent, are preferably used.

As for the (ratio) ratio of the sea component to the island component of the sea-island type composite fiber, the mass ratio of the island fiber to the sea-island type composite fiber is preferably 0.2 to 0.9, more preferably 0.3 to 0.00. 8. By setting the mass ratio of the sea component and the island component to 0.2 or more, the removal rate of the sea component can be reduced, and the productivity is further improved. In addition, by setting the mass ratio to 0.9 or less, it is possible to improve the spreadability of the island fibers and prevent the island components from joining. The number of islands can be adjusted as appropriate according to the design of the base.

The major axis of a single fiber of an ultrafine fiber expression type fiber such as a sea-island type composite fiber is preferably 5 to 80 μm, more preferably 10 to 50 μm. If the long diameter of the single fiber is smaller than 5 μm, the strength of the fiber is weak, and there is a tendency that single fiber breakage increases due to the needle punching process described later. Moreover, when the long diameter of a single fiber becomes larger than 80 micrometers, efficient entanglement may not be performed by a needle punch process etc.

As a method of obtaining a nonwoven fabric as a fibrous base material used in the present invention, a method of entanglement of a fiber web by a needle punching process or a water jet punching process, a spunbond method, a melt blow method, a papermaking method, or the like is adopted. Can do. Among them, a method that undergoes a treatment such as a needle punching treatment or a water jet punching treatment is preferably used in order to obtain the state of the ultrafine fiber bundle as described above.

Further, in order to laminate and integrate the nonwoven fabric used as the fibrous base material with the woven fabric or the knitted fabric, needle punch processing, water jet punch processing or the like is preferably used from the viewpoint of fiber entanglement. Among them, needle punching is preferably used from the viewpoint that the fibers can be oriented in the vertical direction of the fibrous base material without being limited by the sheet thickness.

The needle used in the needle punching process preferably has 1 to 9 barbs. By making the number of barbs one or more, efficient fiber entanglement becomes possible. On the other hand, fiber damage can be suppressed by setting the number of barbs to 9 or less. When the number of barbs is more than 9, fiber damage increases, and needle marks may remain on the fibrous base material, resulting in poor appearance of the product.

In addition, when the nonwoven fabric and the woven fabric or knitted fabric are entangled and integrated, the nonwoven fabric is preliminarily entangled. This is a desirable mode for further prevention. As described above, when a method of providing preliminary entanglement in advance by needle punching is employed, it is effective to perform the punch density at 20 pieces / cm ² or more. The pre-entanglement is preferably given at a punch density of 100 / cm ² or more, and more preferably pre-entanglement is given at a punch density of 300 / cm ² to 1300 / cm ² .

With a punch density of less than 20 pre-entanglements / cm ² , the width of the nonwoven fabric leaves room for narrowing due to the needle punch process during and after entanglement with the woven fabric or knitted fabric. This is because wrinkles may occur in the woven fabric or knitted fabric with the change, and a smooth fibrous base material may not be obtained. Further, when the punch density of the preliminary entanglement is higher than 1300 / cm ² , generally the entanglement of the nonwoven fabric itself proceeds so much that the entanglement with the fibers constituting the woven fabric or the knitted fabric is sufficiently formed. This is because there is less room, which is disadvantageous for realizing a non-separated integrated structure in which the nonwoven fabric and the woven or knitted fabric are intertwined firmly.

In the present invention, regardless of the presence or absence of woven fabric or knitted fabric, when the fibers are entangled by the needle punching process, the punch density range is preferably 300 / cm ² to 6000 / cm ^2, and 1000 / It is a more preferable aspect to set it to cm ² to 3000 pieces / cm ² .

For entanglement of nonwoven fabric and woven fabric or knitted fabric, fabric or knitted fabric is laminated on one or both sides of the nonwoven fabric, or woven fabric or knitted fabric is sandwiched between multiple nonwoven fabrics, and fibers are entangled by needle punching. It can be a quality substrate.

In addition, when the water jet punching process is performed, it is a preferable aspect that water is performed in a columnar flow state. Specifically, water is preferably ejected from a nozzle having a diameter of 0.05 to 1.0 mm at a pressure of 1 to 60 MPa.

The apparent density of the nonwoven fabric composed of ultrafine fiber generating fibers after needle punching or water jet punching is preferably 0.13 to 0.45 g / cm ³ , more preferably 0.15 to 0.30 g / cm ³ . By setting the apparent density to 0.13 g / cm ³ or more, an artificial leather having sufficient form stability and dimensional stability can be obtained. On the other hand, when the apparent density is 0.45 g / cm ³ or less, a sufficient space for applying the polymer elastic body can be maintained.

The thickness of the fibrous base material is preferably 0.3 mm or more and 6.0 mm or less, and more preferably 1.0 mm or more and 3.0 mm or less. If the thickness of the fibrous base material is smaller than 0.3 mm, the form stability of the sheet-like material may be poor. On the other hand, when the thickness is larger than 6.0 mm, needle breakage tends to occur frequently in the needle punching process.

The nonwoven fabric composed of the ultrafine fiber-generating fibers thus obtained can be shrunk by dry heat or wet heat or both from the viewpoint of densification and further densified.

When sea-island type composite fibers are used, the sea removal treatment for removing the sea components of the fibers is performed before and / or after the application of the water-dispersed polyurethane dispersion containing the water-dispersed polyurethane to the fibrous base material. It can be carried out. When sea removal treatment is performed before application of the water-dispersed polyurethane dispersion, the polyurethane tends to be in direct contact with the ultrafine fibers, and the ultrafine fibers can be strongly held, so that the wear resistance of the sheet-like material is improved.

On the other hand, by applying an aqueous dispersion type polyurethane dispersion liquid after adding an inhibitor such as ultrafine fibers and cellulose derivatives or polyvinyl alcohol (hereinafter sometimes abbreviated as PVA) before applying the water dispersion type polyurethane dispersion liquid. In addition, the adhesion between the ultrafine fiber and the polyurethane resin can be lowered, and a softer texture can also be achieved.

The aforementioned inhibitor application can be performed either before or after the sea-sealing treatment of the sea-island structure fibers. By applying an inhibitor before the sea removal treatment, even when the fabric weight is lowered and the tensile strength of the sheet is lowered, the shape retention of the fibrous base material can be increased. For this reason, in addition to being able to process a thin sheet stably, the thickness retention of the fibrous base material in the sea removal treatment step can be increased, and densification of the fibrous base material can be suppressed. On the other hand, since the densification of the fibrous base material can be realized by applying the inhibitor after the sea removal treatment, it is preferable to appropriately adjust according to the purpose.

As the inhibitor, PVA is preferably used because it has a high reinforcing effect on the fibrous base material and is difficult to dissolve in water. Among PVA, it is difficult to elute an inhibitor at the time of applying a water-dispersed polyurethane dispersion, and it is possible to apply a high water saponification degree PVA, which is more difficult to water, from the viewpoint of being able to inhibit adhesion between ultrafine fibers and polyurethane. This is a more preferable embodiment.

The saponification degree of the high saponification degree PVA is preferably 95% or more and 100% or less, more preferably 98% or more and 100% or less. By setting the saponification degree to 95% or more, elution at the time of applying the water-dispersed polyurethane dispersion can be suppressed.

The polymerization degree of PVA is preferably 500 or more and 3500 or less, and more preferably 500 or more and 2000 or less. By setting the polymerization degree of PVA to 500 or more, elution of the high saponification degree PVA at the time of applying the polyurethane dispersion can be suppressed. Moreover, by setting the polymerization degree of PVA to 3500 or less, the viscosity of the high saponification degree PVA liquid does not become too high, and the high saponification degree PVA can be stably imparted to the fibrous base material.

The amount of PVA applied is preferably 0.1% by mass to 80% by mass with respect to the fibrous base material remaining in the product, and the amount applied is more preferably 5% by mass to 60% by mass. By applying 0.1% by mass or more of the high saponification degree PVA, it is possible to suppress the shape stability effect in the sea removal treatment process and the non-attachment property between the ultrafine fibers and the polyurethane. Moreover, by giving 80% by mass or less of the high saponification degree PVA, the adhesion between the ultrafine fibers and the polyurethane is not lowered too much, and the raised fibers become uniform and a product having a uniform surface quality can be finished.

As a method of applying the inhibitor to the fibrous base material, from the viewpoint that the inhibitor can be uniformly applied, the inhibitor is dissolved in water, impregnated into the fibrous base material, and dried by heating. Is preferably used. If the drying temperature is too low, drying time is required for a long time. If the temperature is too high, the inhibitor is completely insolubilized and cannot be dissolved and removed later. For this reason, it is preferable to dry at the temperature of 80 degreeC or more and 180 degrees C or less, More preferably, it is 110 degreeC or more and 160 degrees C or less. Moreover, it is preferable that drying time is 1 minute or more and 30 minutes or less from a viewpoint of workability.

Dissolving and removing the inhibitor is performed by immersing the fibrous base material to which the inhibitor is applied in steam having a temperature of 100 ° C. or higher and hot water having a temperature of 60 ° C. or higher and 100 ° C. or lower. It is a preferred embodiment to dissolve and remove by squeezing.

The sea removal treatment can be performed by immersing a fibrous base material containing sea-island type composite fibers in the liquid and squeezing it. As the solvent for dissolving the sea component, when the sea component is polyethylene, polypropylene and polystyrene, an organic solvent such as toluene or trichloroethylene is used. When the sea component is a copolyester or polylactic acid, a sodium hydroxide aqueous solution is used. When the sea component is polyvinyl alcohol, hot water can be used.

Next, the polyurethane used as the polymer elastic body in the present invention will be described.

When the polyurethane is dispersed in an aqueous medium as particles, from the viewpoint of dispersion stability of the polyurethane, it is preferable to use the above-mentioned hydrophilic group-containing active hydrogen component as a constituent component of the polyurethane, and it is more preferable to use a neutralized salt. It is.

Examples of the neutralizing agent used in the neutralized salt of the compound having a hydrophilic group and active hydrogen include trimethylamine, triethylamine, amine compounds of triethanolamine, hydroxides such as sodium hydroxide and potassium hydroxide, and the like. It is done.

The addition time of the neutralizing agent used for the hydrophilic group-containing active hydrogen component is not particularly specified before and after the polyurethane polymerization step or before and after the dispersion step in an aqueous medium, but from the viewpoint of stability in the aqueous dispersion of polyurethane, It is preferably added before the dispersion step in the aqueous medium or during the dispersion step in the aqueous medium.

The content of the hydrophilic group-containing active hydrogen component and / or salt thereof based on the mass of the polyurethane is preferably 0.005 to 30% by mass, more preferably from the viewpoint of dispersion stability and water resistance of the polyurethane. 0.01 to 15% by mass.

When the polyurethane is dispersed in the aqueous medium as particles, in addition to using the hydrophilic group-containing active hydrogen component, the polyurethane can be dispersed in the aqueous medium using a surfactant as an external emulsifier of the polyurethane.

Examples of such surfactants include nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants. Surfactant may be used independently and can also use 2 or more types together.

Nonionic surfactants include polyoxyethylene nonyl phenyl ether, polyoxyethylene dinonyl phenyl ether, polyoxyethylene laurel ether, polyoxyethylene stearyl ether and other alkylene oxide addition types, and glycerin monostearate and other polyhydric alcohols. Examples include molds.

Examples of the anionic surfactant include sodium laurate, sodium laurel sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium salt of higher alcohol phosphate diester, sulfate ester salt, sulfonate salt, and phosphate ester Salt.

Examples of the cationic surfactant include quaternary ammonium salts such as distearyldimethylammonium chloride. Examples of amphoteric surfactants include methyl laurylaminopropionate, lauryldimethylbetaine, and palm oil fatty acid amidopropyldimethylaminoacetic acid betaine.

A conventional polyurethane dispersion manufacturing method can be applied to the polyurethane dispersion used in the present invention. For example, a method of emulsifying a liquid polymer obtained by reacting the aforementioned polyisocyanate, polyol, chain extender and / or hydrophilic group-containing polyol in water in the presence of an emulsifier, the aforementioned polyisocyanate, polyol and / or When a prepolymer having an isocyanate group at the molecular end reacted with a chain extender and / or a hydrophilic group-containing polyol is prepared, and the prepolymer is emulsified in water in the presence of an emulsifier, the chain extender is used at the same time or later. Examples thereof include a method of completing the elongation reaction and a method of emulsifying in water as it is without using an emulsifier after reacting the aforementioned polyisocyanate, polyol and / or chain extender and / or hydrophilic group-containing polyol. When polymerizing without forming the prepolymer and when polymerizing the prepolymer, the polymerization may be performed in the absence of a solvent or in an organic solvent such as methyl ethyl ketone, toluene, and acetone.

The polyurethane is applied to the fibrous base material by, for example, immersing the aqueous dispersed polyurethane dispersion containing the synthesized water-dispersible polyurethane in the fibrous base material, and then coagulated and solidified by heating and drying. .

In the present invention, the water-dispersed polyurethane dispersion added with the above-mentioned thickener is applied to the fibrous base material, and the heat is preferably 50 ° C. to 100 ° C., more preferably 60 ° C. to 97 ° C. A porous structure of polyurethane can be achieved by coagulating water-dispersed polyurethane in water.

The immersion time in hot water is preferably from 10 seconds to 5 minutes, more preferably from 30 seconds to 3 minutes. By setting the immersion time in this way, the polyurethane can be sufficiently solidified.

Thus, by setting the polyurethane coagulation method to hydrothermal coagulation, the amount of heat per hour required for polyurethane increases, so the coagulation rate increases and the bias of the water-dispersed polyurethane dispersion to the fibrous base material decreases. Therefore, the adhesion between the fiber and the polyurethane is reduced, and the texture is softened.

Furthermore, by using a thickener together with the water-dispersed polyurethane dispersion, the polyurethane emulsion in the water-dispersed polyurethane dispersion impregnated in the fibrous base material is affected by the viscosity of the liquid, and the Brownian motion of the emulsion Is suppressed. Therefore, the number of times of contact between emulsions is reduced, the polyurethane lump at the time of coagulation can be reduced, and a soft texture can be achieved. In addition, the dispersion does not diffuse into the hot water, so that the dropping of the polyurethane during the coagulation step can be suppressed, and a coagulation process with excellent productivity can be achieved.

When a dispersion using a thickener in combination with an aqueous dispersion such as water-dispersed polyurethane is coagulated in hot water, the coating film of the water-dispersed polyurethane (elastic polymer) becomes small and a soft texture is obtained. Furthermore, the polyurethane film covering the fibrous base material is reduced, and a soft texture is obtained.

As the thickener added to the water-dispersed polyurethane dispersion, nonionic, anionic, cationic and amphoteric thickeners can be applied. Among these, nonionic thickeners are preferably used.

The type of thickener can be selected from associative thickeners and water-soluble polymer thickeners. As the associative thickener, associative thickeners known for urethane-modified compounds, acrylic-modified compounds and their copolymer compounds can be applied. For example, JP 2003-292937 A, JP 2001-254068 A, JP 60-49022 A, JP 2008-231421 A, JP 2002-069430 A, and JP 9-71766 A. Urethane-based associative thickeners described in JP-A No. 62-292879, and urethane monomers and other acrylic monomers described in JP-A Nos. 62-292879 and 10-112030. Examples include associative thickeners obtained by polymerization.

Examples of water-soluble polymer compounds include natural polymer compounds, semi-synthetic polymer compounds, and synthetic polymer compounds.

Non-natural compounds such as tamarind gum, guar gum, roast bean gum, tragacanth gum, starch, dextrin, gelatin, agarose, casein and curdlan, xanthan gum, carrageenan, gum arabic, pectin, collagen, chondroitin Examples include anionic compounds such as sodium sulfate, sodium hyaluronate, carboxymethyl starch, and phosphate starch, and cationic compounds such as cationic starch and chitosan.

Semi-synthetic polymer compounds include nonionic compounds such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxyethyl cellulose, methyl hydroxypropyl cellulose, soluble starch and methyl starch, and anionic compounds such as carboxymethyl cellulose, carboxymethyl starch and alginate The compound of this is mentioned.

Synthetic polymer compounds include nonionic compounds such as polyvinyl alcohol, polyacrylamide, polyvinyl pyrrolidone, polymethyl vinyl ether, polyethylene glycol and polyisopropyl acrylamide, carboxyvinyl polymer, sodium polyacrylate and sodium polystyrene sulfonate. And anionic compounds such as dimethylaminoethyl (meth) acrylate quaternary salt, dimethyldiallylammonium chloride, polyamidine, polyvinylimidazoline, and polyethyleneimine.

In the present invention, as the thickener, it is preferable to apply a nonionic thickener that hardly affects the stability of the water-dispersed polyurethane dispersion.

Moreover, it is preferable that the water-dispersed polyurethane dispersion added with a thickener exhibits non-Newtonian properties. If the water-dispersed polyurethane dispersion is non-Newtonian and its viscosity is lowered by applying force, the viscosity is lowered by applying force by stirring or the like. In addition, after the impregnation, the viscosity returns to its original value by leaving it stationary, so that the dispersion impregnated in the fibrous base material is less likely to fall off the fibrous base material. .

Further, it is more preferable that the water-dispersed polyurethane dispersion added with the thickener exhibits thixotropic properties. If the water-dispersed polyurethane dispersion is thixotropic, the viscosity can be lowered by applying force by stirring or the like, and the dispersion can be uniformly impregnated into the fibrous base material. By leaving it at rest, the viscosity returns to the original, so that the dispersion liquid impregnated in the fibrous base material is less likely to fall off from the fibrous base material.

The thickener exhibiting thixotropy can be appropriately selected from the above-mentioned thickeners. Natural polymer compounds (polysaccharides) that are expected to have a large thickening effect with a small addition amount are preferably used. As the thickener, guar gum is more preferable because it is excellent in water solubility, excellent in compatibility with water-dispersed polyurethane liquid, and has high thixotropic properties at low concentrations.

The viscosity of the aqueous resin dispersion containing a thickener is preferably 200 mPa · s to 100,000 mPa · s, more preferably 200 mPa · s to 10,000 mPa · s, and still more preferably 200 mPa · s to 5000 mPa · s. is there. By setting the viscosity of the aqueous resin dispersion to 200 mPa · s or more, dropping of polyurethane in the hot water coagulation step can be suppressed, and by setting the viscosity to 100000 mPa · s or less, the water dispersion type The polyurethane dispersion can be uniformly impregnated into the fibrous base material.

The water-dispersed polyurethane dispersion applied to the fibrous base material contains a heat-sensitive coagulant from the viewpoint that the migration of polyurethane during polyurethane coagulation can be suppressed and the fibrous base material can be uniformly impregnated with polyurethane. It is preferable.

Examples of the heat-sensitive coagulant include inorganic salts such as sodium sulfate, magnesium sulfate, calcium sulfate, calcium chloride, magnesium chloride and calcium chloride, and ammonium salts such as sodium persulfate, potassium persulfate, ammonium persulfate and ammonium sulfate. After adjusting the coagulation temperature of the water-dispersed polyurethane by adjusting the addition amount as appropriate, either alone or in combination of two or more, the water-dispersed polyurethane dispersion is heated and destabilized to solidify. be able to.

The heat-sensitive coagulation temperature of the water-dispersed polyurethane dispersion is preferably 40 to 90 ° C., more preferably 50 to 80 ° C., from the viewpoint of storage stability and texture of the processed fiber product.

In addition to the above-mentioned crosslinking agent and heat-sensitive coagulant, the following various additives can be further added to the polyurethane dispersion.

For example, pigments such as carbon black, antioxidants (hindered phenol-based and sulfur-based, phosphorus-based antioxidants), ultraviolet absorbers (benzotriazole-based, triazine-based, benzophenone-based and benzoate-based ultraviolet absorbers, etc.) ), Weathering stabilizers such as hindered amine light stabilizers, soft water repellents (soft water repellents such as polysiloxanes, silicone compounds such as modified silicone oils, and fluorine compounds such as fluoroalkyl ester polymers of acrylic acid) , Wetting agents (wetting agents such as ethylene glycol, diethylene glycol, propylene glycol and glycerin), antifoaming agents (foaming agents such as octyl alcohol, sorbitan monooleate, polydimethylsiloxane, polyether-modified silicone and fluorine-modified silicone), filling Agent (carbonic acid cal , Titanium oxide, silica, talc, ceramics, fine particles such as resin, and fillers such as hollow beads), flame retardants (halogen, phosphorus, antimony, melamine, guanidine, guanylurea, silicone, Inorganic flame retardant), microballoon (eg: Matsumoto Yushi: “Matsumoto Microsphere” (registered trademark)), foaming agent [eg, dinitrosopentamethylenetetramine (eg, “Cermic A” manufactured by Sankyo Kasei) Registered trademark)), azodicarbonamide (example: “Cermic CAP” ＡＰ (registered trademark) manufactured by Sankyo Kasei), p, p′-oxybisbenzenesulfonylhydrazide (example: “Cermic S” (registered trademark) manufactured by Sankyo Chemical) ), N, N′-dinitrosopentamethylenetetramine (eg, “Cellular GX” (registered trademark) manufactured by Eiwa Kasei), etc. Foaming agents and inorganic foaming agents such as sodium hydrogen carbonate (eg “Cermic 266” (registered trademark) manufactured by Sankyo Kasei) and the like], 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) Propionamide] (Example: “VA-086” manufactured by Wako Pure Chemical Industries, Ltd.), viscosity modifier, plasticizer (phthalate ester, adipic acid ester, etc.), and mold release agent (wax, metal soap, and mixtures thereof) Additives such as system release agents and the like may be included.

After impregnating the fiber-dispersed polyurethane dispersion into a fibrous base material and solidifying it, additional heating (in order to promote fusion of the water-dispersed polyurethane emulsion, optimize the molecular structure of the polyurethane, and improve the heat and moisture resistance ( Curing) is a preferred mode. Cure can be performed continuously with the step of solidifying the fibrous base material after impregnating the water-dispersed polyurethane dispersion, and the fibrous base material is impregnated with the water-dispersed polyurethane dispersion and solidified. Later, it can also be carried out in a separate process.

When the temperature is too low, the drying time is required for a long time, and when the temperature is too high, the thermal decomposition of polyurethane is promoted. Therefore, it is preferable to dry at a temperature of 80 ° C. or higher and 200 ° C. or lower, more preferably It is 120 degreeC or more and 190 degrees C or less, More preferably, they are 150 degreeC or more and 180 degrees C or less.

Furthermore, the drying time is preferably 1 minute or more and 60 minutes or less, more preferably 1 minute or more and 30 minutes or less from the viewpoint of workability. In the present invention, by treating the curing temperature at a high temperature for a short time, the fluidity of the polyurethane molecules is increased, and the hard segment (HS) portion formed mainly from urethane groups and urea groups and mainly formed from polyols. In the molecular structure composed of the soft segment (SS) portion, the aggregation of the HS portion can be further enhanced, the microphase separation structure of the HS and SS portion can be clarified, and the heat and moisture resistance can be improved.

After the polyurethane is applied, dividing the obtained sheet-like material provided with the polyurethane into half or several sheets in the sheet thickness direction is excellent in production efficiency and is a preferable embodiment.

Before the raising treatment described later, a lubricant such as a silicone emulsion can be applied to the polyurethane-applied sheet. In addition, applying an antistatic agent before the raising treatment is a preferable mode in order to make it difficult for the grinding powder generated from the sheet-like material to be deposited on the sandpaper by grinding.

In order to form napping on the surface of the sheet-like material, raising treatment can be performed. The raising treatment can be performed by a method of grinding using sandpaper, roll sander or the like.

If the thickness of the sheet material is too thin, physical properties such as tensile strength and tear strength of the sheet material will be weak, and if it is too thick, the texture of the sheet material will be hard. Preferably there is.

The sheet-like material can be dyed. As a dyeing method, it is preferable to use a liquid dyeing machine because the sheet-like material can be softened by dyeing the sheet-like material and at the same time giving a stagnation effect. If the dyeing temperature is too high, the polyurethane may be deteriorated. Conversely, if the dyeing temperature is too low, dyeing of the dye onto the fiber becomes insufficient, and therefore the dyeing temperature can be set depending on the type of the fiber. In general, the dyeing temperature is preferably 80 ° C. or higher and 150 ° C. or lower, more preferably 110 ° C. or higher and 130 ° C. or lower.

The dye used is selected according to the type of fiber constituting the fibrous base material. For example, disperse dyes can be used for polyester fibers, acidic dyes or metal-containing dyes can be used for polyamide fibers, and combinations thereof can be used. When the sheet-like material is dyed with a disperse dye, reduction washing can be performed after dyeing.

In addition, it is also a preferable aspect to use a dyeing assistant during dyeing. By using a dyeing assistant, the uniformity and reproducibility of dyeing can be improved. In addition, a finishing treatment using a softening agent such as silicone, an antistatic agent, a water repellent, a flame retardant, a light proofing agent, and an antibacterial agent can be performed in the same bath or after dyeing.

The sheet-like material obtained by the present invention is mainly used as artificial leather, for example, as a skin material for furniture, chairs and wall materials, and seats, ceilings and interiors in vehicles such as automobiles, trains and aircraft. Interior materials with elegant appearance, shirts, jackets, casual shoes, sports shoes, upper shoes for men's shoes and women's shoes, trims, bags, belts, wallets, etc., and clothing materials used for some of them It can be suitably used as industrial materials such as wiping cloth, polishing cloth and CD curtain.

Next, the sheet-like material of the present invention and the manufacturing method thereof will be described in more detail by way of examples, but the present invention is not limited to these examples.

[Evaluation methods]
(1) Dropping rate during solidification of polyurethane:
The mass of the fibrous base material and the mass after impregnating the fibrous base material with the water-dispersed polyurethane dispersion were measured, and the polyurethane solid content contained in the difference was defined as the polyurethane adhesion amount A. Next, the fibrous base material impregnated with the water-dispersed polyurethane dispersion was coagulated with hot water or steam, and the mass after drying was measured. The difference from the fibrous base material was defined as polyurethane adhesion amount B. . The polyurethane drop-off rate at the time of coagulation was calculated by the following formula and evaluated by the average of the results of 10 points measurement.
Polyurethane drop-off rate (%) = Polyurethane adhesion amount B / Polyurethane adhesion amount × 100.

(2) Viscosity measurement of water-dispersed polyurethane dispersion:
The viscosity of the prepared water-dispersed polyurethane dispersion was measured using a rotational viscometer (B-type viscometer: Tokyo Keiki Seisakusho) under an atmosphere at a temperature of 25 ° C. and a rotational speed condition of 0.5 rpm. The measurement was performed under a rotation speed condition of rotation / min.

(3) Appearance quality of sheet-like material:
The appearance quality of the sheet-like material was evaluated on the basis of visual and sensory evaluations in the following five stages, with 10 healthy adult males and 10 adult females each, with a total of 20 evaluators. It was. Appearance quality was rated as 4th to 5th grades.
Grade 5: There is uniform fiber napping, the fiber dispersion state is good, and the appearance is good.
Grade 4: Evaluation between grade 5 and grade 3.
Third grade: The dispersion state of the fibers is somewhat poor, but there are fiber nappings and the appearance is reasonably good.
Second grade: An evaluation between the third grade and the first grade.
First grade: Overall, the fiber dispersion is very poor and the appearance is poor.

(4) Texture of sheet:
The texture of the sheet is evaluated by the following three sensory evaluations using tactile sensation, with 10 healthy adult males and 10 adult females each. It was a good evaluation. The texture was good (excellent rubber elasticity).
(Double-circle): It is softer than the artificial leather which applied the organic solvent type polyurethane of the same basis weight, and is excellent in crease wrinkle recovery.
○: The same softness and crease recovery properties as artificial leather using organic solvent-based polyurethane with the same basis weight.
X: The sheet is hard and has a paper-like feel.

(5) Calculation method of occupancy ratio of non-porous lumps of 50 μm ² or more (parameter A):
Developed by the US National Institutes of Health for 10 SEM images of a cross section cut in the thickness direction of the artificial leather in the length direction or width direction of the artificial leather at a magnification of 500 times with a scanning electron microscope (SEM). A mass of 50 μm ² or more of the polyurethane cross section observed on the cut surface by ImageJ (version: 1.44p) of the image analysis software is an artificial leather in the observation field (4.3 × 10 ⁴ μm ² ) of the SEM image area. The ratio with respect to the area of a cross section was computed, and it evaluated by the average value of the numerical value of the total 10 images computed. FIG. 3 shows a schematic diagram of the parameter A calculation method. FIG. 3 is a schematic view showing a polyurethane lump 1 of parameter A, and is a diagram illustrating a polyurethane cross-section (not including the back part of the cross-section) in which the artificial leather is observed in the cross-section with the polyurethane lump 1. is there.

(6) Calculation method of polymer elastic body coverage ratio of ultrafine fiber cross section (parameter B):
Developed by the US National Institutes of Health for 10 SEM images of a cross section cut in the thickness direction of the artificial leather in the length direction or width direction of the artificial leather at a magnification of 500 times with a scanning electron microscope (SEM). 5 microfiber bundles observed with the image analysis software ImageJ (version: 1.44p) being cut perpendicular to the length direction of the fibers, the thickness is 1 μm or more in the outer circumference. The ratio of the portion in contact with the resin film was calculated. Evaluation was made based on the average value of the polymer elastic body covering ratios of a total of 50 ultrafine fiber cross-sections of the calculated 5 × 10 images. FIG. 4 shows a schematic diagram of the parameter B calculation method. FIG. 4 is a schematic diagram showing the outer periphery 2 of the ultrafine fiber and / or ultrafine fiber bundle of parameter B and the outer periphery 3 covered with the polymer elastic film, and the solid line portion indicates the outer periphery 2 of the ultrafine fiber bundle and the dotted line portion. These are the figures explaining the outer periphery 3 covered with the polymeric elastic body membrane | film | coat.

[Preparation of polyurethane liquid A]
Polycarbonate diol with Mn of 2,000 [“Duranol” (registered trademark) T5652 ”manufactured by Asahi Kasei Chemicals Co., Ltd.] as the polyol, MDI as the isocyanate, and 2,2-dimethylolpropionic acid as the intramolecular hydrophilic group After preparing a prepolymer in a toluene solvent, ethylene glycol and ethylenediamine as chain extenders and polyoxyethylene nonylphenyl ether and water as external emulsifiers are added and stirred, and then toluene is removed by decompression to remove water. A dispersion type polyurethane dispersion A was obtained.

[Preparation of polyurethane liquid B]
Polycarbonate diol with Mn of 2,000 [“Duranol” (registered trademark) T6002 ”manufactured by Asahi Kasei Chemicals Co., Ltd.] as the polyol, IPDI as the isocyanate, a diol compound having polyethylene glycol in the side chain as an intramolecular hydrophilic group, and A 2,2-dimethylolpropionic acid is used to prepare a prepolymer in an acetone solvent, and then ethylene glycol, ethylenediamine and water are added as chain extenders and stirred, and then the acetone is removed under reduced pressure to remove water. A dispersion type polyurethane dispersion B was obtained.

[Preparation of polyurethane liquid C]
Polycarbonate diol with Mn of 2,000 [“Duranol” (registered trademark) T5652 ”manufactured by Asahi Kasei Chemicals Co., Ltd.] as the polyol, IPDI as the isocyanate, trimethylolpropane as the intramolecular hydrophilic group, in a methyl ethyl ketone solvent After preparing the prepolymer, ethylene glycol and ethylenediamine as chain extenders, polyoxyethylene nonylphenyl ether and water as external emulsifiers are added and stirred, and then methyl ethyl ketone is removed by decompression to remove water dispersion type polyurethane dispersion D was obtained.

[Example 1]
As the sea component, polyethylene terephthalate copolymerized with 8 mol% of sodium 5-sulfoisophthalate is used, and as the island component, polyethylene terephthalate is used. The sea component is 20% by mass and the island component is 80% by mass. A sea-island type composite fiber having several 16 islands / 1 filament and an average fiber diameter of 20 μm was obtained. The obtained sea-island type composite fiber was cut into a fiber length of 51 mm to form a staple, a fiber web was formed through a card and a cross wrapper, and a nonwoven fabric was formed by needle punching.

The nonwoven fabric obtained in this manner was immersed in hot water at a temperature of 97 ° C. for 2 minutes to shrink and dried at a temperature of 100 ° C. for 5 minutes. Next, an active ingredient of an associative thickener [“Sickner 627N” manufactured by San Nopco Co., Ltd.] is added to the water-dispersible polyurethane dispersion A having a polyurethane solid content concentration of 20%. After impregnating a dispersion containing 4% by mass of magnesium sulfate and 1.2% by mass of magnesium sulfate with respect to the solid content of polyurethane, treated in hot water at a temperature of 95 ° C. for 1 minute, and then dried in hot air at a drying temperature of 100 ° C. for 15 minutes, Further, the obtained sheet was further heated at a temperature of 160 ° C. for 20 minutes.
A sheet provided with water-dispersed polyurethane was obtained so that the polyurethane mass relative to the island component mass of the nonwoven fabric was 35 mass%. There was almost no dropping of the polyurethane at 0.1% during the hot water coagulation of the polyurethane.

Next, the sheet thus obtained was immersed in a 10 g / L sodium hydroxide aqueous solution heated to a temperature of 95 ° C. and treated for 25 minutes to remove the sea components of the sea-island composite fibers. I got a sea sheet. The average monofilament diameter of the monofilament on the surface of the obtained sea removal sheet was 4.2 μm. Then, using a half-cutting machine having an endless band knife, the sea removal sheet is cut in half in the direction perpendicular to the thickness direction, and the non-half-cut side is ground using 120 mesh and 240 mesh sandpaper, Treated. Then, using a circular dyeing machine, it was dyed with a disperse dye and subjected to reduction washing to obtain an artificial leather having a basis weight of 221 g / m ² . The appearance quality of the obtained artificial leather was good, and the texture was good with no paper-like feeling. Parameter A was 4.0% and parameter B was 27.1%.

[Example 2]
The water-dispersed polyurethane dispersion A having a solid content adjusted to 20% is associated with an active ingredient of an epoxy-based crosslinking agent [“CR-5L” manufactured by DIC Corporation] in an amount of 5% by mass relative to the polyurethane solid content. Example 4 A dispersion in which an active ingredient of a type thickener [Sickner 627N manufactured by San Nopco Co., Ltd.] was added in an amount of 4% by mass with respect to the polyurethane solid content and 1.2% by mass of magnesium sulfate with respect to the polyurethane solid content An artificial leather having a basis weight of 223 g / m ² was obtained in the same manner as in Example 1 except that the same nonwoven fabric as 1 was impregnated. When the water-dispersed polyurethane was coagulated with hot water, the polyurethane did not fall off at 0.1%. The appearance quality of the obtained artificial leather was good, and the texture was good with no paper-like feeling. Parameter A was 4.1% and parameter B was 25.4%.

[Example 3]
As the sea component, polyethylene terephthalate copolymerized with 8 mol% of sodium 5-sulfoisophthalate is used, and as the island component, polyethylene terephthalate is used. The sea component is 20% by mass, and the island component is 80% by mass. A sea-island type composite fiber having 16 islands / 1 filament and an average fiber diameter of 20 μm was obtained. The obtained sea-island type composite fiber was cut into a fiber length of 51 mm to form a staple, a fiber web was formed through a card and a cross wrapper, and a nonwoven fabric was formed by needle punching.

The nonwoven fabric thus obtained was immersed in hot water at a temperature of 97 ° C. for 5 minutes to shrink and dried at a temperature of 100 ° C. for 10 minutes. Next, an aqueous solution in which PVA having a degree of saponification of 99% and a degree of polymerization of 1400 [“NM-14” manufactured by Nippon Synthetic Chemical Co., Ltd.] was adjusted to an aqueous solution having a solid content of 10% by mass was applied to the obtained nonwoven fabric. After drying at a temperature of 100 ° C. for 10 minutes, additional heating was performed at a temperature of 150 ° C. for 20 minutes to obtain a sheet. Next, the sheet thus obtained was immersed in a 100 g / L sodium hydroxide aqueous solution heated to a temperature of 50 ° C. and treated for 20 minutes to remove the sea components of the sea-island composite fibers. I got a sea sheet. The average fiber diameter of single fibers on the surface of the obtained sea removal sheet was 4.2 μm. Thereafter, the seawater-removed sheet was impregnated with water-dispersed polyurethane dispersion A prepared in the same manner as in Example 2, treated in hot water at a temperature of 95 ° C. for 1 minute, and then dried in hot air at a drying temperature of 100 ° C. for 15 minutes. A sheet provided with water-dispersed polyurethane was obtained so that the polyurethane mass relative to the island component mass of the nonwoven fabric was 35 mass%. The sheet provided with the water-dispersible polyurethane was immersed in hot water at a temperature of 98 ° C. for 10 minutes to remove the applied PVA, and then dried at a temperature of 100 ° C. for 10 minutes. Thereafter, the obtained sheet was further heated at a temperature of 160 ° C. for 20 minutes.

Then, using a half-cutting machine with an endless band knife, the sea removal sheet is cut in half perpendicular to the thickness direction, and the non-half cut side is ground using 120 mesh and 240 mesh sandpaper, and raised. Then, it was dyed with a disperse dye using a circular dyeing machine and subjected to reduction washing to obtain an artificial leather having a basis weight of 230 g / m ² . When the water-dispersed polyurethane was coagulated with hot water, the polyurethane did not fall off at 0.2%. The appearance quality of the obtained artificial leather was good, and the texture was good with no paper-like feeling. Parameter A was 3.8% and parameter B was 20.3%.

[Example 4]
3% by mass of the active ingredient of the associative thickener [Sannoco Co., Ltd. “Thickner 623N”] is added to the water-dispersed polyurethane dispersion B adjusted to a solid content concentration of 20% relative to the polyurethane solid content. An artificial leather having a basis weight of 218 g / m ² was obtained in the same manner as in Example 1, except that the same nonwoven fabric as in Example 1 was impregnated with the dispersion.

The drop-out of polyurethane during hot water coagulation of water-dispersed polyurethane was almost 0.1%. The appearance quality of the obtained artificial leather was good, and the texture was good with no paper-like feeling. Parameter A was 4.0% and parameter B was 26.8%.

[Example 5]
In the water-dispersed polyurethane dispersion B having a solid content adjusted to 20%, an active component of aqueous isocyanate [“Desmodur (registered trademark) N3900” manufactured by Bayer MaterialScience) is added to the polyurethane solid content. 3% by mass by weight, carbodiimide-based cross-linking agent [“Carbodilite” (registered trademark) V-02-L2 ”manufactured by Nisshinbo Chemicals Co., Ltd.) 3% by mass with respect to polyurethane solid content, and associative thickening Example 1 except that the same non-woven fabric as Example 1 was impregnated with a dispersion obtained by adding 3% by mass of the active ingredient of the agent [Sannoco Co., Ltd. “Thickner 623N”] to the polyurethane solid content. An artificial leather having a basis weight of 220 g / m ² was obtained.

The drop-out of polyurethane during hot water coagulation of water-dispersed polyurethane was almost 0.2%. The appearance quality of the obtained artificial leather was good, and the texture was good with no paper-like feeling. Parameter A was 4.3% and parameter B was 30.3%.

[Example 6]
In the water-dispersed polyurethane dispersion B having a solid content adjusted to 20%, an active component of aqueous isocyanate [“Desmodur (registered trademark) N3900” manufactured by Bayer MaterialScience) is added to the polyurethane solid content. 3% by mass by weight, carbodiimide-based cross-linking agent [“Carbodilite” (registered trademark) V-02-L2 ”manufactured by Nisshinbo Chemicals Co., Ltd.) 3% by mass with respect to polyurethane solid content, and associative thickening Example 3 except that the same non-woven fabric as Example 3 was impregnated with a dispersion liquid in which 3% by mass of an active ingredient of the agent [Sannopco Co., Ltd. “Thickener 623N”] was added to the polyurethane solid content. An artificial leather having a basis weight of 220 g / m ² was obtained.

The drop-off of polyurethane during hot water coagulation of water-dispersed polyurethane was almost 0.2%. The appearance quality of the obtained artificial leather was good, and the texture was good with no paper-like feeling. Parameter A was 4.2% and parameter B was 20.4%.

[Example 7]
Using the sea-island composite fiber of Example 1, a fiber web was formed through a card and a cross wrapper, and the resulting fiber web was laminated. After that, the twisted yarn was composed of 84 dtex-72 filaments with a weaving density of 96 per inch. After a woven fabric of x76 (longitudinal x weft) was superimposed on the front and back of the laminated fiber web, a laminated nonwoven fabric was formed by needle punching, and the polyurethane mass relative to the island component mass of the nonwoven fabric was 28 mass%. Water-dispersed polyurethane was applied to the sheet, and the sea removal sheet was cut in half perpendicular to the thickness direction using a half-cutting machine having an endless band knife, and the half-cut side was used with 120-mesh and 240-mesh sandpaper by grinding Te, except that subjected to raising treatment, in the same manner as in example 6, having a basis weight of 393 g / m ² artificial To give the leather. When the water-dispersed polyurethane was coagulated with hot water, the polyurethane did not fall off at 0.2%. The appearance quality of the obtained artificial leather was good, and the texture was good with no paper-like feeling. Parameter A was 3.6% and parameter B was 20.1%.

[Example 8]
In the water-dispersed polyurethane dispersion A adjusted to a solid content concentration of 20%, an active ingredient of aqueous isocyanate [“Desmodur (registered trademark) N3900” manufactured by Bayer MaterialScience Co., Ltd.]] is compared with polyurethane solid content. 3% by mass, 3% by mass of an active ingredient of a carbodiimide-based cross-linking agent [“Carbodilite” (registered trademark) V-02-L2 ”manufactured by Nisshinbo Chemicals Co., Ltd.) relative to the solid content of polyurethane, The same dispersion as in Example 3 was prepared by adding 2% by mass of an active ingredient of “Neosoft G” manufactured by Taiyo Kagaku Co., Ltd. to the polyurethane solid content and 1.2% by mass of magnesium sulfate relative to the polyurethane solid content. Except that it was impregnated into a nonwoven fabric and treated in hot water at a temperature of 95 ° C. for 3 minutes after impregnation with a polyurethane dispersion, the same as in Example 3. Basis weight was obtained artificial leather 221 g / ^{m 2.}

The drop-out of polyurethane during hot water coagulation of water-dispersed polyurethane was almost 0.1%. In addition, the half-cut surface of the half-cutting machine had no polyurethane unevenness, and the fibrous base material was impregnated with uniform polyurethane. The appearance quality of the obtained artificial leather was good, and the texture was good with no paper-like feeling. Parameter A was 3.3% and parameter B was 18.9%.

[Example 9]
Using the sea-island composite fiber of Example 1, a fiber web was formed through a card and a cross wrapper, and the resulting fiber web was laminated. After that, the twisted yarn was composed of 84 dtex-72 filaments with a weaving density of 96 per inch. After a woven fabric of x76 (longitudinal x weft) was superimposed on the front and back of the laminated fiber web, a laminated nonwoven fabric was formed by needle punching, and the polyurethane mass relative to the island component mass of the nonwoven fabric was 28 mass%. Water-dispersed polyurethane was applied to the sheet, and the sea removal sheet was cut in half perpendicular to the thickness direction using a half-cutting machine having an endless band knife, and the half-cut side was used with 120-mesh and 240-mesh sandpaper by grinding Te, except that subjected to raising treatment, in the same manner as in example 8, basis weight of 390 g / m ² artificial To give the leather. When the water-dispersed polyurethane was coagulated with hot water, the polyurethane did not fall off at 0.1%. In addition, the half-cut surface of the half-cutting machine had no polyurethane unevenness, and the fibrous base material was impregnated with uniform polyurethane. The appearance quality of the obtained artificial leather was good, and the texture was good with no paper-like feeling. Parameter A was 2.9% and parameter B was 19.2%.

[Example 10]
Except that the non-woven fabric was not applied with PVA with a degree of saponification of 99% and a degree of polymerization of 1400 [“NM-14” manufactured by Nippon Synthetic Chemical Co., Ltd.] and dried, the same as in Example 9, An artificial leather having a basis weight of 388 g / m ² was obtained. When the water-dispersed polyurethane was coagulated with hot water, the polyurethane did not fall off at 0.1%. In addition, the half-cut surface of the half-cutting machine had no polyurethane unevenness, and the fibrous base material was impregnated with uniform polyurethane. The appearance quality of the obtained artificial leather was good, and the texture was good with no paper-like feeling. Parameter A was 1.1% and parameter B was 4.9%.

[Example 11]
In the water-dispersed polyurethane dispersion B adjusted to a solid content concentration of 20%, an active component of aqueous isocyanate [“Desmodur (registered trademark) N3900” manufactured by Bayer MaterialScience Co., Ltd.] is compared with polyurethane solid content. Except for impregnating the nonwoven fabric with 4% by mass and a dispersion obtained by adding 2.5% by mass of the active ingredient of guar gum of thickening polysaccharide [“Neosoft G” manufactured by Taiyo Kagaku Co., Ltd.] in terms of polyurethane solid content. In the same manner as in Example 9, an artificial leather having a basis weight of 388 g / m ² was obtained.

The drop-out of polyurethane during hot water coagulation of water-dispersed polyurethane was almost 0.1%. In addition, the half-cut surface of the half-cutting machine had no polyurethane unevenness, and the fibrous base material was impregnated with uniform polyurethane. The appearance quality of the obtained artificial leather was good, and the texture was good with no paper-like feeling. Parameter A was 2.5% and parameter B was 14.3%.

[Example 12]
An active ingredient of a carbodiimide-based cross-linking agent [“Carbodilite” (registered trademark) V-02-L2 ”manufactured by Nisshinbo Chemicals Co., Ltd.] was added to the water-dispersed polyurethane dispersion C having a solid content adjusted to 20%. 4% by mass relative to polyurethane solid content, 2% by mass of polyurethane thickener compared to polyurethane solid content, and 2% by mass of active ingredient of guar gum (“Neosoft G” manufactured by Taiyo Kagaku Co., Ltd.) An artificial leather with a basis weight of 386 g / m ² was obtained in the same manner as in Example 9 except that the nonwoven fabric was impregnated with the added dispersion added with 3.0% by mass.

The drop-out of polyurethane during hot water coagulation of water-dispersed polyurethane was almost 0.1%. In addition, the half-cut surface of the half-cutting machine had no polyurethane unevenness, and the fibrous base material was impregnated with uniform polyurethane. The appearance quality of the obtained artificial leather was good, and the texture was good with no paper-like feeling. Parameter A was 1.2% and parameter B was 5.2%.

[Example 13]
Except that the non-woven fabric was not applied with PVA having a saponification degree of 99% and a polymerization degree of 1400 [“NM-14” manufactured by Nippon Synthetic Chemical Co., Ltd.] and drying, in the same manner as in Example 12, An artificial leather having a basis weight of 388 g / m ² was obtained. When the water-dispersed polyurethane was coagulated with hot water, the polyurethane did not fall off at 0.1%. In addition, the half-cut surface of the half-cutting machine had no polyurethane unevenness, and the fibrous base material was impregnated with uniform polyurethane. The appearance quality of the obtained artificial leather was good, and the texture was good with no paper-like feeling. Parameter A was 0.7% and parameter B was 4.0%.

FIG. 1 shows a cross section of the artificial leather obtained in Example 13. The state of the polyurethane and the ultrafine fiber bundle observed in the cross section of FIG. 1 was a state in which the polyurethane cross section was small (polyurethane lump was small), and the adhesion between the ultrafine fiber bundle and the polyurethane was small.

[Comparative Example 1]
Except that the same non-woven fabric as in Example 1 was impregnated with a dispersion obtained by adding 1.2% by mass of magnesium sulfate to the water-dispersed polyurethane dispersion A adjusted to a solid content concentration of 20% with respect to the polyurethane solid content. Produced artificial leather having a basis weight of 223 g / m ^{2 in} the same manner as in Example 1. When the water-dispersed polyurethane was solidified by hot water, the dropping of the polyurethane was 22.1%, and uneven adhesion of the polyurethane to the fibrous base material occurred.

[Comparative Example 2]
Artificial leather having a basis weight of 223 g / m ^{2 in} the same manner as in Example 1 except that the same non-woven fabric as in Example 1 was impregnated with the water-dispersed polyurethane dispersion B having a solid content adjusted to 20%. Got. When the polyurethane was hot-water coagulated, the dropping of the polyurethane was 15.1%, and uneven adhesion of the polyurethane to the fibrous base material occurred.

[Comparative Example 3]
The same non-woven fabric as in Example 1 was impregnated with the water-dispersed polyurethane dispersion B adjusted to a solid content concentration of 20%, treated in a moist heat atmosphere at a temperature of 97 ° C. and a humidity of 100% for 5 minutes, and then at 110 ° C. The weight per unit area is 223 g / m ^{2 in the same} manner as in Example 1 except that it is dried at a temperature for 15 minutes and a water-dispersed polyurethane resin is applied so that the polyurethane mass relative to the island component mass of the nonwoven fabric is 35 mass%. Of artificial leather. The drop-out of the polyurethane during hot water coagulation of the water-dispersed polyurethane was 0.0%, but the texture of the obtained artificial leather had a strong paper-like feeling. Parameter A was 7.9% and parameter B was 42.2%.
[Comparative Example 4]
The water-dispersed polyurethane dispersion B having a solid content adjusted to 20% was impregnated into the same nonwoven fabric as in Example 13, treated at a temperature of 97 ° C. and a humidity of 100% for 5 minutes, and then 110 ° C. The weight per unit area is 389 g / m ^{2 in the same} manner as in Example 13, except that the polyurethane is mass-dried at a temperature for 15 minutes, and the water-dispersible polyurethane resin is applied so that the mass of polyurethane with respect to the mass of island components of the nonwoven fabric is 28 mass%. Of artificial leather. The drop-out of the polyurethane during hot water coagulation of the water-dispersed polyurethane was 0.0%, but the texture of the obtained artificial leather had a strong paper-like feeling. Parameter A was 8.1% and parameter B was 43.1%.

FIG. 2 shows a cross section of the artificial leather obtained in Comparative Example 4. The state of the polyurethane and the ultrafine fiber bundle observed in the cross section of FIG. 2 was a state where there were many polyurethane cross sections (polyurethane mass was large) and there was much adhesion between the ultrafine fiber bundle and the polyurethane.

The results of Examples 1 to 7 and Comparative Examples 1 to 4 are summarized in Tables 1 and 2.

In the example, since the value of parameter A is smaller than that of the comparative example, the polyurethane lump is small, and the polyurethane is uniformly dispersed inside the artificial leather, giving a soft texture. Furthermore, since the parameter B is smaller than that of the comparative example, the embodiment has less adhesion between the ultrafine fiber bundle and the polyurethane, and has a soft texture.

1: polyurethane lump 2: outer periphery of ultrafine fiber bundle 3: outer periphery covered with polymer elastic body coating

Claims

A cross-section cut in the thickness direction of the sheet-like material, wherein the fibrous base material comprising ultrafine fibers and / or bundles of ultrafine fibers is provided with a polymer elastic body having a hydrophilic group as a binder. In the polymer elastic body observed in the cut surface, the occupation ratio of the portion having a cross-sectional area of 50 μm 2 or more independently is 0.1% or more to the area of the artificial leather cross-section in the observation field of view 5 A sheet-like material characterized by being not more than 0%.
2. The cross section cut in the thickness direction of the sheet-like material, wherein 1% or more and 35% or less of the outer periphery of the cross section of the ultrafine fiber and / or ultrafine fiber bundle is covered with the polymer elastic film. Sheet-like material.
3. The sheet-like material according to claim 1 or 2, wherein the polymer elastic body has a structure crosslinked by a crosslinking agent.
In a method for producing a sheet-like material, in which a polymeric elastic body having a hydrophilic group is applied as a binder to a fibrous base material made of ultrafine fibers, an aqueous system containing a polymeric elastic body and a thickener dispersed in water A method for producing a sheet-like material, comprising applying a resin dispersion to a fibrous base material and coagulating the polymer elastic body in hot water at a temperature of 50 to 100 ° C.
The method for producing a sheet-like product according to claim 4, wherein the aqueous resin dispersion exhibits non-Newtonian properties.
The method for producing a sheet-like product according to claim 4 or 5, wherein the thickener is a nonionic thickener.
The method for producing a sheet-like material according to any one of claims 4 to 6, wherein the aqueous resin dispersion exhibits thixotropic properties.
The method for producing a sheet-like product according to any one of claims 4 to 7, wherein the thickening agent is a thickening polysaccharide.
The method for producing a sheet-like product according to any one of claims 4 to 8, wherein the thickener is guar gum.
The method for producing a sheet-like material according to any one of claims 4 to 9, wherein the aqueous resin dispersion contains a heat-sensitive coagulant.
The method for producing a sheet-like material according to any one of claims 4 to 10, wherein the aqueous resin dispersion contains a crosslinking agent.
The method for producing a sheet-like material according to any one of claims 4 to 11, wherein the polymer elastic body is water-dispersed polyurethane.