WO2013027489A1 - Leather-like sheet and method for producing same - Google Patents

Abstract

The present invention addresses the problem of providing a urethane resin composition for forming a surface skin layer of a leather-like sheet, said urethane resin composition enabling the formation of the surface skin layer which has an excellent durability, such as perspiration resistance and oil resistance, at such a level that the leather-like sheet shows neither deterioration in appearance nor peeling from a substrate over time even in the case where, for example, sweat, oil or the like sticks thereto. The leather-like sheet according to the present invention is characterized by comprising: a surface skin layer (C) formed by using a urethane resin composition comprising a urethane resin (A) that has two or more hydroxyl groups at least at one end thereof, and an aqueous medium (B); an adhesive layer (D); and a substrate layer (E).

Description

Leather-like sheet and manufacturing method thereof

The present invention relates to a leather-like sheet such as synthetic leather or artificial leather.

Leather-like sheets such as synthetic leather and artificial leather have excellent textures comparable to natural leather, so they are used in various fields including clothing, furniture, vehicle interior materials, shoes, bags, etc. Yes.

As the leather-like sheet, generally, an intermediate layer such as a porous layer is laminated on the surface of a support such as a fibrous base material, and a skin layer made of urethane resin or the like is further laminated on the surface. There are many things, and each layer is required to have its own characteristics. Specifically, the intermediate layer is required to have a soft texture, and the skin layer is often required to have durability such as sweat resistance and oil resistance in addition to the flexibility.

In particular, the durability such as sweat resistance required for the skin layer is not limited to the use of the leather-like sheet, even when sweat or oil components adhere to the surface of the skin layer. This is a characteristic that is particularly regarded as important in maintaining high quality over a long period of time without causing changes in the appearance or deterioration of the film and a decrease in the adhesion of the skin layer to the support.

As a leather-like sheet provided with the above-described skin layer, for example, a fiber laminate manufacturing method in which a fiber base material and a skin layer formed of a synthetic resin film are bonded by a dry laminating method using an adhesive. A fiber laminate, wherein the fiber substrate (A layer) is treated with an aqueous polypolyurethane resin containing one or more of a hydroxyl group, an amino group, or an imino group in a molecular skeleton. A manufacturing method is known (for example, refer to Patent Document 1).

However, when the skin layer used for the production of the fiber laminate is exposed to sweat or oil components for a long time, the skin layer may cause swelling or cracking of the skin layer and a significant decrease in adhesive strength. In some cases, the appearance of the leather-like sheet is poor, or the peeling from the support with time is caused.

JP 2005-206970 A

The problem to be solved by the present invention is, for example, a level of resistance that does not cause poor appearance of the leather-like sheet or time-lapse peeling from the support even when sweat or oil components adhere to it. An object of the present invention is to provide a leather-like sheet having a skin layer excellent in durability such as sweat resistance and oil resistance.

The inventors have found that the above-mentioned problems can be solved by using a urethane resin in which two or more hydroxyl groups are present at the terminals present in the urethane resin, in order to solve the above-mentioned problems. .

That is, the present invention relates to a skin layer (C) formed using a urethane resin composition containing at least one hydroxyl group at a terminal and a urethane resin composition containing an aqueous medium (B). The present invention relates to a leather-like sheet having an adhesive layer (D) and a support layer (E).

The leather-like sheet of the present invention is a level that does not cause poor appearance of the leather-like sheet or peeling over time from the support even when sweat, oil, solvent, etc. adhere to the skin layer. Therefore, it can be used for manufacturing clothing, furniture, vehicle interior materials, shoes, bags, and the like.

The leather-like sheet of the present invention comprises a skin layer (C) formed using a urethane resin composition containing a urethane resin (A) having two or more hydroxyl groups at at least one end and an aqueous medium (B). And an adhesive layer (D) and a support layer (E).

Examples of the urethane resin composition that can be used to form the skin layer (C) include a urethane resin (A) having two or more hydroxyl groups at the terminal, an aqueous medium (B), and other additives as necessary. The thing containing etc. can be used.

In the present invention, it is indispensable to use a urethane resin (A) having two or more hydroxyl groups at least at one end as the urethane resin. Specifically, the urethane resin (A) has two or more hydroxyl groups at at least one terminal among two or more resin terminals that may exist in the urethane resin. For example, when the urethane resin is obtained by reacting a diol and diisocyanate and has two ends in the urethane resin, it has two or more hydroxyl groups at at least one of the ends. Is. Two or more hydroxyl groups may be present at each of the two ends. In addition, when the urethane resin has a multi-branched structure and has three or more terminals, it has two or more hydroxyl groups at least at one terminal.

Here, when a urethane resin having one hydroxyl group at one end is used instead of the urethane resin (A), a skin layer having excellent durability such as sweat resistance and oil resistance is formed. In some cases, the appearance of the leather-like sheet may be poor, and the skin layer (C) may be peeled off from the adhesive layer (D) or the support (E). In addition, instead of the urethane resin (A), when a urethane resin bonded to the urethane main chain is used instead of a terminal hydroxyl group, a skin layer having excellent durability such as sweat resistance and oil resistance is formed. In some cases, the appearance of the leather-like sheet may be poor, and the skin layer (C) may be peeled off from the adhesive layer (D) or the support (E).

The number of hydroxyl groups that can be present in the urethane resin (A) is preferably 2 to 3 and more preferably 2 with respect to one end. Further, two or more hydroxyl groups may be present at each of all terminals present in the urethane resin (A). The urethane resin (A) preferably has a hydroxyl value in the range of 10-50.

As the urethane resin (A), for example, a so-called linear urethane resin obtained by using a diol as the polyol (a1) and a diisocyanate as the polyisocyanate (a2) is used. Using at least two, preferably two, hydroxyl groups at each of the ends is particularly flexible without impairing durability such as heat resistance (water), sweat resistance, and oil resistance. It is preferable because an excellent skin layer (C) can be formed.

The urethane resin (A) preferably has a hydrophilic group for stable dispersion in the aqueous medium (B).

As the hydrophilic group, for example, an anionic group, a cationic group, or a nonionic group can be used. Especially, when forming the skin layer (C), it is more preferable to use an anionic group in order to quickly increase the viscosity of the urethane resin composition used in the present invention.

As the anionic group, for example, a carboxyl group, a carboxylate group, a sulfonic acid group, a sulfonate group and the like can be used. Among them, a carboxylate group partially or wholly neutralized with a basic compound or the like Use of a sulfonate group is preferable in producing a composite resin having good water dispersibility.

Examples of basic compounds that can be used for neutralizing the anionic group include organic amines such as ammonia, triethylamine, pyridine, and morpholine, alkanolamines such as monoethanolamine, sodium, potassium, lithium, and calcium. A metal base compound etc. are mentioned.

When a carboxylate group or a sulfonate group is used as the anionic group, they are present in the range of 50 mmol / kg to 1,000 mmol / kg of the entire urethane resin (A). It is preferable for maintaining good water dispersion stability.

Moreover, as said cationic group, a tertiary amino group etc. can be used, for example.
Examples of the acid that can be used for neutralizing a part or all of the tertiary amino group include organic acids such as acetic acid, propionic acid, lactic acid, and maleic acid, sulfonic acid, methanesulfonic acid, and the like. Organic sulfonic acids and inorganic acids such as hydrochloric acid, sulfuric acid, orthophosphoric acid and orthophosphorous acid may be used alone or in combination of two or more.

Examples of the quaternizing agent that can be used for quaternizing a part or all of the tertiary amino group include dialkyl sulfates such as dimethyl sulfate and diethyl sulfate, methyl chloride, and ethyl chloride. Alkyl halides such as benzyl chloride, alkyls such as methyl methanesulfonate and methyl paratoluenesulfonate, and epoxies such as ethylene oxide, propylene oxide, and epichlorohydrin may be used alone or in combination of two or more.

Examples of the nonionic group include polyoxyalkylene groups such as polyoxyethylene group, polyoxypropylene group, polyoxybutylene group, poly (oxyethylene-oxypropylene) group, and polyoxyethylene-polyoxypropylene group. Can be used. Among these, it is preferable to use a polyoxyalkylene group having an oxyethylene unit in order to further improve the hydrophilicity.

As the urethane resin (A) used in the present invention, one having a weight average molecular weight in the range of 10,000 to 50,000 is used from the viewpoint of forming a skin layer having excellent durability such as sweat resistance. It is preferable to use 20,000 to 50,000.

The urethane resin (A) is, for example, a step of producing a urethane prepolymer having an isocyanate group at a terminal by reacting the polyol (a1), the polyisocyanate (a2), and a chain extender (a3) as necessary. (Step 1) and the step of reacting the urethane prepolymer and polyalkanolamine (Step 2) can be used.

First, step 1 will be described.
The said process 1 is a process of manufacturing the urethane prepolymer which has an isocyanate group at the terminal by making the said polyol (a1), polyisocyanate (a2), and the chain extender (a3) react as needed. Specifically, the polyol (a1), the polyisocyanate (a2) and, if necessary, the chain extender (a3) are mixed in the absence of a solvent or in the presence of an organic solvent, and the mixture is mixed at 50 ° C. to 100 ° C. It can be produced by reacting for about 3 to 10 hours. In addition, after reacting the polyol (a1) and the polyisocyanate (a2) in the same manner as described above, the reactant and the chain extender (a3) are mixed and further reacted to achieve the purpose. It is also possible to produce a urethane prepolymer having an isocyanate group at the terminal.

As the polyol (a1) usable in the step 1, for example, polycarbonate polyol, polyester polyol, polyether polyol and the like can be used. Of these, the use of polycarbonate polyol is preferable for further improving the sweat resistance of the skin layer (C).

As the polycarbonate polyol, for example, a product obtained by reacting a carbonate with a low molecular weight polyol of about 100 to about 500 can be used.

As the carbonate ester, methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclocarbonate, diphenyl carbonate, or the like can be used.

Examples of the low molecular weight polyol that can react with the carbonate ester include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, 1,4-butanediol, 1, 3-butanediol, 1,2-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 2,5-hexanediol, 1,6-hexanediol, 1,7 -Heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1, -Propanediol, 2-methyl-1,8-octanediol, 2-butyl-2-ethylpropanoldiol, 2-methyl-1,8-octanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol Relatively low molecular weight dihydroxy compounds such as hydroquinone, resorcin, bisphenol A, bisphenol F, 4,4'-biphenol, polyether polyols such as polyethylene glycol, polypropylene glycol, polyoxytetramethylene glycol, and polyhexamethylene adipate Polyester polyols such as polyhexamethylene succinate and polycaprolactone can be used.

The polycarbonate polyol preferably has a number average molecular weight of 500 to 3,000. Among these, from the viewpoint of further improving the heat resistance (water) resistance and sweat resistance of the skin layer (C), it is preferable to use a polycarbonate polyol having a number average molecular weight of 500 to 1,500. On the other hand, when forming the skin layer (C) that has both excellent heat resistance (water) resistance, sweat resistance, oil resistance, and other excellent flex resistance, the skin layer (C) is preferably A polycarbonate polyol having a number average molecular weight of 1,500 to 3,000, more preferably 1,600 to 2,500 can be used.

The polycarbonate polyol is preferably used in the range of 20% by mass to 95% by mass with respect to the total amount of the polyol (a1).

As the polyester polyol, for example, those obtained by esterifying a low molecular weight polyol of about 100 to 500 and a polycarboxylic acid can be used.

Examples of the low molecular weight polyol include 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 2,5-hexanediol, 1,6-hexanediol, 1 , 7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-methyl-1,3- Aliphatic polyols such as propanediol, cyclobutanediol, B pentanediol, 1,4-cyclohexanediol, cycloheptane diol, can be used cyclooctane diol, cyclohexane dimethanol, an aliphatic cyclic structure-containing polyols such as hydroxypropyl cyclohexanol.

Examples of the polycarboxylic acid that can be used in the esterification reaction with the low molecular weight polyol include aliphatic polycarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic acid, and fumaric acid. Aromatic polycarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, and anhydrides or ester-forming derivatives thereof can be used.

Further, as the polyether polyol, for example, one obtained by addition polymerization of alkylene oxide using one or more compounds having two or more active hydrogen atoms as an initiator can be used.

Examples of the initiator include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, glycerin, trimethylolethane, Trimethylolpropane and the like can be used.

Further, as the alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, or the like can be used.

Further, as the polyol (a1), it is preferable to use a polyol having a hydrophilic group from the viewpoint of introducing a hydrophilic group into the urethane resin (A).

Examples of the polyol having a hydrophilic group include carboxyls such as 2,2′-dimethylolpropionic acid, 2,2′-dimethylolbutanoic acid, 2,2′-dimethylolbutyric acid, and 2,2′-dimethylolvaleric acid. A polyol having a sulfonic acid group such as 5-sulfoisophthalic acid, sulfoterephthalic acid, 4-sulfophthalic acid, and 5 [4-sulfophenoxy] isophthalic acid can be used. Examples of the polyol having a hydrophilic group include a polyester polyol having a hydrophilic group obtained by reacting the above-described polyol having a low molecular weight hydrophilic group with various polycarboxylic acids such as adipic acid. It can also be used.

The polyol having a hydrophilic group is preferably used in a range of 0.5% by mass to 10% by mass with respect to the total amount of the polyol (a1), and is used in a range of 1% by mass to 5% by mass. It is more preferable.

Examples of the polyisocyanate (a2) that can react with the polyol (a1) include aromatic polyisocyanates such as phenylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, polymethylene polyphenyl polyisocyanate, and carbodiimidized diphenylmethane polyisocyanate. Polyisocyanates having aliphatic or aliphatic cyclic structures such as isocyanate, hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, dimer acid diisocyanate, norbornene diisocyanate Etc. Alone in combination with the above use or two or may be used. Among them, it is preferable to use a polyisocyanate having an aliphatic cyclic structure, and it is more preferable to use isophorone diisocyanate or dicyclohexylmethane diisocyanate in order to prevent yellowing of the skin layer (C) over time. .

In the reaction between the polyol (a1) and the polyisocyanate (a2), the equivalent ratio [isocyanate group / hydroxyl group] of the hydroxyl group of the polyol (a1) and the isocyanate group of the polyisocyanate (a2) is 1.0. Is preferably in the range of ˜2.0, more preferably 1.1 to 1.9.

Examples of the chain extender (a3) that can be used include polyamines and hydroxyl group-containing compounds.

Examples of the polyamine include ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2,5-dimethylpiperazine, isophoronediamine, 4,4'-dicyclohexylmethanediamine, 3,3'- Diamines such as dimethyl-4,4′-dicyclohexylmethanediamine, 1,4-cyclohexanediamine; N-hydroxymethylaminoethylamine, N-hydroxyethylaminoethylamine, N-hydroxypropylaminopropylamine, N-ethylaminoethylamine, Diamines containing one primary amino group and one secondary amino group such as N-methylaminopropylamine; polyamines such as diethylenetriamine, dipropylenetriamine, triethylenetetramine; hydrazine, Hydrazines such as N, N'-dimethylhydrazine and 1,6-hexamethylenebishydrazine; Dihydrazides such as succinic acid dihydrazide, adipic acid dihydrazide, glutaric acid dihydrazide, sebacic acid dihydrazide, and isophthalic acid dihydrazide; β-semicarbazide propionic acid hydrazide Semicarbazides such as 3-semicarbazide-propyl-carbazate, semicarbazide-3-semicarbazide methyl-3,5,5-trimethylcyclohexane, and the like can be used.

Examples of the hydroxyl group-containing compound include ethylene glycol, diethylene recall, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, hexamethylene glycol, saccharose, methylene Glycols such as glycol, glycerin, sorbitol; phenols such as bisphenol A, 4,4′-dihydroxydiphenyl, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxydiphenylsulfone, hydrogenated bisphenol A, hydroquinone, and the like; Water or the like can be used alone or in combination of two or more within a range in which the storage stability of the urethane resin composition used in the present invention does not deteriorate.

The chain extender (a3) introduces a urea bond into the formed skin layer, and as a result, the urethane resin (A ) Is preferably used in the range of 1% by mass to 10% by mass, and more preferably in the range of 1% by mass to 5% by mass, based on the total amount of the raw materials used for the production of the above.

Examples of the organic solvent that can be used when the polyol (a1) and the polyisocyanate (a2) are reacted with the chain extender (a3) as necessary in the step 1 include ketones such as acetone and methyl ethyl ketone; Ethers such as tetrahydrofuran and dioxane; acetates such as ethyl acetate and butyl acetate; nitriles such as acetonitrile; amides such as dimethylformamide and N-methylpyrrolidone may be used alone or in combination of two or more. it can.

The urethane prepolymer obtained in Step 1 preferably has a functional group capable of reacting with the amino group of the polyalkanolamine in Step 2 at the molecular end. The functional group is preferably an isocyanate group.

The urethane prepolymer obtained in Step 1 may be a solvent-free type, but is preferably a type dissolved in the organic solvent from the viewpoint of imparting good handleability.

Next, the step 2 will be described.
Step 2 is a process in which the isocyanate group-containing urethane prepolymer obtained in Step 1 or an organic solvent solution thereof is mixed with polyalkanolamine and reacted to cause one or more urethane resins (A) to be obtained. In this step, two or more hydroxyl groups are introduced into the terminal.

Specifically, the desired urethane resin (A) is prepared by mixing the isocyanate group-containing urethane prepolymer or an organic solvent solution thereof or an aqueous dispersion thereof with polyalkanolamine and reacting the mixture at a room temperature of 25 ° C., for example. Can be manufactured. In that case, the amount of hydroxyl groups introduced into the urethane resin (A) to be obtained can be adjusted by adjusting the amount of polyalkanolamine used.

Examples of the polyalkanolamine (a4) include diethanolamine, 2-amino-1,3-propanediol, (R) -3-amino-1,2-propanediol, tris (hydroxymethyl) aminoethane, and 1-amino. An amine having a plurality of hydroxyl groups with respect to one amino group such as 1-deoxy-D-glucitol is used alone within a range in which the storage stability of the urethane resin composition used in the present invention is not lowered. Or 2 or more types can be used together.

The urethane resin composition for forming the skin layer used in the present invention may be a solventless type containing the urethane resin (A), from the viewpoint of imparting good coating workability, etc. It is preferable that it contains a solvent. As the solvent, an aqueous medium or various organic solvents can be used.

In addition, in using what contains the said urethane resin (A) and an aqueous medium (B) as a urethane resin composition for said skin layer formation, according to the said process 1 and the process 2, a urethane resin (A) or After producing the organic solvent solution and then neutralizing hydrophilic groups such as anionic groups in the urethane resin as necessary, an aqueous medium is supplied, and the urethane resin (A ) Is preferably dispersed. When mixing the urethane resin (A) and the aqueous medium, a machine such as a homogenizer may be used as necessary.

Examples of the aqueous medium (B) include water, organic solvents miscible with water, and mixtures thereof. Examples of the organic solvent miscible with water include alcohols such as methanol, ethanol, n- and isopropanol; ketones such as acetone and methyl ethyl ketone; polyalkylene glycols such as ethylene glycol, diethylene glycol and propylene glycol; Alkyl ethers; lactams such as N-methyl-2-pyrrolidone, and the like. In the present invention, only water may be used, a mixture of water and an organic solvent miscible with water may be used, or only an organic solvent miscible with water may be used. From the viewpoint of safety and load on the environment, water alone or a mixture of water and an organic solvent miscible with water is preferable, and only water is particularly preferable.

The aqueous medium (B) is preferably used in a range of 40% by mass to 85% by mass, and in a range of 50% by mass to 80% by mass with respect to the total amount of the urethane resin composition for forming the skin layer. More preferably it is used.

Examples of the organic solvent include ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran and dioxane; acetates such as ethyl acetate and butyl acetate; nitriles such as acetonitrile; dimethylformamide, N-methylpyrrolidone and the like. The amides can be used.

The urethane resin composition for forming the skin layer used in the present invention preferably contains the urethane resin (A) in the range of 10% by mass to 50% by mass with respect to the total amount of the urethane resin composition. The content of 20% by mass to 50% by mass is preferable for improving the coating workability.

From the viewpoint of forming the skin layer (C) excellent in durability such as excellent heat resistance (water), sweat resistance, oil resistance, hydrolysis resistance, etc., the urethane resin composition used in the present invention, A crosslinking agent can be used in combination.

As the crosslinking agent, conventionally known ones such as carbodiimide crosslinking agents, oxazoline crosslinking agents, epoxy crosslinking agents, isocyanate crosslinking agents, melamine crosslinking agents and the like can be used, and among them, carbodiimide crosslinking agents and oxazolines. It is preferable to use a crosslinking agent.

The crosslinking agent may be used in an amount of 1 to 10 parts by mass with respect to 100 parts by mass of the urethane resin (A) to improve durability such as heat resistance (water) resistance, sweat resistance and oil resistance. It is preferable in order to improve.

Moreover, the urethane resin composition for forming the skin layer used in the present invention may contain various additives in addition to the above-described ones. For example, additives such as associative thickeners, urethanization catalysts, silane coupling agents, fillers, thixotropic agents, tackifiers, waxes, heat stabilizers, light resistance stabilizers, fluorescent whitening agents, foaming agents, Thermoplastic resin, thermosetting resin, pigment, dye, conductivity imparting agent, antistatic agent, moisture permeability improver, water repellent, oil repellent, hollow foam, crystal water-containing compound, flame retardant, water absorbing agent, moisture absorption Agents, deodorants, foam stabilizers, antifoaming agents, antifungal agents, antiseptics, algaeproofing agents, pigment dispersants, antiblocking agents, and hydrolysis inhibitors can be used in combination.

As the associative thickener, for example, cellulose derivatives such as hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, polyacrylate, polyvinyl pyrrolidone, urethane, polyether, and the like can be used. Especially, since it has favorable compatibility with the said urethane resin (A), it is preferable to use a urethane type association type thickener. The associative thickener is preferably used in the range of 0.5% by mass to 5% by mass with respect to the total amount of the urethane resin (A).

The urethane resin composition is capable of forming a film having a sweat resistance level that does not cause poor appearance of leather-like sheets or peeling over time with respect to the support even when sweat or the like adheres. Therefore, it can be suitably used as a coating agent for forming a top coat layer of various substrates. In particular, it can be suitably used for forming the skin layer (C) constituting the leather-like sheet.

The urethane resin composition for forming the skin layer can be used as a material for forming the skin layer (C) constituting the leather-like sheet. The leather-like sheet generally has a skin layer (C) laminated on the surface of a support layer (E) made of a fibrous base material impregnated with a resin as necessary via an adhesive layer (D). The urethane resin composition used in the present invention can be suitably used for forming the skin layer (C). The leather-like sheet may have a porous layer (foamed layer) for the purpose of imparting flexibility and the like, and the adhesive layer (D) is foamed and substantially corresponds to the porous layer. You may do.

As the support that can be used for forming the support layer (E), a nonwoven fabric, a woven fabric, a knitted fabric, or the like can be used. As the material constituting the base material, for example, polyester fiber, nylon fiber, acrylic fiber, polyurethane fiber, acetate fiber, rayon fiber, polylactic acid fiber, cotton, hemp, silk, wool, blended fiber thereof or the like is used. can do.

The surface of the support may be subjected to antistatic processing, mold release processing, water repellent processing, water absorption processing, antibacterial deodorization processing, antibacterial processing, ultraviolet blocking processing, and the like as necessary.

The leather-like sheet in which the skin layer (C) is laminated on the surface of the support via the adhesive layer (D) is, for example, a urethane resin composition for forming the skin layer on a sheet subjected to a release treatment. The skin layer (C) is formed by applying and drying, and then the support is laminated on the skin layer (C) using an adhesive (d) or the like.

Examples of the method of applying the urethane resin composition on the sheet include a gravure coater method, a knife coater method, a pipe coater method, and a comma coater method. Further, as a method for drying and curing the urethane resin composition applied by the above method, for example, it is allowed to stand for 1 to 10 days at room temperature, or heated at a temperature of 50 to 250 ° C. for 1 to 600 seconds. The method of doing is mentioned.

Examples of the adhesive (d) used for bonding the skin layer (C) and the support layer (E) include a compound (d-1) having a hydroxyl group and a compound (d-2) having an isocyanate group. It is preferable to use the contained adhesive.

As the adhesive (d), it is preferable to use an adhesive containing the compound (d-2) having an isocyanate group in excess relative to the compound (d-1) having a hydroxyl group. As a result, the hydroxyl group of the compound (d-1) and the isocyanate group of the compound (d-2) react to form an adhesive layer (D), and the compound (d- 2) The isocyanate group of 2) reacts with part or all of the hydroxyl groups of the urethane resin (A) forming the skin layer (C), so that even if sweat or the like adheres, the appearance is poor. In addition, it is possible to obtain a leather-like sheet provided with a skin layer excellent in durability such as sweat resistance at a level that does not cause peeling over time from the support.

Regarding the use of an excessive amount of the compound (d-2), specifically, the isocyanate group of the compound (d-2) contained in the adhesive (d) and the compound (d-1) The equivalent ratio with the hydroxyl group [isocyanate group / hydroxyl group] is preferably in the range exceeding 1.0.

As the adhesive (d), specifically, a two-component adhesive containing a urethane resin having a hydroxyl group and a crosslinking agent having an isocyanate group can be used.

Examples of the urethane resin having a hydroxyl group that can be used for the adhesive (d) include the polyol (a1), polyisocyanate (a2), and chain extender (a3) exemplified as those usable for the production of the urethane resin (A). ) And the like, and those obtained by reacting them can be used.

When producing the urethane resin having the hydroxyl group, from the viewpoint of imparting a hydroxyl group capable of reacting with the isocyanate group of the crosslinking agent, the isocyanate group of the polyisocyanate used for the production and the hydroxyl group of the polyol It is preferable to use a product obtained by mixing and reacting the polyisocyanate and the polyol within the range where the equivalent ratio [isocyanate group / hydroxyl group] is less than 1.0.

The urethane resin having a hydroxyl group obtained above preferably has a weight average molecular weight of about 10,000 to 50,000 in order to exhibit excellent adhesive strength.

Further, as the adhesive (d), a two-component adhesive containing a polyol and a polyisocyanate can be used in addition to those described above.

The two-component adhesive can form an adhesive layer (D) in which urethane bonds are formed by mixing the polyol and polyisocyanate and then quickly applying the mixture onto the support surface.

As the polyol that can be used for the two-component adhesive, the same polyols (a1) exemplified as those that can be used when the urethane resin (A) is produced can be used. Specifically, polycarbonate polyol or the like can be used.

Moreover, as a polyisocyanate which can be used for the two-component adhesive, the same polyisocyanate (a2) exemplified as that usable when the urethane resin (A) is produced may be used. it can.

The two-component adhesive reacts with the hydroxyl group of the urethane resin (A) forming the skin layer (C), and even when sweat or the like adheres to it, the appearance or support of the leather-like sheet is poor. Equivalent ratio of the isocyanate group of the polyisocyanate and the hydroxyl group of the polyol in forming a skin layer (C) having durability such as sweat resistance at a level that does not cause peeling over time from the body It is preferable to use a mixture of the polyol and the polyisocyanate in such a range that [isocyanate group / hydroxyl group] exceeds 1.0.

As the adhesive (d), a urethane resin having a hydroxyl group as described above, a crosslinking agent having an isocyanate group, or a curing component such as polyol or polyisocyanate dispersed or dissolved in a solvent such as water or a solvent is used. It is possible to use a solvent-free type.

The adhesive (d) can be applied to the surface of the support (C) or the skin layer (C) by a method such as a gravure coater method, a knife coater method, a pipe coater method, or a comma coater method. . When the adhesive layer (D) is foamed to form a porous layer, the porous layer is formed by applying a method generally referred to as a mechanical foaming method, a microballoon, foaming, or the like when the adhesive (d) is applied to the support surface. It can form by making it foam by adding additives, such as an agent.

The adhesive layer (D) and the skin layer (C) are coated with the adhesive (d) and the skin layer (C) by heating them under the condition of 40 ° C. to 120 ° C. Even if the isocyanate group present in the adhesive (d) reacts with the hydroxyl group present in the skin layer (C) at the interface with (C) and sweat or the like adheres, It is possible to obtain a leather-like sheet having an outer skin layer having durability such as sweat resistance and oil resistance at a level that does not cause poor appearance of the leather-like sheet and peeling over time with respect to the support.

Further, when an intermediate layer such as a porous layer is provided as the leather-like sheet in addition to the adhesive layer (D), for example, the urethane resin composition for forming the skin layer on a sheet subjected to a release treatment. A skin layer (C) is formed by coating and drying, and then a porous layer forming resin composition foamed by a conventionally known mechanical foaming method or water foaming method on the skin layer (C). It can be obtained by forming a porous layer by coating and curing, and then laminating the support (C) on the porous layer using the adhesive (d).

The thickness of the skin layer (C) constituting the leather-like sheet obtained above is preferably in the range of about 10 μm to 300 μm. The adhesive layer (D) preferably has a thickness of 10 μm to 300 μm.

The leather-like sheet obtained by the above method is excellent in bending resistance, including durability such as sweat resistance and oil resistance, and is used for various applications such as bags, shoes, clothes, and vehicle interior materials. It is possible.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.

[Preparation Example 1] Preparation of adhesive (d1-1) In the presence of 1221 g of methyl ethyl ketone and 0.1 g of stannous octylate, 1000 g of polycarbonate diol (Niporan N980R; Nippon Polyurethane Industry Co., Ltd .: number average molecular weight 2000); By reacting 34 g of dimethylolpropionic acid and 187 g of dicyclohexylmethane diisocyanate (HMDI) at 70 ° C. until the isocyanate group disappeared, a methyl ethyl ketone solution of a urethane resin having a hydroxyl group at the terminal was obtained.

After mixing 2462 g of the methyl ethyl ketone solution of the urethane resin and 25 g of triethylamine, the mixture was mixed with 2442 g of pure water and phase-inversion emulsified to obtain an emulsion.

Next, by distilling off methyl ethyl ketone from the emulsion, a urethane resin composition [d1-1-1] having a nonvolatile content of 45% by mass was obtained.

100 g of the urethane resin composition [d1-1-1] obtained above, 0.2 g of silicone leveling agent, 0.1 g of silicone antifoaming agent, 1.0 g of urethane associative thickener, isocyanate crosslinking agent 5.0 g was added, stirred at 2000 rpm for 2 minutes using a mechanical mixer, and then defoamed using a vacuum defoamer to obtain an aqueous adhesive (d1-1).

[Preparation Example 2] Preparation of adhesive (d1-2) Polycarbonate diol heated to 80 ° C. in the presence of 0.1 g of stannous octylate in a nitrogen atmosphere (Niporan N980R; Nippon Polyurethane Industry Co., Ltd .: Number average A solvent-free adhesive (d1-2) was obtained by stirring 100 g of molecular weight 2000) and 14 g of dicyclohexylmethane diisocyanate (HMDI) using a mechanical mixer at 2000 rpm for 2 minutes and then defoaming using a vacuum defoamer. .

[Example 1] Preparation of leather-like sheet In the presence of 710 g of methyl ethyl ketone and 0.1 g of stannous octylate, 1000 g of polycarbonate diol (Niporan N981; Nippon Polyurethane Industry Co., Ltd .: number average molecular weight 1000) and dimethylolpropionic acid 67 g and 590 g of dicyclohexylmethane diisocyanate (HMDI) are reacted at 70 ° C. until the NCO% reaches 2.7% by mass to obtain a methyl ethyl ketone solution of the terminal isocyanate group-containing urethane prepolymer (A′-1). It was. The NCO% is the ratio of the mass of isocyanate groups possessed by polyisocyanate to the total mass of raw materials used in the production of the polyurethane.

After mixing 2367 g of a methyl ethyl ketone solution of the terminal isocyanate group-containing urethane prepolymer (A′-1) and 50 g of triethylamine, the mixture was mixed with 2367 g of pure water and phase-emulsified to obtain an emulsion.

The resulting emulsion was supplied with 1310 g of a chain extender aqueous solution containing 36 g of ethylenediamine and 95 g of diethanolamine, and mixed to cause a chain elongation reaction.

Next, by distilling off methyl ethyl ketone from the reaction mixture, a urethane resin composition [I] (weight average molecular weight 42000, hydroxyl value 56.7) having a nonvolatile content of 35% by mass was obtained.

100 g of the urethane resin composition [I] obtained above, 0.2 g of the silicone leveling agent, 0.1 g of the silicone antifoaming agent, and 1.0 g of the urethane-based associative thickener are added, and 2000 rpm using a mechanical mixer. The mixture was stirred for 2 minutes and then defoamed using a vacuum defoamer to obtain a urethane resin composition [I-1] for forming a skin layer.

100 parts by mass of the urethane resin composition [I-1] for forming the skin layer was applied on a release paper (155T Flat Flat Nihon Printing Co., Ltd.) so that the film thickness after application was 150 μm. .

Immediately after the application, by pre-drying at 70 ° C. for 2 minutes using a Warner Mathis (dryer) and then drying at 120 ° C. for 2 minutes, by completely evaporating the water contained in the application layer, A polyurethane resin film was obtained.

On the polyurethane resin film obtained by the above method, 100 parts by mass of the adhesive (d1-1) obtained in Preparation Example 1 was applied so that the film thickness was 150 μm, and then Warner Mathis (dryer) was applied. Used and dried at 70 ° C. for 2 minutes.

After the drying, a support made of a polyester fiber nonwoven fabric was placed on the coated surface of the adhesive (d1-1), pressure-bonded using a roll adjusted to 120 ° C., and then aged at 80 ° C. for 24 hours. After the aging, the release paper was removed to obtain a leather-like sheet [I-2].

[Example 2] Production of leather-like sheet On the other hand, 100 parts by mass of the urethane resin composition [I-1] for forming the skin layer used in Example 1 above was separated from release paper (155T Flat Dai Nippon Printing Co., Ltd.). The film thickness after application was 150 μm.

Immediately after the application, by pre-drying at 70 ° C. for 2 minutes using a Warner Mathis (dryer) and then drying at 120 ° C. for 2 minutes, by completely evaporating the water contained in the application layer, A polyurethane resin film was obtained.

On the polyurethane resin film obtained by the above method, 100 parts by mass of the adhesive (d1-2) obtained in Preparation Example 2 was applied so that the film thickness was 150 μm. Further, a support made of a polyester fiber nonwoven fabric was placed on the surface to which the adhesive (d1-2) was applied, pressure-bonded using a roll adjusted to 120 ° C., and then aged at 80 ° C. for 24 hours. After the aging, the release paper was removed to obtain a leather-like sheet [II-2].

[Example 3] Preparation of leather-like sheet In the presence of 710 g of methyl ethyl ketone and 0.1 g of stannous octylate, 1000 g of polyester diol (Placcel 210, Daicel Chemical Industries, Ltd. molecular weight of about 1000), 67 g of dimethylolpropionic acid, By reacting 590 g of dicyclohexylmethane diisocyanate (HMDI) at 70 ° C. until NCO% reached 2.7% by mass, a methyl ethyl ketone solution of the terminal isocyanate group-containing urethane prepolymer (A′-2) was obtained.

After mixing 50 g of triethylamine with 2367 g of the methyl ethyl ketone solution of this urethane prepolymer (A′-2), it was mixed with 2367 g of pure water and phase-inverted and emulsified to obtain an emulsion.

The resulting emulsion was supplied with 1310 g of a chain extender aqueous solution containing 36 g of ethylenediamine and 95 g of diethanolamine, and mixed to cause a chain elongation reaction.

Next, by distilling off methyl ethyl ketone from the reaction mixture, a urethane resin composition [II] (weight average molecular weight 41000, hydroxyl value 56.7) having a nonvolatile content of 35% by mass was obtained.

100 g of the urethane resin composition [II] obtained above, 0.2 g of silicone leveling agent, 0.1 g of silicone antifoaming agent and 1.0 g of urethane associative thickener are added, and 2000 rpm using a mechanical mixer. The mixture was stirred for 2 minutes and then defoamed using a vacuum defoamer to obtain a urethane resin composition [II-2] for forming a skin layer.

Example 1 except that 100 parts by mass of the urethane resin composition for skin layer formation [II-1] was used instead of the urethane resin composition for skin layer formation [I-1]. The leather-like sheet [III-2] was obtained by this method.

[Example 4] Production of leather-like sheet In the presence of 710 g of methyl ethyl ketone and 0.1 g of stannous octylate, 1000 g of polycarbonate diol (Niporan N981; Nippon Polyurethane Industry Co., Ltd .: number average molecular weight 1000) and polyethylene glycol (PEG1000) , NOF Corporation) 50 g, polyethylene glycol monomethyl ether (Uniox M1000: NOF Corporation) 50 g, and dicyclohexylmethane diisocyanate (HMDI) 590 g until NCO% reaches 2.7% by mass. A methyl ethyl ketone solution of the terminal isocyanate group-containing urethane prepolymer (A'-3) was obtained by reacting at 0 ° C.

By mixing 2400 g of a 10% by weight aqueous solution of an emulsifier (Newcol 2314: Nippon Emulsifier Co., Ltd.) in 2400 g of the methyl isocyanate solution of the terminal isocyanate group-containing urethane prepolymer (A′-3) An emulsion was obtained.

The resulting emulsion was supplied with 1310 g of a chain extender aqueous solution containing 36 g of ethylenediamine and 95 g of diethanolamine, and mixed to cause a chain elongation reaction.

Next, by distilling off methyl ethyl ketone from the reaction mixture, a urethane resin composition [III] (weight average molecular weight 43,000, hydroxyl value 55.7) having a nonvolatile content of 35% by mass was obtained.

100 g of the urethane resin composition [III] obtained above, 0.2 g of silicone leveling agent, 0.1 g of silicone antifoaming agent and 1.0 g of urethane associative thickener are added, and 2000 rpm using a mechanical mixer. The mixture was stirred for 2 minutes and then defoamed using a vacuum defoamer to obtain a urethane resin composition [III-1] for forming a skin layer.

Example 1 except that 100 parts by mass of the urethane resin composition for forming the skin layer [III-1] is used instead of the urethane resin composition for forming the skin layer [I-1]. By the method, a leather-like sheet [IV-2] was obtained.

[Example 5] Production of leather-like sheet In the presence of 630 g of methyl ethyl ketone and 0.1 g of stannous octylate, 1000 g of polycarbonate diol (Niporan N980R; Nippon Polyurethane Industry Co., Ltd .: number average molecular weight 2000) and dimethylolpropionic acid By reacting 67 g and 390 g of dicyclohexylmethane diisocyanate (HMDI) at 70 ° C. until the NCO% reaches 2.0% by mass, a methyl ethyl ketone solution of the terminal isocyanate group-containing urethane prepolymer (A′-4) is obtained. It was.

After mixing 2087 g of the methyl isocyanate solution of the terminal isocyanate group-containing urethane prepolymer (A′-4) and 50 g of triethylamine, the mixture was mixed with 2367 g of pure water and phase-inverted and emulsified to obtain an emulsion.

The obtained emulsion was supplied with 770 g of a chain extender aqueous solution containing 24 g of ethylenediamine and 53 g of diethanolamine, and mixed to cause a chain elongation reaction.

Then, methyl ethyl ketone was distilled off from the reaction mixture to obtain a urethane resin composition [IV] (weight average molecular weight 42000, hydroxyl value 36.8) having a nonvolatile content of 35% by mass.

100 g of the urethane resin composition [IV] obtained above, 0.2 g of a silicone leveling agent, 0.1 g of a silicone antifoaming agent, and 1.0 g of a urethane-based associative thickener are added, and 2000 rpm using a mechanical mixer. By stirring for 2 minutes and then defoaming using a vacuum defoamer, a urethane resin composition [IV-1] for forming the skin layer was obtained. Urethane resin composition for forming the skin layer [I- A leather-like sheet [V-2] was obtained in the same manner as in Example 1 except that 100 parts by mass of the urethane resin composition [IV-1] for forming the skin layer was used instead of 1]. .

[Example 6] Production of leather-like sheet In the presence of 710 g of methyl ethyl ketone and 0.1 g of stannous octylate, 1000 g of polycarbonate diol (Niporan N981; Nippon Polyurethane Industry Co., Ltd .: number average molecular weight 1000) and dimethylolpropionic acid 67 g and 590 g of dicyclohexylmethane diisocyanate (HMDI) are reacted at 70 ° C. until the NCO% reaches 2.7% by mass to obtain a methyl ethyl ketone solution of the terminal isocyanate group-containing urethane prepolymer (A′-1). It was.

After mixing 2367 g of a methyl ethyl ketone solution of the terminal isocyanate group-containing urethane prepolymer (A′-1) and 50 g of triethylamine, the mixture was mixed with 2367 g of pure water and phase-emulsified to obtain an emulsion.

The resulting emulsion was supplied with 530 g of a chain extender solution containing 42 g of ethylenediamine and 11 g of diethanolamine, and mixed to cause a chain extension reaction.

Next, by distilling off methyl ethyl ketone from the reaction mixture, a urethane resin composition [V] (weight average molecular weight 42000, hydroxyl value 6.9) having a nonvolatile content of 35% by mass was obtained.

100 g of the urethane resin composition [V] obtained above, 0.2 g of the silicone leveling agent, 0.1 g of the silicone antifoaming agent, and 1.0 g of the urethane associative thickener are added, and 2000 rpm using a mechanical mixer. By stirring for 2 minutes and then defoaming using a vacuum defoamer, a urethane resin composition [V-1] for forming the skin layer was obtained. Urethane resin composition for forming the skin layer [I- A leather-like sheet [V-2] was obtained in the same manner as in Example 1 except that 100 parts by mass of the urethane resin composition for forming a skin layer [V-1] was used instead of 1]. .

[Comparative Example 1] Preparation of leather-like sheet In the presence of 710 g of methyl ethyl ketone and 0.1 g of stannous octylate, 1000 g of polycarbonate diol (Niporan N981; Nippon Polyurethane Industry Co., Ltd .: number average molecular weight 1000) and dimethylolpropionic acid 67 g and 590 g of dicyclohexylmethane diisocyanate (HMDI) are reacted at 70 ° C. until the NCO% reaches 2.7% by mass to obtain a methyl ethyl ketone solution of the terminal isocyanate group-containing urethane prepolymer (A′-1). It was.

After mixing 2367 g of a methyl ethyl ketone solution of the terminal isocyanate group-containing urethane prepolymer (A′-1) and 50 g of triethylamine, the mixture was mixed with 2367 g of pure water and phase-emulsified to obtain an emulsion.

The obtained emulsion was supplied with 910 g of a chain extender aqueous solution containing 36 g of ethylenediamine and 55 g of monoethanolamine, and mixed to cause a chain extension reaction.

Subsequently, by distilling off methyl ethyl ketone from the reaction mixture, a urethane resin composition [I ′] (weight average molecular weight 39000, hydroxyl value 28.9) having a nonvolatile content of 35% by mass was obtained.

Add 100 g of the urethane resin composition [I ′] obtained above, 0.2 g of silicone leveling agent, 0.1 g of silicone antifoaming agent, and 1.0 g of urethane associative thickener, and use a mechanical mixer. By stirring at 2000 rpm for 2 minutes and then defoaming using a vacuum defoamer, a urethane resin composition [I′-1] for forming a skin layer was obtained.

Example 1 except that 100 parts by mass of the urethane resin composition [I′-1] for forming the skin layer was used instead of the urethane resin composition [I-1] for forming the skin layer. A leather-like sheet [I'-2] was obtained by the method described above.

[Comparative Example 2] Preparation of leather-like sheet In the presence of 710 g of methyl ethyl ketone and 0.1 g of stannous octylate, 1000 g of polycarbonate diol (Niporan N981; Nippon Polyurethane Industry Co., Ltd .: number average molecular weight 1000) and dimethylolpropionic acid 67 g and 590 g of dicyclohexylmethane diisocyanate (HMDI) are reacted at 70 ° C. until the NCO% reaches 2.7% by mass to obtain a methyl ethyl ketone solution of the terminal isocyanate group-containing urethane prepolymer (A′-1). It was.

After mixing 2367 g of a methyl ethyl ketone solution of the terminal isocyanate group-containing urethane prepolymer (A′-1) and 50 g of triethylamine, the mixture was mixed with 2367 g of pure water and phase-emulsified to obtain an emulsion.

The obtained emulsion was supplied with 520 g of a chain extender aqueous solution containing 21 g of N- (aminoethyl) ethanolamine and 31 g of monoethanolamine, and mixed to cause a chain elongation reaction.

Next, by distilling off methyl ethyl ketone from the reaction mixture, a urethane resin composition [II ′] (weight average molecular weight 40000, hydroxyl value 23, 2) having a nonvolatile content of 35% by mass was obtained.

Add 100 g of the urethane resin composition [II ′] obtained above, 0.2 g of silicone leveling agent, 0.1 g of silicone antifoaming agent, and 1.0 g of urethane associative thickener, and use a mechanical mixer. By stirring at 2000 rpm for 2 minutes and then defoaming using a vacuum defoamer, a urethane resin composition [II′-1] for forming a skin layer was obtained.

Example 1 except that 100 parts by mass of the urethane resin composition for forming the skin layer [II′-1] is used instead of the urethane resin composition for forming the skin layer [I-1]. A leather-like sheet [II′-2] was obtained by the method described above.

Comparative Example 3 Production of Leather-Like Sheet In the presence of 710 g of methyl ethyl ketone and 0.1 g of stannous octylate, 1000 g of polycarbonate diol (Niporan N981; Nippon Polyurethane Industry Co., Ltd .: number average molecular weight 1000) and dimethylolpropionic acid 67 g and 590 g of dicyclohexylmethane diisocyanate (HMDI) are reacted at 70 ° C. until the NCO% reaches 2.7% by mass to obtain a methyl ethyl ketone solution of the terminal isocyanate group-containing urethane prepolymer (A′-1). It was.

After mixing 2367 g of a methyl ethyl ketone solution of the terminal isocyanate group-containing urethane prepolymer (A′-1) and 50 g of triethylamine, the mixture was mixed with 2367 g of pure water and phase-emulsified to obtain an emulsion.

The obtained emulsion was supplied with 1400 g of an aqueous chain extender solution containing 36 g of ethylenediamine and 116 g of dibutylamine, and mixed to cause a chain extension reaction.

Next, by distilling off methyl ethyl ketone from the reaction mixture, a urethane resin composition [III ′] (weight average molecular weight 39000, hydroxyl value 0.0) having a nonvolatile content of 35% by mass was obtained.

Add 100 g of the urethane resin composition [III ′] obtained above, 0.2 g of silicone leveling agent, 0.1 g of silicone antifoaming agent, and 1.0 g of urethane associative thickener, and use a mechanical mixer. The mixture was stirred at 2000 rpm for 2 minutes, and then defoamed using a vacuum defoamer to obtain a urethane resin composition [III′-1] for forming a skin layer.

Example 1 except that 100 parts by mass of the urethane resin composition for forming the skin layer [III′-1] is used instead of the urethane resin composition for forming the skin layer [I-1]. A leather-like sheet [III'-2] was obtained by the method described above.

[Adhesion evaluation method]
A 1-inch wide hot-melt cloth tape (manufactured by Sun Kasei Co., Ltd.) was adhered to the surface of the skin layer constituting the leather-like sheet obtained in Examples and Comparative Examples at 130 ° C. for 5 seconds, and then JIS K6854- 2 was measured using Tensilon (head speed = 200 mm / min) at a temperature of 23 ° C. and a relative humidity of 65%. If the peel strength of the skin layer constituting the leather-like sheet was 3.0 kg / cm or more, it was judged that the skin layer had practically sufficient adhesion to the support.

[Sweating Resistance Evaluation Method 1 (Sweat Resistance 1)]
It heated at 80 degreeC for 24 hours in the state which mounted the filter paper which soaked the oleic acid of the same mass as the dry filter paper on the skin layer which comprises the leather-like sheet | seat obtained in the said Example and the comparative example.

After heating, the filter paper was removed, and oleic acid adhering to the surface of the skin layer was wiped off with waste cloth.

The surface of the skin layer after wiping was visually observed and evaluated according to the following evaluation criteria.

A: No change in appearance and no peeling of the skin layer compared to before oleic acid was adhered.

B: Slight swelling (swelling of the skin layer) was observed in a small part of the appearance compared to before oleic acid was attached, but it was at a level that was practically acceptable and peeling of the skin layer was also observed. There wasn't.

C: Swelling (swelling of the skin layer) that can be clearly confirmed in appearance was observed as compared with that before the oleic acid was adhered, but peeling of the skin layer was not observed.

D: Swelling (swelling of the skin layer) that can be clearly confirmed in appearance was seen and partial peeling of the skin layer was seen compared to before oleic acid was adhered.

E: Most of the skin layer was peeled off or dissolved.

[Evaluation method 2 of sweat resistance (sweat resistance 2)]
The leather-like sheets obtained in the examples and comparative examples were immersed in oleic acid and left in an environment of 25 ° C. for 3 days.

After leaving, the gauze was removed, and the oleic acid adhering to the surface of the epidermis layer was wiped off with waste cloth.

The leather-like sheet after wiping is dried in an environment of 90 ° C. for 1 hour, the leather-like sheet is fixed horizontally, a canvas is placed on the surface of the skin layer, and a weight of 500 g is applied. Then, the surface of the skin layer was repeatedly rubbed.

Evaluation was performed according to the following evaluation criteria based on the number of frictions during the rubbing and the appearance of the skin layer. A material having the above evaluation of “C” or higher is practically preferable, and is preferably “B” or higher.

The specific number of frictions is unknown. (For checking every 1000 times)
A: The number of friction was 5000 times, and the skin layer of the leather-like sheet was not peeled off.
B: The skin layer of the leather-like sheet was peeled off when the number of friction was 5000, and the base material was exposed.
C: The skin layer of the leather-like sheet was peeled off when the number of frictions was 4000, and the base material was exposed.
D: The skin layer of the leather-like sheet was peeled off when the number of frictions was 3000, and the base material was exposed.
E: The skin layer of the leather-like sheet was peeled off and the substrate was exposed before rubbing or within 5 times of rubbing.

[Evaluation method of oil resistance]
On the skin layer constituting the leather-like sheet obtained in the above-mentioned Examples and Comparative Examples, a filter paper impregnated with sun oil (BUG SUN; COPPERTORN) having the same mass as that of the dry filter paper was placed. Heated at 70 ° C. for hours.

After heating, the filter paper was removed, and the sun oil adhering to the surface of the skin layer was wiped off with a waste cloth.

The surface of the skin layer after wiping was visually observed and evaluated according to the following evaluation criteria.

A: Compared with before the sun oil was adhered, the appearance was not changed at all, and the skin layer was not peeled off.
B: Slight swelling (swelling of the skin layer) was observed in a small part of the appearance compared to before the sun oil was applied, but this was a practically acceptable level and peeling of the skin layer was also observed. There wasn't.
C: Although swelling (swelling of the skin layer) that can be clearly confirmed was observed in appearance as compared with before the sun oil was adhered, peeling of the skin layer was not observed.
D: Swelling (swelling of the skin layer) that can be clearly confirmed in appearance was observed and partial peeling of the skin layer was observed as compared to before the sun oil was adhered.
E: Most of the epidermis layer peeled or dissolved.

[Bend resistance evaluation method]
Using a bending tester (flexometer), the number of times until a crack occurred on the surface of the leather-like sheet under the condition of −10 ° C. was measured.

The specific number of flexions is unknown. (For checking every specified number of times)
A: Cracks did not occur on the surface of the leather-like sheet when the number of bendings was 100,000.
B: Cracks occurred on the surface of the leather-like sheet when the number of flexions was 75,000.
C: Cracks occurred on the surface of the leather-like sheet when the number of flexing was 50000 times.
D: Cracks occurred on the surface of the leather-like sheet when the number of flexing was 25000 times.
E: Cracks occurred on the surface of the leather-like sheet when the number of bendings was 10,000.

The leather-like sheets obtained in Examples 1 and 2 each had a skin layer excellent in sweat resistance and oil resistance, and did not cause cracking even when bent. Further, the leather-like sheets obtained in Example 3 and Example 4 did not contain a polycarbonate structure, or the ratio of the polycarbonate structure was small. As well as excellent oil resistance and bending resistance. Further, the leather-like sheet obtained in Example 5 had good sweat resistance, oil resistance, and flex resistance, although the hydroxyl value of the urethane resin constituting the skin layer was slightly reduced. .

On the other hand, the leather-like sheet obtained in Comparative Examples 1 and 2 is an example in which a urethane resin having one hydroxyl group at one end is used as the urethane resin constituting the skin layer, and is sweat and oil resistant. Caused a significant decline. Moreover, the leather-like sheet obtained in Comparative Example 3 is an example in which a urethane resin having no hydroxyl group at the terminal is used as the urethane resin constituting the skin layer, and the sweat resistance and oil resistance are significantly reduced. Caused.

Claims (5)

A skin layer (C) formed by using a urethane resin composition containing at least one hydroxyl group at one end and a urethane resin (A) containing an aqueous medium (B), and an adhesive layer (D) And a leather-like sheet | seat characterized by having a support body layer (E). The urethane resin (A) is a urethane prepolymer having isocyanate groups at both ends by reacting a polyol (a1) containing a polycarbonate polyol, a polyisocyanate (a2), and a chain extender (a3) if necessary. The leather-like sheet according to claim 1, which is obtained by obtaining a polymer and then reacting the isocyanate group of the urethane prepolymer with the amino group of the polyalkanolamine. 2. The adhesive layer (D) is formed using an adhesive (d) containing a compound (d-1) having a hydroxyl group and a compound (d-2) having an isocyanate group. A leather-like sheet as described in 1. 4. A part or all of isocyanate groups of the compound (d-2) and a hydroxyl group of the urethane resin (A) contained in the skin layer (E) react to form a urethane bond. A leather-like sheet as described in 1. On the release paper, a urethane resin composition containing at least one hydroxyl group at one end (A) and a urethane resin composition containing an aqueous medium (B) is applied and dried, and then applied to the application surface. A method for producing a leather-like sheet, wherein the adhesive (d) is applied, and then a support is placed on the application surface of the adhesive (d) and heated.