Water-based urethane resin composition, surface treatment agent, and article

Abstract

To provide an aqueous urethane resin composition containing no tin which can be effectively utilized as a surface treatment agent without impairing various characteristics required as the surface treatment agent, prevents settlement of a filler in the aqueous urethane resin composition and is excellent in storage stability.SOLUTION: An aqueous urethane resin composition contains a urethane resin (A) formed using a non-tin catalyst, water (B) and a filler (C), in which the aqueous urethane resin composition contains an inorganic viscosity modifier (D).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an aqueous urethane resin composition, a surface treatment agent, and an article having a layer formed by the surface treatment agent.

Background Art

[0002] In the manufacturing process of automobile interior leather seats, the surface is finished with a surface treatment agent from the viewpoints of imparting chemical resistance and design properties. The materials used in conventional surface treatment agents have mainly been solvent-based resin compositions containing organic solvents. However, in response to the recent tightening of environmental regulations, the development of aqueous surface treatment agents that substantially do not contain organic solvents has been promoted.

[0003] As such an aqueous surface treatment agent, for example, an aqueous surface treatment agent containing polyurethane having specific mechanical properties, a carbodiimide-based crosslinking agent, and a filler has been disclosed (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The surface treatment agent described in Patent Document 1 above can impart excellent abrasion resistance to the surface of an article and does not impair the flexibility of the article. Further, since it contains a filler, it is also excellent in expressing a matte design. By the way, from the viewpoint of environmental hormones, there is a demand for providing a surface treatment agent that does not use raw materials containing specific substances. For example, tin is one of the substances for which measures are required from the viewpoint of environmental hormones, and it is desired to provide a surface treatment agent that does not contain tin. However, in the polyurethane which is a component of the surface treatment agent described in Patent Document 1 above, a raw material containing tin is used as a catalyst, and in Patent Document 1, the urethane resin composition used for the surface treatment agent contains tin. Therefore, the present inventors produced polyurethane using a non-tin catalyst instead of a tin catalyst, and prepared an aqueous urethane resin composition containing the polyurethane. As a result, when polyurethane produced using a tin catalyst was used, sedimentation of the filler did not occur, but it was found that a surface treatment agent composed of an aqueous urethane resin composition containing polyurethane produced using a non-tin catalyst had poor storage stability due to sedimentation of the filler contained in the aqueous urethane resin composition.

[0006] Therefore, an object of the present invention is to provide an aqueous urethane resin composition not containing tin, which can be effectively used as a surface treatment agent without impairing various properties required for a surface treatment agent, can prevent sedimentation of the filler in the aqueous urethane resin composition, and has excellent storage stability.

Means for Solving the Problems

[0007] As a result of intensive studies to solve the above problems, the present inventors have found that by incorporating an inorganic viscosity modifier into an aqueous urethane resin composition, even when polyurethane formed using a non-tin catalyst is incorporated without impairing various properties required for a surface treatment agent, a filler does not sediment and an aqueous urethane resin composition having excellent storage stability can be obtained, thus completing the present invention.

[0008] That is, the present invention includes the following aspects. [1] An aqueous urethane resin composition containing a urethane resin (A) formed using a non-tin catalyst, water (B), and a filler (C), wherein the aqueous urethane resin composition contains an inorganic viscosity modifier (D). [2] The aqueous urethane resin composition according to [1], wherein the aqueous urethane resin composition further contains a crosslinking agent (E). [3] The aqueous urethane resin composition according to [1] or [2], wherein the non-tin catalyst is bismuth carboxylate. [4] The aqueous urethane resin composition according to any one of [1] to [3], wherein the filler (C) is silica. [5] The aqueous urethane resin composition according to any one of [2] to [4], wherein the crosslinking agent (E) is a carbodiimide-based crosslinking agent. [6] The aqueous urethane resin composition according to any one of [1] to [5], wherein the inorganic viscosity modifier (D) is selected from any one of montmorillonite, beidellite, nontronite, saponite, hectorite, stibnite, mica, and bentonite. [7] A surface treatment agent containing the aqueous urethane resin composition according to any one of [1] to [6]. [8] An article having a layer formed by the surface treatment agent according to [7]. [Advantages of the Invention]

[0009] The present invention provides an aqueous urethane resin composition that does not contain tin, can be effectively used as a surface treatment agent without impairing the various properties required for a surface treatment agent, can prevent sedimentation of the filler in the aqueous urethane resin composition, and has excellent storage stability. [Embodiments for Carrying Out the Invention]

[0010] Hereinafter, the present invention will be described in detail. It should be noted that the description of the constituent elements described below is an exemplification for explaining the present invention, and the present invention is not limited to these contents.

[0011] (Aqueous Urethane Resin Composition) The aqueous urethane resin composition of the present invention contains a urethane resin (A) formed using a non-tin catalyst, water (B), a filler (C), and an inorganic viscosity modifier (D). Further, as a preferred embodiment of the aqueous urethane resin composition of the present invention, the aqueous urethane resin composition further contains a crosslinking agent (E). The following describes each component constituting the aqueous urethane resin composition.

[0012] <Urethane resin (A)> The urethane resin (A) is formed using a non-tin catalyst.

[0013] The urethane resin (A) can be dispersed in water (B). For example, a urethane resin having a hydrophilic group such as an anionic group, a cationic group, or a nonionic group; a urethane resin forcibly dispersed in water (B) with an emulsifier, etc. can be used. These urethane resins (A) may be used alone or in combination of two or more.

[0014] As a method for obtaining a urethane resin having an anionic group, for example, a method of using one or more compounds selected from the group consisting of a compound having a carboxyl group and a compound having a sulfonyl group as a raw material can be mentioned. In the present invention, it is preferable to use a compound having a carboxyl group as a raw material.

[0015] Examples of the compound having a carboxyl group include 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolpropionic acid, 2,2-valeric acid, etc. These compounds may be used alone or in combination of two or more.

[0016] Examples of the compound having a sulfonyl group include 3,4-diaminobutanesulfonic acid, 3,6-diamino-2-toluenesulfonic acid, 2,6-diaminobenzenesulfonic acid, N-(2-aminoethyl)-2-aminoethylsulfonic acid, etc. These compounds may be used alone or in combination of two or more.

[0017] The above carboxyl group and sulfonyl group may be partially or entirely neutralized with a basic compound in the resin composition. Examples of the basic compound include organic amines such as ammonia, triethylamine, pyridine, and morpholine; alkanolamines such as monoethanolamine and dimethylethanolamine; and metal base compounds containing sodium, potassium, lithium, calcium, etc.

[0018] As a method for obtaining the urethane resin having the above cationic group, for example, a method of using one or more compounds having an amino group as raw materials can be mentioned.

[0019] Examples of the compound having an amino group include compounds having primary and secondary amino groups such as triethylenetetramine and diethylenetriamine; N-alkyldialkanolamines such as N-methyldiethanolamine and N-ethyldiethanolamine, and compounds having a tertiary amino group such as N-methyldiaminoethylamine and N-ethyldiaminoethylamine. These compounds may be used alone or in combination of two or more.

[0020] As a method for obtaining the urethane resin having the above nonionic group, for example, a method of using one or more compounds having an oxyethylene structure as raw materials can be mentioned.

[0021] Examples of the compound having an oxyethylene structure include polyether polyols having an oxyethylene structure such as polyoxyethylene glycol, polyoxyethylene polyoxypropylene glycol, and polyoxyethylene polyoxytetramethylene glycol. These compounds may be used alone or in combination of two or more.

[0022] As the amount of the raw materials used for producing the urethane resin having the above hydrophilic group, from the viewpoint of obtaining more excellent chemical resistance, abrasion resistance, weather resistance, and hydrolysis resistance, it is preferably in the range of 0.1 to 15% by mass in the raw materials of the urethane resin (A), more preferably in the range of 1 to 10% by mass, and still more preferably in the range of 1.5 to 7% by mass.

[0023] As the emulsifier that can be used when obtaining the urethane resin forcibly dispersed in water (B), for example, nonionic emulsifiers such as polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl ether, polyoxyethylene styryl phenyl ether, polyoxyethylene sorbitol tetraoleate, polyoxyethylene-polyoxypropylene copolymer; fatty acid salts such as sodium oleate, alkyl sulfate esters, alkylbenzene sulfonates, alkyl sulfosuccinates, naphthalene sulfonates, polyoxyethylene alkyl sulfates, alkane sulfonate sodium salts, sodium alkyl diphenyl ether sulfonate salts and other anionic emulsifiers; cationic emulsifiers such as alkylamine salts, alkyltrimethylammonium salts, alkyldimethylbenzylammonium salts, etc. can be used. These emulsifiers may be used alone or in combination of two or more.

[0024] As the urethane resin (A), specifically, for example, the reaction products of the raw materials used for producing the urethane resin having the above hydrophilic group, polyisocyanate (a1), polyol (a2), and chain extender (a3) can be used. These reactions can use known urethanization reactions.

[0025] Examples of the polyisocyanate (a1) include aromatic polyisocyanates such as phenylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, naphthalene diisocyanate, polymethylene polyphenyl polyisocyanate, and carbodiimidized diphenylmethane polyisocyanate; aliphatic or alicyclic polyisocyanates such as hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, dimer acid diisocyanate, and norbornene diisocyanate. These polyisocyanates may be used alone or in combination of two or more.

[0026] As the polyisocyanate (a1), it is preferable to use an alicyclic polyisocyanate from the viewpoint of obtaining more excellent chemical resistance, abrasion resistance, and weather resistance. More preferably, a polyisocyanate having one or more structures in which at least the nitrogen atom of the isocyanate group is directly connected to a cyclohexane ring is used. Even more preferably, isophorone diisocyanate and / or dicyclohexylmethane diisocyanate is used. Further, the amount of the alicyclic polyisocyanate used is preferably 30% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass or more in the polyisocyanate (a1) from the viewpoint of obtaining more excellent chemical resistance, abrasion resistance, and weather resistance.

[0027] In addition, when the aqueous urethane resin composition of the present invention is used as a surface treatment agent and higher light resistance is required, it is preferable to use the alicyclic polyisocyanate and the aliphatic polyisocyanate in combination as the polyisocyanate (a1). As the aliphatic polyisocyanate, it is preferable to use hexamethylene diisocyanate. The content of the alicyclic polyisocyanate in the polyisocyanate (a1) at this time is preferably 30% by mass or more, more preferably 40% by mass or more, and still more preferably 50% by mass or more.

[0028] The amount of the polyisocyanate (a1) used is preferably in the range of 5 to 50% by mass, more preferably in the range of 15 to 40% by mass, and still more preferably in the range of 20 to 37% by mass in the raw materials of the urethane resin (A) in terms of obtaining more excellent chemical resistance, abrasion resistance, and weather resistance.

[0029] As the polyol (a2), for example, polyether polyol, polyester polyol, polyacrylic polyol, polycarbonate polyol, polybutadiene polyol, etc. can be used. These polyols can be used alone or in combination of two or more. Among these, it is preferable to use polycarbonate polyol in terms of obtaining more excellent chemical resistance, abrasion resistance, and weather resistance.

[0030] As the polycarbonate polyol, for example, a reaction product of a carbonate ester and / or phosgene and a compound having two or more hydroxyl groups can be used.

[0031] As the carbonate ester, for example, dimethyl carbonate, diethyl carbonate, diphenyl carbonate, ethylene carbonate, propylene carbonate, etc. can be used. These compounds can be used alone or in combination of two or more.

[0032] Examples of the compound having two or more hydroxyl groups include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,5-hexanediol, 3-methyl-1,5-pentanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,8-nonanediol, 2-ethyl-2-butyl-1,3-propanediol, 1,10-decanediol, 1,12-dodecanediol, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, trimethylolpropane, 3-methylpentanediol, neopentyl glycol, trimethylolethane, glycerin, etc. These compounds may be used alone or in combination of two or more. Among these, from the viewpoint of obtaining more excellent chemical resistance, abrasion resistance, and weather resistance, it is preferable to use one or more compounds selected from the group consisting of 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, 3-methylpentanediol, and 1,10-decanediol, and 1,6-hexanediol is more preferable.

[0033] From the viewpoint of obtaining more excellent chemical resistance, abrasion resistance, and weather resistance, the amount of the polycarbonate polyol used is preferably 85% by mass or more, more preferably 90% by mass or more, and still more preferably 95% by mass or more in the polyol (a2).

[0034] From the viewpoint of obtaining more excellent chemical resistance, mechanical strength, abrasion resistance, and weather resistance, the number average molecular weight of the polycarbonate polyol is preferably in the range of 100 to 100,000, more preferably in the range of 150 to 10,000, and still more preferably in the range of 200 to 2,500. The number average molecular weight of the polycarbonate polyol indicates the value measured by the end group quantification method.

[0035] The number average molecular weight of the above polyol (a2) other than the above polycarbonate polyol is preferably in the range of 500 to 100,000, more preferably in the range of 700 to 50,000, and even more preferably in the range of 800 to 10,000 from the viewpoint of obtaining even better weather resistance. The number average molecular weight of the above polyol (a2) represents the value measured by the end group quantification method.

[0036] The amount of the above polyol (a2) used is preferably in the range of 30 to 80% by mass, more preferably in the range of 40 to 75% by mass, and even more preferably in the range of 50 to 70% by mass in the raw materials of the urethane resin (A).

[0037] Examples of the above chain extender (a3) include those having a number average molecular weight in the range of 50 to 450 (excluding the above polycarbonate polyol). Specifically, chain extenders having an amino group such as ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2,5-dimethylpiperazine, isophoronediamine, 1,2-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 4,4'-dicyclohexylmethanediamine, 3,3'-dimethyl-4,4'-dicyclohexylmethanediamine, 1,4-cyclohexanediamine, hydrazine, etc.; chain extenders having a hydroxyl group such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, hexamethylene glycol, sucrose, methylene glycol, glycerin, sorbitol, bisphenol A, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxydiphenyl ether, trimethylolpropane, etc. These chain extenders may be used alone or in combination of two or more.

[0038] As the chain extender (a3), among those described above, from the viewpoint of obtaining even more excellent chemical resistance, mechanical strength, abrasion resistance, and weather resistance, it is preferable to use a chain extender having an amino group, more preferably piperazine and / or hydrazine. The total amount of piperazine and hydrazine is preferably 30% by mass or more, more preferably 50% by mass or more, still more preferably 60% by mass or more, and particularly preferably 80% by mass or more in the chain extender (a3). Further, as the chain extender (a3), it is preferable that the average functionality is less than 3, and more preferably less than 2.5.

[0039] The amount of the chain extender (a3) used is preferably in the range of 0.5 to 10% by mass, more preferably in the range of 0.7 to 5% by mass, and still more preferably in the range of 0.9 to 2.3% by mass in the raw materials of the urethane resin (A) from the viewpoint of obtaining even more excellent chemical resistance, mechanical strength, abrasion resistance, and weather resistance.

[0040] Examples of the method for producing the urethane resin (A) include a method of producing a urethane prepolymer having an isocyanate group by reacting the above polyisocyanate (a1), the above polyol (a2), and the raw materials used for producing the urethane resin having a hydrophilic group, and then reacting the urethane prepolymer with the above chain extender (a3); a method of charging and reacting the above polyisocyanate (a1), the above polyol (a2), the raw materials used for producing the urethane resin having a hydrophilic group, and the above chain extender (a3) all at once. These reactions can be carried out, for example, at 50 to 100°C for 3 to 10 hours.

[0041] The molar ratio [(isocyanate group) / (hydroxyl group and amino group)] of the total of the hydroxyl groups of the raw materials used for producing the urethane resin having a hydrophilic group, the hydroxyl groups of the above polyol (a2), and the hydroxyl groups and amino groups of the above chain extender (a3) to the isocyanate groups of the above polyisocyanate (a1) is preferably in the range of 0.8 to 1.2, and more preferably in the range of 0.9 to 1.1.

[0042] When producing the urethane resin (A), it is preferable to deactivate the isocyanate groups remaining in the urethane resin (A). When deactivating the isocyanate groups, it is preferable to use an alcohol having one hydroxyl group such as methanol. The amount of the alcohol used is preferably in the range of 0.001 to 10 parts by mass with respect to 100 parts by mass of the urethane resin (A).

[0043] Also, when producing the urethane resin (A), an organic solvent may be used. Examples of the organic solvent include ketone compounds such as acetone and methyl ethyl ketone; ether compounds such as tetrahydrofuran and dioxane; acetate ester compounds such as ethyl acetate and butyl acetate; nitrile compounds such as acetonitrile; amide compounds such as dimethylformamide and N-methylpyrrolidone, etc. These organic solvents may be used alone or in combination of two or more. In addition, the organic solvent is preferably finally removed by a distillation method or the like.

[0044] When producing the urethane resin (A), a catalyst is used, but in the present invention, a tin catalyst is not used. In the present invention, the urethane resin (A) is produced using a non-tin catalyst. The non-tin catalyst is not particularly limited and can be appropriately used according to the purpose. Examples thereof include bismuth carboxylate, bismuth halide, bismuth phosphate, bismuth nitrate, bismuth sulfate, etc. Among them, from the viewpoints of miscibility and reactivity, it is preferable to use a non-tin catalyst of bismuth carboxylate such as bismuth octylate, bismuth neodecanoate, bismuth naphthenate, etc.

[0045] The content of urethane bonds in the urethane resin (A) is preferably in the range of 980 to 4,000 mmol / kg, more preferably in the range of 1,000 to 3,500 mmol / kg, still more preferably in the range of 1,100 to 3,000 mmol / kg, and particularly preferably in the range of 1,150 to 2,500 mmol / kg, from the viewpoint of obtaining even more excellent chemical resistance, abrasion resistance, and weather resistance. The content of urethane bonds in the urethane resin (A) represents a value calculated from the charged amounts of the above polyisocyanate (a1), the above polyol (a2), the raw materials used for producing the urethane resin having the above hydrophilic group, and the above chain extender (a3).

[0046] The content of urea bonds in the urethane resin (A) is preferably in the range of 315 to 850 mmol / kg, more preferably in the range of 350 to 830 mmol / kg, still more preferably in the range of 400 to 800 mmol / kg, and particularly preferably in the range of 410 to 770 mmol / kg, from the viewpoint of obtaining even more excellent chemical resistance, abrasion resistance, and weather resistance. The content of urea bonds in the urethane resin (A) represents a value calculated from the charged amounts of the above polyisocyanate (a1), the above polyol (a2), the raw materials used for producing the urethane resin having the above hydrophilic group, and the above chain extender (a3).

[0047] The content of the alicyclic structure in the urethane resin (A) is preferably in the range of 500 to 3,000 mmol / kg, more preferably in the range of 600 to 2,900 mmol / kg, and still more preferably in the range of 700 to 2,700 mmol / kg, from the viewpoint of obtaining even more excellent chemical resistance, abrasion resistance, and weather resistance. The content of the alicyclic structure in the urethane resin (A) represents a value calculated from the charged amounts of the above polyisocyanate (a1), the above polyol (a2), the raw materials used for producing the urethane resin having the above hydrophilic group, and the above chain extender (a3).

[0048] The content of the urethane resin (A) is preferably in the range of 3 to 50% by mass, more preferably in the range of 5 to 30% by mass, in the aqueous urethane resin composition from the viewpoints of coatability, workability, and storage stability.

[0049] The urethane resin (A) according to the present invention is preferably a urethane resin showing acidity.

[0050] <Water (B)> As the water (B), ion-exchanged water, distilled water, tap water, purified and sterilized industrial water, well water, etc. can be used. The content of the water (B) is preferably in the range of 30 to 95% by mass, more preferably in the range of 50 to 90% by mass, in the aqueous urethane resin composition from the viewpoints of coatability, workability, and storage stability.

[0051] <Filler (C)> In order to impart a matte feeling to the coating film so that the aqueous urethane resin composition of the present invention can be effectively used as a surface treatment agent, the aqueous urethane resin composition contains a filler (C).

[0052] As the filler (C), for example, silica, organic beads, calcium carbonate, magnesium carbonate, barium carbonate, talc, aluminum hydroxide, calcium sulfate, kaolin, mica, asbestos, mica, calcium silicate, aluminosilicate, etc. can be used. These fillers may be used alone or in combination of two or more.

[0053] As the silica, for example, dry silica, wet silica, etc. can be used. Among these, dry silica is preferable because of its high scattering effect and wide adjustment range of the gloss value. The average particle diameter of these silica particles is preferably in the range of 2 to 14 μm, more preferably in the range of 3 to 12 μm. The average particle diameter of the silica particles indicates the particle diameter (the particle diameter at D50 in the particle size distribution) when the integrated amount occupies 50% in the integrated particle amount curve of the particle size distribution measurement result.

[0054] As the organic beads, for example, acrylic beads, urethane beads, silicone beads, olefin beads, etc. can be used.

[0055] The filler (C) according to the present invention is preferably a filler whose surface exhibits basicity or weak basicity.

[0056] The amount of the filler (C) used can be appropriately determined according to the matting feeling to be imparted. For example, it is preferably in the range of 0.1 to 10% by mass, more preferably in the range of 0.2 to 5% by mass in the aqueous urethane resin composition.

[0057] <Inorganic viscosity modifier (D)> Even in an aqueous urethane resin composition containing polyurethane produced using a non-tin catalyst, an inorganic viscosity modifier (D) is contained in the aqueous urethane resin composition so that the filler does not settle and the aqueous urethane resin composition has excellent storage stability. The inorganic viscosity modifier (D) has an effect as a thickener.

[0058] Examples of the inorganic viscosity modifier (D) include montmorillonite, beidellite, nontronite, saponite, hectorite, stibnite, mica, and bentonite. These can be used alone or in combination of two or more. The inorganic viscosity modifier (D) may be any of natural products, synthetic products, and processed products with organic substances, etc. Also, those in a state diluted with a diluting medium such as an organic solvent or water may be used. Among them, synthetic hectorite can be preferably used from the viewpoint of less coloring, etc.

[0059] The inorganic viscosity modifier (D) often shows an effect in a trace amount in terms of storage stability, but the content may be adjusted in consideration of coatability, workability, etc. The content of the inorganic viscosity modifier (D) is preferably in the range of 0.01 to 1% by mass, more preferably in the range of 0.01 to 0.5% by mass in the aqueous urethane resin composition.

[0060] When polyurethane is produced using a non-tin catalyst, the inventors have speculated that an organic acid contained as an impurity in the non-tin catalyst may replace polyurethane or the like adsorbed on a filler (e.g., silica particles) and cause the filler to settle. Therefore, by including an inorganic viscosity modifier in the aqueous urethane resin composition, it is considered that the sedimentation of the filler may be suppressed by the sol-gel action of the inorganic viscosity modifier. In addition, it is considered that the inorganic viscosity modifier also contributes to the suppression of filler sedimentation by becoming a weak base in water and suppressing a decrease in the pH of the surface treatment agent solution.

[0061] <Crosslinking agent (E)> In order to improve the mechanical strength of the coating film so that the aqueous urethane resin composition of the present invention can be effectively used as a surface treatment agent, the aqueous urethane resin composition contains a crosslinking agent (E). As the crosslinking agent (E), for example, an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, a carbodiimide-based crosslinking agent, an oxazolidine-based crosslinking agent, an oxazoline-based crosslinking agent, an aziridine-based crosslinking agent, a melamine-based crosslinking agent, etc. can be used. These crosslinking agents may be used alone or in combination of two or more. Among them, from the viewpoints of safety to the human body and the environment, and the balance between reactivity and pot life, the crosslinking agent (E) is preferably a carbodiimide-based crosslinking agent.

[0062] The amount of the crosslinking agent (E) used is preferably in the range of 0.3 to 9% by mass, more preferably in the range of 0.5 to 5% by mass, in the aqueous urethane resin composition as an active ingredient, for example.

[0063] <Other components> The aqueous urethane resin composition of the present invention may contain other components (additives) as necessary in addition to the above-described urethane resin (A), water (B), filler (C), and inorganic viscosity modifier (D), or the above-described urethane resin (A), water (B), filler (C), inorganic viscosity modifier (D), and crosslinking agent (E).

[0064] Other components include, for example, pH adjusters, dispersants, silicone additives, thickeners (viscosity modifiers), emulsifiers, defoamers, leveling agents, viscoelasticity modifiers, defoamers, wetting agents, preservatives, plasticizers, penetrants, fragrances, bactericides, acaricides, fungicides, ultraviolet absorbers, antioxidants, antistatic agents, flame retardants, dyes, pigments (e.g., titanium white, red iron oxide, phthalocyanine, carbon black, permanent yellow, etc.), and the like. These other components may be used alone or in combination of two or more.

[0065] Bases such as amines may be contained as pH adjusters in the aqueous urethane resin composition of the present invention. It is considered that the combined use of a pH adjuster is effective in suppressing the sedimentation of the filler. In addition, anionic, nonionic, or salt-type dispersants may be contained in the aqueous urethane resin composition of the present invention. This dispersant is also considered to be effective in suppressing the sedimentation of the filler.

[0066] A silicone additive (silicone compound) may be contained in the aqueous urethane resin composition of the present invention. There are no particular restrictions on the silicone additive, and it can be appropriately selected according to the purpose. For example, polydimethylsiloxane, polymethylphenylsiloxane, polymethylhydrogensiloxane, polymethylphenylhydrogensiloxane; modified products thereof; copolymers of these silicone compounds and acrylics, etc. can be used. These silicone compounds may be used alone or in combination of two or more. Among these, polydimethylsiloxane is preferably used from the viewpoint of obtaining more excellent abrasion resistance.

[0067] From the viewpoint of affinity with water (B), the silicone additive preferably takes the form of an emulsion dispersed in water (B). In such a case, a known surfactant may be contained.

[0068] The content (solid content) of the silicone additive is preferably in the range of 0.01 to 10% by mass, more preferably in the range of 0.1 to 7% by mass, and still more preferably in the range of 0.5 to 5% by mass from the viewpoint of obtaining further excellent abrasion resistance.

[0069] The aqueous urethane resin composition of the present invention may contain a viscosity modifier (thickener) different from the inorganic viscosity modifier (D). Examples of the viscosity modifier (thickener) that can be used include cellulose derivatives such as hydroxyethyl cellulose, methyl cellulose, and carboxymethyl cellulose, polyacrylates, polyvinylpyrrolidone, urethane-based, polyether-based, and the like. Among these, a urethane-based associative thickener is preferable from the viewpoint of showing good compatibility with the urethane resin (A).

[0070] The aqueous urethane resin composition of the present invention may be a one-component type in which all components are premixed, or a two-component type in which the main agent composition and the curing agent composition are separated and these compositions are mixed before use.

[0071] (Properties of the aqueous urethane resin composition) The aqueous urethane resin composition of the present invention containing the above-described respective components can exhibit various properties required for a surface treatment agent, for example, can impart excellent abrasion resistance to the surface of an article, does not impair the flexibility of the article, and is excellent in matte feeling (glossiness), and can be effectively used as a surface treatment agent. Further, the aqueous urethane resin composition of the present invention is an aqueous urethane resin composition excellent in storage stability that does not cause sedimentation of the filler even if it contains a polyurethane produced using a non-tin catalyst.

[0072] (Surface treatment agent) The surface treatment agent of the present invention contains the above-described aqueous urethane resin composition of the present invention. The aqueous urethane resin composition of the present invention can provide a film excellent in chemical resistance. Therefore, the aqueous urethane resin composition of the present invention can be suitably used as a surface treatment agent (paint) to be applied to various articles such as synthetic leather, polyvinyl chloride (PVC) leather, thermoplastic olefin resin (TPO) leather, dashboard, and instrument panel.

[0073] The article of the present invention has a layer formed by a surface treatment agent.

[0074] Specific examples of the article include, for example, synthetic leather, artificial leather, natural leather, automotive interior seats using polyvinyl chloride (PVC) leather, sports shoes, clothing, furniture, thermoplastic olefin (TPO) leather, dashboard, instrument panel, and the like.

[0075] The thickness of the layer formed by the surface treatment agent is, for example, in the range of 0.1 to 100 μm.

Examples

[0076] Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. In the examples, descriptions such as "parts" and "%" mean descriptions based on mass unless otherwise specified.

[0077] (Production Example 1) 558 parts of methyl ethyl ketone, 964 parts of polycarbonate diol (based on 1,6 - hexanediol with a number average molecular weight of 2000), 43 parts of dimethylolpropionic acid, 295 parts of dicyclohexylmethane diisocyanate, and 0.05 part of bismuth carboxylate were sequentially charged into a four - necked flask and reacted at 70°C for 4 hours. After cooling to 40°C, 33 parts of triethylamine was charged, and while continuously stirring, 2,516 parts of water was added dropwise over 1 hour, and then 19 parts of ethylenediamine was added and reacted at 40°C for another 1 hour. Methyl ethyl ketone was distilled off under reduced pressure to obtain a polyurethane - containing liquid with a non - volatile content of 35% containing polyurethane (A).

[0078] (Production Example 2) 970 parts of water was put into a stainless-steel kettle, and while stirring with a small disperser, a powder of an inorganic viscosity modifier mainly composed of 30 parts of synthetic hectorite was divided and added over 30 minutes. Subsequently, stirring was continued for 30 minutes to obtain a diluted solution of the inorganic viscosity modifier (D).

[0079] (Example 1) A polyurethane-containing liquid containing 350 parts of polyurethane (A), 550 parts of water (B), 20 parts of a dry silica-based matting agent (C), 20 parts of a diluted solution of an inorganic viscosity modifier (D), 30 parts of a polymer-based dispersant (active ingredient 40%), and 30 parts of a polydimethylsiloxane aqueous dispersion (active ingredient 65%) were stirred with a small disperser for 30 minutes to obtain an aqueous urethane resin composition (1-1). 3 parts of a carbodiimide-based crosslinking agent (E) (active ingredient 40%) was added to 100 parts of the aqueous urethane resin composition (1-1), and stirred with a small disperser for 2 minutes to obtain an aqueous urethane resin composition (1-2). The aqueous urethane resin composition (1-1) was used as an aqueous surface treatment agent (1), and the aqueous urethane resin composition (1-2) was used as a paint (1).

[0080] Using the aqueous urethane resin composition obtained in Example 1, and the aqueous surface treatment agent and paint composed of the aqueous urethane resin composition, each evaluation described below was carried out. The results are shown in Table 1 below.

[0081] <Evaluation of storage stability> The aqueous urethane resin composition (1-1) was filled to about the 9th minute in a 1-liter plastic bottle and allowed to stand at room temperature for 4 weeks, and then the bottom of the bottle was scooped with a spatula to observe the presence or absence of sedimentation.

[0082] <Evaluation of matting feeling> The aqueous urethane resin composition (1-2) was applied onto urethane synthetic leather cut into A4 size, dried, and further allowed to stand for 3 days to prepare a sample for evaluation. The gloss value was measured at a measurement angle of 60° using a gloss meter Microtri gloss (manufactured by BYK). Coating conditions: bar coater with a wet film thickness of 50 μm Drying conditions: For 2 minutes in a gear oven set at 120°C

[0083] <Evaluation of Abrasion Resistance> A test piece approximately 7 cm in width and 30 cm in length was cut out from the sample for evaluation and tested using a flat abrasion tester (manufactured by Intec). A stainless steel wire with a diameter of 4.5 mm, a cushioning material with a thickness of 10 mm (compression stress 1 N / square cm), and the test piece were placed on the stage in that order, fixed so that the test piece would not slack, a weight of 2 kg was placed on the friction head equipped with No. 6 canvas, and friction was applied at an amplitude of 140 mm and 60 reciprocations per minute. The abrasion resistance was evaluated by the number of reciprocations until the urethane resin layer of the synthetic leather was destroyed and the fabric was exposed.

[0084] <Evaluation of Flexibility> A test piece approximately 2.5 cm in width and 12 cm in length was cut out from the sample for evaluation and tested using a Scott crumpling tester (manufactured by Intec). With the urethane resin layer of the synthetic leather facing outwards, the flexibility was evaluated by comparing the state after crumpling 2000 times under a load of 1 kg.

[0085] (Comparative Example 1) An aqueous urethane resin composition (2-1) was obtained in the same manner as in Example 1 using 350 parts of a polyurethane (A)-containing polyurethane-containing liquid, 570 parts of water (B), 20 parts of a dry silica-based matting agent (C), 30 parts of a polymer-based dispersant (active ingredient 40%), and 30 parts of a polydimethylsiloxane aqueous dispersion (active ingredient 65%). An aqueous urethane resin composition (2-2) was obtained in the same manner as in Example 1, except that 100 parts of the aqueous urethane resin composition (2-1) was used instead of 100 parts of the aqueous urethane resin composition (1-1). The aqueous urethane resin composition (2-1) was used as the aqueous surface treatment agent (2), and the aqueous urethane resin composition (2-2) was used as the paint (2). The same evaluations as in Example 1 were also performed on the aqueous urethane resin composition of Comparative Example 1, and the aqueous surface treatment agent and the paint. The results are shown in Table 1 below.

[0086] (Production Example 2) A polyurethane-containing liquid with a non-volatile content of 35% containing polyurethane (G) was obtained in the same manner as in Production Example 1, except that 0.05 part of dibutyltin dilaurate was used instead of 0.05 part of bismuth carboxylate.

[0087] (Comparative Example 2) An aqueous urethane resin composition (3-1) was obtained in the same manner as in Comparative Example 1, except that a polyurethane-containing liquid containing 350 parts of polyurethane (G) was used instead of the polyurethane-containing liquid containing 350 parts of polyurethane (A). An aqueous urethane resin composition (3-2) was obtained in the same manner as in Example 1, except that 100 parts of the aqueous urethane resin composition (3-1) was used instead of 100 parts of the aqueous urethane resin composition (1-1). The aqueous urethane resin composition (3-1) was used as the aqueous surface treatment agent (3), and the aqueous urethane resin composition (3-2) was used as the paint (3). The same evaluation as in Example 1 was also performed on the aqueous urethane resin composition of Comparative Example 2, and the aqueous surface treatment agent and the paint. The results are shown in Table 1 below.

[0088]

Table 1

[0089] From the above examples, the aqueous urethane resin composition of the present invention containing the inorganic viscosity modifier (D) can impart excellent abrasion resistance to the surface of an article, does not impair the flexibility of the article, and is a suitable aqueous urethane resin composition that can be preferably used as a surface treatment agent excellent in a matte feeling (glossiness). It was confirmed that the composition is a tin-free aqueous urethane resin composition that prevents sedimentation of the filler and has excellent storage stability.

Claims

1. An aqueous urethane resin composition containing a urethane resin (A) formed using a non-tin catalyst, water (B), a filler (C), an inorganic viscosity modifier (D), and a silicone additive, wherein the filler (C) is silica, the inorganic viscosity modifier (D) is selected from any one of montmorillonite, beidellite, nontronite, saponite, hectorite, stibnite, and bentonite, the content of the inorganic viscosity modifier (D) is in the range of 0.01 to 0.5% by mass in the aqueous urethane resin composition.

2. The aqueous urethane resin composition according to Claim 1, wherein the amount of the filler (C) used is in the range of 0.1 to 10% by mass in the aqueous urethane resin composition.

3. The aqueous urethane resin composition according to Claim 1 or 2, wherein the non-tin catalyst is bismuth carboxylate.

4. The aqueous urethane resin composition according to any one of Claims 1 to 3, further containing a crosslinking agent (E).

5. The aqueous urethane resin composition according to Claim 4, wherein the crosslinking agent (E) is a carbodiimide-based crosslinking agent.

6. The aqueous urethane resin composition according to any one of Claims 1 to 5, wherein the content (solid content) of the silicone additive is in the range of 0.01 to 10% by mass.

7. A surface treatment agent containing the aqueous urethane resin composition according to any one of Claims 1 to 6.

8. An article having a layer formed by the surface treatment agent according to Claim 7.

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