JPH10204782A - Production of leather-like sheet excellent in resistance to frictional fusing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a leather-like sheet that is excellent in resistance to fric tional fusion and abrasion, mechanical strength as tensile strength, durability as resistance to water and coldness and is rich in flexibility. SOLUTION: A leather-like laminated sheet comprising the fibrous base material and the non-porous polyurethane layer having an embossed pattern and a mirror face pattern is produced through the following steps (1)-(4) in turn: (1) the step that produces an elastomer layer (A) soluble in organic solvent to be used in the step (3), having a thickness of <=10μm, (2) the step that produce the film (C) of' a structure that non-porous layer is integrally laminated on the elastomer layer by casting the molten polyurethane insoluble in the organic solvent used in the step (3) on the elastomer layer (A), (3) the step that coating an organic solution or a solution of a thermoplastic elastomer in the same organic solvent, and (4) the step that the face of the elastomer layer (A) on the film (C) is laminated to the solvent or solution-coated face of the fibrous base material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is excellent in friction melting resistance and abrasion resistance, and has good mechanical properties such as tensile strength, durability such as water resistance, and properties such as cold resistance. It is rich in flexibility and flexibility, sports equipment,
The present invention relates to a method for producing a leather-like sheet that can be used for a wide range of uses such as shoes and bags by a method that is inexpensive and has excellent productivity.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a leather-like sheet having a grain surface layer, a polyurethane solution is coated on release paper, dried to form a film, and then the film is formed from a woven or nonwoven fabric. A so-called dry method, in which a release paper is peeled off from the surface of a material with an adhesive, is generally used. Further, on the surface of the substrate, a polyurethane solution is applied, a porous polyurethane layer is formed by a wet coagulation or dry coagulation method, and a resin solution containing a colorant is applied thereon and dried to form a colored layer. A method of forming a concavo-convex pattern with an embossing roll is also generally used.

[0003] Also, JP-A-53-62803 discloses that
It describes a method for producing a leather-like sheet in which a synthetic resin melt is extruded into a film shape using an extruder on a synthetic resin layer formed on a base material, integrated and embossed on the surface. In Japanese Patent Publication No. Hei 7-3033, there is described a method for producing a sheet in which a polyurethane melt extruded from a T-die is laminated on a metal deposition layer. In addition, Japanese Unexamined Patent Publication
No. 307986 discloses that a silane coupling agent is applied in advance to the surface of a synthetic fiber cloth, and then a thermoplastic resin is melt-extruded on the surface and pressure-bonded to the cloth.
A method for improving the adhesive strength between a fabric and a thermoplastic resin layer is described.

On the other hand, regarding the surface properties of a leather-like sheet, a conventional thermoplastic elastomer has a friction-melting resistance,
Low properties such as abrasion resistance. Therefore, for applications that require severe abrasion, such as shoe toe, for example, while maintaining the flexibility and feel, excellent properties such as friction-melting resistance, abrasion resistance, and tensile strength, Water resistance, cold resistance,
There is a demand for a leather-like sheet having various properties such as durability. On the other hand, the present inventors have proposed that a logarithmic viscosity produced using a polymer diol having a number average molecular weight of 1500 to 4000, an organic diisocyanate and a chain extender is 0.9 dl / g or more and a long-chain hard segment is heated. A thermoplastic polyurethane melt-molded film or sheet having a melt retention of 80% or more, wherein 30 mol% or more of the low molecular diol units constituting the high molecular diol used for the production of the thermoplastic polyurethane are 1,9 or more. A leather-like layer comprising a laminate of a thermoplastic polyurethane and a fibrous base material, which comprises nonanediol units and has a enthalpy of crystallization (ΔH) of 70 J / g or less for the polymer diol. Patent application for sheet.

[0005]

The method filed by this patent is to melt-extrude a thermoplastic polyurethane onto a fibrous base material and simultaneously press-bond it to produce a laminate. This has the advantage that the sheet can be formed simultaneously. Conventionally, as a method of manufacturing a laminate, a fibrous base material is coated with an organic solvent or a solution obtained by dissolving a thermoplastic elastomer in the solvent, and the solvent-coated surface of the fibrous base material is bonded to a film and dried. Is known. In this method, in comparison with the above-described method of simultaneously forming the grain surface layer and forming the leather-like sheet, a film for the grain surface layer is stocked, and optionally laminated in combination with a desired fibrous base material. It is used favorably in applications requiring small lot handling. However, polyurethane that satisfies the friction-melting resistance and abrasion resistance that are the objects of the present invention is structurally, because it is substantially insoluble in the organic solvent used during lamination, so that the film and the fibrous base material are In the method of applying and laminating an organic solvent or a solution in which a thermoplastic elastomer is dissolved in the solvent, only those having a remarkably low peel strength on the bonding surface can be obtained.

[0006] An object of the present invention is to have excellent friction melting resistance, abrasion resistance and bleeding whitening resistance while maintaining a soft and good feeling, and also to obtain mechanical properties such as tensile strength, water resistance and cold resistance. Another object of the present invention is to provide a method for efficiently and inexpensively laminating a separately prepared film for a silver surface layer and a fibrous base material when producing a leather-like sheet having various properties such as durability.

[0007]

As a result of intensive studies, the present inventors have found that the back surface of the polyurethane layer which is substantially insoluble in the organic solvent used for lamination is previously dissolved in the organic solvent used for lamination. 10μ thick made of elastomer
An integrated film in which the following layers are laminated has been manufactured, and it has been found that this object can be achieved by a method of laminating this and a fibrous base material when necessary, and the present invention has been completed based on these findings.

That is, the present invention provides a method for producing a leather-like sheet comprising a fibrous base material and a nonporous polyurethane layer having a concavo-convex pattern or a mirror-like pattern laminated on the surface thereof, as described in the following (1) to (4). ), (1) a thickness 1 of an elastomer soluble in an organic solvent used in the following step (3)
A step of forming a layer (A) of 0 μ or less, (2) the following (3)
A melt of polyurethane substantially insoluble in the organic solvent used in the step (a) is cast on the layer (A), a non-porous layer (B) is laminated on the layer (A), and an integrated film ( Forming a C), (3) applying an organic solvent or a solution obtained by dissolving a thermoplastic elastomer in the solvent to the fibrous base material,
(4) A method for producing a leather-like sheet, characterized by sequentially performing the steps of laminating and drying a solvent-coated surface of a fibrous base material and an elastomer (A) surface of a film (C).

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. First, a polyurethane nonporous layer (B) having an uneven pattern or a mirror pattern on the surface and an elastomer layer (A) are laminated to produce an integrated film (C). The resin constituting the non-porous layer corresponding to the surface layer is preferably a thermoplastic polyurethane in that strength, durability and performance similar to that of natural leather can be obtained. It must be a substantially insoluble polyurethane. In other words, by using a polyurethane having a partially cross-linked structure or a molecular chain highly entangled and substantially insoluble in an organic solvent, a high degree of friction-melting resistance and abrasion resistance is achieved. The resulting leather-like sheet can be obtained.

As such a polyurethane, conventionally known polyesters, polyethers, polycarbonates, and the like can be used, and a mixture of these may be used, or another thermoplastic elastomer may be blended. . The flow start temperature of the resin used for the surface layer is 120
C. to 260.degree. C., preferably 150.degree. C. to 240.degree. More preferably, the number average molecular weight is 1000-4.
000 ≦ b / (a + c) ≦ 1.10 (i) wherein the polyester polyol (a), the organic diisocyanate (b) and the chain extender (c) are represented by the following formula (i): Is the number of moles of the polyester polyol, b is the number of moles of the organic diisocyanate, and c is the number of moles of the chain extender). (A) the ester group concentration (the number of ester bonds / the total number of carbon atoms) is 0.08 to 0.17, the crystallization enthalpy (ΔH) is 70 J / g or less, and the number of hydroxyl groups per molecule is Is from 2.01 to 2.
08 thermoplastic polyurethanes. Such a thermoplastic polyurethane (hereinafter sometimes abbreviated as polyurethane) can be produced, for example, by the method described below.

The polyester polyol (a) used for producing the polyurethane is substantially composed of a polyol unit and a dicarboxylic acid unit. Examples of the polyol unit constituting the polyester polyol (a) include ethylene glycol, diethylene glycol, ,
4-butanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-
Low molecular weight diols containing two primary hydroxyl groups in one molecule such as methyl-1,8-octanediol, 1,9-nonanediol; glycerin, trimethylolpropane, hexanetriol, pentaerythritol, diglycerin, methylglycol Examples include units derived from a low molecular weight polyol having three or more hydroxyl groups in one molecule such as oxide, and one or more of these units may be included. Among these, it is preferable to include a 1,9-nonanediol unit from the viewpoint that a polyurethane excellent in friction-melting resistance and hydrolysis resistance can be obtained, and from the viewpoint that a polyurethane excellent in cold resistance can be obtained. It is also preferable to include -methyl-1,5-pentanediol unit, and it is also preferable to include trimethylolpropane from the viewpoint that a polyurethane having excellent friction-melting resistance and heat resistance can be obtained.

The dicarboxylic acid unit constituting the polyester polyol (a) includes, for example, a saturated aliphatic dicarboxylic acid such as glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid; and a saturated aliphatic dicarboxylic acid such as cyclohexanedicarboxylic acid. Alicyclic dicarboxylic acids; aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, and isophthalic acid; unsaturated dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid; halogen-containing dicarboxylic acids such as tetrabromophthalic acid; Formable derivatives, or acid anhydrides thereof, and the like may be used, and two or more of these may be used. Further, if necessary, a small amount of a unit derived from a tribasic or higher polybasic acid such as trimellitic acid or pyromellitic acid may be contained. Among them, those using any of adipic acid, azelaic acid, and isophthalic acid are preferable because the obtained polyurethane has more excellent friction melting resistance and hydrolysis resistance.

The polyester polyol (a) has an ester group concentration (a value obtained by dividing the number of ester bonds in one molecule by the total number of carbon atoms in one molecule) of 0.08 to 0.17. It is preferable in terms of enhancing the friction melting property, heat resistance and melt moldability, and is in the range of 0.10 to 0.16 from the viewpoint that the obtained polyurethane has more excellent friction melting resistance, heat resistance and melt moldability. More preferably. When the ester group concentration of the polyester polyol is 0.
When it is less than 08, the melt moldability and cold resistance of the obtained polyurethane decrease, and when the ester group concentration is more than 0.17, the obtained polyurethane has friction-melting resistance, heat resistance and hydrolysis resistance. Is reduced.

Further, the polyester polyol (a)
Preferably has a crystallization enthalpy (ΔH) of 70 J / g or less. When the crystallization enthalpy (ΔH) of the polyester polyol is larger than 70 J / g,
The cold resistance of the obtained polyurethane is remarkably reduced, and cracks and the like are easily generated in a low-temperature (for example, −30 ° C.) atmosphere. Examples of a method for setting the crystallization enthalpy (ΔH) of the polyester polyol (a) to 70 J / g or less include, for example, 2-methyl-1,3-propanediol, 3- Low molecular weight diol components having a methyl group in the side chain such as methyl-1,5-pentanediol and 2-methyl-1,8-octanediol alone or low molecular weight diol components having a methyl group in these side chains Or a linear diol component, or an aromatic dicarboxylic acid component such as isophthalic acid, orthophthalic acid and terephthalic acid and an aliphatic dicarboxylic acid component as a dicarboxylic acid component constituting the polyester polyol (a). And the like. In addition,
The crystallization enthalpy (ΔH) referred to in the present invention is a value measured by the method described in the following Examples.

Further, the polyester polyol (a)
The number of hydroxyl groups per molecule is preferably in the range of 2.01 to 2.08, and more preferably 2.01 to 2.08.
7, more preferably from 2.02 to
Most preferably, it is in the range of 2.06. The number of hydroxyl groups per molecule of the polyester polyol (a) is 2.
When the number is less than 01, the molecular weight of the obtained polyurethane does not increase sufficiently, and the friction-melting resistance and the heat resistance decrease. On the other hand, when the number of hydroxyl groups per molecule is larger than 2.08, the heat resistance of the obtained polyurethane is reduced and the molding temperature is increased. Moldability deteriorates. As a method of setting the number of hydroxyl groups per molecule of the polyester polyol (a) to 2.01 to 2.08,
For example, as a polyol component constituting the polyester polyol (a), a low molecular weight diol component having two primary hydroxyl groups in one molecule and a low molecular weight polyol component having three or more hydroxyl groups in one molecule are used as a polyester polyol. A method in which the number of hydroxyl groups per molecule is in the above range, or a polyester polyol having two hydroxyl groups per molecule and a polyester polyol having two or more hydroxyl groups per molecule. Can be used in combination at any ratio so that the number of hydroxyl groups per molecule of the polyester polyol falls within the above range.

The number average molecular weight of the polyester polyol (a) is determined from the viewpoints of mechanical properties, friction and melting resistance, abrasion resistance, low-temperature properties, melt moldability and the like of the obtained polyurethane.
It is preferably from 1,000 to 4,000,
More preferably, it is 3500. When the number average molecular weight of the polyester polyol (a) is lower than 1000, the mechanical properties such as tensile strength, friction melting resistance, abrasion resistance, and low temperature properties of the obtained polyurethane are reduced, and
If it exceeds 00, when the obtained polyurethane is extruded, bumps such as fish eyes occur, and it becomes difficult to secure the stability of the discharge amount. The number average molecular weight of the polyester polyol referred to in this specification is JIS.
It is a number average molecular weight calculated based on a hydroxyl value measured according to K1577.

The polyester polyol (a) is produced by polycondensing the above-mentioned polyol component and dicarboxylic acid component, or an esterified product thereof by a conventionally known transesterification reaction or direct esterification reaction. In that case, the polycondensation reaction can be performed in the presence of a titanium-based or tin-based polycondensation catalyst, but when a titanium-based catalyst is used, the titanium-based It is preferable to deactivate the polycondensation catalyst.

When a titanium-based polycondensation catalyst is used in the production of the polyester polyol (a), any of the titanium-based polycondensation catalysts conventionally used in the production of polyester polyols can be used and is not particularly limited. Preferred examples of the titanium-based polycondensation catalyst include titanic acid, tetraalkoxytitanium compounds, titanium acylate compounds, and titanium chelate compounds. More specifically, tetraisopropyl titanate,
Tetraalkoxy titanium compounds such as tetra-n-butyl titanate, tetra-2-ethylhexyl titanate and tetrastearyl titanate; titanium acylate compounds such as polyhydroxytitanium stearate and polyisopropoxytitanium stearate; titanium acetyl acetate; triethanolamine Examples thereof include titanium chelate compounds such as titanate, titanium ammonium lactate, titanium ethyl lactate, and titanium octylene glycolate.

The amount of the titanium-based polycondensation catalyst used can be appropriately adjusted depending on the content of the target polyester polyol and the content of the polyurethane produced using the same, and is not particularly limited. About 0.1 to 50 ppm, preferably about 1 to 30 ppm, based on the total weight of the
pm is more preferable.

Examples of the method for deactivating the titanium-based polycondensation catalyst contained in the polyester polyol include, for example, a method in which the polyester polyol obtained by terminating the esterification reaction is brought into contact with water under heating to deactivate the polyester polyol. To a phosphoric acid, a phosphoric acid ester, a phosphorous acid, a phosphorous acid ester or the like. When the titanium-based polycondensation catalyst is deactivated by contact with water, water is added to the polyester polyol obtained by the esterification reaction in an amount of 1% by weight or more,
~ 150 ° C, preferably 90 ~ 130 ° C for 1-3
It is good to heat for hours. The deactivation treatment of the titanium-based polycondensation catalyst may be performed under normal pressure or under pressure. It is desirable to depressurize the system after deactivating the titanium-based polycondensation catalyst, since water used for deactivation can be removed.

The type of the organic diisocyanate (b) used in the production of the polyurethane is not particularly limited, and any of the organic diisocyanates conventionally used in the production of ordinary polyurethane can be used.
The following are preferred. Examples of the organic diisocyanate include 4,4′-diphenylmethane diisocyanate, p-phenylene diisocyanate, toluylene diisocyanate, 1,5-naphthylene diisocyanate, 3,3′-dichloro-4,4′-diphenylmethane diisocyanate, and xylylene diisocyanate. And aliphatic or alicyclic diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and hydrogenated xylylene diisocyanate. One or more of these organic diisocyanates are used. Among these, it is preferable to use 4,4'-diphenylmethane diisocyanate or p-phenylenediisocyanate. In addition, a tri- or higher functional polyisocyanate such as triphenylmethane triisocyanate can be used in a small amount as necessary.

As the chain extender used in the production of the polyurethane, any of those conventionally used in the production of ordinary polyurethanes can be used, and is not particularly limited. An active hydrogen atom capable of reacting with an isocyanate group is used in the molecule. To 2
It is preferable to use a low molecular compound having a molecular weight of 300 or less and a molecular weight of 300 or less. For example, ethylene glycol, 1,
4-butanediol, 1,6-hexanediol, 1,
4-bis (β-hydroxyethoxy) benzene, 1,4
Diols such as cyclohexanediol, bis (β-hydroxyethyl) terephthalate, xylylene glycol, hydrazine, ethylenediamine, propylenediamine, xylylenediamine, isophoronediamine,
Piperazine, piperazine derivative, phenylenediamine,
Examples thereof include diamines such as tolylenediamine, xylenediamine, adipic dihydrazide, and isophthalic dihydrazide, and amino alcohols such as aminoethyl alcohol and aminopropyl alcohol, and one or more of these are used.

In the production of polyurethane, it is preferable to react the above-mentioned polyester polyol (a), organic diisocyanate (b) and chain extender (c) at a ratio satisfying the following formula (i). 1.00 ≦ b / (a + c) ≦ 1.10 (i) (where a is the number of moles of the polyester polyol, b is the number of moles of the organic diisocyanate, and c is the number of moles of the chain extender)

If the value of b / (a + c) in the formula (i) is less than 1.00, the number average molecular weight of the obtained polyurethane after melt molding is not maintained at a sufficiently high level. Performance becomes insufficient. On the other hand, b
When the value of / (a + c) is larger than 1.10, the resulting polyurethane has poor melt moldability. Since various properties such as heat resistance and melt moldability of the obtained polyurethane become particularly good, the value of b / (a + c) is 1.005.
To 1.00, more preferably 1.00.
More preferably, it is in the range of 5 to 1.05.
More preferably, it is in the range of 1-1.04.

When producing a polyurethane, in addition to the polyester polyol (a) described above, if necessary,
Other polymeric polyols such as polycarbonate diols may be used in small amounts.

The polyurethane preferably contains a tin-based urethanization catalyst in an amount of 0.5 to 15 ppm in terms of the amount of tin atoms. 0.5 ppm of tin-based urethanization catalyst
When it is contained as described above, the number average molecular weight of the polyurethane is maintained at a sufficiently high level even after molding, so that the inherent physical properties of the polyurethane are effectively exhibited. If the content of the tin-based urethanization catalyst exceeds 15 ppm in terms of tin atoms, it is not preferable because the performance such as hydrolysis resistance and thermal stability tends to decrease.

Examples of the tin-based urethanization catalyst include, for example,
Tin octylate, monomethyltin mercaptoacetate, monobutyltin triacetate, monobutyltin monooctylate, monobutyltin monoacetate, monobutyltin maleate, monobutyltin maleate benzyl ester, monooctyltin maleate, monobutyltin maleate Benzyl ester salts, monooctyltin maleate, monooctyltin thiodipropionate, monooctyltin tris (isooctylthioglycolate), monophenyltin triacetate,
Dimethyltin maleate, dimethyltin bis (ethylene glycol monothioglycolate), dimethyltin bis (mercaptoacetic), dimethyltinbis (3-mercaptopropionate), dimethyltinbis (isooctylmercaptoacetate), Dibutyltin diacetate, dibutyltin dioctate, dibutyltin distearate, dibutyltin dilaurate, dibutyltin maleate, dibutyltin maleate polymer, dibutyltin maleate, dibutyltin bis (mercaptoacetic acid), dibutyltin bis (mercaptoacetic acid alkyl ester) , Dibutyltin bis (3-
Mercaptopropionic acid alkoxybutyl ester)
Salt, dibutyltin bis (octylthioglycol ester) salt, dibutyltin bis (3-mercaptopopionic acid) salt, dioctyltin maleate, dioctyltin maleate, dioctyltin maleate polymer, dioctyltin dilaurate, dioctyltin Bis (isooctylmercaptoacetate), dioctyltin bis (isooctylthioglycolate), dioctyltin bis (3-mercaptopropionic acid) salts and other tin acylate compounds, mercaptocarboxylates and the like can be mentioned. One or more of them are used. Among them, it is preferable to use dialkyltin diacylates such as dibutyltin distearate and dibutyltin dilaurate; and dialkyltin bismercaptocarboxylates such as dibutyltin bis (3-mercaptopropionate alkoxybutyl ester) salt.

The method for producing the polyurethane is not particularly limited, and the above-mentioned polyester polyol (a), organic diisocyanate (b), chain extender (c) and, if necessary, other components may be used for melt polymerization, It may be produced by any of a prepolymer method, a one-shot method, and the like, using a known urethanization reaction technique such as solution polymerization. Among them, it is preferable to perform melt polymerization under substantially no solvent,
Particularly, a continuous melt polymerization method using a multi-screw extruder is preferable.

During or after the polymerization of the polyurethane,
If necessary, a heat stabilizer, an antioxidant, an ultraviolet absorber, a flame retardant, a lubricant, a coloring agent, a hydrolysis inhibitor, a crystal nucleating agent, a weather resistance improver, which are usually used in producing polyurethane, Various additives such as tackifiers and fungicides, various organic and / or inorganic fibers such as glass fibers and organic fibers, talc, silica, and other inorganic fillers, etc., are appropriately added with one or more kinds. Is also good.

As a method for forming a nonporous polyurethane layer having an irregular pattern or a mirror pattern on the surface, a coloring agent and an antioxidant are added to a thermoplastic polyurethane chip, if necessary, and the extruder is used. After melt-kneading under heating and pressurizing, a method of extruding the film from a T-die in a molten state is used. The thickness of the surface layer is generally 10 μm or more and 400 μm or less, more preferably 30 μm or more and 300 μm or less in order to have a leather-like texture and satisfy physical properties such as surface strength, adhesive strength, and flexibility. . If the thickness of the surface layer is too thin, the pigment concentration (with respect to polyurethane) in the case of coloring in the same color tone increases, and the surface physical properties decrease. On the other hand, if the thickness of the surface layer is too large, the flexibility is deteriorated and a rubber-like feeling is not preferred. The polyurethane constituting the non-porous polyurethane layer (B) must be substantially insoluble in an organic solvent described below from the viewpoint of abrasion resistance and friction-melting resistance.

As a method for forming an uneven pattern or a mirror pattern on the surface, a method of melting and extruding a film from a T-die into a film shape on release paper having the uneven pattern or a mirror pattern and pressing with a pressing roll is generally used. But is not particularly limited. From the standpoint of increasing the productivity, that is, the production speed, a method in which shaping is performed simultaneously with the film forming using a shaping roll is preferable. The imprinting roll referred to in the present invention is an embossing roll having a mirror surface or an embossed pattern with a concavo-convex pattern on the surface, and may be a combination of a releasable embossed sheet and a normal roll. It is preferably an embossing roll having a mirror surface or an embossed pattern with a concavo-convex pattern on the surface, and when a mirror-patterned embossing roll is used, an enameled leather-like sheet will be obtained, but in some cases, the obtained enamel The surface may be made uneven by using a roll having an embossed pattern similar to the surface unevenness of the leather.

As a material for the roll, a metal roll is used in the case of an emboss roll. As the back roll, either a metal roll or an elastic roll may be used, but it is preferable to use an elastic roll from the viewpoint of pressing stability. The pressing pressure may be set according to the fluidity of the thermoplastic elastomer under conditions that satisfy moldability and adhesive strength. The film whose surface is shaped is peeled off from the shaping roll after the temperature of the thermoplastic elastomer is substantially lowered and the fluidity is lost. If the thermoplastic elastomer is peeled while still having fluidity, the uneven pattern or the mirror surface pattern is broken, so-called grain flow occurs, and a sheave uneven pattern or an extremely smooth mirror surface cannot be obtained. For this reason, it is preferable that the embossing roll has a structure in which a cooling liquid is circulated inside the roll as necessary, or a structure in which the vicinity of a peeling point is forcibly cooled by cold air.

Next, the process of laminating the polyurethane nonporous layer (B) on the elastomer layer (A) to produce the integrated film (C) will be described. The reason why this step is required in the present invention is as follows. In general, when a fibrous substrate and a film made of a high molecular weight polymer elastic body are bonded, it is possible to bond them with a normal adhesive. Therefore, it is preferable that the bonding surface is bonded by dissolving the resin or fiber constituting the fibrous substrate and the film with a common solvent. If it is necessary to increase the adhesive strength, a method of adding a resin soluble in the common solvent is used. For example, when bonding a polyurethane film and a fibrous substrate impregnated with a polyurethane elastomer, dimethylformamide or dimethylformamide in which polyurethane is dissolved is used as an adhesive solvent. However, the polyurethane film (B) of the present invention is substantially insoluble in such an adhesive solvent in order to maintain the abrasion-melting resistance, and when produced by the above method, the peel strength of the adhesive surface is low. It will be significantly lower. For this purpose, it is necessary to previously form an integrated film in which an elastomer layer soluble in an organic solvent used at the time of lamination is laminated on the bonding surface with the fibrous substrate.

The thickness of the elastomer layer (A) is preferably within a range that does not lower the feel and can secure a sufficient adhesive force, and is 10 μm or less. As the elastomer, known resins such as a polyurethane elastomer, a polyurethane urea elastomer, and an acrylonitrile-butadiene copolymer can be used, but a polyurethane elastomer is most preferable in terms of adhesion to the polyurethane layer of the surface layer. For forming the elastomer layer (A), for example, a method is used in which an elastomer solution is applied on release paper using a gravure roll, a knife coater, or the like, and dried to form a film.

In the method of laminating the polyurethane non-porous layer (B) and the elastomer layer (A), first, an elastomer layer (A) is formed on a support, and the polyurethane non-porous layer is formed thereon by the above-described method. The resin forming the material layer (B) is melt-extruded from a T-die into a film and laminated at the same time. At this time, applying an elastomer solution to the surface of the polyurethane non-porous layer (B) previously formed into a film using a gravure roll, a knife coater or the like, and drying and integrating the same, it is necessary to form the polyurethane non-porous layer (B). Since B) does not dissolve in the solvent of the elastomer solution, the adhesive strength at the interface between the polyurethane nonporous layer (B) and the elastomer layer (A) is low, which is not suitable.

Next, the fibrous base material used in the present invention can be used as long as it is a sheet having a moderate thickness and a sense of fulfillment, and a soft texture. Various fibrous base materials used in the production method of the above can be used as they are in the present invention. For example, ultra-fine fibers or bundled fibers thereof, porous hollow fibers, ordinary fibers, entangled nonwoven sheets composed of natural fibers, etc., knitted and woven sheets and / or a polymer elastic body such as polyurethane contained as a binder between the fibers of the sheets are contained. Among these, which include fibrous base materials, entangled nonwoven fabrics made of ultrafine fiber bundles are preferable, and the fineness of the fibers constituting the ultrafine fiber bundles is preferably 0.5 denier or less, Particularly desirable is 0.1 denier or less, and the total denier of the ultrafine fiber bundle is preferably in the range of 0.5 to 10 denier. Examples of the type of fiber include nylon-based fiber and polyester-based fiber.

[0037] Such ultrafine fibers are, for example, those having a higher dissolution rate than a mixed fiber or a composite fiber obtained by mixing or spinning two or more polymers having different solubility in a solvent into a sea-island type or a split type. The method of extracting and removing the polymer of the above with a solvent, the higher the rate of decomposition from the mixed fiber or composite fiber obtained by mixing or composite spinning two or more polymers having different decomposition rates with respect to the decomposing agent into a sea-island type or split type A method of decomposing and removing polymers with a decomposing agent, or mechanically or chemically fibrillating sea-island or split-type mixed or composite fibers obtained by mixing or spinning two or more polymers with low compatibility. It can be obtained by a known method such as a method of treating and forming a fiber and peeling off at the polymer interface.

In order to impart a natural leather feeling to the laminate, the fibrous base material may be impregnated with a polyurethane elastomer or another elastic polymer. In this case, the elastic polymer may be impregnated with a porous structure. By impregnating the fibrous base material in a state having the above, a laminate having a feeling closer to that of natural leather can be obtained. As a polymer elastic body, it is a resin conventionally used in the production of leather-like sheets,
Polyurethane-based resins, polyvinyl chloride-based resins, polyvinyl butyral-based resins, polyacrylic acid-based resins, polyamino acid-based resins, silicon-based resins and mixtures of these resins, and these resins are of course copolymers Good. In order to impregnate the polyurethane elastomer or other elastic polymer into the fibrous base in a porous state, for example, a method of impregnating the fibrous base with a solution of the elastic polymer and wet coagulating the elastic polymer may be employed. I just need. As the polymer elastic body constituting at least the surface portion of the fibrous base material, the same kind as the thermoplastic elastomer used for surface finishing is preferable in terms of adhesiveness, and particularly, polyurethane has strength and natural leather-like performance. It is preferred in that respect. The weight ratio of the fibers constituting the fibrous base material to the elastic polymer is preferably in the range of 90:10 to 40:60 by weight.

The fibrous substrate may be brushed on one or both sides in order to enhance the adhesion to the polyurethane layer and to give a leather-like appearance. May be added. Further, a porous and / or nonporous coating layer made of an elastic polymer or an inelastic polymer may be formed on one or both surfaces of the fibrous substrate before forming the polyurethane layer.
The surface of such a coating layer may be roughened with sandpaper or the like, if necessary, or may be formed with embossing rolls or the like. Such a coating layer may be formed as a continuous layer on one or both sides of the fibrous substrate, or may be formed as a discontinuous layer.

The thickness of the fibrous base material can be arbitrarily selected depending on the use of the obtained synthetic leather, and is not particularly limited. However, from the viewpoint of the balance with the intermediate layer and the surface layer, the thickness is preferably from 0.3 mm to 0.3 mm. 3 mm, particularly preferably 0.5 mm to
The range is 2.0 mm.

The adhesion between the fibrous base material and the film (C) is performed by first applying an organic solvent or a solution obtained by dissolving a thermoplastic elastomer in the solvent on one side of the fibrous base material. By superimposing the film (C) on the elastomer (A) surface, pressing, and then drying,
Complete. As a coating method, a gravure roll, a knife coater, or the like may be used, but it is necessary to use equipment capable of stacking films before the coating liquid dries. The organic solvent can be selected according to the type of resin used, production equipment, and the like.For example, dimethylformamide, dimethylacetamide, dimethylsulfoxide, toluene, methylethylketone, and the like can be used. Can also. The amount of the organic solvent to be applied is preferably in the range of 10 to 100 g / m ² , and more preferably in the range of 20 to 60 g / m ² .

When it is necessary to further increase the adhesive strength, a method in which a resin soluble in a solvent is added and applied is used. The resin used in this case is desirably an elastomer such as a polyurethane elastomer, a polyurethane urea elastomer, or an acrylonitrile-butadiene copolymer, since the resin does not reduce the feeling. From the viewpoint of adhesive strength, the resin (A) and the elastomer (A) surface of the film (C) are preferably used. More preferably, they are of the same type.

The laminate of the present invention comprising the polyurethane layer and the fibrous base material layer thus obtained has excellent mechanical properties such as excellent friction-melting resistance, abrasion resistance, bleeding whitening resistance and tensile strength. Due to its various properties such as physical properties, durability, cold resistance, flexibility, flexibility, and touch, it can be effectively used for applications such as sports equipment, shoes, and bags.

[0044]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited by these examples. In the following Reference Examples, Examples and Comparative Examples, the measurement or evaluation of the crystallization enthalpy (ΔH), the friction melting resistance, and the wear resistance (Taber wear resistance) were performed according to the following methods.

[Crystalization enthalpy (ΔH)] Differential scanning calorimeter [Rigaku Thermal Analysis, manufactured by Rigaku Corporation]
Station TAS10], the crystallization enthalpy (ΔH) of the polyester polyol was measured. The amount of the sample was about 10 mg, and calorimetry was performed under a nitrogen stream (100 ml / min) under the conditions shown in Table 1 below, and the crystallization enthalpy (ΔH) was obtained from the peak area in step 3.

[Friction-melting resistance] A strip-shaped test piece (3 cm x 6 cm) was prepared from a polyurethane laminate, and a roller made of cherry (diameter: 73 mm, width: width) rotating the polyurethane layer side of the strip-shaped test piece at 1800 rpm. 26 mm) under a load of 1.5 lb for 2 seconds, the friction melting area (cm 2) of the test piece was measured, and the state of the friction melting surface was visually observed. went.

：: Friction melting hardly occurred △: Friction melting slightly occurred ×: Friction melting was large and defective

[Abrasion resistance (Taber abrasion)] JIS
It was measured according to K7204. That is, a circular test piece having a diameter of 12 cm was cut out from the polyurethane laminate. On the polyurethane layer side of this circular test piece, a wear wheel (H-
22) and apply a circular test piece with a load of 1 kgf to 1000
The abrasion test was performed by rotating the test piece, and the weight of the test piece after the abrasion test was subtracted from the weight of the test piece before the abrasion test to obtain the Taber abrasion amount (the weight reduced by abrasion) (g).

Reference Example 1 (Production of Polyester Polyol) 9173 g of 3-methyl-1,5-pentanediol and 9641 g of adipic acid were charged into a reactor, and the mixture was added under normal pressure.
The esterification reaction was carried out while distilling off water generated at 00 ° C. out of the system. When the acid value of the reactant becomes 30 or less,
90 mg of tetraisopropyl titanate was added as a titanium-based polycondensation catalyst, and the reaction was continued while reducing the pressure to 200 to 100 mmHg. When the acid value reached 1.0, the degree of vacuum was gradually increased by a vacuum pump to complete the reaction. Thereafter, the mixture was cooled to 100 ° C., 3% by weight of water was added thereto, and the mixture was heated with stirring for 2 hours to deactivate the titanium-based polycondensation catalyst. After water was distilled off under reduced pressure, tin was added thereto. Dibutyltin diacetate as a urethanization catalyst
0 ppm (3.4 ppm in terms of tin atom) was added. As a result, a polyester polyol (hereinafter, referred to as PMPA) to which a tin-based urethanization catalyst was added after deactivating the titanium-based catalyst was obtained. The obtained polyester polyol had a number average molecular weight of 2000, the number of hydroxyl groups per molecule was 2.00, the ester group concentration was 0.156, and the crystallization enthalpy (ΔH) was not detected.

REFERENCE EXAMPLE 2 (Production of Polyester Polyol) Reference Example 2 was repeated except that a mixture of 3-methyl-1,5-pentanediol and trimethylolpropane in a molar ratio of 10: 1.22 was used as a polyol component. After the esterification reaction was performed in the same manner as in Example 1, the titanium-based polycondensation catalyst was deactivated, and a tin-based urethanation catalyst was added to obtain a polyester polyol (hereinafter referred to as PMPPA).
). The number average molecular weight of the obtained polyester polyol was 2,000, the number of hydroxyl groups per molecule was 3.00, the ester group concentration was 0.157, and the crystallization enthalpy (ΔH) was not detected.

Reference Example 3 (Production of Polyurethane) The polyester polyol obtained in Reference Example 1 was used as a polyester polyol.
MPA and PMPPA obtained in Reference Example 2, butanediol (hereinafter referred to as BD) as a chain extender, and 4,4′-diphenylmethane diisocyanate (hereinafter referred to as MDI) heated and melted at 50 ° C. as an organic diisocyanate. ) To (PMPA: PMPP
A): The molar ratio of MDI: BD is (0.97: 0.0
3): 3.88: 2.80 and the total amount of these is 20
Twin screw type extruder (30 mmφ, L / D
= 36) to perform continuous melt polymerization at 260 ° C. The resulting polyurethane melt was continuously extruded into water in a strand form, then cut with a pelletizer, and the pellets were dehumidified and dried at 80 ° C. for 6 hours. This polyurethane does not dissolve in dimethylformamide.

Reference Example 4 (Production of Polyurethane) The polyester polyol obtained in Reference Example 1 was used as a polyester polyol.
MPA, butanediol as a chain extender (hereinafter referred to as BD), and 5 as an organic diisocyanate
4,4′-diphenylmethane diisocyanate (hereinafter referred to as MDI) melted by heating to 0 ° C.
A: MDI: BD molar ratio of 1: 3.88: 2.80
, And continuously fed from a metering pump to a twin-screw extruder (30 mmφ, L / D = 36) that rotates coaxially so that the total amount of these becomes 200 g / min. Melt polymerization was performed. The resulting polyurethane melt is continuously extruded into water in the form of a strand and then cut with a pelletizer.
It was dehumidified and dried at 0 ° C. for 6 hours. This polyurethane dissolves in dimethylformamide.

Reference Example 5 (Production of Fibrous Substrate) 50 parts by weight of polyethylene as a sea component and 50 parts by weight of 6-nylon as an island component were melt-spun in the same melting system to produce a composite fiber having a single fiber fineness of 10 denier. did. The composite fiber was stretched 3.0 times, crimped, cut to a fiber length of 51 mm, defibrated with a card, made into a web with a cross wrapper webber, and then 650 g / m ^{2 in area} by needle punch. Fiber entangled nonwoven fabric. 16 parts by weight of a polyurethane composition mainly composed of polyester polyurethane and dimethylformamide 84
After impregnating with a solution consisting of parts by weight, coagulating and washing with water, the polyethylene in the composite fiber is extracted and removed in toluene, and the bundled fiber consisting of 6-nylon ultrafine fibers having an average of 0.01 denier and the polyurethane binder are used. 1.3mm thick
Was obtained.

Example 1 A polyurethane obtained by polymerizing 3-methyl-1,5-pentanediol, butanediol, and 4,4'-diphenylmethane diisocyanate was dissolved in dimethylformamide, and gravure rolled onto release paper. It was applied and dried to produce a polyurethane layer having a thickness of 7 μm. continue,
Between this polyurethane layer and release paper (DE-14: manufactured by Dai Nippon Printing Co., Ltd.) having a textured embossed pattern, 100 parts of the polyurethane pellets produced in Reference Example 3 and white pigment pellets (pigment concentration 30%: resin polyethylene) 5) The polyurethane composition mixed with 5 parts was extruded using an extruder and a T-die.
At a melting zone temperature of 235 ° C. and a die introduction part temperature of 235 ° C., the film was supplied in a molten state while being formed into a film. After pressing with metal roll and elastic roll, peel off release paper,
A polyurethane nonporous surface layer having an average thickness of 200 μm and having a grain was obtained. Next, 40 g / m ² of dimethylformamide was applied to one surface of the fibrous base material prepared in Reference Example 5 using a 140 mesh gravure roll, and about 1 second before the dimethylformamide was dried, the polyurethane nonporous surface layer was coated. Were overlapped so that the 7 μm-thick polyurethane layer was on the inside, pressed, and dried. Table 1 below shows the physical property values of the obtained leather-like sheet.

Example 2 One surface of the fibrous base material prepared in Reference Example 5 was polymerized from 3-methyl-1,5-pentanediol, butanediol, and 4,4'-diphenylmethane diisocyanate with a 140 mesh gravure roll. 5 g / m ² of a 5% solution of the polyurethane obtained in dimethylformamide was applied,
About 1 second before drying, the polyurethane nonporous surface layer used in Example 1 was overlaid, pressed, and dried.

Comparative Example 1 A leather-like sheet was produced in exactly the same manner as in Example 1 except that the polyurethane pellets produced in Reference Example 4 were used.

Comparative Example 2 100 parts of the polyurethane pellets prepared in Reference Example 3 and white pigment pellets (30% pigment concentration: resin) were placed on release paper (DE-14: manufactured by Dai Nippon Printing Co., Ltd.) having a textured embossed pattern. Polyethylene) 5 parts of a polyurethane composition mixed,
Using an extruder and a T-die, the mixture was fed in a molten state at a melting zone temperature of 235 ° C. and a die introducing portion temperature of 235 ° C. while forming a film into a film. After pressing with a metal roll and an elastic roll, the release paper is peeled off, and the average
A polyurethane nonporous surface layer of 00 μm was obtained. Next, on one surface of the fibrous substrate prepared in Reference Example 5, a 140 mesh gravure roll was used to polymerize 3-methyl-1,5-pentanediol, butanediol, and 4,4′-diphenylmethane diisocyanate. 5% dimethylformamide solution of polyurethane is applied, and after about 1 second,
The polyurethane nonporous surface layer was overlaid, pressed and dried.

[0058]

[Table 1]

[0059]

The leather-like sheet obtained according to the present invention comprises:
It is excellent in friction melting resistance, abrasion resistance, mechanical properties such as tensile strength, durability such as water resistance, properties such as cold resistance, and has excellent flexibility and flexibility. It can be effectively used for a wide range of uses such as sports equipment, shoes, bags, bags and other bags, boxes, interior materials for buildings such as houses, cosmetics for furniture, and clothing.

Claims (2)

[Claims] When producing a leather-like sheet comprising a fibrous base material and a nonporous polyurethane layer having a concavo-convex pattern or a mirror-like pattern laminated on the surface, the following (1) to (4)
(1) A layer (A) having a thickness of 10 μ or less made of an elastomer soluble in an organic solvent used in the following step (3)
(2) casting a melt of a polyurethane substantially insoluble in an organic solvent used in the following step (3) on the layer (A) to form a nonporous layer on the layer (A). Laminating the layer (B) to form an integrated film (C), (3) applying an organic solvent or a solution obtained by dissolving a thermoplastic elastomer in the solvent to the fibrous base material, (4) fiber A method for producing a leather-like sheet, comprising sequentially performing a step of laminating and drying a solvent-coated surface of a quality base material and an elastomer (A) surface of a film (C). 2. The layer (B) having a number average molecular weight of 1,000 to 4,
000 ≦ b / (a + c) ≦ 1.10 (i) wherein the polyester polyol (a), the organic diisocyanate (b) and the chain extender (c) are represented by the following formula (i): Is the number of moles of the polyester polyol, b is the number of moles of the organic diisocyanate, and c is the number of moles of the chain extender). The polyester polyol (a) used in the production of the polyester polyol has an ester group concentration (number of ester bonds / total number of carbon atoms) of 0.08 to 0.17 and an crystallization enthalpy (ΔH) of 70 J / g or less. The method for producing a leather-like sheet according to claim 1, wherein the number of hydroxyl groups per molecule is 2.01 to 2.08.