JP2011069018A - Leather-like sheet and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a leather-like sheet which has a hand giving a sense of oneness and flexibility, has a high grade appearance free from the irregularity of gloss, and giving a sense of fulfillment similar to that of natural leather, and to provide a method for producing the same. <P>SOLUTION: There are provided: the leather-like sheet produced by laminating a grain side layer prepared by melting a polyurethane nonwoven fabric to at least one side of a substrate layer through a thermally adhesive resin layer; and a method for producing a leather-like sheet, including laminating a thermally adhesive resin having a softening temperature lower by 20°C or more than the softening temperature of a polyurethane resin constituting the polyurethane nonwoven fabric between a substrate layer and the polyurethane nonwoven fabric and then softening and melting the thermally adhesive resin layer to integrally laminate the substrate layer to the grain side layer prepared by melting the polyurethane nonwoven fabric. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  In the present invention, the surface has a surface layer made of a melted layer of polyurethane nonwoven fabric in which micropores are formed, and the surface layer and the underlying substrate layer are randomly formed. A leather-like sheet having a texture and flexibility with a sense of unity, a high-quality appearance with no unevenness of gloss, and a fullness close to that of natural leather by fusing with a small amount of adhesive resin distributed, and its It relates to a manufacturing method.

  Conventionally, many proposals have been made regarding methods for producing a leather-like sheet having a silver surface. Many of these proposals are methods for forming a silver surface by providing a wet solidified layer or a dry solidified layer made of a polymer elastic body on one surface of a fiber sheet. In addition, many proposals have been made for a method for producing a silver-finished leather-like sheet having air permeability and moisture permeability. These methods include adding foaming agents, additives, coagulation regulators, etc. to the fiber surface and laminating a breathable porous layer formed by wet coagulation or dry coagulation, or using laser beams, etc. For example, a hole is made in the surface silver layer.

As a method for producing a leather-like sheet having a natural leather-like appearance and having air permeability and moisture permeability, a method of heat-melting the surface of a fibrous sheet containing a polymer elastic body, or a fiber or elastic body on the surface There has also been proposed a method of forming a silver surface by applying a solvent (1) to melt the fiber or polymer elastic body constituting the surface of the sheet to smooth the surface (see, for example, Patent Documents 1 to 3). Furthermore, an ultrafine fiber raised surface is formed on the surface of the fiber entangled body, a fiber solvent or swelling agent is applied, the fibers are joined by hot pressing to smooth the surface, and a coating layer of a polymer elastic body is provided on the surface. A method for producing a leather-like sheet is also known. Patent Document 4 proposes a method of forming a surface while directly bonding a polyurethane nonwoven fabric to a base fabric.
Furthermore, Patent Document 5 proposes a leather-like sheet that is excellent in volume and air permeability by laminating a hot melt nonwoven fabric layer on a base material layer and providing a colored layer thereon.

Japanese Patent Publication No. 48-535 Japanese Patent Publication No. 48-536 Japanese Patent Publication No. 48-537 Japanese Patent Laid-Open No. 10-8382 JP 2008-63674 A

However, as in the conventionally proposed method, a breathable porous layer formed by a wet coagulation method or a dry coagulation method is added to the surface of the fiber layer by adding a foaming agent, an additive, a coagulation regulator, etc. The sheet obtained by this method is not satisfactory in terms of air permeability. In addition, in this method, the silver surface also has problems such as strong rubber rebound and poor surface wrinkling. In the case of a method of making a hole in the surface coating layer with a laser or the like, although the air permeability is satisfactory, the appearance is not high-class.
Further, as in Patent Documents 1 to 3 and the like, in the case of a method of forming a silver surface by melting and smoothing the fibers and the polymer elastic body constituting the fibrous sheet by hot melting or a solvent, Although satisfactory in terms of moisture permeability, the surface becomes hard, lacking in solidity close to that of natural leather, and glossy unevenness in appearance occurs, resulting in lack of luxury.
Further, as in Patent Document 4, in the method of making a surface while directly melting a polyurethane non-woven fabric into a base fabric, a high-quality appearance without uneven gloss is achieved by slowing the surface forming speed during production, Although a leather-like sheet with good air permeability can be obtained, since the polyurethane nonwoven fabric is bonded to the base fabric while being melted with heat, the melted polyurethane nonwoven fabric does not necessarily adhere to the base fabric. It is necessary to be fused at high temperature and / or high pressure in order to develop sufficient adhesion, and gloss unevenness is likely to occur due to this effect. There was also variation depending on the sampling position of the measurement sample. Further, when the polyurethane content of the base layer is low, this phenomenon becomes more remarkable, which is not preferable.
Also, in the case of laminating a hot melt nonwoven fabric layer as in Patent Document 5, when a hot melt nonwoven fabric that has been similarly heat fused is fused to the base fabric, it is simultaneously fused to the base fabric (thermal embossing). It is easy to be fused to a device etc., and it is difficult to manufacture stably.
Furthermore, hot melt nonwoven fabrics usually have a large fiber diameter and uneven formation, so if this layer is not thickened, sufficient smoothness and luxury on the silver surface cannot be obtained, while sufficient smoothness is obtained. For this reason, when the basis weight of this layer is increased and the layer is thickened, the obtained silver-finished leather-like sheet has a hard texture.

As a result of intensive studies on a leather-like sheet having a high-quality appearance and a closeness close to that of natural leather, the present inventors have found that a substrate comprising a fiber-entangled nonwoven fabric and a polymer elastic body contained therein It has been found that the above-mentioned problems can be solved by laminating a polyurethane nonwoven fabric on at least one surface of the layer with a heat-adhesive resin and integrating the laminate with the base layer.
That is, the present invention
(1) A silver surface layer in which a polyurethane nonwoven fabric is melted via a heat-adhesive resin layer is laminated on at least one surface of a substrate layer having a fiber-entangled nonwoven fabric, and silver comprising the substrate layer and the polyurethane nonwoven fabric. A leather-like sheet, wherein the peel strength with the face layer is 30 N / 2.5 cm or more,
(2) The leather-like sheet according to (1), wherein the polyurethane nonwoven fabric has a basis weight of 15 to 125 g / m ² .
(3) The leather-like sheet according to (1) or (2), wherein the heat-adhesive resin is a moisture-curable hot melt polyurethane,
(4) The leather-like sheet according to any one of (1) to (3), wherein the heat-adhesive resin layer is a heat-adhesive sheet having a basis weight of 3 to 40 g / m ² .
(5) The leather-like sheet according to (4), wherein the thermal adhesive sheet is made of a polyurethane continuous fiber nonwoven fabric,
(6) The leather-like sheet according to any one of (1) to (5), wherein the base layer is an ultra-fine long-fiber nonwoven fabric and 0 to 20% by mass of a polyurethane resin is contained therein,
(7) A method for producing a leather-like sheet obtained by laminating and integrating a polyurethane nonwoven fabric on at least one surface of a base layer, wherein the softening temperature is 20 ° C. or more lower than the softening temperature of the polyurethane resin constituting the polyurethane nonwoven fabric. A leather comprising: a heat-adhesive resin having a base layer and a layer made of the polyurethane non-woven fabric, and softening and melting the heat-adhesive resin so that the base layer and the layer made of the polyurethane non-woven fabric are laminated and integrated. And (8) the method for producing a leather-like sheet according to (7) above, wherein the laminate is integrated at a temperature equal to or higher than the softening temperature of the polyurethane nonwoven fabric after temporary lamination in the vicinity of the softening temperature of the thermal adhesive resin. ,
I will provide a.

  The leather-like sheet obtained in the present invention has a silver surface composed of a polyurethane nonwoven fabric fusion layer and has a feeling of unity between the silver surface and the underlying substrate layer, which is practically sufficient. Leather-like sheet having excellent peel strength. Furthermore, it is a leather-like sheet that has excellent air permeability and moisture permeability, and has a particularly excellent appearance without uneven gloss. Therefore, the leather-like sheet of the present invention has an effect that it can be used for men's shoes, sports shoes, general shoes, etc., particularly as a silvered leather-like sheet.

  Hereinafter, the present invention will be described in detail. In the present invention, a silver surface layer obtained by melting a polyurethane nonwoven fabric via a heat-adhesive resin layer is laminated on at least one surface of a substrate layer having a fiber-entangled nonwoven fabric, and the substrate layer and the polyurethane nonwoven fabric are formed. A leather-like sheet having a peel strength of 30 N / 2.5 cm or more with respect to the silver surface layer.

(Fiber entangled nonwoven fabric of base layer)
Examples of the fibers constituting the fiber-entangled nonwoven fabric of the base layer constituting the present invention (hereinafter sometimes referred to as “web-entangled sheet”) are at least 2 from the viewpoint of the flexibility of the obtained leather-like sheet. Examples thereof include ultrafine fiber-generating fibers made of various types of polymers. Ultrafine fiber generation type fiber is an extractable fiber that has a sea-island structure in cross section, or sea components are fibrillated into island components by dissolving or decomposing with water, solvent, or a decomposing agent such as sodium hydroxide. This is a collective term for split fibers or the like that fibrillate into ultrafine fibers made of each polymer. When flexibility is not particularly required, it may of course be composed of fibers having a normal thickness, or may be a mixture of the above ultrafine fiber-generating fibers and normal fibers.

  Examples of the polymer constituting the ultrafine fiber used for the fiber entangled nonwoven fabric of the base layer include polyamides that can be melt-spun such as 6-nylon and 66-nylon, polyethylene terephthalate, polybutylene phthalate, isophthalic acid-modified polyester, Examples thereof include at least one polymer selected from melt-spinnable polyesters such as cationic dyeable modified polyethylene terephthalate and polyolefins typified by polypropylene. In addition, as the component extracted or decomposed and removed by the extractable fiber, the solubility or decomposability with respect to water, a solvent or a decomposing agent is different from that of the ultrafine fiber component, and the solubility or decomposability with respect to water or a specific solvent or decomposing agent is different. Is a polymer that is higher than the ultrafine fiber component and has a lower melt viscosity or lower surface tension than the ultrafine fiber component under spinning conditions, such as polyvinyl alcohol, olefin-modified polyvinyl alcohol, polyethylene, polystyrene, polyethylene propylene. It is at least one polymer selected from polymers such as copolymers and modified polyesters. The volume ratio of the sea component to the island component of this ultrafine fiber-generating fiber is 1: 2 to 2: 1, and the preferred fineness after extracting the sea component is 0.01 in terms of texture and fulfillment. A range of ~ 0.0001 dtex is good.

(Manufacture of fiber entangled nonwoven fabric and stabilization of form)
Ultrafine fiber-generating fibers are collected as short fibers having a length of 20 to 75 mm and then made into a short fiber web by the card method, or after making into a long fiber web at the same time as spinning by a direct method such as the spunbond method. Or entangled with a high-speed fluid to obtain a fiber-entangled nonwoven fabric. Next, in this fiber-entangled nonwoven fabric, it is necessary to ensure the necessary strength and stability while maintaining the flexibility as much as possible. The method is to fix the fiber while maintaining the flexibility. The polymer elastic solution may be impregnated as described above, and as long as the necessary strength and stability can be ensured by sufficiently promoting the fiber entanglement due to the shrinkage of the nonwoven fabric as described later, the polymer elasticity is not necessarily required. There is no need to impregnate body solution.

  When impregnating the polymer elastic body solution, the fiber-entangled nonwoven fabric may be subjected to a surface smoothing treatment by a method such as hot pressing prior to the impregnation treatment. In addition, the fiber-entangled nonwoven fabric surface is heated and pressed between the constituent fibers in order to prevent shape breakage of the fiber-entangled nonwoven fabric that is likely to occur during the subsequent impregnation / coagulation of the polymer elastic body fluid and the extraction process of the fiber-constituting polymer A method of partially fusing or a method of impregnating a fiber-entangled nonwoven fabric with a water-soluble resin typified by polyvinyl alcohol and gluing and fixing the fibers may be used. Furthermore, when a resin that can be easily heat-shrinked, such as a modified polyester, is used as the fiber component, a high fiber density nonwoven fabric having stronger fiber entanglement can be obtained by developing heat shrinkage with hot water or the like. Is possible. The thickness of the fiber-entangled nonwoven fabric thus formed is preferably 1.0 to 3.0 mm.

The fiber entangled nonwoven fabric can be improved in the fiber density and the degree of entanglement by heat shrinking the fiber entangled nonwoven fabric because the fibers of the fiber entangled nonwoven fabric bind to each other. Shape stability can be improved, and when finished into a leather-like sheet, a sense of fulfillment is expressed, making it more like natural leather.
In this heat shrinking step, when the fiber-entangled nonwoven fabric containing long fibers is thermally shrunk, the fiber-entangled nonwoven fabric is greatly shrunk compared to the case where the fiber-entangled nonwoven fabric containing short fibers is thermally shrunk. As a result, the fiber density of the ultrafine single fibers is particularly high. The heat shrinkage treatment condition is not particularly limited as long as it is a temperature at which sufficient shrinkage can be obtained, and may be appropriately set according to the shrinkage treatment method to be employed, the processing amount of the treatment object, and the like. For example, when shrinkage treatment is performed by introducing into warm water, the shrinkage treatment is preferably performed at any temperature within a temperature range of 70 to 150 ° C.
Also, dry heat shrinkage is preferably employed, but wet heat shrinkage treatment is more preferred, and the wet heat shrinkage treatment method is preferably performed by steam heating. As steam heating conditions, it is preferable to heat-treat for 60 to 600 seconds under conditions of an ambient temperature of 60 to 100 ° C. and a relative humidity of 40 to 100% RH, more preferably 70 to 100% RH. Such heating conditions are preferable because the fiber-entangled nonwoven fabric can be shrunk at a high shrinkage rate. In addition, when a polyvinyl alcohol-based resin is used as a constituent component of the sea-island type composite fiber, if the relative humidity is too low, the moisture in contact with the fiber tends to dry quickly and the shrinkage tends to be insufficient. .
The fiber-entangled nonwoven fabric subjected to the wet heat shrinkage treatment in this way may further increase the fiber density by heating or pressing at a temperature equal to or higher than the heat deformation temperature of the ultrafine fiber-generating fiber.

By securing sufficient fiber entanglement and ensuring sufficient fiber stability by ensuring high fiber density, it can be used as a base layer of the leather-like sheet of the present invention without providing a polymer elastic body later. As a result, when it is finished into a leather-like sheet, it gives a sense of fulfillment and can be made closer to natural leather.
And by securing a high fiber density, the adhesion between the polyurethane nonwoven fabric and the fiber-entangled nonwoven fabric constituting the base layer is lowered as the application of the polymer elastic body is lowered. However, in this invention, even if it is a base layer which consists of a long fiber entangled nonwoven fabric which can ensure a high fiber density, it is possible to improve adhesiveness with a polyurethane nonwoven fabric through a heat adhesive resin layer. In particular, in an arbitrary cross section parallel to the thickness direction of the fiber-entangled nonwoven fabric, a dense structure such that the cross-section of the ultra-long elongated fiber bundle is present in the range of 1500 to 3000 pieces / mm ² , In any cross section parallel to the thickness direction, when the gap size between the ultra fine fiber bundles is 70 μm or less, or at least in any cross section parallel to the thickness direction of the fiber entangled nonwoven fabric, the average gap between the ultra fine fiber bundles A particularly remarkable effect is obtained in a leather-like sheet substrate having a dense fiber structure with a size in the range of 10 to 40 μm.
As the change in the basis weight of the fiber-entangled nonwoven fabric in the wet heat shrinkage treatment step, it is 1.1 times (mass ratio) or more, further 1.3 times or more as compared with the basis weight before the shrinkage treatment, and 2.0. It is preferable that it is 2 times or less, and further 1.6 times or less.

(Impregnation of polymer elastic body into fiber-entangled nonwoven fabric)
In addition, for the purpose of improving the shape stability of the fiber-entangled nonwoven fabric, before and / or after performing the ultrafine fiber treatment of the fiber-entangled nonwoven fabric, if necessary, impregnated with a polymer elastic body fluid, A dense foamed sponge may be formed by dipping in a liquid containing a non-solvent and wet coagulating. Alternatively, the shape stability may be improved by impregnating the fiber-entangled nonwoven fabric with an aqueous liquid of a polymer elastic body, followed by thermal gelation and dry coagulation.

  Examples of the method of impregnating the fiber-entangled nonwoven fabric with the polymer elastic body include a method of impregnating a solution or dispersion of the polymer elastic body and coagulating it by a conventionally known dry method or wet method. As the impregnation method, after immersing the fiber-entangled nonwoven fabric in a bath filled with a solution or dispersion of a polymer elastic body, the treatment is squeezed once or a plurality of times with a press roll or the like so as to be in a predetermined impregnation state. The dip nip method is preferably used. As other methods, a bar coating method, a knife coating method, a roll coating method, a comma coating method, a spray coating method, or the like may be used.

Specific examples of the polymer elastic body in the present embodiment include polyurethane elastomers, acrylonitrile elastomers, olefin elastomers, polyester elastomers, polyamide elastomers, acrylic elastomers, and the like. Moreover, the polymer composition which mixed these may be sufficient. However, polyurethane is preferably used in view of flexibility, elastic recovery, sponge formation and the like.
Examples of the polymer elastic body impregnated here include at least one polymer diol selected from polyester diol, polyether diol, polycarbonate diol, polyester polyether diol, and the like having an average molecular weight of 500 to 3000, and 4,4′-. At least one diisocyanate compound selected from aromatic, alicyclic or aliphatic diisocyanates such as diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate and the like, and at least one kind having two or more active hydrogen atoms A low molecular weight compound having a molecular weight of 300 or less, such as ethylene glycol, propylene glycol, 1,4-butanediol, hexanediol, 3-methylpentanediol-1,5,1, Diols such as 4-cyclohexanediol and xylene glycol, diamine compounds such as ethylenediamine, propylenediamine, xylylenediamine, isophoronediamine, piperazine, phenylenediamine, and tolylenediamine, hydrazines and hydrazides such as adipic hydrazide and isophthalic acid dihydrazide A polyurethane obtained by reacting at least one selected from the above.

In particular, in order to achieve the object of the present invention, a polyurethane obtained by reacting a chain extender mainly composed of 1,4-butanediol or 3-methylpentanediol-1,5 at a predetermined molar ratio is preferable. is there.
The concentration of the polymer elastic body in the polymer elastic body fluid is preferably 10 to 50% by mass and the Young's modulus is preferably in the range of 10 to 150 N / mm ² . The polyurethane preferably has a molar ratio of the polymer diol and the low molecular weight compound in the range of 1: 1 to 1: 7.

A liquid that acts as a solvent or a decomposing agent for the sea component and non-solvent for the island component of the polymer elastic body and the ultrafine fiber generating fiber after the fiber entangled nonwoven fabric contains the polymer elastic body. The ultrafine fiber generation type fiber is transformed into an ultrafine fiber bundle by treating with the above, and a sheet made of an ultrafine fiber entangled nonwoven fabric and a polymer elastic body is used as the base layer of the leather-like sheet of the present invention. Of course, prior to the inclusion of the polymer elastic body, a base layer may be formed by using a method of transforming ultrafine fiber-generating fibers into ultrafine fiber bundles.
And in the case of containing the polymer elastic body in this way, the content ratio to the ultrafine fiber entangled nonwoven fabric is not particularly limited as long as it achieves the purpose as the leather-like sheet of the present invention, but preferably Is not more than 50% by mass, more preferably not more than 30% by mass, still more preferably not more than 20% by mass, and most preferably not more than 15% by mass in terms of having a solid texture and peel strength comparable to natural leather. If the elastic body content exceeds 50% by mass, the resulting leather-like sheet tends to be hard, which is not preferable.

(Layer made of polyurethane nonwoven fabric)
In the present invention, a layer made of a polyurethane nonwoven fabric laminated on at least one surface of a base layer via a heat-adhesive resin constitutes a surface layer (hereinafter sometimes referred to as a “silver surface layer”), and is a polyurethane. It consists of resin, and the fabric weight is 15-125 g / m < ² >, The said polyurethane nonwoven fabric is heated and pressurized, and is formed into a film, and forms a silver surface layer. The filmed layer, that is, the silver surface layer, preferably retains fine pores. In order to maintain such fine pores, it is preferable that the layer made of the polyurethane nonwoven fabric is composed of a nonwoven fabric made of ultrafine polyurethane fibers. By constituting with a nonwoven fabric made of such an ultra-fine polyurethane fiber, the basic part of the excellent performance of the present invention described above can be obtained.

Examples of the polyurethane component constituting the polyurethane nonwoven fabric of the present invention include low molecular diols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and 3-methylpentane. Polyester glycol obtained by condensation polymerization with at least one selected from diol-1,5, etc., polyether glycol such as polyethylene ether glycol, polypropylene ether glycol, polytetramethylene ether glycol, polyhexamethylene glycol, polycaprolactone glycol At least one polymer diol selected from polylactone glycols such as polyvalerolactone glycol, and having a mean molecular weight of 500 to 3000 It is a polyurethane to a segment. In particular, polyurethane using a polyester diol having an average molecular weight of 700 to 3000 obtained by condensation polymerization of a diol mainly composed of 3-methylpentanediol-1,5 and a dicarboxylic acid is melt moldability, solvent stability, and hydrolysis resistance. gender, weather resistance, flexibility, is suitable in terms of flexibility, in particular have the following fine pore diameter 300 [mu] m 100 / cm ² or more, and at least a portion of the micropores bridges of polyurethane fibers This is preferable in that a silver surface layer having a structure is easily formed.

The organic Jiishishianeto reacted with the polymer diol, such as 4,4 '- diphenylmethane diisocyanate, tolylene diisocyanate, phenylene diisocyanate, aromatic diisocyanates such as xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated xylene diisocyanate In combination with at least one selected from aliphatic or alicyclic diisocyanates, etc., or an organic polyisocyanate having 3 or more isocyanate groups such as organic triisocyanate within a range not impairing melt spinnability or melt moldability May be.

  As the chain extender, a compound having two active hydrogen atoms and a molecular weight of 300 or less, for example, ethylene glycol, propylene glycol, 1,4-butanediol, hexanediol, 3-methylpentanediol-1,5,1,4 -Diols such as cyclohexanediol and xylene glycol, diamines such as ethylenediamine, propylenediamine, xylylenediamine, isophoronediamine, piperazine, phenylenediamine, tolylenediamine, hydrazines or hydrazides such as adipic hydrazide and isophthalic acid dihydrazide, etc. And at least one selected from. Particularly preferred is a polyurethane using a chain extender mainly composed of 1,4-butanediol or 3-methylpentanediol-1,5. The molar ratio of the polymer diol to the chain extender can be freely changed depending on the physical properties of the nonwoven fabric, but is preferably about 1: 2 to 7.

When the basis weight of the layer made of the polyurethane nonwoven fabric forming the surface layer of the leather-like sheet of the present invention is less than 15 g / m ² , the base layer is prepared by melting a thermoadhesive resin described later at the time of bonding to the base layer. When bonding a layer made of ultrafine fiber polyurethane nonwoven fabric, the melted heat-adhesive resin passes through the fiber voids of the layer made of ultrafine fiber polyurethane nonwoven fabric and flows out to the surface, and the surface is rough and has a tactile silver surface Or the appearance such as smoothness of the silver surface is deteriorated. On the other hand, if it exceeds 125 g / m ² , the heat-adhesive resin may not be sufficiently heated, and the balance between the silver surface layer and the substrate layer tends to decrease, and the texture tends to decrease. Furthermore, after heat sealing, the diameter of the micropores is reduced, or the micropores are blocked and air permeability tends to be lowered, which is not preferable. Nonwoven fabric made of ultrafine polyurethane fibers is produced by a method of entanglement of polyurethane fibers produced by a normal spinning method to make a nonwoven fabric, or a method of making a nonwoven fabric simultaneously with spinning, such as a spunbond method or a melt blown method. Things may be used. In particular, the non-woven fabric obtained using the melt blown method has a fine constituent fiber, a range that can be referred to as a so-called ultrafine fiber, and a silver surface that is more luxurious due to the reason that the fiber direction is random and closer to natural leather. This is preferable because a layer is formed.
In the present invention, the ultrafine polyurethane fiber refers to a fiber having an average fiber diameter of 10 μm or less.
Here, the average fiber diameter of the single fiber is an average value obtained by observing the surface of the ultrafine polyurethane fiber nonwoven fabric with an electron micrograph and measuring the fiber diameters at arbitrary 10 locations.

(Thermal adhesive resin layer)
Next, the heat-adhesive resin used for heat-sealing the base layer of the leather-like sheet of the present invention and the layer made of polyurethane nonwoven fabric is a thermoplastic having the ability to adhere both layers when it is once melted and solidified. Any resin may be used, and a resin generally called a thermoadhesive resin is preferable. More preferably, the resin type is not particularly limited as long as the resin has a melting point of about 80 to 160 ° C. For example, vinyl acetate, polyvinyl alcohol, polyvinyl acetal, vinyl chloride, acrylic, polyolefin (polyethylene), polyester, polyamide (nylon), polystyrene, polyurethane, various thermoplastics, or urea Any of cross-linking type resins such as melamine, phenol, resorcinol, epoxy, polyester, and polyurethane can be used. Moreover, when it is desired to develop stronger adhesion, a cross-linked resin may be used.

These heat-adhesive resins preferably suitably penetrate into both the base layer and the polyurethane non-woven fabric in order to maintain good adhesion strength and flexibility after adhesion. . Therefore, it is preferable that the heat-adhesive resin used in the present invention is in a predetermined range in the fluidity at the time of melting. That is, in the melt flow rate (MFR) of the resin, the value is preferably in the range of 1 to 200. If this value is too low, bonding at a higher temperature is required so that the resin can flow easily during bonding, and the layer made of the base layer or polyurethane nonwoven fabric may be deteriorated by heat.
On the other hand, if the fluidity is too high, it will easily flow into the fiber gap of the base layer or the layer made of polyurethane nonwoven fabric, so it is necessary to apply a large amount of adhesive. Since it becomes hard and closes the fiber, it becomes difficult to ensure air permeability and moisture permeability.
In the present invention, the peel strength between the layer made of polyurethane nonwoven fabric (silver surface layer ) and the base layer must be 30 N / 2.5 cm or more in the measurement method described later. When the peel strength is 30 N / 2.5 cm, in practical use as a silvered leather-like sheet, it is possible to almost avoid the problem that the polyurethane nonwoven fabric layer on the surface, that is, the silver surface layer peels from the base layer. And since it is suitable for men's shoes use that it is 50N / 2.5cm or more, it is suitable for sports shoes use etc. which can be adapted to severe conditions from 100N / 2.5cm or more. preferable.

As the heat-adhesive resin of the present invention, if the surface polyurethane nonwoven fabric and the fiber or resin forming the base layer are contained, it only needs to have an affinity with this resin. A urethane-based thermoadhesive resin having the following adhesiveness is preferred.
Furthermore, a crosslinked type such as a moisture curable polyurethane resin is more preferable because high heat resistance can be exhibited. As the component constituting the polyurethane resin, the same components as those constituting the above-described polyurethane fiber can be used, but the average molecular weight of each component is changed, the average degree of polymerization is reduced, or the polyurethane fiber is constituted. By selecting a component different from the component to be selected, a resin having a softening point lower by 20 ° C. or more than the polyurethane resin constituting the polyurethane nonwoven fabric is selected.

The method or form of supplying these adhesive resins between the base layer and the polyurethane nonwoven fabric layer is not particularly limited as long as the heat adhesive resin can be uniformly distributed in any layer. For example, a powdery resin may be sprayed, a liquid heat-adhesive resin or a heat-adhesive resin dissolved in a solvent may be applied by gravure, or the heat-adhesive resin may be applied in a film or non-woven fabric. You may laminate | stack the heat bonding sheet | seat of 3-40 g / m < ² > of fabric weights formed by developing in the shape. In order to ensure a higher level of flexibility, breathability, and moisture permeability in the leather-like sheet after lamination, a polyurethane continuous fiber nonwoven fabric type developed in a nonwoven fabric shape is more preferable. When the basis weight of the thermal adhesive resin layer is 3 to 40 g / m ² , the peel strength between the base layer and the polyurethane nonwoven fabric layer can be maintained within a predetermined range, and flexibility, breathability and moisture permeability can be secured.

Furthermore, when using a non-woven fabric made of a continuous linear body of heat-adhesive resin as the heat-adhesive resin layer, so-called polyurethane continuous fiber non-woven fabric, it is preferable to have a denser and more uniform structure with less fiber voids. . In the present invention, when the air permeability and the average fiber diameter are used as factors indicating the small voids and uniformity, the Frazier method may have a range of 100 to 600 cm ³ / cm ² / sec and an average fiber diameter of 10 to 100 μm. preferable.

Nonwoven fabric made of continuous linear forms of these heat-adhesive resin, so-called polyurethane continuous fiber nonwoven fabric, as described above, preferably has a basis weight of 5 to 40 g / m ^2. If the basis weight is less than 5 g / m ² , it is difficult to uniformly bond the layer made of the polyurethane nonwoven fabric on the surface and the substrate layer with sufficient adhesive strength, which is not preferable. On the other hand, if it is 40 g / m ² or more, a sufficient adhesive force can be secured, but the texture after adhesion becomes too hard and the texture does not have a high-class feeling.

  The polyurethane continuous fiber nonwoven fabric of the heat-adhesive resin is a method of entanglement of polyurethane fibers produced by a normal spinning method to make a nonwoven fabric, or a method of making a nonwoven fabric simultaneously with spinning, such as a spunbond method or a melt blown method. Any of those manufactured by the method may be used. Especially if the non-woven fabric obtained using the melt blown method has a thin constituent fiber, the fiber direction is random, and the fiber diameter is not constant and has a certain distribution, etc. Since a high-quality silver surface layer is formed, it is preferable.

(Leather-like sheet manufacturing method)
The method for producing a leather-like sheet of the present invention in which a layer made of polyurethane non-woven fabric and a base layer are bonded using a heat-adhesive resin and laminated and integrated ensures sufficient flexibility for the leather-like sheet obtained by bonding. However, it is possible to express a sensitivity closer to that of natural leather. In addition, when a method to reduce the amount of polymer elastic body contained in the base layer is selected as a method to ensure the fullness, flexibility and breathability of natural leather and to give the same sensitivity as natural leather It is particularly effective for forming a silver surface layer made of a polyurethane nonwoven fabric with necessary and sufficient adhesive strength in a state where flexibility is ensured for such a base layer.

In the method of integrating the substrate layer and the polyurethane nonwoven fabric layer in the present invention, any method can be used as long as a heat-adhesive resin layer is disposed between the two by the method described above and then heat-bonded. It is not particularly limited. However, as a method of more easily and stably integrating these three layers and ensuring a flexible and uniform lamination, a non-woven fabric made of a heat-adhesive resin developed in a continuous linear form, so-called polyurethane When the continuous surface nonwoven fabric is used, the random surface irregularities of the polyurethane nonwoven fabric layer and the random surface irregularities of the nonwoven fabric made of the heat-adhesive resin developed in a continuous linear pattern mesh with each other so that the nonwoven fabric is thermocompression bonded. It is preferable in that the adhesive force is improved.
Also in the order of lamination, as described above, the polyurethane continuous fiber nonwoven fabric of heat-adhesive resin may be arranged in the center and heat and pressure may be applied to bond the three layers simultaneously. May be adhered to the base layer after adhering to the layer made of the polyurethane nonwoven fabric constituting the silver surface layer, and conversely, after adhering the polyurethane continuous fiber nonwoven fabric of the heat-adhesive resin to the base layer, the silver surface layer It may be bonded and integrated with a layer made of a polyurethane nonwoven fabric constituting.

Here, as a method of laminating these three layers, the nonwoven fabric composed of a continuous linear body of the thermal adhesive resin at the center is not unevenly distributed locally, and is almost uniformly developed while maintaining its form. The method is not particularly limited as long as it can be bonded in such a state.
Specifically, a hot press using hot embossing is preferably used. In this case, the pressing temperature and pressure are not particularly limited, but it is necessary that the nonwoven fabric composed of the continuous linear body of the heat-adhesive resin at the center melts uniformly and contributes efficiently to the adhesion of the three layers. Therefore, it is preferable to use a roll of flat or fine shallow wrinkles (such as satin).
At this time, it is necessary to arrange so that at least the side of the layer made of the polyurethane nonwoven fabric that becomes the surface layer (silver surface layer) comes to the hot embossing roll side. And it is preferable to laminate | stack by heating and pressurizing with the pressure of 0.1-1 Mpa at the temperature 0-50 degreeC higher than the softening point of the continuous linear body of this thermoadhesive resin.

  On the other hand, when a non-woven fabric composed of a continuous linear body of a heat-adhesive resin is first bonded to a polyurethane non-woven fabric or a base layer and then double-layered, and then bonded to three layers, the first two-layer method is Although it is not particularly limited as long as adhesion is performed in a state having a form of a polyurethane continuous fiber nonwoven fabric of a heat-adhesive resin, preferably on a layer made of a polyurethane nonwoven fabric or a base layer that becomes a surface layer (silver surface layer), Examples include a method in which a heat-adhesive resin is melted and contact-developed and bonded while forming a molten or semi-molten continuous linear body on these surfaces, that is, a hot melt spray method or a melt blow method. . In particular, the melt-blowing method is particularly preferable because the force of hot air blowing the linear body is strong, and the linear body can be formed with sufficiently thin fibers and can be more uniformly developed.

The laminated body thus integrated is further laminated and integrated at a temperature equal to or higher than the softening temperature of the polyurethane nonwoven fabric that becomes the surface layer (silver surface layer). A polyurethane non-woven fabric can be made into a film and finished into a smooth silver surface.
Furthermore, this laminated integration treatment allows the heat-adhesive resin constituting the polyurethane continuous fiber nonwoven fabric of the heat-adhesive resin to penetrate into the base layer and the layer made of the ultrafine polyurethane nonwoven fabric and to develop sufficient adhesive force. It is valid.

As a method for achieving these, the hot embossing method is preferably used.
The pressing temperature and pressure at this time are not particularly limited, but are usually 0 to 80 ° C. higher than the softening point of the resin constituting the polyurethane continuous fiber nonwoven fabric of the thermoadhesive resin and / or the pressure 1 It is preferable to stack and integrate at 10 MPa. If bonding is performed at a low temperature with respect to the softening point, the silver layer may not be formed, or the appearance of the silver surface may be deteriorated and adhesion failure may also occur. On the other hand, at a temperature higher than 80 ° C. from the softening point, the fine pores of the polyurethane continuous fiber nonwoven fabric of the heat-adhesive resin may be crushed too much, resulting in poor air permeability. Or the fluidity | liquidity of resin which comprises a polyurethane nonwoven fabric increases too much, and it becomes impossible to ensure surface smoothness by adhering to a heat | fever embossing roll or flowing into a base layer.
Next, as the pressure for lamination (bonding), adhesion may be poor when lamination is performed at a pressure lower than 1 MPa, and the texture tends to be hard at pressures higher than 10 MPa. In the present invention, the softening point was defined as the temperature at which it was determined that the resin began to melt visually using a melting point measurement device (YANACO MP-500V).

Thus obtained surface layer (grain layer) is preferably has the following fine pore diameter 300 [mu] m 100 / cm ² or more. A polyurethane nonwoven fabric is formed into a film by heating and pressurization, but micropores remain in the film. When the diameter of the micropores exceeds 300 μm, uneven glossiness is caused and the appearance is deteriorated. Therefore, it is necessary that the diameter is 300 μm or less, and preferably 100 μm or less. Further, the number of micropores is 100 / cm ² or more, preferably 300 / cm ² or more. By satisfying this number, the air permeability is improved. In the present invention, pores having a diameter exceeding 300 μm may exist if the amount is small. The micropore diameter is defined as the diameter of a circle having the same area as the surface area of the hole.

  Furthermore, it is preferable that at least some of the micropores have a polyurethane fiber bridging structure. The ratio of the bridge structure is not particularly limited, but if it is 10% or more of all the fine holes, it tends to eliminate uneven gloss. Preferably more than 30% has a bridge structure. The micropores having a bridge structure in the present invention are an arbitrary selection of the surface of the sheet, and an electron micrograph is observed. In the micropores, one or more fibers having a fiber diameter of 3 μm or more are bridged. It exists in such a state. Although it is not always clear why a polyurethane fiber bridge structure is effective in resolving uneven luster, it is blocked by the bridge fiber when light incident on the micropores is reflected. Therefore, it is predicted that it is difficult to emit from the fine holes or diffused.

  Moreover, as for the thickness formed from the layer which consists of a polyurethane nonwoven fabric, ie, the thickness of a silver surface layer, 10-500 micrometers is preferable. If it is thinner than 10 μm, the abrasion resistance of the silver layer is not practically sufficient, and if it is thicker than 500 μm, a natural crease / texture cannot be obtained, impairing the sense of quality. The thickness of the silver surface layer referred to here is the average of the thicknesses obtained from an electron micrograph.

  In the production method of the present invention, it is necessary that the softening point of the continuous linear body of the heat-adhesive resin used for bonding is at least 20 ° C. lower than the softening point of the polyurethane constituting the polyurethane nonwoven fabric. Laminate lamination of the leather-like sheet is performed by heat-sealing, so that the polyurethane non-woven fibers that become the surface layer (silver surface layer) are added from the fusion-fixed state of the polyurethane continuous fiber non-woven fabric of the heat-adhesive resin. In addition, the adhesive area is increased, resulting in an increase in the adhesive force. In this case, in order to suppress the deterioration of the air permeability, the thermal adhesion of the polyurethane nonwoven fabric on the surface is It is suppressed to the extent necessary to obtain a high-quality silver surface layer, and is mainly based on a polyurethane continuous fiber nonwoven fabric of a heat-adhesive resin used for bonding. Therefore, when the difference in softening point is less than 20 ° C. or the softening point of the adhesive resin is higher, the adhesive strength is lowered, and in some cases, the sense of unity of the laminate is impaired, or the micropores of the polyurethane nonwoven fabric are blocked, Air permeability is reduced.

  The leather-like sheet thus obtained can be subjected to post-processing such as coloring. Regarding coloring, of course, dyes and pigments can be added in advance to the components constituting the leather-like sheet. When coloring is performed by post-processing, it can be colored with a colorant solution composition comprising a solvent, a resin and a colorant containing dimethylformamide in an amount of less than 10% by mass. On the other hand, if the dimethylformamide content is 10% by mass or more, fine pores on the surface are crushed and air permeability is impaired. Then, if necessary, finish processing such as embossing embossing, dyeing, softening treatment, fir treatment and the like can be carried out to finish a silvered leather-like sheet.

Next, embodiments of the present invention will be described with specific examples, but the present invention is not limited to these examples. In addition, unless otherwise indicated, the part and% in an Example are related to mass.
Moreover, the peeling strength of the layer (silver side) which consists of a polyurethane nonwoven fabric, and a base material layer, and the air permeability of the leather-like sheet | seat were measured with the following method, respectively.

[Peel Strength]: The test piece having a width of 2.5 cm and a length of 25 cm is bonded to a rubber plate having a thickness of about 4 mm with a urethane adhesive. The test piece is marked with 5 sections at intervals of 2 cm, then immersed in water for 10 minutes, taken out, and subjected to a peel test at a speed of 50 mm / min with a tensile tester. The lowest value of each section was read from the obtained chart, and the average value was converted to 1 cm width.

[Air permeability]: Measured by a method defined by A method of 6.27.2 of JIS L-1096.

[Number of sea-island fibers or ultrafine fibers in the cross section of the base layer of leather-like sheet, void size between ultrafine fiber bundles, average void size]
For an arbitrary cross section parallel to the thickness direction of the sample, using a scanning electron microscope (about 100 to 300 times), a continuous cross sectional area is formed so that the total observation area is about 0.3 to 0.5 mm ^2. Observed. In the observation field of view, the number of cross-sections judged to be substantially perpendicular to the length direction of the sea-island fiber or the ultrafine fiber bundle is counted, and the total number is divided by the observation area to be present per 1 mm ^2. The number of cross-sections of sea-island fibers or ultrafine fiber bundles was determined. Such observation was performed on at least five locations for one type of sample, and the smallest value was taken as the number density of the sample.
Next, in the same observation field, all regions other than the cross section of the ultrafine fiber bundle were regarded as voids, and the largest circle in contact with the cross section of the ultrafine fiber bundle was drawn, and the diameter of the circle was measured. However, when voids exist continuously in a wide range, a plurality of circles were drawn so that the circles did not overlap, and the circle with the maximum diameter was measured among the drawn circles. Except for the case where almost all the fiber bundles are in close contact with each other in the entire observation field, the voids in the portions where the fiber bundles are in close contact are excluded from the evaluation targets in the observation field. In addition, the term “existing in close contact” refers to a case in which they are close to each other to the extent equal to or less than the fiber diameter of the ultrafine fibers constituting the fiber bundle. In the diameter of the circle thus measured, the maximum value in the observation visual field was defined as the gap size between the ultrafine fiber bundles of the sample. In addition, the average void size between the microfiber bundles was obtained by arithmetically averaging 18 circular diameters measured at 20 voids randomly selected in the observation field and excluding the maximum and minimum values. It was.

Production Example 1
(Manufacture of base layer A)
As a base layer, using a staple fiber obtained by cutting a sea-island fiber having a fineness of 6 denier made of high-fluidity polyethylene (sea component) and 6-nylon (island component) to a fiber length of 51 mm, a dry fiber web is made. A laminated web was formed by the cross wrap method, and the nonwoven fabric having a basis weight of 300 g / m ^{2 was} obtained by fiber entanglement by the needle punch method and heat treatment. This nonwoven fabric was impregnated with a 20% dimethylformamide solution of polyester type polyurethane (the chain extender was 1,4 butanediol and the molar ratio of the polymer diol and the chain extender was 1: 4), and the urethane adhering to the surface was removed with a knife. Thereafter, the solution was solidified in an aqueous dimethylformamide solution. Next, the solvent dimethylformamide is removed by washing with hot water, and then the polyethylene in the fiber is dissolved and removed with hot toluene to obtain an average number of ultrafine fiber bundles of 1000 / bundle and an average fineness of 0.001 dtex 6-nylon ultrafine fibers. The fiber sheet (base layer A) which consists of 45 mass% of entangled nonwoven fabrics and porous polyurethane content was obtained.

Production Example 2 and Production Example 3
(Manufacture of base layer B and base layer C)
As sea component polymer, ethylene modified polyvinyl alcohol (ethylene unit content 8.5 mol%, polymerization degree 380, saponification degree 98.7 mol%), as island component polymer in Production Example 2, isophthalic acid modified polyethylene terephthalate (inherent Viscosity 0.59) was melted individually using polyethylene terephthalate (intrinsic viscosity 0.65) in Production Example 3. The molten polymer can be combined with the sea component polymer in the cross section in a multi-spinning base in which a large number of nozzle holes are arranged in parallel to form a cross section in which 25 island component polymers having a uniform cross-sectional area are distributed in the sea component polymer. The island component polymer was supplied in a pressure balance so that the average area ratio of the island component polymer was sea component / island component = 25/75, and was discharged from the nozzle hole at a die temperature of 250 ° C.
The islands are pulled and thinned by an air jet / nozzle type suction device that adjusts the pressure of the airflow so that the average spinning speed is 3600 m / min, and sea-island fibers having an average cross-sectional area of 177 μm ² (about 2.4 dtex) are spun. , Continuously collected on the net. The amount of deposition was adjusted by adjusting the moving speed of the net, and was further pressed with an embossing roll kept at 80 ° C. at a linear pressure of 70 kg / cm to obtain a long fiber web having a basis weight of 30 g / m ² .

After embossing the surface of the long fiber web, spraying an oil agent mainly composed of a mineral oil-based slipping oil and mixing an antistatic agent, and then continuously folding the long fiber web using a cross wrapper device, A 14 layer laminar long fiber web. Subsequently, a three-dimensional entanglement treatment was performed by a needle punching method in which needle punching was applied to the layered long fiber web, thereby obtaining a nonwoven fabric structure in which the number density of sea-island fibers was 500 / mm ² . The conditions of needle punching are: needle A with needle count 40, pre-entanglement with the punch depth through which the barb penetrates in the thickness direction from both sides, then needle B with needle count 42 in total from both sides The number of punches was 1700 punches / cm ² .
Next, after uniformly spraying 18 ° C. water on both surfaces of this nonwoven fabric structure, a wet heat shrinkage treatment was performed under conditions such that it was immediately passed through an atmosphere at a temperature of 75 ° C. and a relative humidity of 95% over 4 minutes. went. Then, before drying the non-woven fabric structure, press it between metal rolls kept at 120 ° C. and dry it while compressing and smoothing the surface, and then introduce the entire non-woven fabric structure into an atmosphere at 120 ° C. and dry it. As a result, an extremely dense nonwoven fabric structure was obtained such that the number density of sea-island fibers was 1900 pieces / mm ² in a cross section parallel to the thickness direction at a basis weight of 1125 g / m ² .

The resulting nonwoven fabric structure was impregnated with an aqueous dispersion (solid content concentration 15%) of a polyurethane composition mainly composed of polycarbonate / ether-based polyurethane as a polymer elastic body fluid, and the polymer was in mass with respect to 100 mass of the nonwoven fabric structure. After pressing with a metal roll so that the liquid content of the elastic body fluid is 50, heat-coagulated by applying an infrared heater for 1 minute under the condition that the surface temperature of the nonwoven fabric structure is 80 ° C. The polyurethane composition was made to exist in the space | gap between sea-island type fibers by introduce | transducing into the atmosphere of 120 degreeC, drying the water | moisture content, and then immediately introducing into a 150 degreeC atmosphere and performing a curing process for 2 minutes. Next, the modified polyvinyl alcohol in the sea-island fiber is extracted and removed by treatment with hot water at 90 ° C. for 20 minutes in a liquid dyeing machine, and then introduced into an atmosphere at 120 ° C. to dry the moisture. About 10% by mass of the polyurethane composition is contained in the fiber-entangled nonwoven fabric composed of the acid-modified polyethylene terephthalate ultrafine fiber bundle, and the number density of the ultrafine fiber bundles in the cross section parallel to the thickness direction is 2500 / mm ^2. The gap size between the ultrafine fiber bundles is 52 μm, the average gap size is 35 μm, and the base layer for the leather-like sheet (base layer B) of the present invention and the ultrafine fiber bundles of polyethylene terephthalate having a thickness of about 1.4 mm. A base layer (base layer C) for a leather-like sheet of the present invention having a thickness of about 1.4 mm containing 10% by mass of a polyurethane composition was obtained inside the fiber-entangled nonwoven fabric.

Production Example 4
(Manufacture of polyurethane nonwoven fabric)
A molar ratio of poly-3methyl-1,5 pentyl adipate glycol having an average molecular weight of 1150, 4,4-diphenylmethane diisocyanate and 1,4-butanediol in a molar ratio of 1: 4: 3 (theoretical nitrogen content based on isocyanate is 4.63%) Then, polyurethane was polymerized by melt polymerization using a screw type kneading type polymerization machine. The polyurethane had a softening point of 172 ° C. The obtained polyurethane was extruded in a molten state from a die orifice heated to a temperature of 260 ° C. by a melt blow method, and at 25 m by high-speed air heated to 260 ° C. ejected from a slot on both sides at a pressure of 0.4 MPa. A nonwoven fabric A having an average basis weight of 25 g / m ² was obtained while making the resin extruded on the conveyor net running at a speed of / min. At this time, on the side opposite to the orifice of the conveyor net, the suction of the hot air blown out from the slot is sucked at a flow rate of three times or more to prevent disturbance of the fiber flow and to ensure the desired uniformity of the web to be manufactured. . The distance between the conveyor and the nozzle was 25 cm. The obtained nonwoven fabric was a random web of fine fibers having an average fiber diameter of 4.2 μm.

Production Example 5
(Manufacture of non-woven fabric made of thermal adhesive resin)
Using heat-adhesive resin E790MSJR (softening temperature 100 ° C.) manufactured by Japan Miractolan Co., Ltd., this was extruded from a die orifice heated to 260 ° C. by a melt blow method by an extruder, and at a pressure of 0.4 MPa from slots on both sides thereof Polyurethane continuous fiber non-woven fabric D having an average basis weight of 25 g / m ² while being spun into a conveyor net that travels at a speed of 25 m / min by high-speed air heated to 260 ° C. and spouted in, while making the resin extruded from the orifice into ultrafine fibers Got. At this time, on the side opposite to the orifice of the conveyor net, the suction of the air at a flow rate more than 3 times the hot air blown out from the slot prevents the fiber flow from being disturbed and the polyurethane continuous fiber (web) to be accumulated The desired uniformity was ensured. The distance between the conveyor and the nozzle was 35 cm.

Example 1
It was obtained in Production Example 4 such that the polyurethane continuous fiber nonwoven fabric D obtained in Production Example 5 was in the middle on the base layer A containing the 6-nylon ultrafine fiber entangled nonwoven fabric obtained in Production Example 1. A non-woven fabric A was overlaid, and a laminated sheet adhered at a press pressure of 0.196 MPa (2 kg / cm ² ) with a hot embossing roll having a surface textured pattern of 110 ° C. was obtained.
Thereafter, the surface temperature of the embossing roll is raised to 160 ° C., and the ultrafine polyurethane fibers in the polyurethane nonwoven fabric layer existing on the surface of the laminated sheet are melt-bonded to each other at a press pressure of 0.49 MPa (5 kg / cm ² ). Thus, a silver surface layer was formed to obtain a textured leather-like sheet with silver.
This silver-finished leather-like sheet had a high-grade leather-like appearance without uneven glossiness and air permeability of 0.9 cm ³ / cm ² / sec. On the surface, there were about 700 micropores / cm ² with an average diameter of 17 μm, and some micropores were bridged from the electron micrograph. The thickness of the silver surface layer (coating layer) was 34 μm. The peel strength of this product was 163 N / 2.5 cm.

Example 2
The continuous linear nonwoven fabric D obtained in Production Example 5 is sandwiched between the base layer B containing the ultrafine fiber entangled nonwoven fabric made of isophthalic acid-modified polyethylene terephthalate (inherent viscosity 0.59) obtained in Production Example 2. As described above, the non-woven fabric A obtained in Production Example 4 was superposed, and a laminated sheet adhered at a press pressure of 0.196 MPa (2 kg / cm ² ) with a hot embossing roll having a surface texture of 110 ° C. was obtained. .
Thereafter, the surface temperature of the embossing roll is raised to 160 ° C., and the ultrafine polyurethane fibers of the polyurethane nonwoven fabric are melt-bonded to each other at a press pressure of 0.49 Mpa (5 kg / cm ² ) to form a silver surface layer. A leather-like sheet was obtained. This silver-finished leather-like sheet had a high-grade leather-like appearance without uneven glossiness and air permeability of 1.3 cm ³ / cm ² / sec. There were about 1200 micropores / cm ² with an average diameter of 18 μm on the surface, and some micropores were bridged from the electron micrograph. The thickness of the silver surface layer (coating layer) was 43 μm. The peel strength of this product was 182 N / 2.5 cm.

Example 3
Polyethylene of Production Example 3 obtained in the same manner as in Production Example 2 except that polyethylene terephthalate (intrinsic viscosity 0.65) was used instead of isophthalic acid-modified polyethylene terephthalate as the island component thermoplastic resin in Production Example 2. A base layer C made of a terephthalate fiber entangled nonwoven fabric was obtained. On the base layer C obtained here, the nonwoven fabric A obtained in Production Example 4 is superimposed so that the polyurethane continuous fiber nonwoven fabric D obtained in Production Example 5 is sandwiched therebetween, and a surface textured pattern of 110 ° C. A laminated sheet adhered at 0.196 MPa (2 kg / cm ² ) with a hot embossing roll was obtained.
Thereafter, the surface temperature of the embossing roll was raised to 160 ° C., and the polyurethane nonwoven fabric was melt-bonded at a press pressure of 0.49 MPa (5 kg / cm ² ) to obtain a textured leather-like sheet with silver. This silver-finished leather-like sheet had a high-grade leather-like appearance without uneven glossiness and air permeability of 0.3 cm ³ / cm ² / sec. On the surface, there were about 950 micropores having an average diameter of 10 μm / cm ² , and about 30% of the micropores were bridged from the electron micrograph. The thickness of the silver layer (coating layer) was 53 μm. The peel strength was 148 N / 2.5 cm.

Example 4
As in Production Example 2, the nonwoven fabric structure after needle punching is immersed in hot water at a temperature of 75 ° C. for 5 seconds or more while almost no tension or frictional stress acts in either the length direction or the width direction. The shrinkage treatment is performed, and then the entire fiber-entangled nonwoven fabric structure is introduced into an atmosphere at 120 ° C. and dried to ensure a strong fiber-entangled state and to eliminate the form stabilization by impregnation with polyurethane resin. Thus obtained substrate layer D was obtained. On the sheet obtained here, the nonwoven fabric A obtained in Production Example 4 is superimposed so that the polyurethane continuous fiber nonwoven fabric D obtained in Production Example 5 is sandwiched therebetween, and the heat of the surface textured pattern at 110 ° C. A laminated sheet adhered with an embossing roll at a press pressure of 0.196 MPa (2 kg / cm ² ) was obtained.
Thereafter, the surface temperature of the embossing roll is raised to 160 ° C., and the ultrafine polyurethane fibers of the polyurethane nonwoven fabric existing on the surface of the laminated sheet are melt-bonded to each other at a press pressure of 0.49 MPa (5 kg / cm ² ). A face layer was formed to obtain a textured leather-like sheet with silver. This silver-finished leather-like sheet had a high-grade leather-like appearance without unevenness of luster and a solid texture like natural leather, and air permeability of 2.5 cm ³ / cm ² / sec. The surface had about 1800 micropores having an average diameter of 32 μm / cm ² , and some micropores were bridged from the electron micrograph. Moreover, the thickness of the silver surface layer (coating layer) was 53 μm. The peel strength of this product was 83 N / 2.5 cm.

Example 5
A polyurethane nonwoven fabric A obtained in Production Example 4 after spray-coating a moisture-curable polyurethane heat-adhesive resin on a base layer C obtained in Production Example 3 with a hot melt machine so as to have a basis weight of 15 g / m ^2. And a laminated sheet adhered at a press pressure of 0.196 MPa (2 kg / cm ² ) with a normal surface-like nip roll.
Thereafter, the surface temperature of the embossing roll was raised to 160 ° C., and the polyurethane nonwoven fabric was melt-bonded at a press pressure of 0.49 MPa (5 kg / cm ² ) to obtain a textured leather-like sheet with silver. This silver-finished leather-like sheet had a high-grade leather-like appearance without uneven glossiness and air permeability of 2.3 cm ³ / cm ² / sec. And the surface is present micropores of about 1,500 / cm ² in average diameter 21 [mu] m, from electron micrographs, crosslinking was observed at about 30% of the micropores. The thickness of the silver surface layer (coating layer) was 24 μm. The peel strength of this product was 107 N / 2.5 cm.

Comparative Example 1
10% dimethylformamide of polyurethane resin (SSTC-44: manufactured by Dainichi Seika Co., Ltd., softening point 110 ° C.) as an adhesive resin using a 150 mesh gravure roll on the fiber sheet (base layer A) obtained in Production Example 1. Immediately after application of the (hereinafter DMF) solution in the form of dots, the polyurethane nonwoven fabric A obtained in Production Example 4 is overlaid, bonded with a press roll (110 ° C., 0.196 MPa), dried and temporarily fixed. A sheet laminated with a polyurethane nonwoven fabric was obtained. Thereafter, the polyurethane nonwoven fabric A was melt-bonded with an embossing roll having a surface temperature of 160 ° C. at a press pressure of 0.49 Mpa (5 kg / cm ² ) to obtain a textured leather-like sheet with silver. This silver-finished leather-like sheet had a high-grade leather-like appearance without uneven glossiness and air permeability of 4.3 cm ³ / cm ² / sec. The surface had about 750 micropores having an average diameter of 12 μm / cm ² , and about 30% of micropores were bridged from the electron micrograph. The thickness of the silver surface layer was 22 μm. However, the peel strength of this product was 26 N / 2.5 cm, which was less than the practically required peel strength of 30 N / 2.5 cm.

Comparative Example 2
Laminated leather-like sheets were obtained by laminating in the same manner as in Comparative Example 1 except that the sheet (base layer C) obtained in Production Example 3 was used. The peel strength of the obtained leather-finished leather-like sheet was 24 N / 2.5 cm, which was insufficient in peel strength as in Comparative Example 1.

Comparative Example 3
A laminate-like leather-like sheet was obtained in the same manner as in Comparative Example 1 except that the sheet (base layer D) prepared so that the polyurethane contained was 20% by mass was used in Production Example 3. The peel strength of the obtained leather-finished leather-like sheet was 17 N / 2.5 cm, which was insufficient peel strength as in Comparative Example 1.

  The above Examples and Comparative Examples are shown together in Table 1.

  The leather-like sheet obtained in the present invention has a feeling of unity between the silver surface and the underlying substrate layer, and has a practically sufficient peel strength, and further has air permeability and moisture permeability. It is a leather-like sheet having an excellent appearance with no gloss unevenness, and can be used for men's shoes, sports shoes, general shoes and the like. Moreover, the method for producing a leather-like sheet of the present invention can be used as a method for stably producing a leather-like sheet having excellent air permeability and moisture permeability and having an extremely excellent appearance without particularly uneven gloss.

Claims (8)

  A silver surface layer in which a polyurethane nonwoven fabric is melted via a heat-adhesive resin layer is laminated on at least one surface of a substrate layer having a fiber-entangled nonwoven fabric, and the silver surface is composed of the substrate layer and the polyurethane nonwoven fabric. The leather-like sheet | seat characterized by the peeling strength with a layer being 30 N / 2.5cm or more. The leather-like sheet according to claim 1 polyurethane nonwoven fabric, comprising a basis weight of 15~125g / m ^2.   The leather-like sheet according to claim 1 or 2, wherein the heat-adhesive resin is a moisture-curable hot melt polyurethane. Heat-adhesive resin layer, the leather-like sheet according to any one of claims 1 to 3 is a thermal adhesive sheet having a basis weight 3~40g / m ^2.   The leather-like sheet according to claim 4, wherein the thermal bonding sheet is made of a polyurethane continuous fiber nonwoven fabric.   The leather-like sheet according to any one of claims 1 to 5, wherein the fiber-entangled nonwoven fabric of the base layer contains an ultra-thin fiber nonwoven fabric and 0 to 20% by mass of a polyurethane resin therein.   A method for producing a leather-like sheet obtained by laminating and integrating a polyurethane nonwoven fabric on at least one surface of a substrate layer, and having a softening temperature lower by 20 ° C. or more than a softening temperature of a polyurethane resin constituting the polyurethane nonwoven fabric A method for producing a leather-like sheet, characterized in that an adhesive resin is present between a base layer and the polyurethane nonwoven fabric, the thermal adhesive resin is softened and melted, and the base layer and the polyurethane nonwoven fabric are laminated and integrated.   The method for producing a leather-like sheet according to claim 7, wherein the leather-like sheet is temporarily laminated in the vicinity of the softening temperature of the heat-adhesive resin and then laminated and integrated at a temperature equal to or higher than the softening temperature of the polyurethane nonwoven fabric.