Styrene resin composition and molded article

Abstract

The purpose of the present disclosure is to provide a styrene-based resin composition for a molded article having excellent weather resistance, mechanical strength, and oil resistance without reducing heat resistance and transparency. The present disclosure is a styrene-based resin composition containing: from 10% by mass to 100% by mass (inclusive) of 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 0-90 mass% (inclusive) of a (meth) acrylic resin (B) having an unsaturated carboxylic acid monomer unit (b1), in which the styrene 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 styrene resin composition.

Description

Technical Field

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

[0002] Styrene-unsaturated carboxylic acid resins represented by styrene-methacrylic acid copolymer resins have excellent heat resistance, transparency, rigidity, appearance, and low price, so they are widely used in packaging materials for food containers such as bento and side dishes, foam boards for residential insulation materials, shell materials for lighting fixtures, etc., and diffusers or light guides for liquid crystal televisions with diffusers added. Among them, acrylic resins with excellent transparency are widely used as diffusers or light guides used in backlight sources of liquid crystal televisions. However, due to the high hygroscopicity of acrylic resins themselves, the dimensional change rate becomes large, and the heat resistance is low, so the current situation is that the characteristics required for diffusers or light guides for vehicles are not met.

[0003] For example, Patent Document 1 discloses a technique in which a composition containing a styrene-(meth)acrylic copolymer resin, an ether compound and / or an alcohol having a carbon content of 6 or higher, and a phenolic antioxidant and / or a phosphorus-containing antioxidant has excellent hue and transparency, and changes in hue are small even when exposed to light for a long time.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-145309 Summary of the invention

[0007] Problems to be solved by the invention

[0008] In the technology of Patent Document 1, the transparency and yellowness change are studied, but the mechanical strength, oil resistance, and scratch resistance are not discussed sufficiently. In particular, when considering the use of parts that people may directly touch with their hands for a long time, the conventional styrene-unsaturated carboxylic acid resin is corroded by the oil attached to the hands of people, for example, causing the transparent plate to crack or whiten, so resistance to oil is required.

[0009] Therefore, the problem to be solved by the present disclosure is to provide a styrene-based resin composition for a molded body having excellent weather resistance, mechanical strength, and oil resistance without reducing heat resistance and transparency.

[0010] Means used to solve problems

[0011] The present inventors have conducted intensive studies in view of the above problems and have succeeded in achieving a styrene resin composition having excellent weather resistance, mechanical strength and oil resistance without reducing heat resistance and transparency by containing a styrene-unsaturated carboxylic acid resin (A), a (meth)acrylic resin (B), a light stabilizer (C) and a UV absorber (D) in predetermined amounts, and a molded article for vehicle mounting using the styrene resin composition, thereby completing the present invention. That is, the present disclosure is as follows.

[0012] [1] The present invention discloses a styrene resin composition, wherein the styrene resin composition contains:

[0013] 10% by mass or more and 100% by mass or less of a styrene-unsaturated carboxylic acid resin (A) having a styrene monomer unit (1) and an unsaturated carboxylic acid monomer unit (a1); and

[0014] 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), and

[0015] The styrene-based resin composition contains 0% by mass to 2.0% by mass of a light stabilizer (C) and 0.001% by mass to 2.0% by mass of a UV absorber (D) relative to the total amount (100% by mass) of the styrene-based resin composition.

[0016] [2] The styrene resin composition according to [1], wherein the styrene resin composition contains:

[0017] 10% by mass or more and less than 100% by mass of a styrene-unsaturated carboxylic acid resin (A) having a styrene monomer unit (1) and an unsaturated carboxylic acid monomer unit (a1);

[0018] greater than 0% by mass and less than or equal to 90% by mass of a (meth)acrylic resin (B) having an unsaturated carboxylic acid monomer unit (b1), and

[0019] The styrene-based resin composition contains 0.001% by mass to 2.0% by mass of a light stabilizer (C) and 0.001% by mass to 2.0% by mass of a UV absorber (D) based on the total amount (100% by mass) of the styrene-based resin composition.

[0020] [3] The styrene-based resin composition according to [1] or [2], further comprising 0.001% by mass to 1.0% by mass of a monohydric alcohol (E) having 10 or more carbon atoms, based on the total amount of the styrene-based resin composition.

[0021] [4] The styrene resin composition according to any one of [1] to [3], wherein the light stabilizer (C) is a hindered amine compound.

[0022] [5] The styrene resin composition according to any one of [1] to [4], wherein the ultraviolet absorber (D) is one or more selected from the group consisting of compounds represented by the general formula (d) and the general formula (d′).

[0023]

[0024] (In the above general formula (d), M di Each independently represents an aromatic group having a valency of one or more, 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, wherein -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 heterocyclic ring (such as a benzotriazole ring)), d1 represents an integer of 0 to 4, and d2 represents an integer of 1 to 4. It should be noted that in the above general formula (d), M di With L di Connected wavy lines represent chemical bonds with more than one single bond.)

[0025]

[0026] (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 1 to 15 carbon atoms, or an aralkyl group having 7 to 25 carbon atoms, wherein -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 heterocyclic ring (e.g., a benzotriazole ring)),

[0027] 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 1 to 15 carbon atoms, or an aralkyl group having 7 to 25 carbon atoms, wherein -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 heterocyclic ring (e.g., a benzotriazole ring)),

[0028] d5 represents an integer of 0 or more and 4 or less. When d5 is 2 or more, R 8 They may be the same or different from each other.)

[0029] [6] The styrene resin composition as described in any one of [1] to [5], wherein the styrene resin composition contains 0.001% by mass to 0.5% by mass of one or more antioxidants selected from the group consisting of phenolic antioxidants, phosphorus-containing antioxidants and phosphorus-containing antioxidants having a hindered phenol skeleton.

[0030] [7] The styrene-based resin composition according to any one of [1] to [6], wherein the styrene-based resin composition has a 5 kg load Vicat softening temperature (according to ISO 306) of 105° C. or higher.

[0031] [8] The styrene 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.

[0032] [9] The styrene resin composition according to any one of [1] to [8], wherein the content of the unsaturated carboxylic acid monomer unit (a1) is 8.5% by mass or more based on the entire styrene-unsaturated carboxylic acid resin (A).

[0033]

[10] The styrene resin composition according to any one of [1] to [9], wherein 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)acrylate monomer units (a1-2),

[0034] 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).

[0035]

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

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

[0036]

[12] A styrene resin composition as described in any one of [1] to

[11] , wherein the surface scratch hardness of the styrene resin composition measured under the conditions of a pencil lead tip load of 750 g, a pencil angle of 45 degrees, and a scratching speed of 0.5 mm / sec to 1.0 mm / sec according to the scratch hardness (pencil method) described in JIS K 5600-5-4 is H or higher.

[0037]

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

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

[0038]

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

[13] .

[0039]

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

[14] .

[0040]

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

[15] .

[0041] Effects of the Invention

[0042] According to the present disclosure, it is possible to provide a styrene-based resin composition for a molded body having excellent weather resistance, mechanical strength, and oil resistance without reducing heat resistance and transparency.

[0043] According to the present disclosure, a molded article for vehicle mounting having excellent weather resistance, mechanical strength, and oil resistance can be provided without reducing heat resistance and transparency. DETAILED DESCRIPTION

[0044] Hereinafter, a mode for implementing the present invention (hereinafter referred to as "this embodiment") will be described in detail. It should be noted that the present invention is not limited to the following embodiment, and can be implemented with various modifications within the scope of the gist thereof.

[0045] [Styrene resin composition]

[0046] The styrene resin composition (hereinafter, sometimes simply referred to as the resin composition) in the present embodiment is a resin composition comprising: a styrene-unsaturated carboxylic acid resin (A) having a styrene monomer unit (1) and an unsaturated carboxylic acid monomer unit (a1); and a (meth)acrylic resin (B) having an unsaturated carboxylic acid monomer unit (b1), wherein the content of the styrene-unsaturated carboxylic acid resin (A) is 10% by mass or more and 100% by mass or less, and the content of the (meth)acrylic resin (B) is 0% by mass or more and 90% by mass, relative to the total amount (100% by mass) of the styrene resin composition, and the resin composition contains 0% by mass to 2.0% by mass of a light stabilizer (C) and 0.001% by mass to 2.0% by mass of an ultraviolet absorber (D).

[0047] Furthermore, the styrene-based resin composition in the present embodiment may contain one or two or more selected from the group consisting of alcohols (E) having 10 or more carbon atoms and release agents (F), as necessary.

[0048] Thereby, a styrene-based resin composition having excellent weather resistance, mechanical strength, and oil resistance can be provided without reducing heat resistance and transparency.

[0049] The Vicat softening temperature of the styrene-based resin composition in the present embodiment is preferably 110° C. or higher.

[0050] The surface scratch hardness (pencil method) of the styrene-based resin composition in the present embodiment is preferably H or more.

[0051] "Styrene-unsaturated carboxylic acid resin (A)"

[0052] The styrene-unsaturated carboxylic acid resin (A) in the present embodiment is a copolymer resin (hereinafter, also referred to as resin (A)) formed of styrene-based monomer units (1) and unsaturated carboxylic acid-based monomer units (a1) as essential components, and contributes to improving the heat resistance of the entire styrene-based resin composition. In addition, the styrene-unsaturated carboxylic acid resin (A) may further contain other monomer units (a2) in addition to the essential components such as the styrene-based monomer units (1) and the unsaturated carboxylic acid-based monomer units (a1), as required.

[0053] The content of the styrene-unsaturated carboxylic acid resin (A) is 10% to 100% by mass, 10% to less than 100% by mass, preferably 10% to 98% by mass, relative to the total amount (100% by mass) of the styrene-based resin composition. The lower limit of the content of the styrene-unsaturated carboxylic acid resin (A) in the styrene-based resin composition is more 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, and the upper limit is more 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. The content of the styrene-unsaturated carboxylic acid resin (A) may be any combination of the above upper and lower limits.

[0054] In particular, when the content of the styrene-unsaturated carboxylic acid resin (A) is 10% by mass or more, the styrene resin composition is given fluidity, and a resin composition with excellent molding cycle can be obtained. When the content of the styrene-unsaturated carboxylic acid resin (A) is 50% by mass or more, a styrene resin composition with excellent heat resistance can be obtained. When the content of the styrene-unsaturated carboxylic acid resin (A) is 98% by mass or less, the effect of improving oil resistance brought about by the (meth) acrylic resin (B) described later can be fully obtained.

[0055] <Styrene monomer (1)>

[0056] In the styrene-unsaturated carboxylic acid resin (A) of the present embodiment, the content of the styrene-based monomer units (1) is 60% to 98% by mass, preferably 70% to 97% by mass, more preferably 80% to 96% by mass, further preferably 82% to 95% by mass, further preferably 83% to 94% by mass, further preferably 83% to 91% by mass, and particularly preferably 85% to 91.5% by mass, relative to the total amount of the styrene-unsaturated carboxylic acid resin (A). When the content of the styrene-based monomer units (1) is less than 60% by mass, fluidity is reduced. When the content of the styrene-based monomer units (1) is more than 98% by mass, it is difficult to contain a desired amount of the unsaturated carboxylic acid-based monomer units (a1) described below, and the effect of improving heat resistance by the unsaturated carboxylic acid-based monomer units (a1) (particularly the (meth)acrylic acid monomer units (a1-1)) cannot be fully obtained.

[0057] In addition, the styrene resin composition of the present embodiment preferably contains 50% to 85% by mass of the styrene monomer unit (1), preferably 52% to 82% by mass, more preferably 54% to 79% by mass, and even more preferably 56% to 77% by mass, based on the total amount of the styrene resin composition. When the content of the styrene monomer (1) in the entire composition is within the above range, the effect of improving oil resistance can be sufficiently obtained.

[0058] In the present embodiment, the styrene-based monomer (1) is not particularly limited, and examples thereof include styrene, α-methylstyrene, β-methylstyrene, p-methylstyrene, o-methylstyrene, m-methylstyrene, chlorostyrene, bromostyrene, and the like. In particular, from an industrial point of view, styrene and α-methylstyrene are preferred, and styrene is more preferred. As the styrene-based monomer (1), these may be used alone or in combination of two or more.

[0059] It should be noted that the "styrene monomer unit (1)" in the present specification 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 a carbon-carbon double bond in the styrene monomer (1) is converted into a single bond (-CC-) by a polymerization reaction or a crosslinking reaction of the styrene monomer (1). Other "monomer units" in the present specification have the same meaning.

[0060] <Unsaturated Carboxylic Acid Monomer (a1)>

[0061] In the styrene-unsaturated carboxylic acid resin (A) of the present embodiment, the unsaturated carboxylic acid monomer unit (a1) plays a role in improving oil resistance and compatibility with the (meth) acrylic resin (B) described later. The content of the unsaturated carboxylic acid monomer unit (a1) is 2% to 40% by mass, preferably 3% to 35% by mass, more preferably 5% to 30% by mass, further preferably 8% to 25% by mass, further preferably 8.5% to 20% by mass, further preferably 9.0% to 18% by mass, and particularly preferably 10% to 15% by mass, relative to the total amount of the styrene-unsaturated carboxylic acid resin (A). When the content of the unsaturated carboxylic acid monomer unit (a1) is less than 2% by mass, the effect of improving heat resistance is insufficient. In addition, when the content of the unsaturated carboxylic acid monomer unit (a1) exceeds 40% by mass, the processability is reduced due to the increase in resin viscosity, bubbles are generated during molding due to the increase in water absorption, and the viscosity becomes too high during production, which is not preferred. In particular, when the content of the unsaturated carboxylic acid monomer unit (a1) is 8.5% by mass to 20% by mass, good compatibility with the (meth)acrylic resin (B) can be obtained, and a composition with excellent transparency can be obtained.

[0062] The unsaturated carboxylic acid monomer unit (a1) in the present embodiment includes unsaturated carboxylic acids and ester forms thereof, and specific examples thereof include (meth)acrylic acid monomer units (a1-1) and (meth)acrylic acid ester monomer units (a1-2).

[0063] -(Meth)acrylic acid monomer unit (a1-1)-

[0064] In the present embodiment, the (meth)acrylic acid monomer unit (a1-1) plays a role in improving oil resistance and heat resistance. Examples of the (meth)acrylic acid monomer (a1-1) include acrylic acid and methacrylic acid. In particular, from an industrial point of view, these can be used alone or in combination of two or more as the (meth)acrylic acid monomer unit (a1-1). The (meth)acrylic acid monomer unit (a1-1) is particularly preferably methacrylic acid, which has a high effect of improving heat resistance.

[0065] In the present embodiment, the content of the (meth)acrylic acid monomer unit (a1-1) is preferably in the range of 2% to 40% by mass, more preferably 3% to 20% by mass, further preferably 4% to 17% by mass, further preferably 8% to 14% by mass, preferably 10% to 13% by mass, further preferably 10.3% to 13% by mass, further preferably 10.3% to 12.5% ​​by mass, and most preferably 10.5% to 12.5% ​​by mass. When the content of the (meth)acrylic acid monomer unit (a1-1) is 2% by mass or more, the effect of improving heat resistance can be obtained, and when the content is 40% by mass or less, excessive increase in viscosity can be suppressed. In particular, when the content is in the range of 10% to 13% by mass, a styrene-unsaturated carboxylic acid resin (A) that simultaneously achieves a high heat resistance improvement effect and suppresses gel generation at a level that can be applied to transparent sheet applications can be obtained.

[0066] -(Meth)acrylate monomer (a1-2)-

[0067] In the present embodiment, the (meth)acrylate monomer (a1-2) plays a role in improving oil resistance and mechanical strength. The (meth)acrylate monomer (a1-2) is preferably represented by the following general formula (1).

[0068]

[0069] (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, an alkyl group having 1 to 12 carbon atoms. )

[0070] In this embodiment, the ester substituent (R in the above general formula (1)) of the (meth)acrylate monomer unit (a1-2) 2 ) is preferably 10 or less, more preferably 8 or less, further preferably 6 or less, further preferably 4 or less, and most preferably 3 or less. When the carbon number of the ester substituent exceeds 10, the effect of reducing heat resistance is large, which is not preferred.

[0071] As the (meth)acrylate monomer (a1-2) in the present embodiment, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, isobutyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, stearyl (meth)acrylate, etc. These (meth)acrylate monomers can be used alone or in combination. As the (meth)acrylate monomer (a1-2), methyl (meth)acrylate, n-butyl (meth)acrylate, n-octyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate are preferred from the perspective of easy industrial availability, and methyl methacrylate is particularly preferred from the perspective of suppressing a decrease in heat resistance.

[0072] In the present embodiment, the content of the (meth)acrylate 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% by mass to 50% by mass, more preferably 1% by mass to 20% by mass, further preferably 2% by mass to 17% by mass, further preferably 3% by mass to 12% by mass, and further more preferably 4% by mass to 10% by mass.

[0073] <Preferred Embodiment of Styrene-Unsaturated Carboxylic Acid Resin (A)>

[0074] The styrene-unsaturated carboxylic acid resin (A) of the present embodiment may be a multipolymer containing a (meth)acrylic acid monomer unit (a1-1) and a (meth)acrylic acid ester monomer unit (a1-2). That is, the styrene-unsaturated carboxylic acid resin (A) of the present embodiment may be a binary copolymer of a styrene monomer (1) and a (meth)acrylic acid monomer unit (a1-1), or a ternary copolymer obtained by copolymerizing a styrene monomer (1), a (meth)acrylic acid monomer unit (a1-1), and a (meth)acrylic acid ester monomer unit (a1-2). Thus, the compatibility with the (meth)acrylic acid resin (B) and the effects of improving the surface hardness or improving the mechanical strength are further obtained.

[0075] 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 addition, 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 acid resin (B) and on high transparency of the mixture with the (meth)acrylic acid resin (B), the styrene-unsaturated carboxylic acid resin (A) is preferably a terpolymer obtained by copolymerizing a styrene monomer (1), a (meth)acrylic acid monomer unit (a1-1) and a (meth)acrylic acid ester monomer unit (a1-2).

[0076] When unsaturated carboxylic acid ester monomer units such as (meth)acrylic acid ester monomer units (a1-2) and unsaturated carboxylic acid monomer units such as (meth)acrylic acid units (a1-1) are arranged adjacent to each other in the polymer chain, effects such as suppressing crosslinking reactions between unsaturated carboxylic acids can be obtained.

[0077] In addition, the styrene-unsaturated carboxylic acid resin (A) is more preferably a terpolymer obtained by copolymerizing a styrene monomer (1), a (meth)acrylic acid monomer unit (a1-1) and a (meth)acrylic acid ester monomer unit (a1-2). If the styrene-unsaturated carboxylic acid resin (A) is a terpolymer obtained by copolymerizing a styrene monomer (1), a (meth)acrylic acid monomer unit (a1-1) and a (meth)acrylic acid ester monomer unit (a1-2), the bonding strength between a member including the styrene resin composition and a member including a (meth)acrylic acid resin can be improved. In addition, effects can also be obtained in terms of heat resistance, light resistance, oil resistance and surface hardness.

[0078] In the case where the styrene-unsaturated carboxylic acid resin (A) in the present embodiment comprises a styrene-based monomer unit (1), a (meth)acrylic acid monomer unit (a1-1) and a (meth)acrylic acid ester monomer unit (a1-2), the content of the (meth)acrylic acid monomer unit (a1-1) is preferably 2% to 30% by mass, and the content of the (meth)acrylic acid ester monomer unit (a1-2) is preferably 0% to 20% by mass, relative to the total amount of the styrene-unsaturated carboxylic acid resin (A). The content of the (meth)acrylic acid monomer unit (a1-1) is more preferably 3% to 20% by mass, and the content of the (meth)acrylic acid ester monomer unit (a1-2) is more preferably 1% to 17% by mass. The content of the (meth)acrylic acid monomer unit (a1-1) is further preferably 3.4% to 4.5% by mass. % to 25% by mass, and the content of the (meth)acrylic acid ester monomer unit (a1-2) is 3% to 15% by mass, more preferably the content of the (meth)acrylic acid monomer unit (a1-1) is 6% to 14% by mass, and the content of the (meth)acrylic acid ester monomer unit (a1-2) is 4% to 10% by mass, more preferably the content of the (meth)acrylic acid monomer unit (a1-1) is 9% to 12.5% ​​by mass, and the content of the (meth)acrylic acid ester monomer unit (a1-2) is 4.5% to 7.1% by mass, and most preferably the content of the (meth)acrylic acid monomer unit (a1-1) is 10.5% to 12.5% ​​by mass, and the content of the (meth)acrylic acid ester monomer unit (a1-2) is 4.5% to 7.1% by mass. By suppressing the content of the (meth)acrylic acid ester monomer unit (a1-2) to 20% by mass or less, a resin composition having excellent fluidity during molding can be obtained. In particular, by making the content of the (meth)acrylic acid monomer unit 9% by mass or more, more preferably 10.3% by mass or more, and even more preferably 10.5% by mass or more, a resin composition having excellent heat resistance can be obtained.

[0079] When the styrene-unsaturated carboxylic acid resin (A) is a terpolymer obtained by copolymerizing a styrene monomer (1), a (meth)acrylic acid monomer unit (a1-1) and a (meth)acrylic acid ester monomer unit (a1-2), the content of the (meth)acrylic acid monomer unit (a1-1) is 10.5% to 12.5% ​​by mass, the content of the (meth)acrylic acid ester monomer unit (a1-2) is 4.5% to 7.1% by mass, and the (meth)acrylic acid ester monomer unit (a1-2) is methyl methacrylate. Thus, a styrene resin composition having excellent balance among moldability, heat resistance, light resistance, oil resistance and surface hardness can be obtained.

[0080] <Other Monomers (a2)>

[0081] The styrene-unsaturated carboxylic acid resin (A) in the present embodiment may further have other monomer units (a2) in addition to 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)).

[0082] That is, in the present embodiment, the other monomer unit (a2) can be copolymerized with monomers other than the two monomers shown above without particular limitation as long as it is copolymerizable with the styrene monomer (1) and the unsaturated carboxylic acid monomer unit (a1) (including the (meth)acrylic acid monomer unit (a1-1) and / or the (meth)acrylic acid ester monomer unit (a1-2)) within a range not impairing the effects of the invention.

[0083] For example, 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 N-substituted maleimide.

[0084] In the present embodiment, when the styrene-unsaturated carboxylic acid resin (A) has other monomers (a2), the content of the other monomers (a2) relative to the total amount of the styrene-unsaturated carboxylic acid resin (A) is preferably 12% by mass or less, more preferably 5% by mass or less, further preferably 2% by mass or less, further preferably 1% by mass or less, and further preferably 0.5% by mass or less.

[0085] <Characteristics of Styrene-Unsaturated Carboxylic Acid Resin (A)>

[0086] The contents of the styrene monomer units (1), the unsaturated carboxylic acid monomer units (a1) (including (meth)acrylic acid monomer units (a1-1) and (meth)acrylic acid ester monomer units (a1-2)) and other monomer units (a2) in the styrene-unsaturated carboxylic acid resin (A) in the present embodiment can be quantified using a calibration curve prepared from resins whose monomer units are known using thermal decomposition GC / MS.

[0087] The melt flow rate of the styrene-unsaturated carboxylic acid resin (A) in the present embodiment at 200°C is preferably in the range of 0.3 to 3.0, more preferably in the range of 0.4 to 2.5, further preferably in the range of 0.5 to 2.0, further preferably in the range of 0.5 to 1.8, further preferably in the range of 0.5 to 1.1, and further preferably in the range of 0.5 to 1.0. When the above melt flow rate is 0.3 or more, it is preferred from the viewpoint of fluidity, and when the above melt flow rate is 3.0 or less, it is preferred from the viewpoint of mechanical strength of the resin. In the present disclosure, the melt flow rate is a value measured at 200°C and a load of 5 kg (49 N) in accordance with ISO1133.

[0088] The weight average molecular weight (Mw) of the styrene-unsaturated carboxylic acid resin (A) in the present embodiment is preferably 100,000 to 400,000, more preferably 120,000 to 320,000, further preferably 140,000 to 280,000, further 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 practicality and a 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 standards.

[0089] The number average molecular weight (Mn) of the styrene-unsaturated carboxylic acid-based resin (A) of the present embodiment is preferably 40,000 to 150,000, more preferably 50,000 to 120,000, and even more preferably 60,000 to 100,000.

[0090] The Z average molecular weight (Mz) of the styrene-unsaturated carboxylic acid-based resin (A) of the present embodiment is preferably 200,000 to 800,000, more preferably 250,000 to 500,000, and even more preferably 300,000 to 450,000.

[0091] The Vicat softening temperature of the styrene-unsaturated carboxylic acid resin (A) in the present embodiment is preferably 105°C to 140°C, more preferably 107°C to 135°C, further preferably 108°C to 130°C, further preferably 115°C to 127°C, further preferably 120°C to 125°C, and further preferably 121°C to 125°C. When the Vicat softening temperature of the styrene-unsaturated carboxylic acid resin (A) is 105°C or higher, the heat resistance of the composition can be improved. When the Vicat softening temperature of the styrene-unsaturated carboxylic acid resin (A) is 140°C or lower, it is easy to mix with the (meth) acrylic resin (B). In particular, when the Vicat softening temperature of the styrene-unsaturated carboxylic acid resin (A) is 120°C or higher, a styrene resin composition having excellent heat resistance can be obtained. The Vicat softening temperature in this specification is measured in accordance with ISO306 under the conditions of a load of 5 kg and a heating rate of 50°C / hour.

[0092] <Method for producing styrene-unsaturated carboxylic acid resin (A)>

[0093] Hereinafter, the method for producing the styrene-unsaturated carboxylic acid resin (A) according to the present embodiment will be described.

[0094] The method for producing the styrene-unsaturated carboxylic acid resin (A) of the present embodiment preferably includes the following steps: a step of mixing a styrene monomer (1), an unsaturated carboxylic acid monomer (a1) ((meth)acrylic acid monomer unit (a1-1) and / or a (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 generate a reaction product; and a step of recovering the reaction product.

[0095] The polymerization method of the styrene-unsaturated carboxylic acid resin (A) is not particularly limited, and for example, a radical polymerization method can be preferably used, and among them, a bulk polymerization method or a solution polymerization method is preferably used.

[0096] Specifically, the polymerization method preferably mainly comprises the following steps: a polymerization step of polymerizing a polymerization raw material (monomer component); and a devolatilization step of removing volatile components such as unreacted monomers and a polymerization solvent from the polymerization product.

[0097] In the present embodiment, when the polymerization raw material is polymerized to obtain the styrene-unsaturated carboxylic acid resin (A), a polymerization initiator is typically contained in the polymerization raw material composition. Examples of the polymerization initiator include: organic peroxides such as peroxyketals such as 2,2-bis(tert-butylperoxy)butane, 1,1-bis(tert-butylperoxy)cyclohexane, and 4,4-bis(tert-butylperoxy)valerate; dialkyl peroxides such as di-tert-butyl peroxide, tert-butylcumyl peroxide, and dicumyl peroxide; diacyl peroxides such as acetyl peroxide and isobutyryl peroxide; peroxydicarbonates such as diisopropyl peroxydicarbonate; peroxyesters such as tert-butyl peroxyacetate; ketone peroxides such as acetylacetone peroxide; hydroperoxides such as tert-butyl hydroperoxide, etc. Among them, 1,1-bis(tert-butylperoxy)cyclohexane is preferred from the viewpoint of decomposition rate and polymerization rate.

[0098] In the present embodiment, a chain transfer agent may be used as needed during the polymerization of the styrene-unsaturated carboxylic acid resin (A). Examples of the chain transfer agent include α-methylstyrene linear dimer, n-dodecyl mercaptan, tert-dodecyl mercaptan, and n-octyl mercaptan.

[0099] As a polymerization method of the styrene-unsaturated carboxylic acid resin (A), solution polymerization using a polymerization solvent may be used. As the polymerization solvent, aromatic solvents such as toluene, ethylbenzene, propylbenzene, and butylbenzene are preferred, 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 needed may also be used.

[0100] In the present embodiment, the polymerization solvent is preferably used in an amount within a range of 3 to 35 parts by mass, more preferably within a range of 5 to 30 parts by mass, relative to 100 parts by mass of all monomers constituting the styrene-unsaturated carboxylic acid resin (A). When the polymerization solvent exceeds 35 parts by mass relative to 100 parts by mass of the above-mentioned total monomers, the polymerization rate decreases, and the molecular weight of the resulting resin also decreases, so there is a tendency for the mechanical strength of the resin to decrease. In addition, when the polymerization solvent is less than 3 parts by mass, it may be difficult to control heat removal during polymerization. From the perspective of easy quality homogenization and polymerization temperature control, it is preferred to add the polymerization solvent in a ratio of 3 to 35 parts by mass relative to 100 parts by mass of all monomers.

[0101] When the monohydric alcohol (E) having 10 or more carbon atoms as an optional component of the styrene resin composition of the present embodiment is added from the polymerization system, the component (C) is preferably added at a ratio of 0.5 to 10% by mass based on 100% by mass of the entire polymerization solvent.

[0102] The device used in the polymerization process for obtaining the styrene-unsaturated carboxylic acid resin (A) in the present embodiment is not particularly limited, and can be appropriately selected according to the usual polymerization method of styrene resins. In the case of bulk polymerization, a polymerization device formed by connecting one or more completely mixed reactors can be used. In addition, there is no particular restriction on the devolatilization process. In the case of bulk polymerization, polymerization is carried out until the final unreacted monomer is preferably less than 50% by mass, more preferably less than 40% by mass. In order to remove volatile components such as the unreacted monomer, a devolatilization treatment is carried out using a known method. For example, a conventional devolatilization device such as a flash tank, a twin-screw devolatilizer, a thin film evaporator, an extruder, etc. can be used, preferably a devolatilization device with a small retention portion. It should be noted that the temperature of the devolatilization treatment is generally about 190°C to about 280°C, and from the viewpoint of suppressing decomposition, it is more preferably 190°C to 260°C. The pressure of the devolatilization treatment is usually about 0.13 kPa to about 4.0 kPa, preferably 0.13 kPa to 3.0 kPa, and more preferably 0.13 kPa to 2.0 kPa. As the devolatilization method, for example, a method of removing volatile components by reducing pressure under heating and a method of removing volatile components by an extruder designed for the purpose of removing volatile components are preferred.

[0103] "(Meth)acrylic resin (B)"

[0104] The styrene resin composition of the present embodiment contains 0 mass % or more and 90 mass % or less of a (meth)acrylic resin (B) (also referred to simply as resin (B)) relative to the total amount of the styrene resin composition. In addition, the (meth)acrylic resin (B) has an unsaturated carboxylic acid monomer unit (b1). By containing a predetermined amount of the (meth)acrylic resin (B), the oil resistance and mechanical strength of the entire styrene resin composition can be improved.

[0105] In addition, the (meth)acrylic resin (B) in this specification is a general term for synthetic resins containing 50% by mass or more of the unsaturated carboxylic acid monomer units (b1) based on the whole (meth)acrylic resin (B).

[0106] 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.

[0107] The content of the (meth)acrylic resin (B) is 0% by mass or more and 90% by mass or less relative to the total amount (100% by mass) of the styrene resin composition. The lower limit of the content of the (meth)acrylic resin (B) is preferably 0% by mass or more, greater 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, greater 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. 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. When the content of the (meth)acrylic resin (B) is greater than 0% by mass and less than or equal to 90% by mass, the decrease in heat resistance improved by the styrene-unsaturated carboxylic acid resin (A) can be suppressed. In particular, when the content of the (meth)acrylic resin (B) is greater than 20% by mass and less than or equal to 53% by mass, a styrene resin composition having an excellent balance between heat resistance and oil resistance can be obtained.

[0108] In addition, especially when emphasis is placed on the heat resistance, moldability and low water absorption of the resin, the content of the (meth)acrylic resin (B) is 0% to 30% by mass, preferably 0% to 20% by mass, more preferably 0% to 15% by mass, further preferably 0% to 10% by mass, and further preferably 0% to 5% by mass, relative to the total amount (100% by mass) of the styrene resin composition.

[0109] The unsaturated carboxylic acid monomer unit (b1) constituting the (meth)acrylic resin (B) of the present embodiment is preferably at least one repeating unit selected from the group consisting of a (meth)acrylic acid monomer unit (b1-1) and a (meth)acrylic acid ester monomer unit (b1-2). Therefore, the unsaturated carboxylic acid monomer unit (b1) includes a (meth)acrylic acid monomer unit (b1-1) and a (meth)acrylic acid ester monomer unit (b1-2).

[0110] The (meth)acrylic resin (B) is particularly preferably a copolymer having a methacrylate monomer unit and an acrylate monomer unit, because this can achieve effects of improving oil resistance and mechanical strength, and can also achieve resistance to thermal decomposition.

[0111] <(Meth)acrylic acid monomer (b1-1)>

[0112] In the present embodiment, examples of the (meth)acrylic acid monomer (b1-1) include acrylic acid and methacrylic acid.

[0113] <(Meth)acrylate monomer (b1-2)>

[0114] The (meth)acrylic acid ester monomer unit (b1) constituting the (meth)acrylic resin (B) of the present embodiment includes a methacrylic acid ester monomer unit and an acrylate monomer unit. In addition, 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, stearyl methacrylate, etc., and methyl acrylate, n-butyl acrylate, methyl methacrylate, 2-ethylhexyl methacrylate, and n-octyl methacrylate are preferred from the perspective of industrial availability and low cost. The (meth)acrylic acid ester monomer (b1-2) can be used alone or in combination, and preferably two (meth)acrylic acid ester monomers are combined.

[0115] 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 properties, a copolymer obtained by copolymerizing a methacrylic ester type and an acrylate type among the monomer units listed above is preferred, and a methyl methacrylate-methyl acrylate copolymer is more preferred.

[0116] <Preferred Embodiment of (Meth)Acrylic Resin (B)>

[0117] The preferred (meth)acrylic resin (B) of the present embodiment is preferably a binary copolymer or a ternary copolymer, preferably a methacrylate-acrylate copolymer obtained by copolymerizing a methacrylate species (methacrylate monomer unit) and an acrylate species (acrylate monomer unit), and preferably a copolymer containing 0.1% by mass to 25% by mass of acrylate monomer units relative to the total amount of the methacrylate-acrylate copolymer, more preferably a copolymer containing 0.5% by mass to 17% by mass of acrylate monomer units, further preferably a copolymer containing 1.0% by mass to 7.0% by mass of acrylate monomer units, further preferably a copolymer containing 1.2% by mass to 4.5% by mass of acrylate monomer units, and most preferably a copolymer containing 1.5% by mass to 3.0% by mass of acrylate monomer units.

[0118] The preferred (meth)acrylic resin (B) of the present embodiment is more preferably a methyl methacrylate-methyl acrylate copolymer, and a copolymer containing 0.5% to 17% by mass of methyl acrylate monomer units relative to the total amount of the copolymer, and more preferably a copolymer containing 1.0% to 5.0% by mass of methyl acrylate monomer units. This can more effectively suppress the decrease in heat resistance improved by the styrene-unsaturated carboxylic acid resin (A).

[0119] 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 54% by mass or more, more preferably 64% by mass or more, further preferably 71% by mass or more, further preferably 86% by mass or more, and most preferably 91% by mass or more, relative to the total amount of the (meth)acrylic resin (B). When the content of the methacrylic acid ester monomer (b1-2) is within the range of 55.0% by mass to 100% by mass, it can withstand kneading, extrusion and molding processing 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 the (meth)acrylic acid ester monomer (b1-2), methyl acrylate or methyl methacrylate is preferred from the aspects of heat resistance, industrial availability and low cost.

[0120] 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% by mass or less, more preferably 97% by mass or less, further preferably 91% by mass or less, further preferably 86% by mass or less, and most preferably 81% by mass or less, relative to the total amount of the (meth)acrylic resin (B).

[0121] In the (meth)acrylic resin (B) of the present embodiment, the upper limit of the content of the (meth)acrylic monomer unit (b1-1) in the (meth)acrylic resin (B) is preferably 15% by mass or less, more preferably 10% by mass or less, further preferably 5% by mass or less, further preferably 3% by mass or less, and most preferably 2% by mass or less, relative to the total amount of the (meth)acrylic resin (B). The lower limit of the content of the (meth)acrylic 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, further preferably 0.7% by mass or more, further preferably 1.0% by mass or more, and most preferably 1.5% by mass or more. The above upper and lower limits may be arbitrarily combined.

[0122] <Other Monomers (b2)>

[0123] The (meth)acrylic resin (B) of the present embodiment may further have other monomer units (b2) in addition to the above-mentioned unsaturated carboxylic acid monomer units (b1) (for example, (meth)acrylic acid monomers (b1-1) and / or (meth)acrylic acid ester monomer units (b1-2)). That is, as long as the other monomer units (b2) can be copolymerized with the unsaturated carboxylic acid monomer units (b1), they can be copolymerized with monomers other than the above-mentioned monomers without particular restrictions within the scope that does not impair the effects of the invention. For example, as other monomers (b2) other than the above-mentioned monomers, styrene, maleic anhydride, maleic acid, fumaric acid, itaconic acid, dimethyl maleate, dimethyl fumarate, diethyl fumarate, ethyl fumarate, maleimide, and N-substituted maleimide can be cited.

[0124] In the present embodiment, the content of other monomer units (b2) is preferably 0% by mass to 30% by mass, more preferably 0% by mass to 20% by mass, further preferably 0% by mass to 15% by mass, and further preferably 0% by mass to 7% by mass, relative to the total amount of the (meth)acrylic resin (B).

[0125] The upper limit of the weight average molecular weight (Mw) of the (meth)acrylic resin (B) is preferably 8,000,000 or less, 6,000,000 or less, 5,000,000 or less, 3,000,000 or less, 2,000,000 or less, 1,000,000 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 the order of standard polystyrene conversion by the GPC method described below, 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 the order of standard polystyrene conversion. The weight average molecular weight (Mw) of the (meth)acrylic resin (B) may be arbitrarily combined with the above-mentioned upper limit and lower limit. In particular, when the weight average molecular weight (Mw) of the (meth)acrylic resin (B) is 70,000 or more, a resin composition having excellent strength can be provided. When the weight average molecular weight (Mw) of the (meth)acrylic resin (B) is 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. Using the composition, a molded product with good appearance can be obtained. In addition, the viscosity of the resin composition can be reduced, so that a resin composition with good injection molding cycle can be obtained.

[0126] 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 in the range of 25,000 to 300,000, and further preferably in the range of 30,000 to 120,000, calculated in terms of standard polystyrene by the GPC method described below.

[0127] The weight average molecular weight (Mz) of the (meth)acrylic resin (B) is preferably within a range of 80,000 to 10,000,000, more preferably within a range of 90,000 to 800,000, and even more preferably within a range of 100,000 to 300,000, as calculated by the GPC method described below in terms of standard polystyrene.

[0128] The dispersion degree (Mw / Mn) of the (meth)acrylic resin (B) is preferably in the range of 1.1 to 6.0, more preferably in the range of 1.3 to 4.0, and even more preferably in the range of 1.5 to 3.7, as calculated in terms of standard polystyrene by the GPC method described below. In particular, when the dispersion degree (Mw / Mn) of the (meth)acrylic resin (B) is in the range of 1.5 to 3.7, a styrene resin composition having an excellent balance between moldability and strength can be obtained.

[0129] It should be noted that the (meth)acrylic resin (B) of the present embodiment may contain a high molecular weight component having a molecular weight of 1,000,000 or more. The high molecular weight component having a molecular weight of 1,000,000 or more includes an unsaturated carboxylic acid monomer (b1), and the ratio of the (meth)acrylic resin (B) having a high molecular weight component having a molecular weight of 1,000,000 or more to the (meth)acrylic resin (B) contained in the styrene resin composition is preferably 1.0% by mass or less relative to the total amount of the styrene resin composition.

[0130] It should be noted that as a method for controlling the high molecular weight component having a molecular weight of 1,000,000 or more in the (meth)acrylic resin (B) to be 1.0% by mass or less, when the unsaturated carboxylic acid monomer (b1) is subjected to free radical polymerization, 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, and the like can be controlled.

[0131] As described above, the (meth)acrylic resin (B) of the present embodiment preferably contains 0.0 mass % or more and 1.0 mass % or less of a high molecular weight component having a molecular weight of 1,000,000 or more based on the total amount of the styrene resin composition, and in particular, the weight average molecular weight (Mw) of the (meth)acrylic resin (B) as a whole is preferably 70,000 to 300,000.

[0132] <(Meth)acrylic acid monomer or (meth)acrylate monomer in styrene resin composition>

[0133] In the present embodiment, relative to the total amount (100% by mass) of the styrene resin composition, the content of all (meth) acrylic acid monomer units contained in the styrene resin composition is preferably 1% to 20% by mass, preferably in the range of 2% to 15% by mass, more preferably in the range of 3% to 10% by mass, and further preferably in the range of 4% to 8% by mass. When the content of the (meth) acrylic acid monomer in the resin composition as a whole is within the above range, the effect of improving heat resistance can be fully obtained. In addition, especially when the balance between heat resistance and moldability is emphasized, relative to the total amount (100% by mass) of the styrene resin composition, the content of all (meth) acrylic acid monomer units contained in the styrene resin composition is preferably 7% to 20% by mass, preferably 8% to 18% by mass, more preferably 10% to 15% by mass, and further preferably 10.3% to 12.5% ​​by mass.

[0134] The above-mentioned content of all (meth)acrylic monomers indicates the total amount of (meth)acrylic monomer units present in the styrene resin composition, and therefore the contents of the (meth)acrylic monomer units in the resin (A), the resin (B) and the optionally added resin are also converted.

[0135] In the present embodiment, relative to the total amount (100% by mass) of the styrene resin composition, the content of all (meth) acrylic acid ester monomer units contained in the styrene resin composition is preferably 6% to 55% by mass, preferably in the range of 10% to 50% by mass, more preferably in the range of 14% to 45% by mass, further preferably in the range of 16% to 40% by mass, and further preferably in the range of 20% to 37% by mass. When the content of the (meth) acrylic acid ester monomer in the composition as a whole is within the above range, the effect of improving oil resistance and strength can be fully obtained. In addition, especially when the moldability and low water absorption of the resin are emphasized, relative to the total amount (100% by mass) of the styrene resin composition, the content of all (meth) acrylic acid ester monomer units contained in the styrene resin composition is preferably 0% to 20% by mass, preferably 0% to 15% by mass, more preferably 0% to 10% by mass, more preferably 0% to 7% by mass, and more preferably 0% to 6% by mass.

[0136] The above-mentioned content of all (meth)acrylate monomers indicates the total amount of (meth)acrylate monomer units present in the styrene resin composition, and therefore the contents of the (meth)acrylate monomer units in the resin (A), the resin (B) and the optionally added resin are also converted.

[0137] 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 effectively obtained at the same time, and as a result, a styrene-based resin composition having excellent heat resistance and oil resistance and a sheet obtained by molding the composition can be obtained.

[0138] <Method for producing (meth)acrylic resin (B)>

[0139] The (meth)acrylic resin (B) of the present embodiment is not particularly limited in its production method, and can be produced by bulk polymerization of a (meth)acrylic acid ester monomer and other monomers as required, solution polymerization by adding a solvent, suspension polymerization by dispersing an organic phase in water using a suspending agent, emulsion polymerization, or the like.

[0140] "Light stabilizer (C)"

[0141] The light stabilizer (C) of the present embodiment has no ultraviolet absorption ability by itself, but can have the following function: capture the light free radicals generated by the styrene resin composition absorbing ultraviolet rays, make them harmless, thereby preventing the degradation or coloration of the styrene resin composition caused by the free radicals. As the light stabilizer (C), a hindered amine compound is preferred, and hindered amine compounds such as secondary amine type, tertiary amine type, and N-alkoxy type can be mentioned. The light stabilizer (C) can be used alone or in combination of two or more. By using the ultraviolet absorber (D) described later, a higher light resistance effect can be obtained. In other words, the coloration and strength reduction of the styrene resin composition or its molded product after light exposure caused by long-term outdoor use can be suppressed. The light stabilizer (C) mainly functions on the resin surface where more light free radicals are generated. Therefore, in order to better exert the effect, a low molecular weight light stabilizer (C) is preferred. In order to prevent mold contamination caused by excessive bleeding, it is necessary to adjust to an appropriate molecular weight.

[0142] As the light stabilizer (C), among hindered amine compounds, secondary amine type is preferred from the viewpoint of weather resistance and initial color tone when added.

[0143] The content of the light stabilizer (C) of the present embodiment is 0% by mass to 2.0% by mass, preferably 0.001% by mass to 2.0% by mass, relative to the total amount of the styrene resin composition, and the upper limit is preferably 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 is preferably 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. The content of the light stabilizer (C) can be selected from any combination of the upper limit and the lower limit described above.

[0144] The light stabilizer (C) of the present embodiment is preferably a hindered amine compound. Examples of the hindered amine compound include bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, bis(1-undecyoxy-2,2,6,6-tetramethylpiperidin-4-yl) carbonate, butane-1,2,3,4-tetracarboxylic acid tetrakis(2,2,6,6-tetramethyl-4-piperidinyl) ester, bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, N,N'-bis(1-undecyloxy-2,2,6,6-tetramethylpiperidin-4-yl) carbonate, (2,2,6,6-tetramethylpiperidin-4-yl)hexane-1,6-diamine, butyl (3,5-di-tert-butyl-4-hydroxybenzyl) malonate bis (1,2,2,6,6-pentamethyl-4-piperidinyl) ester, N,N'-1,6-hexanediylbis (N- (2,2,6,6-tetramethylpiperidin-4-yl) formamide), etc. Specific product names include: ADK manufactured by ADEKA Corporation STAB LA-52, ADK STAB LA-57, ADK STAB LA-63P, ADK STAB LA-68, ADKSTAB LA-72, ADK STAB LA-77Y, ADK STAB LA-77G, ADK STAB LA-81; JF-90G, JF-95 manufactured by Chengbei Chemical Co., Ltd.; Chimassorb 2020FDL, Chimassorb 944FDL, Tinuvin622SF manufactured by BASF Japan; Uvinul 4050FF manufactured by BASF Japan, etc.

[0145] "Ultraviolet light absorber (D)"

[0146] The ultraviolet absorber (D) of this embodiment can have the following functions: replace the styrene resin composition and absorb the ultraviolet light absorbed by the styrene resin composition, convert it into heat energy and chemical energy, thereby inhibiting the generation of photo free radicals caused by the ultraviolet absorption of the styrene resin composition, and inhibiting the degradation or coloring of the resin. As the ultraviolet absorber (D), it is preferably a compound having two or more aromatic rings and one or more aromatic rings having a phenolic hydroxyl group, and the two or more aromatic rings are bonded by a connecting group containing an atom having an unpaired electron (oxygen atom, nitrogen atom, sulfur atom, phosphorus atom, etc.). When the ultraviolet absorber (D) is this compound, it can have a chemical structure that absorbs light and becomes an excited state and then converts it into chemical energy. As the ultraviolet absorber (D) of this embodiment, for example, benzotriazole compounds, triazine compounds, benzophenone compounds, benzoate compounds, cyanoacrylate compounds, oxalylanilide compounds, malonic acid ester compounds, formamidine compounds, salicylate compounds, etc. can be cited. These ultraviolet absorbers (D) can be used alone or in combination of two or more. By using the aforementioned light stabilizer (C) and ultraviolet absorber (D) together, a higher light resistance effect can be obtained. In other words, the coloration and strength reduction of the styrene resin composition after exposure can be suppressed. In addition, it is preferred that the ultraviolet absorber (D) can replace and absorb the ultraviolet wavelength (250nm to 350nm) that the resin added to the styrene resin composition easily absorbs.

[0147] As the preferred ultraviolet absorber (D) of the present embodiment, for example, one or more selected from the group consisting of benzotriazole compounds, triazine compounds, benzophenone compounds, benzoate compounds, cyanoacrylate compounds, malonate compounds, and oxalanilide compounds are more preferred.

[0148] Specifically, the preferred ultraviolet absorber (D) of the present embodiment is preferably one or two or more compounds selected from the group consisting of compounds represented by the following general formulae (d) and (d′).

[0149]

[0150] (In the above general formula (d), M di Each independently represents an aromatic group having a valency of one or more, 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 1represents an alkyl group having 1 to 15 carbon atoms or an aralkyl group having 7 to 25 carbon atoms, wherein -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 heterocyclic ring (such as a benzotriazole ring)), d1 represents an integer of 0 to 4, and d2 represents an integer of 1 to 4. It should be noted that in the above general formula (d), M di With L di The connected wavy lines indicate that there are more than one single bond or more chemical bonds. It should be noted that when d1 is 0, it means that there is no substitution. )

[0151]

[0152] (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 1 to 15 carbon atoms, or an aralkyl group having 7 to 25 carbon atoms, wherein -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 heterocyclic ring (e.g., a benzotriazole ring)), and 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 1 to 15 carbon atoms, or an aralkyl group having 7 to 25 carbon atoms, wherein -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 heterocyclic ring (such as a benzotriazole ring)), and d5 represents an integer of 0 to 4. When d5 is 2 or more, R 8 They may be the same or different from each other.)

[0153] In the above general formula (d), M di Each independently represents unsubstituted or one or more hydrogen atoms may be substituted by R 2 The substituted monovalent or higher aromatic group is preferably unsubstituted or one or more hydrogen atoms may be substituted by a substituent R 2 The substituted monovalent or higher and tetravalent or lower aromatic ring is more preferably a group represented by the following formula (I) or (II).

[0154]

[0155] (In the above formula (I) or (II), R 2Each independently represents a halogen atom, a hydroxyl group, a cyano group or an alkyl group having 1 to 15 carbon atoms, wherein -CH2- in the alkyl group may be replaced by -O- or -C(=O)-, d3 represents an integer of 0 to 5, and d4 represents an integer of 0 to 4.

[0156] The above substituent R 2 represents a halogen atom, a hydroxyl group, a cyano group or an alkyl group having 1 to 15 carbon atoms, wherein -CH2- in the alkyl group may be replaced by -O- or -C(=O)-.

[0157] In the above general formula (d), L di Each independently represents a divalent to pentavalent group, and specifically, 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).

[0158]

[0159] In the general formula (d), d1 is an integer of 0 or more and 4 or less, and is preferably 0, 1, 2 or 3.

[0160] In the above general formula (d), d2 and L di The bonding (=valence) of di is a divalent group. Similarly, when d2 is 2, L di is a trivalent group. When d2 is 3, L di is a tetravalent group. When d2 is 4, L di is a pentavalent group. Therefore, L di The number of bonds -1 gives d2.

[0161] In the above general formula (d), R 1 represents an alkyl group having 1 to 15 carbon atoms, wherein -CH2- in the alkyl group 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 having an ester bond. In addition, when d1 is an integer greater than 2, the presence of multiple R 1 They may be the same as or different from each other.

[0162] As one embodiment of a preferred ultraviolet absorber (D) according to the present embodiment, specifically, a compound represented by the following general formula (d) is preferred.

[0163] The compound represented by the 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).

[0164]

[0165] (In the above general formula (d-1), M 1 is a group represented by the above formula (II).

[0166] (In the above general formula (d-2), M 2 and M 3 is a group represented by the above formula (I), L 1 is -N= or a group represented by the above formula (III).

[0167] (In the above general formula (d-3), M 4 is a group represented by the above formula (I), L 2 is -C(=O)-, -C(=O)-O- or -OC(=O)-. )

[0168] (In the above general formula (d-4), M 5 represents a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, an alkyl group having 1 to 15 carbon atoms, an alkenyl group having 1 to 15 carbon atoms, or an aralkyl group having 7 to 25 carbon atoms, and is preferably a group represented by the above formula (I), R d4 represents an alkyl group having 1 to 10 carbon atoms, L 3 is -NH-C(=O)-C(=O)-NH-. )

[0169] It should be noted that, in the above general formulas (d-1) to (d-4), “R 1 and d1" and "R 1 It has the same meaning as "d1".

[0170] As the compound represented by the general formula (d-1), a compound represented by the following general formula (d-1.1) or (d-1.2) is preferred.

[0171]

[0172]

[0173] (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, wherein -CH2- in the alkyl group may be replaced by -O- or -C(=O)-, and R 1and d1 and "R" in the above general formula (d) 1 and d1" have the same meaning. In addition, 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, wherein -CH2- in the alkyl group may be replaced by -O- or -C(=O)-, and R 4 Each independently represents a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or an alkoxy group having 1 to 15 carbon atoms, and m represents an integer of 1 to 5.

[0174] As the compound represented by the above general formula (d-2), a compound represented by the following general formula (d-2.1) is preferred.

[0175]

[0176] (In the above general formula (d-2.1), M 2 and M 3 is a group represented by the above formula (I), R 1 and d1 and "R" in the above general formula (d) 1 This has the same meaning as "d1".)

[0177] As the compound represented by the above general formula (d-3), a compound represented by the following general formula (d-3.1) is preferred.

[0178]

[0179] (In the above general formula (d-3.1), M 4 is a group represented by the above formula (I), R 1 and d1 and "R" in the above general formula (d) 1 This has the same meaning as "d1".)

[0180] As a preferable ultraviolet absorber (D) of this embodiment, specifically, the compound represented by the following general formula (d-4.1) can also be used suitably.

[0181]

[0182] (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, an alkenyl group having 1 to 15 carbon atoms, or an aralkyl group having 7 to 25 carbon atoms, wherein -CH2- in the alkyl group may be replaced by -O- or -C(=O)-.

[0183] Among the compounds represented by the general formula (d-4.1), R 10 The aralkyl group is preferably an aralkyl group having 7 to 25 carbon atoms, more preferably an aralkyl group having 7 to 20 carbon atoms, and even more preferably an aralkyl group having 7 to 18 carbon atoms.

[0184] As another preferable ultraviolet absorber (D) of the present embodiment, specifically, a compound represented by the following general formula (d′) can also be suitably used.

[0185]

[0186] (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 1 to 15 carbon atoms, or an aralkyl group having 7 to 25 carbon atoms, wherein -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 heterocyclic ring (e.g., a benzotriazole ring)), and 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 1 to 15 carbon atoms, or an aralkyl group having 7 to 25 carbon atoms, wherein -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 heterocyclic ring (such as a benzotriazole ring)), and d5 represents an integer of 0 to 4. When d5 is 2 or more, R 8 They may be the same or different from each other.)

[0187] In the above general formula (d'), R 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, an alkenyl group having 1 to 15 carbon atoms, or an aralkyl group having 7 to 25 carbon atoms, wherein -CH2- in the alkyl group may be replaced by -O- or -C(=O)-. From the viewpoint of stability, R 5 Particularly preferred is a phenyl group or a hydrogen atom.

[0188] In the above general formula (d'), with respect to R 6 and R 7 Preferred embodiments include a group represented by the following general formula (V) or a cyano group (—CN).

[0189]

[0190] (In the above general formula (V), R 9 represents a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, an alkyl group having 1 to 15 carbon atoms, an alkenyl group having 1 to 15 carbon atoms, or an aralkyl group having 7 to 25 carbon atoms, wherein -CH2- in the alkyl group may be replaced by -O- or -C(=O)-. In addition, -CH3 in the alkyl group may be replaced by -CN.)

[0191] In particular, from the viewpoint of compatibility and stability with styrene-based resins, in the above general formula (V), R 9 An alkyl group having 1 to 15 carbon atoms is preferred, an alkyl group having 1 to 10 carbon atoms is more preferred, an alkyl group having 1 to 5 carbon atoms is further preferred, an alkyl group having 1 to 3 carbon atoms is further preferred, and an alkyl group having 1 to 2 carbon atoms is particularly preferred.

[0192] Regarding R in the above general formula (d') 8 Preferred embodiments include: a group represented by the above general formula (V) or an alkyl group having 1 to 15 carbon atoms, wherein -CH2- in the alkyl group may be replaced by -O- or -C(=O)-.

[0193] In the above general formula (d'), R 8 The position of is preferably the para position on the benzene ring in the general formula (d').

[0194] In the above general formula (d′), d5 is more preferably 0 or 1 from the viewpoint of stability.

[0195] The content of the ultraviolet absorber (D) of the present embodiment is 0.001% by mass to 2.0% by mass relative to the total amount of the styrene resin composition, and the upper limit is preferably 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, and the lower limit is preferably 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. The content of the ultraviolet absorber (D) can be selected from any combination of the upper limit and the lower limit.

[0196] Examples of the benzotriazole compounds 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, and 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol. Specific product names include ADK STAB manufactured by ADEKA Corporation. LA-32, ADK STAB LA-36, ADK STAB LA-36RG; JF-77, JF-79, JF-80, JF-83, JF-832, JAST-500 manufactured by Chengbei Chemical Company; Tinuvin P, Tinuvin 234, Tinuvin 234FF, Tinuvin 326, Tinuvin 329, Tinuvin 360, etc. manufactured by BAST Japan.

[0197] Examples of the triazine compounds include 2-(4,6-diphenyl-1,3,5-triazine-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"-tris(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-octyloxy)-1,3,5-triazine, Specific product names include ADK STAB LA-46 and ADK STAB LA-F70 manufactured by ADEKA Corporation; Tinuvin 1577ED and Tinuvin 1600 manufactured by BAST Japan Co., Ltd.

[0198] Examples of the benzophenone compounds include 2-hydroxy-4-octyloxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,4-dihydroxybenzophenone, and 2,2',4,4'-tetrahydroxybenzophenone. Specific product names include ADK STAB 1413 manufactured by ADEKA; Chimassorb 81 and Chimassorb 81FL manufactured by BAST Japan.

[0199] Examples of the cyanoacrylate compounds include 2,2-bis{[(2-cyano-3,3-diphenylacryloyl)oxy]methyl}propane-1,3-diylbis(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.

[0200] Examples of the malonic acid ester compound include (4-methoxybenzylidene)malonate and tetraethyl 2,2′-(1,4-xylylenediyl)dimalonate. Specific examples include HOSTAVIN PR-25 GR and HOSTAVIN B-CAP manufactured by Clariant.

[0201] Examples of the oxalic anilide compound include N-(2-ethylphenyl)-N′-(2-ethoxyphenyl)oxalyl diamide, and specific examples include HOSTAVIN VSU P manufactured by Clariant.

[0202] In the present embodiment, two or more types of ultraviolet absorbers (D) may be used in combination. As a preferred embodiment, an ultraviolet absorber (D) that can effectively absorb the ultraviolet absorption peak attributed to the aromatic group of the styrene resin in the region where the ultraviolet absorption is sensitized due to light degradation (wavelength 250nm to 300nm) and an ultraviolet absorber (D) that can effectively absorb the ultraviolet region (wavelength 300nm to 400nm) that irradiates the most to the ground surface are used together. In the present embodiment, as a preferred embodiment of the ultraviolet absorber (D), it is particularly preferred to contain 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 an ultraviolet absorber (D) that can effectively absorb ultraviolet rays with a wavelength of 250nm to 300nm, a combination type ultraviolet absorber in which a benzotriazole ultraviolet absorber or a benzophenone ultraviolet absorber is combined with a triazine ultraviolet absorber is preferred.

[0203] In addition, when the initial color tone is particularly important, it is preferred to use a small amount of a malonic acid ester or oxalic acid anilide ultraviolet absorber, which is an ultraviolet absorber that absorbs little in the visible light region (wavelength 380 nm or more) and absorbs only in the ultraviolet region (near 250 nm to 350 nm), and a triazine ultraviolet absorber, which is an ultraviolet absorber that can effectively absorb ultraviolet rays with a wavelength of 250 nm to 300 nm. In addition, by using a malonic acid ester or oxalic acid anilide ultraviolet absorber in combination with a benzophenone compound or a cyanoacrylate compound that absorbs little in the visible light region and changes color little when added, a styrene resin composition with excellent initial color tone can be obtained.

[0204] In the present embodiment, when the initial color tone is emphasized, 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 (near 250 nm to 350 nm). As suitable ultraviolet absorbers (D), specifically, malonate compounds and oxalylanilide compounds that have absorption only near 250 nm to 350 nm are particularly preferred. In addition, as other suitable ultraviolet absorbers (D), benzophenone compounds and cyanoacrylate compounds that have little absorption in the visible light region and little color change when added can also be used.

[0205] In the present embodiment, as the ultraviolet absorber (D), an ultraviolet absorber (D) that can effectively absorb the ultraviolet absorption peak attributed to the aromatic group of the styrene resin in the region (wavelength 250nm to 300nm) where ultraviolet absorption is sensitized due to light degradation is effective. Specifically, as the ultraviolet absorber (D) that can effectively absorb ultraviolet rays with a wavelength of 250nm to 300nm, a triazine compound can be cited. When a triazine compound is used as the ultraviolet absorber (D), a sufficient effect can be obtained even if the addition amount is reduced, and discoloration of the resin when added can be reduced.

[0206] "Monohydric alcohol with 10 or more carbon atoms (E)"

[0207] The monohydric alcohol (E) having 10 or more carbon atoms (hereinafter, also referred to as alcohol (E)) in the present embodiment is an optional component of the styrene resin composition, and suppresses gelation of the styrene-unsaturated carboxylic acid resin (A) during molding, contributes to the improvement of the appearance of the styrene resin composition and the molded body containing the styrene resin composition, and also provides a demolding effect during injection molding. The content of the monohydric alcohol (E) having 10 or more carbon atoms is 0.01% by mass to 1.0% by mass, preferably 0.03% by mass to 0.8% by mass, more preferably 0.05% by mass to 0.6% by mass, and further preferably 0.07% by mass to 0.5% by mass, relative to the total amount (100% by mass) of the styrene resin composition. When the content of the monohydric alcohol (E) having 10 or more carbon atoms is 0.01% by mass or more, gelation of the styrene-unsaturated carboxylic acid resin (A) during molding can be suppressed, and when the content of the monohydric alcohol (E) having 10 or more carbon atoms is 1.0% by mass or less, a decrease in heat resistance and generation of odor can be suppressed. When the content of the monohydric alcohol (E) having 10 or more carbon atoms is 0.07% by mass to 0.5% by mass, a sufficient gel inhibition effect and a mold release effect can be obtained without particularly reducing heat resistance.

[0208] In addition, especially when the molded product has a complex shape and requires excellent mold release properties, the content of the monohydric alcohol (E) with a carbon number of 10 or more is preferably 0.1% by mass to 0.5% by mass, more preferably 0.1% by mass to 0.4% by mass, and more preferably 0.1% by mass to 0.3% by mass relative to the total amount of the styrene resin composition. By setting the content of the monohydric alcohol (E) with a carbon number of 10 or more to 0.1% by mass to 0.5% by mass, a styrene resin composition with a particularly high mold release effect can be obtained without reducing heat resistance. When the amount of the alcohol with a carbon number of 10 or more is less than 0.1% by mass, the mold release properties are easily reduced, especially for molded products with complex shapes. When the amount of the alcohol with a carbon number of 10 or more exceeds 0.5% by mass, there are concerns about reduced heat resistance and worsening mold contamination.

[0209] The monohydric alcohol (E) having 10 or more carbon atoms is an alcohol having 10 or more carbon atoms and containing one hydroxyl group. The carbon chain constituting the alcohol (E) may contain heteroatoms such as oxygen or nitrogen, and the carbon chain may contain bonds other than single bonds such as double bonds, triple bonds, ester bonds, and amide bonds. The number of carbon atoms is preferably 16 or more, more preferably 17 or more, and even more preferably 18 or more and 50 or less. The monohydric alcohol (E) having 10 or more carbon atoms may be contained in the styrene resin composition or a molded article containing the styrene resin composition. Therefore, the monohydric alcohol (E) having 10 or more carbon atoms may be present in (or added to) the polymerization solution used when polymerizing the styrene-unsaturated carboxylic acid resin (A) or the (meth)acrylic resin (B), thereby allowing the monohydric alcohol (E) to remain in the resin composition as the final product. Alternatively, the monohydric alcohol (E) may be added when kneading the styrene-unsaturated carboxylic acid resin (A) and the (meth)acrylic resin (B), and the mixture may be mixed in an extruder, thereby allowing the resin composition to contain the monohydric alcohol (E).

[0210] As the monohydric alcohol (E) having 10 or more carbon atoms, it is preferred that the carbon chain constituting the monohydric alcohol (E) does not contain a heteroatom and is composed only of an alkyl group from the viewpoint of molecular bond stability. Monohydric alcohols whose carbon chains are composed only of alkyl groups have excellent thermal stability and compatibility with styrene-based resins, and thus have an effect of suppressing mold contamination during molding. In addition, the number of carbon atoms in the alcohol is preferably 15 or more, more preferably 16 or more, further preferably 17 or more and 50 or less, and particularly preferably 18 or more and 30 or less.

[0211] In the present 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. When the boiling point of alcohol is lower than 260° C., volatility increases and there is a tendency to generate odor during molding.

[0212] The monohydric alcohol (E) having 10 or more carbon atoms is not particularly limited, and examples thereof include 1-hexadecanol, isohexadecanol, 1-octadecanol, 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-1-octanol, isooctadecanol, 1-isoeicosanol, 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.

[0213] The polyoxyethylene alkyl ethers are preferably compounds represented by the following general formula (2).

[0214]

[0215] (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 oxide additions, and X is an integer of 1 to 15.)

[0216] Specific product names of preferred alcohol (E) include “FINEOXOCOL 180” manufactured by Nissan Chemical Industries, Ltd., “KALCOL 8098” manufactured by Kao Corporation, and “EMULGEN 109P” manufactured by Kao Corporation.

[0217] "Release agent (F)"

[0218] As a preferred mode of this embodiment, the styrene resin composition preferably has a release agent (F). As a method of containing the release agent (F), it can be 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 granulating the styrene resin composition, or these two forms can be combined.

[0219] The content of the release agent (F) of the present embodiment is preferably 0.001% by mass to 2.0% by mass relative to the total amount (100% by mass) of the styrene resin composition, and as the upper limit, it 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. The lower limit is preferably in the order of 0.003 mass %, 0.005 mass %, 0.007 mass %, 0.009 mass %, 0.012 mass %, 0.031 mass %, 0.066 mass %, 0.090 mass %, 0.11 mass %, 0.16 mass %, 0.21 mass %, 0.26 mass %, and 0.31 mass %. When the content of the release agent (F) is in the range of 0.001 mass % to 2.0 mass %, a styrene resin composition having excellent releasability can be obtained, and when the content of the release agent (F) is in the range of 0.01 mass % to 0.8 mass %, a styrene resin composition having excellent balance between releasability and heat resistance can be obtained.

[0220] In addition, when the molded product has a complex shape and excellent mold release properties are required, a monohydric alcohol (E) having 10 or more carbon atoms is used as a mold release agent (F), and the content of the monohydric alcohol (E) having 10 or more carbon atoms is preferably 0.1% by mass to 0.5% by mass, more preferably 0.1% by mass to 0.4% by mass, and further preferably 0.1% by mass to 0.3% by mass relative to the total amount of the styrene resin composition. When the content of the monohydric alcohol (E) having 10 or more carbon atoms is 0.1% by mass to 0.5% by mass, a styrene resin composition having a particularly high mold release effect can be obtained without reducing heat resistance.

[0221] When the styrene 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% by mass to 2.0% by mass, more preferably 0.10% by mass to 1.5% by mass, more preferably 0.10% by mass to 1.0% by mass, more preferably 0.13% by mass to 1.0% by mass, and further preferably 0.17% by mass to 0.8% by mass, relative to the total amount (100% by mass) of the styrene resin composition. In particular, when the content of the internal lubricant (F1) is within the range of 0.13% by mass to 1.0% by mass, a styrene resin composition having excellent release properties and suppressed excessive bleeding can be obtained.

[0222] When the styrene resin composition of the present embodiment contains a release agent (F) as the external lubricant (F2), the content of the release agent as the external lubricant (F2) is preferably in the range of 0.005% by mass to 0.5% by mass, more preferably in the range of 0.007% by mass to 0.2% by mass, and further preferably in the range of 0.008% by mass to 0.1% by mass, relative to the total amount (100% by mass) of the styrene resin composition. In particular, when the content of the release agent as the external lubricant (F2) is in the range of 0.008% by mass to 0.1% by mass, a styrene resin composition having excellent mold release properties while suppressing mold contamination can be obtained.

[0223] Examples of the release agent (F) of the present embodiment include stearic acid, zinc stearate, calcium stearate, glycerin, glyceryl monostearate, glyceryl distearate, ethylene bisstearamide, stearamide, oleamide, erucamide, and hardened castor oil. From the viewpoint of the ability to impart release properties to the styrene resin, stearic acid, zinc stearate, and calcium stearate are preferred.

[0224] When glyceryl monostearate and / or glyceryl distearate is used as the release agent (F) of the present 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", "EXCELO-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 glyceryl monostearate or glyceryl distearate used as the release agent (F) is 0.01% to 0.5% by mass, more preferably 0.03% to 0.45% by mass, further preferably 0.05% to 0.4% by mass, further preferably 0.05% to 0.35% by mass, further preferably 0.08% to 0.30% by mass, further preferably 0.10% to 0.30% by mass, further preferably 0.10% to 0.25% by mass, relative to the total amount (100% by mass) of the styrene resin composition.

[0225] When 0.03% to 0.45% by mass of glyceryl monostearate or glyceryl distearate is contained based on the total amount (100% by mass) of the styrene-based resin composition, a styrene-based resin composition having particularly excellent releasability and initial color tone of the resin can be obtained.

[0226] “Other ingredients (additives)”

[0227] In the styrene resin composition of the present embodiment, in addition to the above-mentioned components, various additives commonly used in styrene resins can be added to achieve the known effects to prepare a styrene resin composition. Examples of the additives include stabilizers, higher fatty acid surfactants, antioxidants, plasticizers, anti-blocking agents, antistatic agents, anti-fogging agents, or 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, styrene-butadiene block copolymers, and reinforcing materials such as core-shell MBS resin particles can also be added within the range that does not damage the physical properties. There is no particular provision for the method of mixing the above-mentioned crosslinked body (G) or additives, for example, a method of adding and polymerizing during polymerization; or a method of pre-mixing the additives using a blender before melt-kneading after polymerization, and then melt-kneading using an extruder or Banbury mixer, etc.

[0228] In the present embodiment, when the crosslinked body (G) is used, the content of the crosslinked body (G) is preferably 3% by mass or less, more preferably 2% by mass or less, further preferably 1% by mass or less, further preferably 0.5% by mass or less, further preferably 0.1% by mass or less, further preferably 0.05% by mass or less, particularly preferably 0.01% by mass or less, and further preferably 0.001% by mass or less, relative to the total amount of the styrene resin composition. When the amount of the crosslinked body (G) added is reduced, the transparency is improved.

[0229] Examples of the crosslinked body (G) include, in addition to the above-mentioned reinforcing materials, crosslinked resin particles including a copolymer obtained by polymerizing one or two or more monomers selected from the group consisting of (meth)acrylate monomers, styrene monomers, and butadiene.

[0230] In particular, from the viewpoint of stability during processing and prevention of thermal degradation, examples of antioxidants include octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 4,6-bis(octylthiomethyl)-o-cresol, bis(3-tert-butyl-4-hydroxy-5-methylphenylpropionate)ethylenebis(oxyethylene)ester, 2,2'-dimethyl-2,2'-(2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diyl)propane-1 , 1'-diylbis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate], 2-{1-[2-hydroxy-3,5-bis(2-methylbutan-2-yl)phenyl]ethyl}-4,6-bis(2-methylbutan-2-yl)phenyl propionate, 2-tert-butyl-6-[(3-tert-butyl-2-hydroxy-5-methylphenyl)methyl]-4-methylphenyl acrylate (as a product name, for example, Irganox manufactured by BASF Japan Co., Ltd. 1076, Irganox 245; Sumilizer GA-80, Sumilizer GS, Sumilizer GM manufactured by Sumitomo Chemical Co., Ltd.) and other hindered phenol antioxidants; tris(2,4-di-tert-butylphenyl) 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-di(octadecyl-1-yl)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane (as product names, for example, Irgafos 168 manufactured by BASF Japan; ADK STAB PEP-36, ADK STAB TPP, ADK STAB 3010, ADK Phosphorus-containing antioxidants such as STABPEP-8) can be used. In addition, phosphorus-containing antioxidants having a hindered phenol skeleton such as 6-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-tert-butyldibenzo[d,f][1,3,2]dioxaphosphopepidine (as a product name, for example, Sumilizer GP manufactured by Sumitomo Chemical Co., Ltd.) can be used.

[0231] These stabilizers can be used alone or in combination of two or more and used appropriately. There is no particular restriction on the addition period, and it can be any process in the polymerization process or the devolatilization process. In addition, mechanical devices such as extruders and mixers can also be used to mix stabilizers in the product.

[0232] The (total) content of the antioxidant of the present embodiment is 0.001% to 1.0% by mass relative to the total amount of the styrene resin composition. The lower limit of the preferred range of the addition amount is 0.001% by mass or more, more preferably 0.005% by mass or more, more preferably 0.008% by mass or more, more preferably 0.01% by mass or more, more preferably 0.05% by mass or more, more preferably 0.08% by mass or more, more preferably 0.1% by mass or more, and more preferably 0.21% by mass or more. The upper limit of the preferred range of the addition amount is 1.0% by mass or less, more preferably 0.9% by mass or less, more preferably 0.8% by mass or less, more preferably 0.7% by mass or less, more preferably 0.6% by mass or less, more preferably 0.5% by mass or less, and more preferably 0.4% by mass or less. When the content of the antioxidant in the styrene resin composition increases, degradation and thermal degradation of the resin during processing are not likely to occur, but discoloration of the resin is likely to occur. In addition, when the content of the antioxidant is reduced, degradation during processing and thermal degradation are likely to occur, but discoloration of the resin is unlikely to occur.

[0233] The (total) content of the phenolic antioxidant of the present embodiment is 0.001% to 1.0% by mass relative to the total amount of the styrene resin composition. The lower limit of the preferred range of the amount of phenolic antioxidant added is 0.001% by mass or more, more preferably 0.005% by mass or more, more preferably 0.008% by mass or more, more preferably 0.01% by mass or more, more preferably 0.05% by mass or more, more preferably 0.08% by mass or more, more preferably 0.1% by mass or more, and more preferably 0.21% by mass or more. The upper limit of the preferred range of the amount added is 1.0% by mass or less, more preferably 0.9% by mass or less, more preferably 0.8% by mass or less, more preferably 0.7% by mass or less, more preferably 0.6% by mass or less, more preferably 0.5% by mass or less, and more preferably 0.4% by mass or less. When the content of the phenolic antioxidant in the styrene resin composition increases, degradation and thermal degradation of the resin during processing are not likely to occur, but discoloration of the resin is likely to occur. In addition, when the content of the antioxidant is reduced, degradation during processing and thermal degradation are likely to occur, but discoloration of the resin is unlikely to occur.

[0234] The (total) content of the phosphorus-containing antioxidant of the present embodiment is 0.001% to 1.0% by mass relative to the total amount of the styrene resin composition. The lower limit of the preferred range of the amount of the phosphorus-containing antioxidant added is 0.001% by mass or more, more preferably 0.005% by mass or more, more preferably 0.008% by mass or more, more preferably 0.01% by mass or more, more preferably 0.05% by mass or more, more preferably 0.08% by mass or more, more preferably 0.1% by mass or more, and more preferably 0.21% by mass or more. The upper limit of the preferred range of the amount added is 1.0% by mass or less, more preferably 0.9% by mass or less, more preferably 0.8% by mass or less, more preferably 0.7% by mass or less, more preferably 0.6% by mass or less, more preferably 0.5% by mass or less, and more preferably 0.4% by mass or less. When the content of the phosphorus-containing antioxidant in the styrene resin composition increases, degradation and thermal degradation of the resin during processing are not likely to occur, but discoloration of the resin is likely to occur. In addition, when the content of the antioxidant is reduced, degradation during processing and thermal degradation are likely to occur, but discoloration of the resin is unlikely to occur.

[0235] In the present embodiment, when a phenolic antioxidant and a phosphorus-containing antioxidant are used in combination, the molar ratio of the phenolic antioxidant to the phosphorus-containing antioxidant is phenolic antioxidant:phosphorus-containing antioxidant = 5:1 to 1:5, more preferably 4:1 to 1:4, further preferably 3:1 to 1:3, further preferably 2:1 to 1:3, further preferably 1:1 to 1:3, further preferably 1:1 to 1:2.8. The above-mentioned antioxidant mixing ratio can be particularly effective in preventing discoloration of the resin.

[0236] In the present embodiment, when 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) which is a phenolic antioxidant and can capture alkyl radicals generated by light or heat degradation and render them harmless is used in combination with a phosphorus-containing antioxidant, the thermal stability during processing can be particularly improved, and discoloration of the resin caused by heat degradation or the like can be suppressed.

[0237] In the present embodiment, among the phosphorus-containing antioxidants, Irgafos 168 (compound name: tris(2,4-di-tert-butylphenyl) phosphite) has a particularly excellent hydrolysis resistance effect and can be suitably used even in a water-absorbing resin and under high humidity conditions.

[0238] Among the phosphorus-containing 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, and ADK STAB PEP-8 (compound name: 3,9-di(octadec-1-yl)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane) have the characteristics of being highly effective in imparting thermal stability during processing and being less likely to discolor.

[0239] In the present embodiment, sulfur-containing antioxidants may be used, and examples thereof include dilauryl 3,3'-thiodipropionate, dimyristyl 3,3'-thiodipropionate, distearyl 3,3'-thiodipropionate, pentaerythritol tetrakis(3-laurylthiopropionate), ditridecyl 3,3'-thiodipropionate, and 2-mercaptobenzimidazole.

[0240] In this embodiment, a preferred mode when using an antioxidant is to use a phenolic antioxidant having a hindered phenol skeleton and a phosphorus-containing antioxidant having a phosphite structure in combination, the total content of the antioxidants is 0.1% to 0.5% by mass, and the molar ratio of the phenolic antioxidant to the phosphorus-containing antioxidant is phenolic antioxidant:phosphorus-containing antioxidant = 1:1 to 1:3. In the above case, a styrene resin composition having excellent initial color tone and thermal stability can be obtained.

[0241] In the present embodiment, the light stabilizer (C) is preferably a compound having a hindered amine skeleton, and the compound having a hindered amine skeleton has the following function: capturing light free radicals generated by the styrene resin composition absorbing ultraviolet rays and rendering them harmless, thereby preventing the degradation or coloring of the styrene resin composition caused by the free radicals. On the other hand, antioxidants are classified into phenolic antioxidants having a hindered phenol skeleton and phosphorus-containing antioxidants having a phosphite structure. Since it is difficult to strictly classify antioxidants and light stabilizers (C), in this specification, when calculating the content of light stabilizer (C) and / or antioxidant, for example, in the case of an antioxidant having both a hindered phenol skeleton and a phosphite structure, both the phenolic antioxidant and the phosphorus-containing antioxidant are counted and the added amount is calculated. In addition, in the case of both having a hindered amine skeleton and a hindered phenol skeleton, both the light stabilizer and the phenolic antioxidant are counted and the content is calculated.

[0242] [Physical properties of styrene resin composition]

[0243] The physical properties of the styrene-based resin composition in this embodiment will be described below.

[0244] <Vicat softening temperature>

[0245] In the present embodiment, the Vicat softening temperature of the styrene resin composition is preferably 105°C or higher, more preferably 110°C or higher, further preferably 115°C or higher, further preferably 118°C or higher, and further preferably 121°C or higher. When the Vicat softening temperature is 105°C or higher, a molded product that is not easily deformed by heat even in a car during the day can be obtained, and when the Vicat softening temperature is 110°C or higher, a molded product that is not easily deformed by heat even in a car during the day in summer can be obtained. As described later, the Vicat softening temperature can be measured according to ISO306 under the conditions of a load of 5 kg and a heating rate of 50°C / hour.

[0246] In the present embodiment, the surface scratch hardness of the styrene resin composition is preferably greater than or equal to H. The surface scratch hardness is measured in accordance with the scratch hardness (pencil method) described in JIS K 5600-5-4 under the conditions of a pencil lead tip load of 750 g, a pencil angle of 45 degrees, and a scratching speed of 0.5 mm / sec to 1.0 mm / sec.

[0247] When the surface scratch hardness of the styrene resin composition is H or more, when the molded article of the styrene resin composition is used for a transparent plate for vehicle use (for example, a transparent cover of a speedometer or a cover of a lighting device), breakage or scratching due to human hands or whitening due to oil stains can be suppressed.

[0248] <Melt mass flow rate>

[0249] In the present embodiment, the melt flow rate of the styrene resin composition at 200°C and a load of 5 kg is preferably in the range of 0.1 g / 10 min to 2.0 g / 10 min, more preferably 0.2 g / 10 min to 1.5 g / 10 min, further preferably 0.4 g / 10 min to 1.0 g / 10 min, and further preferably 0.5 g / 10 min to 1.0 g / 10 min. By having a melt flow rate of 0.3 g / 10 min or more, good moldability can be obtained, and by having a melt flow rate of 2.0 g / 10 min or less, a resin having excellent strength can be obtained. If the value of the melt mass flow rate is 0.5 g / 10 min to 1.0 g / 10 min, a resin having excellent balance between moldability and strength can be obtained.

[0250] <Conjugated Diene Monomer Unit Content>

[0251] The styrene resin composition of the present embodiment can contain rubbery polymers containing conjugated diene monomer units such as high impact polystyrene, MBS resin, ABS resin, styrene elastomer or core-shell butadiene rubber particles as needed. Moreover, in the present embodiment, relative to the entire styrene resin composition, the content of conjugated diene monomer units derived from high impact polystyrene, MBS resin, ABS resin, styrene elastomer, core-shell butadiene rubber particles, etc. added as needed is preferably 0 mass % to 25 mass %, more preferably 0 mass % to 10 mass %, more preferably 0.05 mass % to 7 mass %, further preferably 0.10 mass % to 5 mass %, and further preferably 0.20 mass % to 3 mass %. By the content of the conjugated diene monomer unit in the above-mentioned range, a composition with excellent balance of transparency and strength can be obtained.

[0252] <Amount of Styrene Component and Unsaturated Carboxylic Acid Component in Styrene Resin Composition>

[0253] The styrene resin composition in the present embodiment contains a styrene component and an unsaturated carboxylic acid component. The styrene component referred to herein is a general term for styrene monomer units contained in the styrene monomer units (1) and other monomers (b2).

[0254] 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, it is a general term for the unsaturated carboxylic acid monomer unit that can be included 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).

[0255] Regarding the styrene resin composition in the present embodiment, the content of the styrene component is preferably 50% to 85% by mass, more preferably 55% to 83% by mass, and further preferably 58% to 80% by mass, relative to the total amount (100% by mass) of the styrene resin composition. When the content of the styrene component is within the range of 50% to 85%, a styrene resin composition having excellent balance between moldability and heat resistance can be obtained.

[0256] Regarding the styrene resin composition in 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 further preferably 34% to 51% by mass, relative to the total amount (100% by mass) of the styrene resin composition. When the content of the unsaturated carboxylic acid component is within the range of 17% to 50% by mass, a styrene resin composition having excellent balance among heat resistance, oil resistance, and strength can be obtained. In particular, when the content of the unsaturated carboxylic acid component is 25% by mass or more, resistance to oil exceeding 90° C. can be obtained.

[0257] <(Meth)acrylic acid monomer composition in styrene resin composition>

[0258] The unsaturated carboxylic acid monomer unit in the present embodiment is preferably a (meth) acrylic monomer unit. The (meth) acrylic monomer unit in the styrene resin composition is preferably 2% to 40% by mass, more preferably 3% to 20% by mass, further preferably 4% to 17% by mass, further preferably 8% to 14% by mass, preferably 10% to 13% by mass, further preferably 10.3% to 13% by mass, further preferably 10.3% to 12.5% ​​by mass, and most preferably 10.5% to 12.5% ​​by mass. When the content of the (meth) acrylic monomer unit in the styrene resin composition is 2% by mass or more, the effect of improving heat resistance can be obtained, and when the content is 40% by mass or less, the viscosity can be suppressed from increasing excessively. In particular, when the content is within the range of 10% to 13% by mass, a styrene resin composition having both a high heat resistance improvement effect and suppressing gel generation at a level that can be applied to transparent sheet applications can be obtained.

[0259] <(Meth)acrylate monomer composition in styrene resin composition>

[0260] The unsaturated carboxylic acid ester monomer unit in the present embodiment is preferably a (meth) acrylic acid ester monomer unit, and the content of the (meth) acrylic acid ester monomer unit in the styrene resin composition is preferably 6% to 55% by mass, preferably in the range of 10% to 50% by mass, more preferably in the range of 14% to 45% by mass, further preferably in the range of 16% to 40% by mass, and further preferably in the range of 20% to 37% by mass, relative to the total amount (100% by 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 fully obtained.

[0261] In addition, especially when emphasis is placed on the moldability and low water absorption of the resin, the content of all (meth)acrylate monomer units contained in the styrene resin composition is preferably 0% by mass to 20% by mass, preferably 0% by mass to 15% by mass, more preferably 0% by mass to 10% by mass, more preferably 0% by mass to 7% by mass, and more preferably 0% by mass to 6% by mass, relative to the total amount (100% by mass) of the styrene resin composition.

[0262] The above-mentioned content of all (meth)acrylate monomers indicates the total amount of (meth)acrylate monomer units present in the styrene resin composition, and therefore the contents of the (meth)acrylate monomer units in the resin (A), the resin (B) and the optionally added resin are also converted.

[0263] <2mm plate haze>

[0264] In the present embodiment, the haze (cloudiness) of a 2 mm plate as a test piece formed of the styrene resin composition is preferably 15% or less, more preferably 7%, further preferably 3% or less, and most preferably 1.5% or less. In particular, when the haze is 3% or less, a molded product having very excellent transparency during molding can be obtained.

[0265] In the present embodiment, the method for producing a 2 mm plate is as described in the examples described later, and the styrene-based resin composition is molded into a 2 mm plate by injection molding under the following conditions.

[0266] Molding machine: EC60N manufactured by Toshiba Machine Co., Ltd.

[0267] Barrel temperature: 220℃-240℃-220℃-200℃

[0268] Measuring: 45mm

[0269] Pressure switch: 10mm

[0270] Injection time: 10 seconds

[0271] Cooldown: 15 seconds

[0272] Injection speed: 23mm / sec

[0273] Holding speed: 23mm / s

[0274] Holding time: 10 seconds

[0275] Mold temperature: 45℃

[0276] "Composition of styrene resin composition"

[0277] The styrene 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% ​​by mass to 100% by mass, more preferably 75% by mass to 95% by mass, based on the entire styrene resin composition.

[0278] The styrene 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 is preferably 70% by mass to 100% by mass, and more preferably 80% by mass to 95% by mass, relative to the entire styrene resin composition.

[0279] The styrene resin composition of the present embodiment comprises resin (A), resin (B) and resin (C), and the total content of resin (A), resin (B) and resin (C) is preferably 70% to 100% by mass, more preferably 80% to 90% by mass, relative to the entire styrene resin composition.

[0280] The styrene 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) is preferably 85% by mass to 100% by mass, and more preferably 90% by mass to 95% by mass, relative to the entire styrene resin composition.

[0281] The styrene resin composition of the present embodiment contains a resin (A), a resin (B), a light stabilizer (C), a UV absorber (D), a monohydric alcohol (E) and a release agent (F), and the total content of the resin (A), the resin (B), the light stabilizer (C), the UV absorber (D), the monohydric alcohol (E) and the release agent (F) is preferably 70% by mass to 100% by mass, and more preferably 80% by mass to 90% by mass, relative to the entire styrene resin composition.

[0282] The styrene resin composition of the present embodiment comprises a resin (A), a resin (B), a light stabilizer (C), a UV absorber (D), a monohydric alcohol (E), a release agent (F) and an additive, and the total content of the resin (A), the resin (B), the light stabilizer (C), the UV absorber (D), the monohydric alcohol (E), the release agent (F) and the additive is preferably 85% by mass to 100% by mass, and more preferably 90% by mass to 95% by mass, relative to the entire styrene resin composition.

[0283] "Particularly preferred embodiment of the styrene resin composition"

[0284] A particularly preferred embodiment of the present embodiment is the following styrene-based resin composition, wherein the styrene-based resin composition contains:

[0285] 59% by mass or more and 89% by mass or less of a styrene-unsaturated carboxylic acid resin (A) having a styrene monomer unit (1) and an unsaturated carboxylic acid monomer unit (a1); and

[0286] 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),

[0287] The styrene resin composition contains 0.001% to 2.0% by mass of a light stabilizer (C) and 0.001% to 2.0% by mass of a UV absorber (D) relative to the total amount (100% by mass) of the styrene resin composition.

[0288] The content of all styrene monomer units in the styrene resin composition is 58.8% by mass to 71.6% by mass.

[0289] The (meth)acrylic resin (B) is a copolymer comprising methyl methacrylate monomer units and methyl acrylate monomer units.

[0290] The total content of all methyl methacrylate monomer units and all methyl acrylate monomer units in the styrene-based resin composition is 16% by mass to 40% by mass with respect to the entire styrene-based resin composition.

[0291] Thereby, it is possible to provide a styrene-based resin composition which has excellent compatibility with an acrylic resin and can be used for a molded article having excellent weather resistance, mechanical strength, and oil resistance without reducing heat resistance and transparency.

[0292] [Method for producing styrene resin composition]

[0293] In the present embodiment, regarding the method for manufacturing a styrene resin composition, there is no particular restriction on the method for blending, melting, mixing, and granulating each raw material component, and a method commonly used in the manufacture of a styrene resin composition can be used. For example, the above-mentioned components after blending (mixing) using a drum, a Henschel mixer, etc. are melted and mixed using a Banbury mixer, a single screw extruder, a twin screw extruder, a kneader, etc., and granulated using a rotary cutter, a fan-type cutter, etc., thereby obtaining a resin composition. The resin temperature during melting and mixing is preferably 180°C to 270°C. In order to achieve the target resin temperature, the barrel temperature of the extruder, etc. is preferably set to a temperature 10°C to 20°C lower than the resin temperature. When the resin temperature is less than 180°C, mixing is insufficient, which is not preferred. On the other hand, when the resin temperature exceeds 270°C, thermal decomposition of the resin occurs, which is not preferred.

[0294] [Molding products]

[0295] The method for manufacturing a molded article using the styrene resin composition of the present embodiment is as follows. The styrene resin composition can be manufactured into a molded article using the above-mentioned melt-kneading molding machine; or, the obtained pellets of the styrene resin composition can be used as raw materials to manufacture a molded article using injection molding, injection compression molding, extrusion molding, blow molding, press molding, vacuum molding, and foaming molding. Among them, injection molding is preferred.

[0296] <Injection molded products>

[0297] Another aspect of the present disclosure is a molded article produced by injection molding the above-described styrene-based resin composition, which is excellent in heat resistance, transparency, weather resistance, mechanical strength, and surface hardness and can be suitably used for vehicle applications.

[0298] Specifically, there can be mentioned a lighting cover or a vehicle-mounted injection-molded product made of a styrene-based resin composition.

[0299] Example

[0300] Next, the present invention will be described in more detail by way of examples and comparative examples, but the present invention is not limited to these examples. The analysis and evaluation methods of the resins and molded articles in the examples and comparative examples are as follows.

[0301] [Evaluation of properties of each resin and resin composition]

[0302] (1) Determination of weight average molecular weight

[0303] The weight average molecular weight (Mw) of each resin and resin composition produced in Examples and Comparative Examples was measured using gel permeation chromatography (GPC) under the following conditions.

[0304] Measuring equipment: HLC-8220 manufactured by Tosoh Corporation

[0305] Separation column: Two TSK gel Super HZM-H (inner diameter 4.6 mm) manufactured by TSK Corporation are connected in series.

[0306] Guard column: TSK guard column Super HZ-H manufactured by Tosoh Corporation

[0307] Determination solvent: tetrahydrofuran (THF)

[0308] Sample concentration: 5 mg of a measurement sample was dissolved in 10 mL of a solvent and filtered using a 0.45 μm filter.

[0309] Injection volume: 10 μL

[0310] Measurement temperature: 40℃

[0311] Flow rate: 0.35mL / min

[0312] Detector: Differential refractive index detector

[0313] Eleven types of TSK standard polystyrenes (F-850, F-450, F-128, F-80, F-40, F-20, F-10, F-4, F-2, F-1, and A-5000) manufactured by Tosoh Corporation were used to create the calibration curve. The calibration curve was created using a first-order linear approximation formula.

[0314] (2) Determination of melt mass flow rate (MFR)

[0315] The melt mass flow rate (g / 10 min) of each resin and resin composition produced in Examples and Comparative Examples was measured under the conditions of 200° C. and a load of 49 N in accordance with ISO 1133.

[0316] (3) Determination of Vicat softening temperature

[0317] The Vicat softening temperature of each resin and resin composition manufactured in the examples and comparative examples was measured in accordance with ISO 306. The load was set to 50 N and the heating rate was set to 50° C. / hour. A resin composition having a Vicat softening temperature exceeding 105° C. can obtain an injection molded product that is not easily thermally deformed even at a high temperature of 100° C. or higher.

[0318] (4) Determination of the content of monohydric alcohol (E) having 10 or more carbon atoms and other impurities in styrene resin compositions

[0319] The content of the monohydric alcohol (E) having 10 or more carbon atoms relative to the entire styrene-based resin composition was measured using gas chromatography under the following conditions.

[0320] Sample preparation: 1.0 g of the resin was dissolved in 5 mL of methyl ethyl ketone, and then 5 mL of hexane adjusted to 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 a measurement solution.

[0321] Measurement equipment: 6850 series GC system manufactured by Agilent

[0322] Detector: FID

[0323] Column: DB-WAX

[0324] Length: 60m

[0325] Film thickness: 0.50μm

[0326] Diameter: 0.320mmφ

[0327] Injection volume: 1 μL

[0328] Split ratio: 50:1

[0329] Column temperature: maintain at 100°C for 5 minutes → increase the temperature to 130°C at a rate of 10°C / min → increase the temperature to 180°C at a rate of 10°C / min → maintain at 180°C for 10 minutes → increase the temperature to 220°C at a rate of 20°C / min → maintain at 220°C for 10 minutes

[0330] Inlet temperature: 230°C

[0331] Detector temperature: 300°C

[0332] Carrier gas: Helium

[0333] In order to avoid overlap with other peaks and saturation of peak intensity when detecting the peak of the monohydric alcohol (E) having 10 or more carbon atoms, pretreatment such as sample dilution rate, column used, and detection conditions may be appropriately adjusted.

[0334] (5) Determination of the content of each monomer unit

[0335] The content of each monomer unit contained in the resin compositions prepared in Examples and Comparative Examples was measured by thermal decomposition GC / MS under the following conditions.

[0336] <Measurement Conditions>

[0337] Thermal decomposition unit

[0338] Equipment: PY-3030D manufactured by Frontier Lab

[0339] Heating furnace temperature: 600℃

[0340] Boundary temperature: 300℃

[0341] GC / MS

[0342] Equipment: GCMS-GP2020NX manufactured by Shimadzu Corporation

[0343] Column: Ultra Alloy-5

[0344] (Length 30m, film thickness 0.25μm, diameter 0.250mmφ)

[0345] Column temperature: maintained at 50°C for 5 minutes, increased at a rate of 10°C / min, increased from 100°C at a rate of 7°C / min, and maintained at 300°C for 10 minutes.

[0346] Inlet temperature: 300°C

[0347] Detector temperature: 300°C

[0348] Split ratio: 1 / 300

[0349] Carrier gas: Helium

[0350] Detection method: Mass Analyzer (MSD)

[0351] Sample amount: 50 μg

[0352] Detection mode: Scan mode or SIM mode

[0353] It should be noted that, in order to avoid peak overlap and saturation of peak intensity when detecting each monomer peak, pretreatment such as sample dilution rate, the column used, and detection conditions may be appropriately adjusted.

[0354] (6) Determination of total light transmittance, haze, and YI (yellowness) of 2 mm plate

[0355] Each resin composition prepared in the examples and comparative examples was molded into a 2 mm plate by injection molding, and conditioned in a constant temperature room at 23° C. and a humidity of 50% for more than 48 hours. The haze and YI were then measured using a colorimetric turbidity meter (COH-300A) manufactured by Nippon Denshoku Industries Co., Ltd., and the n3 average value was taken as the value.

[0356] (8) YI (yellowness) measurement of 300 mm long optical path test piece

[0357] Each resin composition prepared in the examples and comparative examples was molded into a 300 mm long optical path test piece by injection molding, and the state was conditioned in a constant temperature room at 23°C and 50% humidity for more than 48 hours. Then, the YI was measured using a Nippon Denshoku long optical path spectroscopic transmission colorimeter (ASA-1), and the n3 average value was used as the value. In particular, when the initial color tone is emphasized, the YI value at the long optical path is sometimes emphasized.

[0358] (9) Evaluation of oil resistance

[0359] Each resin composition prepared in the examples and comparative examples was molded into a 2.5 mm plate by injection molding, and the styrene resin composition plate was immersed in coconut oil (manufactured by Wako Pure Chemical Industries) at 100° C. for 15 minutes. The haze was then measured using a turbidity meter (NDH-2000) manufactured by Nippon Denshoku Industries Co., Ltd. The change in haze before and after the immersion (Δhaze) was calculated according to the following formula, and the hot oil resistance was evaluated according to the following evaluation criteria.

[0360] ΔHaze = Haze after test (%) - Haze before test (%)

[0361] <Evaluation Criteria>

[0362] ◎……ΔHaze is less than 1%

[0363] ○……ΔHaze is 1% or more and 3% or less

[0364] △……ΔHaze is greater than 3% and less than or equal to 5%

[0365] ×……Δhaze is greater than 5%

[0366] (10) Determination of surface hardness

[0367] Each resin composition prepared in the examples and comparative examples was molded into a 2 mm plate by injection molding, and the scratch hardness (pencil method) described in JIS K5600-5-4 was tested at a scratching speed of 0.5 mm / sec to 1.0 mm / sec using a trolley that could be adjusted to a tip load of 750 g and a pencil angle of 45 degrees, to determine the maximum pencil hardness scale at which no scratches were left on the surface.

[0368] (11) Determination of surface impact strength (kg・cm)

[0369] Each resin composition prepared in the examples and comparative examples was dried at 80°C for more than 2 hours using a dryer with a ventilation function, and then molded into a sheet with a thickness of 0.7 mm using a compression molding machine set at a temperature of 250°C. The surface impact strength was measured using a film impact tester (No. 195) manufactured by Toyo Seiki, and the n8 average value was taken as the value.

[0370] (12) Weathering test

[0371] Each resin composition prepared in the examples and comparative examples was molded into a 2 mm plate by injection molding, and a weathering test was performed using a xenon lamp weathering tester Ci4000 manufactured by ATLAS. The conditions were set as rain, black panel temperature of 62°C, and irradiance of 0.4 W / m at 340 nm. 2 The color difference (ΔE) after 1000 hours was measured using a colorimetric turbidity meter (COH-300A) manufactured by Nippon Denshoku Industries Co., Ltd., and the n3 average value was taken as the value.

[0372] [Evaluation of properties of plate-shaped molded products]

[0373] Each resin composition prepared in Examples and Comparative Examples was injection molded using a mold having a cylinder maximum temperature of 250°C and three gates to produce a plate-shaped molded product having a length of 150 mm×width of 300 mm×thickness of 3.5 mm, and subjected to the following evaluation.

[0374] (13) Weather resistance of injection molded products

[0375] The injection molded product was placed outdoors at an altitude of 40 m, and the YI difference (ΔYI) after 2000 hours was measured using a colorimeter (COH-300A) manufactured by Nippon Denshoku Industries Co., Ltd. The n3 average was measured and evaluated according to the following criteria.

[0376] ○: ΔYI is less than 1.0

[0377] △: ΔYI is greater than or equal to 1.0 and less than 2.0

[0378] ×: ΔYI is 2.0 or more

[0379] (14) Molding periodicity

[0380] 300 plate-shaped injection-molded articles were molded, and the number of defective articles mainly due to mold release properties was recorded and evaluated based on the following criteria.

[0381] ◎: The number of defective products is less than 1

[0382] ○: There are 2 or 3 defective products.

[0383] △: The number of defective products is more than 3 and less than 12

[0384] ×: There are 12 or more defective products.

[0385] (15) Formability (fluidity)

[0386] (15-1) Formability (fluidity) -1

[0387] In the evaluation of the moldability (flowability) of the embodiments and comparative examples, an injection molding machine EC60N manufactured by Toshiba Machine Co., Ltd. was used to mold a plate with a thickness of 2 mm under the conditions of a barrel temperature of 210°C, a mold temperature of 45°C, and an injection pressure of 60 MPa. At this time, the evaluation was performed according to the following criteria.

[0388] 0: Can be molded without any problems

[0389] Missing Note: Insufficient filling

[0390] (15-2) Formability (fluidity) -2

[0391] In the evaluation of the moldability (flowability) of the embodiments and comparative examples, a plate with a thickness of 2 mm was molded at a barrel temperature of 220°C and a mold temperature of 45°C using an injection molding machine EC60N manufactured by Toshiba Machine Co., Ltd., and the lowest injection pressure that can be molded without undershot was evaluated. In this evaluation, the lower the injection pressure that can be molded, the more complex the shape of the molded product or the molded product with a thin wall portion can be molded without undershot at a lower barrel temperature. By being able to mold at a low barrel temperature, the following effects are achieved: the cooling time is shortened, the molding cycle is shortened, the volatile components are reduced, and mold contamination is less likely to occur.

[0392] (16) Formability (water absorption)

[0393] In the evaluation of the moldability (flowability) of the embodiments and comparative examples, the pellets were left to stand for 24 hours under the conditions of 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. under the conditions of a barrel 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 (silver streaks) due to moisture in the resin were observed was evaluated according to the following criteria.

[0394] ◎:0~1

[0395] 0: 1 to 4

[0396] △: 5 to 9

[0397] ×: 10 or more

[0398] (17) Mold contamination during injection molding

[0399] For the styrene resin composition, injection molded sheets were prepared at 220°C according to JIS K 7152. At this time, mold contamination was evaluated using the number of injections until deposits were confirmed on the mold after continuous molding as an index. The number of injections until deposits were confirmed on the mold was evaluated according to the following criteria.

[0400] 0: 100 times or more

[0401] △: 50 to 100 times

[0402] ×: Less than 50 times

[0403] (18) Surface appearance of injection molded products

[0404] Ten of the above injection-molded articles were molded, and the presence or absence of foreign matter on both surfaces of the molded articles was visually observed and evaluated based on the following criteria.

[0405] 0: The number of foreign objects is 5 or less

[0406] △: The number of foreign objects is greater than or equal to 5 and less than 10

[0407] ×: The number of foreign objects is 10 or more

[0408] (19) Transparency of injection molded products

[0409] The injection molded product was cut into 50 mm in length by 100 mm in width using an ultrasonic cutter, and the haze of the molded product was measured using a haze meter (NDH-2000) manufactured by Nippon Denshoku Industries Co., Ltd. The n3 average value was measured as the value, and the evaluation was performed based on the following criteria.

[0410] ○: Haze is 3.0% or less

[0411] △: Haze greater than 3.0% and less than or equal to 5.0%

[0412] ×: Haze greater than 5.0%

[0413] (20) Heat resistance of injection molded products

[0414] The injection molded article was placed in a thermostatic bath set at 115° C., taken out after 30 minutes, cooled to room temperature, and then measured for thermal dimensional change in the transverse direction and evaluated according to the following criteria.

[0415] ◎: Dimensional change rate is less than 0.5%

[0416] ○: Dimensional change rate is greater than or equal to 0.5% and less than 1%

[0417] △: Dimensional change rate is greater than or equal to 1% and less than 7%

[0418] ×: Dimensional change rate is 7% or more

[0419] (21) Scratch resistance of injection molded products

[0420] The center of the injection molded product was randomly scratched 20 times with a fingernail, and the scratched portion was cleaned with methanol. The scratches were then visually observed and evaluated based on the following criteria.

[0421] ○: No scratches observed

[0422] △: 1 to 2 scratches were observed

[0423] ×: Three or more scratches were observed

[0424] (22) Strength of injection molded products

[0425] The injection molded product was cut into pieces of 80 mm in length and 80 mm in width using an ultrasonic cutter, and the film impact was measured using a film impact tester (No. 195) manufactured by Toyo Seiki Co., Ltd. Ten samples were measured and evaluated from the following viewpoints.

[0426] ○: Few or more samples were damaged

[0427] △: Three or more but less than five samples were damaged

[0428] ×: More than 6 samples were damaged

[0429] [Preparation of each resin and production example of styrene resin composition]

[0430] Hereinafter, the preparation of each resin and the specific method for producing the styrene-based resin composition will be described.

[0431] <Production Example of Styrene-Unsaturated Carboxylic Acid Resin (A)>

[0432] - Preparation of Resin a-1 -

[0433] A polymerization raw material composition liquid containing 65.5 parts by mass of styrene (containing 20 μg / g of tert-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(tert-butylperoxy)cyclohexane was supplied to a complete mixing reactor with a capacity of 3.6 liters at a rate of 0.8 liters / hour, and then continuously supplied to a devolatilization device connected to a single screw extruder to remove 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°C to 230°C and the pressure was set to 10 Torr to devolatilize volatile components such as unreacted monomers and polymerization solvents. The volatile components after devolatilization were passed through a cooling medium at -5°C, condensed by a condenser, and recovered as an unreacted liquid, and the styrene-based resin was recovered as resin pellets. The physical properties of the resin a-1 obtained by the above-mentioned analysis method are shown in Table 1 below.

[0434] - Preparation of resins a-2, a-3, a-5 to a-13 -

[0435] The feed amount of each monomer and the polymerization conditions were adjusted to prepare resins a-2, a-3 and a-5 to a-13 in the same manner as the above 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.

[0436] - Preparation of Resin a-4 -

[0437] Using only styrene as a monomer, a resin a-4 which is a styrene homopolymer having the composition and physical properties shown in Table 1 was obtained by the same procedure as above.

[0438] [Table 1]

[0439]

[0440] It should be noted that the obtained resins a-1 to a-13 contain about 100 μg / g to about 500 μg / g of residual styrene monomer, about 10 μg / g to about 200 μg / g of ethylbenzene, about 30 μg / g to about 120 μg / g of 2-ethyl-1-hexanol, about 1000 μg / g to about 5000 μg / g of styrene dimers and trimers, and impurities derived from the residue of the above-mentioned polymerization raw material composition. The quantitative determination of these is carried out by the aforementioned gas chromatography using the same method as the quantitative determination of the monohydric alcohol (E) having 10 or more carbon atoms.

[0441] <Production Example of (Meth)Acrylic Resin (B)>

[0442] - Preparation of Resin b-1 -

[0443] Into a 5L container with a stirrer, 2kg of water, 65g of tricalcium phosphate, 39g of calcium carbonate, and 0.39g of sodium lauryl sulfate were added, and they were mixed and stirred to prepare a suspension agent. Then, 26kg of water was added to a 60L reactor, and the temperature was raised to 80°C to prepare for suspension polymerization. After confirming that 80°C was reached and a constant temperature state was formed, 1.56kg of methyl methacrylate, 0.03kg of methyl acrylate, 0.99g of lauroyl peroxide, 4.33g of n-octyl mercaptan and the above-mentioned suspension agent as polymerization raw materials were added. Then, about 80°C was maintained and suspension polymerization was carried out. 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. Then it was cooled to 50°C, and then 20% by mass sulfuric acid was added to dissolve the suspension agent. Next, the polymerization reaction solution was taken out from the 60 L reactor, and the giant coagulates were removed using a sieve with a mesh size of 1.7 mm, and then the water layer and the solid matter were separated using a Buchner funnel to obtain a bead polymer. The bead polymer was washed and dehydrated using about 20 L of distilled water on a Buchner funnel 5 times, and then dried and granulated using a single screw extruder to obtain resin b-1 in the form of a granular resin.

[0444] - Preparation of resins b-2 to b-8 -

[0445] 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 above-mentioned resin b-1. The compositions and physical properties of the obtained resins b-1 to b-8 are shown in Table 2.

[0446] [Table 2]

[0447]

[0448] <<Monohydric alcohol (E) having 10 or more carbon atoms used in the examples>>

[0449] In the examples of the present specification, the following alcohols were used as the monohydric alcohol (E) having 10 or more carbon atoms.

[0450] As the monohydric alcohol (E-1), FINEOXOCOL 180 (compound name: 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-1-octanol) manufactured by Nissan Chemical Co., Ltd. was used.

[0451] KALCOL 8098 (compound name: stearyl alcohol) was used as the monohydric alcohol (E-2).

[0452] As the monool (E-3), EMULGEN 109P (polyoxyethylene (9) lauryl ether monool) manufactured by Kao Corporation was used.

[0453] As the light stabilizer (C), the compounds or products shown in the following Table 3 and chemical structures were used.

[0454] [Table 3]

[0455]

[0456] Light stabilizer c-1:

[0457]

[0458] CAS No.: 52829-07-9

[0459] Light stabilizer c-2:

[0460]

[0461] CAS No.: 705257-84-7

[0462] Light stabilizer c-3:

[0463]

[0464] CAS No.: 64022-61-3

[0465] Light stabilizer c-4:

[0466]

[0467] CAS No.: 41556-26-7

[0468] Light stabilizer c-5:

[0469]

[0470] CAS No.: Mixture of 101357-37-3 and 85631-01-2

[0471] As the ultraviolet absorber (D), the compounds or products shown in the following Table 4 and chemical structures were used.

[0472] [Table 4]

[0473]

[0474] UV absorbers (d.1):

[0475]

[0476] CAS No.: 22440-22-4

[0477] UV absorbers (d.2):

[0478]

[0479] CAS No.: 3147-75-9

[0480] UV absorber (d.3):

[0481]

[0482] CAS No.: 371146-04-2

[0483] UV absorbers (d.4):

[0484]

[0485] CAS No.: 222529-65-9

[0486] UV absorber (d.5):

[0487]

[0488] CAS No.: 1843-05-6

[0489] UV absorbers (d.6):

[0490]

[0491] CAS No.: 147315-50-2

[0492] UV absorbers (d.7):

[0493]

[0494] CAS No.: 178671-58-4

[0495] UV absorbers (d.8):

[0496]

[0497] CAS No.: 7443-25-6

[0498] UV absorbers (d.9):

[0499]

[0500] CAS No.: 6337-43-5

[0501] UV absorber (d.10):

[0502]

[0503] CAS No.: 23949-66-8

[0504] As the following release agent (F), the compounds or products shown in the following Table 5 were used.

[0505] [Table 5]

[0506]

[0507] <Production Example of Crosslinked Body (G)>

[0508] - Preparation of cross-linked body g-1 -

[0509] Preparation of MMA-nBA copolymer cross-linked beads (C) as unmelted compounds

[0510] Into an autoclave equipped with a stirrer were added 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 tricalcium phosphate as suspension stabilizers, and 200 parts by mass of pure water, 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 performed 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.

[0511] - Preparation of cross-linked body g-2 -

[0512] Into 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 tricalcium phosphate as suspension stabilizers, and 200 parts by mass of pure water were added, 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 performed 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.

[0513] - Preparation of cross-linked body g-3 -

[0514] Into 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 tricalcium phosphate as suspension stabilizers, and 200 parts by mass of pure water were added, 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 performed to obtain a crosslinked body (g-3). The crosslinked body (g-3) had an average particle size of 8 μm and a refractive index of 1.494.

[0515] - Preparation of cross-linked body g-4 -

[0516] Into a pressure-resistant container equipped with a stirrer were placed 200 parts by mass of pure water, 0.008 parts by mass of disodium salt of ethylenediaminetetraacetic acid, 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 disodium ethylenediaminetetraacetic acid, and after deoxygenation, 100 parts by mass of butadiene, 0.05 parts by mass of sodium formaldehyde sulfoxylate, and 0.2 parts by mass of terpane hydroperoxide were added, and then 1.4 parts by mass of sodium polyoxyethylene alkyl ether phosphate was added dropwise over 6 hours. Then, the reaction solution was maintained at 50° C. for 124 hours under the condition that the pH in the reaction solution was 6.5 to 7.5, thereby obtaining a diene rubber latex having a conversion rate of 98% by weight and an average particle size of 0.2 μm.

[0517] Next, while the rubber latex obtained above (solid content of about 71 parts) was maintained at 60°C, 55 parts by mass of methyl methacrylate and 5 parts by mass of n-butyl acrylate were added as monomers over 1 hour. In addition, 0.09 parts by mass of tert-butyl hydroperoxide and 0.1 parts by mass of sodium formaldehyde sulfoxylate were added simultaneously with the addition of the above monomers, and then the entire amount of tert-butyl hydroperoxide and sodium formaldehyde sulfoxylate was added over 2 hours while the pH in the reaction solution was maintained at 6.5 to 7.5 and the temperature was maintained at about 60°C. Then, the reaction solution was maintained at about 60°C for 1 hour to prepare a graft copolymer latex having an average particle size of 200 nm, 1 part by mass of Irganox 1076 was added as an antioxidant, and then coagulation treatment was performed using an aqueous calcium chloride solution, and then washing, dehydration and drying were performed to obtain a crosslinked rubber polymer (g-4) in the form of powder.

[0518] In addition, in addition to the cross-linked products shown above, the following products were used as cross-linked products in Examples and Comparative Examples.

[0519] Cross-linked body (g-5): METABLEN W-450A (product name) manufactured by Mitsubishi Chemical Corporation

[0520] Cross-linked product (g-6): Techpolymer MBX-5 (product name) manufactured by Sekisui Chemicals Co., Ltd.

[0521] <<Antioxidant (H) used in Examples>>

[0522] In the examples of the present specification, the following two antioxidants were used as antioxidants.

[0523] ・Phenolic antioxidant h-1: Irganox 1076 manufactured by BASF Japan

[0524] Compound name: Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate

[0525] ・Phenolic antioxidant h-2: Sumilizer GA-80 manufactured by Sumitomo Chemical Co., Ltd.

[0526] 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)propionate]

[0527] ・Phenolic antioxidant h-3: Sumilizer GS manufactured by Sumitomo Chemical Co., Ltd.

[0528] Compound name: 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate

[0529] ・Phosphorus-containing antioxidant h-4: Irgafos 168 manufactured by BASF Japan

[0530] Compound name: Tris(2,4-di-tert-butylphenyl) phosphite

[0531] ・Phosphorus-containing antioxidant h-5: ADK STAB PEP-36 manufactured by ADEKA Corporation

[0532] Compound name: 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane

[0533] ・Phosphorus-containing antioxidant h-6: ADK STAB TPP manufactured by ADEKA Corporation Compound name: Triphenyl phosphite

[0534] ・Phosphorus-containing antioxidant h-7: ADK STAB 3010 manufactured by ADEKA Corporation

[0535] Compound name: Triisodecyl phosphite

[0536] ・Phosphorus-containing antioxidant h-8: ADK STAB PEP-8 manufactured by ADEKA Corporation

[0537] Compound name: 3,9-di(octadecane-1-yl)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane

[0538] ・Hindered phenol skeleton phosphorus-containing antioxidant h-9: Sumilizer GP manufactured by Sumitomo Chemical Co., Ltd.

[0539] Compound name: 6-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-tert-butyldibenzo[d,f][1,3,2]dioxaphosphine

[0540] [Table 6]

[0541]

[0542] <Production Example of Styrene Resin Composition>

[0543] The following is a detailed description of the method for producing the styrene-based resin composition.

[0544] -Example 1-

[0545] 70.0 parts by mass of resin a-1 listed in Table 1 as a styrene-unsaturated carboxylic acid resin (A), 30.0 parts by mass of resin b-1 listed in Table 2 as a (meth) acrylic resin (B), 0.12 parts by mass of bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate listed in Table 3 as a light stabilizer (C), 0.08 parts by mass of 2-(2-hydroxy-5-methylphenyl)benzotriazole listed in Table 4 as a UV absorber (D), 0.11 parts by mass of monohydric alcohol (E-1) FINEOXOCOL 180 (compound name: 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-1-octanol) as a monohydric alcohol (E) having 10 or more carbon atoms, and 0.13 parts by mass of monohydric alcohol (E-2) KALCOL 8098 (compound name: stearyl alcohol) was dry blended, mixed and extruded using a twin-screw extruder TEM26SS manufactured by Shibaura Machine Co., Ltd., and granulated, and then 0.01 parts by mass of ethylene bisstearamide as an external lubricant (F2) was dry blended to obtain a styrene resin composition (1) in the form of a granular resin. The screw speed was set to 150 rpm, the barrel temperature was set to 180°C to 230°C, and the feed rate was set to 10 kg / hour. The resin temperature was 250°C to 260°C. The evaluation results of the obtained styrene resin composition (1) and its molded products are shown in Table 7-1.

[0546] -Examples 2 to 45-

[0547] Styrene resin compositions (2) to (45) and molded articles thereof were obtained in the same manner as in Example 1 except that the compounding ratios were changed as shown in Tables 7-1 to 7-3 below. The evaluation results of each composition and molded article are shown in Tables 7-1 to 7-3.

[0548] [Table 7-1]

[0549]

[0550] [Table 7-2]

[0551]

[0552] [Table 7-3]

[0553]

[0554] -Comparative Examples 1 to 6-

[0555] Resin compositions and molded articles of Comparative Examples 1 to 6 were obtained in the same manner as in Example 1 except that the compounding ratios were changed as shown in Table 8 below. Table 8 shows the evaluation results of each composition and molded article.

[0556] [Table 8]

[0557]

[0558] -Examples 46 to 135-

[0559] Styrene resin compositions (46) to (135) of Examples 46 to 135 and their molded articles were obtained in the same manner as in Example 1 except that the compounding ratios were changed as shown in Tables 9-1 to 10-3 below. The evaluation results of each composition and molded article are shown in Tables 9-1 to 10-3.

[0560] [Table 9-1]

[0561]

[0562] [Table 9-2]

[0563]

[0564] [Table 9-3]

[0565]

[0566] [Table 10-1]

[0567]

[0568] [Table 10-2]

[0569]

[0570] [Table 10-3]

[0571]

[0572] The styrene resin composition disclosed herein is used for a molded product having excellent weather resistance, mechanical strength and oil resistance without reducing heat resistance and transparency. The molded product disclosed herein can be widely used in applications such as vehicle-mounted materials, packaging materials for food containers, heat insulating materials for houses, outer shell materials for lighting equipment, materials for monitors or displays, or light guide plates or light diffusion plates.

Claims

1. A styrene resin composition, wherein: The styrene resin composition comprises: 10% by mass or more and 100% by mass or less of a styrene-unsaturated carboxylic acid resin (A) having a styrene monomer unit (1) and an unsaturated carboxylic acid monomer unit (a1); and 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), and The styrene-based resin composition contains 0% by mass to 2.0% by mass of a light stabilizer (C) and 0.001% by mass to 2.0% by mass of a UV absorber (D) relative to the total amount (100% by mass) of the styrene-based resin composition.

2. The styrene resin composition according to claim 1, wherein The styrene resin composition comprises: 10% by mass or more and less than 100% by mass of a styrene-unsaturated carboxylic acid resin (A) having a styrene monomer unit (1) and an unsaturated carboxylic acid monomer unit (a1); and greater than 0% by mass and less than or equal to 90% by mass of a (meth)acrylic resin (B) having an unsaturated carboxylic acid monomer unit (b1), and The styrene-based resin composition contains 0.001% by mass to 2.0% by mass of a light stabilizer (C) and 0.001% by mass to 2.0% by mass of a UV absorber (D) based on the total amount (100% by mass) of the styrene-based resin composition.

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

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

5. The styrene resin composition according to claim 1 or 2, wherein The ultraviolet absorber (D) is one or more selected from the group consisting of compounds represented by the general formula (d) and the general formula (d'). In the above general formula (d), M di Each independently represents an aromatic group with a valency of one or more, 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, wherein -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 heterocyclic ring), d1 represents an integer of 0 to 4, and d2 represents an integer of 1 to 4. It should be noted that in the above general formula (d), M di With L di The connected wavy lines represent chemical bonds with more than one single bond; 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 1 to 15 carbon atoms, or an aralkyl group having 7 to 25 carbon atoms, wherein -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 heterocyclic ring (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 1 to 15 carbon atoms, or an aralkyl group having 7 to 25 carbon atoms, wherein -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 heterocyclic ring (e.g., a benzotriazole ring)), d5 represents an integer of 0 or more and 4 or less. When d5 is 2 or more, R 8 They may be the same as or different from each other.

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

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

8. The styrene resin composition according to claim 1 or 2, wherein The (meth)acrylic resin (B) is a copolymer containing a methacrylate monomer unit and an acrylate monomer unit.

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

10. The styrene resin composition according to claim 9, wherein 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).

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

12. The styrene resin composition according to claim 1 or 2, wherein The surface scratch hardness of the styrene resin composition measured under the conditions of a pencil tip load of 750 g, a pencil angle of 45 degrees, and a scratching speed of 0.5 mm / sec to 1.0 mm / sec according to the scratch hardness (pencil method) described in JIS K 5600-5-4 is H or higher.

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

14. An injection molded article, wherein The injection-molded article is obtained by injection-molding the styrene-based resin composition according to claim 1 or 2 .

15. A lighting cover, wherein: The lighting cover comprises the styrene resin composition according to claim 1 or 2.

16. An injection molded product for vehicle use, wherein: The vehicle-mounted injection-molded article is obtained by injection-molding the styrene-based resin composition according to claim 1 or 2 .

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