Styrenic resin composition and molded article

Abstract

To provide a styrenic resin composition which is used in a molded body excellent in weather resistance, mechanical strength and oil resistance without lowering heat resistance and transparency.SOLUTION: A styrenic resin composition contains 10 mass% or more and 100 mass% or less of a styrene-unsaturated carboxylic acid-based resin (A) having a styrenic monomer unit (1) and an unsaturated carboxylic acid-based monomer unit (a1), and 0 mass% or more and 90 mass% or less of a (meth)acrylic resin (B) having an unsaturated carboxylic acid-based monomer unit (b1), wherein the styrenic resin composition contains 0-2.0 mass% of a light stabilizer (C) and 0.001-2.0 mass% of an ultraviolet absorber (D) with respect to the total amount (100 mass%) of the styrenic resin composition.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present disclosure relates to a styrene-based resin composition and an injection-molded article formed using the styrene-based resin composition. [Background technology]

[0002] Styrene-unsaturated carboxylic acid resins, such as styrene-methacrylic acid copolymer resins, are excellent in heat resistance, transparency, rigidity, and appearance, and are inexpensive, and therefore are widely used in packaging materials for food containers such as lunch boxes and side dishes, foam boards for insulating housing, housing materials for lighting fixtures, and diffusion plates or light guide plates for liquid crystal televisions containing a diffusing agent. Among them, acrylic resins, which have excellent transparency, are widely used as diffusion plates or light guide plates used in the backlights of liquid crystal televisions. However, acrylic resins themselves have high hygroscopicity, which increases the rate of dimensional change, and they have low heat resistance, so that they do not currently meet the characteristics required for diffusion plates or light guide plates, particularly for in-vehicle use. For example, Patent Document 1 discloses a technique in which a composition containing a styrene-(meth)acrylic acid-based copolymer resin, an ether compound and / or an alcohol having a carbon number of 6 or more, and a phenol-based antioxidant and / or a phosphorus-based antioxidant provides excellent hue and transparency and reduces change in hue even when exposed to light for a long period of time. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-145309 A Summary of the Invention [Problem to be solved by the invention]

[0004] The technology of the above Patent Document 1 has been studied for transparency and yellowness change, but is insufficient for mechanical strength, oil resistance, and scratch resistance. In particular, when considering applications in places that people can touch directly with their hands over a long period of time, conventional styrene-unsaturated carboxylic acid resins are corroded by oil on people's hands, which can cause, for example, cracking or whitening of transparent plates, so resistance to oil is required. Therefore, an object of the present disclosure is to provide a styrene-based resin composition that can be used for a molded article having excellent weather resistance, mechanical strength, and oil resistance without reducing heat resistance and transparency. [Means for solving the problem]

[0005] The present inventors have conducted intensive research in view of the above problems, and as a result, have succeeded in realizing a styrene-based resin composition excellent in weather resistance, mechanical strength and oil resistance without reducing heat resistance and transparency by containing a styrene-unsaturated carboxylic acid-based resin (A), a (meth)acrylic resin (B), a light stabilizer (C) and an ultraviolet absorber (D) in predetermined amounts, and have completed the present invention. That is, the present disclosure is as follows.

[0006] [1] The present disclosure relates to a styrene-unsaturated carboxylic acid resin (A) having a styrene-based monomer unit (1) and an unsaturated carboxylic acid-based monomer unit (a1) in an amount of 10% by mass or more and 100% by mass or less; A styrene-based resin composition comprising: 0% by mass or more and 90% by mass or less of a (meth)acrylic resin (B) having an unsaturated carboxylic acid monomer unit (b1); The styrene-based resin composition contains 0 to 2.0 mass % of a light stabilizer (C) and 0.001 to 2.0 mass % of an ultraviolet absorber (D) relative to the total amount (100 mass %) of the styrene-based resin composition.

[0007] [2] 10% by mass or more and less than 100% by mass of a styrene-unsaturated carboxylic acid resin (A) having a styrene-based monomer unit (1) and an unsaturated carboxylic acid-based monomer unit (a1); A styrene-based resin composition comprising: more than 0% by mass and not more than 90% by mass of a (meth)acrylic resin (B) having an unsaturated carboxylic acid monomer unit (b1); The styrene-based resin composition according to [1], containing 0.001 to 2.0 mass% of a light stabilizer (C) and 0.001 to 2.0 mass% of an ultraviolet absorber (D) relative to a total amount (100 mass%) of the styrene-based resin composition.

[0008] [3] The styrene-based resin composition according to [1] or [2], further comprising 0.001 to 1.0 mass% of a monohydric alcohol (E) having 10 or more carbon atoms relative to the total amount of the styrene-based resin composition.

[0009] [4] The styrene-based resin composition according to any one of [1] to [3], wherein the light stabilizer (C) is a hindered amine-based compound.

[0010] [5] The ultraviolet absorber (D) is represented by general formula (d) and general formula (d'): [ka] (In the above general formula (d), M di each independently represents a monovalent or higher aromatic group; R d represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms; L di each independently represents a divalent to pentavalent group; R 1 represents an alkyl group having 1 to 15 carbon atoms or an aralkyl group having 7 to 25 carbon atoms, provided that -CH2- in the alkyl group may be replaced with -O- or -C(=O)-, and one or more hydrogen atoms in the benzene ring in the aralkyl group may be replaced with a phenolic hydroxyl group, an alkyl group having 1 to 15 carbon atoms or a condensed ring (including a heterocycle (e.g., a benzotriazole ring)), d1 represents an integer of 0 or more and 4 or less, and d2 represents an integer of 1 or more and 4 or less. Note that, in the above general formula (d), M di and L di The wavy line connecting indicates that the compound has one or more chemical bonds that are greater than or equal to a single bond.) [ka] (In the above general formula (d'), R 5 ~R 7 each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, a phenyl group, an alkyl group having 1 to 15 carbon atoms, or a carbon atom Number 2~ represents an alkenyl group having 1 to 15 carbon atoms or an aralkyl group having 7 to 25 carbon atoms, with the proviso that -CH2- in the alkyl group may be replaced by -O- or -C(=O)-, and one or more hydrogen atoms of the benzene ring in the aralkyl group may be replaced by a phenolic hydroxyl group, an alkyl group having 1 to 15 carbon atoms or a condensed ring (including a heterocycle (e.g., a benzotriazole ring)); R 8 each independently represents a halogen atom, a hydroxyl group, a cyano group, an alkyl group having 1 to 15 carbon atoms, or a carbon atom Number 2~ 15 alkenyl group or aralkyl group having 7 to 25 carbon atoms, provided that group or the alkenyl group -CH2- in the formula (I) may be substituted with -O- or -C(=O)-, and one or more hydrogen atoms in the benzene ring in the aralkyl group may be substituted with a phenolic hydroxyl group, an alkyl group having 1 to 15 carbon atoms or a fused ring (including a heterocycle (e.g., a benzotriazole ring)). d5 represents an integer between 0 and 4, and if d5 is 2 or greater, R 8 may be the same or different.) The styrene-based resin composition according to any one of [1] to [4], wherein the compound is one or more compounds selected from the group consisting of compounds represented by the following formula:

[0011] [6] The styrene-based resin composition according to any one of [1] to [5], containing 0.001 to 0.5 mass% of one or more antioxidants selected from the group consisting of phenol-based antioxidants, phosphorus-based antioxidants, and phosphorus-based antioxidants having a hindered phenol skeleton.

[0012] [7] The styrene-based resin composition according to any one of [1] to [6], wherein the styrene-based resin composition has a Vicat softening temperature under 5 kg load (in accordance with ISO 306) of 105° C. or higher.

[0013] [8] The styrene-based resin composition according to any one of [1] to [7], wherein the (meth)acrylic resin (B) is a copolymer containing a methacrylic acid ester monomer unit and an acrylic acid ester monomer unit.

[0014] [9] The styrene-based resin composition according to any one of [1] to [8], wherein the content of the unsaturated carboxylic acid-based monomer unit (a1) is 8.5 mass% or more based on the entire styrene-unsaturated carboxylic acid-based resin (A).

[0015]

[10] The unsaturated carboxylic acid monomer unit (a1) is one or more selected from the group consisting of (meth)acrylic acid monomer units (a1-1) and (meth)acrylic acid ester monomer units (a1-2), The styrene-unsaturated carboxylic acid resin (A) is a copolymer (A1) having the styrene monomer unit (1), the (meth)acrylic acid monomer unit (a1-1), and the (meth)acrylic acid ester monomer unit (a1-2). The styrene resin composition according to any one of [1] to [9].

[0016]

[11] The styrene-based resin composition according to any one of [1] to

[10] , wherein the styrene-unsaturated carboxylic acid-based resin (A) has a Vicat softening temperature of 120° C. or higher.

[0017]

[12] The styrene-based resin composition according to any one of [1] to

[11] , having a surface scratch hardness of H or more, measured in accordance with the scratch hardness (pencil method) specified in JIS K 5600-5-4 under a pencil lead tip load of 750 g, a pencil angle of 45 degrees, and a scratch speed of 0.5 to 1.0 mm / sec.

[0018]

[13] The styrene-based resin composition according to any one of [1] to

[12] , further comprising 0.001 to 2.0 mass% of a release agent (F) based on the total amount of the styrene-based resin composition.

[0019]

[14] An injection-molded article obtained by injection molding the styrene-based resin composition according to any one of [1] to

[13] .

[0020]

[15] A lighting cover comprising the styrene-based resin composition according to any one of [1] to

[14] .

[0021]

[16] An injection-molded article for vehicle mounting, which is obtained by injection molding the styrene-based resin composition according to any one of [1] to

[15] . Effect of the Invention

[0022] According to the present disclosure, it is possible to provide a styrene-based resin composition that can be used for a molded article having excellent weather resistance, mechanical strength, and oil resistance without reducing heat resistance and transparency. According to the present disclosure, it is possible to provide a molded article for in-vehicle use that has excellent weather resistance, mechanical strength, and oil resistance without reducing heat resistance and transparency. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, an embodiment of the present invention (hereinafter, referred to as "the present embodiment") will be described in detail. Note that the present invention is not limited to the following embodiment, and can be modified in various ways within the scope of the gist of the present invention.

[0024] [Styrene-based resin composition] The styrene-based resin composition in this embodiment (hereinafter, sometimes simply referred to as a resin composition) is a resin composition containing a styrene-unsaturated carboxylic acid-based resin (A) having a styrene-based monomer unit (1) and an unsaturated carboxylic acid-based monomer unit (a1), and a (meth)acrylic resin (B) having an unsaturated carboxylic acid-based monomer unit (b1), in which the content of the styrene-unsaturated carboxylic acid-based resin (A) is 10 mass% or more and 100 mass% or less, the content of the (meth)acrylic resin (B) is 0 mass% or more and 90 mass%, and the content of the light stabilizer (C) is 0 to 2.0 mass%, and the content of the ultraviolet absorber (D) is 0.001 to 2.0 mass%, relative to the total amount (100 mass%) of the styrene-based resin composition. Furthermore, the styrene-based resin composition in the present embodiment may contain, as necessary, one or more selected from the group consisting of alcohols (E) having 10 or more carbon atoms and release agents (F). This makes it possible to provide a styrene-based resin composition that is excellent in weather resistance, mechanical strength and oil resistance without reducing heat resistance and transparency. In the styrene-based resin composition of the present embodiment, the Vicat softening temperature is preferably 110° C. or higher. In the styrene-based resin composition of the present embodiment, the surface scratch hardness (pencil method) is preferably H or more.

[0025] "Styrene-unsaturated carboxylic acid resin (A)" The styrene-unsaturated carboxylic acid resin (A) in this embodiment is a copolymer resin (hereinafter also simply referred to as resin (A)) consisting essentially of styrene monomer units (1) and unsaturated carboxylic acid monomer units (a1), and contributes to improving the heat resistance of the entire styrene resin composition. In addition, the styrene-unsaturated carboxylic acid resin (A) may further contain other monomer units (a2) other than the essential components of the styrene monomer units (1) and unsaturated carboxylic acid monomer units (a1), if necessary.

[0026] Based on the total amount (100 mass%) of the styrene-unsaturated carboxylic acid resin composition, the content of the styrene-unsaturated carboxylic acid resin (A) is 10 mass% or more and 100 mass% or less, preferably 10 mass% or more and less than 100 mass%, and more preferably 10 to 98 mass%. The lower limit of the content of the styrene-unsaturated carboxylic acid resin (A) in the styrene-based resin composition is preferably 17% by mass, 27% by mass, 37% by mass, 47% by mass, 53% by mass or more, 56% by mass or more, 59% by mass or more, 62% by mass or more, 65% by mass or more, 68% by mass or more, and 70% by mass or more in that order, and the upper limit is preferably 97% by mass or less, 95% by mass or less, 92% by mass or less, 89% by mass or less, 86% by mass or less, 83% by mass or less, 80% by mass or less, less than 80% by mass, 79% by mass or less, 78% by mass or less, 77% by mass or less, 76% by mass or less, 75% by mass or less, 74% by mass or less, and 71% by mass or less in that order. The content of the styrene-unsaturated carboxylic acid resin (A) may be any combination of the upper limit and lower limit.

[0027] In particular, by making the content of the styrene-unsaturated carboxylic acid resin (A) 10% by mass or more, it is possible to impart fluidity to the styrene resin composition and obtain a resin composition with an excellent molding cycle, and by making it 50% by mass or more, it is possible to obtain a styrene resin composition with excellent heat resistance. By making it 98% by mass or less, it is possible to fully obtain the effect of improving oil resistance by the (meth)acrylic acid resin (B) described below.

[0028] <Styrene-based monomers (1)> In the styrene-unsaturated carboxylic acid resin (A) of this embodiment, the content of the styrene-based monomer unit (1) is 60 to 98 mass%, preferably 70 to 97 mass%, more preferably 80 to 96 mass%, even more preferably 82 to 95 mass%, even more preferably 83 to 94 mass%, even more preferably 83 to 91 mass%, and particularly preferably 85 to 91.5 mass%, based on the total amount of the styrene-unsaturated carboxylic acid resin (A). If the content of the styrene-based monomer unit (1) is less than 60 mass%, the flowability is reduced, and if it is more than 98 mass%, it becomes difficult to contain the desired amount of the unsaturated carboxylic acid monomer unit (a1) described below, and the effect of improving heat resistance by the unsaturated carboxylic acid monomer unit (a1) (especially the (meth)acrylic acid monomer unit (a1-1)) is not sufficiently obtained. In the styrene-based resin composition of the present embodiment, the styrene-based monomer unit (1) is preferably contained in an amount of 50 to 85 mass%, more preferably 52 to 82 mass%, more preferably 54 to 79 mass%, and even more preferably 56 to 77 mass%, based on the total amount of the styrene-based resin composition. When the content of the styrene-based monomer (1) in the entire composition is within the above range, the effect of improving oil resistance can be sufficiently obtained.

[0029] In this embodiment, the styrene-based monomer (1) is not particularly limited, but examples thereof include styrene, α-methylstyrene, β-methylstyrene, paramethylstyrene, orthomethylstyrene, metamethylstyrene, chlorostyrene, bromostyrene, etc. From an industrial viewpoint, styrene and α-methylstyrene are particularly preferred, and styrene is more preferred. As the styrene-based monomer (1), these may be used alone or in combination of two or more. In this specification, the term "styrene monomer unit (1)" refers to a repeating unit constituting a polymer obtained by polymerizing a styrene monomer (1), and is a repeating unit (or structural unit) in which the carbon-carbon double bond in the styrene monomer (1) becomes a single bond (-CC-) through a polymerization reaction or crosslinking reaction of the styrene monomer (1). Other "monomer units" in this specification have the same meaning.

[0030] <Unsaturated carboxylic acid monomer (a1)> In the styrene-unsaturated carboxylic acid resin (A) of this embodiment, the unsaturated carboxylic acid monomer unit (a1) plays a role in improving oil resistance and compatibility with the (meth)acrylic resin (B) described below. The content of the unsaturated carboxylic acid monomer unit (a1) is 2 to 40 mass%, preferably 3 to 35 mass%, more preferably 5 to 30 mass%, even more preferably 8 to 25 mass%, even more preferably 8.5 to 20 mass%, even more preferably 9.0 to 18 mass%, and particularly preferably 10 to 15 mass% relative to the total amount of the styrene-unsaturated carboxylic acid resin (A). If the content of the unsaturated carboxylic acid monomer unit (a1) is less than 2 mass%, the effect of improving heat resistance is insufficient. In addition, if the content of the unsaturated carboxylic acid monomer unit (a1) exceeds 40 mass%, it is not preferable because the processability is reduced due to an increase in resin viscosity, bubbles are generated during molding due to an increase in water absorption, and the viscosity becomes too high during production. In particular, by setting the content of the unsaturated carboxylic acid monomer unit (a1) to 8.5 to 20 mass %, good compatibility with the (meth)acrylic resin (B) can be obtained, and a composition with excellent transparency can be obtained. The unsaturated carboxylic acid monomer unit (a1) in this embodiment includes an unsaturated carboxylic acid and its ester, and specifically includes a (meth)acrylic acid monomer unit (a1-1) and a (meth)acrylic acid ester monomer unit (a1-2).

[0031] -(Meth)acrylic acid monomer unit (a1-1)- In this embodiment, the (meth)acrylic acid monomer unit (a1-1) plays a role in improving oil resistance and heat resistance. The (meth)acrylic acid monomer (a1-1) may be acrylic acid or methacrylic acid. From an industrial viewpoint, the (meth)acrylic acid monomer unit (a1-1) may be used alone or in combination of two or more. As the (meth)acrylic acid monomer unit (a1-1), methacrylic acid, which has a large effect of improving heat resistance, is particularly preferred. In this embodiment, the range of the content of the (meth)acrylic acid monomer unit (a1-1) is preferably 2 to 40 mass% relative to the total amount of the styrene-unsaturated carboxylic acid resin (A), more preferably 3 to 20 mass%, even more preferably 4 to 17 mass%, even more preferably 8 to 14 mass%, preferably 10 to 13 mass%, even more preferably 10.3 to 13 mass%, even more preferably 10.3 to 12.5 mass%, and most preferably 10.5 to 12.5 mass%. By making the content of the (meth)acrylic acid monomer unit (a1-1) 2 mass% or more, it is possible to obtain an effect of improving heat resistance, and by making the content 40 mass% or less, it is possible to suppress an excessive increase in viscosity. In particular, by making the content in the range of 10 to 13 mass%, it is possible to obtain a styrene-unsaturated carboxylic acid resin (A) that achieves both a high effect of improving heat resistance and suppressing gel generation to a level applicable to transparent sheet applications.

[0032] -(Meth)acrylic acid ester monomer (a1-2)- In this embodiment, the (meth)acrylic acid ester monomer (a1-2) plays a role in improving oil resistance and mechanical strength. As the (meth)acrylic acid ester monomer (a1-2), a monomer represented by the following general formula (1) is used: [ka] (In the above general formula (1), R 1 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R 2 represents an ester substituent, specifically, represents an alkyl group having 1 to 12 carbon atoms. In this embodiment, the ester substituent of the (meth)acrylic acid ester monomer unit (a1-2) (R 2 The number of carbon atoms in the alkyl group is preferably 10 or less, more preferably 8 or less, even more preferably 6 or less, still more preferably 4 or less, and most preferably 3 or less. If the number exceeds 10, the effect of lowering heat resistance is significant, which is not preferable.

[0033] Examples of the (meth)acrylic acid ester monomer (a1-2) in this embodiment include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, cyclohexyl (meth)acrylate, dibenzyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, and stearyl (meth)acrylate. These can be used alone or in combination. As the (meth)acrylic acid ester monomer (a1-2), methyl (meth)acrylate, n-butyl (meth)acrylate, n-octyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate are preferred from the viewpoint of industrial availability, and methyl methacrylate is particularly preferred from the viewpoint of suppressing a decrease in heat resistance.

[0034] In this embodiment, the content of the (meth)acrylic acid ester monomer unit (a1-2) relative to the total amount of the styrene-unsaturated carboxylic acid resin (A) is, for example, preferably in the range of 0 to 50 mass%, more preferably 1 to 20 mass%, even more preferably 2 to 17 mass%, still more preferably 3 to 12 mass%, and even more preferably 4 to 10 mass%.

[0035] <Preferable form of styrene-unsaturated carboxylic acid resin (A)> The styrene-unsaturated carboxylic acid resin (A) of this embodiment may be a multicomponent polymer containing (meth)acrylic acid monomer units (a1-1) and (meth)acrylic acid ester monomer units (a1-2). That is, the styrene-unsaturated carboxylic acid resin (A) of this embodiment may be a binary copolymer of the styrene monomer (1) and the (meth)acrylic acid monomer units (a1-1), or a ternary copolymer in which the styrene monomer (1), the (meth)acrylic acid monomer units (a1-1), and the (meth)acrylic acid ester monomer units (a1-2) are copolymerized. This further improves the compatibility with the (meth)acrylic resin (B), improves the surface hardness, or improves the mechanical strength. In particular, when emphasis is placed on improving heat resistance and surface hardness, the styrene-unsaturated carboxylic acid resin (A) preferably contains a (meth)acrylic acid monomer unit (a1-1). In particular, when emphasis is placed on improving appearance and mechanical strength, the styrene-unsaturated carboxylic acid resin (A) preferably contains a (meth)acrylic acid ester monomer unit (a1-2). Furthermore, when emphasis is placed on improving compatibility with the (meth)acrylic resin (B) and on high transparency in a mixture with the resin (B), the styrene-unsaturated carboxylic acid resin (A) is preferably a ternary copolymer in which a styrene monomer (1), a (meth)acrylic acid monomer unit (a1-1), and a (meth)acrylic acid ester monomer unit (a1-2) are copolymerized. In addition, when an unsaturated carboxylic acid ester monomer unit such as the (meth)acrylic acid ester monomer unit (a1-2) is arranged adjacent to an unsaturated carboxylic acid monomer unit such as the (meth)acrylic acid unit (a1-1) in the polymer chain, an effect such as suppressing a crosslinking reaction between unsaturated carboxylic acids can be obtained. Furthermore, the styrene-unsaturated carboxylic acid resin (A) is preferably a terpolymer in which a styrene monomer (1), a (meth)acrylic acid monomer unit (a1-1), and a (meth)acrylic acid ester monomer unit (a1-2) are copolymerized. If the styrene-unsaturated carboxylic acid resin (A) is a terpolymer in which a styrene monomer (1), a (meth)acrylic acid monomer unit (a1-1), and a (meth)acrylic acid ester monomer unit (a1-2) are copolymerized, the adhesive strength between a member made of the styrene resin composition and a member made of a (meth)acrylic resin can be increased. In addition, effects are obtained in terms of heat resistance, light resistance, oil resistance, and surface hardness. In the case where the styrene-unsaturated carboxylic acid resin (A) in the present embodiment has a styrene-based monomer unit (1), a (meth)acrylic acid monomer unit (a1-1), and a (meth)acrylic acid ester monomer unit (a1-2), it is preferable that the content of the (meth)acrylic acid monomer unit (a1-1) is 2 to 30 mass% and the content of the (meth)acrylic acid ester monomer unit (a1-2) is 0 to 20 mass%, more preferably the content of the (meth)acrylic acid monomer unit (a1-1) is 3 to 20 mass%, and the content of the (meth)acrylic acid ester monomer unit (a1-2) is 1 to 17 mass%, and even more preferably the content of the (meth)acrylic acid monomer unit (a1-1) is 0 to 20 mass%, based on the total amount of the styrene-unsaturated carboxylic acid resin (A). is 3.4 to 25 mass%, and the content of the (meth)acrylic acid ester monomer units (a1-2) is 3 to 15 mass%, even more preferably, the content of the (meth)acrylic acid monomer units (a1-1) is 6 to 14 mass%, and the content of the (meth)acrylic acid ester monomer units (a1-2) is 4 to 10 mass%, even more preferably, the content of the (meth)acrylic acid monomer units (a1-1) is 9 to 12.5 mass%, and the content of the (meth)acrylic acid ester monomer units (a1-2) is 4.5 to 7.1 mass%, and most preferably, the content of the (meth)acrylic acid monomer units (a1-1) is 10.5 to 12.5 mass%, and the content of the (meth)acrylic acid ester monomer units (a1-2) is 4.5 to 7.1 mass%. By restricting the content of the (meth)acrylic acid ester monomer unit (a1-2) to 20 mass % or less, a resin composition having excellent fluidity during molding processing can be obtained. In particular, by making the content of the (meth)acrylic acid monomer unit 9 mass % or more, more preferably 10.3 mass % or more, and even more preferably 10.5 mass % or more, a resin composition having excellent heat resistance can be obtained.

[0036] When the styrene-unsaturated carboxylic acid resin (A) is a terpolymer in which a styrene monomer (1), a (meth)acrylic acid monomer unit (a1-1), and a (meth)acrylic acid ester monomer unit (a1-2) are copolymerized, the content of the (meth)acrylic acid monomer unit (a1-1) is 10.5-12.5 mass% relative to the total amount of the styrene-unsaturated carboxylic acid resin (A), the content of the (meth)acrylic acid ester monomer unit (a1-2) is 4.5-7.1 mass%, and the (meth)acrylic acid ester monomer unit (a1-2) is methyl methacrylate. This makes it possible to obtain a styrene-based resin composition having an excellent balance of moldability, heat resistance, light resistance, oil resistance, and surface hardness.

[0037] <Other monomers (a2)> The styrene-unsaturated carboxylic acid resin (A) in this embodiment may further have other monomer units (a2) other than the above-mentioned styrene monomer units (1) and unsaturated carboxylic acid monomer units (a1) (including (meth)acrylic acid monomer units (a1-1) and / or (meth)acrylic acid ester monomer units (a1-2)). That is, in this embodiment, the other monomer unit (a2) may be copolymerized with a monomer other than the two monomers shown above, without any particular limitation, as long as it is copolymerizable with the styrene-based monomer (1) and the unsaturated carboxylic acid-based monomer unit (a1) (including the (meth)acrylic acid monomer unit (a1-1) and / or the (meth)acrylic acid ester monomer unit (a1-2)), within the scope not impairing the effects of the invention. For example, examples of the other monomers (a2) other than the three monomers shown above include maleic anhydride, maleic acid, fumaric acid, itaconic acid, (meth)acrylonitrile, dimethyl maleate, dimethyl fumarate, diethyl fumarate, ethyl fumarate, maleimide, and nucleus-substituted maleimide. In this embodiment, when the styrene-unsaturated carboxylic acid resin (A) contains another monomer (a2), the content of the other monomer (a2) relative to the total amount of the styrene-unsaturated carboxylic acid resin (A) is preferably 12 mass% or less, more preferably 5 mass% or less, even more preferably 2 mass% or less, even more preferably 1 mass% or less, and even more preferably 0.5 mass% or less.

[0038] <Characteristics of styrene-unsaturated carboxylic acid resin (A)> In the styrene-unsaturated carboxylic acid resin (A) in this embodiment, the contents of the styrene-based monomer units (1), the unsaturated carboxylic acid-based monomer units (a1) (including the (meth)acrylic acid monomer units (a1-1) and the (meth)acrylic acid ester monomer units (a1-2)) and the other monomer units (a2) can be quantified using a calibration curve prepared by using a resin in which each monomer unit is known, using pyrolysis GC / MS. The melt flow rate of the styrene-unsaturated carboxylic acid resin (A) in this embodiment at 200°C is preferably in the range of 0.3 to 3.0, more preferably 0.4 to 2.5, even more preferably 0.5 to 2.0, even more preferably 0.5 to 1.8, even more preferably 0.5 to 1.1, and even more preferably 0.5 to 1.0. When the melt flow rate is 0.3 or more, it is preferable from the viewpoint of fluidity, and when it is 3.0 or less, it is preferable from the viewpoint of mechanical strength of the resin. In the present disclosure, the melt flow rate is a value measured in accordance with ISO 1133 at 200°C and a load of 5 kg (49 N).

[0039] The weight average molecular weight (Mw) of the styrene-unsaturated carboxylic acid resin (A) in this embodiment is preferably 100,000 to 400,000, more preferably 120,000 to 320,000, even more preferably 140,000 to 280,000, even more preferably 160,000 to 240,000, and most preferably 170,000 to 210,000. When the weight average molecular weight is 100,000 to 400,000, a resin having excellent practical balance between impact strength and fluidity can be obtained. The weight average molecular weight and number average molecular weight can be measured by gel permeation chromatography in terms of polystyrene standard.

[0040] The number average molecular weight (Mn) of the styrene-unsaturated carboxylic acid resin (A) of this embodiment is preferably 40,000 to 150,000, more preferably 50,000 to 120,000, and even more preferably 60,000 to 100,000.

[0041] The Z-average molecular weight (Mz) of the styrene-unsaturated carboxylic acid resin (A) of this embodiment is preferably 200,000 to 800,000, more preferably 250,000 to 500,000, and even more preferably 300,000 to 450,000.

[0042] The Vicat softening temperature of the styrene-unsaturated carboxylic acid resin (A) in this embodiment is preferably 105 to 140°C, more preferably 107 to 135°C, even more preferably 108 to 130°C, even more preferably 115°C to 127°C, even more preferably 120°C to 125°C, and even more preferably 121 to 125°C. By making the Vicat softening temperature of the styrene-unsaturated carboxylic acid resin (A) 105°C or higher, the heat resistance of the composition can be improved, and by making it 140°C or lower, it becomes easier to knead it with the (meth)acrylic resin (B). In particular, by making it 120°C or higher, a styrene resin composition with excellent heat resistance can be obtained. The Vicat softening temperature in this specification is measured in accordance with ISO 306, with a load of 5 kg and a heating rate of 50°C / hour.

[0043] <Method for producing styrene-unsaturated carboxylic acid resin (A)> The method for producing the styrene-unsaturated carboxylic acid resin (A) of this embodiment will be described below. The method for producing the styrene-unsaturated carboxylic acid resin (A) of the present embodiment preferably includes a step of mixing a styrene monomer (1), an unsaturated carboxylic acid monomer (a1) ((meth)acrylic acid monomer unit (a1-1) and / or (meth)acrylic acid ester monomer unit (a1-2)), and a solvent to prepare a mixed solution, a polymerization step of polymerizing the mixed solution to produce a reaction product, and a step of recovering the reaction product. The polymerization method for the styrene-unsaturated carboxylic acid resin (A) is not particularly limited, but for example, a radical polymerization method, among which a bulk polymerization method or a solution polymerization method can be preferably used. Specifically, the polymerization method preferably mainly comprises a polymerization step of polymerizing the polymerization raw materials (monomer components) and a devolatilization step of removing volatile matters such as unreacted monomers and polymerization solvent from the polymerization product.

[0044] In this embodiment, when the polymerization raw material is polymerized to obtain the styrene-unsaturated carboxylic acid resin (A), the polymerization raw material composition typically contains a polymerization initiator. Examples of the polymerization initiator include organic peroxides, such as peroxyketals such as 2,2-bis(t-butylperoxy)butane, 1,1-bis(t-butylperoxy)cyclohexane, and n-butyl-4,4-bis(t-butylperoxy)valerate, dialkyl peroxides such as di-t-butyl peroxide, t-butylcumyl peroxide, and dicumyl peroxide, diacyl peroxides such as acetyl peroxide and isobutyryl peroxide, peroxydicarbonates such as diisopropyl peroxydicarbonate, peroxyesters such as t-butylperoxyacetate, ketone peroxides such as acetylacetone peroxide, and hydroperoxides such as t-butyl hydroperoxide. Of these, 1,1-bis(t-butylperoxy)cyclohexane is preferred from the viewpoints of decomposition rate and polymerization rate.

[0045] In this embodiment, a chain transfer agent may be used as necessary during polymerization of the styrene-unsaturated carboxylic acid resin (A). Examples of the chain transfer agent include α-methylstyrene linear dimer, n-dodecyl mercaptan, t-dodecyl mercaptan, and n-octyl mercaptan.

[0046] As the polymerization method of the styrene-unsaturated carboxylic acid resin (A), solution polymerization using a polymerization solvent can be adopted. As the polymerization solvent, aromatic solvents such as toluene, ethylbenzene, propylbenzene, butylbenzene, etc. are preferable, and a solvent system in which the solubility of the styrene-unsaturated carboxylic acid resin (A) is adjusted by combining polar solvents such as alcohols or ketones as necessary may be used. In this embodiment, the polymerization solvent is preferably used in the range of 3 to 35 parts by mass, more preferably 5 to 30 parts by mass, relative to 100 parts by mass of the total monomers constituting the styrene-unsaturated carboxylic acid resin (A). If the polymerization solvent exceeds 35 parts by mass relative to 100 parts by mass of the total monomers, the polymerization rate decreases and the molecular weight of the resulting resin also decreases, so that the mechanical strength of the resin tends to decrease. In addition, if the polymerization solvent is less than 3 parts by mass, it may be difficult to control the heat removal during polymerization. It is preferable to add the polymerization solvent in a ratio of 3 to 35 parts by mass relative to 100 parts by mass of the total monomers, because this makes it easier to uniformize the quality and also in terms of controlling the polymerization temperature. Furthermore, when the monohydric alcohol (E) having 10 or more carbon atoms, which is an optional component of the styrene-based resin composition of this embodiment, is added from the polymerization system, it is preferable to add the (C) component in a proportion of 0.5 to 10 mass % relative to 100 mass % of the total polymerization solvent.

[0047] The apparatus used in the polymerization step for obtaining the styrene-unsaturated carboxylic acid resin (A) in this embodiment is not particularly limited, and may be appropriately selected according to a general polymerization method for styrene-based resins. For example, in the case of bulk polymerization, a polymerization apparatus having one or more completely mixed reactors connected thereto can be used. The devolatilization step is also not particularly limited, and in the case of bulk polymerization, polymerization is continued until the unreacted monomer is finally reduced to preferably 50% by mass or less, more preferably 40% by mass or less, and devolatilization treatment is performed by a known method in order to remove volatile matters such as the unreacted monomer. For example, a normal devolatilization apparatus such as a flash drum, a twin-screw devolatilizer, a thin film evaporator, or an extruder can be used, but a devolatilization apparatus with a small retention portion is preferred. The temperature of the devolatilization treatment is usually about 190 to 280° C., and more preferably 190 to 260° C. from the viewpoint of suppressing decomposition. The pressure of the devolatilization treatment is usually about 0.13 to 4.0 kPa, preferably 0.13 to 3.0 kPa, and more preferably 0.13 to 2.0 kPa. As a method for removing volatile matters, for example, a method of removing volatile matters under reduced pressure while heating, or a method of removing volatile matters through an extruder or the like designed for the purpose of removing volatile matters is preferable.

[0048] "(Meth)acrylic resin (B)" The styrene-based resin composition in this embodiment contains 0 mass % or more and 90 mass % or less of (meth)acrylic resin (B) (also simply referred to as resin (B)) based on the total amount of the styrene-based resin composition. The (meth)acrylic resin (B) has an unsaturated carboxylic acid monomer unit (b1). The inclusion of a predetermined amount of (meth)acrylic resin (B) contributes to improving the oil resistance and mechanical strength of the entire styrene-based resin composition. In this specification, the (meth)acrylic resin (B) is a general term for synthetic resins in which the content of unsaturated carboxylic acid monomer units (b1) is 50 mass% or more based on the entire (meth)acrylic resin (B). In the present invention, the number average molecular weight (Mn), weight average molecular weight (Mw) and Z average molecular weight (Mz) of the (meth)acrylic resin (B) are values ​​measured in terms of standard polystyrene based on data detected by a differential refractometer using gel permeation chromatography (GPC), as described in the Examples section below.

[0049] With respect to the total amount (100% by mass) of the styrene-based resin composition, the content of the (meth)acrylic resin (B) is 0% by mass or more and 90% by mass or less. The lower limit of the (meth)acrylic resin (B) content is preferably 0% by mass or more, more than 0% by mass, 2% by mass or more, 10% by mass or more, 11% by mass or more, 14% by mass or more, 17% by mass or more, 20% by mass or more, more than 20% by mass or more, 21% by mass or more, 22% by mass or more, 23% by mass or more, 24% by mass or more, 25% by mass or more, 26% by mass or more, and 29% by mass or more, in that order. The upper limit is preferably 83% by mass or less, 73% by mass or less, 53% by mass or less, 44% by mass or less, 41% by mass or less, 38% by mass or less, 34% by mass or less, 35% by mass or less, and 30% by mass or less, in that order. By setting the content of the (meth)acrylic resin (B) to more than 0 mass% and not more than 90 mass%, it is possible to suppress the deterioration of the heat resistance improved by the styrene-unsaturated carboxylic acid resin (A). In particular, by setting the content of the (meth)acrylic resin (B) to more than 20 mass% and not more than 53 mass%, it is possible to obtain a styrene resin composition having an excellent balance between heat resistance and oil resistance. Furthermore, when the heat resistance, moldability, and low water absorption of the resin are particularly important, the content of the (meth)acrylic resin (B) relative to the total amount (100 mass%) of the styrene-based resin composition is 0 to 30 mass%, preferably 0 to 20 mass%, more preferably 0 to 15 mass%, even more preferably 0 to 10 mass%, and still more preferably 0 to 5 mass%. The unsaturated carboxylic acid monomer unit (b1) constituting the (meth)acrylic resin (B) of this embodiment is preferably at least one repeating unit selected from the group consisting of (meth)acrylic acid monomer unit (b1-1) and (meth)acrylic acid ester monomer unit (b1-2). Therefore, the unsaturated carboxylic acid monomer unit (b1) includes the (meth)acrylic acid monomer unit (b1-1) and the (meth)acrylic acid ester monomer unit (b1-2). It is particularly preferred that the (meth)acrylic resin (B) is a copolymer having a methacrylic acid ester monomer unit and an acrylic acid ester monomer unit, which can provide improved oil resistance and mechanical strength as well as thermal decomposition resistance.

[0050] <(Meth)acrylic acid monomer (b1-1)> In this embodiment, the (meth)acrylic acid monomer (b1-1) may be acrylic acid or methacrylic acid.

[0051] <(Meth)acrylic acid ester monomer (b1-2)> The (meth)acrylic acid ester monomer units (b1) constituting the (meth)acrylic resin (B) of this embodiment include methacrylic acid ester monomer units and acrylic acid ester monomer units. Examples of the (meth)acrylic acid ester monomer (b1) include methyl acrylate, ethyl acrylate, (n-butyl) acrylate, (2-ethylhexyl) acrylate, (n-octyl) acrylate, benzyl acrylate, methyl methacrylate, butyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, (2-ethylhexyl) methacrylate, (n-octyl) methacrylate, benzyl methacrylate, and stearyl methacrylate. Methyl acrylate, (n-butyl) acrylate, methyl methacrylate, (2-ethylhexyl) methacrylate, and (n-octyl) methacrylate are preferred because they are industrially available and inexpensive. The (meth)acrylic acid ester monomer (b1-2) can be used alone or in mixture, and it is preferred to combine two (meth)acrylic acid ester monomers. As a combination of monomer units constituting the (meth)acrylic resin (B) of the present embodiment, from the viewpoint of achieving both heat resistance and thermal decomposition property, among the monomer units listed above, a copolymer of a methacrylic acid ester species and an acrylic acid ester species is preferable, and a methyl methacrylate-methyl acrylate copolymer is more preferable.

[0052] <Preferable form of (meth)acrylic resin (B)> A preferred (meth)acrylic resin (B) of this embodiment is preferably a binary or ternary copolymer, and is a methacrylic acid ester-acrylic acid ester copolymer obtained by copolymerizing a methacrylic acid ester species (methacrylic acid ester monomer units) and an acrylic acid ester species (acrylic acid ester monomer units), and is preferably a copolymer containing 0.1 to 25 mass% of acrylic acid ester monomer units relative to the total amount of the methacrylic acid ester-acrylic acid ester copolymer, more preferably a copolymer containing 0.5 to 17 mass% of acrylic acid ester monomer units, even more preferably a copolymer containing 1.0 to 7.0 mass% of acrylic acid ester monomer units, even more preferably a copolymer containing 1.2 to 4.5 mass% of acrylic acid ester monomer units, and most preferably a copolymer containing 1.5 to 3.0 mass% of acrylic acid ester monomer units.

[0053] The (meth)acrylic resin (B) of this embodiment is preferably a methyl methacrylate-methyl acrylate copolymer, more preferably a copolymer containing 0.5 to 17 mass% of methyl acrylate monomer units relative to the total amount of the copolymer, and even more preferably a copolymer containing 1.0 to 5.0 mass% of methyl acrylate monomer units, which can more effectively suppress the deterioration of the heat resistance improved by the styrene-unsaturated carboxylic acid resin (A).

[0054] In the (meth)acrylic resin (B) of this embodiment, the content of the (meth)acrylic acid ester monomer unit (b1-2) in the (meth)acrylic resin (B) is preferably 54% by mass or more, more preferably 64% by mass or more, even more preferably 71% by mass or more, even more preferably 86% by mass or more, and most preferably 91% by mass or more, based on the total amount of the (meth)acrylic resin (B). By making the content of the methacrylic acid ester monomer (b1-2) within the range of 55.0 to 100% by mass, it becomes possible to withstand kneading extrusion and molding with other resins at 300°C or less. Therefore, it is possible to suppress a significant decrease in heat resistance when the styrene-unsaturated carboxylic acid resin (A) and the (meth)acrylic resin (B) are mixed. As the type of (meth)acrylic acid ester monomer (b1-2), methyl acrylate or methyl methacrylate is preferred because of its heat resistance, industrial ease of availability, and low cost. In the (meth)acrylic resin (B) of the present embodiment, the content of the (meth)acrylic acid ester monomer unit (b1-2) in the (meth)acrylic resin (B) is preferably 100 mass % or less, more preferably 97 mass % or less, even more preferably 91 mass % or less, still more preferably 86 mass % or less, and most preferably 81 mass % or less, based on the total amount of the (meth)acrylic resin (B). In the (meth)acrylic resin (B) of this embodiment, the upper limit of the content of the (meth)acrylic acid monomer unit (b1-1) in the (meth)acrylic resin (B) is preferably 15% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, even more preferably 3% by mass or less, and most preferably 2% by mass or less, based on the total amount of the (meth)acrylic resin (B). The lower limit of the content of the (meth)acrylic acid monomer unit (b1-1) in the (meth)acrylic resin (B) is preferably 0% by mass or more, more preferably 0.5% by mass or more, even more preferably 0.7% by mass or more, even more preferably 1.0% by mass or more, and most preferably 1.5% by mass or more, based on the total amount of the (meth)acrylic resin (B). The upper and lower limits can be combined arbitrarily.

[0055] <Other monomers (b2)> The (meth)acrylic resin (B) of this embodiment may further have other monomer units (b2) other than the above-mentioned unsaturated carboxylic acid monomer units (b1) (for example, (meth)acrylic acid monomer (b1-1) and / or (meth)acrylic acid ester monomer units (b1-2)). That is, the other monomer units (b2) may be copolymerized with monomers other than the above-mentioned monomers without any particular limitation as long as they are copolymerizable with the unsaturated carboxylic acid monomer units (b1) () within a range that does not impair the effects of the invention. For example, examples of the other monomers (b2) other than the above-mentioned monomers include styrene, maleic anhydride, maleic acid, fumaric acid, itaconic acid, dimethyl maleate, dimethyl fumarate, diethyl fumarate, ethyl fumarate, maleimide, and nucleus-substituted maleimide. In this embodiment, the content of the other monomer units (b2) is preferably 0 to 30 mass%, more preferably 0 to 20 mass%, even more preferably 0 to 15 mass%, and still more preferably 0 to 7 mass%, relative to the total amount of the (meth)acrylic resin (B).

[0056] The upper limit of the weight average molecular weight (Mw) of the (meth)acrylic resin (B), calculated as standard polystyrene by the GPC method described later, is preferably 8 million or less, 6 million or less, 5 million or less, 3 million or less, 2 million or less, 1 million or less, 900,000 or less, 500,000 or less, 400,000 or less, 300,000 or less, 200,000 or less, 150,000 or less, 130,000 or less, 120,000 or less, and 110,000 or less, in that order; and the lower limit is preferably 40,000 or more, 50,000 or more, 60,000 or more, 70,000 or more, 80,000 or more, and 90,000 or more, in that order. The range of the weight average molecular weight (Mw) of the (meth)acrylic resin (B) can be any combination of the above upper and lower limits, but by making it particularly 70,000 or more, a resin composition with excellent strength can be obtained, and by making it 1,000,000 or less, the viscosity difference with the styrene-unsaturated carboxylic acid resin (A) can be suppressed. As a result, the (meth)acrylic resin (B) can be well dispersed in the styrene resin composition, and the generation of unmelted matter derived from the (meth)acrylic resin (B) can be suppressed. A molded article with good appearance can be obtained using the composition. In addition, the viscosity of the resin composition can be reduced, so that a resin composition with a good injection molding cycle can be obtained.

[0057] The weight average molecular weight (Mn) of the (meth)acrylic resin (B) is preferably in the range of 20,000 to 1,500,000, more preferably 25,000 to 300,000, and even more preferably 30,000 to 120,000, calculated as standard polystyrene by the GPC method described later.

[0058] The weight average molecular weight (Mz) of the (meth)acrylic resin (B) is preferably in the range of 80,000 to 10 million, more preferably 90,000 to 800,000, and even more preferably 100,000 to 300,000, calculated as standard polystyrene by the GPC method described later.

[0059] The polydispersity (Mw / Mn) of the (meth)acrylic resin (B) is preferably 1.1 to 6.0, more preferably 1.3 to 4.0, and even more preferably 1.5 to 3.7, calculated as standard polystyrene by the GPC method described later. In particular, by adjusting the polydispersity to 1.5 to 3.7, a styrene resin composition having an excellent balance between moldability and strength can be obtained.

[0060] The (meth)acrylic resin (B) of the present embodiment may contain a high molecular weight component of 1 million or more. The high molecular weight component of 1 million or more has an unsaturated carboxylic acid monomer (b1), and the proportion of the high molecular weight component of 1 million or more in the (meth)acrylic resin (B) contained in the styrene-based resin composition is preferably 1.0 mass% or less with respect to the total amount of the styrene-based resin composition. In addition, as a method for controlling the content of high molecular weight components of 1 million or more in the (meth)acrylic resin (B) to 1.0 mass % or less, when radically polymerizing the unsaturated carboxylic acid monomer (b1), control can be performed by adjusting the type and amount of the unsaturated carboxylic acid monomer (b1), the type and amount of the chain transfer agent, the reaction temperature, the residence time, the type and amount of the polymerization initiator, the type and amount of the polymerization solvent, etc. As described above, the (meth)acrylic resin (B) of the present embodiment contains a high molecular weight component having a molecular weight of 1,000,000 or more in an amount of 0.0 mass % or more and 1.0 mass % or less based on the total amount of the styrene-based resin composition, and in particular, the weight average molecular weight (Mw) of the (meth)acrylic resin (B) as a whole is more preferably 70,000 to 300,000.

[0061] <(Meth)acrylic acid monomer or (meth)acrylic acid ester monomer in styrene-based resin composition> In this embodiment, the content of all (meth)acrylic acid monomer units contained in the styrene-based resin composition is preferably 1 to 20 mass% relative to the total amount (100 mass%) of the styrene-based resin composition, preferably 2 to 15 mass%, more preferably 3 to 10 mass%, and even more preferably 4 to 8 mass%. When the content of the (meth)acrylic acid monomer in the entire resin composition is in the above range, the heat resistance improvement effect can be sufficiently obtained. In addition, when the balance between heat resistance and moldability is particularly important, the content of all (meth)acrylic acid monomer units contained in the styrene-based resin composition is preferably 7 to 20 mass%, preferably 8 to 18 mass%, more preferably 10 to 15 mass%, and even more preferably 10.3 to 12.5 mass% relative to the total amount (100 mass%) of the styrene-based resin composition. The total (meth)acrylic acid monomer content indicates the total amount of (meth)acrylic acid monomer units present in the styrene-based resin composition, and therefore includes the contents of (meth)acrylic acid monomer units in the resin (A), the resin (B) and any resin added as needed.

[0062] In the present embodiment, the content of all (meth)acrylic acid ester monomer units contained in the styrene-based resin composition is preferably 6 to 55 mass%, more preferably 10 to 50 mass%, more preferably 14 to 45 mass%, even more preferably 16 to 40 mass%, and still more preferably 20 to 37 mass%, based on the total amount (100 mass%) of the styrene-based resin composition. When the content of the (meth)acrylic acid ester monomer in the entire composition is within the above range, the effect of improving oil resistance and strength can be sufficiently obtained. Furthermore, when emphasis is placed on the moldability and low water absorption of the resin, the content of all (meth)acrylic acid ester monomer units contained in the styrene-based resin composition is preferably 0 to 20 mass%, more preferably 0 to 15 mass%, more preferably 0 to 10 mass%, more preferably 0 to 7 mass%, and more preferably 0 to 6 mass%, relative to the total amount (100 mass%) of the styrene-based resin composition. The total (meth)acrylic acid ester monomer content indicates the total amount of (meth)acrylic acid ester monomer units present in the styrene-based resin composition, and therefore includes the contents of (meth)acrylic acid ester monomer units in resin (A), resin (B) and any resin added as needed.

[0063] By controlling the contents of all (meth)acrylic acid monomer units and all (meth)acrylic acid ester monomer units contained in the styrene-based resin composition within the above ranges, the effect of improving heat resistance due to the (meth)acrylic acid monomer units and the effect of improving oil resistance due to the (meth)acrylic acid ester monomer units can be obtained simultaneously and efficiently, and as a result, a styrene-based resin composition having excellent heat resistance and oil resistance and a sheet molded from the same can be obtained.

[0064] <Method for producing (meth)acrylic resin (B)> The method for producing the (meth)acrylic resin (B) of the present embodiment is not particularly limited, and the (meth)acrylic resin (B) can be produced by a process such as bulk polymerization in which a (meth)acrylic acid ester monomer is polymerized with other monomers as necessary, solution polymerization in which a solvent is added, suspension polymerization in which an organic layer is dispersed in water using a suspending agent, or emulsion polymerization.

[0065] "Light stabilizer (C)" The light stabilizer (C) of this embodiment does not have ultraviolet absorbing ability by itself, but it can capture and detoxify photoradicals generated by the styrene-based resin composition absorbing ultraviolet light, thereby preventing the deterioration and coloring of the styrene-based resin composition caused by radicals. The light stabilizer (C) is preferably a hindered amine-based compound, and examples of such hindered amine-based compounds include secondary amine-type, tertiary amine-type, and N-alkoxy-type compounds. The light stabilizer (C) can be used alone or in combination of two or more types, and by using the ultraviolet absorber (D) described later in combination, a higher light resistance effect can be achieved, in other words, coloring and strength reduction after exposure due to long-term outdoor use of the styrene-based resin composition or its molded product can be suppressed. The light stabilizer (C) mainly functions on the resin surface where photoradicals are generated in large amounts, so if you want to make it more effective, a low molecular type is preferable, but it is necessary to adjust the molecular weight to an appropriate level to prevent mold contamination due to excessive bleed-out. Of the hindered amine compounds, the light stabilizer (C) is preferably a secondary amine type from the viewpoints of weather resistance and initial color tone when added.

[0066] The content of the light stabilizer (C) of this embodiment is 0% by mass to 2.0% by mass, preferably 0.001 to 2.0% by mass, with the upper limit being 1.8% by mass or less, 1.6% by mass or less, 1.4% by mass or less, 1.2% by mass or less, 1.0% by mass or less, 0.8% by mass or less, 0.7% by mass or less, 0.6% by mass or less, 0.5% by mass or less, 0.4% by mass or less, 0.3% by mass or less, 0.2% by mass or less, and 0.1% by mass or less, and the lower limit being 0.005% by mass or more, 0.010% by mass or more, 0.021% by mass or more, 0.051% by mass or more, 0.061% by mass or more, 0.071% by mass or more, 0.079% by mass or more, and 0.089% by mass or more, in that order. The content of the light stabilizer (C) can be selected from any combination of the upper and lower limits described above.

[0067] The light stabilizer (C) of this embodiment is preferably a hindered amine compound. Examples of the hindered amine compound include bis(1,2,2,6-pentamethyl-4-piperidyl)sebacate, bis(1-undecaneoxy-2,2,6,6-tetramethylpiperidin-4-yl)carbonate, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)butane-1,2,3,4-tetracarboxylate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, N'-bis(2,2,6,6-tetramethylpiperidin-4-yl)hexane-1,6-diamine, and butyl(3,5-di-t-butyl-4-hydroxybenzyl)malonate bis(1,2,2,6,6-pentamethyl-4-piperidyl). ), N,N'-1,6-hexanediylbis(N-(2,2,6,6-tetramethylpiperidin-4-yl)formamide, and the like. Specific product names include ADK STAB LA-52, ADK STAB LA-57, ADK STAB LA-63P, ADK STAB LA-68, ADK STAB LA-72, ADK STAB LA-77Y, ADK STAB LA-77G, ADK STAB LA-81 manufactured by ADEKA CORPORATION, JF-90G, JF-95 manufactured by Johoku Chemical Co., Ltd., Chimassorb 2020FDL, Chimassorb 944FDL, Tinuvn 622SF manufactured by BASF Japan Ltd., and Uvinul 4050FF manufactured by BASF Japan Ltd.

[0068] "Ultraviolet absorber (D)" The ultraviolet absorbent (D) of this embodiment can have a function of suppressing the generation of photoradicals due to ultraviolet absorption by the styrene-based resin composition, and suppressing deterioration and coloration of the resin, by absorbing ultraviolet light instead of the styrene-based resin composition and converting it into heat or chemical energy. The ultraviolet absorbent (D) is preferably a compound having two or more aromatic rings bonded via a linking group containing an atom having an unpaired electron (oxygen atom, nitrogen atom, sulfur atom, phosphorus atom, etc.), and one or more aromatic rings having a phenolic hydroxyl group. This compound can have a chemical structure that absorbs light to become excited and then converts it into chemical energy. Examples of the ultraviolet absorbent (D) of this embodiment include benzotriazole-based compounds, triazine-based compounds, benzophenone-based compounds, benzoate-based compounds, cyanoacrylate-based compounds, oxalic acid anilide-based compounds, malonic acid ester-based compounds, formamidine-based compounds, and salicylate-based compounds. These ultraviolet absorbents (D) can be used alone or in combination of two or more kinds, and by using the light stabilizer (C) and the ultraviolet absorbent (D) in combination, a higher light resistance effect can be obtained, in other words, coloring and strength reduction after exposure of the styrene resin composition can be suppressed. In addition, the ultraviolet absorbent (D) is preferably capable of absorbing the ultraviolet wavelength (250 to 350 nm) that is easily absorbed by the resin added to the styrene resin composition. A preferred ultraviolet absorber (D) in this embodiment is, for example, one or more selected from the group consisting of benzotriazole-based compounds, triazine-based compounds, benzophenone-based compounds, benzoate-based compounds, cyanoacrylate-based compounds, malonic acid ester-based compounds, and oxalic acid anilide-based compounds.

[0069] Specific examples of preferred ultraviolet absorbents (D) of the present embodiment include those represented by the following general formulas (d) and (d'): [ka] (In the above general formula (d), M di each independently represents a monovalent or higher aromatic group; R drepresents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms; L di each independently represents a divalent to pentavalent group; R 1 represents an alkyl group having 1 to 15 carbon atoms or an aralkyl group having 7 to 25 carbon atoms, with the proviso that -CH2- in the alkyl group may be replaced with -O- or -C(=O)-, and one or more hydrogen atoms in the benzene ring in the aralkyl group may be replaced with a phenolic hydroxyl group, an alkyl group having 1 to 15 carbon atoms or a condensed ring (including a heterocycle (e.g., a benzotriazole ring)), d1 represents an integer of 0 or more and 4 or less, and d2 represents an integer of 1 or more and 4 or less. Note that, in the above general formula (d), M di and L di The wavy line connecting the represents that the group has at least one chemical bond that is a single bond or more. When d1 is 0, the group is unsubstituted. [ka] (In the above general formula (d'), R 5 ~R 7 each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, a phenyl group, an alkyl group having 1 to 15 carbon atoms, or a carbon atom Number 2~ represents an alkenyl group having 1 to 15 carbon atoms or an aralkyl group having 7 to 25 carbon atoms, with the proviso that -CH2- in the alkyl group may be replaced by -O- or -C(=O)-, and one or more hydrogen atoms of the benzene ring in the aralkyl group may be replaced by a phenolic hydroxyl group, an alkyl group having 1 to 15 carbon atoms or a condensed ring (including a heterocycle (e.g., a benzotriazole ring)); R 8 each independently represents a halogen atom, a hydroxyl group, a cyano group, an alkyl group having 1 to 15 carbon atoms, or a carbon atom Number 2~ 15 alkenyl group or aralkyl group having 7 to 25 carbon atoms, provided that group or the alkenyl group -CH2- in the formula (I) may be substituted with -O- or -C(=O)-, and one or more hydrogen atoms in the benzene ring in the aralkyl group may be substituted with a phenolic hydroxyl group, an alkyl group having 1 to 15 carbon atoms or a fused ring (including a heterocycle (e.g., a benzotriazole ring)). d5 represents an integer between 0 and 4, and if d5 is 2 or greater, R 8 may be the same or different.) Preferably, the compound is one or more selected from the group consisting of compounds represented by the following formula:

[0070] In the above general formula (d), M di are each independently unsubstituted or one or more hydrogen atoms are substituted by R 2 represents a monovalent or higher aromatic group which may be substituted by 2 and is preferably a monovalent to tetravalent aromatic ring that can be substituted by the following formula (I) or (II): [ka] (In the above formula (I) or (II), R 2 each independently represents a halogen atom, a hydroxyl group, a cyano group, or an alkyl group having 1 to 15 carbon atoms, with the proviso that -CH2- in the alkyl group may be substituted with -O- or -C(=O)-, d3 represents an integer of 0 to 5, and d4 represents an integer of 0 to 4. A group represented by the following formula is more preferable. The substituent R 2 represents a halogen atom, a hydroxyl group, a cyano group or an alkyl group having 1 to 15 carbon atoms, provided that -CH2- in the alkyl group may be substituted with -O- or -C(=O)-.

[0071] In the above general formula (d), L di each independently represents a divalent to pentavalent group, and specifically, is preferably -C(=O)-, -C(=O)-O-, -OC(=O)-, -N=, -NH-C(=O)-C(=O)-NH- or a linking group represented by the following formula (III) or (IV). [ka] In the above general formula (d), d1 is an integer of 0 or more and 4 or less, and 0, 1, 2 or 3 is preferable. In the above general formula (d), d2 is L diWhen d2 is 1, L di is a divalent group. Similarly, when d2 is 2, L di is a trivalent group, and when d2 is 3, L di is a tetravalent group, and when d2 is 4, L di is a pentavalent group. Therefore, L di The number of bonds minus 1 can be d2. In the above general formula (d), R 1 represents an alkyl group having 1 to 15 carbon atoms, in which -CH2- may be replaced by -O- or -C(=O)-, and is preferably a linear or branched alkyl group having 1 to 13 carbon atoms, an alkoxy group having 1 to 13 carbon atoms, or an alkoxy group having 1 to 13 carbon atoms and an ester bond. 1 may be the same or different from each other.

[0072] Specifically, one aspect of the preferred ultraviolet absorbent (D) of the present embodiment is a compound represented by the following general formula (d). The compound represented by the above general formula (d) is more preferably one or more compounds selected from the group consisting of the following general formulas (d-1), (d-2), (d-3) and (d-4). [ka] (In the above general formula (d-1), M 1 is a group represented by the above formula (II). (In the above general formula (d-2), M 2 and M 3 is a group represented by the above formula (I), and L 1 is -N= or a group represented by the above formula (III). (In the above general formula (d-3), M 4 is a group represented by the above formula (I), and L 2 is -C(=O)-, -C(=O)-O-, or -OC(=O)-. (In the above general formula (d-4), M 5is a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, an alkyl group having 1 to 15 carbon atoms, Number 2~ R represents an alkenyl group having 15 carbon atoms, or an aralkyl group having 7 to 25 carbon atoms, preferably a group represented by the above formula (I). d4 represents an alkyl group having 1 to 10 carbon atoms, L 3 is -NH-C(=O)-C(=O)-NH-. In addition, in the above general formulas (d-1) to (d-4), "R 1 and d1" is "R 1 and d1".

[0073] The compound represented by the above general formula (d-1) includes the compound represented by the following general formula (d-1.1) or (d-1.2): [ka] [ka] (In the above general formula (d-1.1), R 3 represents a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, or an alkyl group having 1 to 15 carbon atoms, provided that -CH- in the alkyl group may be replaced by -O- or -C(=O)-, R 1 and d1 is "R 1 and d1". In the above general formula (d-1.2), R 3 represents a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, or an alkyl group having 1 to 15 carbon atoms, provided that -CH- in the alkyl group may be replaced by -O- or -C(=O)-, R 4 each independently represents a hydrogen atom, or an alkyl or alkoxy group having 1 to 15 carbon atoms, and m represents an integer of 1 or more and 5 or less.

[0074] The compound represented by the above general formula (d-2) includes the compound represented by the following general formula (d-2.1): [ka] (In the above general formula (d-2.1), M 2 and M 3 is a group represented by the above formula (I), and R 1 and d1 is "R 1 and d1).

[0075] The compound represented by the above general formula (d-3) includes the compound represented by the following general formula (d-3.1): [ka] (In the above general formula (d-3.1), M 4 is a group represented by the above formula (I), and R 1 and d1 is "R 1 and d1).

[0076] Specifically, as a preferred ultraviolet absorbent (D) in this embodiment, a compound represented by the following general formula (d-4.1) can also be suitably used. [ka] (In the above general formula (d-4.1), R 10 each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, an alkyl group having 1 to 15 carbon atoms, or a carbon atom Number 2~ and an alkenyl group having 7 to 15 carbon atoms, or an aralkyl group having 7 to 25 carbon atoms, provided that -CH2- in the alkyl group may be replaced with -O- or -C(=O)-. In the compound represented by the above general formula (d-4.1), R 10 is preferably an aralkyl group having 7 to 25 carbon atoms, more preferably an aralkyl group having 7 to 20 carbon atoms, and more preferably an aralkyl group having 7 to 18 carbon atoms.

[0077] As another preferable example of the ultraviolet absorbent (D) in this embodiment, specifically, a compound represented by the following general formula (d') can also be suitably used. [ka] (In the above general formula (d'), R 5 ~R 7 each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, a phenyl group, an alkyl group having 1 to 15 carbon atoms, or a carbon atom Number 2~ represents an alkenyl group having 1 to 15 carbon atoms or an aralkyl group having 7 to 25 carbon atoms, with the proviso that -CH2- in the alkyl group may be replaced by -O- or -C(=O)-, and one or more hydrogen atoms of the benzene ring in the aralkyl group may be replaced by a phenolic hydroxyl group, an alkyl group having 1 to 15 carbon atoms or a condensed ring (including a heterocycle (e.g., a benzotriazole ring)); R 8 each independently represents a halogen atom, a hydroxyl group, a cyano group, an alkyl group having 1 to 15 carbon atoms, or a carbon atom Number 2~ 15 alkenyl group or aralkyl group having 7 to 25 carbon atoms, provided that group or the alkenyl group -CH2- in the formula (I) may be substituted with -O- or -C(=O)-, and one or more hydrogen atoms in the benzene ring in the aralkyl group may be substituted with a phenolic hydroxyl group, an alkyl group having 1 to 15 carbon atoms or a fused ring (including a heterocycle (e.g., a benzotriazole ring)). d5 represents an integer between 0 and 4, and if d5 is 2 or greater, R 8 may be the same or different.)

[0078] R in the above general formula (d') 5 each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, a phenyl group, an alkyl group having 1 to 15 carbon atoms, or a carbon atom Number 2~ R represents an alkenyl group having 15 carbon atoms, or an aralkyl group having 7 to 25 carbon atoms, provided that -CH2- in the alkyl group may be replaced with -O- or -C(=O)-. 5 From the viewpoint of stability, a phenyl group or a hydrogen atom is particularly preferred. In the above general formula (d'), R 6 and R 7A preferred embodiment is a group represented by the following general formula (V) or a cyano group (-CN). [ka] (In the above general formula (V), R 9 is a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, an alkyl group having 1 to 15 carbon atoms, or a carbon atom Number 2~ and an alkenyl group having 15 carbon atoms, or an aralkyl group having 7 to 25 carbon atoms, provided that -CH2- in the alkyl group may be replaced with -O- or -C(=O). In addition, -CH3 in the alkyl group may be replaced with -CN. In particular, from the viewpoint of compatibility with styrene-based resins and stability, R 9 is preferably an alkyl group having 1 to 15 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms, still more preferably an alkyl group having 1 to 5 carbon atoms, still more preferably an alkyl group having 1 to 3 carbon atoms, and particularly preferably an alkyl group having 1 to 2 carbon atoms.

[0079] R in the above general formula (d') 8 A preferred embodiment of is a group represented by the above general formula (V) or an alkyl group having 1 to 15 carbon atoms, provided that -CH2- in the alkyl group may be substituted with -O- or -C(=O)-. R in the above general formula (d') 8 The position of is preferably the para position in the benzene ring in the general formula (d'). In the above general formula (d'), d5 is more preferably 0 or 1 from the viewpoint of stability.

[0080] The content of the ultraviolet absorber (D) in this embodiment is 0.001 to 2.0% by mass relative to the total amount of the styrene-based resin composition, with the upper limit being 1.8% by mass or less, 1.6% by mass or less, 1.4% by mass or less, 1.2% by mass or less, 1.0% by mass or less, 0.8% by mass or less, 0.7% by mass or less, 0.6% by mass or less, 0.5% by mass or less, 0.4% by mass or less, 0.3% by mass or less, 0.2% by mass or less, 0.1% by mass or less, and 0.05% by mass or less being preferred in this order, and the lower limit being 0.002% by mass or more, 0.004% by mass or more, 0.006% by mass or more, 0.010% by mass or more, and 0.021% by mass or more being preferred in this order. The content of the ultraviolet absorber (D) can be selected from any combination of the upper limit and lower limit values ​​described above.

[0081] Examples of the benzotriazole-based compound include 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-tert-octylphenol, 2-(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, 6-(2-benzotriazolyl)-4-tert-octyl-6'-tert-butyl-4'-methyl-2,2'-methylenebisphenol]2-(2'-hydroxy-3'-tert- butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol, and the like. Specific product names include Adeka STAB LA-32, Adeka STAB LA-36, and Adeka STAB LA-36RG manufactured by ADEKA CORPORATION, JF-77, JF-79, JF-80, JF-83, JF-832, and JAST-500 manufactured by Johoku Chemical Co., Ltd., and Tinuvin P, Tinuvin 234, Tinuvin 234FF, Tinuvin 326, Tinuvin 329, and Tinuvin 360 manufactured by BAST Japan.

[0082] Examples of the triazine-based compound include 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[2-(2-ethylhexanoyloxy)ethoxy]phenol, 2,4,6-tris(2-hydroxy-4-hexyloxy-3-methylphenyl)-1,3,5-triazine, N,N',N''-tri(m-tolyl)-1,3,5-triazine-2,4,6-triamine, 2,4,6-tris(4-butoxy-2-hydroxyphenyl)-1,3,5-triazine, 2,4-bis(2,4-dimethylphenyl)-6-(2-hydroxy-4-n-octyloxyphenyl)-1,3,5-triazine, and ethylhexanoyloxyphenyl. Examples of the compound include siltriazine, 2-(2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2,4,6-tris(2,4-dihydroxyphenyl)-1,3,5-triazine, bemotodinol, 2-(2-hydroxy-4-methoxyphenyl)-4,6-diphenyl-1,3,5-triazine, and 2-(2,4-dihydroxyphenyl)-4,6-diphenyl-1,3,5-triazine. Specific product names include Adeka STAB LA-46 and Adeka STAB LA-F70 manufactured by ADEKA Corporation, and Tinuvin 1577ED and Tinuvin 1600 manufactured by BAST Japan.

[0083] Examples of the benzophenone compounds include 2-hydroxy-4-(octyloxy)benzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,4-dihydroxybenzophenone, and 2,2',4,4'-tetrahydroxybenzophenone. Specific product names include Adeka STAB 1413 manufactured by ADEKA Corporation, and Chimassorb 81 and Chimassorb 81 FL manufactured by BAST Japan.

[0084] Examples of the cyanoacrylate compounds include 2,2-bis{[(2-cyano-3,3-diphenylacryloyl)oxy]methyl}propane-1,3-diyl=bis(2-cyano-3,3-diphenylacrylate), ethyl 2-cyano-3,3-diphenylacrylate, and 2-ethylhexyl(2Z)-3-cyano-2,3-diphenylprop-2-enoate. Specific product names include Uvinul 3030, Uvinul 3035, and Uvinul 3039 manufactured by BASF Japan Ltd.

[0085] Examples of the malonic acid ester compounds include (4-methoxybenzylidene)malonic acid ester and tetraethyl 2,2'-(1,4-phenylenedimethanilylidene)dimalonate, and specific examples thereof include HOSTAVIN PR-25 GR and HOSTAVIN B-CAP manufactured by Clariant.

[0086] The oxalic acid anilide compound may, for example, be (N-(2-ethylphenyl)-N'-(2-ethoxyphenyl)oxalic acid diamide, and specifically, may be HOSTAVIN VSU P manufactured by Clariant.

[0087] In this embodiment, the ultraviolet absorbent (D) may be used in combination of two or more kinds, and a preferred embodiment is a combination of an ultraviolet absorbent (D) capable of efficiently absorbing the region (wavelength 250-300 nm) where the ultraviolet absorption peak derived from the aromatic of the styrene resin is sensitized with photodegradation and an ultraviolet absorbent (D) capable of efficiently absorbing the region of ultraviolet light most intense on the earth (wavelength 300-400 nm). In this embodiment, a preferred embodiment of the ultraviolet absorbent (D) is particularly preferably a combination of a compound represented by the above general formula (d-2.1) and a compound represented by the above general formula (d-1.1) or a compound represented by the above general formula (d-3.1). Specifically, as the ultraviolet absorbent (D) capable of efficiently absorbing wavelengths of 250-300 nm, a combination ultraviolet absorbent in which a triazine ultraviolet absorbent is combined with a benzotriazole ultraviolet absorbent or a benzophenone ultraviolet absorbent is preferred. In particular, when the initial color tone is important, it is preferable to use a small amount of a malonate-based or oxalic acid anilide-based ultraviolet absorber, which is an ultraviolet absorber that has little absorption in the visible light region (wavelength 380 nm or more) and only absorbs in the ultraviolet region (around 250 to 350 nm), in combination with a triazine-based ultraviolet absorber that can efficiently absorb wavelengths of 250 to 300 nm. In addition, a styrene-based resin composition with excellent initial color tone can be obtained by using a malonate-based or oxalic acid anilide-based ultraviolet absorber in combination with a benzophenone-based compound or a cyanoacrylate-based compound that has little absorption in the visible light region and causes little discoloration when added.

[0088] In this embodiment, when the initial color tone is important, the ultraviolet absorber (D) is preferably an ultraviolet absorber that has little absorption in the visible light region (wavelength 380 nm or more) and has absorption in the ultraviolet region (around 250 to 350 nm). Specifically, a malonic acid ester compound and an oxalic acid anilide compound that have absorption only in the vicinity of 250 nm to 350 nm are particularly preferred as the suitable ultraviolet absorber (D). In addition, as another suitable ultraviolet absorber (D), a benzophenone compound and a cyanoacrylate compound that have little absorption in the visible light region and cause little discoloration when added can also be suitably used.

[0089] In this embodiment, as the ultraviolet absorbent (D), an ultraviolet absorbent (D) that can efficiently absorb the region (wavelength 250-300 nm) where the ultraviolet absorption peak derived from aromatic of styrene resin is sensitized with photodegradation is effective, and specifically, an example of the ultraviolet absorbent (D) that can efficiently absorb wavelength 250-300 nm is a triazine-based compound. When a triazine-based compound is used as the ultraviolet absorbent (D), sufficient effect can be obtained even if the amount added is reduced, and discoloration of the resin when added can be reduced.

[0090] "Monohydric alcohol with 10 or more carbon atoms (E)" The monohydric alcohol (E) having 10 or more carbon atoms in this embodiment (hereinafter also simply referred to as alcohol (E)) is an optional component of the styrene-based resin composition, which suppresses gelation of the styrene-unsaturated carboxylic acid-based resin (A) during molding, contributes to improving the appearance of the styrene-based resin composition and the molded article made of the styrene-based resin composition having a good appearance, and also imparts a mold release effect during injection molding. The content of the monohydric alcohol (E) having 10 or more carbon atoms is 0.01 to 1.0 mass%, preferably 0.03 to 0.8 mass%, more preferably 0.05 to 0.6 mass%, and even more preferably 0.07 to 0.5 mass%, based on the total amount (100 mass%) of the styrene-based resin composition. By making the content of the monohydric alcohol (E) having 10 or more carbon atoms 0.01 mass% or more, gelation of the styrene-unsaturated carboxylic acid-based resin (A) during molding processing can be suppressed, and by making it 1.0 mass% or less, a decrease in heat resistance and the generation of odor can be suppressed. By setting the content of the monohydric alcohol (E) having 10 or more carbon atoms to 0.07 to 0.5 mass %, sufficient gel suppression effect and mold release effect can be obtained without particularly decreasing heat resistance. In particular, when the molded article has a complex shape and excellent releasability is required, the content of the monohydric alcohol (E) having 10 or more carbon atoms is preferably 0.1 to 0.5 mass%, more preferably 0.1 to 0.4 mass%, and even more preferably 0.1 to 0.3 mass% based on the total amount of the styrene-based resin composition. When the content of the monohydric alcohol (E) having 10 or more carbon atoms is 0.1 to 0.5 mass%, a styrene-based resin composition having a particularly high mold release effect can be obtained without reducing heat resistance. If the amount of the alcohol having 10 or more carbon atoms added is less than 0.1 mass%, the mold release property is likely to decrease, particularly in molded articles having complex shapes, and if it exceeds 0.5 mass%, there is a concern that the heat resistance will decrease and mold fouling will worsen.

[0091] The monohydric alcohol (E) having 10 or more carbon atoms is an alcohol having 10 or more carbon atoms and containing one hydroxyl group, and may contain heteroatoms such as oxygen or nitrogen in the carbon chain constituting the alcohol (E), and may contain bonds other than single bonds, such as double bonds, triple bonds, ester bonds, and amide bonds in the carbon chain. The number of carbon atoms is preferably 16 or more, more preferably 17 or more, and even more preferably 18 to 50. The monohydric alcohol (E) having 10 or more carbon atoms may be contained in a styrene-based resin composition or a molded article made of a styrene-based resin composition. Therefore, by making the monohydric alcohol (E) having 10 or more carbon atoms present (or adding it) in the polymerization solution used for polymerizing the styrene-unsaturated carboxylic acid-based resin (A) or the (meth)acrylic resin (B), the final product, that is, the resin composition, can be obtained. The monohydric alcohol (E) may be allowed to remain in the styrene-unsaturated carboxylic acid resin (A) and the (meth)acrylic resin (B) or may be added when the styrene-unsaturated carboxylic acid resin (A) and the (meth)acrylic resin (B) are kneaded together and mixed in an extruder to incorporate the monohydric alcohol (E).

[0092] From the viewpoint of molecular bond stability, it is preferable that the carbon chain constituting the monohydric alcohol (E) having 10 or more carbon atoms does not contain heteroatoms and is composed only of alkyl groups. Monohydric alcohols whose carbon chain is composed only of alkyl groups have excellent thermal stability and compatibility with styrene-based resins, and therefore have the effect of suppressing mold contamination during molding. The number of carbon atoms in the alcohol is preferably 15 or more, more preferably 16 or more, even more preferably 17 to 50, and particularly preferably 18 to 30.

[0093] In this embodiment, the boiling point of the monohydric alcohol (E) having 10 or more carbon atoms is preferably 260° C. or higher, more preferably 270° C. or higher, and even more preferably 290° C. or higher. If the boiling point of the alcohol is lower than 260° C., it becomes highly volatile and tends to generate an unpleasant odor during molding, etc.

[0094] The monohydric alcohol (E) having 10 or more carbon atoms is not particularly limited, but examples thereof include 1-hexadecanol, isohexadecanol, 1-octadecanol, 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-1-octanol, isooctadecanol, 1-isoisoeicosanol, stearyl alcohol, 8-methyl-2-(4-methylhexyl)-1-decanol, 2-heptyl-1-undecanol, 2-heptyl-4-methyl-1-decanol, 2-(1,5-dimethylhexyl)-(5,9-dimethyl)-1-decanol, and polyoxyethylene alkyl ethers.

[0095] The polyoxyethylene alkyl ether is preferably a compound represented by the following general formula (2). [ka] (In the above general formula (2), R is an alkyl group having 12 to 20 carbon atoms, and X represents the average number of ethylene oxides added and is an integer of 1 to 15.)

[0096] Specific product names of preferred alcohols (E) include "Fine Oxocol 180" manufactured by Nissan Chemical Industries, Ltd., "Kalcol 8098" manufactured by Kao Corporation, and "Emulgen 109P" manufactured by Kao Corporation.

[0097] "Release agent (F)" In a preferred embodiment of this embodiment, the styrene resin composition preferably contains a release agent (F). The release agent (F) may be contained in the form of an internal lubricant (F1) kneaded when preparing the styrene resin composition, or in the form of an external lubricant (F2) dry-blended after granulation of the styrene resin composition, or in a combination of the two. The content of the release agent (F) in this embodiment is preferably 0.001 to 2.0% by mass relative to the total amount (100% by mass) of the styrene-based resin composition, and the upper limit is 1.8% by mass or less, 1.7% by mass or less, 1.6% by mass or less, 1.5% by mass or less, 1.4% by mass or less, 1.3% by mass or less, 1.2% by mass or less, 1.1% by mass or less, 1.0% by mass or less, 0.9% by mass or less, 0.8% by mass or less, 0.7% by mass or less, and The lower limit is preferably 0.003% by mass or more, 0.005% by mass or more, 0.007% by mass or more, 0.009% by mass or more, 0.012% by mass or more, 0.031% by mass or more, 0.066% by mass or more, 0.090% by mass or more, 0.11% by mass or more, 0.16% by mass or more, 0.21% by mass or more, 0.26% by mass or more, and 0.31% by mass or more. By setting the content in the range of 0.001 to 2.0% by mass, a styrene-based resin composition having excellent release properties can be obtained, and by setting the content in the range of 0.01 to 0.8% by mass, a styrene-based resin composition having an excellent balance between release properties and heat resistance can be obtained. Furthermore, particularly when the molded article has a complex shape and excellent releasability is required, a monohydric alcohol (E) having 10 or more carbon atoms is used as the release agent (F), and the content of the monohydric alcohol (E) having 10 or more carbon atoms is preferably 0.1 to 0.5 mass%, more preferably 0.1 to 0.4 mass%, and even more preferably 0.1 to 0.3 mass% relative to the total amount of the styrene-based resin composition. By setting the content of the monohydric alcohol (E) having 10 or more carbon atoms to 0.1 to 0.5 mass%, a styrene-based resin composition with particularly high release effect can be obtained without decreasing heat resistance.

[0098] When the styrene-based resin composition of the present embodiment contains a release agent (F) as the internal lubricant (F1), the content of the internal lubricant (F1) is preferably 0.05 to 2.0 mass%, more preferably 0.10 to 1.5 mass%, more preferably 0.10 to 1.0 mass%, more preferably 0.13 to 1.0 mass%, and even more preferably 0.17 to 0.8 mass%, relative to the total amount (100 mass%) of the styrene-based resin composition. In particular, by setting the content in the range of 0.13 to 1.0 mass%, excessive bleeding out can be suppressed, and a styrene-based resin composition with excellent release properties can be obtained.

[0099] When the styrene-based resin composition of the present embodiment contains a mold release agent (F) as the external lubricant (F2), the content of the mold release agent as the external lubricant (F2) is preferably in the range of 0.005 to 0.5 mass%, more preferably 0.007 to 0.2 mass%, and even more preferably 0.008 to 0.1 mass%, relative to the total amount (100 mass%) of the styrene-based resin composition. In particular, by setting the content in the range of 0.008 to 0.1 mass%, it is possible to suppress mold contamination and obtain a styrene-based resin composition with excellent mold releasability.

[0100] Examples of the release agent (F) of the present embodiment include stearic acid, zinc stearate, calcium stearate, glycerin, glycerol monostearate, glycerol distearate, ethylene bisstearic acid amide, stearic acid amide, oleic acid amide, erucic acid amide, hydrogenated castor oil, etc. From the viewpoint of the ability to impart releasability to styrene resins, stearic acid, zinc stearate, and calcium stearate are preferred.

[0101] When glycerol monostearate and / or glycerol distearate is used as the release agent (F) of this embodiment, a styrene-based resin composition having excellent releasability and initial color tone of the resin can be obtained. Specific product names of preferred release agents (F) include "Excel S-95", "Excel VS-95", "Excel O-95R", "Excel P-40", "Excel P-40P", "Excel 122V", "Excel 200", "Excel O-95N", "Excel O-95F", and "Step SS" manufactured by Kao Corporation, and "Rikemal S-100", "Rikemal S-100P", and "Rikemal H-100" manufactured by Riken Vitamin Co., Ltd. The content of glycerol monostearate or glycerol distearate used as the release agent (F) is 0.01 to 0.5 mass%, more preferably 0.03 to 0.45 mass%, even more preferably 0.05 to 0.4 mass%, even more preferably 0.05 to 0.35 mass%, even more preferably 0.08 to 0.30 mass%, even more preferably 0.10 to 0.30 mass%, and even more preferably 0.10 to 0.25 mass%, relative to the total amount (100 mass%) of the styrene-based resin composition. When glycerol monostearate or glycerol distearate is contained in an amount of 0.03 to 0.45 mass% relative to the total amount (100 mass%) of the styrene-based resin composition, a styrene-based resin composition having particularly excellent mold releasability and initial color tone of the resin can be obtained.

[0102] "Other ingredients (additives)" In addition to the above components, the styrene-based resin composition of the present embodiment may be made into a styrene-based resin composition by adding various additives generally used in styrene-based resins to achieve known effects. Examples of the additives include stabilizers, higher fatty acid surfactants, antioxidants, plasticizers, antiblocking agents, antistatic agents, antifogging agents, and mineral oils. In addition, crosslinked bodies (G) such as thermoplastic elastomers such as styrene-maleic anhydride copolymers, methyl methacrylate-butyl acrylate block copolymers, methyl methacrylate-(2-ethylhexyl) acrylate block copolymers, and styrene-butadiene block copolymers, and reinforcing materials such as core-shell type MBS resin particles may also be added to the extent that the physical properties are not impaired. There are no particular restrictions on the method of blending the crosslinked bodies (G) or additives, but examples of the method include a method of adding them during polymerization and polymerizing them, or a method of mixing the additives in advance in a blender before melt-kneading after polymerization, and then melt-kneading them in an extruder or Banbury mixer. In this embodiment, when the crosslinked body (G) is used, the content of the crosslinked body (G) is preferably 3 mass% or less, more preferably 2 mass% or less, even more preferably 1 mass% or less, even more preferably 0.5 mass% or less, still more preferably 0.1 mass% or less, even more preferably 0.05 mass% or less, particularly preferably 0.01 mass% or less, and even more particularly preferably 0.001 mass% or less, based on the total amount of the styrene-based resin composition. Reducing the amount of the crosslinked body (G) added improves transparency. Examples of the crosslinked material (G) include crosslinked resin particles made of a copolymer obtained by polymerizing one or more monomers selected from the group consisting of (meth)acrylic acid ester monomers, styrene-based monomers, and butadiene, in addition to the reinforcing materials.

[0103] In particular, from the viewpoint of stability during processing and prevention of thermal degradation, antioxidants such as octadecyl-3-(3,5-tertiary butyl-4-hydroxyphenyl)propionate, 4,6-bis(octylthiomethyl)-o-cresol, bis(3-tert-butyl-4-hydroxy-5-methylbenzenepropanoate)ethylene bis(oxyethylene), 2,2'-dimethyl-2,2'-(2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diyl)dipropane-1,1'-diyl=bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propanoate], 2-{1-[2-hydroxy-3,5-bis(2-methylbutan-2-yl)phenyl]ethyl}-4,6-bis(2-methylbutan-2-yl)phenyl hindered phenol-based antioxidants such as prop-2-enoate, 2-tert-butyl-6-[(3-tert-butyl-2-hydroxy-5-methylphenyl)methyl]-4-methylphenyl acrylate (product names include, for example, Irganox 1076 and Irganox 245 manufactured by BASF Japan, and Sumilizer GA-80, Sumilizer GS, and Sumilizer GM manufactured by Sumitomo Chemical Co., Ltd.); tris(2,4-di-tert-butylphenyl)phosphite phosphite, 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, triphenyl phosphite, triisodecyl phosphite, 3,9-dioctadecan-1-yl-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane (product names include, for example, Irgafos 168 manufactured by BASF Japan, and Adeka STAB PEP-36, Adeka STAB TPP, Adeka STAB 3010, and Adeka STAB PEP-8 manufactured by ADEKA Corporation). In addition, a phosphorus-based antioxidant having a hindered phenol skeleton, such as 6-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-t-butyldibenzo[d,f][1,3,2]dioxaphosphepine (product name: Sumilizer GP manufactured by Sumitomo Chemical Co., Ltd.) can be used. These stabilizers may be used alone or in combination of two or more. There is no particular restriction on the timing of addition, and they may be added during either the polymerization process or the devolatilization process. The stabilizer may also be mixed into the product using a mechanical device such as an extruder or mixer.

[0104] The (total) content of the antioxidant in this embodiment is 0.001 to 1.0 mass% relative to the total amount of the styrene-based resin composition. The lower limit of the preferred range of the added amount is 0.001 mass% or more, more preferably 0.005 mass% or more, more preferably 0.008 mass% or more, more preferably 0.01 mass% or more, more preferably 0.05 mass% or more, more preferably 0.08 mass% or more, more preferably 0.1 mass% or more, and more preferably 0.21 mass% or more. The upper limit of the preferred range of the added amount is 1.0 mass% or less, more preferably 0.9 mass% or less, more preferably 0.8 mass% or less, more preferably 0.7 mass% or less, more preferably 0.6 mass% or less, more preferably 0.5 mass% or less, and more preferably 0.4 mass% or less. When the content of the antioxidant in the styrene-based resin composition is high, the resin is less likely to deteriorate during processing and thermal deterioration, but discoloration of the resin is more likely to occur. Furthermore, when the antioxidant content is low, deterioration during processing and thermal deterioration become more likely to occur, but discoloration of the resin becomes less likely to occur.

[0105] The (total) content of the phenolic antioxidant in this embodiment is 0.001 to 1.0 mass% with respect to the total amount of the styrene-based resin composition. The lower limit of the preferred range of the amount of the phenolic antioxidant added is 0.001 mass% or more, more preferably 0.005 mass% or more, more preferably 0.008 mass% or more, more preferably 0.01 mass% or more, more preferably 0.05 mass% or more, more preferably 0.08 mass% or more, more preferably 0.1 mass% or more, and more preferably 0.21 mass% or more. The upper limit of the preferred range of the amount added is 1.0 mass% or less, more preferably 0.9 mass% or less, more preferably 0.8 mass% or less, more preferably 0.7 mass% or less, more preferably 0.6 mass% or less, more preferably 0.5 mass% or less, and more preferably 0.4 mass% or less. When the content of the phenolic antioxidant in the styrene-based resin composition is high, the resin is less likely to deteriorate during processing and thermal deterioration, but discoloration of the resin is more likely to occur. Furthermore, when the antioxidant content is low, deterioration during processing and thermal deterioration become more likely to occur, but discoloration of the resin becomes less likely to occur.

[0106] The (total) content of the phosphorus-based antioxidant in this embodiment is 0.001 to 1.0 mass% with respect to the total amount of the styrene-based resin composition. The lower limit of the preferred range of the amount of the phosphorus-based antioxidant added is 0.001 mass% or more, more preferably 0.005 mass% or more, more preferably 0.008 mass% or more, more preferably 0.01 mass% or more, more preferably 0.05 mass% or more, more preferably 0.08 mass% or more, more preferably 0.1 mass% or more, and more preferably 0.21 mass% or more. The upper limit of the preferred range of the amount added is 1.0 mass% or less, more preferably 0.9 mass% or less, more preferably 0.8 mass% or less, more preferably 0.7 mass% or less, more preferably 0.6 mass% or less, more preferably 0.5 mass% or less, and more preferably 0.4 mass% or less. When the content of the phosphorus-based antioxidant in the styrene-based resin composition is high, the resin is less likely to deteriorate during processing and thermal deterioration, but discoloration of the resin is more likely to occur. Furthermore, when the antioxidant content is low, deterioration during processing and thermal deterioration become more likely to occur, but discoloration of the resin becomes less likely to occur.

[0107] In this embodiment, when the phenolic antioxidant and the phosphorus-based antioxidant are used in combination, the substance amount ratio of the phenolic antioxidant to the phosphorus-based antioxidant is phenolic antioxidant:phosphorus-based antioxidant=5:1 to 1:5, more preferably 4:1 to 1:4, even more preferably 3:1 to 1:3, even more preferably 2:1 to 1:3, even more preferably 1:1 to 1:3, and even more preferably 1:1 to 1:2.8. The above blending ratio of the antioxidants can be particularly effective in preventing discoloration of the resin.

[0108] In this embodiment, among phenolic antioxidants, Sumilizer GS (compound name: 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate) or Sumilizer GM (compound name: 2-tert-butyl-6-[(3-tert-butyl-2-hydroxy-5-methylphenyl)methyl]-4-methylphenyl acrylate) can capture and neutralize alkyl radicals generated by light or thermal degradation, and is used in combination with a phosphorus-based antioxidant to improve thermal stability, particularly during processing, and to suppress discoloration of the resin due to thermal degradation, etc.

[0109] In this embodiment, among the phosphorus-based antioxidants, Irgafos168 (compound name: tris(2,4-di-tertiarybutylphenyl)phosphite) has a particularly excellent hydrolysis resistance effect and can be suitably used for water-absorbent resins and under high humidity conditions. Furthermore, among the phosphorus-based antioxidants, ADK STAB PEP-36 (compound name: 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane), ADK STAB TPP (compound name: triphenyl phosphite), ADK STAB 3010 (compound name: triisodecyl phosphite, ADK STAB PEP-8 (compound name: 3,9-dioctadecan-1-yl-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane) are highly effective in imparting heat stability during processing and are resistant to discoloration.

[0110] In this embodiment, sulfur-based antioxidants may also be used, such as dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate, pentaerythrityl tetrakis(3-laurylthiopropionate), ditridecyl-3,3'-thiodipropionate, and 2-mercaptobenzimidazole.

[0111] In the present embodiment, a preferred form of using the antioxidant is a combination of a phenolic antioxidant having a hindered phenol skeleton and a phosphorus-based antioxidant having a phosphorous ester structure, the total content of the antioxidants is 0.1 to 0.5 mass%, and the substance amount ratio of the phenolic antioxidant to the phosphorus-based antioxidant is phenolic antioxidant:phosphorus-based antioxidant=1:1 to 1:3. In the above case, a styrene-based resin composition excellent in initial color tone and thermal stability can be obtained.

[0112] In this embodiment, the light stabilizer (C) is preferably a compound having a hindered amine skeleton that has a function of capturing and detoxifying photoradicals generated by the styrene-based resin composition absorbing ultraviolet light, thereby preventing the deterioration and coloring of the styrene-based resin composition caused by radicals. On the other hand, antioxidants are classified into phenol-based antioxidants having a hindered phenol skeleton and phosphorus-based antioxidants having a phosphite ester structure. Since it is difficult to strictly classify antioxidants and light stabilizers (C), in this specification, when calculating the content of the light stabilizer (C) and / or antioxidant, for example, in the case of an antioxidant having both a hindered phenol skeleton and a phosphite ester structure, the amount added is calculated by counting both the phenol-based antioxidant and the phosphorus-based antioxidant. In addition, in the case of having both a hindered amine skeleton and a hindered phenol skeleton, the content is similarly calculated by counting both the light stabilizer and the phenol antioxidant.

[0113] [Physical properties of styrene-based resin composition] The physical properties of the styrene-based resin composition of the present embodiment will be described below. <Vicat softening temperature> In this embodiment, the Vicat softening temperature of the styrene-based resin composition is preferably 105° C. or higher, more preferably 110° C. or higher, even more preferably 115° C. or higher, even more preferably 118° C. or higher, and even more preferably 121° C. or higher. By setting the Vicat softening temperature to 105° C. or higher, a molded product that is less likely to undergo thermal dimensional deformation even in a car during the day can be obtained, and by setting the Vicat softening temperature to 110° C. or higher, a molded product that is less likely to undergo thermal dimensional deformation even in a car during the day in summer can be obtained. As described later, the Vicat softening temperature can be measured in accordance with ISO306 under conditions of a 5 kg load and a heating rate of 50° C. / h.

[0114] In this embodiment, the styrene-based resin composition preferably has a surface scratch hardness of at least H. The surface scratch hardness is measured in accordance with the scratch hardness (pencil method) described in JIS K 5600-5-4, with a pencil tip load of 750 g, a pencil angle of 45 degrees, and a scratch speed of 0.5 to 1.0 mm / sec. If the surface scratch hardness of a styrene resin composition is H or more, when a molded product of the styrene resin composition is used as a transparent plate for an automobile (for example, a transparent cover plate for a speedometer or a cover for a lighting device), the white spots caused by cracks, scratches, or oil stains due to human hands, etc., can be prevented. It is possible to suppress degradation etc.

[0115] <Melt mass flow rate> In this embodiment, the melt flow rate of the styrene resin composition at 200°C under a load of 5 kg is preferably in the range of 0.1 to 2.0 g / 10 min, more preferably 0.2 to 1.5 g / 10 min, even more preferably 0.4 to 1.0 g / 10 min, and even more preferably 0.5 to 1.0 g / 10 min. By making the melt flow rate 0.3 g / 10 min or more, good moldability can be obtained, and by making it 2.0 g / 10 min or less, a resin with excellent strength can be obtained. If the melt mass flow rate value is 0.5 to 1.0 g / 10 min, a resin with a particularly excellent balance between moldability and strength can be obtained.

[0116] <Conjugated diene monomer unit content> The styrene-based resin composition of the present embodiment may contain a rubber-like polymer containing a conjugated diene monomer unit, such as high impact polystyrene, MBS resin, ABS resin, styrene-based elastomer, or core-shell type butadiene rubber particles, if necessary. In the present embodiment, the content of the conjugated diene monomer unit derived from high impact polystyrene, MBS resin, ABS resin, styrene-based elastomer, core-shell type butadiene rubber particles, etc., which is added as necessary, is preferably 0 to 25 mass%, more preferably 0 to 10 mass%, more preferably 0.05 to 7 mass%, even more preferably 0.10 to 5 mass%, and even more preferably 0.20 to 3 mass% based on the entire styrene-based resin composition. By setting the content of the conjugated diene monomer unit within the above range, a composition having an excellent balance between transparency and strength can be obtained.

[0117] <Amount of styrene component and amount of unsaturated carboxylic acid component in styrene-based resin composition> The styrene resin composition in this embodiment contains a styrene component and an unsaturated carboxylic acid component. The styrene component here is a general term for the styrene monomer unit (1) and the styrene monomer unit contained in the other monomer (b2). On the other hand, the unsaturated carboxylic acid component is a general term for the unsaturated carboxylic acid monomer unit (a1) and the unsaturated carboxylic acid monomer unit (b2), in other words, a general term for unsaturated carboxylic acid monomer units which may be contained as the (meth)acrylic acid monomer unit (a1-1), the (meth)acrylic acid ester monomer unit (a1-2), the (meth)acrylic acid monomer unit (b1-1) and the (meth)acrylic acid ester monomer unit (b1-2). In the styrene resin composition of the present embodiment, the content of the styrene component is preferably 50 to 85 mass%, more preferably 55 to 83 mass%, and further preferably 58 to 80 mass%, based on the total amount (100 mass%) of the styrene resin composition. If the content is in the range of 50 to 85, a styrene resin composition having an excellent balance between moldability and heat resistance can be obtained. In the styrene resin composition of the present embodiment, the content of the unsaturated carboxylic acid component is preferably 10 to 80% by mass, more preferably 20 to 72% by mass, and even more preferably 34 to 51% by mass, based on the total amount (100% by mass) of the styrene resin composition. When the content of the unsaturated carboxylic acid component is in the range of 17 to 50% by mass, a styrene resin composition having an excellent balance of heat resistance, oil resistance, and strength can be obtained. In particular, by making it 25% by mass or more, resistance to oil exceeding 90°C can be obtained.

[0118] <(Meth)acrylic acid monomer composition in styrene-based resin composition> In this embodiment, the unsaturated carboxylic acid monomer unit is preferably a (meth)acrylic acid monomer unit, and the (meth)acrylic acid monomer unit in the styrene-based resin composition is preferably 2 to 40 mass% relative to the total amount (100 mass%) of the styrene-based resin composition, more preferably 3 to 20 mass%, even more preferably 4 to 17 mass%, even more preferably 8 to 14 mass%, preferably 10 to 13 mass%, even more preferably 10.3 to 13 mass%, even more preferably 10.3 to 12.5 mass%, and most preferably 10.5 to 12.5 mass%. By making the content of the (meth)acrylic acid monomer unit in the styrene-based resin composition 2 mass% or more, it is possible to obtain an effect of improving heat resistance, and by making the content 40 mass% or less, it is possible to suppress the viscosity from increasing too much. In particular, by making the content in the range of 10 to 13 mass%, it is possible to obtain a styrene-based resin composition that achieves both a high heat resistance improvement effect and suppression of gel generation to a level applicable to transparent sheet applications.

[0119] <(Meth)acrylic acid ester monomer composition in styrene-based resin composition> In this embodiment, the unsaturated carboxylate monomer unit is preferably a (meth)acrylate methyl monomer unit, and the (meth)acrylic acid monomer unit in the styrene resin composition is preferably contained in an amount of 6 to 55 mass%, preferably 10 to 50 mass%, more preferably 14 to 45 mass%, even more preferably 16 to 40 mass%, and even more preferably 20 to 37 mass%, based on the total amount (100 mass%) of the styrene resin composition. When the content of the (meth)acrylic acid ester monomer in the entire composition is within the above range, the effect of improving oil resistance and strength can be sufficiently obtained. Furthermore, when emphasis is placed on the moldability and low water absorption of the resin, the content of all methyl (meth)acrylate monomer units contained in the styrene-based resin composition is preferably 0 to 20 mass%, more preferably 0 to 15 mass%, more preferably 0 to 10 mass%, more preferably 0 to 7 mass%, and more preferably 0 to 6 mass%, relative to the total amount (100 mass%) of the styrene-based resin composition. The total (meth)acrylic acid ester monomer content indicates the total amount of (meth)acrylic acid ester monomer units present in the styrene-based resin composition, and therefore includes the contents of (meth)acrylic acid ester monomer units in resin (A), resin (B) and any resin added as needed.

[0120] <2mm plate haze> In this embodiment, the haze (cloudiness) of a 2 mm plate, which is a test piece formed from the styrene-based resin composition, is preferably 15% or less, more preferably 7%, even more preferably 3% or less, and most preferably 1.5% or less. In particular, by making it 3% or less, a molded product having very excellent transparency can be obtained when molded. In this embodiment, as described in the Examples below, the 2 mm plate is produced by injection molding a styrene-based resin composition into a 2 mm plate under the following conditions. Molding machine: Toshiba Machine EC60N Cylinder temperature: 220-240-220-200℃ Measurement: 45mm Holding pressure switching: 10mm Injection time: 10 seconds Cooling time: 15 seconds Injection speed: 23mm / sec Holding pressure speed: 23mm / sec Pressure retention time: 10 seconds Mold temperature: 45℃

[0121] "Composition of styrene-based resin composition" The styrene-based resin composition of the present embodiment contains resin (A), resin (B), light stabilizer (C), and ultraviolet absorber (D), and the total content of resin (A) and resin (B) is preferably 65 to 100 mass%, and more preferably 75 to 95 mass%, of the entire styrene-based resin composition. The styrene-based resin composition of the present embodiment contains resin (A), resin (B), light stabilizer (C), ultraviolet absorber (D), and additives, and the total content of resin (A), resin (B), light stabilizer (C), ultraviolet absorber (D), and additives preferably accounts for 70 to 100 mass%, and more preferably 80 to 95 mass%, of the entire styrene-based resin composition. The styrene-based resin composition of the present embodiment contains resin (A), resin (B), and resin (C), and the total content of resin (A), resin (B), and resin (C) is preferably 70 to 100 mass%, and more preferably 80 to 90 mass%, based on the entire styrene-based resin composition. The styrene-based resin composition of the present embodiment contains resin (A), resin (B), light stabilizer (C), ultraviolet absorber (D), and monohydric alcohol (E), and the total content of resin (A), resin (B), light stabilizer (C), ultraviolet absorber (D), and monohydric alcohol (E) preferably accounts for 85 to 100 mass%, and more preferably 90 to 95 mass%, of the entire styrene-based resin composition. The styrene-based resin composition of the present embodiment contains resin (A), resin (B), light stabilizer (C), ultraviolet absorber (D), monohydric alcohol (E), and release agent (F), and the total content of resin (A), resin (B), light stabilizer (C), ultraviolet absorber (D), monohydric alcohol (E), and release agent (F) preferably accounts for 70 to 100 mass%, and more preferably 80 to 90 mass%, of the entire styrene-based resin composition. The styrene-based resin composition of the present embodiment comprises resin (A), resin (B), light stabilizer (C), ultraviolet absorber (D), monohydric alcohol (E), release agent (F), and additives, and the total content of resin (A), resin (B), light stabilizer (C), ultraviolet absorber (D), monohydric alcohol (E), release agent (F), and additives preferably accounts for 85 to 100 mass%, and more preferably 90 to 95 mass%, of the entire styrene-based resin composition. "Particularly preferred form of styrene-based resin composition" A particularly preferred embodiment of this embodiment is a styrene-unsaturated carboxylic acid resin (A) having a styrene monomer unit (1) and an unsaturated carboxylic acid monomer unit (a1) in an amount of 59% by mass or more and 89% by mass or less, A styrene-based resin composition comprising: 14% by mass or more and 41% by mass or less of a (meth)acrylic resin (B) having an unsaturated carboxylic acid monomer unit (b1); The styrene-based resin composition contains 0.001 to 2.0 mass% of a light stabilizer (C) and 0.001 to 2.0 mass% of an ultraviolet absorber (D) relative to the total amount (100 mass%) of the styrene-based resin composition, The total content of styrene-based monomer units in the styrene-based resin composition is 58.8 to 71.6 mass%, The (meth)acrylic resin (B) is a copolymer containing a methyl methacrylate monomer unit and a methyl acrylate monomer unit, The styrene-based resin composition has a total content of all methyl methacrylate monomer units and all methyl acrylate monomer units in the styrene-based resin composition of 16 to 40 mass % based on the entire styrene-based resin composition. This makes it possible to provide a styrene-based resin composition which has excellent compatibility with acrylic resins, and is used for molded articles having excellent weather resistance, mechanical strength, and oil resistance without reducing heat resistance and transparency.

[0122] [Method of producing styrene-based resin composition] In this embodiment, the method for producing the styrene-based resin composition is not particularly limited to the method of blending, melting, kneading, and granulating each raw material component, and a method commonly used in the production of a styrene-based resin composition can be used. For example, the above components blended (mixed) in a drum tumbler, Henschel mixer, etc. are melted and kneaded using a Banbury mixer, a single-screw extruder, a twin-screw extruder, a kneader, etc., and granulated using a rotary cutter, a fan cutter, etc., to obtain a resin composition. The resin temperature during melting and kneading is preferably 180 to 270°C. In order to achieve a target resin temperature, it is preferable to set the cylinder temperature of the extruder, etc. to a temperature 10 to 20°C lower than the resin temperature. If the resin temperature is less than 180°C, mixing will be insufficient, which is not preferable. On the other hand, if the resin temperature exceeds 270°C, thermal decomposition of the resin will occur, which is not preferable.

[0123] [Molded products] The method for producing a molded article using the styrene-based resin composition of the present embodiment is as follows. The molded article can be produced by using the styrene-based resin composition in the above-mentioned melt kneading molding machine, or by using pellets of the obtained styrene-based resin composition as a raw material, by injection molding, injection compression molding, extrusion molding, blow molding, press molding, vacuum molding, foam molding, or the like. Among these, the injection molding method is preferred. <Injection molded products> Another aspect of the present disclosure is a molded article produced by injection molding the styrene-based resin composition described above. The molded article has excellent heat resistance, transparency, weather resistance, mechanical strength, and surface hardness, and can be suitably used for in-vehicle applications. Specifically, examples of the material include lighting covers containing the styrene-based resin composition and injection-molded articles for vehicles. EXAMPLES

[0124] The present invention will now be described in detail with reference to examples and comparative examples, but the present invention is not limited to these examples. The resins and molded articles in the examples and comparative examples were analyzed and evaluated as follows.

[0125] [Evaluation of properties of each resin and resin composition] (1) Measurement of weight average molecular weight The weight average molecular weight (Mw) of each of the resins and resin compositions produced in the Examples and Comparative Examples was measured by gel permeation chromatography (GPC) under the following conditions. Measuring equipment: Tosoh HLC-8220 Separation column: Two Tosoh TSK gel Super HZM-H (inner diameter 4.6 mm) connected in series Guard column: Tosoh TSK guard column Super HZ-H Measurement solvent: tetrahydrofuran (THF) Sample concentration: 5 mg of the measurement sample was dissolved in 10 mL of solvent and filtered through a 0.45 μm filter. Injection volume: 10μL Measurement temperature: 40℃ Flow rate: 0.35mL / min Detector: Differential refractometer The calibration curve was created using 11 types of TSK standard polystyrene (F-850, F-450, F-128, F-80, F-40, F-20, F-10, F-4, F-2, F-1, A-5000) manufactured by Tosoh Corporation. The calibration curve was created using a linear approximation equation.

[0126] (2) Measurement of Melt Mass Flow Rate (MFR) The melt mass flow rate (g / 10 min) of each of the resins and resin compositions produced in the Examples and Comparative Examples was measured at 200° C. and a load of 49 N in accordance with ISO1133.

[0127] (3) Measurement of Vicat softening temperature The Vicat softening temperature of each resin and resin composition produced in the examples and comparative examples was measured in accordance with ISO 306. The load was 50 N, and the heating rate was 50°C / h. Injection molded products with a Vicat softening temperature of over 105°C were obtained that were resistant to thermal deformation even at high temperatures of 100°C or higher.

[0128] (4) Measurement of the content of monohydric alcohol (E) having 10 or more carbon atoms and other impurities in styrene-based resin compositions The content of the monohydric alcohol (E) having 10 or more carbon atoms in the entire styrene-based resin composition was measured by gas chromatography under the following conditions. Sample preparation: 1.0 g of resin was dissolved in 5 mL of methyl ethyl ketone, and then 5 mL of hexane containing 200 μg / g of p-diethylbenzene as a standard substance was added to reprecipitate the polymer component, and the supernatant was collected and used as the measurement solution. Measurement equipment: Agilent 6850 series GC system Detector: FID Column: DB-WAX Length: 60m Film thickness: 0.50μm Diameter: 0.320mmφ Injection volume: 1μL Split ratio: 50:1 Column temperature: Hold at 100°C for 5 minutes → Raise to 130°C at 10°C / min → Raise to 180°C at 10°C / min → Hold at 180°C for 10 minutes → Raise to 220°C at 20°C / min → Hold at 220°C for 10 minutes Inlet temperature: 230℃ Detector temperature: 300℃ Carrier gas: Helium In addition, when detecting the peak of the monohydric alcohol (E) having 10 or more carbon atoms, in order to avoid overlapping with other peaks or saturation of the peak intensity, pretreatment such as the dilution rate of the sample, the column to be used, and the detection conditions may be appropriately adjusted.

[0129] (5) Measurement of the content of each monomer unit The content of each monomer unit contained in the resin compositions prepared in the Examples and Comparative Examples was measured by pyrolysis GC / MS under the following conditions. <Measurement conditions> Pyrolysis Unit Equipment: Frontier Labs PY-3030D Furnace temperature: 600℃ Boundary temperature: 300℃ GC / MS Equipment: Shimadzu GCMS-GP2020NX Column: Ultra Alloy-5 (Length 30m, film thickness 0.25μm, diameter 0.250mmφ) Column temperature: 50°C for 5 minutes, then increase at 10°C / min. From 100°C, the temperature was increased at 7°C / min and held at 300°C for 10 minutes. Inlet temperature: 300℃ Detector temperature: 300℃ Split ratio: 1 / 300 Carrier gas: Helium Detection method: Mass spectrometer (MSD) Sample amount: 50μg Detection mode: Scan mode or SIM mode In detecting each monomer peak, in order to avoid peak overlap or saturation of peak intensity, pretreatment such as dilution rate of the sample, the column to be used, and detection conditions may be appropriately adjusted.

[0130] (6) Measurement of total light transmittance, haze, and YI (yellowness index) of 2 mm plate Each of the resin compositions produced in the Examples and Comparative Examples was molded into a 2 mm plate by injection molding, and conditioned for 48 hours or more in a thermostatic room at 23°C and 50% humidity. The haze and YI were then measured using a color difference turbidity meter (COH-300A) manufactured by Nippon Denshoku Industries Co., Ltd., and the n3 average was recorded as the value. (8) Measurement of YI (yellowness index) of 300 mm long optical path test piece Each resin composition produced in the Examples and Comparative Examples was injection molded into a 300 mm long optical path test piece, which was then conditioned for 48 hours or more in a thermostatic chamber at 23°C and 50% humidity, after which the YI was measured using a Nippon Denshoku long optical path spectrophotometer ASA-1) and the n3 average was used as the value. In particular, when emphasis is placed on the initial color tone, emphasis may be placed on the YI value at the long optical path.

[0131] (9) Evaluation of oil resistance Each of the resin compositions produced in the Examples and Comparative Examples was molded into a 2.5 mm plate by injection molding, and the styrene-based resin composition plate was immersed in coconut oil (manufactured by Wako Pure Chemical Industries, Ltd.) at 100°C for 15 minutes. After that, the haze was measured using a haze meter (NDH-2000) manufactured by Nippon Denshoku Industries Co., Ltd., and the change in haze (Δhaze) before and after immersion was calculated using the following formula, and the heat oil resistance was evaluated according to the following evaluation criteria. ΔHaze = Haze after test (%) - Haze before test (%) <Evaluation criteria> ◎ Δ haze is less than 1% △ Haze is 1% to 3% △··ΔHaze is greater than 3% and less than 5% × Δ haze is greater than 5%

[0132] (10) Measurement of surface hardness Each of the resin compositions produced in the Examples and Comparative Examples was molded into a 2 mm plate by injection molding, and a scratching test was carried out in accordance with the scratch hardness (pencil method) specified in JIS K 5600-5-4 using a dolly that can adjust the pencil tip load to 750 g and the pencil angle to 45 degrees at a scratching speed of 0.5 to 1.0 mm / sec to determine the maximum pencil hardness scale at which the surface was not scratched.

[0133] (11) Measurement of surface impact strength (kg cm) Each resin composition produced in the Examples and Comparative Examples was dried in a dryer with ventilation function at 80°C for 2 hours or more, and then molded into a 0.7 mm thick sheet using a compression molding machine with a temperature setting of 250°C. The dart impact strength was measured using a film impact tester (No. 195) manufactured by Toyo Seiki Co., Ltd., and the n8 average value was recorded.

[0134] (12) Weather resistance test Each of the resin compositions produced in the Examples and Comparative Examples was molded into a 2 mm plate by injection molding, and a weather resistance test was carried out using a xenon weather meter Ci4000 manufactured by Atlas Co., Ltd. The conditions were rain, black panel temperature 62°C, and irradiance at 340 nm of 0.4 W / m 2 The color difference (ΔE) after 1000 hours was measured using a color difference turbidity meter (COH-300A) manufactured by Nippon Denshoku Industries Co., Ltd., and the n3 average value was used as the value.

[0135] [Evaluation of properties of plate-shaped molded products] Each of the resin compositions produced in the Examples and Comparative Examples was injection molded using a mold with three gates at a maximum cylinder temperature of 250°C to produce a plate-shaped molded product having dimensions of 150 mm length x 300 mm width x 3.5 mm thickness, which was then subjected to the following evaluations.

[0136] (13) Weather resistance of injection molded products The above injection molded product was placed outdoors at an altitude of 40 m, and the YI difference (ΔYI) after 2000 hours was measured using a color difference turbidity meter (COH-300A) manufactured by Nippon Denshoku Industries Co., Ltd. The average n3 value was measured and evaluated according to the following criteria. ○: ΔYI is less than 1.0 △: ΔYI is 1.0 or more and less than 2.0 ×: ΔYI is 2.0 or more

[0137] (14) Molding cycle performance 300 pieces of the above plate-shaped injection molded products were molded, and the number of products with defects in appearance, mainly caused by mold releasability, was recorded and evaluated according to the following criteria. ◎: One or less visually defective product ○: 2 or 3 visually defective products △: More than 3 but less than 12 defective products ×: 12 or more visually defective products (15) Moldability (fluidity) (15-1) Moldability (fluidity)-1 In the evaluation of the moldability (fluidity) of the examples and comparative examples, a 2 mm thick plate was molded using an injection molding machine, EC60N, manufactured by Toshiba Machine Co., Ltd., at a cylinder temperature of 210°C, a mold temperature of 45°C, and an injection pressure of 60 MPa. The evaluation was based on the following criteria. 〇: Can be molded without problems Short: A short shot (15-2) Moldability (fluidity)-2 In the evaluation of moldability (fluidity) of the examples and comparative examples, the minimum injection pressure at which molding was possible without short shots was evaluated when a 2 mm thick plate was molded at a cylinder temperature of 220°C and a mold temperature of 45°C using an injection molding machine EC60N manufactured by Toshiba Machine Co., Ltd. In this evaluation, the lower the injection pressure at which molding is possible, the more complex the molded product or the molded product having a thin wall portion can be molded at a relatively low cylinder temperature without short shots. The ability to mold at a low cylinder temperature shortens the cooling time, shortens the molding cycle, reduces volatile components, and reduces mold contamination. (16) Moldability (water absorption) In evaluating the moldability (fluidity) of the examples and comparative examples, the pellets were left to stand for 24 hours at an air temperature of 23°C and a humidity of 50%, and then 20 plates with a thickness of 2 mm were molded using an injection molding machine, EC60N, manufactured by Toshiba Machine Co., Ltd., at a cylinder temperature of 240°C, a mold temperature of 45°C, and an injection pressure of 60 MPa. The number of plates on which silver streaks caused by moisture in the resin were observed was evaluated according to the following criteria. ◎:0~1 pieces 〇:1~4 pieces △:5~9 pieces ×: 10 or more

[0138] (17) Mold contamination during injection molding When a styrene resin composition was prepared into an injection-molded piece at 220°C according to JIS K 7152, the number of shots required until deposits were observed on the mold after continuous molding was used as an index to evaluate mold fouling. The number of shots required until deposits were observed on the mold was evaluated according to the following criteria. 〇: 100 or more times △: 50~100 times ×: Less than 50 times

[0139] (18) Surface appearance of injection molded products Ten of the above injection molded articles were molded, and both surfaces of the molded articles were visually inspected for the presence or absence of foreign matter and evaluated according to the following criteria. ○: The number of foreign objects is 5 or less △: 5 or more but less than 10 foreign objects ×: 10 or more foreign objects

[0140] (19) Transparency of injection molded products The above injection molded article was cut into a size of 50 mm length x 100 mm width using an ultrasonic cutter, and the haze of the molded article was measured using a Nippon Denshoku Industries Co., Ltd. haze meter (NDH-2000). The average n3 value was measured and evaluated according to the following criteria. Good: Haze is 3.0% or less △: Haze is over 3.0% to 5.0% or less ×: Haze exceeds 5.0%

[0141] (20) Heat resistance of injection molded products The above injection molded product was placed in a thermostatic chamber set at 115° C., and after 30 minutes, it was removed and cooled to room temperature. The thermal dimensional change rate in the lateral direction was measured and evaluated according to the following criteria. ◎: Dimensional change rate is less than 0.5% ○: Dimensional change rate is 0.5% or more and less than 1% △: Dimensional change rate is 1% or more and less than 7% ×: Dimensional change rate is 7% or more

[0142] (21) Scratch resistance of injection molded products The center of the above injection molded product was randomly scratched 20 times with a fingernail, the scratched area was washed with methanol, and the fingernail marks were visually observed and evaluated according to the following criteria. ○: No claw marks found △: 1-2 claw marks are visible ×: Claw marks are found in 3 or more places

[0143] (22) Strength of injection molded products The injection molded product was cut into pieces 80mm long x 80mm wide using an ultrasonic cutter, and the film impact was measured using a Toyo Seiki Film Impact Tester (No. 195). Ten samples were measured and evaluated from the following perspectives. 〇: 2 or less destroyed samples △: 3 to 5 destroyed samples ×: 6 or more destroyed samples

[0144] [Preparation of each resin and production examples of styrene-based resin composition] The preparation of each resin and a specific method for producing the styrene-based resin composition will be described below. <Production Example of Styrene-Unsaturated Carboxylic Acid Resin (A)> -Preparation of resin a-1- A polymerization raw material composition liquid consisting of 65.5 parts by mass of styrene (containing 20 μg / g of t-butylcatechol as a polymerization inhibitor), 3.3 parts by mass of methyl methacrylate, 5.8 parts by mass of methacrylic acid (containing 50 μg / g of 4-methoxyphenol as a polymerization inhibitor), 22.9 parts by mass of ethylbenzene, 2.5 parts by mass of 2-ethyl-1-hexanol, and 0.027 parts by mass of 1,1-bis(t-butylperoxy)cyclohexane was supplied to a complete mixing reactor having a capacity of 3.6 liters at a rate of 0.8 liters / hour, and then continuously supplied to a devolatilizer connected to a single screw extruder that removes volatile components such as unreacted monomers and polymerization solvents. The polymerization temperature of the complete mixing reactor was set to 130°C. The temperature of the single screw extruder was set to 210 to 230°C, and the pressure was set to 10 torr, and volatile components such as unreacted monomers and polymerization solvents were devolatilized. The volatilized volatile components were condensed in a condenser through which a -5°C refrigerant was passed and collected as an unreacted liquid, and the styrene-based resin was collected as resin pellets. The physical properties of resin a-1 obtained by the above-mentioned analytical methods are shown in Table 1 below.

[0145] -Preparation of resins a-2, a-3, a-5 to a-13- The feed amount of each monomer and the polymerization conditions were adjusted, and resins a-2, a-3 and a-5 to a-13 were prepared in the same manner as for resin a-1. The compositions and physical properties of the obtained resins a-1 to a-3 and a-5 to a-13 are shown in Table 1.

[0146] -Preparation of resin a-4- Using only styrene as a monomer, a styrene homopolymer resin a-4 having the composition and physical properties shown in Table 1 was obtained in the same manner as above.

[0147] [Table 1]

[0148] The obtained resins a-1 to a-13 contained residual styrene monomer of about 100 to 500 μg / g, ethylbenzene of about 10 to 200 μg / g, 2-ethyl-1-hexanol of about 30 to 120 μg / g, styrene dimer and trimer of about 1000 to 5000 μg / g, and impurities derived from the residue of the polymerization raw material composition. These were quantitatively determined by the same method as that for the quantitative determination of the monohydric alcohol (E) having 10 or more carbon atoms by gas chromatography described above.

[0149] <Production Example of (Meth)acrylic Resin (B)> -Preparation of resin b-1- A 5L container equipped with an agitator was charged with 2 kg of water, 65 g of tribasic calcium phosphate, 39 g of calcium carbonate, and 0.39 g of sodium lauryl sulfate, and the suspension was prepared by mixing and stirring them. Next, 26 kg of water was charged into a 60L reactor and heated to 80°C, and suspension polymerization was prepared. After confirming that the temperature had reached 80°C and was in a constant temperature state, 1.56 kg of methyl methacrylate, 0.03 kg of methyl acrylate, 0.99 g of lauroyl peroxide, 4.33 g of n-octyl mercaptan, and the above suspension were charged as polymerization raw materials. Thereafter, suspension polymerization was carried out while maintaining the temperature at about 80°C, and after observing the exothermic peak, the temperature was raised to 92°C at a rate of 1°C / min, and the temperature was maintained at 92°C for 60 minutes. Subsequently, the mixture was cooled to 50°C, and 20% by mass of sulfuric acid was charged to dissolve the suspension. The polymerization reaction solution was then removed from the 60 L reactor and passed through a sieve with a mesh size of 1.7 mm to remove large aggregates, after which the aqueous layer and solid matter were separated in a Buchner funnel to obtain a bead-like polymer. The bead-like polymer was washed and dehydrated five times with about 20 L of distilled water on the Buchner funnel, then dried and pelletized using a single-screw extruder to obtain resin b-1 as a pellet-like resin.

[0150] -Preparation of resins b-2 to b-8- Resins b-2 to b-6 were prepared by adjusting the feed amount of each monomer and the polymerization conditions in the same manner as for the resin b-1. The compositions and physical properties of the obtained resins b-1 to b-8 are shown in Table 2.

[0151] [Table 2]

[0152] <<Monohydric alcohol (E) having 10 or more carbon atoms used in the examples>> In the examples of this specification, the following alcohol types were used as the monohydric alcohol (E) having 10 or more carbon atoms. As the monohydric alcohol (E-1), Fine Oxocol 180 (compound name: 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-1-octanol) manufactured by Nissan Chemical Industries, Ltd. was used. As the monohydric alcohol (E-2), Kalcol 8098 (compound name: stearyl alcohol) was used. As the monohydric alcohol (E-3), Emulgen 109P (polyoxyethylene (9) lauryl ether monoalcohol) manufactured by Kao Corporation was used.

[0153] As the light stabilizer (C), the compounds or products shown in Table 3 below and with chemical structures were used.

[0154] [Table 3]

[0155] Light stabilizer c-1: [ka] CAS number: 52829-07-9 Light stabilizer c-2: [ka] CAS Number: 705257-84-7 Light stabilizer C-3: [ka] CAS Number: 64022-61-3 Light stabilizer C-4: [ka] CAS Number: 41556-26-7 Light stabilizer C-5: [ka] CAS number: 101357-37-3 and 85631-01-2 mixture

[0156] As the ultraviolet absorber (D), the compounds or products shown in Table 4 and chemical structures below were used.

[0157] [Table 4]

[0158] Ultraviolet absorbers (d.1): [ka] CAS number: 22440-22-4 Ultraviolet absorbers (d.2): [ka] CAS Number: 3147-75-9 Ultraviolet absorbers (d.3): [ka] CAS Number: 371146-04-2 Ultraviolet absorbers (d.4): [ka] CAS Number: 222529-65-9 Ultraviolet absorbers (d.5): [ka] CAS Number: 1843-05-6 Ultraviolet absorbers (d.6): [ka] CAS Number: 147315-50-2 Ultraviolet absorbers (d.7): [ka] CAS Number: 178671-58-4 Ultraviolet absorbers (d.8): [ka] CAS Number: 7443-25-6 Ultraviolet absorbers (d.9): [ka] CAS Number: 6337-43-5 Ultraviolet absorbers (d.10): [ka] CAS Number: 23949-66-8

[0159] As the release agent (F) below, the compounds or products shown in Table 5 below were used.

[0160] [Table 5]

[0161] <Production Example of Crosslinked Body (G)> -Preparation of crosslinked product g-1- Production of unmelted compound MMA-nBA copolymer crosslinked beads (C) In an autoclave equipped with a stirrer, 30 parts by mass of methyl methacrylate, 70 parts by mass of n-butyl acrylate, 5 parts by mass of divinylbenzene as a crosslinking agent, 0.2 parts by mass of benzoyl peroxide as a polymerization initiator, 0.001 parts by mass of sodium dodecylbenzenesulfonate and 0.5 parts by mass of calcium phosphate tribasic as suspension stabilizers, and 200 parts by mass of pure water were charged, and polymerization was carried out at a temperature of 95°C for 6 hours and then at a temperature of 125°C for 3 hours. After the reaction was completed, washing, dehydration, and drying were carried out to obtain a crosslinked body (g-1). The average particle size of the crosslinked body (g-1) was 4 μm, and the refractive index was 1.470. -Preparation of crosslinked product g-2- In an autoclave equipped with a stirrer, 50 parts by mass of styrene, 50 parts by mass of methyl methacrylate, 5 parts by mass of divinylbenzene as a crosslinking agent, 0.2 parts by mass of benzoyl peroxide as a polymerization initiator, 0.001 parts by mass of sodium dodecylbenzenesulfonate and 0.5 parts by mass of calcium phosphate tribasic as suspension stabilizers, and 200 parts by mass of pure water were charged, and polymerization was carried out at a temperature of 95°C for 6 hours and then at a temperature of 125°C for 3 hours. After the reaction was completed, washing, dehydration, and drying were carried out to obtain a crosslinked body (g-2). The average particle size of the crosslinked body (g-2) was 8 μm and the refractive index was 1.545. -Preparation of crosslinked product g-3- In an autoclave equipped with a stirrer, 100 parts by mass of methyl methacrylate, 5 parts by mass of divinylbenzene as a crosslinking agent, 0.2 parts by mass of benzoyl peroxide as a polymerization initiator, 0.001 parts by mass of sodium dodecylbenzenesulfonate and 0.5 parts by mass of calcium phosphate tribasic as suspension stabilizers, and 200 parts by mass of pure water were charged, and polymerization was carried out at a temperature of 95°C for 6 hours and then at a temperature of 125°C for 3 hours. After the reaction was completed, washing, dehydration, and drying were carried out to obtain a crosslinked body (g-3). The average particle size of the crosslinked body (g-3) was 8 μm, and the refractive index was 1.494. -Preparation of crosslinked product g-4- In a pressure vessel equipped with a stirrer, 200 parts by mass of pure water, 0.008 parts by mass of disodium ethylenediaminetetraacetate, 0.002 parts by mass of sodium polyoxyethylene alkyl ether phosphate, 0.0012 parts by mass of ferrous sulfate, and 0.03 parts by mass of di-sodium ethylenediaminetetraacetate were charged, and after deacidification, 100 parts by mass of butadiene, 0.05 parts by mass of sodium formaldehyde sulfoxylate, and 0.2 parts by mass of paramenthane hydroperoxide were added, and then 1.4 parts by mass of sodium polyoxyethylene alkyl ether phosphate was added dropwise over 6 hours. The reaction solution was kept at pH 6.5 to 7.5 at 50°C for 124 hours, and a diene rubber latex with a conversion rate of 98% by weight and an average particle size of 0.2 μm was obtained. Next, while maintaining the rubber latex obtained above (solid content about 71 parts) at 60 ° C, 55 parts by mass of methyl methacrylate and 5 parts by mass of (n-butyl) acrylate as monomers were added over 1 hour. Simultaneously with the addition of the above monomers, 0.09 parts by mass of t-butyl hydroperoxide and 0.1 parts by mass of sodium formaldehyde sulfoxylate were started to be added, and then the entire amount was added over 2 hours while maintaining the pH of the reaction solution at 6.5 to 7.5 and the temperature at about 60 ° C. The reaction solution was further maintained at about 60 ° C. for 1 hour to prepare a graft copolymer latex with an average particle size of 200 nm, and after adding 1 part by mass of Irganox 1076 as an antioxidant, it was coagulated with an aqueous calcium chloride solution, washed with water, dehydrated and dried to obtain a crosslinked rubber polymer (g-4) as a powder. In addition to the crosslinked products shown above, the following products were used as crosslinked products in the examples and comparative examples. Cross-linked material (g-5): Mitsubishi Chemical Corporation's Metablen W-450A (product name) Crosslinked body (g-6): Techpolymer MBX-5 (product name) manufactured by Sekisui Plastics Co., Ltd.

[0162] <<Antioxidant (H) used in the examples>> In the examples of the present specification, the following two types of antioxidants were used as antioxidants. Phenolic antioxidant h-1: Irganox 1076 manufactured by BASF Japan Compound name: Octadecyl-3-(3,5-tert-butyl-4-hydroxyphenyl)propionate Phenolic antioxidant h-2: Sumilizer GA-80 manufactured by Sumitomo Chemical Co., Ltd. Compound name: 2,2'-Dimethyl-2,2'-(2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diyl)dipropane-1,1'-diyl bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propanoate] Phenolic antioxidant h-3: Sumilizer GS manufactured by Sumitomo Chemical Co., Ltd. Compound name: 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate Phosphorus-based antioxidant H-4: Irgafos168 manufactured by BASF Japan Compound name: Tris(2,4-di-tert-butylphenyl)phosphite Phosphorus-based antioxidant H-5: Adeka STAB PEP-36 manufactured by ADEKA Corporation Compound name: 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane Phosphorus-based antioxidant H-6: ADEKA Corporation ADK STAB TPP compound name: Triphenyl phosphite Phosphorus-based antioxidant H-7: Adeka STAB 3010 manufactured by ADEKA Corporation Compound name: Triisodecyl phosphite Phosphorus-based antioxidant H-8: Adeka STAB PEP-8 manufactured by ADEKA Corporation Compound name: 3,9-dioctadecan-1-yl-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane Phosphorus-based antioxidant with a hindered phenol structure h-9: Sumilizer GP manufactured by Sumitomo Chemical Co., Ltd. Compound name: 6-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-t-butyldibenzo[d,f][1,3,2]dioxaphosphepine

[0163] [Table 6]

[0164] <Production Example of Styrene-Based Resin Composition> The detailed method for producing the styrene-based resin composition will be described below. Example 1 The styrene-unsaturated carboxylic acid resin (A) was 70.0 parts by mass of resin a-1 shown in Table 1, the (meth)acrylic resin (B) was 30.0 parts by mass of resin b-1 shown in Table 2, the light stabilizer (C) was 0.12 parts by mass of light stabilizer c-1 shown in Table 3, i.e., bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, the ultraviolet absorber (D) was 0.08 parts by mass of ultraviolet absorber d-1 shown in Table 4, i.e., 2-(2-hydroxy-5-methylphenyl)benzotriazole, the monohydric alcohol (E) having 10 or more carbon atoms was 0.08 parts by mass of A 0.11 part by mass alcohol (E-1), i.e., Fine Oxocol 180 (compound name: 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-1-octanol), and a 0.13 part by mass monohydric alcohol (E-2), i.e., Kalcol 8098 (compound name: stearyl alcohol), were dry-blended, kneaded and extruded using a twin-screw extruder TEM26SS manufactured by Shibaura Machine Co., Ltd., and pelletized. Then, 0.01 part by mass of ethylene bisstearic acid amide was dry-blended as an external lubricant (F2), to obtain a styrene-based resin composition (1) as a pellet-shaped resin. The screw rotation speed was 150 rpm, the cylinder temperature was 180 to 230 ° C, and the feed rate was 10 kg / h. The resin temperature was 250 to 260 ° C. The evaluation results of the obtained styrene-based resin composition (1) and its molded product are shown in Table 7-1.

[0165] --Examples 2 to 45-- Except for changing the formulation as shown in Tables 7-1 to 7-3 below, styrene-based resin compositions (2) to (45) and molded articles thereof were obtained in the same manner as in Example 1. The evaluation results of each composition and molded article are shown in Tables 7-1 to 7-3.

[0166] [Table 7-1]

[0167] [Table 7-2]

[0168] [Table 7-3]

[0169] -Comparative Examples 1 to 6- Resin compositions and molded articles thereof of Comparative Examples 1 to 6 were obtained in the same manner as in Example 1, except that the formulation was changed as shown in the following Table 8. The evaluation results of each composition and molded article are shown in Table 8.

[0170] [Table 8]

[0171] -Examples 46 to 135- Except for changing the formulation as shown in the following Tables 9-1 to 10-3, styrene-based resin compositions (46) to (135) and molded articles thereof of Examples 46 to 135 were obtained in the same manner as in Example 1. The evaluation results of each composition and molded article are shown in Tables 9-1 to 10-3.

[0172] [Table 9-1]

[0173] [Table 9-2]

[0174] [Table 9-3]

[0175] [Table 10-1]

[0176] [Table 10-2]

[0177] [Table 10-3] [Industrial Applicability]

[0178] The styrene-based resin composition of the present disclosure is used for a molded article having excellent weather resistance, mechanical strength and oil resistance without reducing heat resistance and transparency. The molded article of the present disclosure can be widely used for applications such as materials for vehicles, packaging materials for food containers, insulation materials for houses, housing materials for lighting fixtures, materials for monitors or displays, or light guide plates or light diffusion plates.

Claims

1. a styrene-unsaturated carboxylic acid resin (A) having 69.0 to 96.4 mass% of a styrene monomer unit (1) and an unsaturated carboxylic acid monomer unit (a1) in an amount of 10 mass% or more and less than 100 mass%, A styrene-based resin composition comprising: more than 0% by mass and not more than 90% by mass of a (meth)acrylic resin (B) having an unsaturated carboxylic acid monomer unit (b1); the unsaturated carboxylic acid monomer unit (b1) is at least one repeating unit selected from the group consisting of (meth)acrylic acid monomer units (b1-1) and (meth)acrylic acid ester monomer units (b1-2); the unsaturated carboxylic acid monomer unit (a1) is one or more selected from the group consisting of (meth)acrylic acid monomer units (a1-1) and (meth)acrylic acid ester monomer units (a1-2); and the (meth)acrylic resin (B) contains a methyl methacrylate monomer unit as the (meth)acrylic acid ester monomer unit (b1-2) and one or more monomer units selected from the group consisting of a methyl acrylate monomer unit, a (n-butyl) acrylate monomer unit and a styrene monomer unit, and contains the methyl methacrylate monomer unit in an amount of 56 to 98% by mass based on the total amount of the (meth)acrylic resin (B); the styrene-unsaturated carboxylic acid resin (A) is a copolymer comprising the styrene monomer unit (1) and the (meth)acrylic acid monomer unit (a1-1) and / or the (meth)acrylic acid ester monomer (a1-2); The styrene-based resin composition contains 0 to 2.0% by mass of a light stabilizer (C) and 0.001 to 2.0% by mass of an ultraviolet absorber (D) relative to the total amount (100% by mass), the ultraviolet absorber (D) is one or more selected from the group consisting of benzotriazole-based compounds, triazine-based compounds, benzophenone-based compounds, benzoate-based compounds, cyanoacrylate-based compounds, oxalic acid anilide-based compounds, malonic acid ester-based compounds, formamidine-based compounds, and salicylate-based compounds; The styrene-based resin composition, wherein the light stabilizer (C) is a hindered amine-based compound.

2. The styrene-based resin composition according to claim 1, comprising 0.001 to 2.0 mass% of a light stabilizer (C) and 0.001 to 2.0 mass% of an ultraviolet absorber (D) relative to a total amount (100 mass%) of the styrene-based resin composition.

3. The styrene-based resin composition according to claim 1 or 2, further comprising 0.001 to 1.0 mass% of a monohydric alcohol (E) having 10 or more carbon atoms relative to the total amount (100 mass%) of the styrene-based resin composition.

4. The styrene-based resin composition according to claim 1 or 2, wherein the light stabilizer (C) is a hindered amine-based compound.

5. The ultraviolet absorber (D) is represented by general formula (d) and general formula (d'): 【Chemistry 1】 (In the above general formula (d), M ｄｉ each independently represents a monovalent or higher aromatic group; L ｄｉ each independently represents a divalent to pentavalent group; R ｄ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms; R １ represents an alkyl group having 1 to 15 carbon atoms or an aralkyl group having 7 to 25 carbon atoms, provided that -CH ２ - may be replaced by -O- or -C(=O)-, one or more hydrogen atoms of the benzene ring in the aralkyl group may be replaced by a phenolic hydroxyl group, an alkyl group having 1 to 15 carbon atoms or a condensed ring (including a heterocyclic ring), d1 represents an integer of 0 to 4, and d2 represents an integer of 1 to 4. ｄｉ and L ｄｉ The wavy line connecting indicates that the compound has one or more chemical bonds that are greater than or equal to a single bond.) 【Chemistry 2】 (In the above general formula (d'), R ５ ~R ７ each independently represents a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, a phenyl group, an alkyl group having 1 to 15 carbon atoms, an alkenyl group having 2 to 15 carbon atoms, or an aralkyl group having 7 to 25 carbon atoms, provided that -CH ２ - may be substituted with -O- or -C(=O)-, and one or more hydrogen atoms of the benzene ring in the aralkyl group may be substituted with a phenolic hydroxyl group, an alkyl group having 1 to 15 carbon atoms or a fused ring (including a heterocycle (e.g., a benzotriazole ring)); R ８ each independently represents a halogen atom, a hydroxyl group, a cyano group, an alkyl group having 1 to 15 carbon atoms, an alkenyl group having 2 to 15 carbon atoms, or an aralkyl group having 7 to 25 carbon atoms, provided that -CH ２ - may be substituted with -O- or -C(=O)-, and one or more hydrogen atoms of the benzene ring in the aralkyl group may be substituted with a phenolic hydroxyl group, an alkyl group having 1 to 15 carbon atoms or a fused ring (including a heterocycle (e.g., a benzotriazole ring)); d5 represents an integer of 0 to 4, and when d5 is 2 or more, R ８ may be the same or different.) The styrene-based resin composition according to claim 1 or 2, wherein the compound is one or more selected from the group consisting of compounds represented by the following formula:

6. The styrene-based resin composition according to claim 1 or 2, comprising 0.001 to 0.5 mass% each of one or more antioxidants selected from the group consisting of phenol-based antioxidants, phosphorus-based antioxidants, and phosphorus-based antioxidants having a hindered phenol skeleton.

7. The styrene-based resin composition according to claim 1 or 2, wherein the 5 kg load Vicat softening temperature (in accordance with ISO 306) of the styrene-based resin composition is 105° C. or higher.

8. 3. The styrene-based resin composition according to claim 1, wherein the (meth)acrylic resin (B) is a copolymer containing a methacrylic acid ester monomer unit and an acrylic acid ester monomer unit.

9. The styrene-unsaturated carboxylic acid-based resin composition according to claim 1 or 2, wherein the content of the unsaturated carboxylic acid-based monomer unit (a1) is 8.5 mass% or more based on the entire styrene-unsaturated carboxylic acid-based resin (A).

10. The styrene-unsaturated carboxylic acid resin (A) is a copolymer (A1) having the styrene monomer unit (1), the (meth)acrylic acid monomer unit (a1-1), and the (meth)acrylic acid ester monomer unit (a1-2). The styrene resin composition according to claim 9.

11. The styrene-based resin composition according to claim 1 or 2, wherein the styrene-unsaturated carboxylic acid-based resin (A) has a 5 kg load Vicat softening temperature (in accordance with ISO 306) of 120° C. or higher.

12. 3. The styrene-based resin composition according to claim 1, wherein the surface scratch hardness measured in accordance with the scratch hardness (pencil method) specified in JIS K 5600-5-4 under a pencil lead tip load of 750 g, a pencil angle of 45 degrees, and a scratching speed of 0.5 to 1.0 mm / sec is H or higher.

13. The styrene-based resin composition according to claim 1 or 2, further comprising 0.001 to 2.0 mass% of a release agent (F) relative to the total amount (100 mass%) of the styrene-based resin composition.

14. 3. An injection-molded product obtained by injection molding the styrene-based resin composition according to claim 1 or 2.

15. A lighting cover comprising the styrene-based resin composition according to claim 1 or 2.

16. 3. An injection-molded product for vehicle mounting, which is obtained by injection molding the styrene-based resin composition according to claim 1 or 2.

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