Resin composition and molded article thereof

Abstract

To provide a resin composition excellent in scratch resistance, impact resistance and product processability.SOLUTION: A resin composition contains a graft copolymer (A) containing a silicone component, a thermoplastic resin (B), and a fatty acid compound (C). The graft copolymer (A) is obtained by graft-polymerizing a monomer containing a (meth)acrylic acid ester compound onto a composite rubber (c) containing a polyorganosiloxane (a) and an alkyl acrylate rubber (b). A molded article containing the resin composition is also provided.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin composition and a molded article thereof. [Background technology]

[0002] Thermoplastic resins are easy to mold and process, and are widely used in many applications, including materials for residential facilities such as bathroom vanities, bathtubs, and flush toilets; outdoor building materials such as signs, window frames, and exterior wall materials; and vehicle components such as interior and exterior materials for vehicles. When used in the above applications, thermoplastic resins are required to have excellent impact resistance because the products may be damaged by contact with people or objects such as flying debris. Furthermore, thermoplastic resins are required to have excellent scratch resistance because the products may be scratched by contact with people or objects. Furthermore, thermoplastic resins are required to have excellent product processability while maintaining high impact resistance and scratch resistance.

[0003] As a method for improving the impact resistance of thermoplastic resins, for example, Patent Documents 1 and 2 disclose a methacrylic resin composition containing a polyorganosiloxane / acrylate ester composite rubber graft copolymer. Patent Document 3 discloses a methacrylic resin composition containing a graft copolymer containing a copolymer rubber polymer composed of an acrylate alkyl ester and a conjugated diene. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-100484 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-327880 [Patent Document 3] Special Publication No. 7-25973 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the resin compositions described in Patent Documents 1 and 2 do not provide sufficient scratch resistance in the resulting molded articles. The resin composition described in Patent Document 3 provides molded articles that are insufficient in terms of product processability and scratch resistance. Furthermore, the impact resistance is also insufficient. The present invention aims to solve these problems. That is, the present invention aims to provide a resin composition that provides molded articles that are excellent in scratch resistance, impact resistance, and product processability, and a molded article made from the resin composition. [Means for solving the problem]

[0006] The present invention has the following configuration. A first gist of the present invention is a resin composition containing a graft copolymer (A) containing a silicone component, a thermoplastic resin (B), and a fatty acid compound (C). A second gist of the present invention is a molded article containing the resin composition. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a resin composition having excellent scratch resistance, impact resistance, and processability, and a molded article thereof. Such a resin composition is suitable for use as a vehicle exterior material, and as a building material to be installed outdoors, such as a signboard, a window frame, or an exterior wall material. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a schematic diagram illustrating an outline of a scratch resistance test used to evaluate the resin molded article of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention will be described in detail below. In the present invention, "(meth)acrylate" and "(meth)acrylic acid" mean at least one selected from "acrylate" and "methacrylate" and at least one selected from "acrylic acid" and "methacrylic acid", respectively. Furthermore, in the present invention, "monomer" means an unpolymerized compound, and "repeating unit" means a unit derived from a monomer formed by polymerization of the monomer. The repeating unit may be a unit formed directly by a polymerization reaction, or may be a unit in which a portion of the unit is converted into a different structure by treating the polymer. Furthermore, "% by mass" indicates the content ratio of a specified component contained in a total amount of 100% by mass.

[0010] <Resin composition> The resin composition of the present invention is a resin composition containing a graft copolymer (A) containing a silicone-based component (hereinafter simply referred to as "graft copolymer (A)") described below, a thermoplastic resin (B) described below, and a fatty acid compound (C) described below.

[0011] The lower limit of the content of the graft copolymer (A) contained in the resin composition of the present invention is preferably 1% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more, relative to the total mass (100% by mass) of the resin composition, from the viewpoint of excellent impact resistance of the resulting molded article. On the other hand, the upper limit of the content of the graft copolymer (A) contained in the resin composition is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less, relative to the total mass (100% by mass) of the resin composition, from the viewpoint of ensuring that the resulting molded article does not impair the inherent performance of the thermoplastic resin. The above preferred upper and lower limits can be arbitrarily combined. For example, the content of the graft copolymer (A) contained in the resin composition is preferably 1% by mass or more and 50% by mass or less, more preferably 10% by mass or more and 45% by mass or less, and even more preferably 20% by mass or more and 40% by mass or less, relative to the total mass (100% by mass) of the resin composition.

[0012] The lower limit of the content of the thermoplastic resin (B) contained in the resin composition of the present invention is preferably 50% by mass or more, more preferably 55% by mass or more, and even more preferably 60% by mass or more, relative to the total mass (100% by mass) of the resin composition, from the viewpoint of ensuring that the resulting molded article does not impair the inherent performance of the thermoplastic resin. On the other hand, the upper limit of the content of the thermoplastic resin (B) contained in the resin composition is preferably 99% by mass or less, more preferably 90% by mass or less, and even more preferably 80% by mass or less, relative to the total mass (100% by mass) of the resin composition, from the viewpoint of ensuring excellent impact resistance of the resulting molded article. The above preferred upper and lower limits can be arbitrarily combined. For example, the content of the thermoplastic resin (B) contained in the resin composition is preferably 50% by mass or more and 99% by mass or less, more preferably 55% by mass or more and 90% by mass or less, and even more preferably 60% by mass or more and 80% by mass or less, relative to the total mass (100% by mass) of the resin composition.

[0013] The lower limit of the content of the fatty acid compound (C) contained in the resin composition of the present invention is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and even more preferably 1.0% by mass or more, relative to the total mass (100% by mass) of the resin composition, from the viewpoint of achieving excellent scratch resistance, product processability, and impact resistance in the resulting molded article. On the other hand, the upper limit of the content of the fatty acid compound (C) contained in the resin composition is preferably 10% by mass or less, more preferably 6.0% by mass or less, relative to the total mass (100% by mass) of the resin composition, from the viewpoint of maintaining good product processability and impact resistance in the resulting molded article and not impairing the inherent performance of the thermoplastic resin (B). It may also be 3.0% by mass or less. The above preferred upper and lower limits can be arbitrarily combined. For example, the content of the fatty acid compound (C) contained in the resin composition is preferably 0.01% by mass or more and 10% by mass or less, more preferably 0.1% by mass or more and 6.0% by mass or less, relative to the total mass (100% by mass) of the resin composition. It may be 1.0 mass % or more and 3.0 mass % or less.

[0014] The resin composition of the present invention may further contain other thermoplastic resins, such as styrene-based resins such as polystyrene (GPPS), high impact polystyrene (HIPS), ABS, SAN, AS, and MS resins, polyphenylene ether-based resins, polycarbonate-based resins, polyester-based resins, polyacetal resins, polyvinyl chloride-based resins, and polyolefin-based resins such as polyethylene and polypropylene, within the range that does not impair the effects of the present invention.

[0015] The content of the other thermoplastic resin that can be contained in the resin composition of the present invention is 10% by mass or less, preferably 5% by mass or less, based on 100% by mass of the total mass of the resin composition. Alternatively, the resin composition of the present invention may not contain the other thermoplastic resin.

[0016] The lower limit of the gel content of the resin composition of the present invention is not particularly limited, but is preferably 1% by mass or more from the viewpoint of excellent impact resistance of the resulting molded article. It is more preferably 5% by mass or more, and even more preferably 10% by mass or more. On the other hand, the upper limit of the gel content of the resin composition is preferably 35% by mass or less from the viewpoint of excellent product processability of the resulting molded article. It is more preferably 30% by mass or less, and even more preferably 25% by mass or less. The above preferred upper and lower limits can be arbitrarily combined. For example, the gel content of the resin composition of the present invention is preferably 1% by mass or more and 35% by mass or less, more preferably 5% by mass or more and 30% by mass or less, and even more preferably 10% by mass or more and 25% by mass or less. A specific method for measuring the gel content of a resin composition will be described later.

[0017] The lower limit of the tensile elongation of the resin composition of the present invention is preferably 20% or more, more preferably 25% or more. The tensile elongation serves as an index of product processability when producing molded articles containing the resin composition of the present invention or when applying the composition to various applications; the higher the tensile elongation, the better the product processability. While there are no particular limitations on the upper limit of the tensile elongation, a value of 60% or less can reduce residual stress in the resulting molded article and also makes it less likely for sagging or wrinkles to occur in the product during transport or harvesting during the production process. Methods for achieving a tensile elongation of 20% or more include, but are not limited to, the resin composition may be formulated to contain the preferred types, combinations, and amounts described above. A specific method for measuring the tensile elongation of the resin will be described later.

[0018] <Graft copolymer (A)> The graft copolymer (A) is one of the components of the resin composition of the present invention. The graft copolymer (A) is obtained by graft polymerizing a monomer containing a (meth)acrylic acid ester compound (described later) onto a composite rubber (c) made of a polyorganosiloxane (a) and an alkyl acrylate rubber (b) (described later).

[0019] The graft copolymer (A) can be a graft copolymer obtained by graft polymerizing 30 to 70 parts by mass of a monomer containing a (meth)acrylic acid ester compound with 30 to 70 parts by mass of a composite rubber (c) based on 100 parts by mass of the graft copolymer (A). When the content of the composite rubber (c) is 30 parts by mass or more, the impact resistance of the molded article is improved. The lower limit of the content of the composite rubber (c) is more preferably 35 parts by mass or more, and even more preferably 40 parts by mass or more. Furthermore, when the content of the composite rubber (c) is 70 parts by mass or less, the color development and appearance of the molded article are improved. The upper limit of the content of the composite rubber (c) is more preferably 65 parts by mass or less, and even more preferably 60 parts by mass or less. The monomer containing a (meth)acrylic acid ester compound to be grafted to the composite rubber (c) can be 30 to 70 parts by mass based on 100 parts by mass of the graft copolymer (A). When the amount of the monomer containing a (meth)acrylic acid ester compound is 30 parts by mass or more, the color development and appearance are good. When the amount of the monomer containing a (meth)acrylic acid ester compound is 70 parts by mass or less, the impact resistance of the molded article is good. The lower limit of the amount of the monomer containing a (meth)acrylic acid ester compound used is more preferably 35 parts by mass or more, and even more preferably 40 parts by mass or more. The upper limit of the amount of the monomer containing a (meth)acrylic acid ester compound used is more preferably 65 parts by mass or less, and even more preferably 60 parts by mass or less.

[0020] <Composite rubber (c)> The composite rubber (c) is one of the components of the resin composition of the present invention. The composite rubber (c) is a composite rubber containing a polyorganosiloxane (a) and an alkyl acrylate rubber (b). More specifically, the composite rubber (c) is a polymer obtained by polymerizing the polyorganosiloxane (a) with a monomer mixture containing an acrylic acid ester-based monomer (hereinafter referred to as the "acrylic acid ester-based monomer mixture"). As the polyorganosiloxane, polydimethylsiloxane is preferred from the viewpoint of improving the impact resistance of the molded article. It may also contain a vinyl-polymerizable functional group-containing siloxane or a siloxane-based crosslinking agent having three or more siloxane bonds. The proportion of the polyorganosiloxane relative to the total mass (100% by mass) of the polyorganosiloxane and the acrylic acid ester-based monomer mixture can be 1% by mass or more and 20% by mass or less. When the proportion of the polyorganosiloxane is 1% by mass or more, the impact resistance of the molded article is improved. Furthermore, if the proportion of polyorganosiloxane is 20% by mass or less, the color development and appearance of the molded article can be maintained good. The lower limit of the proportion of polyorganosiloxane is more preferably 2% by mass or more, and even more preferably 5% by mass or more. The upper limit of the proportion of polyorganosiloxane is more preferably 15% by mass or less.

[0021] Examples of the acrylic acid ester monomer include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate. In order to improve the impact resistance of the resulting molded article, n-butyl acrylate is particularly preferred. The acrylic acid ester monomer mixture preferably contains 80% by mass or more of the acrylic acid ester monomer relative to 100% by mass of the total acrylic acid ester monomer mixture. Having 80% by mass or more of the acrylic acid ester monomer results in improved color development and appearance of the molded article. The lower limit of the acrylic acid ester monomer is more preferably 85% by mass or more, and even more preferably 90% by mass or more. The acrylic acid ester monomer mixture may contain 20% by mass or less of another vinyl monomer copolymerizable with the acrylic acid ester monomer relative to 100% by mass of the total monomer mixture. Having 20% by mass or less of the other vinyl monomer results in improved color development and appearance of the molded article. The lower limit of the other vinyl monomer is more preferably 15% by mass or less, and even more preferably 10% by mass or more.

[0022] The proportion of the acrylic acid ester-based monomer mixture relative to 100% by mass of the total mass of the polyorganosiloxane and the acrylic acid ester-based monomer mixture can be 80% by mass or more and 99% by mass or less relative to 100% by mass of the total mass of the composite rubber (c). When the proportion of the acrylic acid ester-based monomer mixture is 80% by mass or more, the color development and appearance of the molded article are good. When the proportion of the acrylic acid ester-based monomer mixture is 99% by mass or less, the impact resistance of the molded article can be maintained well. The lower limit of the proportion of the acrylic acid ester-based monomer mixture is more preferably 85% by mass or more. The upper limit of the proportion of the acrylic acid ester-based monomer mixture is more preferably 98% by mass or less, and even more preferably 95% by mass or less.

[0023] The mass average particle diameter of the composite rubber (c) is preferably 0.07 μm or more and 0.15 μm or less. If the mass average particle diameter of the composite rubber (c) is 0.07 μm or more, the impact resistance of the molded article will be good. If the mass average particle diameter of the composite rubber (c) is 0.15 μm or less, the color development and appearance of the molded article will be good. Furthermore, the lower limit of the mass average particle diameter of the composite rubber (c) is more preferably 0.09 μm or more, and the upper limit is more preferably 0.13 μm or less. The mass average particle diameter can be adjusted by a known method.

[0024] As the monomer containing a (meth)acrylic acid ester compound to be grafted to the composite rubber (c), methacrylic acid esters, acrylic acid esters, etc. are preferred. Examples of methacrylic acid esters include methyl methacrylate, ethyl methacrylate, 2-ethylhexyl methacrylate, etc. Examples of acrylic acid esters include methyl acrylate, ethyl acrylate, n-butyl acrylate, etc. Among these, a mixture of a methacrylic acid ester and an acrylic acid ester is preferred because of its excellent weather resistance, color development, appearance, and thermal stability, and a mixture of methyl methacrylate and methyl acrylate, or a mixture of methyl methacrylate and ethyl acrylate is particularly preferred.

[0025] The monomer containing a (meth)acrylic acid ester compound to be grafted to the composite rubber (c) preferably contains 80 mass% or more of the (meth)acrylic acid ester compound relative to 100 mass% of the total mass of the monomers. If the (meth)acrylic acid ester compound is 80 mass% or more, weather resistance, color development, appearance, and thermal stability are improved. It is more preferable that the monomer containing a (meth)acrylic acid ester compound contains 80 mass% or more of the methacrylic acid ester.

[0026] The monomer containing the (meth)acrylic ester compound to be grafted onto the composite rubber (c) can contain other vinyl monomers copolymerizable with the (meth)acrylic ester compound. Examples of other vinyl monomers copolymerizable with the (meth)acrylic ester compound include aromatic vinyl monomers such as styrene and α-methylstyrene, vinyl cyanide monomers such as acrylonitrile and methacrylonitrile, and cyclic vinyl monomers such as maleic anhydride and N-substituted maleimide. The amount of other vinyl monomers copolymerizable with the (meth)acrylic ester compound is preferably 20% by mass or less based on 100% by mass of the total monomer mass. If the amount of other vinyl monomers is 20% by mass or less, the weather resistance, color development, appearance, and thermal stability of the resulting molded product will be good.

[0027] The graft copolymer (A) can be produced by known polymerization methods, among which emulsion polymerization is particularly preferred because it is easy to control the particle size and the core / shell structure.

[0028] The lower limit of the gel content of the graft copolymer (A) is not particularly limited, but is preferably 40% by mass or more from the viewpoint of excellent impact resistance of the resulting molded article. It is more preferably 50% by mass or more, and even more preferably 55% by mass or more. On the other hand, the upper limit of the gel content of the graft copolymer (A) is 99% by mass or less from the viewpoint of excellent product processability of the resulting molded article. It is more preferably 95% by mass or less, and even more preferably 90% by mass or less. The above preferred upper and lower limits can be arbitrarily combined. For example, the gel content of the graft copolymer (A) of the present invention is preferably 40% by mass or more and 99% by mass or less, more preferably 50% by mass or more and 95% by mass or less, and even more preferably 55% by mass or more and 90% by mass or less.

[0029] Here, the gel content of the graft copolymer (A) can be calculated according to the following formula. G' = (m' / M') x 100 In the formula, G' (%) represents the gel content of the graft copolymer (A), M' represents the mass of a predetermined amount of the graft copolymer (A) (also referred to as the mass before extraction), and m' represents the mass of the acetone-insoluble portion of the predetermined amount of the graft copolymer (A) (also referred to as the mass after extraction). Since the gel content of the resin composition is 35% by mass or less, when the gel content of the graft copolymer (A) is 80% by mass or more, the gel content of the resin composition can be adjusted by further adding a thermoplastic resin (B). The ratio of the contents of the graft copolymer (A) and the thermoplastic resin (B) in the resin composition can be appropriately set so that the gel content of the resin composition is the desired value.

[0030] <Thermoplastic resin (B)> Thermoplastic resin (B) is one of the components of the resin composition of the present invention. Examples of thermoplastic resin (B) include olefin-based resins such as polypropylene and polyethylene; styrene-based resins such as polystyrene, (meth)acrylate-styrene copolymers, styrene-acrylonitrile copolymers, and styrene-maleic anhydride copolymers; acrylic resins such as polymethyl methacrylate; polycarbonate-based resins; polyamide resins; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polylactic acid; engineering plastics such as (modified) polyphenylene ether resins, polyoxymethylene resins, polysulfone resins, polyarylate resins, and polyphenylene resins; and vinyl chloride-based resins such as rigid vinyl chloride resins, semi-rigid vinyl chloride resins, and flexible vinyl chloride resins. These thermoplastic resins (B) can be used alone or in combination. Among these, acrylic resins are preferred because the resulting molded articles have excellent weather resistance, color development, and appearance. Specifically, the acrylic resin is preferably a (meth)acrylic acid ester polymer containing a repeating unit derived from a (meth)acrylic acid ester monomer. When the thermoplastic resin (B) contains a (meth)acrylic acid ester polymer, the resulting molded article has good weather resistance, color development, and appearance. Specifically, the (meth)acrylic acid ester polymer is preferably a polymer containing 80 mass% or more of a repeating unit derived from a (meth)acrylic acid ester monomer, relative to 100 mass% of the total mass of the (meth)acrylic acid ester polymer. Specifically, the (meth)acrylic acid ester polymer is more preferably a copolymer containing a repeating unit derived from a methacrylic acid ester and a repeating unit derived from an acrylic acid ester. The methacrylic acid ester and the acrylic acid ester may be the same as those used in the graft copolymer (A), and a copolymer of methyl methacrylate and methyl acrylate is particularly preferred. The (meth)acrylic acid ester polymer may also contain components other than the methacrylic acid ester and the acrylic acid ester, as necessary.Other components include aromatic vinyl monomers such as styrene and α-methylstyrene, vinyl cyanide monomers such as acrylonitrile and methacrylonitrile, and cyclic vinyl monomers such as maleic anhydride and N-substituted maleimides. By using these other components, it is possible to improve the desired properties of the resulting molded product, such as moldability, appearance, color development, impact strength, and heat resistance.

[0031] The thermoplastic resin (B) preferably contains 80% by mass or more of a (meth)acrylic acid ester-based monomer component. If the content of the (meth)acrylic acid ester-based monomer component is 80% by mass or more, the weather resistance, color development, appearance, etc. of the obtained molded article will be good. The content of the (meth)acrylic acid ester-based monomer component is more preferably 90% by mass or more, and even more preferably 95% by mass or more.

[0032] <Fatty acid compound (C)> The fatty acid compound (C) is one of the components of the resin composition of the present invention. The resin composition of the present invention is characterized by using the fatty acid compound (C) in combination with a graft copolymer (A) containing a silicone-based component. While it has been known that the fatty acid compound (C) improves the scratch resistance of resin molded articles, its effect of improving the impact resistance of resin molded articles has not been known. However, in the present invention, it has been found that when the fatty acid compound (C) is used in combination with a graft copolymer (A) containing a silicone-based component, the impact resistance of the resulting molded article is superior to that when the fatty acid compound (C) is used in combination with a graft copolymer (A) containing a silicone-based component, compared to when the fatty acid compound (C) is used in combination with a graft copolymer not containing a silicone-based component. Furthermore, it has also been found that the resulting molded article has superior product processability or scratch resistance.

[0033] As the fatty acid compound (C), a chain hydrocarbon compound having at least one carbonyl group or carboxyl group in the molecule is preferred, from the viewpoint of easily imparting excellent scratch resistance to the resulting molded article. A chain hydrocarbon compound having at least one carbonyl group or carboxyl group in the molecule means a compound in which the carbon atom to which the carbonyl group or carboxyl group is bonded is a constituent atom of the carbon chain. The carbon chain in the chain hydrocarbon compound having at least one carbonyl group or carboxyl group in the molecule may be saturated or unsaturated, and may be linear or branched.

[0034] Examples of such fatty acid compounds (C) include fatty acids and their derivatives as chain hydrocarbon compounds having a carboxyl group in the molecule, fatty acid amides and their derivatives as chain hydrocarbon compounds having an amide group in the molecule, and fatty acid alkyl esters and their derivatives, or fatty acid glycerides and their derivatives as chain hydrocarbon compounds having an ester group or a carbonyl group in the molecule.

[0035] Fatty acid derivatives, fatty acid amide derivatives, fatty acid alkyl ester derivatives, and fatty acid glyceride derivatives are compounds in which hydrogen atoms in chain hydrocarbon compounds or part or all of the side chains are replaced with other organic groups. Examples of the organic group include polyether groups, polyalkyl groups, aralkyl groups, and polyester groups, which may be used alone or in combination of two or more. Furthermore, fatty acid amide derivatives can be appropriately selected from various compounds such as monoamides and bisamides depending on the situation.

[0036] These fatty acid compounds (C) may be used alone or in combination of two or more.

[0037] The lower limit of the melting point of the fatty acid compound (C) is not particularly limited, but is preferably 90°C or higher from the viewpoint of improving the scratch resistance of the resulting molded article. Although the reason for this is unclear, it is presumed that if the melting point is 90°C or higher, the fatty acid compound (C) contained in the methacrylic resin composition tends to volatilize in the mold during injection molding, adhere to the mold surface, liquefy, and condense. This prevents a decrease in the amount of fatty acid compound (C) discharged as a gas from the gas vent, and as a result, a high content of fatty acid compound (C) tends to be present on or near the surface of the resulting molded article. The melting point of the fatty acid compound (C) is more preferably 95°C or higher, and even more preferably 100°C or higher. On the other hand, the upper limit of the melting point of the fatty acid compound (C) is not particularly limited, but is preferably 150°C or lower from the viewpoint of improving the scratch resistance of the resulting molded article. Although the reason for this is unclear, it is believed that if the melting point of the fatty acid compound (C) is 150°C or lower, the fatty acid compound (C) contained in the methacrylic resin composition volatilizes sufficiently in the mold during injection molding, making it easier to achieve the above-mentioned functions and effects. The melting point of the fatty acid compound (C) is more preferably 130°C or lower, and even more preferably 120°C or lower. The upper and lower limits of the melting point of the fatty acid compound (C) can be arbitrarily combined. For example, the melting point of the fatty acid compound (C) is preferably 90°C or higher and 150°C or lower, more preferably 95°C or higher and 130°C or lower, and even more preferably 100°C or higher and 120°C or lower.

[0038] The upper limit of the 10% weight loss temperature of the fatty acid compound (C) is not particularly limited, but is preferably 350°C or lower from the viewpoint of improving the scratch resistance of the resulting molded article. Although the reason for this is unclear, it is presumed that the lower the 10% weight loss temperature of the fatty acid compound (C) contained in the methacrylic resin composition, the more easily the fatty acid contained in the methacrylic resin composition volatilizes in the mold during injection molding. As a result, the fatty acid compound (C) that adheres to the mold surface and liquefies or condenses diffuses and migrates into the methacrylic resin composition injected into the mold later, resulting in a high content of the fatty acid compound (C) on and near the surface of the final molded article. The 10% weight loss temperature of the fatty acid compound (C) is more preferably 300°C or lower, and even more preferably 260°C or lower. On the other hand, the lower limit of the 10% weight loss temperature of the fatty acid compound (C) is not particularly limited, but is preferably 190°C or higher from the viewpoint of improving the scratch resistance of the resulting molded article. Although the reason for this is unclear, it is presumed that if the 10% weight loss temperature is 190°C or higher, the fatty acid compound (C) will not thermally decompose during injection molding, allowing the fatty acid compound (C) to fully exert its effects. The 10% weight loss temperature of the fatty acid compound (C) is more preferably 200°C or higher, and even more preferably 210°C or higher. The upper and lower limits of the 10% weight loss temperature of the fatty acid compound (C) can be arbitrarily combined. For example, the 10% weight loss temperature of the fatty acid compound (C) is preferably 190°C or higher but 350°C or lower, more preferably 200°C or higher but 300°C or lower, and even more preferably 210°C or higher but 260°C or lower.

[0039] Among these fatty acid compounds (C), fatty acid amide compounds and derivatives thereof (hereinafter, these may be collectively referred to as "fatty acid amide compounds (D1)") are preferred.

[0040] As the fatty acid amide compound (D1), a compound represented by the following general formula (i) (hereinafter also referred to as "compound (i)") can be used. Compound (i) is preferred from the viewpoint that even when compounded in a small amount, the resulting molded article has excellent scratch resistance and is unlikely to impair the inherent performance of the thermoplastic resin. R-CONH2(i) (In general formula (i), R is a hydrocarbon group having 10 to 25 carbon atoms which may have a substituent.)

[0041] The lower limit of the number of carbon atoms in R in formula (i) of the fatty acid amide compound (D1) is preferably 10 or more, more preferably 15 or more, and even more preferably 17 or more, from the viewpoints of excellent compatibility with the (meth)acrylic polymer (A) and excellent scratch resistance of the resulting molded article. The upper limit of the number of carbon atoms in R in formula (i) of the fatty acid amide compound (D1) is preferably 25 or less, more preferably 24 or less, and even more preferably 23 or less, from the viewpoints of improving the dispersibility of the fatty acid compound (C) in the methacrylic resin composition and maintaining good scratch resistance of the resulting molded article. The above preferred upper and lower limits can be arbitrarily combined. For example, the number of carbon atoms in R in formula (i) of the fatty acid amide compound is preferably 10 to 25, more preferably 15 to 24, and more preferably 17 to 23.

[0042] Among the fatty acid compounds (C), the fatty acid amide compound (D1) is preferred because it has excellent compatibility with the (meth)acrylic polymer (A), the fluidity of the methacrylic resin composition, and the scratch resistance of the resulting molded article.

[0043] Examples of the fatty acid amide compound (D1) include saturated fatty acid amide compounds, unsaturated fatty acid amide compounds, bis-fatty acid amide compounds, and methylol fatty acid amide compounds. These fatty acid amide compounds may be used alone or in combination of two or more.

[0044] Examples of saturated fatty acid amide compounds include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide, and methylolstearic acid amide. These saturated fatty acid amide compounds may be used alone or in combination of two or more.

[0045] Examples of unsaturated fatty acid amides include erucic acid amide, oleic acid amide, brassidic acid amide, and elaidic acid amide. These unsaturated fatty acid amide compounds may be used alone or in combination of two or more. Among these unsaturated fatty acid amide compounds, erucic acid amide and oleic acid amide are preferred, and erucic acid amide is more preferred, because the resulting molded article has excellent scratch resistance.

[0046] Examples of bis-fatty acid amide compounds include bis-fatty acid amides such as methylene bis-stearic acid amide, methylene bis-oleic acid amide, ethylene bis-stearic acid amide, and ethylene bis-oleic acid amide; stearyl stearic acid amide, stearyl erucic acid amide, and oleyl palmitic acid amide. These bis-fatty acid amide compounds may be used alone or in combination of two or more.

[0047] Among the fatty acid amide compounds (D1) described above, saturated fatty acid amide compounds are preferred because the resulting molded article has better scratch resistance. It is more preferred that the saturated fatty acid amide compound contains either stearic acid amide or palmitic acid amide, and it is even more preferred that the saturated fatty acid amide compound contains stearic acid amide and palmitic acid amide as the main components, because the resulting molded article has even better scratch resistance. Here, "containing as the main components" means that the total mass of stearic acid amide and palmitic acid amide is 85.0% by mass or more relative to 100% by mass of the total mass of the fatty acid amide compound.

[0048] <Other additives> The resin composition of the present invention may contain other additives in addition to the graft copolymer (A) and the fatty acid compound (C). Examples of the other additives include pigments, stabilizers, reinforcing agents, fillers, flame retardants, foaming agents, lubricants, plasticizers, antistatic agents, etc. These other additives may be used alone or in combination of two or more.

[0049] <Method of manufacturing resin composition> The resin composition of the present invention can be prepared, for example, by mixing predetermined amounts of the graft copolymer (A), the thermoplastic resin (B), and the fatty acid compound (C), melt-kneading the mixture using a known melt-kneading means, and then obtaining the resulting melt-kneaded mixture in the form of pellets using a known cutting and crushing device such as a pelletizer. Known melt-kneading means that can be used include kneaders such as a single-screw extruder, a twin-screw extruder, a Banbury mixer, a pressure kneader, and a roll mill. Alternatively, the mixture can be used directly as a raw material for producing a molded product.

[0050] <Molded products> The molded article of the present invention can be obtained by molding the resin composition of the present invention. Examples of methods for obtaining the molded article include known molding methods such as injection molding, extrusion molding, pressure molding, blow molding, compression molding, calendar molding, and inflation molding. The obtained molded article may be further subjected to secondary molding using known molding methods such as pressure molding and vacuum molding. Molding conditions such as molding temperature and molding pressure can be appropriately set.

[0051] The resin composition and molded article of the present invention have excellent scratch resistance, impact resistance, and product processability, and therefore can be preferably used for a variety of molded articles, such as exterior and interior material parts for vehicles, building material parts such as wall materials and window frames, tableware, toys, home appliance parts, and interior materials. [Example]

[0052] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the following, "parts" and "%" represent "parts by mass" and "% by mass", respectively.

[0053] <Evaluation method> The evaluations in the examples and comparative examples were carried out by the following methods.

[0054] (1) Preparation of evaluation test specimens <Preparation of resin molded body X1> The resin compositions obtained in the examples and comparative examples were dried at 80°C for about 12 hours, and then injection-molded using an injection molding machine (model name: EC75SXIII-2A, manufactured by Toshiba Machine Co., Ltd.) at a molding temperature of 250°C and a mold temperature of 60°C to obtain test pieces (resin molded body X1) having a length of 80 mm, a width of 10 mm, and a thickness of 4 mm. <Preparation of resin molded body X2> The resin compositions obtained in the examples and comparative examples were dried at 80°C for about 12 hours, and then injection-molded using an injection molding machine (model name: EC75SXIII-2A, manufactured by Toshiba Machine Co., Ltd.) at a molding temperature of 210°C and a mold temperature of 40°C to obtain test pieces (resin molded body X2) having a length of 100 mm, a width of 100 mm, and a thickness of 3 mm. <Preparation of resin molded body X3> The resin compositions obtained in the examples and comparative examples were dried at 80°C for approximately 12 hours, and then injection-molded using an injection molding machine (model name: EC75SXIII-2A, manufactured by Toshiba Machine Co., Ltd.) at a molding temperature of 230°C and a mold temperature of 60°C to obtain dumbbell test pieces (resin molded body X3) measuring 150 mm in length, 10 mm in width, and 4 mm in thickness.

[0055] (2) Impact resistance evaluation As an index of impact resistance, the notched Charpy impact strength (kJ / m) of resin molded body X1 was measured using a digital impact tester (model name: DG-UB, manufactured by Toyo Seiki Seisakusho) in accordance with ISO 179-1 at a temperature of 23°C. 2 ) was measured. A Charpy impact strength of 8.0 or more was rated as "A," a Charpy impact strength of 3.0 or more but less than 8.0 was rated as "B," and a Charpy impact strength of less than 3.0 was rated as "C." The higher the Charpy impact strength, the better the impact resistance.

[0056] (3) Evaluation of product processability As an index of product processability, a tensile test was performed on the resin molded product X3 using a tensile tester (model name: Strograph TF, manufactured by Toyo Seiki Seisakusho, Ltd.) in accordance with JIS K6723 at a tensile speed of 50 mm / min to measure the tensile elongation (%). The higher the tensile elongation, the better the product processability of the resin composition. Prior to the measurement, the test specimen was annealed at a temperature of 50°C for 16 hours. A tensile elongation (%) of 25% or more was rated as "AA," a tensile elongation of 20% or more but less than 25% was rated as "A," a tensile elongation of 15% or more but less than 20% was rated as "B," and a tensile elongation of less than 15% was rated as "C."

[0057] (4) Evaluation of scratch resistance As an index of the color development property of the thermoplastic resin composition, the gloss of the test piece before and after the scratch resistance test was measured by the following method, and the difference (gloss difference) was calculated. The resin molded body X2 was placed on a platform, and a steel wool scratch tester (positioning actuator, model name: XY-FS0010-902, manufactured by NSK Ltd.) was used. Five layers of medical gauze (Chikyu Tonbo 100% cotton, manufactured by Yamato Kogyo Co., Ltd.) were stacked on a flat friction element (diameter 24 mm). As shown in Figure 1, the friction element was moved back and forth 200 times over a distance of 50 mm under a load of 500 g in the MD direction (flow direction during molding) from the injection molding gate position to the surface of the resin molded body X2, so that the center portion 3 of the resin molded body X2 passed through. A friction and wear treatment portion 1 was formed on the surface of the resin molded body X2. Next, for the test pieces before and after the scratch resistance test, a specular gloss meter (model name: MULTI GLOSS 268Plus, manufactured by KONICA MINOLTA CORPORATION) was used to measure the 60° gloss of the test pieces by irradiating a light beam parallel to the direction in which the friction element was moved back and forth onto the central portion 3 of the resin molded body X2 (for the test pieces subjected to the scratch resistance test, the central portion of the surface on which the friction and wear treatment portion 2 was formed) under the condition that the diameter of the incident light beam was 15 mm in accordance with JJIS Z 8741-1997, and the change in 60° gloss (gloss difference) before and after the scratch resistance test was calculated using the following formula (1): Gloss difference = gloss of test piece after scratch resistance test - gloss of test piece before scratch resistance test Formula (1) The scratch resistance was evaluated according to the following criteria. AA: The gloss difference is −1.5 or more. A: The gloss difference is -3.0 or more and less than -1.5. B: The gloss difference is −4.0 or more and less than −3.0. C: The gloss difference is less than −4.0.

[0058] (5) Gel content of the resin composition Resin compositions obtained in Examples and Comparative Examples Approximately 1.0 g was weighed to the last three digits using an electronic balance, and this was defined as the pre-extraction mass M (unit: g). Next, the resin composition was dissolved in 100 mL of acetone, and the resulting acetone solution was refluxed at 65°C for 4 hours. The extract from the refluxed acetone solution was centrifuged for 30 minutes at 4°C and 14,000 rpm using a high-speed refrigerated centrifuge (product name: CR21G, manufactured by Hitachi Koki Co., Ltd.). The extract after centrifugation was removed by decantation, and the acetone-insoluble solid was recovered. The recovered solid was refluxed and centrifuged again under the same conditions as above, and then the acetone-insoluble solid was recovered by decantation. The recovered solid was dried at 50°C for 24 hours, and the mass of the final acetone-insoluble solid obtained was weighed to the last three digits using an electronic balance, and this was defined as the post-extraction mass m (unit: g). Next, the gel content G (%) of the resin composition was calculated using the following formula. G = (m / M) × 100 (6) Mass average particle diameter The mass average particle diameter of the polymer latex was determined by measuring the absorbance at a wavelength of 700 nm using a UV-visible spectrophotometer (Shimadzu UV-mini1240) for a solution diluted with deionized water to a concentration (solid content) of 0.5 g / L, and calculating the mass average particle diameter using a conversion formula between absorbance and mass average particle diameter prepared in advance. The conversion formula was calculated using the absorbance and mass average particle diameter measured using a transmission electron microscope.

[0059] (material) Graft copolymer (A-1): A polyorganosiloxane / acrylic rubber graft copolymer prepared in Production Example 1, in which a vinyl monomer is graft polymerized onto a polyorganosiloxane / acrylic rubber. Graft copolymer (A-2): Metablen C-950 (trade name, manufactured by Mitsubishi Chemical Corporation, a core-shell type diene rubber graft copolymer obtained by graft polymerizing a vinyl monomer onto a diene rubber) Thermoplastic resin (B-1): ACRYPET VH 001 (trade name, manufactured by Mitsubishi Chemical Corporation, acrylic resin containing 95% or more by mass of repeating units derived from methyl methacrylate) Thermoplastic resin (B-2): ACRYPET VH5 (trade name, manufactured by Mitsubishi Chemical Corporation, acrylic resin containing 95% or more by mass of repeating units derived from methyl methacrylate) Fatty acid compound (C-1): fatty acid amide containing stearic acid amide as the main component (trade name: IncroMax (registered trademark) PS, manufactured by CRODA, 10% weight loss temperature: 246°C, melting point: 109°C) Fatty acid compound (C-2): ethylene bisoleamide (trade name: Slipax O, manufactured by Mitsubishi Chemical Corporation, 10% weight loss temperature: 344°C, melting point: 119°C) Fatty acid compound (C-3): fatty acid amide containing stearic acid amide as the main component (trade name: Fatty Acid Amide S, manufactured by Kao Corporation, 10% weight loss temperature: 243°C, melting point: 103°C)

[0060] [Production Example 1] (Production of Polyorganosiloxane Latex (L)) A mixture of 98 parts by mass of octamethylcyclotetrasiloxane, 2 parts by mass of γ-methacryloyloxypropyldimethoxymethylsilane, 0.67 parts by mass of sodium dodecylbenzenesulfonate, and 300 parts by mass of deionized water was stirred in a homomixer at 10,000 rpm for 2 minutes, and then transferred to a homogenizer at 300 kg / cm. 2 The mixture was passed through once at a pressure of 1000 kJ / min to obtain a premixed organosiloxane latex.

[0061] An aqueous solution of 10 parts by weight of dodecylbenzenesulfonic acid and 90 parts by weight of deionized water was added to a reactor equipped with a reflux condenser. The temperature of the liquid in the reactor was raised to 85°C while stirring, and the premixed organosiloxane latex was added dropwise over 4 hours. After the dropwise addition was completed, the mixture was held for another hour and then cooled to near room temperature. The reaction mixture in the reactor was then neutralized with an aqueous caustic soda solution to obtain a latex. The solids concentration of the resulting latex was 17.6% by weight, and the mass average particle size of the polyorganosiloxane in the latex was 0.05 μm.

[0062] (Production of Graft Copolymer (A)) 7 parts by weight (solids) of polyorganosiloxane latex (L), 0.2 parts by weight of sodium dodecylbenzenesulfonate, and 200 parts by weight of deionized water (including the water in polyorganosiloxane latex (L)) were added to a reactor equipped with a reflux condenser. Then, a mixture of 53 parts by weight of n-butyl acrylate, 0.6 parts by weight of allyl methacrylate, 0.2 parts by weight of 1,3-butylene glycol dimethacrylate, and 0.4 parts by weight of cumene hydroperoxide was added with stirring. After purging the reactor with nitrogen, the liquid temperature in the reactor was raised to 50°C. An aqueous solution consisting of 0.001 parts by weight of ferrous sulfate, 0.003 parts by weight of ethylenediaminetetraacetic acid disodium salt, 0.3 parts by weight of sodium formaldehyde sulfoxylate, and 2 parts by weight of deionized water was then added, and polymerization was carried out. Due to heat generation during polymerization, the liquid temperature in the reactor rose to 80°C, and this state was maintained for 1 hour. The mass average particle diameter of the resulting polyorganosiloxane / acrylate composite rubber was 0.10 μm. After the liquid temperature inside the reactor was raised to 70° C., a mixed liquid consisting of 36 parts by mass of methyl methacrylate, 4 parts by mass of methyl acrylate, and 0.2 parts by mass of cumene hydroperoxide was added dropwise over 3 hours to carry out polymerization.

[0063] After the dropwise addition of the mixed solution was completed, the mixture was maintained for another hour. The liquid temperature in the reactor was then cooled to near room temperature, and a latex of graft copolymer (A) was obtained by graft polymerizing methyl methacrylate and methyl acrylate onto a composite rubber composed of polyorganosiloxane and n-butyl acrylate rubber. The mass average particle diameter of the graft copolymer in the obtained latex was 0.13 μm.

[0064] 100 parts of an aqueous calcium acetate solution (3% by mass) was added to a separate reactor equipped with a reflux condenser, and the temperature was raised to 80°C while stirring. Next, 100 parts of the graft copolymer latex was gradually added dropwise to the calcium acetate, which solidified to obtain a precipitate. The resulting precipitate was then separated, washed, dehydrated, and dried to obtain graft copolymer (A-1).

[0065] Example 1 The graft copolymer (A-1), thermoplastic resin (B-1), and fatty acid compound (C-1) produced in Production Example 1 were mixed in the proportions shown in Table 1 and thoroughly mixed using a Henschel mixer. The mixture was then fed into a twin-screw extruder (model: PCM30, manufactured by Ikegai Corporation, φ30 mm, L / D=25) and kneaded at a barrel temperature of 230°C (set) and a screw rotation speed of 250 rpm to obtain a pelletized resin composition. The evaluation results of the resulting resin composition are shown in Table 1. In Table 1, the content ratios (unit: mass%) of the graft copolymer (A), thermoplastic resin (B), and fatty acid compound (C) in the resin composition are calculated based on the blend amounts (unit: parts by mass) of each component.

[0066] Examples 2 to 5, Comparative Examples 1 to 6 Pellet-shaped resin compositions were obtained in the same manner as in Example 1, except that the formulations were as shown in Table 1. Table 1 shows the evaluation results of the obtained resin compositions.

[0067] [Table 1]

[0068] The molded articles molded from the resin compositions obtained in the Examples were excellent in impact resistance, product processability, and scratch resistance. On the other hand, the molded article molded from the resin composition obtained in Comparative Example 1 was poor in mold processability and scratch resistance because it did not contain the fatty acid compound (C). The molded article molded from the resin composition obtained in Comparative Example 2 was poor in impact resistance and mold processability because it did not contain the graft copolymer (A). The molded articles molded from the resin compositions obtained in Comparative Examples 3 to 6 were poor in impact resistance because the graft copolymer did not contain a silicone-based component. In particular, the molded articles of Comparative Examples 3 to 5 were poor in scratch resistance. Furthermore, the molded articles of Comparative Examples 3 and 4 were also poor in mold processability. [Industrial Applicability]

[0069] The resin composition of the present invention provides molded articles having excellent scratch resistance, impact resistance, and product processability, and therefore can be suitably used as materials for housing facilities such as washbasins, bathtubs, and flush toilets; building materials for outdoor use such as signs, window frames, and exterior wall materials; and vehicle components such as interior and exterior materials for vehicles. [Explanation of symbols]

[0070] 1 Test piece 2 Friction and wear treatment part 3 Center part of test piece 4 Gate

Claims

1. A resin composition comprising a graft copolymer (A) containing a silicone-based component, a thermoplastic resin (B), and a fatty acid compound (C).

2. The graft copolymer (A) is a graft copolymer obtained by graft polymerizing a monomer containing a (meth)acrylic acid ester compound to a composite rubber (c) containing polyorganosiloxane (a) and an alkyl acrylate rubber (b). The resin composition according to claim 1.

3. The resin composition according to claim 1 or 2, wherein the fatty acid compound (C) has a melting point of 90°C or higher.

4. The resin composition according to any one of claims 1 to 3, wherein the fatty acid compound (C) has a 10% weight loss temperature of 350°C or lower.

5. The resin composition according to any one of claims 1 to 4, wherein the fatty acid compound (C) contains a fatty acid amide as a main component.

6. The resin composition according to claim 5 , wherein the fatty acid amide is represented by the following general formula (i): R-CONH ２ (i) (In the formula, R is a hydrocarbon group having 10 to 25 carbon atoms which may have a substituent.)

7. The resin composition according to any one of claims 1 to 6, wherein the thermoplastic resin (B) comprises a (meth)acrylic acid ester-based polymer containing a repeating unit derived from a (meth)acrylic acid ester-based monomer.

8. The resin composition according to claim 7, wherein the (meth)acrylic acid ester-based polymer contains 80 mass% or more of repeating units derived from (meth)acrylic acid ester-based monomers, relative to 100 mass% of the total mass of the (meth)acrylic acid ester-based polymer.

9. The graft copolymer (A) is a graft copolymer obtained by graft polymerizing 30 to 70 parts by mass of a monomer containing a (meth)acrylic acid ester compound to 30 to 70 parts by mass of a composite rubber (c) containing 1 to 20% by mass of polyorganosiloxane (a) and 80 to 99% by mass of alkyl acrylate rubber (b). The resin composition according to any one of claims 1 to 8.

10. The resin composition according to any one of claims 1 to 9, wherein the gel content of the resin composition is 1% by mass or more.

11. The resin composition according to claim 10, wherein the resin composition has a gel content of 35 mass% or less.

12. The resin composition contains 1% by mass or more and 50% by mass or less of the graft copolymer (A) and 50% by mass or more and 99% by mass or less of the thermoplastic resin (B), relative to 100% by mass of the total mass of the resin composition. The resin composition according to any one of claims 1 to 11.

13. The resin composition contains a fatty acid compound (C) in an amount of 0.01% by mass or more and 10% by mass or less, relative to 100% by mass of the total mass of the resin composition. The resin composition according to any one of claims 1 to 12.

14. A molded article comprising the resin composition according to any one of claims 1 to 13.

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