JPH0637750B2 - Leather-like sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention has a surface that is small in resilience and flexible, and feels slimy when touched by the hand, moisture permeability, surface strength, and destruction of porous structure. The present invention relates to a leather-like sheet having good strength and the like.

[Prior Art] Conventionally, in a leather-like sheet having a porous surface layer of a polymer mainly composed of polyurethane, there have been many proposals for improving the physical properties of the surface. In particular, with regard to the improvement of surface crease morphology, air permeability, moisture permeability, repulsion, etc., we have studied the raw materials used, manufacturing conditions, etc., mainly on the structure and configuration of the leather-like sheet. For example, from the aspect of the structure and structure of the leather-like sheet, the porous surface of the honeycomb structure having an average diameter of about 20 to 200 μm is polished so that most of the bubbles on the exposed surface are 10 μm except the skin (skin layer). As described above, a leather-like sheet for forming a polymer film layer on the surface and finishing the so-called silver surface is disclosed in JP-B-40-20273 and JP-B-47-386.
No. 23, Japanese Patent Publication No. 54-963. Furthermore, a polyurethane solution is applied to the surface of the surface layer having a porous structure having a large number of microholes having a pore size of 3 to 100 μm on the surface, and the microholes are shaped into fine pores and the surface has microholes. Leather-like seat
No. 345, Japanese Patent Publication No. 56-10346, and in Japanese Patent Publication No. 61-47522 a finishing method of applying a dispersion of polymer fine particles such as polyurethane to the surface having fine pores to finish.
Japanese Patent Publication Sho-Kakusho, which uses a composition prepared by dispersing a methacrylic acid ester polymer in a polyurethane solution as a finishing agent.
In Japanese Patent Publication No. 55-44111, it is proposed in Japanese Patent Publication No. 59-42109 to apply a polycyclic carboxylic acid having 11 or more carbon atoms or its ester in order to improve the texture of the surface.

[Problems to be Solved by the Invention] A conventional leather-like sheet has improved appearance performance, for example, folds and wrinkles are made to resemble natural leather, and drapeability is improved to obtain a solid appearance, and performance is improved. Is permeable
There was a direction of study to improve the moisture permeability. However, although the conventional leather-like sheet is flexible, it has a dry feel to the touch. Therefore, treatment with a softening agent, a plasticizer, or an oil agent for improving the texture is also performed in order to obtain a leather-like sheet with a soft feel and a soft texture, but only these treatment agents were used. In this case, it is not preferable to improve the tactile sensation only by the treatment agent, because the treatment agent may cause stickiness peculiar to the treatment agent or may have an unfavorable effect on the bleeding of the treatment agent or the polyurethane after a long time.

The present invention provides a leather-like sheet which is small in resilience and soft, feels touching to the hand, particularly feels slimy without feeling tackiness, and has good moisture permeability, surface strength and surface layer breaking strength. There is. Another object of the present invention is to provide a leather-like sheet having a surface and creases similar to those of leather, and having improved visual performance of feeling the feeling of pressure and softness.

[Means for Solving Problems] The present invention provides a skinless surface layer (2) having a porous chamber structure of polyurethane-I, wherein the organic diisocyanate constituting the fibrous base layer (1) and polyurethane is an organic diisocyanate containing an aromatic ring. ) And the organic diisocyanate constituting the polyurethane in the porous structure of at least the surface portion of the surface layer (2) is a polyurethane composed of an organic diisocyanate mainly composed of an aliphatic diisocyanate and / or an alicyclic diisocyanate- II is added, and the surface layer surface is a polyurethane coating film mainly composed of fine particle polyurethane, which is a leather-like sheet.

Further, the present invention comprises a fibrous substrate layer (1) and a porous skinless surface layer (2) of polyurethane-I in which the organic diisocyanate constituting the polyurethane is an aromatic ring-containing organic diisocyanate. Polyurethane-II composed of an organic diisocyanate in which an organic diisocyanate that constitutes polyurethane is composed of an aliphatic diisocyanate or / and an alicyclic diisocyanate as a main component is provided to the porous structure of at least the surface portion of (2), and the surface is A leather-like sheet characterized in that the surface of the layer is a coating film of a composition comprising polyurethane mainly composed of fine particle polyurethane and a polyoxyethylene-modified or glycerin-modified hardened oil.

That is, the present invention was obtained by coagulating a solution or dispersion of a polymer mainly composed of polyurethane-I, which is an organic diisocyanate having an aromatic ring as an organic diisocyanate which constitutes polyurethane on one surface of the fibrous substrate layer (1). Apparent density 0.
A porous sheet provided with a surface layer (2) having a porous structure of 25 to 0.48 g / cm ³ is treated on the surface of the surface layer to expose most of the internal pores of the surface layer, and then constitutes polyurethane. The organic diisocyanate is applied with a solution or dispersion of polyurethane-II composed of an organic diisocyanate mainly composed of an aliphatic diisocyanate and / or an alicyclic diisocyanate, the solvent or the dispersion is removed, and then embossing and / or A solution or dispersion of a polymer mainly composed of polyurethane-II is applied, and after removing the solvent or dispersant, or on the surface not subjected to embossing and / or polyurethane-II application, a colorant is optionally contained. Alternatively, a solution or dispersion of a polymer mainly composed of polyurethane containing no colorant is applied, dried, and then (1) finely divided polyurea is used. Polyurethane dispersion liquid in which polyurethane is dispersed, (2) Polyurethane solution in which fine particulate polyurethane is mixed, (3) Composition liquid in which polyoxyethylene-modified or glycerin-modified hardened oil is added to the polyurethane dispersion liquid in (1), ( 4) Applying at least one kind of liquid of (1) to (4) of a composition liquid in which a polyoxyethylene-modified or glycerin-modified hardened oil is added to the polyurethane solution of (2), and removing the solvent or dispersant, This is a method for producing a leather-like sheet, which is characterized by finishing by performing heat treatment and embossing as required.

A porous sheet comprising a fibrous base layer (1) constituting the leather-like sheet of the present invention and a surface layer (2) having a porous structure mainly composed of a polyurethane is a fibrous base layer.
Nylon-6, Nylon-6 as the fiber constituting (1)
6, nylon 610, polyamides such as polyamides containing aromatic rings, polyethylene terephthalate, copolymers of 80 mol% or more of ethylene terephthalate, polyesters such as polybutylene terephthalate, polyolefins such as polyethylene and polypropylene, polyacrylonitrile, polyvinyl At least one fiber selected from synthetic fibers such as alcohol and regenerated fibers, especially ultrafine fiber-generating multi-component obtained by spinning a synthetic polymer, if it is aimed at soft and drapeable and good appearance Fabrics such as woven fabrics, knitted fabrics, woven fabrics with napped fibers, woven fabrics with napped fibers, and fiber entangled non-woven fabrics using fibers or fibers mainly composed of ultrafine fiber-generating multi-component fibers to make them more similar to leather performance If so, the fabric is polyurethane, acrylic resin, synthetic rubber, polyester Eras It contains a resilient polymer mer such a SakuTsuta fibrous substrate sheet. Preferably, a multi-component fiber is used to form a fabric, and the multi-component fiber constituting the fabric is made into an ultrafine fiber by a chemical treatment and / or a mechanical treatment before the elastic polymer is contained or after the elastic polymer is contained. That is, the elastic polymer to be contained in the fabric is polyurethane, preferably a fibrous base sheet containing a porous polymer obtained by coagulating a solution or dispersion of a polymer mainly containing polyurethane-I described later into a porous structure. is there. A porous sheet in which a surface layer (2) having a porous structure of a polymer mainly containing polyurethane is provided on one surface of this fibrous base sheet. The polyurethane that constitutes the surface layer (2) is N, N′-
Polyurethane-I is a polyurethane mainly composed of dimethylformamide and soluble in a polar solvent, wherein the organic diisocyanate constituting the polyurethane is an organic diisocyanate containing an aromatic ring. A solution or dispersion of a polymer based on polyurethane-I is applied to one side of a fabric or fibrous substrate to solidify into a layer of porous structure. The porous structure may be a fine porous structure, but the surface layer having only the fine porous structure has large repulsion and poor drapability, and the crease crease shape and appearance are poor. With a mean diameter of 15-300 μm
Either a large bubble such as a sake bottle is mixed with fine pores as a predominant pore shape or is arranged through a fine porous diaphragm. Porous structure with an apparent density of 0.25 to 0.48 g / cm ³ This is the surface layer (2). The production of the polyurethane-I constituting the surface layer (2) having this porous structure is carried out by using a low molecular diol,
For example, ethylene glycol, propylene glycol,
1.4-butanediol, 1.5-pentanediol, 1.6-
Hexanediol, 3-methylpentanediol-1.
5 and at least one kind selected from dicarboxylic acids such as adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, isophthalic acid and terephthalic acid. Polyester glycol such as polyester diol, polyethylene ether glycol, polypropylene ether glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol, polycaprolactone glycol, polyvalerolactone glycol and the like, the average molecular weight of which is 100- At least one polymer diol selected from 3000 polymer diols is used as the soft segment. Examples of the organic diisocyanate containing an aromatic ring to be reacted with the polymer diol include, for example, tolylene diisocyanate, xylylene diisocyanate, phenylene diisocyanate, 4.4'-diphenylmethane diisocyanate, 2,2'-dimethyl-4.4'-diphenyl. At least one organic diisocyanate selected from methane diisocyanate and the like. This diisocyanate containing an aromatic ring is used because it has features such as stable formation of a porous structure as a leather-like sheet and high mechanical and physical stability of the pore structure. Therefore,
Other organic diisocyanates such as hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate, and isophorone diisocyanate may be used in combination as long as the properties of the leather-like sheet are not impaired. Preferred is an organic diisocyanate mainly containing 4.4'-diphenylmethane diisocyanate. And a compound having a molecular weight of 300 or less having two active hydrogen atoms as a chain extender, for example, ethylene glycol, propylene glycol, 1.4-butanediol, hexanediol, 3-methylpentanediol-1.5, 1.
4-Cyclohexanediol, diols such as xylene glycol, ethylenediamine, propylenediamine, xylenediamine, isophoronediamine, diamines such as piperazine, phenylenediamine, tolylenediamine, hydrazine, adipine dihydrazide, hydrazine such as isophthalic acid dihydrazide, or It is a polyurethane obtained by reacting with at least one selected from hydrazides and the like. The polyuriurethane obtained here (hereinafter referred to as polyurethane-I) is a polyurethane mainly composed of N, N'-dimethylformamide and soluble in a polar solvent. Polyurethanes that are soluble in other solvents, even those obtained by polymerization with the same composition, may have unfavorable surface layer states, such as crushing, deforming or redissolving the porous structure in the next treatment step. To obtain sufficient appearance performance. The resilience becomes large and the texture and workability of secondary products deteriorate.

The surface of the surface layer (2) is then treated by treating the surface of the fibrous substrate layer (1) with a porous surface layer (2) composed of a polymer mainly composed of polyurethane-I. The internal pores of the surface layer are exposed. That is, the surface of the surface layer is ground with sandpaper or the like to remove or destroy most of the surface to expose most of the internal pores of the surface layer. On the surface where the skin layer is mainly removed or destroyed, a polyurethane having a solvent different from that of the surface layer-constituting polyurethane-I is used, and the organic diisocyanate constituting the polyurethane is mainly an aliphatic diisocyanate and / or an alicyclic diisocyanate. A solution or dispersion of polyurethane-II composed of an organic diisocyanate to be added to the surface layer (2) by applying a polyurethane-II solid content of ^{2 to 20} g / m ² to remove the solvent or dispersant. A polyurethane-II coating film is formed on at least the surface of the porous polyurethane-I surface layer. The coating film of this polyurethane-II does not form a coating layer for forming a so-called smooth surface on the surface of the surface layer (2), but the cells 1 having a porous structure constituting the surface layer (2). It means that polyurethane-II was applied to each surface. After applying Polyurethane-II, or after applying Polyurethane-II
After applying II, a solution or dispersion of a polymer mainly composed of polyurethane-II is applied so that a discontinuous non-porous film is formed on the surface of the surface layer (2), and the solvent or dispersant is removed. Then, a discontinuous non-porous film is formed on the surface of the surface layer (2). Then, after applying polyurethane-II to the surface layer (2) or after forming a discontinuous film of a polymer mainly composed of polyurethane-II, heating embossing is performed to form an uneven pattern surface or a smooth surface on the surface. Therefore, it is finished in a leather-like appearance without blocking the pore tips existing on the surface. Polyurethane-II applied to this surface has a texture,
It is necessary that the polyurethane has a soft and tack-free slimy feel that affects the feel.
The production of such polyurethane-II can be accomplished by using low molecular diols such as ethylene glycol, propylene glycol, 1.4-butanediol, 1.5-pentanediol, 1.
6-hexanediol, 3-methylpentanediol-1.
5 and at least one kind selected from dicarboxylic acids such as adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, isophthalic acid and terephthalic acid. Polyester glycol such as polyester diol, polyethylene ether glycol, polypropylene ether glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol, etc., polylactone glycol such as polycaprolactone glycol, polyvalerolactone glycol, etc., these average molecular weights of 500- At least one polymer diol selected from 3000 polymer diols is used as the soft segment. Further, as the organic diisocyanate to be reacted with the polymer diol, for example, hexane diisocyanate, octane diisocyanate, 3-methoxy-1.6-hexane diisocyanate, nonane diisocyanate, decane diisocyanate, undecane diisocyanate,
At least selected from aliphatic diisocyanates such as dodecane diisocyanate, ω.ω'-diisocyanate-1.4- (or 1.2-) dimethylcyclohexane, cyclohexylmethane diisocyanate, 4.4'-dicyclohexylmethane diisocyanate, and alicyclic diisocyanates such as isophorone diisocyanate. It is one type of organic diisocyanate. And a compound having a molecular weight of 300 or less having two active hydrogen atoms as a chain extender, for example, ethylene glycol, propylene glycol, 1.4-butanediol, hexanediol, 3-methylpentanediol-1.5, 1.4-cyclohexanediol, xylene glycol, etc. At least selected from diols, ethylenediamine, propylenediamine, xylylenediamine, isophoronediamine, piperazine, phenylenediamine, tolylenediamine and other diamines, hydrazine, adipic acid dihydrazide, isophthalic acid dihydrazide and other hydrazines and hydrazides. It is a polyurethane obtained by reacting with one kind. Particularly preferred is a polyurethane obtained by extending a diamine. Polyurethane obtained here (hereinafter referred to as polyurethane-II)
Is a polyurethane having a solvent different from that of a polar solvent such as N, N'-dimethylformamide. Therefore, even if the polyurethane obtained by polymerizing with the same composition, N, N '
-Polyurethanes that are soluble only in polar solvents such as dimethylformamide are in an undesired state because they re-dissolve the polyurethane-I having a porous structure previously formed in the treatment step, or crush or deform the porous structure. Becomes Furthermore, such a polyurethane has a high degree of polymerization and side chains are exposed to reduce the flexibility, and the polyurethane has no slimy feel, so that the desired characteristics cannot be imparted in the present invention. As the solvent of polyurethane-II, for example, tetrahydrofuran, acetone, methyl ethyl ketone, cyclohexane, toluene, xylene, cyclohexane,
Solvents selected from ethyl acetate, methyl cellosolve, cellosolve acetate, isopropanol, diosane and the like are used alone or in combination. Also, N, N'-dimethylformamide may be mixed in an amount less than 15% of the range that does not damage the polyurethane-I. In that case, the bond between polyurethane-I and polyurethane-II is further improved, and the structural destruction strength of the porous surface layer is also increased. Further, polyurethane-II may be used as a composition in which a colorant, a light resistance stabilizer, an antioxidant, a luster modifier and the like are added.

Further, a polyurethane dispersion liquid in which fine particle polyurethane is dispersed or a polyurethane solution in which fine particle polyurethane is mixed is applied to the surface of the leather-like sheet in the present invention. The polyurethane is polyester diol, polyether diol, polyester ether diol. ,
Polymer diol having an average molecular weight of 500 to 2000 selected from polylactone diol, polycarbonate diol, etc., and hexane diisocyanate, octane diisocyanate, nonane diisocyanate, xylylene diisocyanate, cyclohexyl methane diisocyanate, ω,
ω'-diisocyanate-1.4- (or 1.2-) dimethylcyclohexane, 4.4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, perylene diisocyanate, tolylene diisocyanate, 4.4'-
At least one organic polyisocyanate such as diphenylmethane diisocyanate, 2.2'-dimethyl-4.4'-diphenylmethane diisocyanate, toluentisocyanate, biphenyl triisocyanate, 4.4'.4 "-triphenylmethane triisocyanate A fine particle polyurethane dispersion obtained by reacting at least one selected from molecular weight diols, triols, diamines, hydrazides and the like in a solvent system or a non-solvent system of polyurethane, or a polyurethane solution containing fine particle polyurethane. This fine-particulate polyurethane has the same composition as the raw materials used for polyurethane production.
Using a trifunctional raw material to form a cross-linked polyurethane as a part, or reacting the polymerization system during polyurethane production in the non-solvent or poor solvent of the polyurethane to be formed,
Such as depositing the polyurethane to be formed into particles,
Polyurethane dissolved in a solvent is mechanically dispersed in a non-solvent or a poor solvent for polyurethane to form fine particle polyurethane. The particle size of the particulate polyurethane is in the range of 1 to 20 μm, preferably 1.5 to 10 μm
It is possible to obtain the preferable ones in terms of surface appearance, surface strength and other physical properties.

Further, the polyoxyethylene-modified or glycerin-modified hardened oil used by being blended with the fine particle polyurethane is, for example, natural oil such as castor oil, linseed oil, cottonseed oil, poppy seed oil, tung oil, and synthetic unsaturated higher fatty acid. , For example, ricinoleic acid, linolenic acid, linolenic acid, etc. are treated as a raw material, and further treated with ethylene oxide in a mole number of 5 to 500 moles, preferably 10 to 100 moles of polyoxyethylene-modified hardened oil or glycerin-modified glycerin-modified Hardened oil. These hardened oils are compositions containing 5 to 100% by weight of fine particle polyurethane or a polyurethane mainly composed of fine particle polyurethane.

A fine particle polyurethane dispersion or a polyurethane solution in which fine particle polyurethane is mixed, or a composition liquid in which a polyoxyethylene-modified hardened oil or a glycerin-modified hardened oil is added to the dispersion or solution is a gravure method on the surface of a leather-like sheet. Apply by spraying, slit coating, etc. The coating amount is 0.5 to 15 g / m ² as polyurethane solid content. It is not preferable to increase the coating amount because it may impair the surface feel or deteriorate the surface properties.

Next, the leather-like sheet of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of a cross-sectional structure of the leather-like sheet of the present invention.
Is a fibrous substrate layer, 2 is a surface layer having a porous structure made of polyurethane-I (I in the figure), 3 is fine cells, and 4 is polyurethane-II (II in the figure) provided on the surface. Bubbles, 5 is the average diameter of pores with polyurethane-II provided on the surface 15-30
Large bubbles of 0 μm, and 6 are fine particle polyurethane forming the surface layer. FIG. 2 is a schematic view of a cross-sectional structure of a leather-like sheet according to another embodiment of the present invention, in which the surface layer 2 of the porous structure is a fine particle polyurethane of 6 and a polyoxyethylene modified or glycerin modified of 7 It is a surface formed of hardened oil. FIG. 3 is a scanning electron micrograph showing the embossed surface state of the leather-like sheet of one embodiment of the present invention, and FIG. 4 is a scanning electron micrograph enlarging a part of the surface state of FIG. Is.

A light resistance stabilizer, an antioxidant, a water / oil repellent, a colorant and the like may be added to the polyurethane-I and polyurethane-II constituting the surface layer of the present invention, and oxidation may be performed in the step of finishing a subcutaneous-like sheet. Treatments such as an inhibitor, a light stabilizer, a water / oil repellent, a softening agent, a coloring agent, and a coloring / discoloration preventing agent may be added.

The leather-like sheet obtained by the present invention has a soft and tactile feel with no tackiness on the surface, has a wrinkled crease shape and drapeability that is similar to natural leather and has a heavy feeling of pressure and flexibility, and a deep color. The leather-like sheet is especially good for shoes, sports shoes, clothing, bags, and has excellent performance such as moisture permeability, structural destruction strength, and surface strength.
It is useful for making products such as bags and gloves.

[Examples] Next, the present invention will be described with reference to specific examples. The parts and% in the examples relate to weight unless otherwise specified.

Example 1 Polyethylene adipate glycol 20 having an average molecular weight of 2000
Polyurethane-I was obtained by reacting 0 part, 163 parts of 4.4'-diphenylmethane diisocyanate and 34 parts of ethylene glycol. This polyurethane-I had a hard segment content of 49.6% (calculated value) and a solution viscosity of NN'-dimethylformamide solution having a concentration of 10% polyurethane at 30 ° C. was 2.9 poise. Using this polyurethane-I, as a polyurethane composition liquid for impregnating non-woven fabric, polyurethane 15, coagulation regulator 0.5 part, colorant 0.5 part, NN'-dimethylformamide 8
4.0 parts of the composition liquid was prepared. On the other hand, 13 parts of polyurethane as a polyurethane composition liquid for surface coating, a coagulation regulator 0.26
Parts, 0.25 part pore-forming regulator, 0.5 part colorant, and 1 part water
Part, NN'-dimethylformamide (85 parts).

Next, polyethylene terephthalate / polyethylene multi-component fiber made-up weight 470g / m ² apparent density 0.31g / cm ³ , thickness
Saturating the impregnated polyurethane composition liquid to a 1.5 mm fiber-entangled nonwoven fabric, and further applying a surface-coating polyurethane composition liquid on one surface in an amount of about 750 g / m ² , and then a NN'-dimethylformamide 30% aqueous solution, Polyurethane was coagulated by immersing it in a coagulation bath at a temperature of 28 ° C, polyethylene in the fiber was solvent extracted, washed with water and dried to contain polyurethane in a porous state in the ultrafine polyethylene terephthalate fiber bundle fiber entangled nonwoven fabric. One side of the fibrous base layer has an average pore diameter of 140
Approximately 0.35 mm in thickness with sake-like pores in the range of ~ 210 μm arranged almost perpendicular to the surface, and a porous surface layer with an apparent density of 0.28 g / cm ³ measured by slicing the surface layer and giving it The obtained porous sheet was obtained.

Then, the surface layer surface of the porous sheet was buffed with sandpaper to remove a thickness of about 0.08 mm. The skin layer was almost removed, and the surface became exposed with internal pores.

Polyurethane-II applied on the surface has an average molecular weight of 14
Polyurethane-II was obtained by reacting 140 parts of polycaprolactone glycol of 00, 81 parts of 4.4'-dicyclohexylmethane diisocyanate and 34 parts of isophoronediamine by a solution polymerization method. This polyurethane-II was dissolved in a mixed solvent of tetrahydrofuran / cyclohexanone / isopropanol, and a colorant was added to the polyurethane-II concentration 8%.
The solution was adjusted. This polyurethane-II solution was applied in two steps using the above-mentioned buffed surface gravure roll, and a liquid amount of about 5 g / m ² was applied as the amount of dried polyurethane.
This polyurethane was said to cover the surface of the porous structure up to about 0.2 mm from the surface. Then, the porous sheet A was obtained by drying, embossing, applying a surface colorant-added polyurethane and rubbing.

On the other hand, as the fine particulate polyurethane composition liquid applied to the surface of the porous sheet A, polyoxypropylene glycol, 4.4'-diphenylmethane diisocyanate, 4.4 '
Average particle size obtained by polymerizing 4 ″ -triphenylmethanetriisocyanate and isophoronediamine in a non-solvent system
A surface coating composition liquid (I) was prepared by mixing a 3.7 μm fine particle polyurethane dispersion in an amount of 80% polyurethane and a polyurethane-II solution in an amount of 20% polyurethane.
This composition liquid (I) is applied in two steps using a gravure roll,
An amount of polyurethane of about 4.5 g / m ² was applied and dried to obtain a leather-like sheet [I]. On this surface, there are an average of 1270 micropores / cm ² that are microscopic pores magnified 100 times under a microscope,
Moisture permeability 1370g / m ² · 24hr, breaking strength of the surface layer porous structure 5.9
It was excellent with kg / 25mm.

For comparison, the surface of the porous sheet A is made of polyurethane-
A solution of polyurethane-I having a solvent composition of NN'-dimethylformamide / tetrahydrofuran / cyclohexanone prepared by using I is coated in two steps using a gravure roll,
The amount of polyurethane applied was about 4.5 g / m ² . After drying, it was embossed and subjected to a rubbing treatment to obtain a leather-like sheet (II).
On the surface of this leather-like sheet, there are almost no micropores that are magnified 100 times, and the water vapor transmission rate is 685 g / m ^2.
It dropped to 24hr.

Further, for comparison, the surface coating composition liquid (I) containing the fine particulate polyurethane prepared in Example 1 was applied to the surface of the porous sheet in which the skin layer on the surface was not removed in two steps using a gravure roll. The amount of polyurethane applied was about 4.5 g / m ² . After drying, embossing and rubbing treatment were performed to obtain a leather-like sheet (III). The surface of this leather-like sheet does not show fine pores that are magnified 100 times, and the moisture permeability is 49%.
It dropped to 1g / m ² · 24hr.

Next, a sensory test was carried out by 20 inspectors who arbitrarily selected these leather-like sheets and conventional leather-like sheets. The results are shown in Table 1.

The product of the present invention was a leather-like sheet excellent in feeling and abrasion resistance.

Examples 2 to 8 As the surface coating composition liquid containing fine particle polyurethane to be applied on the surface, the fine particle polyurethane dispersion prepared in Example 1 and polyoxyethylene addition of 50% based on the amount of the fine particle polyurethane. A surface coating composition liquid (II) having a polyurethane concentration of 8% to which hardened castor oil was added was prepared.

In addition, the fine particle polyurethane dispersion prepared in Example 1 has a polyurethane content of 80%, and the polyurethane-II solution has a polyurethane content of 20%, based on the total polyurethane content.
A surface coating composition liquid (III) having a polyurethane concentration of 8% to which 40% polyoxyethylene addition-cured castor oil was added was prepared.

Next, the surface coating composition liquid prepared above was applied to the surface of the porous sheet A obtained in Example 1 using a gravure roll and dried to obtain a leather-like sheet. The performance of this leather-like sheet is shown in Table 2.

As a result of processing the present invention product into a Satsuka shoe and wearing it,
It was comfortable to wear and had excellent ball stickiness. Even when processed into men's shoes, it is flexible and comfortable to wear,
The color of the surface is dark and calm, and it looks like a shoe that is flexible from the viewpoint.

[Effects of the Invention] The leather-like sheet of the present invention is excellent in flexibility and drape, has a soft leather texture of natural leather, has a slimy feel, a large number of finely creased creases, and a color tone having a dark color feeling. It has a solid appearance and a soft feeling. Furthermore, the breaking strength of the porous structure of the surface layer is large, and the air permeability
It has excellent moisture permeability and abrasion resistance on the surface.

[Brief description of drawings]

FIG. 1 is a schematic view of a sectional structure of a leather-like sheet of the present invention, and FIG. 2 is a schematic view of a sectional structure of a leather-like sheet of another embodiment of the present invention. FIG. 3 is a 100 × scanning electron micrograph showing the surface condition of the leather-like sheet obtained in Example 1, which is an embodiment of the present invention, and FIG. 4 is a part of the surface condition of FIG. 3 is a scanning electron micrograph magnified 300 times.

Claims (4)

[Claims] 1. A surface layer comprising a fibrous substrate layer (1) and a skinless surface layer (2) having a porous structure of polyurethane-I, wherein the organic diisocyanate constituting the polyurethane is an aromatic ring-containing organic diisocyanate. Polyurethane-II in which the organic diisocyanate constituting the polyurethane is composed of an aliphatic diisocyanate and / or an organic diisocyanate mainly composed of an alicyclic diisocyanate is provided to the porous structure at least on the surface of (2), A leather-like sheet characterized in that the surface of the layer is a polyurethane coating film mainly composed of fine particle polyurethane. 2. The leather-like sheet according to claim 1, wherein the surface layer (2) has an apparent density of 0.25 to 0.48 g / cm ³ in which bubbles having an average pore diameter of 15 to 300 μm are predominantly present. . 3. A fibrous substrate layer (1) and a skinless surface layer (2) having a porous structure of polyurethane-I in which the organic diisocyanate constituting the polyurethane is an aromatic ring-containing organic diisocyanate. (2) at least the porous structure of the surface portion of the organic diisocyanate constituting the polyurethane is provided with a polyurethane-II composed of an organic diisocyanate mainly composed of an aliphatic diisocyanate or / and alicyclic diisocyanate,
A leather-like sheet characterized in that the surface of the surface layer is a coating film of a composition comprising polyurethane mainly composed of fine particle polyurethane and a polyoxyethylene-modified or glycerin-modified hardened oil. 4. The leather-like sheet according to claim ³ , wherein the surface layer (2) has an apparent density of 0.25 to 0.48 g / cm ³ in which bubbles having an average pore diameter of 15 to 300 μm are predominantly present. .