CROSS-REFERENCE TO RELATED APPLICATION

This non-provisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No. 2019-025022 filed in Japan on Feb. 15, 2019, the entire contents of which are hereby incorporated by reference.

TECHNICAL FIELD

The present invention relates to a thermoplastic urethane resin molded product made of a thermoplastic urethane resin composition containing a silicone acrylic graft copolymer resin.

BACKGROUND ART

Conventionally, methane resin molded products have been widely used for stationery, toys, home appliances, car seats, furniture, clothing, shoes, bags, sanitary goods, outdoor tents and the like. When used in these applications, the urethane resin molded product needs to have excellent tactile sensation and lubricity, and in view of productivity, it needs mold releasability when molded.

However, when the urethane resin is used alone, the slidability and the like are insufficient, and it is often impossible to sufficiently cope with a field requiring abrasion resistance, and further performance improvement has been demanded.

Furthermore, as a method for improving the abrasion resistance and lubricity of a urethane resin molded product, it is known that a silicone component such as silicone oil or silicone powder is kneaded into the urethane resin when the resin molded product is produced. For example, in JP-A 2007-138326 (Patent Document 1), acrylic-silicone copolymer particles are kneaded with urethane elastomer to successfully improve the abrasion resistance of synthetic leather. However, in this case, since the silicone powder is kneaded into the urethane resin, the manufacturing process becomes complicated. In addition, in order to obtain abrasion resistance performance, it is necessary to increase the amount of acrylic-silicone copolymer particles added, and if this amount is large, the transparency of the methane resin molded product cannot be maintained.

In order to solve this problem, there is a method of coating a resin or the like on a leather surface such as natural leather or synthetic leather. JP-A 2007-314919 (Patent Document 2) discloses that abrasion resistance is improved by applying a surface finishing agent obtained by adding a crosslinking agent and a polyether-modified silicone to an aqueous polyurethane resin to artificial leather. However, in this case, since the hydrophilicity of the surface finishing agent becomes strong, it is concerned that when a dark-colored beverage such as coffee and the like or a liquid adheres, the liquid color moves to the leather, or when the clothes are rubbed, the antifouling property of the leather surface may be lost, such as the color of the fiber moving to the leather.

In order to solve the above problem, for example, in JP-A 2002-363403 (Patent Document 3), there is a proposal to try to improve slidability by using a specific polyolefin resin in combination with a fluorine-based or silicone-based lubricant. However, the combined use with the modified polyolefin resin is indispensable in this technique. In addition, there are such problems that it is difficult to achieve compatibility and that interfacial peeling is likely to occur since the amount added to the polyamide resin is large. Furthermore, there is room for improvement in that compatibility is poor, interfacial peeling is likely to occur, and molding is difficult since a fluorine-based or silicone-based lubricant is blended.

Furthermore, as a method for improving the antifouling property of leather, a method of coating a resin or the like on the leather surface is known. JP-A 2010-241963 (Patent Document 4) discloses that a resin such as an acrylic resin, an acrylic silica resin, and an acrylic polysiloxane resin is blended with a silicone-based tactile agent and applied to natural leather. In addition, Japanese Patent Publication No. 2008-308785 (Patent Document 5) discloses that a silicone resin film is formed on the surface of synthetic leather made of an urethane resin. However, the problems are that the refractive index of the silicone resin is low, and the refractive index is far away from those of urethane resin and vinyl chloride resin, so that the film becomes turbid and whitened. The present inventor has also studied the silicone acrylic graft copolymer resin emulsion in the invention described in JP-A 2016-138242 (Patent Document 6) and discloses that the problem of whitening does not occur. However, recently, artificial leather itself has been made lighter (thinner film), and the thickness of the coating agent has been increased to maintain strength, and the amount of silicone has been increased to improve abrasion resistance. At that time, there is a problem that the appearance is whitened.

JP-A 2003-082227 (Patent Document 7) and JP-A 2004-107526 (Patent Document 8) disclose polyamide compositions containing a silicone resin. In addition, JP-A 2001-261919 (Patent Document 9) discloses that a slidability modifier in which a silicone-based oil or an olefin-based oil is mixed with a composite rubber-based graft copolymer in which at least one vinyl polymer is graft-polymerized to a composite rubber composed of an organopolysiloxane rubber component and a polyalkyl (meth)acrylate component is blended to in a thermoplastic resin or a thermoplastic elastomer. However, this technique has room for improvement in that compatibility is poor, interfacial peeling is likely to occur, and molding is difficult since silicone-based oil or olefin-based oil is blended.

In addition, JP-A 2015-224252 (Patent Document 10) proposes a technique aimed at reducing friction coefficient and improving abrasion resistance by mixing silicone oil with a silicone acrylic graft copolymer. However, in this technology, the silicone oil added to the silicone acrylic graft copolymer has a composition of only dimethylsiloxane and is difficult to mix with the resin. As a result, a lot of bleed occurs on the surface, but rather a tackiness appears, and the reduction of the friction coefficient and the improvement of the abrasion resistance cannot be sufficiently achieved. Thus, when the above additive components are kneaded into various resins, the transparency of the resin molded product is greatly hindered.

CITATION LIST

Patent Document 1: JP-A 2007-138326Patent Document 2: JP-A 2007-314919Patent Document 3: JP-A 2002-363403Patent Document 4: JP-A 2010-241963Patent Document 5: JP-A 2008-308785Patent Document 6: JP-A 2016-138242Patent Document 7: JP-A 2003-082227Patent Document 8: JP-A 2004-107526Patent Document 9: JP-A 2001-261919Patent Document 10: JP-A 2015-224252

SUMMARY OF THE INVENTION

The present invention has been made in view of the above circumstances, and it is therefore an object of the present invention to provide a thermoplastic urethane resin molded product made of a thermoplastic urethane resin composition containing a silicone acrylic graft copolymer resin having abrasion resistance and antifouling property and having a whitening prevention function.

As a result of intensive studies to achieve the above object, the present inventor has particularly found that a resin molded product obtained by blending a thermoplastic urethane resin and a silicone acrylic graft copolymer resin having dimethyldiphenylsiloxane and injection molding or extrusion molding these resin compositions has abrasion resistance and mold releasability, and can maintain transparency well. It has been found out that this resin molded product is a resin molded product consisting of a urethane resin composition that having improved compatibility, reduced interfacial peeling, and tribological properties such as abrasion resistance, compared to when silicone oil is mixed with silicone acrylic graft copolymer resin, and has completed the present invention.

Therefore, the present invention provides the following thermoplastic urethane resin molded product.

1. A resin molded product comprising:

(I) a thermoplastic urethane resin: 80 to 99.9% by weight; and

(II) a silicone acrylic graft copolymer resin: 0.1 to 20% by weight, the silicone acrylic graft copolymer resin comprising:

(A) an organopolysiloxane represented by the following general formula (1):


wherein R1is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, R2is an alkenyl group having 2 to 6 carbon atoms or an alkyl group having 1 to 6 carbon atoms in which a part of hydrogen atoms bonded to the carbon atoms is substituted with a mercapto group, vinyl group, acryloxy group or methacryloxy group, independently of each other, R3is a phenyl group, X is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, alkoxy group having 1 to 20 carbon atoms, or hydroxyl group, independently of each other, Y is a group defined by X or a group represented by —[O—Si(X)2]d—X, independently of each other, at least two of the groups represented by X and Y are hydroxyl groups, Z is an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms or a hydroxyl group, independently of each other, a is a number of 0 or more, b is a positive number that is 11.0 to 91.5% per total number of a to f, c is a positive number that is 0.0001 to 5% per total number of a to f, e is a number with a ratio of 8.5 to 60.0% with respect to the total number of a to f, f is a positive number of 0 to 24.0%1per total number of a to f, and d is a positive number of from 0 to 10; and

(B) an acrylic ester unit or a methacrylic ester unit, wherein a weight ratio of these components is (A):(B)=50:50 to 90:10.

2. The resin molded product according to 1 above, wherein the resin molded product is an injection molded product or an extrusion molded product.

3. The resin molded product according to 1 above, wherein an amount (e) of diphenylsiloxane in the organopolysiloxane represented by the general formula (1) is from 8.5 to 60.0% by weight or less.

4. The resin molded product according to 1 above, wherein the organopolysiloxane represented by the general formula (1) has a weight average molecular weight of from 1,000 to 200,000.

5. The resin molded product according to 1 above, wherein the silicone acrylic graft copolymer resin composition as the component (II) is an emulsion graft copolymer comprising,

(i) 100 parts by weight of the organopolysiloxane represented by the general formula (1),

(ii) 10 to 100 parts by weight of an acrylic ester monomer or a methacrylic ester monomer, and

(iii) 0.01 to 20 parts by weight of a functional group-containing monomer copolymerizable therewith, if necessary.

6. The resin molded product according to 1 above, wherein the thermoplastic urethane resin as the component (1) is a polyester-based, polyether-based or polycarbonate-based urethane resin.

7. The resin molded product according to 1 above, wherein the resin molded product with a thickness of 2 mm or the resin molded product with a thickness of 200 μm has a haze value of 85% or less.

Advantageous Effects of the Invention

The resin molded product of the present invention is a molded product having excellent abrasion resistance and antifouling properties, preventing whitening and having a good light transmission function. Furthermore, since the resin molded product of the present invention is obtained by kneading the additive component of the silicone acrylic graft copolymer into an urethane resin, there are great advantages in terms of work and environment in the production thereof.

