Styrene resin composition, extruded sheet, injection molded article, and container

Abstract

To provide a styrenic resin composition having improved transparency and heat and oil resistance without reduction in heat resistance and impact resistance, and an extrusion sheet including the same, and a container formed by secondary molding of the extrusion sheet.SOLUTION: A styrenic resin composition comprises 40-99 mass% of a styrene-methacrylic acid resin (A) having a styrenic monomer unit (a1) and a methacrylic acid monomer unit (a2-1), and 1-60 mass% of a methacrylic resin (B) having a methacrylate monomer unit (b1).SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to a styrenic resin composition, an extrusion sheet formed using the styrenic resin composition, an injection molded article, and a container formed by secondary molding of the extrusion sheet.

Background Art

[0002] Styrene-unsaturated carboxylic acid resins typified by styrene-methacrylic acid copolymer resins are excellent in heat resistance, transparency, rigidity, and appearance, inexpensive, easy to reuse by thermal decomposition into styrene monomers, and also excellent in chemical recycling characteristics. Therefore, they are widely used as packaging materials for food containers such as lunch boxes and prepared foods, foamed boards for heat insulation materials in houses, diffusion plates for liquid crystal TVs containing diffusing agents, etc. In particular, due to the recent spread of high-power microwave ovens used for business purposes in convenience stores, etc., styrene-unsaturated carboxylic acid resins are used as materials for containers that can withstand the temperature during cooking in high-power microwave ovens and for lid materials that seal or cover such containers. However, it is a problem that the strength is lower than that of general-purpose styrenic resins. For example, Patent Document 1 describes a technique for improving toughness while maintaining practical heat resistance by a mixture of a styrene-methacrylic acid copolymer, impact-resistant polystyrene, and a methyl methacrylate-butadiene-styrene copolymer (hereinafter also referred to as MBS resin).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the technology of the above Patent Document 1, the view of improving mechanical strength was insufficient. Also, in a container assumed to be in direct contact with food, in a conventional styrene-unsaturated carboxylic acid resin, the resin is invaded by high-temperature oil derived from food heated in a range, leading to cracking or strength reduction of the container, so resistance to edible oil is required. Therefore, the problem to be solved by the present invention is to provide a styrene resin composition used for a molded article excellent in heat resistance, mechanical strength, and heat-resistant oiliness. Another problem to be solved by the present invention is to provide a molded article, an extrusion sheet containing a styrene resin composition, and a food container formed by secondary molding of the extrusion sheet, all of which are excellent in heat resistance, mechanical strength, and heat-resistant oiliness.

Means for Solving the Problems

[0005] As a result of intensive research in view of the above problems, the present inventor has succeeded in realizing a styrene resin composition excellent in heat resistance, mechanical strength, and heat-resistant oiliness, an extrusion sheet, an injection molded article, and a container formed by secondary molding of the extrusion sheet by containing a predetermined amount of a styrene-(meth)acrylic acid resin (A) and a (meth)acrylic resin (B) respectively, and has completed the present invention. That is, the present disclosure is as follows.

[0006] [1] The present disclosure is a styrene resin composition containing 40 to 99% by mass of a styrene-(meth)acrylic acid resin (A) having a styrene monomer unit (a1) and a (meth)acrylic acid monomer unit (a2-1), and 1 to 60% by mass of a (meth)acrylic resin (B) having a (meth)acrylic acid ester monomer unit (b1).

[0007] [2] In the present embodiment, it is preferable that the high molecular weight component of 1 million or more is 1.0% by mass or less based on the total amount of the styrene resin composition.

[0008] [3] In this embodiment, it is preferable that the styrene-(meth)acrylic acid resin (A) contains the styrene monomer unit (a1), the (meth)acrylic acid monomer unit (a2-1), and the (meth)acrylic acid ester monomer unit (a2-2).

[0009] [4] The styrene-(meth)acrylic acid resin (A) has two types, the (meth)acrylic acid monomer unit (a2-1) and the (meth)acrylic acid ester monomer unit (a2-2), as essential components. With respect to the entire styrene-(meth)acrylic acid resin (A), the (meth)acrylic acid monomer unit (a2-1) is contained in an amount of 2 to 30% by mass, and the (meth)acrylic acid ester monomer unit (a2-2) is contained in an amount of 1 to 20% by mass. The styrene resin composition is any one of [1] to [3].

[0010] [5] The content of all the (meth)acrylic acid ester monomer units contained in the styrene resin composition is 15 to 50% by mass with respect to the total amount of the styrene resin composition. The styrene resin composition is any one of [1] to [4].

[0011] [6] The (meth)acrylic resin (B) is a methyl methacrylate-methyl acrylate copolymer, and contains the methyl acrylate monomer unit in an amount of 0.5 to 15% by mass with respect to the total amount of the copolymer. The styrene resin composition is any one of [1] to [5].

[0012] [7] The styrene resin composition according to any one of [1] to [6], further containing one or more selected from the group consisting of a (meth)acrylonitrile-diene-styrene resin (C) containing a styrene monomer unit (c1), a conjugated diene monomer unit (c2), and a (meth)acrylonitrile monomer unit (c3), a core-shell type rubber-like polymer particle (D) containing a butadiene monomer unit (d1) and a (meth)acrylic acid ester monomer unit (d2), an impact-resistant styrene resin (E) containing a styrene monomer unit (e1) and a butadiene monomer unit (e2), a styrene elastomer (F), and an acrylic elastomer (G).

[0013] [8] A styrene resin composition according to any one of [1] to [7], further containing a (meth)acrylonitrile-diene-styrene resin (C) containing a styrene monomer unit (c1), a conjugated diene monomer unit (c2), and a (meth)acrylonitrile monomer unit (c3), and an acrylic elastomer (G).

[0014] [9] A styrene resin composition according to any one of [1] to [8], further containing core-shell type rubber-like polymer particles (D) containing a (meth)acrylate monomer unit (d1) and a conjugated diene monomer unit (d2).

[0015]

[10] A styrene resin composition according to any one of [1] to [9], further containing inorganic particles (H) in an amount of 0.05 to 3.0% by mass based on the total amount of the styrene resin composition.

[0016]

[11] One aspect of this embodiment is an extrusion sheet formed by molding a styrene resin composition according to any one of [1] to

[10] .

[0017]

[12] One aspect of this embodiment is a molded article formed by injection molding a styrene resin composition according to any one of [1] to

[10] .

[0018]

[13] One aspect of this embodiment is a container formed by secondary molding the extrusion sheet described in

[11] .

Advantages of the Invention

[0019] According to the present disclosure, it is to provide a styrene resin composition used for a molded article excellent in heat resistance, mechanical strength, and heat-resistant oiliness. According to the present disclosure, it is possible to provide an expanded extrusion sheet and an expanded container capable of being cooked in a microwave oven, which are excellent in heat resistance, mechanical strength, and heat-resistant oiliness.

Brief Description of the Drawings

[0020]

Figure 1

Mode for Carrying Out the Invention

[0021] Hereinafter, a mode for carrying out the present invention (hereinafter referred to as "this embodiment") will be described in detail. The present invention is not limited to the following embodiments, and can be variously modified and implemented within the scope of the gist. [Styrene-based resin composition] The styrene-based resin composition in this embodiment (hereinafter sometimes simply referred to as the resin composition) contains a styrene-(meth)acrylic acid-based resin (A) having styrene monomer units (a1) and (meth)acrylic acid monomer units (a2-1), and a (meth)acrylic resin (B) having (meth)acrylate monomer units (b1). With respect to the total amount (100% by mass) of the styrene-based resin composition, the content of the styrene-(meth)acrylic acid-based resin (A) is 40 to 99% by mass, and the content of the (meth)acrylic resin (B) is 1 to 60% by mass. Further, the styrene-based resin composition in this embodiment may contain, if necessary, one or more selected from the group consisting of a (meth)acrylonitrile-diene-styrene-based resin (C), core-shell type rubber-like polymer particles (D), impact-resistant styrene-based resin (E), styrene-based elastomer (F), acrylic-based elastomer (G), and inorganic particles (H). Thereby, a styrene-based resin composition excellent in heat resistance, mechanical strength, and heat oil resistance can be provided. The styrene-based resin composition in this embodiment is classified into a high molecular weight component of 1 million or more and a molecular weight component of less than 1 million, and it is preferable that the high molecular weight component of 1 million or more is 1.0% by mass or less based on the total amount of the styrene-based resin composition. The high molecular weight component of 1 million or more may contain a styrene-(meth)acrylic acid-based resin (A) and / or a (meth)acrylic-based resin (B). Further, the high molecular weight component of 1 million or more contained in the styrene-based resin composition of this embodiment includes a styrene-(meth)acrylic acid-based resin (A) and / or a (meth)acrylic-based resin (B), and, if necessary, a (meth)acrylonitrile-diene-styrene-based resin (C), a core-shell type rubber-like polymer particle (D), an impact-resistant styrene-based resin (E), a styrene-based elastomer (F), and an acrylic-based elastomer (G). It may contain one or more resins selected from the group consisting of Therefore, the proportion of the high molecular weight component of 1 million or more in the styrene-based resin composition is small.

[0022] "Styrene-(meth)acrylic acid-based resin (A)" The styrene-(meth)acrylic acid resin (A) in the present embodiment is a copolymer resin (hereinafter also simply referred to as resin (A)) containing a styrene monomer unit (a1) and a (meth)acrylic acid monomer unit (a2-1) as essential components, which contributes to the improvement of the heat resistance of the entire styrene resin composition. Further, the styrene-(meth)acrylic acid resin (A) may further have a (meth)acrylic acid ester monomer (a2-2) and / or other monomer units (a3), if necessary, in addition to the essential components which are the styrene monomer unit (a1) and the (meth)acrylic acid monomer unit (a2-1). The content of the styrene-(meth)acrylic acid resin (A) is 40 to 99% by mass, preferably 45 to 98% by mass, more preferably 50 to 97% by mass, and still more preferably 55 to 95% by mass, based on the total amount (100% by mass) of the styrene resin composition. By setting the content of the styrene-(meth)acrylic acid resin (A) to 40% by mass or more, the effect of imparting heat resistance can be sufficiently obtained, and by setting it to 99% by mass or less, the effect of improving oil resistance necessary for improving heat and oil resistance by the (meth)acrylic resin (B) described below can be sufficiently obtained. The styrene-(meth)acrylic acid resin (A) of the present embodiment is preferably a random copolymer or an alternating copolymer.

[0023] <Styrene monomer (a1)> In the styrene-(meth)acrylic acid resin (A) of the present embodiment, the content of the styrene monomer unit (a1) is 60 to 98% by mass, preferably 70 to 97% by mass, more preferably 80 to 96% by mass, and still more preferably 82 to 95% by mass, based on the total amount of the styrene-(meth)acrylic acid resin (A). If the content of the styrene monomer unit (a1) is less than 60% by mass, it will cause a decrease in fluidity, and if it is more than 98% by mass, it will be difficult to contain the (meth)acrylic acid monomer unit (a2-1) described below in a desired amount. In particular, the effect of improving heat resistance by the (meth)acrylic acid monomer unit (a2-1) cannot be sufficiently obtained. In addition, in the styrene resin composition of the present embodiment, the styrene monomer unit (a1) is preferably contained in an amount of 45 to 85% by mass, preferably 48 to 82% by mass, more preferably 52 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 (a1) in the entire composition is within the above range, the effect of improving oil resistance can be sufficiently obtained.

[0024] In the present embodiment, the styrene monomer (a1) is not particularly limited. For example, styrene, α-methylstyrene, β-methylstyrene, paramethylstyrene, orthomethylstyrene, metamexylstyrene, chlorostyrene, bromostyrene, etc. may be mentioned. From an industrial perspective, styrene and α-methylstyrene are particularly preferred, and styrene is more preferred. As the styrene monomer (a1), these can be used alone or in admixture of two or more. In addition, the "styrene monomer unit (a1)" in this specification means a repeating unit that constitutes a polymer obtained by polymerizing the styrene monomer (a1), and is a repeating unit (or structural unit) in which the carbon-carbon double bond in the styrene monomer (a1) has become a single bond (-C-C-) by the polymerization reaction or crosslinking reaction of the styrene monomer (a1). The other monomer units in this specification also have the same meaning.

[0025] <(meth)acrylic acid monomer (a2-1)> In the styrene-(meth)acrylic acid resin (A) of the present embodiment, unsaturated carboxylic acid monomer units such as (meth)acrylic acid monomer units (a2-1) play a role in improving oil resistance and compatibility with the (meth)acrylic resin (B) described later. With respect to the total amount of the styrene-(meth)acrylic acid resin (A), the content of the (meth)acrylic acid monomer unit (a2-1) is preferably 2 to 40% by mass, more preferably 3 to 35% by mass, still more preferably 5 to 30% by mass, even more preferably 8 to 25% by mass, and most preferably 10 to 20% by mass. In another aspect, the content of the (meth)acrylic acid monomer unit (a2-1) is preferably 3 to 20% by mass, more preferably 4 to 17% by mass, and even more preferably 8 to 14% by mass. When the content of the (meth)acrylic acid monomer unit (a2-1) is less than 2% by mass, the effect of improving heat resistance is insufficient. When the content of the (meth)acrylic acid monomer unit (a2-1) exceeds 40% by mass, it is not preferable because of the deterioration of processability due to an increase in resin viscosity, the generation of bubbles during molding due to an increase in water absorption rate, and the viscosity becoming too high during production. By setting the content of the (meth)acrylic acid monomer unit (a2-1) to 2% by mass or more, the effect of improving heat resistance can be obtained, and by setting the content to 40% by mass or less, it is possible to suppress the excessive increase in viscosity. In particular, by setting the content of the (meth)acrylic acid monomer unit (a2-1) to 8 to 25% by mass, good compatibility with the (meth)acrylic resin (B) can be obtained, and the effect of improving the strength during kneading with the (meth)acrylic resin (B) can be efficiently obtained.

[0026] In the present embodiment, the (meth)acrylic acid monomer unit (a2-1) plays a role in improving oil resistance and heat resistance. Examples of the (meth)acrylic acid monomer (a2-1) include acrylic acid or methacrylic acid. In particular, from an industrial perspective, as the (meth)acrylic acid monomer unit (a2-1), these may be used alone or in combination of two or more. The (meth)acrylic acid monomer unit (a2-1) is particularly preferably methacrylic acid, which has a large effect of improving heat resistance.

[0027] -(meth)acrylic acid ester monomer (a2-2)- In this embodiment, the styrene-(meth)acrylic acid resin (A) may further contain a (meth)acrylic acid ester monomer (a2-2). The (meth)acrylic acid ester monomer (a2-2) plays a role in improving oil resistance and strength. As the (meth)acrylic acid ester monomer (a2-2), the following general formula (1):

Chemical formula

[0028] Examples of the (meth)acrylic acid ester monomer (a2-2) in this embodiment include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, cyclohexyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, and the like. These can be used alone or in combination. As the (meth)acrylic acid ester monomer (a2-2), methyl (meth)acrylate or butyl (meth)acrylate is preferable from the viewpoint of easy industrial availability, and methyl methacrylate is particularly preferable from the viewpoint of suppressing a decrease in heat resistance. In this embodiment, with respect to the total amount of the styrene-(meth)acrylic acid resin (A), the content range of the (meth)acrylate monomer unit (a2-2) is preferably, for example, 2 to 40% by mass, more preferably 3 to 32% by mass, still more preferably 3 to 20% by mass, even more preferably 3 to 17% by mass, still even more preferably 3 to 12% by mass, and even still more preferably 4 to 10% by mass.

[0029] <Preferred form of the styrene-(meth)acrylic acid resin (A)> The styrene-(meth)acrylic acid resin (A) of this embodiment may be a copolymer containing a (meth)acrylic acid monomer unit (a2-1) and a (meth)acrylate monomer unit (a2-2). That is, the styrene-(meth)acrylic acid resin (A) of this embodiment, in addition to a binary copolymer of a styrene monomer unit (a1) and a (meth)acrylic acid monomer unit (a2-1), may be a terpolymer in which a styrene monomer (a1), a (meth)acrylic acid monomer (a2-1), and a (meth)acrylate monomer (a2-2) are copolymerized, or a terpolymer containing a styrene monomer unit (a1) and two types of (meth)acrylic acid monomer units (a2-1). Thereby, the effects of improving the compatibility with the (meth)acrylic resin (B), the surface hardness, or the mechanical strength can be further obtained. In particular, when emphasizing the improvement of heat resistance and surface hardness, the styrene-(meth)acrylic acid resin (A) preferably contains a (meth)acrylic acid monomer unit (a2-1). Also, in particular, when emphasizing the improvement of appearance and mechanical strength, the styrene-(meth)acrylic acid resin (A) preferably contains a (meth)acrylate monomer unit (a2-2). Furthermore, when emphasizing the improvement of compatibility with the (meth)acrylic resin (B) and high transparency for a mixture with the resin (B), the styrene-(meth)acrylic acid resin (A) is preferably a terpolymer in which a styrene monomer unit (a1), a (meth)acrylic acid monomer unit (a2-1), and a (meth)acrylate monomer unit (a2-2) are copolymerized. In addition, when unsaturated carboxylic acid ester monomer units such as (meth)acrylic acid ester monomer units (a2-2) are arranged adjacent to unsaturated carboxylic acid monomer units such as (meth)acrylic acid monomer units (a2-1) in the polymer chain, effects such as suppressing the crosslinking reaction between unsaturated carboxylic acids can be obtained. When the styrene-(meth)acrylic acid resin (A) in the present embodiment has a styrene monomer unit (a1), a (meth)acrylic acid monomer unit (a2-1), and a (meth)acrylic acid ester monomer unit (a2-2), the content of the (meth)acrylic acid monomer unit (a2-1) is preferably 2 to 30% by mass, and the content of the (meth)acrylic acid ester monomer unit (a2-2) is preferably 0 to 20% by mass, more preferably, the content of the (meth)acrylic acid monomer unit (a2-1) is 2 to 30% by mass, and the content of the (meth)acrylic acid ester monomer unit (a2-2) is 1 to 20% by mass, still more preferably, the content of the (meth)acrylic acid monomer unit (a2-1) is 2 to 25% by mass, and the content of the (meth)acrylic acid ester monomer unit (a2-2) is 1.5 to 15% by mass, even more preferably, the content of the (meth)acrylic acid monomer unit (a2-1) is 2 to 20% by mass, and the content of the (meth)acrylic acid ester monomer unit (a2-2) is 2 to 13% by mass. By suppressing the content of the (meth)acrylic acid ester monomer unit (a2-2) to 20% by mass or less, a composition excellent in fluidity during molding can be obtained.

[0030] <Other monomer (a3)> The styrene-(meth)acrylic acid resin (A) in the present embodiment may further have other monomer units (a3) other than the above-described styrene monomer unit (a1), (meth)acrylic acid monomer unit (a2-1), and / or (meth)acrylic acid ester monomer unit (a2-2). That is, in the present embodiment, the other monomer unit (a3) may copolymerize with monomers other than the above two monomers without particularly limited as long as it is copolymerizable with the styrene monomer unit (a1), (meth)acrylic acid monomer unit (a2-1) and / or (meth)acrylic acid ester monomer unit (a2-2) without impairing the effects of the invention. For example, examples of the other monomer (a3) other than the three monomers shown above include maleic anhydride, maleic acid, fumaric acid, itaconic acid, (meth)acrylonitrile, dimethyl maleate, dimethyl fumarate, diethyl fumarate, ethyl fumarate, maleimide, and nucleus-substituted maleimide. In the present embodiment, when the styrene-(meth)acrylic acid resin (A) has the other monomer (a3), the content of the other monomer (a3) is preferably 0 to 12% by mass, more preferably 0 to 5% by mass, and still more preferably 2% by mass or less with respect to the total amount of the styrene-(meth)acrylic acid resin (A).

[0031] <Properties of Styrene-(Meth)Acrylic Acid Resin (A)> In the styrene-(meth)acrylic acid resin (A) in the present embodiment, the contents of the styrene monomer unit (a1), (meth)acrylic acid monomer unit (a2-1), (meth)acrylic acid ester monomer unit (a2-2) and other monomer unit (a3) can be quantified by a calibration curve prepared by a resin with known monomer units using thermal decomposition GC / MS. The melt flow rate of the styrene-(meth)acrylic acid resin (A) at 200°C in the present embodiment can preferably be 0.3 to 3.0, more preferably 0.4 to 2.5, and still more preferably 0.4 to 2.0. When the melt flow rate is 0.3 or more, it is preferable from the viewpoint of fluidity, and when it is 3.0 or less, it is preferable from the viewpoint of the mechanical strength of the resin. In the present disclosure, the melt flow rate is a value measured at 200°C and a load of 49 N in accordance with ISO 1133.

[0032] In this embodiment, the weight average molecular weight (Mw) of the styrene-(meth)acrylic acid resin (A) is preferably 100,000 to 400,000, more preferably 120,000 to 320,000. When the weight average molecular weight is 100,000 to 350,000, a resin with excellent practicality in the balance between impact strength and fluidity can be obtained. On the other hand, the number average molecular weight (Mn) of the styrene-(meth)acrylic acid resin (A) is preferably 40,000 to 150,000, more preferably 50,000 to 120,000, and even more preferably in the range of 60,000 to 110,000. The weight average molecular weight and the number average molecular weight can be measured by gel permeation chromatography in terms of polystyrene standard conversion.

[0033] In this embodiment, the Vicat softening temperature of the styrene-(meth)acrylic acid resin (A) is preferably 105 to 140 °C, more preferably 107 to 135 °C, still more preferably 108 to 130 °C, and even more preferably 115 °C to 125 °C. By setting the Vicat softening temperature of the styrene-(meth)acrylic acid resin (A) to 105 °C or higher, the heat resistance improvement effect of the composition can be obtained, and by setting it to 140 °C or lower, it becomes easier to knead with the (meth)acrylic resin (B). The measurement method of the Vicat softening temperature in this specification is measured in accordance with ISO 306.

[0034] <Manufacturing method of styrene-(meth)acrylic acid resin (A)> The manufacturing method of the styrene-(meth)acrylic acid resin (A) of this embodiment will be described below. The manufacturing method of the styrene-(meth)acrylic acid resin (A) of this embodiment preferably includes a step of mixing a styrene monomer (a1), a (meth)acrylic acid monomer (a2-1) and / or a (meth)acrylic acid ester monomer (a2-2), 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. As the polymerization method of the styrene-(meth)acrylic acid resin (A), there is no particular limitation, but for example, a radical polymerization method, and among them, a bulk polymerization method or a solution polymerization method can be preferably adopted. Specifically, the polymerization method mainly includes a polymerization step of polymerizing a polymerization raw material (monomer component) and a devolatilization step of removing volatile components such as unreacted monomers and polymerization solvents from the polymerization product.

[0035] In this embodiment, when polymerizing the polymerization raw material to obtain the styrene-(meth)acrylic 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 like 2,2-bis(t-butylperoxy)butane, 1,1-bis(t-butylperoxy)cyclohexane, n-butyl-4,4-bis(t-butylperoxy)valerate, dialkyl peroxides such as di-t-butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, diacyl peroxides such as acetyl peroxide, isobutyryl peroxide, peroxydicarbonates such as diisopropyl peroxydicarbonate, peroxy esters such as t-butyl peroxyacetate, ketone peroxides such as acetylacetone peroxide, and hydroperoxides such as t-butyl hydroperoxide. From the viewpoints of decomposition rate and polymerization rate, among them, 1,1-bis(t-butylperoxy)cyclohexane is preferred.

[0036] In this embodiment, a chain transfer agent can also be used as needed during the polymerization of the styrene-(meth)acrylic acid resin (A). Examples of the chain transfer agent include, for example, α-methylstyrene linear dimer, n-dodecyl mercaptan, t-dodecyl mercaptan, n-octyl mercaptan, and the like.

[0037] As the polymerization method of the styrene-(meth)acrylic acid resin (A), solution polymerization using a polymerization solvent can be adopted. 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-(meth)acrylic acid resin (A) is adjusted by combining polar solvents such as alcohols or ketones as needed may also be used. In this embodiment, the polymerization solvent is preferably used in the range of 3 to 35 parts by mass, more preferably 5 to 30 parts by mass, based on 100 parts by mass of all the monomers constituting the styrene-(meth)acrylic acid resin (A). When the amount of the polymerization solvent exceeds 35 parts by mass with respect to 100 parts by mass of the all monomers, the polymerization rate decreases, and the molecular weight of the resulting resin also decreases, so the mechanical strength of the resin tends to decrease. On the other hand, when the polymerization solvent is less than 3 parts by mass, it may be difficult to control heat removal during polymerization. Adding in a proportion of 3 to 35 parts by mass with respect to 100 parts by mass of all the monomers is preferable in terms of easy homogenization of quality and also in terms of controlling the polymerization temperature. Also, when adding a monohydric alcohol having 10 or more carbon atoms, which is an optional component of the styrene resin composition of this embodiment, to the polymerization system, it is preferable to add it in a proportion of 1 to 10% by mass with respect to 100% by mass of the total polymerization solvent.

[0038] The apparatus used in the polymerization step for obtaining the styrene-(meth)acrylic acid resin (A) in this embodiment is not particularly limited, and it may be appropriately selected according to the general polymerization method of styrene resins. For example, in the case of bulk polymerization, a complete mixing type reactor or a polymerization apparatus in which a plurality of reactors are connected can be used. Also, there is no particular limitation on the devolatilization step. When performing bulk polymerization, polymerization is carried out until the unreacted monomer finally becomes preferably 50% by mass or less, more preferably 40% by mass or less, and in order to remove volatile components such as such unreacted monomers, devolatilization treatment is performed by a known method. For example, ordinary devolatilization apparatuses such as a flash drum, a twin-screw devolatilizer, a thin-film evaporator, and an extruder can be used, but a devolatilization apparatus with less residence part is preferable. The temperature of the devolatilization treatment is usually about 190 to 280°C, and more preferably 190 to 260°C from the viewpoint of suppressing decomposition. The pressure of the devolatilization treatment is usually about 0.13 to 4.0 kPa, preferably 0.13 to 3.0 kPa, and more preferably 0.13 to 2.0 kPa. As the devolatilization method, for example, a method of removing volatile components by reducing the pressure under heating and a method of removing through an extruder or the like designed for the purpose of removing volatile components are desirable.

[0039] "(Meth)acrylic resin (B)" The styrenic resin composition in the present embodiment contains 2 to 50% by mass of a (meth)acrylic resin (B) (also simply referred to as resin (B)) with respect to the total amount of the styrenic resin composition. And the (meth)acrylic resin (B) has a (meth)acrylate monomer unit (b1). By containing a predetermined amount of the (meth)acrylic resin (B), it contributes to the improvement of the transparency and mechanical strength of the entire styrenic resin composition. In addition, the (meth)acrylic resin (B) in this specification is a general term for synthetic resins in which the content of the (meth)acrylate monomer unit (b1) exceeds 40% by mass. Also, in the present invention, the number average molecular weight (Mn), weight average molecular weight (Mw), Z average molecular weight (Mz) of the (meth)acrylic resin (B), and the ratio of high molecular weight components of 1 million or more in the styrenic resin composition are values measured using gel permeation chromatography (GPC) as described in the column of the examples described later.

[0040] With respect to the total amount (100% by mass) of the styrenic resin composition, the content of the (meth)acrylic resin (B) is 1 to 60% by mass, more preferably 6 to 46% by mass, still more preferably 10 to 42% by mass, even more preferably 14 to 38% by mass, and most preferably 16 to 35% by mass. By setting the content of the (meth)acrylic resin (B) to 10% by mass or more and 40% by mass or less, it is possible to suppress the decrease in heat resistance improved by the styrene-(meth)acrylic acid resin (A). The unsaturated carboxylic acid monomer unit constituting the (meth)acrylic resin (B) of the present embodiment contains a (meth)acrylate monomer unit (b1), preferably a repeating unit containing a (meth)acrylic acid monomer unit (b2) and a (meth)acrylate monomer unit (b1), or a repeating unit containing two or more (meth)acrylate monomer units (b1), and it is more preferable to contain two or more (meth)acrylate monomer units (b1). In the present embodiment, with respect to the total amount of the (meth)acrylic resin (B), the upper limit of the total content of the (meth)acrylate monomer unit (b1) and the (meth)acrylic acid monomer unit (b2) is preferably 100% by mass or less, 99% by mass or less, 98% by mass or less, 80% by mass or less, 75% by mass or less, and 65% by mass or less in this order. Further, the lower limit of the content is preferably 0% by mass or more, 0.5% by mass or more, 1% by mass or more, 2% by mass or more, 5% by mass or more, and 10% by mass or more in this order. The total content of the (meth)acrylate monomer unit (b1) and the (meth)acrylic acid monomer unit (b2) can be arbitrarily combined with the above upper limit and the above lower limit. Hereinafter, the (meth)acrylate monomer unit (b1) and the (meth)acrylic acid monomer unit (b2) of the present embodiment will be described.

[0041] -(Meth)acrylate monomer (b1)- The (meth)acrylate monomer unit (b1) constituting the (meth)acrylic resin (B) of the present embodiment includes a methacrylate monomer unit and an acrylate monomer unit. Further, examples of the (meth)acrylate 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, etc. From the viewpoints of easy industrial availability and low cost, methyl acrylate, (n-butyl) acrylate, and methyl methacrylate are preferred. The (meth)acrylate monomer (b1) can be used alone or in combination, and it is preferable to combine two (meth)acrylate monomers. As a preferred embodiment of the unsaturated carboxylic acid monomer unit constituting the (meth)acrylic resin (B) of the present embodiment, from the viewpoint of achieving both heat resistance and thermal decomposability, among the monomer units listed above, it is preferable to contain two (meth)acrylate monomer (b1), a combination of copolymerizing a methacrylate species and an acrylate species is more preferable, and a methyl methacrylate-methyl acrylate copolymer is even more preferable. In the present embodiment, with respect to the total amount of the (meth)acrylic resin (B), the upper limit of the content of the (meth)acrylate monomer unit (b1) is preferably in the order of 100% by mass or less, 99% by mass or less, 98% by mass or less, 80% by mass or less, 75% by mass or less, and 65% by mass or less. Further, the lower limit of the content is preferably in the order of 0% by mass or more, 0.5% by mass or more, 1% by mass or more, 2% by mass or more, 5% by mass or more, and 10% by mass or more. The content of the (meth)acrylate monomer unit (b1) can be arbitrarily combined with the above upper limit and the above lower limit. The range of the content of the (meth)acrylate monomer unit (b1) is preferably, for example, 0 to 100% by mass, more preferably 2 to 99% by mass, still more preferably 3 to 98% by mass, even more preferably 4 to 98% by mass, still even more preferably 5 to 98% by mass, and particularly preferably 6 to 98% by mass.

[0042] -(meth)acrylic acid monomer (b2)- In the present embodiment, examples of the (meth)acrylic acid monomer (b2) include acrylic acid or methacrylic acid. In the present embodiment, with respect to the total amount of the (meth)acrylic resin (B), the upper limit of the content of the (meth)acrylic acid monomer unit (b2) is preferably in the order of less than 60% by mass, 58% by mass or less, 45% by mass or less, 35% by mass or less, and 25% by mass or less. Further, the lower limit of the content is preferably in the order of 0% by mass or more, more than 0% by mass, 0.5% by mass or more, 1% by mass or more, 2% by mass or more, 5% by mass or more, and 10% by mass or more. The content of the (meth)acrylic acid monomer unit (b2) can be arbitrarily combined with the above upper limit and the above lower limit.

[0043] <Preferred form of (meth)acrylic resin (B)> As the preferred (meth)acrylic resin (B) of the present embodiment, it is preferably a binary or ternary copolymer, and is a methacrylic acid ester-acrylic acid ester copolymer obtained by copolymerizing a methacrylic acid ester species (methacrylic acid ester monomer unit) and an acrylic acid ester species (acrylic acid ester monomer unit). Moreover, a copolymer containing 0.5 to 20% by mass of acrylic acid ester species with respect to the total amount of the methacrylic acid ester-acrylic acid ester copolymer is preferable, a copolymer containing 1.0 to 15% by mass of acrylic acid ester species is more preferable, and a copolymer containing 1.5 to 14% by mass of acrylic acid ester species is still more preferable. Further, the (meth)acrylic resin (B) of the present embodiment is a methyl methacrylate-methyl acrylate copolymer, and a copolymer containing 0.5 to 14% by mass of methyl acrylate with respect to the total amount of the copolymer is still more preferable. Thereby, the decrease in heat resistance improved by the styrene-(meth)acrylic resin (A) can be more effectively suppressed.

[0044] In the (meth)acrylic resin (B) of the present embodiment, the content of the (meth)acrylic acid ester monomer unit (b1) in the (meth)acrylic resin (B) is preferably 40.0 to 100% by mass with respect to the total amount of the (meth)acrylic resin (B), more preferably 50.0 to 99.5% by mass, still more preferably 60.0 to 98.5% by mass, and even more preferably 70 to 98.0% by mass. By setting the content of the (meth)acrylic acid ester monomer (b1) in the range of 40.0 to 100% by mass, it becomes possible to withstand kneading extrusion and molding processing with other resins at 300°C or lower. Therefore, a significant decrease in heat resistance when the styrene-(meth)acrylic resin (A) and the (meth)acrylic resin (B) are mixed can be suppressed. As the type of the (meth)acrylic acid ester monomer (b1), methyl acrylate or methyl methacrylate is preferable because of its heat resistance and easy availability and low cost industrially.

[0045] <Other monomer (b3)> The (meth)acrylic resin (B) of this embodiment may further have other monomer units (b3) other than the above-described (meth)acrylic acid monomer units (b2) and (meth)acrylic acid ester monomer units (b1). That is, the other monomer (b3) may copolymerize with monomers other than the monomers shown above without impairing the effects of the invention as long as it is copolymerizable with the (meth)acrylic acid monomer (b2) and / or the (meth)acrylic acid ester monomer (b1). For example, examples of the other monomer (b3) other than the monomers shown above include styrene, maleic anhydride, maleic acid, fumaric acid, itaconic acid, dimethyl maleate, dimethyl fumarate, diethyl fumarate, ethyl fumarate, maleimide, and nucleus-substituted maleimide. In this embodiment, the content of the other monomer unit (b3) is preferably 0 to 60% by mass, more preferably 0 to 50% by mass, and even more preferably 0 to 40% by mass with respect to the total amount of the (meth)acrylic resin (B).

[0046] The weight average molecular weight (Mw) of the (meth)acrylic resin (B) is preferably 50,000 to 1,000,000, more preferably 60,000 to 900,000, even more preferably 70,000 to 300,000, and still more preferably 80,000 to 200,000. By setting the weight average molecular weight (Mw) of the (meth)acrylic resin (B) to 50,000 or more, strength can be imparted when kneaded with the styrene-(meth)acrylic acid resin (A). By setting the weight average molecular weight (Mw) to 1,000,000 or less, the viscosity difference with the styrene-(meth)acrylic acid resin (A) can be suppressed, the (meth)acrylic resin (B) can be well dispersed in the styrene resin composition, and the generation of unmelted matter derived from the (meth)acrylic resin (B) can be suppressed. A molded article such as a foamed extrusion sheet having a good appearance can be obtained using the composition.

[0047] In addition, the styrene resin composition of this embodiment may contain a high molecular weight component of 1,000,000 or more. When containing a high molecular weight component of 1,000,000 or more, the reduction of heat resistance and rigidity is more suppressed, and the heat and oil resistance is further improved. The proportion of the high molecular weight component of 1,000,000 or more contained in the styrene resin composition is preferably 1.0% by mass or less based on the total amount of the styrene resin composition. In addition, as a method for controlling the high molecular weight component of 1,000,000 or more to 1.0% by mass or less, when radically polymerizing the (meth)acrylic acid ester monomer (b1), it can be controlled by the type and blending amount of the (meth)acrylic acid ester monomer (b1), the type and blending amount of the chain transfer agent, the reaction temperature, the residence time, the type and blending amount of the polymerization initiator, the type and blending amount of the polymerization solvent, etc. Also, as described above, it is more preferable to contain 0.0% by mass or more and 1.0% by mass or less of the high molecular weight component of 1,000,000 or more based on the total amount of the styrene resin composition.

[0048] <Manufacturing method of (meth)acrylic resin (B)> The manufacturing method of the (meth)acrylic resin (B) of this embodiment is not particularly limited, but it can be manufactured by processes such as bulk polymerization for polymerizing the (meth)acrylic acid ester monomer (b1) and other monomers as necessary, solution polymerization with a solvent added, or suspension polymerization in which an organic layer is dispersed in water by a suspending agent.

[0049] <(Meth)acrylonitrile-diene-styrene resin (C)> As a preferred embodiment of this embodiment, the styrene resin composition of this embodiment preferably further contains a (meth)acrylonitrile-diene-styrene resin (C) (also simply referred to as resin (C)) containing a (meth)acrylonitrile monomer unit (c3), a conjugated diene monomer unit (c2), and a styrene monomer unit (c1). By appropriately containing the (meth)acrylonitrile-diene-styrene resin (C) in the styrene resin composition, a styrene resin composition capable of forming a molded body excellent in strength can be obtained. The (meth)acrylonitrile-diene-styrene resin (C) of the present embodiment is a copolymer obtained by polymerizing a (meth)acrylonitrile-based monomer unit (c3), a styrene-based monomer (c1), and, if necessary, other monomer components, and a polymer matrix (C-1) containing, if necessary, other resins, in which rubber-like polymer particles (= rubber-like polymer particles (C-2)) mainly composed of conjugated diene-based monomer units (c2) are dispersed, and can be, for example, a so-called ABS resin. In other words, the (meth)acrylonitrile-diene-styrene resin (C) of the present embodiment contains a polymer matrix (C-1) and rubber-like polymer particles (C-2). The polymer matrix (C-1) contains a copolymer obtained by polymerizing a (meth)acrylonitrile-based monomer unit (c3), a styrene-based monomer (c1), and, if necessary, other monomer components, and, if necessary, other resins. The rubber-like polymer particles (C-2) are particles of a rubber-like polymer mainly composed of conjugated diene-based monomer units (c2). Note that "mainly composed of" in this specification means occupying 50% by mass or more with respect to the whole. Therefore, for example, particles of a rubber-like polymer mainly composed of conjugated diene-based monomer units (c2) (for example, butadiene-based monomer units) mean that the conjugated diene-based monomer units (c2) (for example, butadiene-based monomer units) occupy 50% by mass or more with respect to the whole rubber-like polymer particles (C-2).

[0050] Examples of the styrene-based monomer (c1) include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, ethylstyrene, p-t-butylstyrene, and vinylnaphthalene. Among these, styrene is preferable from the viewpoint of versatility. The styrene-based monomer (c1) may be used alone or in combination of two or more.

[0051] Examples of the conjugated diene monomer unit (c2) of the present embodiment include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, etc. From an industrial perspective, 1,3-butadiene is preferred. The conjugated diene monomer unit (c2) may be used alone or in combination of two or more.

[0052] Examples of the (meth)acrylonitrile monomer unit (c3) include acrylonitrile units, methacrylonitrile units, etc. Among these, from an industrial perspective, acrylonitrile units are preferred. The (meth)acrylonitrile monomer unit (c3) may be used alone or in combination of two or more.

[0053] The mass ratio of the (meth)acrylonitrile monomer unit (c3) to the styrene monomer unit (c1) in the polymer matrix (C-1) constituting the (meth)acrylonitrile-diene-styrene resin (C) is preferably (meth)acrylonitrile monomer unit (c3) / styrene monomer unit (c1) = 5 / 95 to 40 / 60, more preferably 10 / 90 to 35 / 65, still more preferably 15 / 85 to 30 / 70, and most preferably 20 / 80 to 25 / 75. In particular, when the mass ratio is in the range of 20 / 80 to 30 / 70, it has excellent compatibility with the (meth)acrylic resin (B), and the effect of improving the mechanical strength when added to the styrene resin composition is enhanced.

[0054] The content of the rubber-like polymer particles (C-2) mainly composed of the conjugated diene monomer unit (c2) constituting the (meth)acrylonitrile-diene-styrene resin (C) is preferably 5 to 40% by mass, more preferably 10 to 35% by mass, still more preferably 15 to 30% by mass, based on the total amount of the (meth)acrylonitrile-diene-styrene resin (C). By setting the content of the rubber-like polymer particles (C-2) in the range of 5 to 40% by mass, the balance between rigidity and impact resistance when added to the styrene resin composition is excellent.

[0055] The average particle diameter of the rubbery polymer particles (C-2) of the (meth)acrylonitrile-diene-styrene resin (C) is preferably from 0.10 to 1.00 μm, more preferably from 0.13 to 0.90 μm, still more preferably from 0.16 to 0.70 μm, and even more preferably from 0.20 to 0.50 μm. In particular, by setting the average particle diameter in the range of 0.20 to 0.50 μm, the styrenic resin composition has an excellent impact resistance improving effect. In the present disclosure, the method for measuring the average particle diameter is a value measured from a cross-sectional observation image by a transmission electron microscope as shown in the column of Examples described later. Further, as a preferred form of the rubbery polymer particles (C-2), it may be a structure in which a solid rubbery particle containing a conjugated diene monomer unit (c2) as a constituent component is used as a core, and the core is coated with a polymer containing a styrene monomer unit (c1) and a (meth)acrylonitrile monomer unit (c3).

[0056] As a method for producing the (meth)acrylonitrile-diene-styrene resin (C), there are a method of polymer compounding a resin as a main component of a polymer matrix (C-1) prepared in advance by radical bulk polymerization or solution polymerization and ABS rubbery polymer particles (C-2) prepared by graft polymerization onto a rubber latex, and a method of simultaneously preparing the rubbery polymer particles (C-2) and the polymer matrix (C-1) as in the impact-resistant styrenic resin (E) described later. However, an optimum method can be selected as needed.

[0057] In the polymer matrix (C-1) of the (meth)acrylonitrile-diene-styrene resin (C), in addition to a copolymer mainly composed of a (meth)acrylonitrile monomer unit (c3) and a styrene monomer (c1), other polymers may be contained in a range of 25% by mass or less based on the total amount of the (meth)acrylonitrile-diene-styrene resin (C). For example, the heat resistance of the (meth)acrylonitrile-diene-styrene resin (C) may be improved by adding a styrene-acrylonitrile-N-phenylmaleimide copolymer or the like.

[0058] In this embodiment, the melt flow rate of the (meth)acrylonitrile-diene-styrene resin (C) at 200°C is preferably 0.2 to 7.0 g / 10 min, more preferably 0.3 to 6.0 g / 10 min, and still more preferably 0.4 to 5.0 g / 10 min. If the melt flow rate is in the range of 0.2 to 7.0 g / 10 min, the miscibility with the styrene-(meth)acrylic acid resin (A) and the (meth)acrylic resin (B) is good, and the mechanical strength is also good. In the present disclosure, the melt flow rate is a value measured at 200°C and a load of 49 N in accordance with ISO 1133.

[0059] <Core-shell type rubber-like polymer particles (D)> As a preferred embodiment of this embodiment, the styrene resin composition of this embodiment further preferably contains core-shell type rubber-like polymer particles (D) (also simply referred to as core-shell particles (D)) in which a copolymer mainly composed of (meth)acrylate monomer units (d2) is grafted onto rubber-like particles containing conjugated diene monomer units (d1). The core-shell type rubber-like polymer particles (D) of this embodiment have a structure in which rubber-like particles containing conjugated diene monomer units (d1) are used as the core and are coated with a copolymer mainly composed of (meth)acrylate monomer units (d2) so as to cover at least a part of the core.

[0060] The content of the core-shell type rubber-like polymer particles (D) is preferably 1 to 45% by mass, more preferably 2 to 40% by mass, still more preferably 3 to 35% by mass, even more preferably 4 to 30% by mass, and most preferably 5 to 25% by mass based on the total amount of the styrene resin composition. By setting it to 1% by mass or more, the mechanical strength and low-temperature impact resistance can be improved, and by setting it to 25% by mass or less, a decrease in heat resistance and rigidity can be prevented. The conjugated diene monomer (d1) that constitutes the core-shell rubbery polymer particles (D) is a diolefin having a pair of conjugated double bonds, and examples thereof include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, and the like. The (meth)acrylic acid ester monomer unit (d2) that constitutes the core-shell rubbery polymer particles (D) includes a methacrylic acid ester monomer unit and an acrylic acid ester monomer unit. Examples of the (meth)acrylic acid ester monomer unit include methyl acrylate, ethyl acrylate, (n-butyl) acrylate, (2-ethylhexyl) acrylate, (n-octyl) acrylate, benzyl acrylate, methyl methacrylate, butyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, (2-ethylhexyl) methacrylate, (n-octyl) methacrylate, benzyl methacrylate, and the like. From the viewpoints of easy availability and low cost industrially, methyl acrylate, (n-butyl) acrylate, and methyl methacrylate are preferred.

[0061] The content of the conjugated diene monomer unit (d1) in the core-shell rubbery polymer particles (D) is preferably 30 to 90% by mass, more preferably 40 to 85% by mass, still more preferably 50 to 80% by mass, and even more preferably 55 to 75% by mass. The higher the content of the conjugated diene monomer unit (d1), the greater the improvement in mechanical strength with a smaller addition amount, which is preferable. On the other hand, if the content of the conjugated diene monomer unit (d1) is too high, the content of the graft copolymer mainly composed of the (meth)acrylic acid ester monomer unit (d2) decreases, resulting in a decrease in the compatibility with the styrene-(meth)acrylic acid resin (A) and a reduction in the effect of improving mechanical strength.

[0062] In the core-shell rubber-like polymer particles (D), the content of the (meth)acrylate monomer unit (d2) is preferably 10 to 40% by mass, more preferably 12 to 35% by mass, still more preferably 15 to 25% by mass. By setting the content of the methyl (meth)acrylate monomer (d1) in the range of 20 to 70% by mass, compatibility with the matrix polymer portion constituting the styrene-based resin composition of the present embodiment can be ensured, and the effect of improving mechanical strength can be efficiently obtained. The matrix polymer portion essentially contains the resin (A) and the resin (B), and contains one or more selected from the group consisting of the polymer matrix (C-1), the polymer matrix (E-1), the styrene-based elastomer (F), the acrylic-based elastomer (G), the monohydric alcohol having 10 or more carbon atoms, and optional components. In other words, the matrix polymer portion refers to components other than various rubber-like polymer particles and inorganic particles (H) contained in the styrene-based resin composition. Examples of the various rubber-like polymer particles include rubber-like polymer particles (C-2), core-shell rubber-like polymer particles (D), and rubber-like polymer particles (E-2).

[0063] <Particle diameter of the core-shell rubber-like polymer particles (D)> The average particle diameter of the core-shell rubber-like polymer particles (D) is preferably 0.05 to 0.35 μm, more preferably 0.080 to 0.30 μm, still more preferably 0.10 to 0.25 μm, and even more preferably 0.15 to 0.23 μm. In particular, by setting the particle diameter in the range of 0.15 to 23 μm, the effect of imparting strength to the styrene-based resin composition is excellent. In the present disclosure, the measurement method of the average particle diameter is a value measured from a cross-sectional observation image by a transmission electron microscope as shown in the column of Examples described later.

[0064] <Production method of the core-shell rubber-like polymer particles (D)> As a method for producing the core-shell type rubber-like polymer particles (D), an emulsion polymerization method in which conjugated diene rubber latex (for example, butadiene rubber latex) particles are produced and then (meth)acrylic acid ester monomer (d2) is copolymerized is preferable.

[0065] <Impact-resistant styrene resin (E)> As a preferred embodiment of the present embodiment, the styrene resin composition preferably contains an impact-resistant styrene resin (E) (also simply referred to as resin (E)). By appropriately containing the rubber-modified styrene resin (E) in the styrene resin composition, a styrene resin composition capable of producing a molded article excellent in strength can be obtained. The rubber-modified styrene resin (E) of the present embodiment is a so-called high-impact polystyrene resin (HIPS resin) obtained by dispersing particles of a rubber-like polymer (E-2) (= rubber-like polymer particles (E-2)) in a polymer matrix (E-1) of a resin composed of a styrene monomer (e1) and, if necessary, other monomers (e3), and polymerizing the styrene monomer (e1) in the presence of the rubber-like polymer (E-2). In other words, the impact-resistant styrene resin (E) of the present embodiment contains a polymer matrix (E-1) and rubber-like polymer particles (E-2). And the polymer matrix (E-1) contains a polymer obtained by polymerizing a styrene monomer (e1) and, if necessary, other monomers (e3) blended therewith. Further, the rubber-like polymer particles (E-2) are particles of a rubber-like polymer (E-2) mainly composed of conjugated diene monomer units (e2), and the surface of the particles may be grafted with a polymer containing styrene monomer units (e1) if necessary.

[0066] The content of the impact-resistant styrene resin (E) in the styrene resin composition of the present embodiment is preferably 0.5 to 30% by mass, more preferably 2 to 20% by mass, and still more preferably 3 to 15% by mass based on the total amount of the styrene resin composition. By setting the content of the impact-resistant styrene resin (E) in the range of 3 to 15% by mass, a styrene resin composition having more excellent strength can be obtained.

[0067] - Rubber-like polymer particles (E-2)- In the present embodiment, the rubber-like polymer (E-2) constituting the rubber-like polymer particles (E-2) in the impact-resistant styrene-based resin (E) is preferably formed from a conjugated diene monomer (e2), and more preferably a polymer having a conjugated diene monomer unit (e2). Specific examples of the rubber-like polymer (E-2) include polybutadiene, polyisoprene, natural rubber, polychloroprene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, etc. From an industrial perspective, polybutadiene and styrene-butadiene copolymer are preferred. For polybutadiene, high-cis polybutadiene with a high cis content, low-cis polybutadiene with a low cis content, or both can be used. The structure of the styrene-butadiene copolymer may be a random structure, a block structure, or a combination thereof. These rubber-like polymers may be used alone or in combination of two or more. A saturated rubber obtained by hydrogenating a butadiene-based rubber can also be used. In the present specification, the "conjugated diene monomer" is a general term for the aforementioned conjugated diene monomer (c2), conjugated diene monomer (d1), conjugated diene monomer (e2), and conjugated diene monomer (f2). Also, in the present specification, the "rubber-like polymer particles" is a general term for the rubber-like polymer particles (C-2), rubber-like polymer particles (D), and rubber-like polymer particles (E-2). And the conjugated diene monomer is a diolefin having a pair of conjugated double bonds among the monomer units constituting the rubber-like polymer particles. For example, 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, etc. can be mentioned. The rubber-like polymer particles (E-2) in the present embodiment preferably contain a polymer containing styrene-based monomer units (e1) or a polymer containing the styrene-based monomer units (e1) and other monomers (e3) in the dispersed particles of the rubber-like polymer (E-2). As the form of the inclusion, so-called salami-structured dispersed particles in which a plurality of rubber-like polymers (E-2) encapsulate the domain phase of the polymer having styrene-based monomer units (e1) are preferable. Furthermore, a polymer containing styrene-based monomer units (e1) or a polymer containing the styrene-based monomer units (e1) and other monomers (e3) may be grafted on the surface of the rubber-like polymer particles (E-2).

[0068] -Other monomer (e3)- Examples of the other monomer (unit) (e3) which is an optional component of the impact-resistant styrene resin (E) of the present embodiment include (meth)acrylate monomers such as methyl acrylate, ethyl acrylate, propyl acrylate, (n-butyl) acrylate, isopropyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, (n-butyl) methacrylate, and isopropyl methacrylate. From the viewpoint of easy industrial availability, (n-butyl) acrylate and methyl methacrylate are preferable. In the present embodiment, the content of the other monomer (unit) (e3) in the impact-resistant styrene resin (E) is preferably 70% by mass or less, more preferably 60% by mass or less, based on the total amount of the impact-resistant styrene resin (E).

[0069] <Content of conjugated diene-based monomer units (e2)> In the present embodiment, the content of the conjugated diene-based monomer units (e2) in the impact-resistant styrene resin (E) is preferably 0.5 to 15.0% by mass, more preferably 1.0 to 13.0% by mass, and even more preferably 2.0 to 12.0% by mass, based on the total amount of the impact-resistant styrene resin (E). The content of the conjugated diene-based monomer units (e2) in the impact-resistant styrene resin (E) and the styrene resin composition can be measured by the procedure described in the Examples section below or a method equivalent thereto.

[0070] <Average particle diameter of the rubber-like polymer particles (E-2)> In the impact-resistant styrene-based resin (E) in the present embodiment, the rubber-like polymer (E-2) that is a rubber component is present as particles of the rubber-like polymer (E-2) (= rubber-like polymer particles (E-2)) in the styrene-based resin composition. In this case, the average particle diameter of the rubber-like polymer particles (E-2) is preferably 0.3 to 5.0 μm, more preferably 0.5 to 4.0 μm, and still more preferably 0.7 to 3.0 μm. The impact-resistant styrene-based resin (E) is obtained by polymerizing the styrene-based monomer (e1) in a reactor equipped with a stirrer in the presence of the rubber-like polymer particles (E-2). The average particle diameter of the rubber-like polymer particles (E-2) can be adjusted by the rotation speed of the stirrer, the molecular weight of the rubber-like polymer (E-2) used, etc. In the present disclosure, the average particle diameter of the rubber-like polymer particles (E-2) is a value measured from a cross-sectional observation image by a transmission electron microscope as shown in the column of Examples described later. Note that the above rubber-like polymer particles (E-2) are stretched during foaming in the double-foamed sheet described later, and the particle diameter becomes about 150 to 400% larger.

[0071] In the present embodiment, the melt flow rate of the impact-resistant styrene-based resin (E) at 200 °C is preferably 0.5 to 10.0 g / 10 min, more preferably 0.7 to 8.0 g / 10 min, and still more preferably 1.0 to 7.0 g / 10 min. If the above melt flow rate is in the range of 0.5 to 10.0 g / 10 min, the miscibility with the styrene-(meth)acrylic acid-based resin (A) and the (meth)acrylic resin (B) is good, and the mechanical strength is also good. In the present disclosure, the melt flow rate is a value measured at 200 °C and a load of 49 N in accordance with ISO 1133.

[0072] <Method for producing the impact-resistant styrene-based resin (E)> The method for producing the impact-resistant styrene-based resin (E) is not particularly limited, but in the presence of the rubber-like polymer (E-2), bulk polymerization (or solution polymerization) of the styrene-based monomer (e1) and, if necessary, other monomers (e3), and a solvent, bulk-suspension polymerization that shifts to suspension polymerization during the reaction, or emulsion graft polymerization of the styrene-based monomer (e1) in the presence of latex particles that are the rubber-like polymer (E-2) can be used for production. In bulk polymerization, a mixed solution obtained by adding the rubber-like polymer (E-2), the styrene-based monomer (e1), and, if necessary, other monomers (e3), an organic solvent, an organic peroxide, and / or a chain transfer agent is continuously supplied to a polymerization apparatus configured by connecting in series a completely mixed reactor or a tank-type reactor and a plurality of tank-type reactors, whereby production can be achieved.

[0073] <Styrene-based elastomer (F)> As a preferred embodiment of the present embodiment, the styrene-based resin composition preferably further contains a styrene-based elastomer (F) (also simply referred to as elastomer (F)). The styrene-based elastomer (F) used in the styrene-based resin composition of the present invention is a block copolymer having a hard block of a styrene-based monomer (unit) (f1) and a soft block of a conjugated diene-based monomer (unit) (f2). As the elastomer (F), a block copolymer having a hard block of a styrene-based monomer (unit) (f1) and a soft block of a butadiene monomer unit is more preferable. Examples of the styrene-based monomer (f1) include the same monomers as the above-mentioned styrene-based monomer (a1). Examples of the conjugated diene-based monomer (f2) include the same monomers as the above-mentioned conjugated diene-based monomer (c2).

[0074] As the chain structure of the block copolymerization of the styrenic elastomer (F), examples include a styrenic monomer (f1)-butadiene diblock type, a styrenic monomer (f1)-butadiene-styrenic monomer (f1) triblock type, a butadiene-styrenic monomer (f1)-butadiene triblock type, etc. From the viewpoint of improving mechanical strength, a triblock type of styrenic monomer (f1)-butadiene-styrenic monomer (f1) is preferred.

[0075] As the content of the styrenic monomer unit (f1) and the conjugated diene monomer unit (f2) constituting the styrenic elastomer (F), the content of the styrenic monomer unit (f1) is preferably 30 to 70% by mass, more preferably 35 to 65% by mass, and the content of the conjugated diene monomer unit (f2) is the remainder of 100% by mass. If the content of the styrenic monomer unit (f1) is 35 to 65%, the dispersibility in the styrene-(meth)acrylic acid resin (A) becomes moderately good, and those excellent in mechanical strength and appearance can be obtained. As the production method of the styrenic elastomer (F) such as styrene-butadiene elastomer, radical polymerization method, anionic polymerization method, and polymer reaction method can be mentioned, and from an industrial viewpoint, the anionic polymerization method is preferred.

[0076] When the content of the conjugated diene monomer (f2) in the styrenic elastomer (F) exceeds 50% by mass, the content of the styrenic elastomer (F) in the styrenic composition of the present embodiment is preferably 0.5 to 15% by mass, more preferably 1 to 12% by mass, and even more preferably 2 to 7% by mass with respect to the total amount of the styrenic resin composition. On the other hand, when the content of the conjugated diene monomer unit (f2) in the styrenic elastomer (F) is 50% by mass or less, the content of the styrenic elastomer (F) in the styrenic composition is preferably 3 to 30% by mass, more preferably 5 to 20% by mass, and more preferably 7 to 15% by mass with respect to the total amount of the styrenic resin composition. By setting it within the above range, it is possible to suppress a decrease in heat resistance and improve mechanical strength when added to the styrenic resin composition.

[0077] <Acrylic elastomer (G)> As a preferred embodiment of the present embodiment, the styrene resin composition preferably contains an acrylic elastomer (G) (also simply referred to as elastomer (G)). The acrylic elastomer (G) used in the resin composition of the present invention is a block copolymer having a hard block of methyl methacrylate monomer unit (g1) and a soft block of acrylate monomer unit (g2). As the acrylic elastomer (G), a block copolymer having a hard block of methyl methacrylate monomer (unit) and a soft block of acrylate monomer unit (g2) is more preferred. Therefore, although the acrylic elastomer (G) is a block copolymer, the (meth)acrylic resin (B) is different from it in that it is a random polymer or an alternating polymer. Examples of the acrylate monomer (g2) include the same monomers as the acrylate monomer units among the above (meth)acrylate monomer units (b1).

[0078] Examples of the chain structure of the block copolymer of the acrylic elastomer (G) include a methyl methacrylate-acrylate (g2) block type, a methyl methacrylate-acrylate (g2)-methyl methacrylate triblock type, an acrylate (g2)-methyl methacrylate-acrylate (g2) triblock type, etc. From the viewpoint of improving mechanical strength, a triblock type of methyl methacrylate-acrylate (g2)-methyl methacrylate is preferred.

[0079] As the content of methyl methacrylate monomer (g1) and acrylate monomer (g2) constituting the acrylic elastomer (G), the content of methyl methacrylate monomer (g1) is preferably 20 to 65% by mass, more preferably 30 to 55% by mass. On the other hand, the content of acrylate monomer (g2) is the remainder of 100% by mass. When the content of methyl methacrylate monomer (g1) is 20 to 65%, the dispersibility in the styrene-(meth)acrylic resin (A) becomes moderately good, and those excellent in mechanical strength and appearance can be obtained.

[0080] In the styrene-based composition of the present embodiment, the content of the acrylic elastomer (G) is preferably 0.5 to 20% by mass, more preferably 1 to 17% by mass, still more preferably 2 to 15% by mass, based on the total amount of the styrene-based resin composition. By setting it in the range of 0.5 to 20% by mass, it is possible to suppress the decrease in heat resistance and improve the mechanical strength when added to the styrene-based resin composition.

[0081] <Inorganic particles (H)> As a preferred embodiment of the present embodiment, the styrene-based resin composition preferably contains inorganic particles (H). By adding inorganic particles (H) to the styrene-based resin composition, it serves as a foaming nucleating agent during foam molding and contributes to improving the rigidity of the composition and the molded body including the foam sheet.

[0082] Examples of the inorganic particles (H) include kaolin, mica, silica, calcium carbonate, sodium carbonate, barium carbonate, barium sulfate, calcium sulfate, titanium oxide, aluminum oxide, clay, bentonite, talc, diatomaceous earth, etc. Among them, talc, which has abundant application records for food packaging and ensures safety, is preferred.

[0083] When the total amount of the styrene resin composition is 100% by mass, the content of the inorganic particles (H) is preferably 0.1 to 7.0 parts by mass, more preferably 0.2 to 6.0 parts by mass, and even more preferably 0.3 to 4.0 parts by mass. By setting the range to 0.1 to 7.0 parts by mass, a sheet with a suitable expansion ratio for a foamed sheet for food packaging can be obtained.

[0084] There is no particular limitation on the method of adding the inorganic particles (H) to the styrene resin composition. However, it may be directly blended when the styrene resin composition is extrusion-kneaded, or a resin masterbatch containing the inorganic fine particles (H) in a known high concentration may be prepared and added in advance from the viewpoint of easy industrial production.

[0085] "Monohydric alcohol having 10 or more carbon atoms" The monohydric alcohol having 10 or more carbon atoms (hereinafter also simply referred to as alcohol) in the present embodiment is an optional component, which suppresses the gelation of the styrene-(meth)acrylic acid resin (A) during molding and contributes to improving the appearance of the styrene resin composition having a good appearance and the molded body made of the styrene resin composition. The content of the monohydric alcohol having 10 or more carbon atoms is 0.01 to 1.0% by mass, preferably 0.03 to 0.8% by mass, more preferably 0.05 to 0.6% by mass, and even more preferably 0.07 to 0.5% by mass with respect to the total amount (100% by mass) of the styrene resin composition. By setting the content of the monohydric alcohol having 10 or more carbon atoms to 0.01% by mass or more, the gelation of the styrene-(meth)acrylic acid resin (A) during molding can be suppressed, and by setting it to 1.0% by mass or less, the decrease in heat resistance and the generation of odor can be suppressed. By setting the content of the monohydric alcohol having 10 or more carbon atoms to 0.07 to 0.5% by mass, a sufficient gel suppression effect can be obtained without particularly reducing the heat resistance.

[0086] Examples of the monohydric alcohol having 10 or more carbon atoms include alcohols having 10 or more carbon atoms containing one hydroxyl group, which may contain heteroatoms such as oxygen or nitrogen in the carbon chain constituting the alcohol, and may contain bonds other than single bonds such as double bonds, triple bonds, ester bonds, and amide bonds in the carbon chain. The number of carbon atoms is preferably 16 or more, more preferably 17 or more, and even more preferably 18 or more and 50 or less. The monohydric alcohol having 10 or more carbon atoms may be contained in the styrene resin composition or the molded article made of the styrene resin composition. Therefore, by allowing (or adding) a monohydric alcohol having 10 or more carbon atoms to be present in the polymerization solution used when polymerizing the styrene-(meth)acrylic acid resin (A) or the (meth)acrylic resin (B), the monohydric alcohol may remain in the final resin composition product, or it may be contained by adding it when kneading the styrene-(meth)acrylic acid resin (A) and the (meth)acrylic resin (B) and mixing them in an extruder.

[0087] In the present embodiment, the boiling point of the monohydric alcohol 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 the alcohol is less than 260°C, the volatility becomes high, and there is a tendency for a strange odor to occur during molding or the like.

[0088] The monohydric alcohol 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-isoisoeicosanol, 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, polyoxyethylene alkyl ethers, and the like.

[0089] The above polyoxyethylene alkyl ethers are preferably compounds represented by the following general formula (2). [Chemical formula] (In the above general formula (2), R is an alkyl group having 12 to 20 carbon atoms, X represents the average addition number of ethylene oxide, and is an integer of 1 to 15.) Specific product names of preferred alcohols include "Fine Oxocol 180" manufactured by Nissan Chemical Industries, Ltd. and "Emulgen 109P" manufactured by Kao Corporation, etc.

[0090] "Liquid paraffin" As a preferred aspect of the present embodiment, the styrenic resin composition preferably further contains liquid paraffin. The styrenic resin composition containing liquid paraffin exhibits an effect of improving fluidity, the strength of the resin composition and the sheet molding, and reducing cracks during winding. The content of liquid paraffin in the styrenic resin composition of the present embodiment, when 100 parts by mass of the styrene-(meth)acrylic acid resin (A) is used, is preferably 0.05 to 1.5 parts by mass, more preferably 0.10 to 1.0 parts by mass, still more preferably 0.30 to 0.7 parts by mass. If it is 0.05 part by mass or less, the effect of improving fluidity cannot be obtained, and if it is 1.5 parts by mass or more, a decrease in heat resistance is caused.

[0091] The liquid paraffin used in the present embodiment may be referred to as white mineral oil, mineral oil, MO, white mineral oil, etc. in addition to liquid paraffin depending on the degree of purification and business practices. The liquid paraffin used in this embodiment preferably has a naphthene component ratio of 20% or more, more preferably 30% or more, by the n-d-M ring analysis method, because it has excellent compatibility with the styrene-(meth)acrylic acid resin (A). The n-d-M ring analysis method is a composition test method for high-boiling petroleum fractions. By determining the refractive index (n), density (d), and molecular weight (M), the aromatic ring ratio (%Ca), naphthene ring ratio (%Cn), and paraffin chain ratio (%Cp) in the oil can be determined (ASTM D3238). From the perspective of the color of the product, the polycyclic aromatic component in the white mineral oil needs to be 3% or less, preferably 0.5% or less. In liquid paraffin, the aromatic ring is usually 0%.

[0092] It is effective to avoid the problem of volatile components during extrusion molding that the low-boiling components of the liquid paraffin are few. It is preferable that the 5% distillation temperature is 400 °C or higher in terms of the value converted from the reduced-pressure distillation method or gas chromatography method of JIS K2254 to normal pressure. The kinematic viscosity of the liquid paraffin is preferably in a viscosity range where the above-mentioned low-boiling components are few, and effectively lowers the Vicat softening temperature and is easy to handle. The range of 40 to 120 mm 2 2 / s at 40 °C is preferable, and more preferably 60 to 80 mm2 / s.

[0093] The method of adding the liquid paraffin is not particularly limited, and examples include a method of adding the liquid paraffin (E) in the polymerization step, and a method of kneading using a known kneader such as a single-screw extruder, a twin-screw extruder, or a Banbury mixer. In particular, it is preferable to add it during the production of the styrene copolymer (A) because the dispersibility is improved. The quantification and identification of the liquid paraffin in this embodiment can be easily confirmed by a method common to those skilled in the art. For example, a styrenic resin composition or a fragment of a molded article of the composition is dissolved in a solvent that dissolves the matrix resin, such as tetrahydrofuran, to prepare a solution. Then, while stirring this solution with a stirrer, n-hexane is added dropwise little by little to precipitate the matrix resin and the rubbery polymer. Thereafter, the filtrate filtered through a glass filter is evaporated to dryness, then made up to a fixed volume with n-hexane, passed through a membrane filter made of polytetrafluoroethylene, and separated by liquid chromatography to calculate the content of liquid paraffin in the composition or the molded article. Also, for the analysis of liquid paraffin, pyrolysis GC-MS, 1 1H-NMR or 13 13C-NMR and other various analyzers can be used for identification, quantification, and measurement of the molecular weight.

[0094] "Optional additive" In addition to the above components (A) to (H) and monohydric alcohols having 10 or more carbon atoms, the styrenic resin composition of this embodiment may be formulated with various optional additives commonly used in styrenic resins in order to achieve known effects, to form a styrenic resin composition. Examples of the optional additives of this embodiment include stabilizers, higher fatty acid surfactants, antioxidants, ultraviolet absorbers, lubricants, mold release agents, plasticizers, antiblocking agents, antistatic agents, antifogging agents, or mineral oils. There is no particular regulation regarding the method of formulation. For example, there are methods such as adding and polymerizing during polymerization, or mixing the additives in advance with a blender before melt-kneading after polymerization, and then melt-kneading with an extruder or a Banbury mixer.

[0095] As the antioxidant, for example, hindered phenolic antioxidants such as octadecyl-3-(3,5-tert-butyl-4-hydroxyphenyl)propionate and 4,6-bis(octylthiomethyl)-o-cresol (Irganox 1076 as a product), and phosphorus antioxidants such as tris(2,4-di-tert-butylphenyl)phosphite (Irgaflos 176 as a product) can be mentioned. These stabilizers may be used alone or in combination of two or more as appropriate. There is no particular limitation on the addition timing, and it may be either in the polymerization step or the devolatilization step. Also, the stabilizer can be mixed into the product using a mechanical device such as an extruder or a Banbury mixer.

[0096] As a preferred aspect of this embodiment, the styrene resin composition preferably contains a higher fatty acid-based surfactant. By adding the higher fatty acid-based surfactant, not only the blocking prevention effect of the foamed sheet can be obtained, but also by adding an appropriate amount, it contributes to torque reduction between pellets and measurement stability during kneading of the resin composition. Therefore, the content of the higher fatty acid-based surfactant is preferably in the range of 0.002 to 0.1 parts by mass with respect to the total amount of the styrene resin composition. The above effects can be obtained, and by setting it to 0.1 parts by mass or less, it is possible to prevent it from contributing as a gelling agent for the styrene-(meth)acrylic acid resin (A). As a method for adding the higher fatty acid-based surfactant, it may be added during the polymerization of each resin, or may be additionally kneaded during the kneading of the styrene-(meth)acrylic acid resin (A) and the (meth)acrylic resin (B).

[0097] The higher fatty acid-based surfactant is not particularly limited, and examples thereof include stearic acid, calcium stearate, calcium stearate, ethylene bisstearamide, etc. Among them, ethylene bisstearamide is preferred.

[0098] [High molecular weight component of 1 million or more] The styrene resin composition of this embodiment contains the above resin (A) and the above resin (B), and optionally contains one or more selected from the group consisting of (meth)acrylonitrile-diene-styrene resin (C), core-shell type rubber-like polymer particles (D), impact-resistant styrene resin (E), styrene elastomer (F), acrylic elastomer (G), inorganic particles (H), monohydric alcohol having 10 or more carbon atoms, and optional additives. And the styrene resin composition of this embodiment essentially contains resin (A) and resin (B), and has a matrix polymer part which is an optional component and various rubber-like polymer particles. And the matrix polymer part contains one or more selected from the group consisting of polymer matrix (C-1), polymer matrix (E-1), styrene elastomer (F), acrylic elastomer (G), monohydric alcohol having 10 or more carbon atoms, and optional additives. Also, the various rubber-like polymer particles contain one or more selected from the group consisting of rubber-like polymer particles (C-2), core-shell type rubber-like polymer particles (D), and rubber-like polymer particles (E-2). In the matrix polymer part of this embodiment, when the matrix polymer part is divided into a high molecular weight component of 1 million or more and a molecular weight component of less than 1 million, it is preferable that the high molecular weight component of 1 million or more is 1.0% by mass or less based on the total amount of the styrene resin composition. More preferably, it is in the range of 0.9% by mass or less, still more preferably 0.8% by mass or less, even more preferably 0.7% by mass or less, and most preferably 0.6% by mass or less. By setting the high molecular weight component of 1 million or more to 1.0% by mass or less, the amount of unmelted defects is reduced, and a composition excellent in the balance between thin-wall moldability and strength can be obtained. The high molecular weight component of 100 or more is the weight ratio of a molecular weight of 1 million or more before calculating various average molecular weights obtained from GPC, as described in the Examples section below.

[0099] The styrene resin composition of the present embodiment has resin (A) and resin (B), and the total content of resin (A) and resin (B) preferably accounts for 65 to 100% by mass, more preferably 75 to 95% by mass, based on the entire styrene resin composition. The styrene resin composition of the present embodiment has resin (A), resin (B), and optional additive components, and the total content of resin (A), resin (B), and optional additive components preferably accounts for 70 to 100% by mass, more preferably 80 to 95% by mass, based on the entire styrene resin composition. The styrene resin composition of the present embodiment has resin (A), resin (B), and resin (C), and the total content of resin (A), resin (B), and resin (C) preferably accounts for 70 to 100% by mass, more preferably 80 to 90% by mass, based on the entire styrene resin composition. The styrene resin composition of the present embodiment has resin (A), resin (B), resin (C), and optional additive components, and the total content of resin (A), resin (B), resin (C), and optional additive components preferably accounts for 85 to 100% by mass, more preferably 90 to 95% by mass, based on the entire styrene resin composition. The styrene resin composition of the present embodiment has resin (A), resin (B), and rubber-like polymer particles (D), and the total content of resin (A), resin (B), and rubber-like polymer particles (D) preferably accounts for 70 to 100% by mass, more preferably 75 to 95% by mass, still more preferably 80 to 90% by mass, based on the entire styrene resin composition. The styrene resin composition of the present embodiment has resin (A), resin (B), rubber-like polymer particles (D), and optional additive components, and the total content of resin (A), resin (B), rubber-like polymer particles (D), and optional additive components preferably accounts for 80 to 100% by mass, more preferably 85 to 97% by mass, still more preferably 90 to 95% by mass, based on the entire styrene resin composition. When particularly emphasizing the improvement of the Charpy impact strength of an injection molded article, it is preferable that the styrenic resin composition contains resin (A), resin (B), and rubber-like polymer particles (D) in an amount of 70 to 100% by mass or more based on the styrenic resin composition. The styrenic resin composition of this embodiment has resin (A), resin (B), and resin (E), and it is preferable that the total content of resin (A), resin (B), and resin (E) accounts for 70 to 100% by mass, more preferably 80 to 90% by mass, based on the entire styrenic resin composition. The styrenic resin composition of this embodiment has resin (A), resin (B), resin (E), and optional additives, and it is preferable that the total content of resin (A), resin (B), resin (E), and optional additives accounts for 85 to 100% by mass, more preferably 90 to 95% by mass, based on the entire styrenic resin composition. The styrenic resin composition of this embodiment has resin (A), resin (B), and elastomer (F), and it is preferable that the total content of resin (A), resin (B), and elastomer (F) accounts for 70 to 100% by mass, more preferably 80 to 90% by mass, based on the entire styrenic resin composition. The styrenic resin composition of this embodiment has resin (A), resin (B), elastomer (F), and optional additives, and it is preferable that the total content of resin (A), resin (B), elastomer (F), and optional additives accounts for 85 to 100% by mass, more preferably 90 to 95% by mass, based on the entire styrenic resin composition. The styrenic resin composition of this embodiment has resin (A), resin (B), and elastomer (G), and it is preferable that the total content of resin (A), resin (B), and elastomer (G) accounts for 70 to 100% by mass, more preferably 80 to 90% by mass, based on the entire styrenic resin composition. The styrene resin composition of this embodiment has resin (A), resin (B), elastomer (G), and optional additive components, and the total content of resin (A), resin (B), elastomer (G), and optional additive components preferably accounts for 85 to 100% by mass, more preferably 90 to 95% by mass, based on the entire styrene resin composition. The styrene resin composition of this embodiment has resin (A), resin (B), and inorganic particles (H), and the total content of resin (A), resin (B), and inorganic particles (H) preferably accounts for 60 to 100% by mass, more preferably 75 to 98% by mass, based on the entire styrene resin composition. The styrene resin composition of this embodiment has resin (A), resin (B), inorganic particles (H), and optional additive components, and the total content of resin (A), resin (B), inorganic particles (H), and optional additive components preferably accounts for 75 to 100% by mass, more preferably 80 to 98% by mass, based on the entire styrene resin composition. The styrene resin composition of this embodiment has resin (A), resin (B), resin (E), and elastomer (F), and the total content of resin (A), resin (B), resin (E), and elastomer (F) preferably accounts for 70 to 100% by mass, more preferably 85 to 90% by mass, based on the entire styrene resin composition. The styrene resin composition of this embodiment has resin (A), resin (B), resin (E), elastomer (F), and optional additive components, and the total content of resin (A), resin (B), resin (E), elastomer (F), and optional additive components preferably accounts for 85 to 100% by mass, more preferably 90 to 95% by mass, based on the entire styrene resin composition. The styrene resin composition of this embodiment has resin (A), resin (B), resin (C), and elastomer (G), and the total content of resin (A), resin (B), resin (C), and elastomer (G) preferably accounts for 70 to 100% by mass, more preferably 75 to 95% by mass, even more preferably 80 to 90% by mass, based on the entire styrene resin composition. The styrene resin composition of this embodiment has resin (A), resin (B), resin (C), elastomer (G), and optional additives, and the total content of resin (A), resin (B), resin (C), elastomer (G), and optional additives preferably accounts for 80 to 100% by mass, more preferably 85 to 97% by mass, and even more preferably 90 to 95% by mass, based on the entire styrene resin composition. When the styrene resin composition has resin (A), resin (B), resin (C), and elastomer (G), and the total content of resin (A), resin (B), resin (C), and elastomer (G) accounts for 70 to 100% by mass based on the entire styrene resin composition, a styrene resin composition excellent in the balance between low-temperature impact strength and rigidity can be obtained.

[0100] [Physical Properties and Characteristics of Styrene Resin Composition] The physical properties and characteristics of the styrene resin composition in this embodiment are described below. <Vicat Softening Temperature> In this embodiment, the Vicat softening temperature of the styrene resin composition is preferably 105°C or higher, more preferably 109°C or higher, and even more preferably 112°C or higher. By setting the Vicat softening temperature to 105°C or higher, sheets and containers applicable to heat cooking in a general microwave oven of around 500 W can be obtained, and by setting it to 112°C or higher, it can withstand heat cooking in a high-power commercial microwave oven of 1000 W or higher placed in a convenience store, etc. The Vicat softening temperature can be measured under the conditions of a load of 50 N and a temperature increase rate of 50°C / h in accordance with ISO 306.

[0101] <Melt Mass Flow Rate> In this embodiment, the melt flow rate of the styrene resin composition at 200°C is preferably in the range of 0.1 to 2.0 g / 10 min, more preferably 0.2 to 1.5 g / 10 min, and even more preferably 0.4 to 1.0 g / 10 min. By setting the melt flow rate to 0.3 g / 10 min or more, good moldability can be obtained, and by setting it to 2.0 g / 10 min or less, a resin with excellent strength can be obtained.

[0102] <Content of conjugated diene monomer unit> In this embodiment, the content of the conjugated diene monomer unit contained in the styrene resin composition is preferably 0 to 10% by mass, more preferably 0.3 to 5.0% by mass, even more preferably 0.5 to 4.8% by mass, and most preferably 0.6 to 4.0% by mass with respect to the entire styrene resin composition. By setting the content of the conjugated diene monomer unit in the range of 0.6 to 4.0% by mass, a composition excellent in the balance between low-temperature impact strength and rigidity, and a molded article, sheet, and container formed by molding the composition can be obtained. As described above, the conjugated diene monomer unit is a general term for the conjugated diene monomer (c2), the conjugated diene monomer (d1), the conjugated diene monomer (e2), and the conjugated diene monomer (f2).

[0103] <(Meth)acrylic acid monomer or (meth)acrylic acid ester monomer in the styrene resin composition> In this embodiment, the content of all (meth)acrylic acid monomer units contained in the styrene resin composition is preferably 2 to 20% by mass, preferably 3 to 15% by mass, more preferably 4 to 10% by mass, and even more preferably 5 to 8% by mass with respect to the total amount (100% by mass) of the styrene resin composition. When the content of the (meth)acrylic acid monomer in the entire composition is within the above range, the effect of improving heat resistance can be sufficiently obtained. In addition, the content of the above-mentioned total (meth)acrylic acid monomer indicates the total amount of the total (meth)acrylic acid monomer units present in the styrene-based resin composition. Therefore, the respective contents of the (meth)acrylic acid monomer units in resin (A), resin (B) and other components (resin (C), rubber-like polymer particles (D), resin (E), elastomer (G) and optional additive components) are also converted.

[0104] In this embodiment, the content of the total (meth)acrylic acid ester monomer units contained in the styrene-based resin composition is preferably 6 to 55% by mass, preferably 10 to 50% by mass, more preferably 14 to 45% by mass, still more preferably 16 to 40% by mass, based on the total amount (100% by mass) of the styrene-based resin composition. When the content of the (meth)acrylic acid ester monomer in the whole composition is within the above range, the oil resistance necessary for improving the heat resistance and oil resistance and the effect of improving the mechanical strength can be sufficiently obtained. In addition, the content of the above-mentioned total (meth)acrylic acid ester monomer indicates the total amount of the total (meth)acrylic acid ester monomer units present in the styrene-based resin composition. Therefore, the respective contents of the (meth)acrylic acid ester monomer units in resin (A), resin (B) and other components (resin (C), rubber-like polymer particles (D), resin (E), elastomer (G) and optional additive components) are also converted.

[0105] By controlling the contents of the total (meth)acrylic acid monomer units and the total (meth)acrylic acid ester monomer units contained in the styrene-based resin composition within the above ranges, the effect of improving heat resistance by the (meth)acrylic acid monomer units and the effect of improving oil resistance by the (meth)acrylic acid ester monomer units can be efficiently obtained simultaneously. As a result, a styrene-based resin composition excellent in heat resistance and oil resistance and a foamed sheet and a container formed by molding the same can be obtained.

[0106] <Content of styrene-based component in styrene-based resin composition> The styrene-based resin composition in this embodiment contains a styrene-based component. The styrene-based component referred to here is a general term for styrene-based monomers (units) (a1) and styrene-based monomers (units) that may be contained in other components (resin (B), resin (C), rubber-like polymer particles (D), resin (E), elastomer (F), and optional additive components). In the styrene-based resin composition of this embodiment, the content of the styrene-based component (total styrene-based monomers (units)) is preferably 50 to 85% by mass, more preferably 55 to 83% by mass, and still more preferably 58 to 80% by mass, based on the total amount (100% by mass) of the styrene-based resin composition. When it is in the range of 50 to 85, a styrene-based resin composition excellent in the balance of moldability and heat-resistant oiliness can be obtained.

[0107] A preferred embodiment of the styrene-based resin composition in this embodiment is that, based on the total amount (100% by mass) of the styrene-based resin composition, the content of all styrene-based monomer units is 50 to 85% by mass, the content of all (meth)acrylic acid monomer units is 2 to 20% by mass, and the content of all (meth)acrylic acid ester monomer units is 6 to 55% by mass. Another preferred embodiment is that, based on the total amount (100% by mass) of the styrene-based resin composition, the content of all styrene-based monomer units is 50 to 70% by mass, the content of all (meth)acrylic acid monomer units is 3.5 to 10% by mass, the content of all (meth)acrylic acid ester monomer units is 17 to 45% by mass, and the content of all conjugated diene-based monomer units is 0.5 to 10% by mass.

[0108] The average particle diameter of all the rubber-like polymer particles contained in the styrene-based resin composition of this embodiment is preferably 0.08 to 5.0 μm, more preferably 0.10 to 4.0 μm, still more preferably 0.20 to 2.5 μm, and even more preferably 0.25 to 2.0 μm. When the average particle diameter of all the rubber-like polymer particles, so-called apparent rubber-like polymer particles, is within the above range, the strength-imparting effect on the styrene-based resin composition is maximized. The total amount of all rubber-like polymer particles (including the encapsulated resin) in the styrene resin composition of this embodiment is preferably 0.5 to 8.0% by mass, more preferably 0.6 to 6.5% by mass, even more preferably 0.7 to 5.5% by mass, and still more preferably 0.8 to 4.5% by mass with respect to the total amount (100% by mass) of the styrene resin composition. When the content of all rubber-like polymer particles contained in the styrene resin composition is within the above range, the strength-imparting effect on the styrene resin composition is maximized. In addition, the content of all rubber-like polymer particles means that when each rubber-like polymer particle, that is, the ABS rubber-like polymer particle (C-2), the core-shell type rubber-like polymer particle (D), and the rubber-like polymer particle (E-2) each encapsulate a component other than the conjugated diene monomer unit (polymer domain phase), the component other than the conjugated diene monomer unit (polymer domain phase) is also included in the content of all rubber-like polymer particles. The content of the conjugated diene monomer in all rubber-like polymer particles in the styrene resin composition of this embodiment (= rubber amount) is preferably 0 to 10% by mass, more preferably 0.3 to 5.0% by mass, even more preferably 0.5 to 4.8% by mass, and most preferably 0.6 to 4.0% with respect to the total amount (100% by mass) of the styrene resin composition. A styrene resin composition excellent in the balance between strength and rigidity, a molded body, a sheet, and a container formed by molding the composition can be obtained. The above all rubber-like polymer particles include all of the rubber-like polymer particle (C-2), the core-shell type rubber-like polymer particle (D), and the rubber-like polymer particle (E-2).

[0109] [Extruded sheet] Another aspect of the present disclosure provides an extruded sheet formed using the styrene resin composition of the present invention described above. The extruded sheet may be either non-foamed or foamed. As a method for manufacturing the extruded sheet, a commonly known method can be used. As a method for manufacturing a non-foamed extruded sheet, a method using a short-axis or twin-screw extruder equipped with a T-die and a device for taking up the sheet with a single-screw or twin-screw stretcher can be used. As a method for manufacturing a foamed extruded sheet, a method using an extrusion foaming machine equipped with a T-die or a circular die can be used.

[0110] <Foamed extruded sheet> As a method for manufacturing the foamed extruded sheet of the present invention, it can be obtained by the so-called extrusion foaming which is conventionally known. That is, using an extruder, the base resin and various additives such as a foaming nucleating agent (bubble regulator) described later added as necessary are heated, melted, kneaded, a physical foaming agent is injected and further kneaded, and then the foaming molten resin adjusted to an appropriate resin temperature is extruded and foamed under atmospheric pressure through a die.

[0111] In the present embodiment, when forming a foamed extruded sheet, substances commonly used can be used as the foaming agent during extrusion foaming. As the foaming agent, normal butane, isobutane, pentane, chlorofluorocarbon, carbon dioxide, water, diethyl ether, etc. can be used. Butane, isobutane, and diethyl ether are preferred, and two or more of the above foaming agents can also be used in combination. As the addition amount of the foaming agent during foam molding, when the styrene resin composition to be foamed is 100 parts by mass, 0.5 to 8.0 parts by mass is preferred, more preferably 1.0 to 6.0 parts by mass, still more preferably 2.0 to 5.0 parts by mass, and even more preferably 2.5 to 4.5 parts by mass. In particular, when the range is 2.0 to 5.0 parts by mass, the plasticizing effect and foaming properties of the resin are excellent.

[0112] In this embodiment, when forming an extruded foamed sheet, substances commonly used as foaming nucleating agents during extrusion foaming can be used. For example, talc, silica, mica, etc. mentioned as the inorganic particles (H) can be used. When the total amount of the styrene resin composition is 100 parts by mass, the content of the foaming nucleating agent is preferably 0.1 to 7.0 parts by mass, more preferably 0.2 to 6.0 parts by mass, and even more preferably 0.3 to 4.0 parts by mass. By setting the range to 0.1 to 7.0 parts by mass, a sheet with a suitable foaming ratio for a foamed sheet for food packaging can be obtained. As a method of adding the foaming nucleating agent, it may be added directly, or a masterbatch may be used in which resin pellets in which a high-concentration foaming nucleating agent has been dispersed in advance by extrusion kneading are added.

[0113] In this embodiment, the thickness of the extruded foamed sheet is preferably 0.3 mm to 5.0 mm, more preferably in the range of 0.5 to 3.0 mm. By setting the range to 0.5 to 3.0 mm, an extruded foamed sheet excellent in the balance between strength and productivity can be provided.

[0114] In this embodiment, the apparent density of the extruded foamed sheet is preferably 0.05 to 0.30 g / cm 3 and more preferably 0.06 to 0.20 g / cm 3 and even more preferably 0.07 to 0.10 g / cm 3 In particular, by setting the range to 0.07 to 0.10 g / cm 3 an extruded foamed sheet excellent in the balance between strength and productivity can be provided.

[0115] In this embodiment, the basis weight of the extruded foamed sheet is preferably 70 to 300 g / m 2 and more preferably 75 to 250 g / m 2 even more preferably 80 to 200 g / m 2 and even more preferably 90 to 150 g / m 2 In particular, by setting the range to 80 to 200 g / m 2 an extruded foamed sheet excellent in the balance between strength and productivity can be provided.

[0116] In this embodiment, the expansion ratio of the foamed extruded sheet is preferably 5 to 18 times, more preferably 6 to 17 times, still more preferably 7 to 16 times, and even more preferably 8 to 15 times.

[0117] In this embodiment, the closed cell ratio of the foamed extruded sheet determined in accordance with the method of JIS K7138:2006 is preferably 75% or more, more preferably 80% or more, still more preferably 83% or more, and even more preferably 86% or more. In particular, by setting the closed cell ratio to 80% or more, there are few fragile continuous cells, so a foamed sheet excellent in strength can be obtained.

[0118] In this embodiment, the average cell diameter of the foamed extruded sheet is preferably 200 to 500 μm, more preferably in the range of 250 to 450 μm. By setting it in the range of 200 to 500 μm, a foamed extruded sheet excellent in the balance between strength and productivity can be provided.

[0119] The foamed extruded sheet of the present invention may be made into multiple layers by further laminating a film or the like. The type of film to be used may be the same as those used for general polystyrene. For example, a PP (polypropylene) / PS (polystyrene) dry laminate film or the like can be mentioned. The thickness of the film to be laminated is preferably 5 to 200 μm, more preferably 10 to 150 μm, and even more preferably in the range of 20 to 100 μm. By setting it in the range of 20 to 100 μm, it is excellent in the balance of weight reduction, strength, and oil resistance reinforcement. A preferred foamed extruded sheet of this embodiment is a laminate having a foam layer of a styrene resin composition, a polystyrene layer provided on at least one surface of the foam layer, and a polypropylene layer provided on the cotton of the polystyrene layer. With this structure, since the polypropylene layer is provided on the outermost layer that can come into contact with food or the like, a container excellent in oil resistance can be provided. In addition, since the foam layer of the styrene resin composition contains styrene monomer units, a container excellent in compatibility and adhesion with the polystyrene layer can be provided.

[0120] [Secondary molded product] The molded body obtained by thermoforming the foamed sheet is suitably used as a container for microwave-heated foods. Examples of the thermoforming method include vacuum forming and pressure-air forming. Such a thermoforming method is a preferable method because containers can be continuously obtained in a short time. In addition, when thermoforming a laminated sheet obtained by thermocompression-bonding the above-described laminate film, it is preferable to perform the forming so that a polyolefin-based resin film excellent in oil resistance is positioned inside the obtained molded body.

Examples

[0121] Next, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. The analysis and evaluation methods of the resins, extruded sheets, etc. in the Examples and Comparative Examples are as follows.

[0122] [Characteristic evaluation of each resin and resin composition] (1) Measurement of molecular weight and ratio of components having a molecular weight of 1 million or more The average molecular weights (Mn, Mw, Mz) and the ratio of high molecular weight components having a molecular weight of 1 million or more of the resins and resin compositions produced in the Examples and Comparative Examples were measured as standard polystyrene-converted molecular weights by a calibration curve method using standard polystyrene under the following conditions using gel permeation chromatography (GPC). Measuring instrument: HLC-8220 manufactured by Tosoh Corporation Fractionation column: Two TSK gel Super HZM-H (inner diameter 4.6 mm) manufactured by Tosoh Corporation are connected in series Guard column: TSK guard column Super HZ-H manufactured by Tosoh Corporation Measurement solvent: Tetrahydrofuran (THF) Sample concentration: 5 mg of the measurement sample was dissolved in 10 mL of the solvent and filtered through a 0.45 μm filter. Injection volume: 10 μL Measurement temperature: 40°C Flow rate: 0.35 mL / min Detector: Differential refractometer For the preparation of the calibration curve, 11 types of Tosoh's TSK standard polystyrenes (F-850, F-450, F-128, F-80, F-40, F-20, F-10, F-4, F-2, F-1, A-5000) were used. The calibration curve was prepared using the approximate formula of a first-order straight line. When there are THF-insoluble substances in the composition, the THF-insoluble components were removed by a membrane filter of about 0.2 - 0.4 μm and then measured.

[0123] (2) Measurement of the content of monohydric alcohols having 10 or more carbon atoms in the styrene resin composition The content of monohydric alcohols having 10 or more carbon atoms in the entire styrene resin composition was measured under the following conditions using gas chromatography. Sample preparation: After dissolving 1.0 g of the resin in 5 mL of methyl ethyl ketone, 5 mL of hexane adjusted so that p-diethylbenzene as a standard substance became 200 μg / g was added to reprecipitate the polymer component, and the supernatant was collected and used as the measurement solution. Measuring instrument: Agilent 6850 series GC system Detector: FID Column: DB-WAX Length: 60 m Film thickness: 0.50 μm Diameter: 0.320 mm φ Injection volume: 1 μL Split ratio: 50:1 Column temperature: Hold at 100 °C for 5 minutes → Heat up to 130 °C at 10 °C / min → Heat up to 180 °C at 10 °C / min → Hold at 180 °C for 10 minutes → Heat up to 220 °C at 20 °C / min → Hold at 220 °C for 10 minutes Inlet temperature: 230 °C Detector temperature: 300 °C Carrier gas: Helium When detecting the peak of monohydric alcohol (C) having 10 or more carbon atoms, in order to avoid the overlap of other peaks and the saturation of peak intensity, pretreatment such as the dilution ratio of the sample, the column used, and the detection conditions may be appropriately adjusted as needed.

[0124] (3) Measurement of the content of each monomer unit The content of the conjugated diene monomer unit contained in the resin compositions prepared in the examples and comparative examples was measured by pyrolysis GC / MS under the following conditions. Sample preparation: The resin compositions prepared in the examples and comparative examples were weighed into a 50 μg sample cup using an analytical balance and measured under the following conditions. Measurement conditions Pyrolysis unit Equipment: PY-3030D manufactured by Frontier Lab Heating furnace temperature: 600 °C GC Equipment: GCMS-GP2020NX manufactured by Shimadzu Corporation Column: Ultra Alloy-5 (Length 30 m, film thickness 0.25 μm, diameter 0.250 mm φ) Column temperature: Held at 50 °C for 5 minutes, heated at 10 °C / min, heated at 7 °C / min from 100 °C, and held at 300 °C for 10 minutes. Inlet temperature: 300 °C Detector temperature: 300 °C Split ratio: 1 / 300 Carrier gas: Helium Detection method: Mass spectrometer (MSD) In addition, when detecting each monomer peak, in order to avoid peak overlap and peak intensity saturation, the sample amount may be appropriately adjusted, and the column and detection conditions used may be appropriately adjusted as needed.

[0125] (4) Average particle diameter of the rubber-like polymer particles (E-2) in the rubber-like polymer particles (C-2), core-shell type rubber-like polymer particles (D), and impact-resistant styrene resin (E) The average particle diameter (μm) of the rubber-like polymer particles (E-2) in the rubber-like polymer particles (C-2), core-shell type rubber-like polymer particles (D), and impact-resistant styrene resin (E) was determined for 200 rubber-like polymer particles observed by cross-sectional observation using a transmission electron microscope according to the following formula (2): Average particle diameter = Σ(ni × Di 4 ) / Σ(ni × Di 3 ) {In the above formula (2), ni is the number of rubber-like polymer particles having a particle diameter Di, and Di is the average value of the major axis and minor axis of the rubber-like polymer particles.} It was calculated by averaging the particle diameters obtained from the images of 5 visual fields.

[0126] (5) Measurement of melt mass flow rate (MFR) The melt mass flow rate (g / 10 min) of each resin and resin composition produced in the examples and comparative examples was measured under the load conditions of 200 °C and 49 N in accordance with ISO 1133.

[0127] (6) Measurement of Vicat softening temperature The Vicat softening temperature of each resin and resin composition produced in the examples and comparative examples was measured in accordance with ISO 306. The load was 50 N and the heating rate was 50 °C / h. Those with a Vicat softening temperature exceeding 105 °C were excellent in dimensional stability at the temperature assumed when range heating a sheet molding or a container molding, and in particular, those exceeding 115 °C showed almost no dimensional change at the practical temperature.

[0128] (7) Evaluation of heat and oil resistance Each resin composition produced in the examples and comparative examples was molded into a 2.5 mm plate by injection molding, and the styrenic resin composition plate was immersed in coconut oil (manufactured by Wako Pure Chemical Industries, Ltd.) at 105 °C for 15 minutes. The dimensional change rate before and after immersion was calculated by the following formula, and the heat and oil resistance was evaluated according to the following evaluation criteria. (Dimensional change rate after immersion in hot oil) ={(original dimension) - (dimension after immersion)} / (original dimension) × 100 Evaluation criteria ◎ ··· No dimensional change after immersion in hot oil 〇 ··· Dimensional change rate after immersion in hot oil is 2% or less △ ··· Dimensional change rate after immersion in hot oil exceeds 2% and is 10% or less × ··· Dimensional change rate after immersion in hot oil exceeds 10%

[0129] (8) Evaluation of surface impact of solid sheet (kg·cm) After drying each resin composition produced in the examples and comparative examples at 80 °C for 2 hours or more, a solid sheet with a thickness of 0.7 mm was created using a compression molding machine. After cutting it into 8×8 cm, the film impact was measured using a film impact tester (No. 195) manufactured by Toyo Seiki, and the n8 average was used as the value.

[0130] (9) Low-temperature impact strength (-30 °C) of solid sheet Using the styrene resin compositions of the examples and comparative examples, a solid sheet with a thickness of 0.7 mm was prepared using a hot press set at 220 °C, cut into 6 cm×6 cm, cooled in a thermostatic bath set at -30 °C for 2 hours or more, and then the drop hammer impact strength was quickly measured using a DuPont impact tester (No. 451) manufactured by Toyo Seiki. The radius of the impact tip was 6.3 mm and the radius of the impact receiving base was 9.4 mm. The drop hammer impact strength was determined as the value at 50% fracture, calculated as (mass of the falling weight kg)×(height cm).

[0131] (10) Tensile test, flexural test and impact test (10-1) Dumbbell molding of styrene resin composition Each pellet-shaped resin composition produced in the examples and comparative examples was molded into a 4-mm dumbbell of type A using an EC60N manufactured by Toshiba Machine Co., Ltd. under the following conditions. Pellet drying: 80 °C for 2 hours or more Measurement: 63 mm Injection time: 20 seconds Holding pressure time: 10 seconds Cylinder temperature: 220 - 240 - 220 - 200 °C from the nozzle side to the hopper side Screw rotation speed: 100 revolutions per minute Cushion: 5.5 mm Mold temperature: 45 °C Cooling time: 25 seconds (10-2) Dumbbell tensile test (dumbbell tensile fracture point, dumbbell SS curve area) For the 4-mm dumbbell obtained in the previous item (10-1), a dumbbell tensile test was carried out in accordance with JIS K7161 (tensile speed 5 mm / min), and the dumbbell tensile fracture point was measured. Also, the dumbbell SS curve area (N·mm) was calculated from the obtained SS curve. (10-3) Bending Test (Bending Elastic Modulus, Maximum Bending Point) Using a cutting machine, test pieces measuring 80×10×4 mm were prepared from the dumbbell pieces obtained in the previous item (10―1). In accordance with JIS K7171, a bending test was carried out at a bending speed of 2 mm / min, and the bending elastic modulus and the maximum bending point were measured. (10-4) Charpy Impact Test (with Notch) Using a cutting machine, test pieces measuring 80×10×4 mm with a notch were prepared from the dumbbell pieces obtained in the previous item (10―1). In accordance with JIS K7111 / 1eA, the Charpy impact strength was measured.

[0132] [Characteristics Evaluation of Extruded Sheet] (11) Heat Resistance Evaluation of Extruded Sheet Taking the MD direction of the extruded sheets manufactured in the examples and comparative examples as the long side, they were cut into strips measuring 10 cm×1.5 cm, placed in an oven set at 112°C for 30 minutes, and then the deformation of the foamed extruded sheet was measured. The heat resistance was evaluated as follows based on the thermal deformation. Specifically, for the above dimensional change, the change amount of the 10 cm length before and after thermal deformation was measured according to the following formula (I), and the n5 average was used as the value. Formula (I): Dimensional change (%) = (Length in the MD direction of the non-foamed sheet after being placed in the oven for 60 minutes - Length in the MD direction of the non-foamed sheet before being placed in the oven) / Length in the MD direction of the non-foamed sheet before being placed in the oven ◎: No dimensional change 〇: Dimensional change of 0.5% or less △: Dimensional change exceeding 0.5% and 2% or less ×: Dimensional deformation exceeding 2%

[0133] (12) Heat and Oil Resistance Evaluation of Extruded Sheet Taking the MD direction of the extruded sheets manufactured in the examples and comparative examples as the long side, five strips measuring 10 cm×1.5 cm were cut out. After applying about 1 cm of coconut oil (manufactured by Wako Pure Chemical Industries, Ltd.) to the center of the strips, they were placed in an oven set at 110°C in a circular shape for 15 minutes, and then the appearance after being taken out of the oven was evaluated according to the following criteria. ◎: No change in all 5 sheets 〇: Among the 5 sheets, 1 to 2 sheets turn white △: 3 or more whitened out of 5 pieces ×: 3 or more whitened out of 5 pieces, and cracks occur in the sheet

[0134] (13) Surface impact of the extruded sheet After cutting the extruded sheets produced in the examples and comparative examples into 8×8 cm, the film impact was measured using a film impact tester (No. 195) manufactured by Toyo Seiki, and the n8 average was used as the value. The above measurement was carried out in a thermostatic chamber maintained at 23°C.

[0135] (14) Low-temperature impact strength of the extruded sheet (-30°C) The extruded sheets produced in the examples and comparative examples were cut into 6 cm×6 cm, cooled in a thermostatic bath set at -30°C for 2 hours or more, and then the drop weight impact strength was quickly measured using a DuPont impact tester (No. 451) manufactured by Toyo Seiki. The mass of the falling weight was 0.15 kg, the radius of the impact center tip was 6.3 mm, and the radius of the impact center receiving base was 9.4 mm. The drop weight impact strength was determined as the value at 50% fracture, calculated as (mass of the falling weight 0.15 kg)×(height in cm), and evaluated according to the following criteria. ◎: More than 2.0 kg·cm ○: More than 1.0 kg·cm and 2.0 kg·cm or less △: More than 0.1 kg·cm and 1.0 kg·cm or less ×: 0.1 kg·cm or less

[0136] [Characteristic evaluation of the formed container made by secondary molding of the extruded sheet] The extruded sheets produced in the examples and comparative examples were formed into an extruded sheet formed container capable of fitting an inner fitting lid with a diameter of 200 mm and a height of 45 mm using a hot plate molding machine under the conditions of a hot plate temperature of 275°C and a heating time of 5.0 seconds, and used for the evaluations described in (14) and (15) below. (15) Oil resistance during microwave heating of the extruded sheet formed container MCT oil was applied in a circular shape with a diameter of about 1 cm to the central part of the above extruded sheet formed container, moistened by spraying, and 10 samples covered with polyvinylidene chloride film so that moisture would not evaporate were prepared. After heating for 30 seconds with a 1500 W microwave oven, the state of the MCT oil adhering part was visually checked for cracks, and evaluated according to the following evaluation criteria. ◎: All 10 points remain unchanged 〇: The coating part of 1 - 2 points is torn △: The coating part of 3 - 7 points is torn ×: The coating part of 8 points or more is torn (16) Impact strength (kg·cm) of the extruded sheet - formed container A test piece with a size of 80×80 mm in length and width is cut out from the central part of the bottom surface of the above - mentioned extruded sheet - formed container. Using a film impact tester (No.195) manufactured by Toyo Seiki, the film impact is measured in the direction of applying impact to the outer part of the container, and the average value of n8 is used as the value.

[0137] [Characteristic evaluation of the foamed extruded sheet] (17) Basis weight (g / m²) of the foamed extruded sheet 2 ) Excluding 20 mm from both ends of the foamed extruded sheets manufactured in the examples and comparative examples, a sheet section with a size of 0.10×0.10 m is prepared. The mass of each section is measured, and the mass converted per 1.0 m² is calculated as the basis weight (g / m²). 2 is calculated as the basis weight (g / m²). 2 )

[0138] (18) Closed - cell ratio of the foamed extruded sheet The closed - cell ratio of the foamed extruded sheet was measured in accordance with JIS K7138.

[0139] (19) Surface impact of the foamed extruded sheet After cutting the foamed extruded sheets manufactured in the examples and comparative examples into pieces with a size of 8×8 cm, using a film impact tester (No.195) manufactured by Toyo Seiki, the film impact is measured, and the average value of n8 is used as the value.

[0140] (20) Measurement of the heat resistance of the foamed extruded sheet The foamed extruded sheets manufactured in the examples and comparative examples are cut into strips with a size of 10 cm×1.5 cm with the MD direction as the long side. After being placed in an oven set at 110°C for 60 minutes, the deformation of the foamed extruded sheet is measured, and the following evaluation of the heat resistance is made based on the thermal deformation. Specifically, the above dimensional change was measured as the change amount of the length of 10 cm before and after thermal deformation according to the following formula (I), and the n5 average was used as the value. Formula (I): Dimensional change (%) = (Length in the MD direction of the foamed sheet after being placed in the oven for 60 minutes - Length in the MD direction of the foamed extrusion sheet before being placed in the oven) / Length in the MD direction of the foamed extrusion sheet before being placed in the oven ◎: No dimensional change 〇: Dimensional change of 1% or less △: Dimensional change of more than 1% and less than 3% ×: Dimensional deformation of 3% or more

[0141] (21) Measurement of heat and oil resistance of the foamed sheet Palm oil (manufactured by Wako Pure Chemical Industries, Ltd.) was applied to five places in a circular shape with a diameter of about 1 cm on the foamed extrusion sheet formed by molding the styrene resin composition produced in the examples and comparative examples, and after heating in an oven at 80°C for 10 minutes, the state of the palm oil application part was visually evaluated. 〇: No change △: One or two out of the five places in the application part were torn ×: Three or more places in the application part were torn

[0142] (22) Preparation and evaluation of a laminated foamed sheet obtained by laminating a polyolefin-based resin film and a foamed extrusion sheet A CPP / PS laminated film, which is a film (45 μm thick) obtained by laminating CPP 25 μm (Santox KT) and CPS 20 μm (Oishi Sangyo SPH) by dry lamination, and the foamed extrusion sheets produced in the examples and comparative examples were passed between a hot roll at 195°C and a backup roll, and the film was pressure-bonded and laminated to the foamed sheet to obtain a laminated foamed sheet. At this time, the line speed was set to 16 m / min, and the gap between the hot roll and the backup roll was set to 0.5 mm. The heat and oil resistance and surface impact of the laminated foamed sheet were evaluated according to the procedures in the previous items (18) and (20).

[0143] [Characteristic evaluation of a formed container obtained by secondary molding of a foamed extrusion sheet] The foamed extrusion sheets produced in the examples and comparative examples were formed into foamed containers into which a snap-on lid with a diameter of 200 mm and a height of 45 mm could be fitted using a hot plate molding machine under the conditions of a hot plate temperature of 285°C and a heating time of 5.0 seconds, and were subjected to the evaluations described in the following (22) to (24).

[0144] (23) Oil resistance during microwave heating of the foamed container MCT oil was applied in a circular shape with a diameter of about 10 mm to the central part of the above-mentioned foamed container, moistened by spraying, and 10 samples covered with a polyvinylidene chloride film so that moisture would not evaporate were prepared. After heating with a 1500 W microwave for 30 seconds, the state of the part where the MCT oil adhered was visually checked for any breakage, and the evaluation was made according to the following evaluation criteria. ◎: No change in all 10 samples 〇: The coated part was broken in 1 to 2 samples △: The coated part was broken in 3 to 7 samples ×: The coated part was broken in 8 or more samples

[0145] (24) Measurement of the waist strength of the tray container The waist strength of the above-mentioned foamed container was measured by the method shown in FIG. 1. More specifically, with respect to the TD direction of the tray container 1 which is a foamed container, the crosshead 2 was compressed at a compression speed of 5 mm / min, and the waist strength (N) of the tray container 1 was measured.

[0146] (25) Impact strength of the foamed container A test piece measuring 80 mm in length and 80 mm in width was cut out from the central part of the bottom of the above-mentioned foamed container, and the film impact was measured in the direction of applying an impact to the outer part of the container using a film impact tester (No. 195) manufactured by Toyo Seiki, and the n8 average was used as the value, and the evaluation was made from the following viewpoints. ◎: 4.0 kg or more 〇: 2.0 kg·cm or more and 4.0 kg·cm or less ×: Less than 2.0 kg·cm In containers with less than 2.0 kgf, cracks tended to occur in the transport containers.

[0147] (26) Low-temperature impact strength (-30°C) of the foamed sheet Each foamed sheet prepared in the examples and comparative examples was cooled in a thermostatic bath set at -30°C for 2 hours or more, and then evaluated for whether the sheet cracked when a 100 g weight was dropped from a height of 120 cm. Among the 10 samples, the number of samples with fracture was tabulated and evaluated from the following viewpoints. ◎: None of the 10 samples cracked 〇: 1 to 2 of the 10 samples cracked △: 3 to 4 of the 10 samples cracked ×: 5 or more of the 10 samples cracked

[0148] [Preparation of Each Resin and Production Examples of Styrenic Resin Compositions] The preparation of the following resins and the specific production methods of the styrenic resin compositions will be described below. [Production Example of Styrene-(Meth)Acrylic Acid Resin (A)] [Preparation of Resin (A1)] A polymerization raw material composition liquid consisting of 65.5 parts by mass of styrene, 3.3 parts by mass of methyl methacrylate, 5.8 parts by mass of methacrylic acid, 22.9 parts by mass of ethylbenzene, 2.5 parts by mass of 2-ethyl-1-hexanol, and 0.027 parts by mass of 1,1-bis(t-butylperoxy)cyclohexane was supplied to a completely mixed reactor with a capacity of 3.6 liters at a rate of 0.8 liter / hour, and then continuously supplied to a devolatilization device connected to a single-screw extruder for removing volatile components such as unreacted monomers and polymerization solvents. The polymerization temperature of the completely mixed reactor was set at 130°C. The temperature of the single-screw extruder was set at 210 - 230°C and the pressure at 10 torr to devolatilize volatile components such as unreacted monomers and polymerization solvents. The devolatilized volatile components were condensed in a condenser through which a refrigerant at -5°C was passed, recovered as an unreacted liquid, and the styrenic resin was recovered as resin pellets. The physical properties of resin (A1) obtained by the above analysis method are shown in Table 1 below.

[0149] [Preparation of Resin (A2) and Resin (A3)] Using the feed amounts of each monomer described in Table 1, resins (A2) and (A3) were prepared in the same procedure as resin (A1) under the polymerization conditions in the preparation of resin (A1). The compositions and physical properties of the obtained resins (A2) and (A3) are shown in Table 1.

[0150] -Preparation of Resin (A4)- Using only styrene as the monomer, resin (A4) was obtained as a styrene homopolymer with the composition and physical properties shown in Table 1 by the same procedure as above.

[0151]

Table 1

[0152] <Production Example of (Meth)Acrylic Resin (B)> -Preparation of Resin (B1)- 2 kg of water, 65 g of tricalcium phosphate, 39 g of calcium carbonate, and 0.39 g of sodium lauryl sulfate were charged into a 5 L container equipped with a stirrer, and a suspension agent was prepared by mixing and stirring them. Next, 26 kg of water was charged into a 60 L reactor and heated to 80 °C to prepare for suspension polymerization. After confirming that the temperature reached 80 °C and became a constant temperature state, 1.52 kg of methyl methacrylate, 0.22 kg of methyl acrylate, 0.99 g of lauroyl peroxide, 4.93 g of n-octyl mercaptan, and the above suspension agent were charged as polymerization raw materials. Then, suspension polymerization was carried out while maintaining about 80 °C. After observing the exothermic peak, the temperature was raised to 92 °C at a rate of 1 °C / min, and the temperature was maintained at 92 °C for 60 minutes. Subsequently, after cooling to 50 °C, 20 mass% sulfuric acid was added to dissolve the suspension agent. Then, the polymerization reaction solution was taken out from the 60 L reactor, passed through a sieve with a mesh opening of 1.7 mm to remove large aggregates, and then the aqueous layer and the solid matter were separated with a Buchner funnel to obtain a bead-like polymer. The bead-like polymer was washed and dehydrated about 5 times with about 20 L of distilled water on the Buchner funnel, and then dried and pelletized using a single-screw extruder to obtain resin (B1) as a pellet-like resin.

[0153] -Preparation of Resins (B2) to (B6)- Using the feed amounts of each monomer described in Table 2, resins (B2) to (B6) were prepared in the same procedure as resin (B1) under the polymerization conditions in the preparation of resin (B1). The compositions and physical properties of the obtained resins (B2) to (B6) are shown in Table 2.

[0154]

Table 2

[0155] <(Meth)acrylonitrile-diene-styrene resin (C) used in the examples> The general outline of the preparation method of the (meth)acrylonitrile-diene-styrene resin (C) used in this example is as follows: First, a resin (C-2-1) containing butadiene-styrene-acrylonitrile graft copolymer particles (rubbery polymer particles (C-2)) at a high concentration is produced. Separately prepared styrene-acrylonitrile copolymer (C-1-1) and the butadiene-styrene-acrylonitrile graft copolymer particles (C-2-1) (corresponding to the rubbery polymer particles (C-2)) are kneaded and diluted to adjust the concentrations of the rubbery polymer particles (C-2) and the polymer matrix (C-1) to desired values. Hereinafter, specific examples of the preparation method will be described.

[0156] - Preparation of Resin (C1) - To 122 parts by mass of a polybutadiene rubber latex (average particle diameter 0.280 μm, solid content 37% by mass), 0.1 part by mass of tertiary dodecyl mercaptan and 23 parts by mass of deionized water were added. After replacing the gas phase with nitrogen, the temperature was raised to 55°C. Then, while raising the temperature to 70°C over 1.5 hours, an aqueous solution prepared by dissolving 0.2 part by mass of sodium formaldehyde sulfoxylate, 0.004 part by mass of ferrous sulfate, and 0.04 part by mass of disodium ethylenediaminetetraacetate in 50 parts by mass of deionized water was added dropwise to a monomer mixture solution consisting of 14 parts by mass of acrylonitrile, 37 parts by mass of styrene, 0.5 part by mass of tertiary dodecyl mercaptan, and 0.15 part by mass of cumene hydroperoxide over 4 hours. After adding 0.02 part by mass of cumene hydroperoxide after the addition was completed, the polymerization reaction was completed while controlling the reaction vessel at 70°C for another 1 hour. To the mixture of the styrene-acrylonitrile copolymer and the butadiene-styrene-acrylonitrile graft copolymer thus obtained, an antifoaming agent made of silicone resin (manufactured by Momentive Performance Materials Japan LLC, product name TSA737) and a phenolic antioxidant emulsion (manufactured by Chukyo Yushi Co., Ltd., product name L-673) were added. Then, deionized water was added and adjusted so that the solid content concentration became 10% by mass, and it was heated to 70°C. Then, an aqueous aluminum sulfate solution was added to cause coagulation, and solid-liquid separation was performed using a screw press. The water content at this time was 10% by mass. This was dried to obtain a resin (C-2-1) containing butadiene-styrene-acrylonitrile graft copolymer particles at a high concentration. As a result of composition analysis, the composition ratio of the above resin (C-2-1) was 17% by mass of acrylonitrile, 45% by mass of butadiene, and 38% by mass of styrene. Also, the butadiene-styrene-acrylonitrile graft copolymer was in the form of particles like the polybutadiene rubber latex, and its average particle diameter was 0.30 μm. On the other hand, a monomer mixture consisting of 63 parts by mass of styrene, 22 parts by mass of acrylonitrile, and 15 parts by mass of ethylbenzene was continuously fed into a fully mixed reactor equipped with a stirrer, and a polymerization reaction was carried out at 150°C with a residence time of 2 hours. The obtained polymerization solvent was continuously fed into an extruder, and unreacted monomers and solvents were recovered by a devolatilization extruder to obtain a styrene-acrylonitrile copolymer (C-1-1). As a result of composition analysis using a Fourier transform infrared spectrophotometer (FT-IR) (manufactured by JASCO Corporation), the composition of the copolymer (C-1-1) was 30% by mass of acrylonitrile and 70% by mass of styrene. The resin (C-2-1) containing butadiene-styrene-acrylonitrile graft copolymer particles (rubbery polymer particles (C-2)) obtained by the above procedure at a high concentration and the styrene-acrylonitrile copolymer (C-1-1) were extruded and kneaded using a twin-screw extruder and pelletized to obtain an ABS resin (C1) as a pellet-shaped ABS resin. The composition and physical properties of the obtained ABS resin (C1) are shown in Table 3.

[0157] - Preparation of ABS resin (C2) - The feed amounts of the respective monomers and the polymerization conditions were adjusted, and after preparing the resin (C-2-1) by the same procedure as the above ABS resin (C1), 90 parts by mass of the ABS resin and 10 parts by mass of the styrene-acrylonitrile-N-phenylmaleimide copolymer were melt-kneaded and pelletized in a twin-screw extruder to obtain the pelletized ABS-based compound resin, ABS resin (C2). The composition and physical properties of the obtained ABS resin (C2) are shown in Table 3.

[0158]

Table 3

[0159] <Production Example of Core-Shell Rubber-Like Polymer Particles (D)> -Preparation of Rubber-Like Polymer Particles (D1)- Into a pressure-resistant container equipped with a stirrer, 200 parts by mass of pure water, 0.002 parts by mass of disodium ethylenediaminetetraacetate, 0.0012 parts by mass of ferrous sulfate, 0.008 parts by mass of disodium ethylenediaminetetraacetate, and 0.03 parts by mass of sodium polyoxyethylene alkyl ether phosphate were charged. After deoxidation, 100 parts by mass of butadiene, 0.05 parts by mass of sodium formaldehyde sulfoxylate, and 0.2 parts by mass of paramethane hydroperoxide were added. Then, 1.4 parts by mass of sodium polyoxyethylene alkyl ether phosphate was added dropwise over 6 hours. After that, the reaction solution was maintained at 50 °C for 124 hours at a pH of 6.5 to 7.5 to obtain a diene-based rubber latex with a conversion rate of 98% by weight and an average particle diameter of 0.18 μm. Subsequently, while maintaining the obtained rubber latex (about 71 parts by solid content) at 60°C, 55 parts by mass of methyl methacrylate as a monomer and 5 parts by mass of acrylic acid (n-butyl) were added over 1 hour. Also, simultaneously with the addition of the above monomers, the addition of 0.09 parts by mass of t-butyl hydroperoxide and 0.1 parts by mass of sodium formaldehyde sulfoxylate was started, and then the total amount was added over 2 hours while maintaining the pH in the reaction solution at 6.5 - 7.5 and the temperature at about 60°C. Further, the reaction solution was held at about 60°C for 1 hour to prepare a graft copolymer latex with an average particle diameter of 200 nm. After adding 1 part by mass of Irganox 1076 as an antioxidant, it was coagulated with an aqueous calcium chloride solution, washed with water, dehydrated and dried to obtain rubber-like polymer particles (D1) as a powder. The composition and physical properties of the rubber-like polymer particles (D1) are shown in Table 4.

[0160] - Preparation of rubber-like polymer particles (D2)- The feed amounts of each monomer and the polymerization conditions were adjusted, and D2 was prepared in the same procedure as D1 above. The composition and physical properties of the obtained rubber-like polymer particles (D2) are shown in Table 4.

[0161]

Table 4

[0162] In addition to the compositions shown in Table 4 above, the following products were used in the examples as core-shell type rubber-like polymer particles (D) containing (meth)acrylate monomer units (d1) and conjugated diene monomer units (d2). (D3) Metabrene C-223A manufactured by Mitsubishi Chemical Corporation (D4) Metabrene E-875A manufactured by Mitsubishi Chemical Corporation

[0163] <Production Example of Impact-Resistant Styrene-Based Resin (E)> - Preparation of Impact-Resistant Styrene-Based Resin (E1)- Using a polymerization apparatus in which three laminar flow reactors (1.5 liters each) equipped with stirrers were connected in series and then an extruder with a two-stage vent was arranged, an impact-resistant styrene resin (E1) (hereinafter referred to as resin (E1)) was produced. 82.4 parts by mass of styrene, 9.0 parts by mass of ethylbenzene, 8.6 parts by mass of Ube Industries' Hycis butadiene rubber 13HB as a rubbery polymer (E-2), and 0.02 parts by mass of 1,1-bis(t-butylperoxy)cyclohexane were charged into a raw material tank equipped with a stirrer. After dissolving the rubber component with a stirrer, this raw material solution was supplied to the reactor at a rate of 0.75 liters / hr. Polymerization was carried out at a temperature of 110 - 120°C in the first reactor, 120 - 130°C in the second reactor, and 140 - 150°C in the third reactor. Also, the extruder temperature was 210 - 240°C, the vacuum degree was 3 kPa, and the total solid content in the polymerization liquid exiting the final reactor was 70.5% by mass. The average particle diameter of the rubbery polymer particles (E-2) was controlled by adjusting the rotation speed of the stirrer in the first laminar flow reactor to 110 rpm. The composition and properties of the obtained resin (E1) are shown in Table 5.

[0164] - Preparation of Resin (E2)- Using Ube Industries' Hycis butadiene rubber 15HB as a rubbery polymer (E-2), resin (E2) was obtained with the composition and physical properties shown in Table 5 by the same procedure as above.

[0165] - Preparation of Resin (E3)- Using styrene, methyl methacrylate, butyl acrylate as monomers and Asahi Kasei's styrene-butadiene copolymer 625A as a rubbery polymer (E-2), resin (E3) was obtained with the composition and physical properties shown in Table 5 by the same procedure as above.

[0166]

Table 5

[0167] <Styrene-based Elastomer (F) Used in Examples> In the examples of this specification, the following two types were used as the styrene-based elastomer (F). (F1) Asahi Kasei's styrene-butadiene block copolymer Asaflex 835 (F2) Asahi Kasei's styrene-butadiene block copolymer Toughprene 125 <Acrylic elastomer (G) used in the examples> In the examples of this specification, the following three types were used as the acrylic elastomer (G). (G1) Kuraray's Clarity LA4285 (G2) Kuraray's Clarity LA2270 (G3) Kuraray's Clarity LA2250 Resins (G1) to (G3), which are any of the above acrylic elastomers (G), are poly(methyl methacrylate-b-butyl acrylate-b-methyl methacrylate) triblock copolymers and have the properties shown in Table 6 below.

[0168]

Table 6

[0169] <Monohydric alcohol having 10 or more carbon atoms used in the examples> In the examples of this specification, the following alcohol species were used as the monohydric alcohol having 10 or more carbon atoms. Fine Oxocol 180 (5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)-1-octanol) manufactured by Nissan Chemical Industries, Ltd. was used. Emulgen 109P (polyoxyethylene (9) lauryl ether monoalcohol) manufactured by Kao Corporation was used.

[0170] <<Manufacturing examples of styrene resin composition and foamed extrusion sheet>> The following shows the detailed manufacturing methods of the styrene resin composition and the foamed extrusion sheet. [Example 1] -Manufacture of styrene resin composition- As the styrene-(meth)acrylic resin (A), 93.0 parts by mass of the resin (A1) described in Table 1, as the (meth)acrylic resin (B), 7.0 parts by mass of the resin (B1) described in Table 2, and 0.12 parts by mass of Fine Oxocol 180 were dry-blended at a ratio, and kneaded and extruded using a twin-screw extruder TEM26SS manufactured by Shibaura Machine Co., Ltd., and through pelletizing, a styrene resin composition [1] was obtained as a pelletized resin. The screw rotation speed was 150 rpm, the cylinder temperature was 180 - 230 °C, and the feed rate was 10 kg / h. The resin temperature was 250 - 260 °C. The evaluation results of the properties and physical properties of the styrene resin composition [1] are shown in Table 7-1.

[0171] - Production of Extruded Sheet - The styrene resin composition [1] obtained above was supplied to an extruder having a vacuum vent capable of nitrogen purging. The maximum cylinder temperature of the extruder was set at 250 °C. The resin composition extruded from the T-die was wound up with a mirror-finished metal roll, and by adjusting the winding speed and the resin discharge amount, an extruded sheet [1] with a thickness of 0.25 mm was produced. The evaluation results of the obtained extruded sheet [1] are shown in Table 7-1.

[0172] - Production of Foamed Extruded Sheet - 100 parts by mass of the styrene resin composition [1] obtained above and 1.0 part by mass of talc (High Filler #12 manufactured by Matsumura Sangyo Co., Ltd.) as the inorganic fine particles (H) were dry-blended at a mass ratio and supplied to the extruder. The maximum cylinder temperature of the extruder was set at 250 °C. To the melt-kneaded resin composition, 4.0 parts by mass of a mixed butane with a mass ratio of isobutane / normal butane of 65 / 35 as a foaming agent was press-fitted with respect to 100 of the styrene resin composition [1], extruded cylindrically from an annular die, and foamed. After blowing air onto the obtained cylindrical foam for cooling, through a cooling process using a cooling mandrel, the cylindrical foam was cut open in the extrusion direction to obtain a foamed extruded sheet [1]. The evaluation results of the obtained foamed extruded sheet [1] and the evaluation results of a foamed container formed by secondary molding of the foamed extruded sheet [1] are shown in Table 7-1.

[0173] [Examples 2 - 34] Styrene resin compositions [2] to

[34] , extruded sheets [2] to

[34] , and foamed extruded sheets [2] to

[34] were obtained in the same manner as in Example 1 except that the formulation was changed as shown in Table 7 below. The evaluation results of the obtained styrene resin compositions [2] to

[34] , extruded sheets [2] to

[34] , foamed extruded sheets [2] to

[34] , containers formed by secondary molding of the extruded sheets, and containers formed by secondary molding of the foamed extruded sheets are shown in Tables 7-1 to 7-3.

[0174]

Table 7-1

[0175]

Table 7-2

[0176]

Table 7-3

[0177] [Examples 35 to 42] Styrene resin compositions

[35] to

[42] and extruded sheets

[35] to

[42] were obtained in the same manner as in Example 1 except that the formulation was changed as shown in Table 8 below. The evaluation results of the obtained styrene resin compositions

[35] to

[42] , extruded sheets

[35] to

[42] , and containers formed by secondary molding of the extruded sheets are shown in Table 8.

[0178]

Table 8

[0179] [Comparative Examples 1 to 3] Resin compositions, extruded sheets, foamed extruded sheets, containers formed by molding the extruded sheets, and containers formed by molding the foamed extruded sheets were obtained in the same manner as in Example 1 except that the formulation was changed as shown in Table 9 below. The evaluation results of the obtained resin compositions, extruded sheets, foamed extruded sheets, and containers formed by secondary molding of each sheet are shown in Table 9.

[0180]

Table 9

Industrial Applicability

[0181] The styrene resin composition obtained in the present invention is excellent in heat resistance, transparency, rigidity, heat oil resistance and appearance. Therefore, the styrene resin composition of the present invention can be widely used in extrusion molding, non-foamed sheets or foamed sheets, food packaging containers using them, or molded products by injection molding (electrical product parts, toys, daily necessities, various industrial parts), etc. It is particularly useful in packaging materials compatible with microwave oven heating cooking and plays a great role in the industrial world.

Claims

1. 40 to 99% by mass of a styrene-(meth)acrylic acid resin (A) having a styrene monomer unit (a1) and 2 to 17% by mass of a (meth)acrylic acid monomer unit (a2-1), 1 to 60% by mass of a (meth)acrylic resin (B) having a (meth)acrylic acid ester monomer unit (b1), One or more selected from the group consisting of a (meth)acrylonitrile-diene-styrene resin (C) containing a styrene monomer unit (c1), a conjugated diene monomer unit (c2), and a (meth)acrylonitrile monomer unit (c3), and core-shell type rubber-like polymer particles (D) containing a (meth)acrylic acid ester monomer unit (d1) and a conjugated diene monomer unit (d2), a styrene resin composition, The weight average molecular weight (Mw) of the (meth)acrylic resin (B) is in the range of 50,000 to 900,000, The styrene resin composition is divided into a high molecular weight component of 1,000,000 or more and a molecular weight component of less than 1,000,000, and the high molecular weight component of 1,000,000 or more is 1.0% by mass or less based on the total amount of the styrene resin composition.

2. The styrene-(meth)acrylic acid resin (A) contains the styrene monomer unit (a1), the (meth)acrylic acid monomer unit (a2-1), and a (meth)acrylic acid ester monomer unit (a2-2), and the styrene resin composition according to claim 1.

3. The styrene-(meth)acrylic acid resin (A) has the styrene monomer unit (a1), the (meth)acrylic acid monomer unit (a2-1), and a (meth)acrylic acid ester monomer unit (a2-2) as essential components, Based on the whole styrene-(meth)acrylic acid resin (A), the (meth)acrylic acid monomer unit (a2-1) is contained in an amount of 2 to 30% by mass, and the (meth)acrylic acid ester monomer unit (a2-2) is contained in an amount of 1 to 20% by mass, and the styrene resin composition according to claim 1 or 2.

4. The content of all (meth)acrylic acid ester monomer units contained in the styrene resin composition is 15 to 50% by mass based on the total amount of the styrene resin composition, and the styrene resin composition according to claim 1 or 2.

5. The (meth)acrylic resin (B) is a methyl methacrylate-methyl acrylate copolymer and contains 0.5 to 15% by mass of methyl acrylate monomer units based on the total amount of the copolymer. The styrenic resin composition according to claim 1 or 2.

6. The styrenic resin composition according to claim 1 or 2, further containing one or more selected from the group consisting of an impact-resistant styrenic resin (E) containing styrenic monomer units (e1) and conjugated diene monomer units (e2), a styrenic elastomer (F), and an acrylic elastomer (G).

7. The styrenic resin composition according to claim 1 or 2, further containing the (meth)acrylonitrile-diene-styrenic resin (C) and an acrylic elastomer (G).

8. The styrenic resin composition according to claim 1 or 2, further containing the core-shell rubbery polymer particles (D).

9. The styrenic resin composition according to claim 1 or 2, further containing inorganic particles (H) in an amount of 0.05 to 3.0% by mass based on the total amount of the styrenic resin composition.

10. An extruded sheet formed by molding the styrenic resin according to claim 1 or 2.

11. A molded article formed by injection molding the styrenic resin according to claim 1 or 2.

12. A container formed by secondary molding the extruded sheet according to claim 10.

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