Aqueous surface treatment agent for vinyl chloride-based resin leather and vinyl chloride-based resin leather subjected to surface treatment using the same

Abstract

To provide a PVC leather aqueous surface treatment agent that is an aqueous surface treatment agent for treating the surface of a leather base material having a surface containing vinyl chloride-based resin (PVC) and enables the manufacture of a PVC leather excellent in abrasion resistance, rubbing resistance, and alcohol resistance by suppressing migration of a plasticizer contained in the base material surface including PVC.SOLUTION: A vinyl chloride-based resin leather aqueous surface treatment agent includes: a chain extended product by (D) polyamine having two or more amino groups and / or imino groups of isocyanate group terminal prepolymer as a reaction product of (A) organic polyisocyanate, (B) polyol, and (C) polyalcohol; or a chain extended product by (D) polyamine having two or more amino groups and / or imino groups of neutralized product of isocyanate group terminal prepolymer as a reaction product of (A) organic polyisocyanate, (B) polyol, (E) compound having anionic hydrophilic group and at least two active hydrogens, and (C) polyalcohol. The (B) polyol includes polycarbonate diol constituted only of (B1) diol having straight-chain structure with even number in 4 to 10 of carbon number. The (C) polyalcohol includes polyalcohol having at least three or more active hydrogens.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an aqueous surface treatment agent for vinyl chloride resin leather and vinyl chloride resin leather surface-treated with the same. [Background technology]

[0002] In the manufacturing process of synthetic leather having a surface layer made of a thermosetting or thermoplastic polyurethane resin, or synthetic leather in which at least the surface of the base material contains a polyvinyl chloride resin (hereinafter also referred to as "PVC leather"), a surface treatment agent is used to improve the abrasion resistance and matteness of the surface of the synthetic leather. The resin compositions used in conventional surface treatment agents are mainly solvent-based, containing organic solvents such as dimethylformamide, toluene, and methyl ethyl ketone, but these organic solvents are often highly flammable and highly toxic, which causes problems such as fire hazards, deterioration of the working environment, and environmental pollution of the air and water. In addition, in the manufacturing of synthetic leather, these organic solvents are also recovered, but this has the problem of requiring a large amount of cost and labor.

[0003] In recent years, not only has environmental regulations become more stringent, but the organic solvents remaining inside synthetic leather obtained using organic solvent-based surface treatment agents have also become a problem, as they may have adverse effects on the human body, such as skin disorders. For this reason, development of aqueous surface treatment agents that contain as little or no organic solvent as possible has been promoted, and in particular, for leather materials for synthetic leather used in automobile interior materials, there is a strong demand for aqueous surface treatment agents, as there are concerns about the adverse effects of residual organic solvents on the human body.

[0004] In particular, the demand for PVC leather is growing from the viewpoint of cost compared to synthetic leather having a surface layer made of thermosetting or thermoplastic polyurethane resin, but since PVC leather has poor abrasion resistance, high abrasion resistance is required for the aqueous surface treatment agent used. In addition, since PVC contains a plasticizer, there are problems such as the plasticizer bleeding out over time and increasing gloss. Furthermore, in recent years, the surface of interior materials has been increasingly wiped with alcohol, and durability against alcohol is also required, but in PVC leather, there is a problem that the adhesion between the substrate surface containing PVC and the surface treatment layer formed by the aqueous surface treatment agent is insufficient, and the surface treatment layer is prone to peeling, whitening, etc.

[0005] For example, International Publication No. 2019 / 221088 (Patent Document 1) describes a polyurethane resin containing a polyol component and an isocyanate component, in which (1) the polyol component contains a polycarbonate diol component and the isocyanate component contains a linear aliphatic isocyanate component, (2) the polycarbonate diol component has a number average molecular weight of 500 to 3000 and contains a diol-derived structure having 3 to 10 carbon atoms in its structure, and (3) 10 mol% or more of the isocyanate component is a linear aliphatic isocyanate component having 4 to 10 carbon atoms. The polyurethane resin is also described as a paint, and synthetic imitation leather containing the paint on its surface is described. In particular, in the examples of Patent Document 1, a synthetic imitation leather is described in which a PVC sheet is surface-treated with a surface treatment agent containing a polyurethane resin produced using a polycarbonate diol derived from 1,4-butanediol and 1,10-decanediol as the polycarbonate diol component, and it is also described that this synthetic imitation leather has both excellent cold bending resistance and chemical resistance.

[0006] In addition, WO 2022 / 097332 (Patent Document 2) describes a laminate produced by coating a PVC substrate with an aqueous polyurethane resin composition prepared using a polycarbonate polyol made from 1,9-nonanediol and 2-methyl-1,8-octanediol, and also describes that this laminate has excellent adhesion and bleeding resistance.

[0007] Furthermore, International Publication No. 2022 / 097333 (Patent Document 3) describes a laminate produced by coating a PVC substrate with an aqueous polyurethane resin composition prepared using polycarbonate polyol derived from 1,6-hexanediol and polytetramethylene glycol, and also describes that this laminate has excellent adhesion and bleeding resistance. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] International Publication No. 2019 / 221088 [Patent Document 2] International Publication No. 2022 / 097332 [Patent Document 3] International Publication No. 2022 / 097333 Summary of the Invention [Problem to be solved by the invention]

[0009] However, the synthetic imitation leathers or leathers described in any of Patent Documents 1 to 3 were not necessarily sufficient in abrasion resistance, resistance to plasticizer migration, and alcohol resistance.

[0010] The present invention has been made in consideration of the problems associated with the above-mentioned prior art, and has an object to provide an aqueous surface treatment agent for treating the surface of a leather substrate having a surface containing PVC, which inhibits migration of a plasticizer contained in the PVC-containing substrate surface (e.g., a PVC-containing skin layer) and enables the production of PVC leather that has excellent abrasion resistance, crumple resistance, and alcohol resistance, as well as PVC leather that has been surface-treated with this aqueous surface treatment agent for PVC leather. [Means for solving the problem]

[0011] As a result of intensive research conducted by the present inventors to achieve the above object, it was discovered that by treating the surface of a leather substrate having a PVC-containing surface with an aqueous surface treatment agent containing an isocyanate-terminated prepolymer or a chain-extended product of its neutralization, which is synthesized by combining a polyol containing a polycarbonate diol composed only of diols having a linear structure with an even carbon number of 4 to 10 and a polyhydric alcohol having at least 3 or more active hydrogens, migration of plasticizers in the PVC leather can be suppressed and the PVC leather can be endowed with excellent abrasion resistance, rubbing resistance, and alcohol resistance, thereby completing the present invention.

[0012] That is, the present invention provides the following aspects. [1] An aqueous surface treatment agent for treating a surface of a leather substrate having a surface containing a vinyl chloride resin, comprising: The aqueous surface treatment agent is (D) a chain extension product of an isocyanate-terminated prepolymer, which is a reaction product of (A) an organic polyisocyanate, (B) a polyol, and (C) a polyhydric alcohol, with a polyamine having two or more amino groups and / or imino groups; or (A) an organic polyisocyanate; (B) a polyol; (E) a compound having an anionic hydrophilic group and at least two active hydrogen atoms; and (C) a polyhydric alcohol. The neutralized prepolymer isocyanate-terminated, and the prepolymer is chain-extended by (D) a polyamine having two or more amino groups and / or imino groups. Including, The (B) polyol contains (B1) a polycarbonate diol composed only of a diol having a linear structure and an even number of carbon atoms of 4 to 10, The (C) polyhydric alcohol contains a polyhydric alcohol having at least three active hydrogens. A water-based surface treatment agent for vinyl chloride resin leather. [2] The aqueous surface treatment agent for vinyl chloride resin leather according to [1], wherein the proportion of the (B1) polycarbonate diol in the (B) polyol is 40 mass% or more. [3] The proportion of the (C) polyhydric alcohol is In the case where the chain extension product is a chain extension product of the isocyanate group-terminated prepolymer, the amount of the chain extension product is, relative to the total amount of the (B) polyol and the (C) polyhydric alcohol, In the case where the chain extension product is a chain extension product of a neutralization product of the isocyanate group-terminated prepolymer, the amount of the chain extension product is, relative to the total amount of the (B) polyol, the (C) polyhydric alcohol, and the (E) compound having an anionic hydrophilic group and at least two active hydrogens, The aqueous surface treatment agent for vinyl chloride resin leather according to [1] or [2], wherein the content is 0.1 to 1.5% by mass. [4] The aqueous surface treatment agent for vinyl chloride resin leather according to any one of [1] to [3], wherein the content of free isocyanate groups in the isocyanate group-terminated prepolymer is 0.2 to 4.0 mass %. [5] The aqueous surface treatment agent for vinyl chloride resin leather according to [1] to [4], wherein the (A) organic polyisocyanate is at least one selected from the group consisting of aliphatic polyisocyanates and alicyclic polyisocyanates. [6] A vinyl chloride resin leather comprising a surface treatment layer formed on the vinyl chloride resin-containing surface of a leather substrate having a vinyl chloride resin-containing surface using the aqueous surface treatment agent for vinyl chloride resin leather described in any one of [1] to [5]. Effect of the Invention

[0013] According to the present invention, a leather substrate having a surface containing PVC is provided, and migration of a plasticizer contained in the PVC-containing substrate surface (e.g., a skin layer containing PVC) is suppressed, making it possible to obtain PVC leather having excellent abrasion resistance, crumple resistance, and alcohol resistance. [Brief description of the drawings]

[0014] [Figure 1] 1 is a cross-sectional view showing one embodiment of the vinyl chloride resin leather of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view showing another embodiment of the vinyl chloride resin leather of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The present invention will be described in detail below based on preferred embodiments thereof.

[0016] [Water-based surface treatment agent for PVC leather] First, the aqueous surface treatment agent for PVC leather of the present invention will be described. The aqueous surface treatment agent for PVC leather of the present invention (hereinafter, simply referred to as "aqueous surface treatment agent") is an aqueous surface treatment agent for treating the surface of a leather substrate having a surface containing PVC, The aqueous surface treatment agent is (D) a chain extension product of an isocyanate-terminated prepolymer, which is a reaction product of (A) an organic polyisocyanate, (B) a polyol, and (C) a polyhydric alcohol, with a polyamine having two or more amino groups and / or imino groups; or (A) an organic polyisocyanate; (B) a polyol; (E) a compound having an anionic hydrophilic group and at least two active hydrogen atoms; and (C) a polyhydric alcohol. The neutralized prepolymer isocyanate-terminated, and the prepolymer is chain-extended by (D) a polyamine having two or more amino groups and / or imino groups. Including, The (B) polyol contains (B1) a polycarbonate diol composed only of a diol having a linear structure and an even number of carbon atoms of 4 to 10, The (C) polyhydric alcohol includes a polyhydric alcohol having at least three active hydrogens.

[0017] Here, when the isocyanate-terminated prepolymer is a reaction product of (A) an organic polyisocyanate, (B) a polyol, and (C) a polyhydric alcohol, the isocyanate-terminated prepolymer is a forced-emulsification type isocyanate-terminated prepolymer, and the aqueous surface treatment agent containing the chain extension product of this forced-emulsification type isocyanate-terminated prepolymer is a forced-emulsification type aqueous surface treatment agent. Also, when the isocyanate-terminated prepolymer is a reaction product of (A) an organic polyisocyanate, (B) a polyol, (E) a compound having an anionic hydrophilic group and at least two active hydrogens, and (C) a polyhydric alcohol, the isocyanate-terminated prepolymer is a self-emulsification type isocyanate-terminated prepolymer, and the aqueous surface treatment agent containing the chain extension product of the neutralization product of this self-emulsification type isocyanate-terminated prepolymer is a self-emulsification type aqueous surface treatment agent.

[0018] As described above, the aqueous surface treatment agent of the present invention may be either the forced emulsification type or the self-emulsification type aqueous surface treatment agent. However, from the viewpoint that the obtained PVC leather does not generate any unevenness due to the emulsifier, the self-emulsification type aqueous surface treatment agent is preferable.

[0019] The forcibly emulsified isocyanate-terminated prepolymer and aqueous surface treatment agent do not have an anionic hydrophilic group (a carboxy group, a carboxylate group, a sulfo group, a sulfonate group, etc.), do not exhibit self-emulsifying properties, and require the addition of an emulsifier to emulsify in water. The forcibly emulsified isocyanate-terminated prepolymer and aqueous surface treatment agent are of a type that can be forcibly emulsified by the emulsifier (forcibly emulsified type).

[0020] The self-emulsifying isocyanate-terminated prepolymer and aqueous surface treatment agent have an anionic hydrophilic group (a carboxy group, a carboxylate group, a sulfo group, a sulfonate group, etc.) and are of a type (self-emulsifying type) that can self-emulsify without using an emulsifier.

[0021] The term "aqueous" in the forcibly emulsified aqueous surface treatment agent means that after the chain extended product of the forcibly emulsified isocyanate-terminated prepolymer is emulsified and dispersed in water using an emulsifier to prepare an emulsion dispersion in which the concentration of the chain extended product of the forcibly emulsified isocyanate-terminated prepolymer in water is 35% by mass, the emulsion dispersion can be allowed to stand at 20°C for 12 hours without separation or precipitation being observed.

[0022] Furthermore, the term "aqueous" in the self-emulsifying aqueous surface treatment agent means that after emulsifying and dispersing the chain extended product of the neutralization product of the self-emulsifying isocyanate-terminated prepolymer in water to prepare an emulsion dispersion in which the concentration of the chain extended product of the neutralization product of the self-emulsifying isocyanate-terminated prepolymer in water is 35 mass%, the emulsion dispersion can be allowed to stand at 20°C for 12 hours in such a state that no separation or precipitation is observed.

[0023] The components contained in the forced emulsification type and self-emulsification type isocyanate-terminated prepolymer and the aqueous surface treatment agent will be described below.

[0024] (A) Organic polyisocyanate (hereinafter referred to as "Component A") The component A used in the present invention is not particularly limited, and examples thereof include aromatic, aliphatic and alicyclic polyisocyanates that have been generally used in the past. For example, examples of aromatic polyisocyanates include m-phenylene diisocyanate, p-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 3,3'-dichloro-4,4'-biphenylene diisocyanate, 1,5-naphthalene diisocyanate, tolidine diisocyanate, tetramethylene xylylene diisocyanate, xylylene diisocyanate, etc. Examples of the aliphatic polyisocyanate include tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, and lysine diisocyanate. Examples of the alicyclic polyisocyanate include isophorone diisocyanate, hydrogenated xylylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 3,3'-dimethyl-4,4'-dicyclohexylmethane diisocyanate, norbornane diisocyanate, and 1,3-bis(isocyanatomethyl)cyclohexane. These A components may be used alone or in combination of two or more. Among these components A, aliphatic polyisocyanates and alicyclic polyisocyanates are preferred from the viewpoint of non-yellowing of the resulting aqueous surface treatment agent, and aliphatic polyisocyanates are more preferred from the viewpoint of crumpling resistance and alcohol resistance.

[0025] (B) Polyol (hereinafter referred to as "Component B") The component B used in the present invention contains (B1) a polycarbonate diol composed only of a diol having a linear structure and an even number of carbon atoms of 4 to 10.

[0026] The weight average molecular weight of the polycarbonate diol (B1) is preferably 500 to 3000, and more preferably 800 to 2500. If the weight average molecular weight of the polycarbonate diol (B1) is less than the lower limit, the crumpling resistance may decrease, whereas if it exceeds the upper limit, the viscosity of the polycarbonate diol (B1) itself tends to be too high, which may make handling difficult.

[0027] Examples of the diol having a straight-chain structure (straight-chain hydrocarbon group) with an even carbon number of 4 to 10 include 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, and 1,10-decanediol.

[0028] Specific examples of the (B1) polycarbonate diol include polycarbonate diols derived from 1,4-butanediol / 1,6-hexanediol (e.g., Duranol T4692 (weight average molecular weight: 2000) manufactured by Asahi Kasei Corporation), polycarbonate diols derived from 1,4-butanediol / 1,10-decanediol (e.g., Benebiol NL2010DB (weight average molecular weight: 2000) manufactured by Mitsubishi Chemical Corporation), and polycarbonate diols derived only from 1,6-hexanediol (e.g., Benebiol NL2010DB (weight average molecular weight: 2000) manufactured by Mitsubishi Chemical Corporation). Examples of the polycarbonate diol include, for example, Duranol T6002 (weight average molecular weight: 2000) manufactured by Asahi Kasei Corporation, ETERNACOLLUH-200 (weight average molecular weight: 2000) manufactured by Ube Industries, Ltd., and Duranol T6001 (weight average molecular weight: 1000) manufactured by Asahi Kasei Corporation, and polycarbonate diol derived only from 1,10-decanediol (for example, Benebiol NL2000D (weight average molecular weight: 2000) manufactured by Mitsubishi Chemical Corporation).

[0029] The (B1) polycarbonate diol may be used alone or in combination of two or more kinds.

[0030] Examples of the polyol other than the polycarbonate diol (B1) in the component B (hereinafter also referred to as "other polyol") include high molecular weight polyols such as polyether polyols, polyester polyols, and polycarbonate polyols other than the polycarbonate diol (B1) (hereinafter also referred to as "other polycarbonate polyols"), and low molecular weight diols.

[0031] Examples of polyether polyols include polymers of alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide. Such polymers may be homopolymers of one type of alkylene oxide, or copolymers of two or more types of alkylene oxide. In the case of copolymers, they may be random polymers or block polymers. The weight average molecular weight of such polyether polyols is preferably 400 to 5000. In addition, as the polyether polyols, compounds in which one or more types of alkylene oxides are added to a low molecular weight dihydric alcohol may also be used. Examples of the low molecular weight dihydric alcohols include ethylene glycol, propylene glycol, and 1,4-butanediol.

[0032] Examples of polyester polyols include diol components such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycols having a weight average molecular weight of 300 to 1,000, dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexanedimethanol, bisphenol A, bisphenol S, hydrogenated bisphenol A, hydroquinone, or alkylene oxide adducts thereof, and diol components such as diphenyl ether, tert-butyl ... Examples of the polyester polyol include polyester polyols obtained by a dehydration condensation reaction with a dicarboxylic acid component such as maleic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic anhydride, fumaric acid, 1,3-cyclopentanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, 1,2-bisphenoxyethane-p,p'-dicarboxylic acid, anhydrides or ester-forming derivatives of dicarboxylic acids; polyester polyols obtained by a ring-opening polymerization reaction of a cyclic ester compound such as ε-caprolactone; and polyester polyols copolymerized with these.

[0033] Examples of the other polycarbonate-based polyols include polycarbonate-based polyols obtained by reacting a diol other than a diol having a linear structure (straight-chain hydrocarbon group) with an even carbon number of 4 to 10 (hereinafter also referred to as "other diol") with diphenyl carbonate, phosgene, etc., and polycarbonate-based polyols obtained by reacting a mixture of a diol having a linear structure (straight-chain hydrocarbon group) with an even carbon number of 4 to 10 and the other diol with diphenyl carbonate, phosgene, etc. Examples of the other diols include diols having a straight-chain structure (straight-chain hydrocarbon group) with an odd number of carbon atoms, such as 1,3-propanediol, 1,5-pentanediol, 1,7-heptanediol, and 1,9-nonanediol; diols having a branched structure (branched hydrocarbon group), such as 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol, and 2-butyl-2-ethyl-1,3-propanediol; and diols having an ethylene chain, such as ethylene glycol and diethylene glycol. Specific examples of the other polycarbonate polyols include polycarbonate diol derived only from 1,3-propanediol (HS PD-2003 manufactured by Toyokuni Oil Mills Co., Ltd.), polycarbonate diol derived only from 2-methyl-1,3-propanediol (ETERNACOLL UP-200 manufactured by Ube Industries, Ltd.), polycarbonate diol derived from 1,5-pentanediol and 1,6-hexanediol (DURANOL T5652 manufactured by Asahi Kasei Corporation), and polycarbonate diol derived from 3-methyl-1,5-pentanediol and 1,6-hexanediol (Kuraray Polyol C-2090 manufactured by Kuraray Co., Ltd.).

[0034] Examples of the low molecular weight diol include ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, 1,6-hexanediol, nonanediol, and neopentyl glycol.

[0035] These other polyols may be used alone or in combination of two or more.

[0036] The proportion of the (B1) polycarbonate diol in the B component is preferably 40% by mass or more based on the total amount of the (B) polyol from the viewpoints of abrasion resistance, chafing resistance, plasticizer migration resistance, and alcohol resistance. In particular, when the (B1) polycarbonate diol is used in combination with the other polycarbonate polyol, the proportion is more preferably 50% by mass or more from the viewpoint of further improving alcohol resistance, and even more preferably 60% by mass or more from the viewpoint of further improving abrasion resistance and chafing resistance. It is even more preferable that the content is 0% by mass or more, and particularly preferable that the content is 90% by mass or more. When the (B1) polycarbonate diol is used in combination with the other polyols (excluding the other polycarbonate polyols), from the viewpoint of further improving the abrasion resistance, chafing resistance, plasticizer migration resistance, and alcohol resistance, it is more preferable that the content is 60% by mass or more, and from the viewpoint of further improving the abrasion resistance, plasticizer migration resistance, and alcohol resistance, it is more preferable that the content is 70% by mass or more, and even more preferable that the content is 90% by mass or more.

[0037] (C) Polyhydric alcohol (hereinafter referred to as "Component C") The C component used in the present invention contains a polyhydric alcohol having at least three or more active hydrogens. Examples of such C components include trimethylolpropane, pentaerythritol, sorbitol, and other low molecular weight polyhydric alcohols having a valence of three or more. In addition, compounds having a weight average molecular weight of 500 or less obtained by adding one or more alkylene oxides to such low molecular weight polyhydric alcohols having a valence of three or more or low molecular weight polyalkylene polyamines can also be used. Examples of the low molecular weight polyalkylene polyamines include diethylenetriamine and triethylenetetramine. Examples of the alkylene oxides include ethylene oxide, propylene oxide, butylene oxide, and the like. Among such C components, trihydric to tetrahydric polyhydric alcohols are preferred from the viewpoint of wear resistance, and trihydric polyhydric alcohols are more preferred.

[0038] (D) Polyamine having two or more amino groups and / or imino groups (hereinafter referred to as "Component D") Examples of the component D used in the present invention include diamines such as ethylenediamine, propylenediamine, tetramethylenediamine, hexamethylenediamine, diaminocyclohexylmethane, hydrazine, 2-methylpiperazine, isophoronediamine, norboranediamine, diaminodiphenylmethane, tolylenediamine, and xylylenediamine; polyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and iminobispropylamine; diprimary amines and monoamines. Examples of the polyamines include amidoamines derived from polycarboxylic acids; water-soluble amine derivatives such as monoketimines of diprimary amines; and hydrazine derivatives such as oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, itaconic acid dihydrazide, 1,1'-ethylene hydrazine, 1,1'-trimethylene hydrazine, and 1,1'-(1,4-butylene) dihydrazine. These polyamines may be used alone or in combination of two or more. In addition, the amount of such D component used is preferably an amount containing 0.7 to 1.2 equivalents of amino groups relative to the free isocyanate groups of the forced emulsification type isocyanate group-terminated prepolymer and the self-emulsification type isocyanate group-terminated prepolymer described below from the viewpoint of abrasion resistance.

[0039] (E) A compound having an anionic hydrophilic group and at least two active hydrogens (hereinafter referred to as "Component E") Component E is a compound having an anionic hydrophilic group such as a carboxy group, a carboxylate group, a sulfo group, or a sulfonate group, and two or more active hydrogen-containing groups such as a hydroxy group. By copolymerizing this component E, a self-emulsifying isocyanate-terminated prepolymer and an aqueous surface treatment agent can be obtained. Examples of component E include 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolvaleric acid, dihydroxymaleic acid, and 2,6-dihydroxybenzoic acid.

[0040] The content of the anionic hydrophilic group derived from component E relative to the chain extension product of the neutralized product of the self-emulsifying isocyanate group-terminated prepolymer is preferably 0.3 to 3.0% by mass, more preferably 0.5 to 3.0% by mass, and even more preferably 0.5 to 2.5% by mass. If the content of the anionic hydrophilic group derived from component E is less than the lower limit, the emulsion stability and storage stability of the aqueous surface treatment agent tend to decrease, while if it exceeds the upper limit, the surface treatment layer treated with the aqueous surface treatment agent tends to become too hard, and there is a risk of the crumpling resistance decreasing.

[0041] (Forced emulsification type water-based surface treatment agent) The forced emulsification type aqueous surface treatment agent of the present invention contains a chain extension product of a forced emulsification type isocyanate group-terminated prepolymer which is a reaction product of the A component, the B component and the C component.

[0042] (Forced emulsification type isocyanate-terminated prepolymer) The forcibly emulsified isocyanate-terminated prepolymer is a reaction product of components A, B and C. There is no particular limitation on the method for producing such a forcibly emulsified isocyanate-terminated prepolymer, and examples thereof include the conventionally known one-stage so-called one-shot method and the multi-stage isocyanate polyaddition reaction method. The reaction temperature is preferably 40 to 150°C. In this case, if necessary, a reaction catalyst such as dibutyltin dilaurate, stannous octoate, dibutyltin di-2-ethylhexoate, triethylamine, triethylenediamine, N-methylmorpholine, bismuth tris(2-ethylhexanoate), or a reaction inhibitor such as phosphoric acid, sodium hydrogen phosphate, paratoluenesulfonic acid, adipic acid, or benzoyl chloride may be added.

[0043] In addition, an organic solvent that does not react with isocyanate groups may be added during or after the reaction. Examples of such organic solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, dioxane, dimethylformamide, dimethyl sulfoxide, toluene, xylene, ethyl acetate, butyl acetate, and methylene chloride. Among these organic solvents, methyl ethyl ketone, toluene, and ethyl acetate are particularly preferred. In addition, these organic solvents can be removed by heating and reducing pressure after the forced emulsion type isocyanate group-terminated prepolymer is emulsified and dispersed and chain extended.

[0044] In the forcibly emulsified isocyanate group-terminated prepolymer, the ratio of the C component to the total amount of the B component and the C component [(C / (B+C))×100] is preferably 0.1 to 1.5% by mass, more preferably 0.15 to 1.45% by mass, even more preferably 0.2 to 1.4% by mass, particularly preferably 0.25 to 1.35% by mass, and most preferably 0.3 to 0.95% by mass. If the ratio of the C component to the total amount of the B component and the C component is less than the lower limit, the crosslink density of the aqueous surface treatment agent tends to be low, and the abrasion resistance, plasticizer migration resistance, and alcohol resistance may be insufficient. On the other hand, if it exceeds the upper limit, the crosslink density of the aqueous surface treatment agent tends to be too high, and the crumpling resistance may be reduced.

[0045] In producing the forcibly emulsified isocyanate-terminated prepolymer, the molar ratio (NCO / OH) of the isocyanate group to the hydroxyl group of the raw material is preferably 2.0 / 1.0 to 1.1 / 1.0, more preferably 1.7 / 1.0 to 1.15 / 1.0. By adjusting the molar ratio of the isocyanate group to the hydroxyl group of the raw material within the above range, a forcibly emulsified isocyanate-terminated prepolymer having a desired free isocyanate group content can be obtained. On the other hand, if the molar ratio of the isocyanate group to the hydroxyl group of the raw material is less than the lower limit, the abrasion resistance may decrease. On the other hand, if it exceeds the upper limit, the viscosity during production may become too high, making production difficult and reducing the crumpling resistance.

[0046] The content of free isocyanate groups in the forcibly emulsified isocyanate-terminated prepolymer thus obtained is preferably 0.2 to 4.0% by mass, more preferably 0.6 to 3.5% by mass, and even more preferably 0.8 to 2.5% by mass. If the free isocyanate group content is less than the lower limit, the viscosity of the forcibly emulsified isocyanate-terminated prepolymer during production tends to increase significantly, making emulsion dispersion difficult or requiring a large amount of organic solvent, which tends to be cost-inefficient. On the other hand, if the free isocyanate group content exceeds the upper limit, the balance of water solubility after emulsion dispersion and after chain extension by component D tends to change significantly, and the storage stability or processing stability of the aqueous surface treatment agent over time may decrease, and the crumpling resistance may decrease.

[0047] In addition, each of the components A, B, and C has a plurality of reaction sites. The forcibly emulsified isocyanate-terminated prepolymer obtained by reacting such components A, B, and C has a complex structure, and it is impossible to directly represent it by a general formula (structural formula).

[0048] (Chain extension product of forced emulsification type isocyanate-terminated prepolymer) The chain-extended product of the forcibly emulsified isocyanate-terminated prepolymer is obtained by emulsifying and dispersing the forcibly emulsified isocyanate-terminated prepolymer in water using an emulsifier, and then chain-extending the prepolymer using component D.

[0049] (emulsification dispersion) As a method for emulsifying and dispersing the forcibly emulsified isocyanate-terminated prepolymer, there can be mentioned a method in which the forcibly emulsified isocyanate-terminated prepolymer is used and emulsified and dispersed in water using an emulsifier.

[0050] The emulsifier includes nonionic surfactants and anionic surfactants. Examples of the nonionic surfactants include polyoxyethylene distyryl phenyl ether type nonionic surfactants, polyoxyethylene propylene distyryl phenyl ether type nonionic surfactants, polyoxyethylene tristyryl phenyl ether type nonionic surfactants, polyoxyethylene propylene tristyryl phenyl ether type nonionic surfactants, and Pluronic (registered trademark) type nonionic surfactants. Examples of the anionic surfactants include higher alcohol sulfate salts, higher alkyl ether sulfate salts, polyalkylene glycol sulfate salts, polyoxyalkylene aryl ether sulfate salts, polyoxyalkylene aryl ether phosphate salts, sulfated fatty acid esters, alkylbenzene sulfonates, alkylnaphthalene sulfonates, naphthalene sulfonates and their polymers, paraffin sulfonates, dialkyl sulfosuccinates, polystyrene sulfonates, lignin sulfonates, and alkyl ether phosphate salts. Although such emulsifiers may be used alone or in combination of two or more, it is preferable to use at least one of the above nonionic surfactants, and from the viewpoint of storage stability and processing stability of the aqueous emulsion dispersion of the forced emulsification type aqueous surface treatment agent, it is more preferable to use one having an HLB value of 7 to 16. In the present invention, the HLB value is a value obtained by the following formula: molecular weight of the oxyethylene group portion in the nonionic surfactant × 20 / molecular weight of the nonionic surfactant.

[0051] The amount of the emulsifier to be added varies depending on the hydrophilicity of the forcibly emulsified isocyanate-terminated prepolymer, and cannot be generally stated, but is preferably 0.5 to 10 parts by mass, more preferably 1 to 6 parts by mass, relative to 100 parts by mass of the forcibly emulsified isocyanate-terminated prepolymer. If the amount of the emulsifier to be added is less than the lower limit, it tends to be difficult to obtain a sufficiently stable emulsion dispersion state, while if it exceeds the upper limit, the water resistance of the surface treatment layer obtained by coating the aqueous surface treatment agent tends to decrease, or the PVC leather tends to become rough.

[0052] (Chain extension) Next, the forcibly emulsified isocyanate-terminated prepolymer thus emulsified and dispersed in water is chain-extended using component D to form the forcibly emulsified aqueous surface treatment agent of the present invention.

[0053] The method of chain extension is not particularly limited, and for example, a method of chain extension by adding component D to an emulsified dispersion of the forcibly emulsified isocyanate group-terminated prepolymer is preferred, or a method of chain extension by adding an emulsified dispersion of the forcibly emulsified isocyanate group-terminated prepolymer to component D. The reaction between the forcibly emulsified isocyanate group-terminated prepolymer and component D is completed at a reaction temperature of 20 to 50° C., and usually within 30 to 120 minutes after mixing the forcibly emulsified isocyanate group-terminated prepolymer and component D.

[0054] Such chain extension may be carried out simultaneously with the emulsification dispersion, after the emulsification dispersion, or before the emulsification dispersion. In addition, when an organic solvent is contained in the obtained forced emulsification type aqueous surface treatment agent, it is preferable to remove the organic solvent at a temperature of 30 to 80° C. under reduced pressure.

[0055] Like components A, B, and C, component D also has a plurality of reaction sites, and the chain-extended product of the forcibly emulsified isocyanate-terminated prepolymer (forcibly emulsified aqueous surface treatment agent) obtained by chain-extending the forcibly emulsified isocyanate-terminated prepolymer using component D also has a complex structure, like the forcibly emulsified isocyanate-terminated prepolymer, and cannot be directly represented by a general formula (structural formula).

[0056] The thus obtained forced emulsification type aqueous surface treatment agent is preferably used in a state of being emulsified and dispersed in water, and the concentration of the chain extension product of the forced emulsification type isocyanate group-terminated prepolymer in the aqueous surface treatment agent is not particularly limited, but is preferably 20 to 60 mass %. The concentration of the chain extension product of the forced emulsification type isocyanate group-terminated prepolymer in such an aqueous emulsion dispersion of the forced emulsification type aqueous surface treatment agent (hereinafter also referred to as "aqueous dispersion of the chain extension product of the forced emulsification type isocyanate group-terminated prepolymer") can be adjusted by adding or removing water.

[0057] (Self-emulsifying water-based surface treatment agent) The self-emulsifying aqueous surface treatment agent of the present invention contains a chain-extended product of a neutralized self-emulsifying isocyanate-terminated prepolymer, which is a reaction product of the A component, the B component, the C component and the E component.

[0058] (Self-emulsifying isocyanate-terminated prepolymer) The self-emulsifying isocyanate-terminated prepolymer is a reaction product of components A, B, C, and E. As a method for producing such a self-emulsifying isocyanate-terminated prepolymer, a method similar to the method for producing the forcedly emulsified isocyanate-terminated prepolymer can be adopted, except that component E is included.

[0059] In the self-emulsifying isocyanate group-terminated prepolymer, the ratio of the C component to the total amount of the B component, the C component, and the E component [(C / (B+C+E))×100] is preferably 0.1 to 1.5% by mass, more preferably 0.15 to 1.45% by mass, even more preferably 0.2 to 1.4% by mass, particularly preferably 0.25 to 1.35% by mass, and most preferably 0.3 to 0.95% by mass. If the ratio of the C component to the total amount of the B component, the C component, and the E component is less than the lower limit, the crosslink density of the aqueous surface treatment agent tends to be low, and the abrasion resistance, plasticizer migration resistance, and alcohol resistance may be insufficient. On the other hand, if it exceeds the upper limit, the crosslink density of the aqueous surface treatment agent tends to be too high, and the crumpling resistance may be reduced.

[0060] In producing the self-emulsifying isocyanate-terminated prepolymer, the molar ratio (NCO / OH) of the isocyanate group to the hydroxyl group of the raw material is preferably 2.0 / 1.0 to 1.1 / 1.0, more preferably 1.7 / 1.0 to 1.15 / 1.0. By adjusting the molar ratio of the isocyanate group to the hydroxyl group of the raw material within the above range, a self-emulsifying isocyanate-terminated prepolymer having a desired free isocyanate group content can be obtained. On the other hand, if the molar ratio of the isocyanate group to the hydroxyl group of the raw material is less than the lower limit, the abrasion resistance may decrease. On the other hand, if it exceeds the upper limit, the viscosity during production may become too high, making production difficult and reducing the crumpling resistance.

[0061] The content of free isocyanate groups in the thus obtained self-emulsifying isocyanate-terminated prepolymer is preferably 0.2 to 4.0% by mass, more preferably 0.6 to 3.5% by mass, and even more preferably 0.8 to 2.5% by mass. If the free isocyanate group content is less than the lower limit, the viscosity of the self-emulsifying isocyanate-terminated prepolymer during production tends to increase significantly, making emulsion dispersion difficult or requiring a large amount of organic solvent, which tends to be cost-inefficient. On the other hand, if the free isocyanate group content exceeds the upper limit, the balance of water solubility after emulsion dispersion and after chain extension by component D tends to change significantly, and the storage stability or processing stability of the aqueous surface treatment agent over time may decrease, and the crumpling resistance may decrease.

[0062] In addition, each of the components A, B, C, and E has a plurality of reaction sites. The self-emulsifying isocyanate-terminated prepolymer obtained by reacting such components A, B, C, and E has a complex structure, and it is impossible to directly represent it by a general formula (structural formula).

[0063] (Neutralized self-emulsifying isocyanate-terminated prepolymer) The neutralized product of the self-emulsifying isocyanate-terminated prepolymer is a product in which the anionic hydrophilic group in the self-emulsifying isocyanate-terminated prepolymer is neutralized. Such a neutralized product of the self-emulsifying isocyanate-terminated prepolymer may be produced by (i) neutralizing the anionic hydrophilic group in the self-emulsifying isocyanate-terminated prepolymer obtained by reacting the A component, the B component, the C component, and the E component by a known method, or (ii) mixing the A component, the B component, the C component, and the E component, neutralizing the anionic hydrophilic group in the E component by a known method, and then reacting the neutralized E component, the A component, the B component, and the C component. The neutralized product of the self-emulsifying isocyanate-terminated prepolymer may also be produced by (iii) reacting the A component, the B component, the C component, and the E component in which the anionic hydrophilic group is a salt of the anionic hydrophilic group.

[0064] In the manufacturing methods (i) and (ii) above, the basic compound used for neutralizing the anionic hydrophilic group of component E is not particularly limited, and examples thereof include amines such as trimethylamine, triethylamine, tri-n-propylamine, tributylamine, N-methyl-diethanolamine, N,N-dimethylmonoethanolamine, N,N-diethylmonoethanolamine, triethanolamine, etc.; alkali metal hydroxides such as potassium hydroxide, sodium hydroxide, etc.; ammonia, etc. Among these, tertiary amines such as trimethylamine, triethylamine, tri-n-propylamine, tributylamine, etc. are particularly preferred.

[0065] In the neutralization of the anionic hydrophilic group of the E component in the manufacturing methods (i) and (ii), the amount of the neutralizing basic compound is preferably 0.5 to 1.5 equivalents, more preferably 0.6 to 1.4 equivalents, and particularly preferably 0.7 to 1.3 equivalents relative to the anionic hydrophilic group. If the amount of the neutralizing basic compound is less than the lower limit, the emulsification and storage stability of the neutralized product of the self-emulsifying isocyanate-terminated prepolymer tend to decrease. On the other hand, even if the amount of the neutralizing basic compound is added in an amount exceeding the upper limit, the emulsification and storage stability of the neutralized product of the self-emulsifying isocyanate-terminated prepolymer do not improve any more, which is economically undesirable.

[0066] (Chain extension product of neutralized self-emulsifying isocyanate-terminated prepolymer) The chain-extended product of the neutralized product of the self-emulsifying isocyanate-terminated prepolymer is obtained by emulsifying the neutralized product of the self-emulsifying isocyanate-terminated prepolymer in water and then chain-extending the neutralized product using component D.

[0067] (emulsification dispersion) The neutralized product of the self-emulsifying isocyanate-terminated prepolymer can be emulsified and dispersed in water without using an emulsifier. The method for emulsifying and dispersing the neutralized product of the self-emulsifying isocyanate-terminated prepolymer is not particularly limited, and examples thereof include conventionally known methods using a homomixer, a homogenizer, a disperser, etc. The neutralized product of the self-emulsifying isocyanate-terminated prepolymer can be emulsified and dispersed in water at a temperature in the range of 0 to 40°C without adding an emulsifier. This makes it possible to suppress the reaction between the isocyanate group and water. In addition, when emulsifying and dispersing the neutralized product of the self-emulsifying isocyanate-terminated prepolymer, a reaction inhibitor such as phosphoric acid, sodium dihydrogen phosphate, disodium hydrogen phosphate, paratoluenesulfonic acid, adipic acid, or benzoyl chloride may be added as necessary.

[0068] (Chain extension) Next, the neutralized product of the self-emulsifying isocyanate group-terminated prepolymer emulsified and dispersed in water in this way is chain-extended using Component D, whereby the self-emulsifying aqueous surface treatment agent of the present invention is formed.

[0069] The method of chain extension is not particularly limited, and the same method as the method of chain extension of the forced emulsification type isocyanate group-terminated prepolymer can be adopted.

[0070] Note that, similar to Components A, B, C, and E, Component D also has a plurality of reaction points, and the chain extension product (self-emulsifying aqueous surface treatment agent) of the neutralized product of the self-emulsifying isocyanate group-terminated prepolymer obtained by chain-extending the neutralized product of the self-emulsifying isocyanate group-terminated prepolymer using such Component D is also complex in structure and cannot be directly represented by a general formula (structural formula), similar to the self-emulsifying isocyanate group-terminated prepolymer.

[0071] The self-emulsifying aqueous surface treatment agent thus obtained is preferably used in a state of being emulsified and dispersed in water. The concentration of the chain extension product of the neutralized product of the self-emulsifying isocyanate group-terminated prepolymer in the aqueous surface treatment agent is not particularly limited, but 20 to 60% by mass is preferred. The concentration of the chain extension product of the neutralized product of the self-emulsifying isocyanate group-terminated prepolymer in the water emulsion dispersion of such a self-emulsifying aqueous surface treatment agent (hereinafter, also referred to as "water dispersion of the chain extension product of the neutralized product of the self-emulsifying isocyanate group-terminated prepolymer") can be adjusted by adding or removing water.

[0072] <Aqueous surface treatment agent for PVC leather> The aqueous surface treatment agent for PVC leather of the present invention is an aqueous surface treatment agent for treating the surface of a leather substrate having a surface containing PVC, and by treating the PVC-containing surface with this aqueous surface treatment agent, a surface treatment layer is formed on the PVC-containing surface by the aqueous surface treatment agent, so that color, gloss, texture, touch, etc. are adjusted, and further, migration of a plasticizer contained in the PVC-containing substrate surface (for example, a PVC-containing skin layer) is suppressed, and abrasion resistance, crumple resistance, and alcohol resistance are improved. As such an aqueous surface treatment agent of the present invention, either the forced emulsification type or the self-emulsification type can be used, but a self-emulsification type aqueous surface treatment agent is preferred from the viewpoint that the resulting PVC leather does not develop sharpness due to the emulsifier.

[0073] Furthermore, in the aqueous surface treatment agent of the present invention, various additives such as resins other than the chain extended product of the forcibly emulsified isocyanate group-terminated prepolymer or the chain extended product of the neutralized product of the self-emulsified isocyanate group-terminated prepolymer, matting agents, smoothing agents, thickening agents, crosslinking agents, surfactants, defoamers, leveling agents, viscoelasticity modifiers, wetting agents, dispersants, preservatives, film-forming agents, plasticizers, penetrating agents, fragrances, bactericides, miticides, mildewproofing agents, ultraviolet absorbers, antioxidants, antistatic agents, flame retardants, dyes, and pigments may be blended within the range that does not impair the effects of the present invention.

[0074] (resin) Examples of the resin other than the chain-extended product of the forcibly emulsified isocyanate-terminated prepolymer or the chain-extended product of the neutralized product of the self-emulsified isocyanate-terminated prepolymer include acrylic resins and polyester resins.

[0075] Examples of the acrylic monomers used in the acrylic resin include (meth)acrylic acid derivatives such as methyl (meth)acrylate, ethyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, benzyl (meth)acrylate, (meth)acrylic acid, glycidyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, and 2-hydroxypropyl (meth)acrylate. Here, (meth)acrylic acid refers to acrylic acid or methacrylic acid. These acrylic monomers may be used alone or in combination of two or more.

[0076] Examples of copolymerization monomers used in the acrylic resin include aromatic vinyl compounds such as styrene, α-methylstyrene, and p-methylstyrene; acrylamides such as acrylamide, diacetone acrylamide, methacrylamide, and maleic acid amide; heterocyclic vinyl compounds such as vinyl pyrrolidone; vinyl compounds such as vinyl chloride, acrylonitrile, vinyl ether, vinyl ketone, and vinylamide; α-olefins such as ethylene and propylene; maleic acid, fumaric acid, itaconic acid, and derivatives thereof. These copolymerization monomers may be used alone or in combination of two or more.

[0077] (Matte agent) In the aqueous surface treatment agent of the present invention, a matting agent may be blended in order to adjust the luster and gloss of the PVC leather surface. Examples of such matting agents include organic beads; silica particles, talc, aluminum hydroxide, calcium sulfate, calcium silicate, calcium carbonate, magnesium carbonate, barium carbonate, alumina silicate, kaolin, mica, and other inorganic particles. These matting agents may be used alone or in combination of two or more.

[0078] Examples of the organic beads include urethane beads, acrylic beads, silicone beads, olefin beads, high density polyethylene, and low density polyethylene. Examples of the silica particles include dry silica and wet silica, and among them, dry silica is preferred from the viewpoint of high scattering effect and ability to adjust gloss value with a small amount. The average particle size of the organic beads is preferably 2 to 14 μm, more preferably 3 to 12 μm.

[0079] The amount of such a matting agent to be blended may be an appropriate amount as required from the viewpoint of improving the appearance (luster and gloss) of the target PVC leather surface, and usually, the amount is preferably 1 to 150 parts by mass, more preferably 5 to 120 parts by mass, and even more preferably 7 to 100 parts by mass, relative to 100 parts by mass of the chain-extended product of the forced-emulsification type isocyanate group-terminated prepolymer or the chain-extended product of the neutralized product of the self-emulsification type isocyanate group-terminated prepolymer.

[0080] (Smoothing agent) In the aqueous surface treatment agent of the present invention, a smoothing agent may be added to improve the smoothness and abrasion resistance of the PVC leather surface. Examples of such smoothing agents include polydimethyl silicone, hydrogen-modified silicone, vinyl-modified silicone, epoxy-modified silicone, amino-modified silicone, carboxyl-modified silicone, halogenated modified silicone, methacryloxy-modified silicone, mercapto-modified silicone, fluorine-modified silicone, alkyl-modified silicone, phenyl-modified silicone, and polyether-modified silicone. These smoothing agents may be used alone or in combination of two or more. Among these smoothing agents, polydimethyl silicone and epoxy-modified silicone are preferred from the viewpoint of their large effect of improving abrasion resistance.

[0081] In the aqueous surface treatment agent of the present invention, commercially available products can be used as such smoothing agents. Examples of commercially available polydimethyl silicone emulsions include DOWSIL SM490EX, DOWSIL SM-8706EX, DOWSIL IE-7046T, DOWSIL FBL-3289, DOWSIL Q2-3238 (all manufactured by Dow Toray Co., Ltd.), KM-752T, KM-862T, KM-9737A, and POLON MF-33 (all manufactured by Shin-Etsu Chemical Co., Ltd.). Examples of commercially available epoxy-modified silicone emulsions include DOWSIL SM-8701 (manufactured by Dow Toray Co., Ltd.), POLON MF-18T, and X-51-1264 (all manufactured by Shin-Etsu Chemical Co., Ltd.).

[0082] The blending amount of such a smoothing agent (blending amount of non-volatile matter) may be an appropriate amount depending on the smoothness and abrasion resistance of the PVC leather surface, and usually, the blending amount is preferably 1 to 150 parts by mass, more preferably 5 to 120 parts by mass, and even more preferably 7 to 100 parts by mass, per 100 parts by mass of the chain-extended product of the forcibly emulsified isocyanate group-terminated prepolymer or the chain-extended product of the neutralized product of the self-emulsified isocyanate group-terminated prepolymer.

[0083] (Thickener) In the aqueous surface treatment agent of the present invention, a thickener may be blended to adjust the viscosity to an appropriate level. Examples of such thickeners include alkali thickening acrylic resins, association type thickeners, water-soluble organic polymers, etc. These thickeners may be used alone or in combination of two or more.

[0084] In the aqueous surface treatment agent of the present invention, commercially available products can be used as the alkali-thickening acrylic resin. Commercially available products of the alkali-thickening acrylic resin include, for example, Nikasol VT-253A (manufactured by Nippon Carbide Industries Co., Ltd.), Aron A-20P, Aron A-7150, Aron A-7070, Aron B-300, Aron B-300K, and Aron B-500 (all manufactured by Toagosei Co., Ltd.), Julimer AC-10LHP, Julimer AC-10SHP, Rheogic 835H, Junron PW-110, and Junron PW-150 (all manufactured by Toagosei Co., Ltd.). Examples of suitable alkali thickening acrylic resins include Primal ASE-60, Primal TT-615, Primal RM-5 (manufactured by Rohm and Haas Japan Co., Ltd.), SN Thickener A-818, SN Thickener A-850 (manufactured by San Nopco Ltd.), Paragum 500 (manufactured by Parachem Southern Co., Ltd.), Rheolate 430 (manufactured by Elementis Japan Co., Ltd.), and Neosticker V-420 (manufactured by Nicca Chemical Co., Ltd.). Such alkali thickening acrylic resins are usually commercially available as emulsified dispersions of the resin, and are preferably used in an emulsified and dispersed state.

[0085] In addition, in the aqueous surface treatment agent of the present invention, commercially available associative thickeners can be used. Commercially available associative thickeners include, for example, Adekanol UH-450, Adekanol UH-540, Adekanol UH-752 (all manufactured by Asahi Denka Kogyo Co., Ltd.), SN Thickener 601, SN Thickener 612, SN Thickener 621N, SN Thickener 623N, SN Thickener 660T (all manufactured by San Nopco Co., Ltd.), Rheolate 244, Rheolate 278, Rheolate 300 (all manufactured by Elementis Japan Co., Ltd.), and DK Thickener SCT-275 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).

[0086] Examples of the water-soluble organic polymer include natural water-soluble organic polymers, semi-synthetic water-soluble organic polymers, and synthetic water-soluble organic polymers. Examples of the natural water-soluble organic polymer include starches such as potato starch, sweet potato starch, wheat starch, rice starch, tapioca starch, and corn starch; resin polysaccharides such as gum arabic, gum tragacanth, gum karaya, and aoi; seaweed polysaccharides such as sodium alginate, carrageenan, agar (galactan), and funori; microbial fermentation polysaccharides such as xanthan gum, pullulan, curdlan, dextrin, and levan; proteins such as casein, gelatin, arabic, glue, and collagen; pectin, chitin, and chitosan.

[0087] Examples of the semi-synthetic water-soluble organic polymer include cellulose derivatives such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, and sodium cellulose sulfate; starch derivatives such as dextrin, soluble starch, oxidized starch, carboxymethyl starch, hydroxyethyl starch, hydroxypropyl starch, dialdehyde starch, starch phosphate, and acetyl starch; and propylene glycol alginate.

[0088] Examples of the synthetic water-soluble organic polymer include polyvinyl alcohol, polyacrylic acid, polyacrylates, polyacrylamides, polyvinylpyrrolidone, polyvinyl alkyl ethers, maleic anhydride copolymers, maleic acid copolymers, and maleate copolymers.

[0089] The blending amount of such a thickener (blending amount of non-volatile matter) may be an appropriate amount depending on the viscosity of the aqueous surface treatment agent, but usually, the blending amount is preferably 0.5 to 40 parts by mass, more preferably 1 to 30 parts by mass, and even more preferably 2 to 20 parts by mass, relative to 100 parts by mass of the chain extended product of the forcibly emulsified isocyanate group-terminated prepolymer or the chain extended product of the neutralized product of the self-emulsified isocyanate group-terminated prepolymer.

[0090] (Crosslinking agent) In the aqueous surface treatment agent of the present invention, a crosslinking agent may be blended to improve the water resistance and durability of PVC leather. Examples of such crosslinking agents include carbodiimide crosslinking agents, isocyanate crosslinking agents, epoxy crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, blocked isocyanate crosslinking agents, water-dispersible isocyanate crosslinking agents, and melamine crosslinking agents. These crosslinking agents may be used alone or in combination of two or more. These crosslinking agents may be blended in either the aqueous surface treatment agent of the present invention that contains the chain extension of the forcedly emulsified isocyanate-terminated prepolymer or the chain extension of the neutralized product of the self-emulsified isocyanate-terminated prepolymer. In the case of an aqueous surface treatment agent that contains the chain extension of the neutralized product of the self-emulsified isocyanate-terminated prepolymer having a carboxyl group, it is particularly preferable to blend a carbodiimide crosslinking agent among these crosslinking agents from the viewpoint of texture and stability of the processing liquid.

[0091] In the aqueous surface treatment agent of the present invention, commercially available products can be used as such crosslinking agents. Examples of commercially available carbodiimide crosslinking agents include Carbodilite E-02, Carbodilite SV-02, Carbodilite V02-L2, Carbodilite V-10 (all manufactured by Nisshinbo Chemical Co., Ltd.), NK Assist CI-02 (manufactured by Nicca Chemical Co., Ltd.), etc.

[0092] The blending amount of such a crosslinking agent (blending amount of non-volatile matter) is preferably 1 to 15 parts by mass, and more preferably 2 to 10 parts by mass, per 100 parts by mass of the chain-extended product of the forcibly emulsified isocyanate group-terminated prepolymer or the chain-extended product of the neutralized product of the self-emulsified isocyanate group-terminated prepolymer, from the viewpoint of the abrasion resistance and rubbing resistance of the PVC leather.

[0093] [PVC resin leather] The vinyl chloride resin leather (PVC leather) of the present invention is a leather substrate (PVC leather substrate) having a surface containing vinyl chloride resin (PVC), the PVC-containing surface of which is provided with a surface treatment layer formed from the aqueous surface treatment agent for PVC leather of the present invention.

[0094] (PVC leather base material) The leather substrate used in the present invention is not particularly limited as long as it is a PVC leather substrate having a surface containing PVC, and the entire substrate may contain PVC. Generally, however, examples include a PVC leather substrate (13) comprising a base fabric (11) and a skin layer (12) containing PVC formed on the base fabric (11) as shown in FIG. 1, and a PVC leather substrate (24) comprising a base fabric (21), an intermediate layer (22) (e.g., a foam layer, etc.) formed on the base fabric (21), and a skin layer (23) containing PVC formed on the intermediate layer (22) as shown in FIG. 2. An adhesive layer (not shown) may be formed between the base fabric (11) and the skin layer (12) in FIG. 1, between the base fabric (21) and the intermediate layer (22) in FIG. 2, and / or between the intermediate layer (22) and the skin layer (23).

[0095] (base fabric) The base fabric is not particularly limited, and includes fibers that can be used for PVC leather, and known fibers can be used appropriately. Examples of such fibers include knitted fabrics, woven fabrics, nonwoven fabrics, and similar materials. From the viewpoint of imparting leather-like properties, it is preferable to use knitted fabrics (for example, stockinette knits such as plain knit and smooth knit) as such fibers, and among them, knitted fabrics using yarns that have been given elasticity by shrink processing or the like are particularly preferable. When using knitted fabrics made only of polyester as such fibers, it is preferable to use them as knitted fabrics with increased elasticity by shrink processing, since polyester is hard. In addition, when the fibers are woven fabrics or nonwoven fabrics, it is preferable to give flexibility to the fabrics (said woven fabrics or said nonwoven fabrics) by using, for example, those that have been given elasticity by shrink processing or the like as the yarns constituting the woven fabrics and the short fibers (staples) constituting the nonwoven fabrics, or by using yarns that have been processed to give elasticity when making yarns from short fibers.

[0096] The method of producing the fibers is not particularly limited, and known methods can be appropriately adopted. Commercially available fibers may be used as such fibers. The thickness of the fibers (base fabric) used in such PVC leather varies depending on the design of the synthetic resin leather to be produced, and is not particularly limited, but is preferably about 300 to 1000 μm from the viewpoint of the strength and elasticity of the processed product.

[0097] (Vinyl chloride resin) Polyvinyl chloride resin (PVC) is a polymer containing vinyl chloride or vinylidene chloride as an essential monomer component. That is, PVC is a polymer containing at least a structural unit derived from vinyl chloride or vinylidene chloride in the molecule (per molecule). Examples of the polyvinyl chloride include polyvinyl chloride, which is a homopolymer of vinyl chloride, polyvinylidene chloride, which is a homopolymer of vinylidene chloride, copolymers of vinyl chloride or vinylidene chloride with other monomers, chlorinated polyvinyl chloride, and chlorinated polyolefin.

[0098] Examples of the copolymer of vinyl chloride or vinylidene chloride with other monomers include vinyl chloride-vinyl acetate copolymer, vinyl chloride-ethylene copolymer, vinyl chloride-propylene copolymer, vinyl chloride-styrene copolymer, vinyl chloride-isobutylene copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-urethane copolymer, vinyl chloride-butadiene copolymer, vinyl chloride-isoprene copolymer, vinyl chloride-chlorinated propylene copolymer, vinyl chloride-vinyl ester copolymer such as vinyl chloride-maleic acid ester copolymer and vinyl chloride-(meth)acrylic acid ester copolymer, vinyl chloride-styrene-maleic anhydride terpolymer, vinyl chloride-styrene-acrylonitrile terpolymer, vinyl chloride-vinylidene chloride-vinyl acetate terpolymer, ethylene-vinyl acetate-vinyl chloride copolymer, etc. Among these, the PVC is preferably a homopolymer of vinyl chloride.

[0099] The average degree of polymerization of the PVC (a value measured in accordance with JIS K6721) is not particularly limited, but is preferably 1,000 to 3,500, more preferably 1,100 to 3,000, and even more preferably 1,300 to 2,800.

[0100] The method for producing the PVC is not particularly limited, and any known method can be appropriately adopted.

[0101] (Skin layer containing PVC) The PVC-containing skin layer is a skin layer containing the PVC. Among these, a skin layer containing a homopolymer of vinyl chloride as PVC is preferred. Furthermore, the PVC-containing skin layer may contain various additives together with the PVC. In this way, the PVC-containing skin layer may be a layer formed by a composition of the PVC and the various additives. As such additives, known additives can be appropriately used, and for example, plasticizers, heat stabilizers, fillers, pigments, antistatic agents, ultraviolet absorbers, light stabilizers, and antiaging agents can be appropriately used.

[0102] Examples of the plasticizer include general phthalate ester plasticizers such as diisodecyl phthalate (DIDP), di-2-ethylhexyl phthalate (DOP), diisononyl phthalate (DINP), butyl benzyl phthalate (BBP), diundecyl phthalate (DUP), etc.; general fatty acid ester plasticizers such as dioctyl adipate (DOA), dioctyl sebacate (DOS), dioctyl azelate (DOZ); trimellitic acid ester plasticizers such as trioctyl trimellitate (TOTM), etc.; triaryl phosphate ester plasticizers such as tricresyl phosphate (TCP), trixylyl phosphate (TXP), etc.; epoxy plasticizers such as epoxidized soybean oil, etc.; polyester plasticizers such as polypropylene adipate, etc.; and general plasticizers such as chlorinated paraffin. These plasticizers may be used alone or in combination of two or more.

[0103] (Middle class) The leather substrate used in the present invention may have an intermediate layer (22) between the base fabric (21) and the PVC-containing surface layer (23), as shown in Fig. 2. An example of such an intermediate layer is a foam layer. By providing such a foam layer as an intermediate layer, cushioning properties are imparted to the PVC leather, and a PVC leather having a supple and fine texture is obtained. There is no particular limitation on the foam layer, and it may be a foam layer containing PVC, or a foam layer containing a resin other than PVC, such as a polyurethane resin (PU).

[0104] (Manufacturing method for PVC leather substrate) The method for producing the PVC leather substrate is not particularly limited, and examples thereof include, in the case of the PVC leather substrate (13) shown in FIG. 1, a method of bonding a base fabric (11) and a PVC-containing skin layer (12) together; in the case of the PVC leather substrate (24) shown in FIG. 2, a method of bonding a base fabric (21) and an intermediate layer (22) together and laminating a PVC-containing skin layer (23) thereon (on the intermediate layer (22)), and a method of laminating a PVC-containing skin layer (23) on the intermediate layer (22) and then bonding the resulting laminate to the base fabric (21).

[0105] There is no particular limitation on the method for bonding the base fabric (11) and the PVC-containing skin layer (12), the base fabric (21) and the intermediate layer (22), and the intermediate layer (22) and the PVC-containing skin layer (23), and examples of the method include a method of bonding using an adhesive, a method of bonding by heating, and a method of bonding by applying pressure, and it is sufficient to bond them using at least one method selected from the above-mentioned bonding methods. When bonding is performed using an adhesive, the method of applying the adhesive is not particularly limited, and any known method can be used as appropriate.

[0106] In the case of the PVC leather substrate (24) shown in FIG. 2, the method for bonding the base fabric (21) and the intermediate layer (22), and the intermediate layer (22) and the PVC-containing skin layer (23) may be such that one is bonded using an adhesive and the other is bonded by heating and / or pressure, or both are bonded using an adhesive, or both are bonded by heating and / or pressure.

[0107] (PVC leather) The PVC leather of the present invention comprises a leather substrate having a surface containing PVC and a surface treatment layer formed on the PVC surface by the aqueous surface treatment agent for PVC leather of the present invention. For example, as shown in Figs. 1 and 2, a PVC leather substrate (13) comprising a base fabric (11) and a skin layer (12) containing PVC, or a PVC leather substrate (24) comprising a base fabric (21), an intermediate layer (22) and a skin layer (23) containing PVC, and a surface treatment layer (14 or 25) formed on the surface of the skin layer (12 or 23) containing PVC by the aqueous surface treatment agent of the present invention. The surface treatment layer (14 or 25) and the skin layer (12 or 23) containing PVC are in direct contact with each other without any other layers in between. Such leathers are used for vehicle interior materials, motorcycle seats and grips, sports shoes, clothing, furniture, etc.

[0108] There is no particular limitation on the method for producing the PVC leather of the present invention. For example, the PVC leather of the present invention can be produced by applying the aqueous surface treatment agent of the present invention to the surface of the PVC-containing skin layer (12 or 23) of the PVC leather substrate (13 or 24), and then drying the agent to form a surface treatment layer (14 or 25) on the surface of the PVC-containing skin layer (12 or 23).

[0109] The method for applying the aqueous surface treatment agent is not particularly limited, and examples thereof include a method of applying the aqueous surface treatment agent to the surface of the PVC-containing skin layer (12 or 23) using various coaters such as a gravure coater, a bar coater, a comma coater, a blade coater, and an air knife coater; a method of spraying the aqueous surface treatment agent onto the surface of the PVC-containing skin layer (12 or 23); and a method of immersing the PVC leather substrate (13 or 24) in the aqueous surface treatment agent. Of these, a direct coating method or a reverse coating method using a gravure coater is more preferred. The amount of the aqueous surface treatment agent applied is 1 to 20 g / m after drying. 2 The amount is preferably 2 to 15 g / m 2 It is more preferable that the amount be such that

[0110] The method for drying the applied aqueous surface treatment agent is not particularly limited, and for example, drying is preferably performed for 30 seconds to 10 minutes at a temperature in the range of 40 to 160° C., and more preferably for 30 seconds to 2 minutes at a temperature in the range of 80 to 130° C. After drying, aging treatment is preferably performed for 5 to 72 hours at a temperature in the range of 20 to 100° C. EXAMPLES

[0111] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. The free isocyanate group content in the synthesis examples was measured by the following method.

[0112] (Free isocyanate group content) 0.3 g of forced emulsification type isocyanate-terminated prepolymer or self-emulsification type isocyanate-terminated prepolymer was placed in an Erlenmeyer flask, and 10 ml of 0.1 N dibutylamine toluene solution was added to dissolve the forced emulsification type isocyanate-terminated prepolymer or self-emulsification type isocyanate-terminated prepolymer. Then, several drops of bromophenol blue solution were added, and titration was performed with 0.1 N hydrochloric acid methanol solution to obtain the following formula: NCO% = (a b ) × 0.42 × f / x (In the above formula, a: the titration amount of 0.1N hydrochloric acid / methanol solution when only 10 ml of 0.1N dibutylamine toluene solution is titrated, b: the titration amount of 0.1N hydrochloric acid / methanol solution when a solution in which a forced emulsification type isocyanate-terminated prepolymer or a self-emulsification type isocyanate-terminated prepolymer is dissolved is titrated, f: the factor of the 0.1N hydrochloric acid / methanol solution, and x: the amount of forced emulsification type isocyanate-terminated prepolymer or the self-emulsification type isocyanate-terminated prepolymer). The free isocyanate group content (NCO%) was calculated by the following.

[0113] The raw materials used in the synthesis examples are shown below.

[0114] <Organic polyisocyanate> 1,5-PDI: 1,5-pentamethylene diisocyanate ("STABIO PDI" manufactured by Mitsui Chemicals, Inc.). HDI: Hexamethylene diisocyanate ("Duranate 50M" manufactured by Asahi Kasei Corporation). H12MDI: Dicyclohexylmethane 4,4'-diisocyanate ("Desmodur W" manufactured by Covestro). MDI: Diphenylmethane diisocyanate ("Millionate MT" manufactured by Tosoh Corporation).

[0115] <Polyol> NL2000D: Polycarbonate diol (1,10-decanediol) manufactured by Mitsubishi Chemical Corporation, trade name "Benebiol NL-2000D", weight average molecular weight 2,000. T4692: Polycarbonate diol (1,4-butanediol / 1,6-hexanediol) manufactured by Asahi Kasei Chemicals Corporation, trade name "Duranol T4692", weight average molecular weight 2,000. NL2010DB: Polycarbonate diol (1,4-butanediol / 1,10-decanediol) manufactured by Mitsubishi Chemical Corporation, trade name "Benebiol NL-2010DB", weight average molecular weight 2,000. T6002: Polycarbonate diol (1,6-hexanediol) manufactured by Asahi Kasei Chemicals Corporation, trade name "Duranol T6002", weight average molecular weight 2,000. T6001: Polycarbonate diol (1,6-hexanediol) manufactured by Asahi Kasei Chemicals Corporation, trade name "Duranol T6001", weight average molecular weight 1,000. C2090: Polycarbonate diol (3-methyl-1,5-pentanediol / 1,6-hexanediol) manufactured by Kuraray Co., Ltd., product name "Kuraray Polyol C-2090", weight average molecular weight 2,000. UP200: Polycarbonate diol (2-methyl-1,3-propanediol) manufactured by Ube Industries, Ltd., product name "ETERNACOLL UP-200", weight average molecular weight 2,000. HS PD2003: Polycarbonate diol (1,3-propanediol) manufactured by Toyokuni Oil Co., Ltd., product name "HS PD-2003", weight average molecular weight 2,000. PTMG2000: Polytetramethylene ether glycol manufactured by Mitsubishi Chemical Corporation, product name "PTMG2000", weight average molecular weight 2,000. 1,4-BD: 1,4-butanediol ("1,4-butanediol" manufactured by Mitsubishi Chemical Corporation).

[0116] <Trivalent or higher polyhydric alcohol> TMP: Trimethylolpropane (Perstorp's "Trimethylolpropane").

[0117] <Chain extender> N2H4: Hydrazine monohydrate ("60% hydrazine hydrate" manufactured by Nippon Carbide Industries Co., Ltd.). DETA: Diethylenetriamine ("Diethylenetriamine" manufactured by Tosoh Corporation).

[0118] <Anionic hydrophilic group / active hydrogen-containing compound> DMPA: Dimethylolpropionic acid (Perstorp "Bis-MPA").

[0119] <Neutralized amine> TEA: Triethylamine (Daicel Corporation's "Triethylamine").

[0120] The aqueous polyurethane resins used in the examples and comparative examples were synthesized by the following method.

[0121] (Synthesis Example 1) In a four-neck flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen inlet tube, 87.8 parts by mass of polycarbonate diol (1,10-decanediol) (Mitsubishi Chemical Corporation's "Benebiol NL-2000D", number average molecular weight 2,000) as (B) polyol, 0.42 parts by mass of trimethylolpropane as (C) polyhydric alcohol, and 24.8 parts by mass of methyl ethyl ketone were charged and mixed uniformly, and then 10.9 parts by mass of hexamethylene diisocyanate and 0.01 parts by mass of bismuth tris(2-ethylhexanoate) as (A) organic polyisocyanate were added and reacted at 80 ° C. for 90 minutes to obtain a methyl ethyl ketone solution of forced emulsification type isocyanate group-terminated prepolymer having a free isocyanate group content of 1.37% by mass relative to the forced emulsification type isocyanate group-terminated prepolymer.

[0122] To this solution, 0.5 parts by mass of sodium dihydrogen phosphate and 3.0 parts by mass of polyoxyethylene tristyrylphenyl ether type nonionic surfactant (HLB=13) were added and mixed uniformly, and then 180 parts by mass of water was gradually added using a dispersing blade to emulsify and disperse. 0.65 parts by mass of hydrazine monohydrate and 0.21 parts by mass of diethylenetriamine were added as chain extenders (D) to the obtained emulsion dispersion, and the mixture was stirred for 90 minutes to obtain a dispersion of chain extension product of forcibly emulsified isocyanate-terminated prepolymer. Next, the solvent was removed from this dispersion of chain extension product of forcibly emulsified isocyanate-terminated prepolymer at 40°C under reduced pressure to obtain a stable aqueous dispersion of chain extension product of forcibly emulsified isocyanate-terminated prepolymer with 35.0% by mass of chain extension product of forcibly emulsified isocyanate-terminated prepolymer, viscosity of 50 mPa·s, and average particle size of 0.3 μm.

[0123] In the obtained aqueous dispersion of the chain-extended product of the forcibly emulsified isocyanate group-terminated prepolymer, the proportion of the (B1) polycarbonate diol in the total amount of the (B) polyol, the proportion of the (C) polyhydric alcohol in the total amount of the (B) polyol and the (C) polyhydric alcohol, the content of the (D) chain extender, the free isocyanate group content in the forcibly emulsified isocyanate group-terminated prepolymer, the anionic hydrophilic group content in the chain-extended product of the forcibly emulsified isocyanate group-terminated prepolymer, and the NCO / OH ratio are shown in Table 1.

[0124] (Synthesis Example 2) Into a four-neck flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube, were added 78.97 parts by mass of polycarbonate diol (1,10-decanediol) ("Benebiol NL-2000D" manufactured by Mitsubishi Chemical Corporation, number average molecular weight 2,000) as a polyol, 0.4 parts by mass of trimethylolpropane as a polyhydric alcohol, 3.55 parts by mass of dimethylolpropionic acid as an anionic hydrophilic group / active hydrogen-containing compound, and 24.7 parts by mass of methyl ethyl ketone was charged and mixed uniformly, after which 15.8 parts by mass of hexamethylene diisocyanate as (A) organic polyisocyanate and 0.01 parts by mass of bismuth tris(2-ethylhexanoate) were added and reacted at 80°C for 90 minutes to obtain a methyl ethyl ketone solution of a self-emulsifying isocyanate-terminated prepolymer having a free isocyanate group content of 2.00 mass% relative to the self-emulsifying isocyanate-terminated prepolymer.

[0125] 2.54 parts by mass of triethylamine was added to this solution, and after uniform mixing, 185 parts by mass of water was gradually added to emulsify and disperse. 0.95 parts by mass of hydrazine monohydrate and 0.31 parts by mass of diethylenetriamine were added as chain extenders (D) to the obtained emulsion dispersion, and the mixture was stirred for 90 minutes to obtain a dispersion of a chain extension product of the neutralized product of the self-emulsifying isocyanate-terminated prepolymer. Next, the solvent was removed from the dispersion of the chain extension product of the neutralized product of the self-emulsifying isocyanate-terminated prepolymer under reduced pressure at 40°C to obtain a stable aqueous dispersion of the chain extension product of the neutralized product of the self-emulsifying isocyanate-terminated prepolymer with 35.0% by mass of the chain extension product of the neutralized product of the self-emulsifying isocyanate-terminated prepolymer, a viscosity of 100 mPa·s, and an average particle size of 0.1 μm.

[0126] In the obtained aqueous dispersion of the chain-extended product of the neutralization product of the self-emulsifying isocyanate-terminated prepolymer, the proportion of the (B1) polycarbonate diol to the total amount of the (B) polyol, the proportion of the (C) polyhydric alcohol to the total amount of the (B) polyol, the (E) anionic hydrophilic group / active hydrogen-containing compound and the (C) polyhydric alcohol, the content of the (D) chain extender, the free isocyanate group content in the self-emulsifying isocyanate-terminated prepolymer, the anionic hydrophilic group content in the chain-extended product of the neutralization product of the self-emulsifying isocyanate-terminated prepolymer and the NCO / OH ratio are shown in Table 1.

[0127] (Synthesis Examples 3 to 26 and Comparative Synthesis Examples 1 to 5) An aqueous dispersion of a chain-extended product of a neutralized product of a self-emulsifying isocyanate group-terminated prepolymer (35.0 mass% of the chain-extended product of a neutralized product of a self-emulsifying isocyanate group-terminated prepolymer) was obtained in the same manner as in Synthesis Example 2, except that the types and amounts of organic polyisocyanate, polyol, polyhydric alcohol, anionic hydrophilic group / active hydrogen-containing compound, neutralizing amine, and chain extender shown in Tables 1 to 3 were used. In the obtained aqueous dispersion of the chain-extended product of the neutralization product of the self-emulsifying isocyanate-terminated prepolymer, the proportion of the (B1) polycarbonate diol to the total amount of the (B) polyol, the proportion of the (C) polyhydric alcohol to the total amount of the (B) polyol, the (E) anionic hydrophilic group / active hydrogen-containing compound and the (C) polyhydric alcohol, the content of the (D) chain extender, the free isocyanate group content in the self-emulsifying isocyanate-terminated prepolymer, the anionic hydrophilic group content in the chain-extended product of the neutralization product of the self-emulsifying isocyanate-terminated prepolymer and the NCO / OH ratio are shown in Tables 1 to 3.

[0128] (Comparative Synthesis Examples 6-7) A water dispersion of a neutralized product of a self-emulsifying isocyanate-terminated prepolymer (35.0% by mass of a chain-extended product of a neutralized product of a self-emulsifying isocyanate-terminated prepolymer) was obtained in the same manner as in Synthesis Example 2, except that the types and amounts of organic polyisocyanate, polyol, polyhydric alcohol, anionic hydrophilic group / active hydrogen-containing compound, and neutralizing amine shown in Table 3 were used, and no chain extender (D) was used. Table 3 shows the ratio of the (B1) polycarbonate diol to the total amount of the (B) polyol, the ratio of the (C) polyhydric alcohol to the total amount of the (B) polyol, the (E) anionic hydrophilic group / active hydrogen-containing compound, and the (C) polyhydric alcohol, the free isocyanate group content in the self-emulsifying isocyanate-terminated prepolymer, the anionic hydrophilic group content in the neutralized product of the self-emulsifying isocyanate-terminated prepolymer, and the NCO / OH ratio in the obtained water dispersion of a neutralized product of a self-emulsifying isocyanate-terminated prepolymer.

[0129] Example 1 286 parts by mass of an aqueous dispersion of a chain extender of a forced emulsification type isocyanate group-terminated prepolymer obtained in Synthesis Example 1 (35.0% by mass of the chain extender of the forced emulsification type isocyanate group-terminated prepolymer), 7 parts by mass of silica particles produced by a dry method as a matting agent ("ACEMATT TS100" manufactured by Evonik Degussa, average particle diameter: 10 μm), 30 parts by mass of urethane beads ("Art Pearl P-800T" manufactured by Negami Kogyo Co., Ltd., average particle diameter: 6 μm, Tg = -34°C), 40 parts by mass of a leveling agent ("KM-862T" manufactured by Shin-Etsu Chemical Co., Ltd., non-volatile content: 60% by mass), 12 parts by mass of an associative thickener ("SN Thickener 612" manufactured by San Nopco Ltd., non-volatile content: 40% by mass), 343 parts by mass of ion-exchanged water, and 12 parts by mass of an aqueous dispersible carbodiimide-based crosslinking agent ("Carbodilite SV-02" manufactured by Nisshinbo Chemical Inc., non-volatile content: 40% by mass) were uniformly mixed using a disper to prepare an aqueous surface treatment agent.

[0130] (Examples 2 to 26 and Comparative Examples 1 to 5) An aqueous surface treatment agent was prepared in the same manner as in Example 1, except that 286 parts by mass of an aqueous dispersion of a chain extender of a self-emulsification type isocyanate group-terminated prepolymer neutralized product obtained in Synthesis Examples 2 to 26 and Comparative Synthesis Examples 1 to 5 (35.0% by mass of the chain extender of the self-emulsification type isocyanate group-terminated prepolymer neutralized product) was used instead of the aqueous dispersion of the chain extender of the forced emulsification type isocyanate group-terminated prepolymer obtained in Synthesis Example 1.

[0131] (Comparative Examples 6 to 7) An aqueous surface treatment agent was prepared in the same manner as in Example 1, except that 286 parts by mass of an aqueous dispersion of a self-emulsification type isocyanate group-terminated prepolymer neutralized product obtained in Comparative Synthesis Examples 6 to 7 (35.0% by mass of the chain extender of the self-emulsification type isocyanate group-terminated prepolymer neutralized product) was used instead of the aqueous dispersion of the chain extender of the forced emulsification type isocyanate group-terminated prepolymer obtained in Synthesis Example 1.

[0132] <Production of a PVC leather base material> As a substrate for the PVC leather shown in FIG. 2, a PVC leather substrate (24) was prepared by laminating an intermediate layer (foamed layer) (22) and a PVC-containing skin layer (non-foamed layer) (23) in this order on a base fabric (21).

[0133] First, 100 parts by mass of soft polyvinyl chloride (straight resin with an average degree of polymerization of 1300, trade name "ZEST1300Z" manufactured by Shin-Daiichi PVC Co., Ltd.) were mixed with 65 parts by mass of a first plasticizer (diisodecyl phthalate: DIDP), 5 parts by mass of a second plasticizer (epoxidized soybean oil: trade name "Cabox S-6" manufactured by Kao Corporation), 5 parts by mass of a foaming agent (azodicarbonamide), 10 parts by mass of a filler (calcium carbonate), 7 parts by mass of a flame retardant (antimony trioxide), and 6 parts by mass of a pigment to prepare an intermediate layer (foam layer) forming material (total amount of additives: 93 parts by mass). This intermediate layer forming material was plasticized and calendered to obtain a PVC sheet (I) for forming an intermediate layer (foam layer) having a thickness of 300 μm.

[0134] Separately, a surface layer (non-foamed layer) forming material (total amount of additives: 96 parts by mass) was prepared by blending 100 parts by mass of polyvinyl chloride (straight resin with an average degree of polymerization of 1300, trade name "ZEST1300Z" manufactured by Shin-Daiichi PVC Co., Ltd.) with 75 parts by mass of a first plasticizer (diisodecyl phthalate: DIDP), 5 parts by mass of a second plasticizer (epoxidized soybean oil: trade name "Cabox S-6" manufactured by Kao Corporation), 10 parts by mass of a flame retardant (antimony trioxide), and 6 parts by mass of a pigment. This surface layer forming material was plasticized and calendered to obtain a PVC sheet (II) for forming a surface layer (non-foamed layer) containing PVC having a thickness of 100 μm.

[0135] Next, a pile knitted fabric knitted with 100% polyester 83T crimped yarn was prepared as the base fabric (21), and a two-component polyurethane adhesive was applied onto one surface of this base fabric (21) to form an adhesive layer (not shown). Next, the PVC sheet (I) and the PVC sheet (II) were sequentially arranged on the adhesive layer, and a laminate was obtained by overlapping the PVC sheet (I) and the PVC sheet (II) on the surface of the base fabric (21) via the adhesive layer. After heating the obtained laminate to 100 °C to foam the PVC sheet (I) to form a foamed PVC sheet, squeezing was performed by pressing with a squeezing roll and a rubber roll, and the foamed PVC sheet and the non-foamed PVC sheet (II) were crimped, and the foamed PVC sheet and the base fabric (21) were adhered, so that an intermediate layer (foamed layer) (22) and a skin layer (non-foamed layer) (23) containing PVC were sequentially laminated on the base fabric (21), and a base material (24) for PVC leather having an uneven pattern on the surface was obtained.

[0136] <Production of PVC Leather> On the skin layer (23) of the obtained base material (24) for PVC leather, the aqueous surface treatment agent obtained in the example or comparative example was applied using a 100-mesh gravure coater so that the coating amount after drying was 2 to 5 g / m 2 and the PVC leather provided with a surface treatment layer (25) on the surface of the skin layer (23) of the base material (24) for PVC leather was produced by hot air drying at 125 °C for 3 minutes. The abrasion resistance, flex resistance, plasticizer migration resistance, and alcohol resistance of this PVC leather were evaluated as follows.

[0137] <Abrasion Resistance> Measurements were performed with reference to JASO M403 / 88 / Flat abrasion tester for seat covering fabric materials (Method B). Specifically, the obtained PVC leather was cut to a length of approximately 300 mm x width of 70 mm to prepare a test piece, and a 10 mm thick urethane foam (manufactured by Inoac Corporation under the name "UEI-3") was attached to the back fabric of this test piece with double-sided tape, and the test piece was fixed to the flat abrasion table of the flat abrasion tester (manufactured by Daiei Scientific Instruments Manufacturing Co., Ltd. under the name "PA-2A") without wrinkles. When fixing the test piece, a wire with a diameter of 4.5 mm was placed in the center of the underside of the urethane foam. A frictional element with No. 6 cotton canvas of JIS L3102 (cotton canvas) was set, and the abrasion test was performed by reciprocating 8,000 times on the wire installed on the test piece in parallel with the wire, with a pressing load of 19.6 N including the frictional element, a stroke of 140 mm, and a speed of approximately 60 reciprocations / min. The change in appearance of the surface treatment layer after the abrasion test was confirmed, and the abrasion resistance was evaluated according to the following evaluation criteria. The results are shown in Tables 1 to 3.

[0138] (Evaluation Criteria) Grade 5: No change observed. Grade 4: Slight tears or other damage are observed in the epidermis layer. Grade 3: There are tears or other damage in some areas of the surface layer, but the base fabric on the back is not exposed. Grade 2: After the test has been completed, tears or other damage are observed in the surface layer, exposing the base fabric on the underside. Grade 1: The surface layer breaks down within less than the number of tests, exposing the base fabric on the underside.

[0139] <Crush resistance> The obtained PVC leather was cut to a length of about 120 mm x width of 30 mm to prepare a test piece, and two test pieces in the same direction were stacked with their surface sides facing inwards and attached to the grips of a Scott type rubbing resistance tester (manufactured by Daiei Scientific Instruments Co., Ltd.) with a gap of 30 mm. The gap between the grips was narrowed to adjust the load on the surfaces of the test pieces to 9.8 N, and the test pieces were rubbed 1,000 times with a stroke of 50 mm and a speed of 120 times / min. The appearance change of the test piece surface after the rubbing operation was confirmed, and the rub resistance was evaluated according to the following evaluation criteria. The results are shown in Tables 1 to 3.

[0140] (Evaluation Criteria) Grade 5: No change observed. Grade 4: Slight whitening is observed in the kneaded area. Grade 3: Some whitening is observed in the kneaded area, but no cracks or other defects are observed. Grade 2: Whitening is observed throughout the kneaded area, but no cracks or other defects are observed. Grade 1: Whitening is observed throughout the kneaded area, and cracks are observed in the coating.

[0141] <Resistance to plasticizer migration> The obtained PVC leather was cut to a length of about 100 mm and a width of about 100 mm to prepare a test piece, which was then left to stand for 100 hours in a dryer ("SPHH-201" manufactured by Espec Corporation) set at 110°C. The change in gloss (60° gloss value) before and after leaving the test piece was confirmed, and the plasticizer migration resistance was evaluated according to the following evaluation criteria. The results are shown in Tables 1 to 3.

[0142] (Evaluation Criteria) Grade 5: No change observed. Grade 4: Change in gloss value is 0.1 to 0.2. Grade 3: Change in gloss value is 0.3 to 0.5. Grade 2: Change in gloss value is 0.6 to 1.0. Grade 1: The change in gloss value is greater than 1.0.

[0143] <Alcohol resistance> The alcohol resistance was evaluated according to JIS L0803. Specifically, the obtained PVC leather was cut to a length of about 150 mm and a width of 100 mm to prepare a test piece, which was then set in a crock meter (GESTER INTERNATIONAL's "GT-D05") and the surface of the test piece was wiped 10 times with a 1 kg load using a cotton cloth No. 3 sufficiently soaked in Japanese Pharmacopoeia ethanol (FUJIFILM Wako Pure Chemical Industries, Ltd., 96% ethanol). The appearance change of the test piece surface after the wiping operation was confirmed, and the alcohol resistance was evaluated according to the following evaluation criteria. The results are shown in Tables 1 to 3.

[0144] (Evaluation Criteria) Grade 3: No change observed. Grade 2: A slight change in gloss is observed in the wiped area, but no whitening or tearing is observed. Grade 1: Whitening or tears are observed in the wiped area.

[0145] [Table 1]

[0146] [Table 2]

[0147] [Table 3]

[0148] As shown in Tables 1 to 3, when the surface of a leather substrate having a PVC-containing surface is treated with an aqueous surface treatment agent (Examples 1 to 26) containing (B1) a polycarbonate diol composed only of diols having a linear structure with an even carbon number of 4 to 10 as polyol (B) and (C) a chain extension product of a forced-emulsification type isocyanate-terminated prepolymer or a chain extension product of a neutralized product of a self-emulsification type isocyanate-terminated prepolymer synthesized using a polyhydric alcohol having at least 3 active hydrogens, PVC leather excellent in abrasion resistance, crumple resistance, plasticizer migration resistance, and alcohol resistance can be obtained.

[0149] On the other hand, when other polycarbonate diols were used instead of the (B1) polycarbonate diol (Comparative Examples 1 to 3), even when the (C) polyhydric alcohol having at least three active hydrogens was used, the abrasion resistance and alcohol resistance were inferior to those when only the (B1) polycarbonate diol was used as the (B) polyol (Examples 2 to 5).

[0150] In addition, when a polyether polyol was used instead of the polycarbonate diol (B1) (Comparative Example 4), even when the polyhydric alcohol having at least three active hydrogens (C) was used, the abrasion resistance, crumple resistance, plasticizer migration resistance, and alcohol resistance were inferior to those in the cases where only the polycarbonate diol (B1) was used as the polyol (B) (Examples 2 to 5).

[0151] Furthermore, when the (C) polyhydric alcohol having at least three active hydrogens was not used (Comparative Example 5), even when only the (B1) polycarbonate diol was used as the (B) polyol, it was found that the abrasion resistance, plasticizer migration resistance, and alcohol resistance were inferior to those when the (C) polyhydric alcohol having at least three active hydrogens was used (Example 2).

[0152] In addition, it was found that when the neutralized product of the self-emulsifying isocyanate group-terminated prepolymer was not chain-extended (Comparative Examples 6 to 7), the abrasion resistance, plasticizer migration resistance, and alcohol resistance were inferior to those when the chain was extended (Example 5). [Industrial Applicability]

[0153] As explained above, according to the present invention, it is possible to obtain a surface treatment agent for PVC leather that is excellent in all of abrasion resistance, crumple resistance, plasticizer migration resistance, and alcohol resistance. Therefore, the surface treatment agent for PVC leather of the present invention and PVC leather surface-treated with the same can be suitably used in various industrial fields such as vehicles, furniture, clothing, bags, shoes, sacks, and miscellaneous goods, and further, can be suitably used as a stable and high-quality PVC leather product by providing a surface treatment layer. [Explanation of symbols]

[0154] 11: base fabric, 12: skin layer containing PVC, 13: PVC leather substrate, 14: surface treatment layer, 21: base fabric, 22: intermediate layer, 23: skin layer containing PVC, 24: PVC leather substrate, 25: surface treatment layer

Claims

1. An aqueous surface treatment agent for treating a surface of a leather substrate having a surface containing a vinyl chloride resin, comprising: The aqueous surface treatment agent is (D) a chain extension product of an isocyanate-terminated prepolymer, which is a reaction product of (A) an organic polyisocyanate, (B) a polyol, and (C) a polyhydric alcohol, with a polyamine having two or more amino groups and / or imino groups; or (A) an organic polyisocyanate; (B) a polyol; (E) a compound having an anionic hydrophilic group and at least two active hydrogen atoms; and (C) a polyhydric alcohol. The neutralized prepolymer isocyanate-terminated, and the prepolymer is chain-extended with (D) a polyamine having two or more amino groups and / or imino groups. Including, The (B) polyol contains (B1) a polycarbonate diol composed only of a diol having a linear structure and an even number of carbon atoms of 4 to 10, The (C) polyhydric alcohol contains a polyhydric alcohol having at least three active hydrogens.

1. An aqueous surface treatment agent for vinyl chloride resin leather.

2. 2. The aqueous surface treatment agent for vinyl chloride resin leather according to claim 1, wherein the proportion of the polycarbonate diol (B1) in the polyol (B) is 40% by mass or more.

3. The ratio of the polyhydric alcohol (C) is In the case where the chain extension product is a chain extension product of the isocyanate group-terminated prepolymer, the amount of the chain extension product is, relative to the total amount of the (B) polyol and the (C) polyhydric alcohol, In the case where the chain extension product is a chain extension product of a neutralization product of the isocyanate group-terminated prepolymer, the amount of the chain extension product is, relative to the total amount of the (B) polyol, the (C) polyhydric alcohol, and the (E) compound having an anionic hydrophilic group and at least two active hydrogens, 2. The aqueous surface treatment agent for vinyl chloride resin leather according to claim 1, wherein the content is 0.1 to 1.5% by mass.

4. 2. The aqueous surface treatment agent for vinyl chloride resin leather according to claim 1, wherein the content of free isocyanate groups in the isocyanate-terminated prepolymer is 0.2 to 4.0% by mass.

5. 2. The aqueous surface treatment agent for vinyl chloride resin leather according to claim 1, wherein the organic polyisocyanate (A) is at least one selected from the group consisting of aliphatic polyisocyanates and alicyclic polyisocyanates.

6. A vinyl chloride resin leather comprising a surface treatment layer formed on a surface of a substrate for leather having a vinyl chloride resin-containing surface using the aqueous surface treatment agent for vinyl chloride resin leather according to any one of claims 1 to 5.

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