JP2017172074A - Sheet-like article and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet-like article especially excellent in wet heat resistance and good in surface quality and feeling by conducting a cure treatment after heating treatment in a liquid bath in an environment friendly manufacturing process.SOLUTION: There is provided a manufacturing method of a sheet-like article by conducting following processes (1) to (3) in this order in a manufacturing procedure of the sheet-like article having surface piloerection consisting of water dispersion type polyurethane which is solidified with a fibrous substrate. (1) a process for impregnating a water dispersion type polyurethane dispersion into the fibrous substrate and solidifying them. (2) a process for heat treating in a liquid bath at a temperature of 80°C to 150°C. (3) a process for conducting a cure treatment at a temperature of 150°C to 210°C. There is provided a manufacturing method of a sheet-like article where a crosslinking agent consists of a carbodiimide-based or block isocyanate-based crosslink and the water dispersion type polyurethane is crosslinked by the crosslinking agent.SELECTED DRAWING: None

Description

  The present invention relates to an environmentally-friendly sheet-like material that does not use an organic solvent in the production process and a method for producing the same, and particularly to a sheet-like material that is excellent in wear resistance and strength, has good surface quality and texture, and the production thereof. It is about the method.

  A fibrous base material mainly made of a fabric such as a nonwoven fabric and a sheet-like material made of polyurethane have excellent characteristics not found in natural leather, and are widely used for various uses 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 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, for example, a method using a water-dispersed polyurethane liquid in which polyurethane is dispersed in water instead of the conventional organic solvent-based polyurethane has been studied.

  However, a sheet-like material obtained by impregnating a fibrous base material with a water-dispersible polyurethane solution and coagulating polyurethane easily deteriorates in physical properties when wet, breaks when dyeing, or product properties under high humidity conditions. There is a problem that decreases. In order to suppress deterioration of physical properties due to the application of the water-dispersed polyurethane, a method of curing the fiber base material impregnated with the water-dispersed polyurethane liquid at a temperature of 100 ° C. or higher and 200 ° C. or lower, or a crosslinking agent There has been proposed a method of cross-linking polyurethane by using (see Patent Documents 1 and 2). However, in these proposals, if a fiber base material impregnated and solidified with water-dispersed polyurethane and cured and / or a fiber base material cross-linked with polyurethane is subjected to a dyeing process, As a result, the physical properties were not maintained, and the physical properties could not be maintained as before.

WO2015 / 115290 publication JP 2004-84142 A

  Therefore, in view of the background of the above prior art, the object of the present invention is to provide a curing process after a heat treatment in a liquid bath by an environmentally-friendly manufacturing process, which is particularly excellent in wear resistance and strength, surface quality and texture. Is to provide a method for producing an excellent sheet.

  Another object of the present invention is to provide a sheet-like material having excellent wear resistance and strength, and excellent surface quality and texture.

The present invention is intended to achieve the above-described problem, and the method for producing a sheet-like material according to the present invention comprises producing a sheet-like material having a surface nap consisting of a fibrous base material and solidified water-dispersed polyurethane. A method for producing a sheet-like material, characterized in that the following steps (1), (2) and (3) are performed in order.
(1) a step of impregnating and solidifying a fibrous base material with a water-dispersed polyurethane dispersion;
(2) The process of heat-processing with the liquid bath of temperature 80 to 145 degreeC,
(3) A step of curing at a temperature of 150 ° C to 210 ° C.

  According to a preferred embodiment of the method for producing a sheet-like product of the present invention, the solidified water-dispersed polyurethane has a structure crosslinked with a crosslinking agent.

  According to a preferred embodiment of the method for producing a sheet-like product of the present invention, the crosslinking agent is a carbodiimide crosslinking agent and / or a blocked isocyanate crosslinking agent.

  According to a preferred embodiment of the method for producing a sheet-like product of the present invention, the softened point of the solidified water-dispersed polyurethane is 150 ° C. or higher and 240 ° C. or lower.

  The sheet-like material of the present invention is a sheet-like material having a surface raised consisting of a water-dispersible polyurethane coagulated with a fibrous base material, and has a wear loss of 10 mg or less in 20,000 Martindale abrasion tests. Is a sheet-like product having a grade 4 or higher and a dyed product having a wet stress retention of 70% or higher.

  According to a preferred embodiment of the sheet-like material of the present invention, the coagulated water-dispersed polyurethane has a structure crosslinked with a crosslinking agent.

  According to a preferred embodiment of the sheet-like material of the present invention, the crosslinking agent is a carbodiimide crosslinking agent and / or a blocked isocyanate crosslinking agent.

  According to a preferred embodiment of the sheet-like material of the present invention, the softened point of the solidified water-dispersed polyurethane is 150 ° C. or higher and 240 ° C. or lower.

  According to the present invention, by carrying out a curing treatment after a heat treatment in a liquid bath by an environmentally friendly manufacturing process, a sheet-like material having particularly excellent wear resistance and strength, and excellent surface quality and texture can be obtained. Can do.

  A specific form for carrying out the present invention will be described next.

[Method for producing sheet-like material]
First, the manufacturing method of the sheet-like material of this invention is demonstrated concretely. The method for producing a sheet-like product of the present invention is, as described above, preferably a sheet-like product in which a fibrous base material is impregnated with a water-dispersed polyurethane dispersion as a binder and solidified, and a cross-linking agent is preferably applied and heated. It is a manufacturing method.

  As the fibrous base material used in the present invention, fabrics such as woven fabrics, knitted fabrics and nonwoven 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 used in 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 can 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 fiber 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 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. 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. Moreover, as a fibrous base material, it is also allowed to 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 a fiber having an elliptical shape, a flat shape such as a flat shape or a triangular shape, or a fiber shape having a different shape such as a sector shape or a cross shape may be employed.

  Moreover, it is preferable that the average fiber diameter of the single fiber which comprises a fibrous base material is 0.1-7 micrometers, More preferably, it is 0.3-5 micrometers. By making the average fiber diameter of the single 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, a woven fabric or a knitted fabric can be combined with the nonwoven fabric for the purpose of improving the strength. As the combination of the nonwoven fabric and the woven fabric or the knitted fabric, any method such as laminating the woven fabric or the knitted fabric on the nonwoven fabric or inserting the woven fabric or the knitted fabric into the nonwoven fabric can be adopted. In this case, among these, it is preferable to use a woven fabric from the viewpoint that improvement in form stability and strength can be expected.

  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. A preferred embodiment is a single yarn 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, but these strongly 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 strongly twisted yarn, the number of twists is preferably 1000 T / m or more and 4000 T / m or less, and more preferably 1500 T / m or more and 3500 T / m or less. When the number of twists is less than 1000 T / m, the number of single fibers constituting the strongly 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 yarn constituting the woven fabric or knitted fabric becomes too hard, and thus tends to cause hardening of the texture.

  Moreover, in this invention, it is a preferable aspect to use the fiber obtained from an ultrafine fiber expression type fiber for a fibrous base material. By using the fiber obtained from the ultrafine fiber expression type fiber as 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 bundles of ultrafine fibers (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.

  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 composite fiber or a peelable composite fiber in which two-component thermoplastic resins are arranged alternately in a radial or multilayer manner on the fiber cross section, and each component is peeled and divided to split 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, a copolymerized polyester obtained by copolymerizing alkali-decomposable sodium sulfoisophthalic acid or polyethylene glycol that can be decomposed without using an organic solvent, polylactic acid, and hot water-soluble polyvinyl alcohol are preferably used.

  As for the 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 0.8. . 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.

  Moreover, it is preferable that the long diameter of the single fiber of ultra fine fiber expression type | mold fibers, such as a sea-island type composite fiber, is 5-80 micrometers, More preferably, it is 10-50 micrometers. If the single fiber fineness 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. In addition, when the single fiber fineness is larger than 80 μm, efficient entanglement may not be possible by needle punch processing or the like.

  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.

  In addition, in order to laminate and integrate a nonwoven fabric used as a fibrous base material and a woven fabric or a knitted fabric, needle punch processing, water jet punch processing, or the like is preferably used from the viewpoint of fiber entanglement. Among them, the needle punching treatment is not limited to the sheet thickness, and is preferably used because the fibers can be oriented in the vertical direction of the fibrous base material.

  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 preliminarily entangling by the needle punching process is adopted, it is effective to perform the punch density at 20 / cm ² or more, and preferably 100 / Pre-entanglement is preferably given at a punch density of cm ² or more, more preferably pre-entanglement is given at a punch density of 300 / cm ^{2 to} 1300 / cm ² .

At a punch density of less than 20 pre-entanglements / cm ² , the width of the non-woven fabric remains narrowed by the needle punching 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, 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 a woven fabric or a knitted fabric, when the fibers constituting the nonwoven fabric are entangled by needle punching, the punch density is preferably 300 / cm ^{2 to} 6000 / cm ^2. a more preferred embodiment be a 1000 ^/ cm 2 to 3000 present / 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 the fibers are entangled with each other by needle punching. It can be a substrate.

  Moreover, when performing a water jet punch process, it is preferable to perform water in the state of a columnar flow. Specifically, it is preferable to eject water 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 non-woven 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 less than 0.3 mm, the sheet form stability 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.

  From the viewpoint of densification, it is preferable that the nonwoven fabric made of ultrafine fiber-generating fibers thus obtained is shrunk by dry heat treatment or wet heat treatment or both to further increase the density.

  The sea-sea removal treatment for removing the sea component of the sea-island type composite fiber in the case of using the sea-island type composite fiber is performed before and / or after the application of the water-dispersed polyurethane dispersion containing the water-dispersed polyurethane to the fibrous base material. Can be done later. 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 inhibitor application can be performed either before or after the sea removal treatment. By applying the inhibitor before the sea removal treatment, it is possible to increase the form retention of the fibrous base material in the sea removal treatment process in which the fabric weight of the fiber is lowered and the tensile strength of the sheet is lowered. For this reason, since the sheet | seat of a thin thing can be processed stably, since the thickness retention of the fibrous base material in a sea removal process can be raised, the densification of a fibrous base material can be suppressed. . On the other hand, since the densification is performed after the sea removal treatment, the fibrous base material can be densified. Therefore, 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, application of high water saponification degree PVA, which is more difficult to water, makes it difficult to elute the inhibitor at the time of application of the water-dispersed polyurethane dispersion, so that adhesion between ultrafine fibers and polyurethane can be further inhibited.

  The high saponification degree PVA preferably has a saponification degree of 95% or more and 100% or less, and 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 degree of polymerization of PVA is preferably 500 or more and 3500 or less, more preferably 500 or more and 2000 or less. By making the polymerization degree of PVA 500 or more, elution of the high saponification degree PVA at the time of applying the polyurethane dispersion can be suppressed, and by making the polymerization degree of PVA 3500 or less, the high saponification degree PVA liquid The viscosity of the saponification does not become too high, and the 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, more preferably 5% by mass or more and 60% by mass or less, with respect to the fibrous base material remaining in the product. By applying 0.1% by mass or more of high saponification degree PVA, it is possible to suppress the form stability effect in the sea removal treatment process and the non-attachment property of the ultrafine fibers and polyurethane, and the high saponification degree PVA is 80%. By applying the mass% or less, the adhesion between the ultrafine fibers and the polyurethane does not decrease too much, the raised fibers become uniform, and a product with 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, a method of dissolving the inhibitor in water, impregnating the fibrous base material, and drying by heating is preferable. Used. If the drying temperature is too low, the 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. Therefore, the drying is performed at a temperature of 80 ° C. or higher and 180 ° C. or lower. It is preferably 110 ° C. or higher and 160 ° C. or lower. 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 can be dissolved and removed 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 can be used, and when the sea component is a copolymer polyester or polylactic acid, An alkaline solution such as an aqueous sodium hydroxide solution can be used, and when the sea component is polyvinyl alcohol, hot water can be used.

  Next, the water-dispersed polyurethane used in the present invention will be described.

  As the polyurethane, a resin obtained by a reaction of 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.

  Examples of the polyether-based polyol in the above-described polymer polyol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like, and copolymer polyols obtained by combining them.

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

  Examples of the low molecular weight polyol include ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, 1,10- Linear alkylene glycol such as decanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 2-methyl-1,8-octanediol, etc. One or more selected from branched alkylene glycols, alicyclic diols such as 1,4-cyclohexanediol, and aromatic dihydric alcohols such as 1,4-bis (β-hydroxyethoxy) benzene are used. be able to. Further, addition products obtained by adding various alkylene oxides to bisphenol A can also be used.

  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 One kind or two or more kinds selected from isophthalic acid can be mentioned.

  Examples of the polylactone polyol include polylactone polyols obtained by ring-opening polymerization of γ-butyrolactone, γ-valerolactone, ε-caprolactone, or the like alone or in a mixture of two or more thereof using a 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 and diaryl carbonate.

  As the polyol for the production raw material of the polycarbonate polyol, the polyols mentioned as the production raw material for 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.

  As the water-dispersible polyurethane used in the present invention, a hydrophilic group-containing polyurethane can be used.

  In the hydrophilic group-containing polyurethane used in the present invention, examples of the component that causes the resin 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.

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

  Examples of the compound containing a cationic group and active hydrogen include tertiary amino group-containing compounds such as 3-dimethylaminopropanol, N-methyldiethanolamine, 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.

  By introducing a sulfonic acid group and a carboxyl group, among other hydrophilic group-containing active hydrogen components, into the polyurethane, not only to increase the hydrophilicity of the polyurethane molecule, but also by using a crosslinking agent described later in combination, Since a three-dimensional crosslinked structure can be imparted to the polyurethane molecule and the physical properties can be improved, it is preferable to produce the hydrophilic group-containing active hydrogen component by appropriately selecting it.

  As the chain extender used in the production of polyurethane, compounds used in conventional production of polyurethane can be used, and among them, the molecular weight of 600 or less having two or more active hydrogen atoms capable of reacting with an isocyanate group in the molecule. Low molecular weight compounds are preferably used. 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 include diamines such as 4′-dicyclohexylmethanediamine, triamines such as diethylenetriamine, and amino alcohols such as aminoethyl alcohol and aminopropyl alcohol.

  Examples of organic polyisocyanates used in the production of polyurethane include aliphatic diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate (hereinafter sometimes abbreviated as IPDI), water-added xylylene diisocyanate, dicyclohexylmethane diisocyanate ( Hereinafter, alicyclic diisocyanates such as hydrogenated MDI), and aromatics such as xylylene diisocyanate (hereinafter sometimes abbreviated as XDI) and tetramethyl-m-xylylene diisocyanate. / Aliphatic diisocyanate, tolylene diisocyanate (hereinafter sometimes abbreviated as TDI), 4,4′-diphenylmethane diisocyanate (hereinafter sometimes abbreviated as MDI), tolidine diisocyanate, and And aromatic diisocyanates such as naphthalene diisocyanate (hereinafter sometimes abbreviated as NDI).

  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 neutralizing agent used in the hydrophilic group-containing active hydrogen component is not particularly specified before or after the polyurethane polymerization step or before or after the dispersion step in the aqueous medium, but from the viewpoint of stability in the aqueous dispersion of polyurethane, the neutralizing agent is used. It is preferably added before the dispersion step or during the dispersion step in an 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-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 the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants. Surfactant may be used independently and can also use 2 or more types together.

  Examples of nonionic surfactants include alkylene oxide addition types such as polyoxyethylene nonylphenyl ether, polyoxyethylene laurel ether and polyoxyethylene stearyl ether, and polyhydric alcohol types such as glycerin monostearate. Examples of the anionic surfactant include sodium laurel sulfate, ammonium lauryl sulfate, and sodium dodecylbenzenesulfonate.

  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.

  The polyurethane dispersion used in the present invention can be produced by applying a conventional method for producing a polyurethane dispersion. 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 can be carried out in the absence of a solvent, and can also be carried out in an organic solvent such as methyl ethyl ketone, toluene and acetone.

  An aqueous dispersion type polyurethane dispersion containing the water dispersion type polyurethane synthesized as described above is applied to the fibrous base material by immersing it in the fibrous base material, and then heated and dried to obtain the polyurethane. Solidify and solidify.

  The water-dispersed polyurethane used in the present invention preferably has a sulfonic acid group, a carboxyl group, a hydroxyl group, or a primary or secondary amino group, and is crosslinked with a crosslinking agent having reactivity with these functional groups. As a crosslinking method, it is contained in a polyurethane dispersion or applied after polyurethane coagulation, so that the resin has a high molecular weight after the reaction and the crosslinking density of the resin is increased, so that durability, weather resistance, heat resistance and wetness are increased. The strength retention rate of can be improved.

  As the crosslinking agent, those having two or more reactive groups in the molecule capable of reacting with the reactive groups introduced into the polyurethane can be used. Specifically, water-soluble isocyanate compounds and block isocyanate compounds are used. And polyisocyanate crosslinking agents such as melamine crosslinking agents, oxazoline crosslinking agents, carbodiimide crosslinking agents, aziridine crosslinking agents, epoxy crosslinking agents, and hydrazine crosslinking agents. 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 organic polyisocyanate-containing compounds. Examples of commercially available products include “Baihijoule” (registered trademark) series, “Death Module” (registered trademark) series, and the like 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 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-based 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 preferable as a functional group possessed by polyurethane is a hydroxyl group and / or a carboxyl group and / or a sulfonic acid group, and a preferable crosslinking agent as a crosslinking agent is a blocked isocyanate crosslinking agent and a carbodiimide compound.

  A crosslinking agent can also be added to the polyurethane dispersion. When the crosslinking agent is added, the addition amount is preferably 3.0% by mass or less, more preferably 0.5% by mass or less, relative to the polyurethane solid content. Further, the crosslinking agent may be added after impregnation and coagulation of polyurethane, and when added, the addition amount is preferably 3.0% by mass or less, more preferably 0.5% by mass relative to the polyurethane solid content. It is below mass%. In any case, when the addition amount of the crosslinking agent is 3.0% or more, the texture may become hard.

  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 preferably included.

  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 viewpoints of storage stability and texture of the fiber product after processing.

  In addition to the above-mentioned heat-sensitive coagulant, the following various additives can be further added to the water-dispersed polyurethane dispersion. For example, pigments such as carbon black, antioxidants (hindered phenol-based, 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, fluorine compounds such as fluoroalkyl ester polymers of acrylic acid) , Wetting agents (wetting agents such as ethylene glycol, diethylene glycol, propylene glycol, glycerin), antifoaming agents (foaming agents such as octyl alcohol, sorbitan monooleate, polydimethylsiloxane, polyether-modified silicone, fluorine-modified silicone), filling Agent (calcium carbonate, titanium oxide Silica, talc, ceramics, fine particles such as resin, fillers such as hollow beads), flame retardants (halogen, phosphorus, antimony, melamine, guanidine, guanylurea, silicone and inorganic flame retardants) ), Microballoon (eg: Matsumoto Yushi: Matsumoto Microsphere (registered trademark)), foaming agent [eg, dinitrosopentamethylenetetramine (eg, “Cermic A” (registered trademark) manufactured by Sankyo Kasei), azodicarbon Amides (eg, “Cermic CAP” (registered trademark) manufactured by Sankyo Kasei), p, p′-oxybisbenzenesulfonyl hydrazide (eg, “Cermic S” (registered trademark) manufactured by Sankyo Kasei), N, N′— Organic blowing agents such as dinitrosopentamethylenetetramine (eg, “Cellular GX” (registered trademark) manufactured by Eiwa Kasei) and sodium hydrogen carbonate (Example: Inorganic foaming agents such as “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 modifiers, plasticizers (phthalic acid esters, adipic acid esters, etc.) and mold release agents (wax, metal soap, or mixed release agents, etc.) ) And the like can be contained.

  Examples of the coagulation method of the water-dispersed polyurethane include a method using wet heat with steam, dry heat with hot air, infrared rays, hot water, and an acid solvent. Of these, hot water coagulation and acid coagulation are preferably used from the viewpoint of softening the texture.

  After the application of the water-dispersible polyurethane, dividing the obtained polyurethane-applied sheet material into half or several sheets in the sheet thickness direction is a preferable aspect with excellent production efficiency.

  Before the raising treatment described later, a lubricant such as a silicone emulsion can be applied to the water-dispersed polyurethane-applied sheet. Moreover, applying an antistatic agent before the raising treatment is a preferable aspect 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, napping 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-like material is too thin, physical properties such as tensile strength and tearing strength of the sheet-like material will be weak, and if too thick, the texture of the sheet-like material will be hard, so about 0.1 to 5.0 mm Preferably there is.

  The sheet 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. Therefore, the dyeing temperature can be set depending on the type of fiber, and generally 80 ° C. or higher and 145 ° C. It is preferable that it is below, More preferably, it is 110 degreeC or more and 130 degrees C or less.

  The dye 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 dyeing with a disperse dye, reduction washing can be performed after dyeing.

  It is also a preferred embodiment 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.

  In the present invention, it is important to cure at 150 to 210 ° C. after the liquid bath treatment. The water-dispersible polyurethane generally contains the aforementioned hydrophilic group in the molecule in order to disperse the polyurethane molecule in an aqueous solvent during the polymerization. Therefore, when heat-treating a sheet-like material impregnated with water-dispersed polyurethane in a high-temperature and / or high-pressure liquid bath such as a dyeing process, water molecules penetrate into the polyurethane molecules, and the polyurethane molecular structure becomes loose, Degradation of physical properties occurs. However, after the heat treatment in this liquid bath, the sheet-like material is cured in the temperature range of 150 ° C. to 210 ° C. to improve the thermal mobility of the polyurethane molecules, thereby restructuring the polyurethane structure into a strong one. And the physical properties can be improved.

  If the curing time is too short, the structure of the water-dispersed polyurethane is not thermally stabilized and reconstructed, and a strong polyurethane resin cannot be obtained. On the other hand, if the length is too long, the workability deteriorates, and therefore it is preferably 5 minutes or longer and 60 minutes or shorter, more preferably 10 minutes or longer and 40 minutes or shorter.

  On the other hand, if the temperature of the cure is too low, the thermal mobility of the polyurethane is not sufficiently increased, and a strong structure cannot be reconstructed. On the other hand, if the temperature is too high, the fluidity of the polyurethane becomes too high, and the structure of adhesion to the fibers changes greatly. Therefore, the curing temperature is in the range of 150 ° C. to 210 ° C., preferably the softening point of the solidified polyurethane is −50 ° C. to −0 ° C., more preferably in the range of −40 ° C. to −10 ° C.

  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 vehicle interiors such as automobiles, trains and aircraft. Interior materials with an elegant appearance, shirts, jackets, casual shoes, sports shoes, shoes uppers such as men's shoes and women's shoes, trims, bags, belts, wallets, etc., and clothing used for some of them It can be suitably used as industrial materials such as materials, wiping cloths, polishing cloths and CD curtains.

  Next, the manufacturing method of the sheet-like material of the present invention will be described in more detail with reference to examples.

[Evaluation method]
(1) 10% elongation stress retention when wet:
In accordance with JIS L1913 6.3.1 (2010 edition), using a constant speed extension type tensile tester, 10 of the dyed sheet-like material under the conditions of a sample width of 2 cm, a grip length of 10 cm, and a tensile speed of 10 cm / min. The stress at% elongation (N / cm) was measured at N = 5 for drying and for the wet state after the sheet-like material was immersed in room temperature water for 10 minutes, respectively. Stress retention rate (%) at the time of 10% elongation at the time of wet stress (average of N = 5) / dry stress (average of N = 5) × 100 was evaluated.

(2) Abrasion resistance of sheet-like material:
Martindale wear evaluation (durability evaluation) was performed. As a Martindale abrasion tester, James H. Heal & Co. Using the model 406 made by the company, and using the company's ABRASIVE CLOTH SM25 as the standard friction cloth, applying a load equivalent to 12 kPa to the artificial leather sample, the appearance of the artificial leather after rubbing under the condition of 20,000 wear times It was visually observed and evaluated. As the evaluation criteria, those in which the appearance of the artificial leather had not changed at all before the friction were classified as grade 5, those in which a large number of pills were generated were classified as grade 1, and the interval was divided into 0.5 grades. Grades 4 through 5 were accepted.

(3) Appearance quality of sheet-like material:
As for the appearance quality of the sheet, 10 healthy adult men and 10 adult women each, with a total of 20 evaluators, the visual and sensory evaluations were evaluated in the following five levels, and the most common evaluation was the appearance quality. did. Appearance quality was graded 4-5.
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-like material:
As for the texture of the sheet, 10 healthy adult men and 10 adult women each, with a total of 20 evaluators, the sensory evaluation with tactile sensation is evaluated in the following four levels, and the most common evaluation is the texture. It was evaluated. As for the texture, ◎, ○, and △ were good (flexible and excellent in wrinkle recovery property).
(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.
○: It has the same flexibility and crease wrinkle recovery properties as an artificial leather to which an organic solvent-based polyurethane with the same basis weight is applied.
Δ: Although the softness and the crease recovery property are inferior to those of the artificial leather to which the organic solvent-based polyurethane having the same basis weight is applied, it is relatively soft and the crease recovery property is also good.
X: The sheet is hard and has a paper-like feel.

[Preparation of polyurethane dispersion]
Using polyhexamethylene carbonate with Mn of 2,000 for polyol, IPDI for isocyanate, 2,2-dimethylolpropionic acid as an intramolecular hydrophilic group, and making a prepolymer in acetone solvent, After adding ethylene glycol, polyoxyethylene nonylphenyl ether and water as external emulsifiers, chain elongation reaction and emulsification, acetone is removed by decompression and the softening point after solidification is 200 ° C. A polyurethane dispersion 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 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 5 minutes to shrink and dried at a temperature of 100 ° C. for 10 minutes. Next, an aqueous solution prepared by adjusting PVA having a saponification degree of 99% and a polymerization degree of 1400 [“NM-14” manufactured by Nippon Synthetic Chemical Co., Ltd.] 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 removal sheet, the water-dispersed polyurethane dispersion, the associative thickener [Sickner 627N manufactured by San Nopco Co., Ltd.] active ingredient is 4% by mass relative to the polyurethane solid content, and magnesium sulfate is added to the polyurethane solid content. After impregnating the added dispersion of 1.2% by mass, treating in hot water at a temperature of 95 ° C. for 3 minutes and then drying with hot air at a drying temperature of 100 ° C. for 15 minutes, the mass of polyurethane is 31% by mass relative to the mass of island components of the nonwoven fabric. Thus, a sheet provided with water-dispersed polyurethane was obtained.

  Next, it 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. After drying, the concentration of the carbodiimide-based crosslinking agent [“Carbodilite” (registered trademark) V-02-L2] manufactured by Nisshinbo Chemical Co., Ltd.] is applied to the sheet in an amount of 5% by mass based on the amount of polyurethane applied. After impregnating the prepared solution, the mixture was heated with a dryer at a temperature of 120 ° C. for 20 minutes to accelerate the crosslinking reaction with drying.

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. did. Next, it is dyed with disperse dyes in a liquid bath at a temperature of 120 ° C. using a circular dyeing machine, subjected to reduction cleaning, dried at a temperature of 100 ° C. for 20 minutes, cured at a temperature of 160 ° C. for 30 minutes, and a basis weight of 255 g / m. ² artificial leathers were obtained. The obtained artificial leather had good wear resistance and appearance quality, and a good texture. Further, the stress retention at 10% elongation when the dyed product after curing was wet was 75%. The results are shown in Table 1.

[Example 2]
The basis weight is 258 g / m ^{2 in} the same manner as in Example 1 except that the crosslinking agent to be applied is changed to a blocked isocyanate type [“Elastoron” (registered trademark) BN-69 ”manufactured by Daiichi Kogyo Seiyaku Co., Ltd.]. An artificial leather was obtained. The obtained artificial leather had good wear resistance and appearance quality, and a good texture. Moreover, the 10% elongation stress retention when wet of the dyed product after curing was 74%. The results are shown in Table 1.

[Example 3]
An artificial leather having a basis weight of 263 g / m ² was obtained in the same manner as in Example 1 except that the crosslinking agent was added to the polyurethane dispersion. The obtained artificial leather had both good wear resistance and appearance quality, and a good texture. Further, the stress retention at 10% elongation when the dyed product after curing was wet was 72%. The results are shown in Table 1.

[Example 4]
An artificial leather having a basis weight of 266 g / m ² was obtained in the same manner as in Example 1 except that the heat treatment temperature in the liquid bath was 100 ° C. The obtained artificial leather had both good wear resistance and appearance quality, and a good texture. Further, the stress retention at 10% elongation when the dyed product after curing was wet was 76%. The results are shown in Table 1.

[Example 5]
An artificial leather having a basis weight of 270 g / m ² was obtained in the same manner as in Example 1 except that the curing temperature was 180 ° C. The obtained artificial leather had both good wear resistance and appearance quality, and a good texture. Further, the stress retention at 10% elongation when the dyed product after curing was wet was 78%. The results are shown in Table 1.

[Comparative Example 1]
An artificial leather having a basis weight of 260 g / m ² was obtained in the same manner as in Example 1 except that no curing was performed after the liquid bath treatment. The obtained artificial leather had pilling and poor wear resistance, and the appearance quality was rough, with the surface nap being disturbed. The texture was also good. Further, the 10% elongation stress retention when wet of the dyed product after curing was as low as 51%. The results are shown in Table 2.

[Comparative Example 2]
An artificial leather having a basis weight of 260 g / m ² was obtained in the same manner as in Example 1 except that the timing of curing was immediately after the fibrous base material was impregnated with water-dispersed polyurethane and solidified. The obtained artificial leather was good in both wear resistance and appearance quality. The texture was also good. However, the stress retention at 10% elongation when the dyed product after curing was wet was as low as 59%. The results are shown in Table 2.

[Comparative Example 3]
An artificial leather having a basis weight of 265 g / m ² was obtained in the same manner as in Example 1 except that the curing temperature was 220 ° C. The obtained artificial leather had pilling and poor wear resistance, and the appearance quality was rough, with the surface nap being disturbed. The texture is also very hard. Further, the 10% elongation stress retention when wet of the dyed product after curing was as low as 51%. The results are shown in Table 2.

[Comparative Example 4]
An artificial leather having a basis weight of 265 g / m ² was obtained in the same manner as in Example 1 except that the curing temperature was 140 ° C. The obtained artificial leather had good appearance quality and texture, but pilling occurred and its wear resistance was poor. Further, the 10% elongation stress retention when wet of the dyed product after curing was as low as 55%. The results are shown in Table 2.

Claims (8)

A method for producing a sheet-like material having a surface nap made of a water-dispersible polyurethane coagulated with a fibrous base material, wherein the following steps (1), (2), and (3) are performed in order: The manufacturing method of the sheet-like thing to do.
(1) A step of impregnating and solidifying a fibrous base material with a water-dispersed polyurethane dispersion (2) A step of heat treatment in a liquid bath at a temperature of 80 ° C. to 145 ° C. (3) A curing treatment at a temperature of 150 ° C. to 210 ° C. Process   2. The method for producing a sheet-like product according to claim 1, wherein the solidified water-dispersed polyurethane has a structure crosslinked by a crosslinking agent.   The method for producing a sheet-like product according to claim 2, wherein the crosslinking agent is a carbodiimide crosslinking agent and / or a blocked isocyanate crosslinking agent.   The method for producing a sheet-like product according to any one of claims 1 to 3, wherein the softened point of the solidified water-dispersed polyurethane is 150 ° C to 240 ° C. A sheet-like product having a surface nap consisting of a fibrous base material and water-dispersible polyurethane,
A sheet-like product characterized by a weight loss of 10 mg or less in a 20,000 martindale abrasion test, a pilling evaluation of 4 or higher, and a wet stress retention of a dyed product of 70% or higher.   6. The sheet-like material according to claim 5, wherein the solidified water-dispersed polyurethane has a structure crosslinked by a crosslinking agent.   The sheet-like product according to claim 6, wherein the crosslinking agent is a carbodiimide crosslinking agent and / or a blocked isocyanate crosslinking agent.   The sheet-like material according to any one of claims 5 to 7, wherein the softened point of the solidified water-dispersed polyurethane is 150 ° C to 240 ° C.