Styrene-based resin composition and molded article

Abstract

To provide a styrene-based resin composition that reduces environmental impact and exhibits excellent transparency and color. [Solution] According to the present invention, a styrene resin composition is provided which contains styrene resin A and terpene resin B, and when molded into a 4 mm thick plate, the haze measured in accordance with JIS K-7136 is 1.5% or less, and the yellow index measured in accordance with JIS Z-8722 is 10.0 or less.

Description

【Technical Field】 , , , , , , 【0006】 , , 【0005】 , , 【0007】 , , 【0001】 The present invention relates to a styrenic resin composition and a molded article. 【Background Art】 【0002】 The present invention relates to a resin composition excellent in transparency and hue while being compounded with biomass, and a molded article obtained from the resin composition. 【0003】 Styrenic resins are used for a wide variety of applications due to their moldability and mechanical strength. In particular, styrenic resins with high transparency have a wide range of applications such as sundry goods, transparent food containers, packaging materials, and OA equipment. Also, biomass raw materials have attracted attention from the perspective of reducing environmental impact, and the development of composite materials of styrenic resins and natural-derived raw materials has been underway. For example, Patent Document 1 discloses a styrenic resin compounded with a terpene resin. 【Prior Art Documents】 【Patent Documents】 【0004】 【Patent Document 1】 Japanese Patent Application Laid-Open No. 2022-129115 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0005】 However, while it is possible to reduce the environmental impact, the transparency and hue required for molded articles for specific applications such as resin sundry goods, transparent food containers, packaging materials, and OA equipment have not been obtained. 【0006】 The present invention has been made in view of the above circumstances, and provides a styrenic resin composition capable of reducing the environmental impact and excellent in transparency and hue. 【Means for Solving the Problems】 【0007】 As a result of diligent research to solve the above problems, the inventors of the present invention have found that the above problems can be solved by including predetermined amounts of styrene resin and terpene resin, and by having the haze and yellow index within predetermined ranges, and have completed the present invention. 【0008】 The present invention provides the following: [1] A styrene resin composition containing styrene resin A and terpene resin B, wherein when molded into a 4 mm thick plate, the haze measured on the plate in accordance with JIS K-7136 is 1.5% or less, and the yellow index measured on the plate in accordance with JIS Z-8722 is 10.0 or less. [2] The styrene resin composition according to claim 1, wherein the content of the terpene resin B in 100% by mass of the styrene resin composition is 1 to 50% by mass. [3] The styrene-based resin composition according to claim 1 or claim 2, wherein the terpene-based resin B comprises a terpene phenol resin. [4] The styrene-based resin composition according to claim 3, wherein the terpene phenol resin comprises a hydrogenated terpene phenol resin. [5] The styrene-based resin composition according to any one of claims 1 to 4, wherein the Vicat softening temperature is 75°C or higher. [6] A molded article obtained by molding a styrene-based resin composition according to any one of claims 1 to 5. [Effects of the Invention] 【0009】 According to the present invention, it is possible to provide a styrene-based resin composition that can reduce environmental impact and has excellent transparency and color. [Brief explanation of the drawing] 【0010】 [Figure 1] Figure 1 is a diagram illustrating the shape of a box-shaped molded product for moldability testing. [Modes for carrying out the invention] 【0011】 Embodiments of the present invention will be described below. The various features shown in the embodiments below can be combined with each other. Furthermore, each feature can constitute an invention independently. In addition, any element not specified in the claims in the embodiments below is an optional element and can be omitted. Any number of zeros (for example, one or two) may be added to the end of the numerical values ​​disclosed in the following description. For example, one or two zeros may be added after "1.4" to make it "1.40" or "1.400". 【0012】 1. Styrene resin composition A styrene-based resin composition according to one embodiment of the present invention comprises a styrene-based resin A and a terpene-based resin B. 【0013】 The styrene-based resin composition contains terpene resin B. From the viewpoint of reducing environmental impact, a higher lower limit for the content of terpene resin B is preferable, but it is preferably 1% by mass or more, and more preferably 10% by mass or more, per 100% by mass of the styrene-based resin composition. On the other hand, from the viewpoint of heat resistance and other factors, the content of terpene resin B is preferably 50% by mass or less, and more preferably 30% by mass or less, per 100% by mass of the styrene-based resin composition. The content of terpene resin B is preferably 1 to 50% by mass, more preferably 10 to 30% by mass, of 100% by mass of the styrene resin composition. Specifically, for example, it may be 1, 5, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 35, 40, 45, or 50% by mass, and may be within the range of any two of the values ​​exemplified here. When two or more terpene resins are used in combination, the content (or percentage) of the terpene resins is based on the total amount of terpene resins used in combination. 【0014】 The styrene resin composition contains styrene resin A. The content of styrene resin A is preferably 50 to 99% by mass, and more preferably 70 to 90% by mass. When this range is met, environmental impact reduction and heat resistance are excellent. Specifically, the content of styrene resin A is, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 99% by mass of 100% by mass of the styrene resin composition, and may be within the range of any two of the values ​​exemplified here. When two or more types of styrene resins are used in combination, the content (or percentage) of the styrene resins is based on the total amount of styrene resins used in combination. 【0015】 The biomass content of the styrene-based resin composition is, for example, 0.5% or more, preferably 3% or more, and more preferably 6.5% or more. A higher biomass content reduces the environmental burden. Specifically, the biomass content can be, for example, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 15, 20, 25, 30, or 35%, and may be within the range of any two of the values ​​exemplified here. The biomass content (in %) is determined by the ratio of the dry mass of biomass-derived components to the total dry mass of the styrene-based resin composition. 【0016】 The styrene-based resin composition has a melt mass flow rate (MFR) measured in accordance with JIS K-7210, which is, for example, 0.8 g / 10min or higher, preferably 2.0 to 30.0 g / 10min. When this range is met, the composition exhibits excellent fluidity during molding. Specifically, the MFR may be, for example, 0.8, 0.9, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 8.0, 9.0, 10.0, 15.0, 20.0, 25.0, or 30.0 g / 10min, and may also be within the range of any two of the values ​​exemplified here. 【0017】 When the styrene resin composition is formed into a 4-mm-thick plate, the Vicat softening temperature measured for the plate in accordance with JIS K-7206 is, for example, 65°C or higher, preferably 75°C or higher, and more preferably 80°C or higher. When within such a range, it has excellent heat resistance. Specifically, the Vicat softening temperature is, for example, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120°C, and it may also be within the range between any two of the values exemplified herein. 【0018】 When the styrene resin composition is formed into a 4-mm-thick plate, the total light transmittance measured for the plate in accordance with JIS K-7136 is, for example, 80% or higher. When within such a range, it has excellent transparency. Specifically, the total light transmittance is, for example, 80, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100%, and it may also be within the range between any two of the values exemplified herein. 【0019】 When the styrene resin composition is formed into a 4-mm-thick plate, the haze measured for the plate in accordance with JIS K-7136 is 1.5% or less, preferably 1.0% or less. When within such a range, it has excellent transparency. Specifically, the haze is, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5%, and it may also be within the range between any two of the values exemplified herein. 【0020】 When the styrene resin composition is formed into a 4-mm-thick plate, the yellow index measured for the plate in accordance with JIS Z-8722 is 10 or less. When within such a range, the hue is excellent. Specifically, the yellow index is, for example, 0.1, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, and it may be within the range between any two of the values exemplified herein. 【0021】 When the styrene resin composition is molded into the box-shaped molded product shown in Fig. 1 (dimensions (outer dimensions): 60 mm in length, 130 mm in width, 45 mm in depth, 2 mm in thickness) using an injection molding machine (manufactured by Japan Steel Works, Ltd., J100E-P) at a cylinder temperature of 220°C and a mold temperature of 40°C, the cooling time required until the molded product, which is a 2-mm-thick box-shaped molded product, can be removed from the mold is, for example, 20 seconds or less, preferably 15 seconds or less. When within such a range, the moldability is excellent. Specifically, the cooling time is, for example, 1, 5, 10, 15, 20 seconds, and it may be within the range between any two of the values exemplified herein. 【0022】 <Styrene-based resin A> Styrene-based resin A is obtained by radical polymerization of an aromatic vinyl compound-based monomer. As the polymerization method, it can be produced by known methods, for example, bulk polymerization method, bulk / suspension two-stage polymerization method, solution polymerization method, etc. 【0023】 Aromatic vinyl monomers are monocyclic or polycyclic aromatic vinyl monomers, such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 3,4-dimethylstyrene, 3,5-dimethylstyrene, p-ethylstyrene, m-ethylstyrene, o-ethylstyrene, p-tert-butylstyrene, 1-vinylnaphthalene, 2-vinylnaphthalene, 1,1-diphenylethylene, isopropenylbencene (α-methylstyrene), isopropenyltoluene, isopropenylethylbenzene, isoprop The material is penylpropylbenzene, isopropenylbutylbenzene, isopropenylpentylbenzene, isopropenylhexylbenzene, isopropenyloctylbenzene, etc., either alone or in mixtures of two or more. Preferably, it is styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 3,4-dimethylstyrene, 3,5-dimethylstyrene, p-ethylstyrene, m-ethylstyrene, o-ethylstyrene, p-tert-butylstyrene, either alone or in mixtures of two or more. More preferably, it is styrene. 【0024】 Styrene resin A preferably contains 20% to 100% by mass of styrene monomer units in 100% by mass of polymer. Specifically, the content of styrene monomer units in 100% by mass of polymer in styrene resin A is, for example, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100% by mass, and may be within the range of any two of the values ​​exemplified here. In one embodiment, styrene resin A may be a polymer of styrene monomers (styrene polymer). In another embodiment, styrene resin A may be a copolymer having styrene monomer units and (meth)acrylic monomer units (styrene-(meth)acrylic copolymer). 【0025】 The styrene polymer may be a homopolymer of styrene monomers obtained by polymerizing only one type of styrene monomer, or it may be a copolymer obtained by polymerizing only two or more types of styrene monomers. Furthermore, the styrene polymer preferably contains 95% by mass or more, and more preferably (substantially) 100% by mass, of styrene monomer units in 100% by mass of the styrene polymer. Specifically, the content of styrene monomer units in 100% by mass of the styrene polymer may be, for example, 95, 96, 97, 98, 99, 99.5, or 100% by mass, and may be within the range of any two of the values ​​exemplified here. Note that if two or more types of styrene monomer units are used, this content is the total mass. From the viewpoint of minimizing dimensional changes, the styrene polymer is preferably a homopolymer of styrene. 【0026】 (Meth)acrylic monomer units are (meth)acrylic acid monomer units or (meth)acrylic acid ester monomer units. Styrene-(meth)acrylic copolymers are styrene-(meth)acrylic acid copolymers or styrene-(meth)acrylic acid ester copolymers. 【0027】 A styrene-(meth)acrylic acid copolymer is a copolymer having styrene monomer units and (meth)acrylic acid monomer units. The styrene-(meth)acrylic acid copolymer preferably contains 1 to 20% by mass, more preferably 5 to 13% by mass, of (meth)acrylic acid monomer units per 100% by mass of the styrene-(meth)acrylic acid copolymer. Specifically, the content of (meth)acrylic acid monomer units per 100% by mass of the styrene-(meth)acrylic acid copolymer is, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20% by mass, and may be within the range of any two of the values ​​exemplified here. Note that if two or more types of (meth)acrylic acid monomer units are used, this content is the total mass. 【0028】 The styrene-(meth)acrylic acid copolymer preferably contains 80 to 99% by mass, more preferably 85 to 95% by mass, of styrene monomer units in 100% by mass of the styrene-(meth)acrylic acid copolymer. Specifically, the content of styrene monomer units in 100% by mass of the styrene-(meth)acrylic acid copolymer is, for example, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99% by mass, and may be within the range of any two of the values ​​exemplified here. Note that if two or more types of styrene monomer units are used, this content is the total mass of those units. 【0029】 A styrene-(meth)acrylic acid ester copolymer is a copolymer having styrene monomer units and (meth)acrylic acid ester monomer units. The styrene-(meth)acrylic acid ester copolymer preferably contains 20 to 80% by mass, and more preferably 40 to 70% by mass, of (meth)acrylic acid ester monomer units in 100% by mass of the styrene-(meth)acrylic acid ester copolymer. The content of (meth)acrylic acid ester monomer units is specifically, for example, 16, 20, 25, 30, 35, 40, 45, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 75, and 80% by mass of the styrene-(meth)acrylic acid ester copolymer, and may be within the range of any two of the values ​​exemplified here. Note that if two or more types of (meth)acrylic acid ester monomer units are used, this content is the total mass of those units. 【0030】 The styrene-(meth)acrylic acid ester copolymer preferably contains 20 to 80% by mass, more preferably 30 to 50% by mass, of styrene monomer units in 100% by mass of the styrene-(meth)acrylic acid ester copolymer. Specifically, the content of styrene monomer units in 100% by mass of the styrene-(meth)acrylic acid ester copolymer is, for example, 20, 25, 30, 35, 40, 45, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 75, or 80% by mass, and may be within the range of any two of the values ​​exemplified here. Note that if two or more types of styrene monomer units are used, this content is the total mass of those units. 【0031】 (Meth)acrylic acid monomer units are constituent units of polymers derived from (meth)acrylic acid monomers. (Meth)acrylic acid monomers are acrylic acid or methacrylic acid. (Meth)acrylic acid monomers may be used alone or in combination of two or more types. 【0032】 (Meth)acrylic acid ester monomer units are constituent units of polymers derived from (meth)acrylic acid ester monomers. (Meth)acrylic acid ester monomers are acrylic acid esters or methacrylic acid esters. More specifically, (meth)acrylic acid ester monomers include alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, isoamyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and lauryl (meth)acrylate; and alkyl esters such as phenyl (meth)acrylate and benzyl (meth)acrylate. Examples include yl methacrylate; cycloalkyl methacrylates such as cyclohexyl (meth)acrylate, 4-t-butylcyclohexyl (meth)acrylate, 2-norbornyl (meth)acrylate, isobornyl (meth)acrylate, adamantan-1-yl (meth)acrylate, 2-methyladamantan-2-yl (meth)acrylate, 2-ethyl-2-adamantyl (meth)acrylate, and tricyclodecanyl (meth)acrylate; glycidyl (meth)acrylate; and dicyclopentanyl (meth)acrylate. The (meth)acrylate ester monomer is preferably an alkyl (meth)acrylate, and more preferably methyl methacrylate. The (meth)acrylate ester monomer may be used alone or in combination of two or more types. 【0033】 The molecular weight of styrene resin A is preferably 50,000 to 500,000, and more preferably 100,000 to 400,000, in terms of weight-average molecular weight (Mw). Specifically, for example, it may be 50,000, 100,000, 150,000, 200,000, 250,000, 300,000, 350,000, 400,000, 450,000, or 500,000, and may also be within the range of any two of the values ​​exemplified here. By using such a range, a styrene resin composition with excellent fluidity and heat resistance can be obtained. The weight-average molecular weight of styrene resin A can be controlled by the reaction temperature of the polymerization process, residence time, type and amount of polymerization initiator added, type and amount of chain transfer agent added, type and amount of solvent used during polymerization, etc. 【0034】 The weight-average molecular weight can be measured using gel permeation chromatography (GPC) under the following conditions. GPC model: Shodex GPC-101 manufactured by Showa Denko Corporation Column: PLgel 10μm MIXED-B, manufactured by Polymer Laboratories, Inc. Mobile phase: tetrahydrofuran Sample concentration: 0.2% by mass Temperature: Oven 40°C, Inlet 35°C, Detector 35°C Detector: Differential refractometer The molecular weight of this invention was calculated by determining the molecular weight at each elution time from the elution curve of monodisperse polystyrene, and then calculating it as the molecular weight in terms of polystyrene equivalent. 【0035】 Known styrene polymerization methods for styrene resin A include bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. In terms of quality and productivity, bulk polymerization and solution polymerization are preferred, and continuous polymerization is preferable. Examples of solvents that can be used include alkylbenzenes such as benzene, toluene, ethylbenzene, and xylene, ketones such as acetone and methyl ethyl ketone, and aliphatic hydrocarbons such as hexane and cyclohexane. 【0036】 In continuous polymerization, the polymerization reaction is first controlled by adjusting the polymerization temperature and other means to achieve the target molecular weight, molecular weight distribution, and reaction conversion rate using known fully mixed stirring tanks or tower reactors in the polymerization step. The polymerization solution containing the polymer that exits the polymerization step is transferred to the defoliation step, where unreacted monomers and polymerization solvent are removed. The defoliation step consists of a vacuum defoliation tank with a heater or a defoliation extruder with a vent. The molten polymer that exits the defoliation step is transferred to the granulation step. In the granulation step, the molten resin is extruded in strand form from a porous die and processed into pellets using a cold-cut method, air-hot-cut method, or underwater-hot-cut method. 【0037】 During the polymerization of styrene resin A, polymerization initiators and chain transfer agents can be used as needed. As polymerization initiators, radical polymerization initiators are preferred, including well-known and conventional peroxyketals such as 1,1-di(t-butylperoxy)cyclohexane, 2,2-di(t-butylperoxy)butane, 2,2-di(4,4-di-t-butylperoxycyclohexyl)propane, and 1,1-di(t-amylperoxy)cyclohexane; hydroperoxides such as cumene hydroperoxide and t-butyl hydroperoxide; alkyl peroxides such as t-butylperoxyacetate and t-amylperoxyisononanoate; and t-butylcumylperoxide, di-t-butylperoxide, dicumylperoxide, and di-t-hexylperoxide. Examples of peroxy esters include dialkyl peroxides such as t-butyl peroxyacetate, t-butyl peroxybenzoate, and t-butyl peroxyisopropyl monocarbonate, as well as peroxycarbonates such as t-butyl peroxyisopropyl carbonate and polyethertetrakis(t-butyl peroxycarbonate), and N,N'-azobis(cyclohexane-1-carbonitride), N,N'-azobis(2-methylbutyronitrile), N,N'-azobis(2,4-dimethylvaleronitrile), and N,N'-azobis[2-(hydroxymethyl)propionitrile]. One or more of these can be used in combination. Examples of chain transfer agents include aliphatic mercaptans, aromatic mercaptans, pentaphenylethane, α-methylstyrene dimer, and terpinolene. 【0038】 <Terpene-based resin B> Terpene resin B is a resin derived from terpenes obtained from plant essential oils such as pine and orange. Because it is a resin with a relatively high biomass content, it can be effectively used from the perspective of reducing carbon dioxide emissions in light of the growing environmental awareness of today. 【0039】 Terpene resin B is obtained by polymerizing terpene compounds that have a terpene as their basic skeleton, such as terpenes, monoterpenes, sesquiterpenes, and diterpenes, which are hydrocarbons containing the chemical formula isoprene as the main monomer component and their oxygen-containing derivatives. Specifically, these are terpene resins such as terpenephenol, which is a copolymer of a terpene compound and a phenol compound; hydrogenated terpenephenol, which is obtained by partially or completely hydrogenating terpenephenol; aromatically modified terpenes, which are obtained by copolymerizing a terpene compound and an aromatic compound; and hydrogenated aromatic terpenes, which are obtained by partially or completely hydrogenating terpenephenol. One type may be used, or two or more types may be used. 【0040】 The terpene compounds are not particularly limited, but examples include α-pinene, β-pinene, carvone, camphene, 2-carene, 3-carene, dipentene, d-limonene, myrcene, allo-cimene, ocimene, α-phellandrene, α-ionone, β-ionone, β-citronellene, α-terpinene, γ-terpinene, terpinolene, 1,8-cineole, 1,4-cineole, β-citronellol, α-terpineol, β-terpineol, γ-terpineol, etc. One of these may be used, or two or more may be used. All of these terpene compounds are of plant or animal origin, naturally biosynthesized, and are renewable resources. 【0041】 Terpene resin B preferably contains a terpene phenol resin and is a terpene phenol resin. Furthermore, terpene resin B preferably contains a hydrogenated terpene phenol resin and is more preferably a hydrogenated terpene phenol resin. When a hydrogenated terpene phenol resin is used, excellent transparency is obtained. 【0042】 The softening point of terpene resin B is, for example, 60°C to 170°C, preferably 100°C to 145°C. Specifically, for example, it is 100, 105, 110, 115, 120, 125, 130, 135, 140, 145°C, and may also be within the range of any two of the values ​​exemplified here. 【0043】 <Other additives> The styrene resin composition may contain other additives, such as plasticizers, spreading agents, solvents, ultraviolet absorbers, light stabilizers, stabilizers, colorants, dyes and pigments, organic fillers, color inhibitors, reinforcing agents, compatibilizers, crystallization accelerators, flame retardants, flame retardant aids, etc., as long as they do not impair the objectives of the present invention. It may also contain naturally derived materials other than terpene resin B as biomass. 【0044】 Biomass refers to renewable, biologically derived organic and inorganic resources, excluding fossil resources. Biomass includes organic biomass and / or inorganic biomass. Organic biomass is biomass mainly consisting of solid components derived from plants and / or algae. Inorganic biomass is biomass mainly consisting of solid components derived from aggregates of inorganic substances (such as calcium carbonate) in living organisms. The organic biomass in this embodiment is not particularly limited, but for example, wood flour, paper flour, charcoal, rice husks, tea husks, old rice flour, rice bran, okara (soy pulp), wheat bran, lees from sake, shochu, beer, wine, and soy sauce, starch, konjac by-products, lees from fruit tree peels or fruits, grasses including rice, wheat, and buckwheat, seaweed or algae, cotton fibers, palm fibers, or mixtures thereof can be suitably used. From the viewpoint of transparency and hue, hydrogenated rosin esters are preferred over terpene resins. The inorganic biomass used in this embodiment is not particularly limited, but for example, bones, eggshells, and seashells can be suitably used. 【0045】 In one embodiment, biomass other than terpene resin B is contained in 10, 5, or 1% by mass or less relative to the styrene resin composition. In another embodiment, the styrene resin composition according to the present invention does not contain biomass other than terpene resin B. 【0046】 These addition methods are not particularly limited and can be done using known methods. Methods of addition during the raw material preparation, polymerization, and finishing processes in the production of styrene resin A or terpene resin B can be applied, as can methods of addition during the mixing of the resin composition using an extruder or molding machine. 【0047】 <Method for producing styrene-based resin compositions> Styrene-based resin compositions can be obtained by mixing raw materials such as styrene-based resin A and terpene-based resin B. The mixing method is not particularly limited, and known mixing techniques can be applied. For example, a uniform resin composition can be produced by pre-mixing various raw materials using a mixing device such as a mixer-type mixer, a V-type blender, and a tumbler-type mixer, and then melt-kneading the mixture. The melt-kneading device is also not particularly limited, but examples include Banbury-type mixers, kneaders, rolls, single-screw extruders, special single-screw extruders, and twin-screw extruders. Furthermore, there is also a method of adding other additives separately during the melt-kneading process using a melt-kneading device such as an extruder. 【0048】 <Molded products> A molded article according to one embodiment of the present invention is a molded article made of the above-mentioned styrene-based resin composition. Examples of molded articles include general merchandise, transparent food containers, packaging materials, office automation equipment, and the like. 【0049】 Molded products can be obtained by various molding methods. There are no particular limitations on the molding method, and known molding methods such as extrusion molding methods such as calender molding, hollow molding, extrusion foam molding, shape extrusion molding, laminate molding, inflation molding, T-die film molding, sheet molding, vacuum molding, and pressure molding, as well as injection molding methods such as injection molding, RIM molding, and injection foam molding, can be suitably used, but injection molding or sheet molding is preferred. [Examples] 【0050】 The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited thereto. 【0051】 The materials used in the examples and comparative examples are as follows: 【0052】 [Styrene resin A] (A-1) GPPS (Toyo Styrene HRM26, manufactured by Toyo Styrene Co., Ltd.) (A-2) Styrene-methyl methacrylate copolymer (Toyo MS MS-600, manufactured by Toyo Styrene Co., Ltd.) (A-3) The polymerization process was constructed by connecting a first reactor and a second reactor, both fully mixed stirred tanks, and a third reactor, a plug-flow type reactor with a static mixer, in series. The capacity of each reactor was 39 liters for the first reactor, 39 liters for the second reactor, and 16 liters for the third reactor. A raw material solution consisting of 75.4 parts by mass of styrene monomer, 6.9 parts by mass of methacrylic acid, 15.2 parts by mass of ethylbenzene, 2.5 parts by mass of 1-octanol, 0.14 parts by mass of polyoxyethylene lauryl ether (Emulgen 109P, manufactured by Kao Corporation), and 0.20 parts by mass of 1,1-di(t-butylperoxy)cyclohexane (Perhexa C, manufactured by NOF Corporation) was continuously supplied to the first reactor at a supply rate of 12.6 L / hr, and polymerization was carried out at temperatures of 125°C for the first reactor, 132°C for the second reactor, and 132-136°C for the third reactor. The obtained polymerization solution was introduced into a vacuum defloration tank with a preheater, consisting of two stages in series. Unreacted styrene, methacrylic acid, and ethylbenzene were separated, then the solution was extruded into strands, cooled, and cut to form pellets. The resin temperature in the first stage defloration tank was set to 160°C and the pressure in the vacuum defloration tank to 65 kPa, while the resin temperature in the second stage defloration tank was set to 230°C and the pressure in the vacuum defloration tank to 0.7 kPa. The weight-average molecular weight (Mw) of the obtained styrene-methacrylic acid copolymer was 300,000, and the methacrylic acid content was 10% by mass out of 100% by mass of the styrene-methacrylic acid copolymer. 【0053】 [Terpene resin B] (B-1) Hydrogenated terpene phenol resin (YS Polystar UH115, Yasuhara Chemical Co., Ltd.) Biomass content: 65%, softening point: 110-120℃ (B-2) Terpene phenol resin (YS Polystar TH130, Yasuhara Chemical Co., Ltd.) Biomass content: 65%, softening point: 125-135℃ (B-3) Aromatic-modified terpene resin (YS Resin TO125, Yasuhara Chemical Co., Ltd.) Biomass content: 70%, softening point: 120-125℃ (B-4) Hydrogenated aromatic modified terpene resin (Clearon M115, Yasuhara Chemical Co., Ltd.) Biomass content: 65%, softening point: 110–120°C 【0054】 [Rosin-based resin] Rosin ester: Ester gum AA-G, Arakawa Chemical Industries, Ltd. [Palm oil] Refined palm oil A, manufactured by Fuji Oil Co., Ltd., 100% biomass content. 【0055】 (Examples 1-7, Comparative Examples 1-5) Each component was pre-mixed in the proportions shown in Table 1 using a Henschel mixer (Mitsui Miike Chemical Co., Ltd., FM20B), and then supplied to a twin-screw extruder (Toshiba Machine Co., Ltd., TEM26SS) to form strands under conditions of cylinder temperature 200°C and supply rate 25 kg / h. After water cooling, the extruder was fed to a pelletizer to form pellets. The resulting pellets were injection molded, and the results of various measurements and property evaluations are shown in Table 1. 【0056】 <Measurement> [Meltmass Flowrate] The melt mass flow rate of the styrene-based resin composition was measured for the above pellets under conditions of 200°C and a 49N load, in accordance with JIS K-7210. 【0057】 [Vicat softening temperature] A 30mm x 20mm x 4mm thick plate was obtained by injection molding pellets using an injection molding machine (Toyo Machinery & Metal Co., Ltd., Ti80G2) at a cylinder temperature of 210°C and a mold temperature of 45°C. The Vicat softening temperature of the styrene-based resin composition was measured for the test specimen under conditions of a 50N load and a heating rate of 50°C / hr, in accordance with JIS K-7206. 【0058】 [Total light transmittance / haze] Pellets were injected using an injection molding machine (Toyo Machinery & Metal Co., Ltd., Ti80G2) at a cylinder temperature of 210°C and a mold temperature of 45°C to form 65mm x 50mm x 4mm thick plates, which were then used as test specimens. The total light transmittance and haze of the styrene-based resin composition were measured using a haze meter (Nippon Denshoku Industries Co., Ltd., NDH7000) in accordance with JIS K-7136. 【0059】 [Yellow Index (YI)] For the 65mm x 50mm x 4mm thick test specimens obtained by the molding method described above, the yellowness (YI) was measured according to JIS Z-8722 using a spectrophotometer (SE7700, manufactured by Nippon Denshoku Industries Ltd.). 【0060】 [Moldability (cooling time)] When pellets were injected using an injection molding machine (manufactured by Japan Steel Works Ltd., J100E-P) at a cylinder temperature of 220°C and a mold temperature of 40°C, the box-shaped molded product shown in Figure 1 (dimensions (outer dimensions): 60 mm long, 130 mm wide, 45 mm deep, 2 mm thick) was molded, and the cooling time required for the molded product to be demolded was measured. 【0061】 [Table 1]

Claims

[Claim 1] It contains styrene resin A and terpene resin B, A styrene-based resin composition in which, when molded into a 4 mm thick plate, the haze measured in accordance with JIS K-7136 is 1.5% or less, and the yellow index measured in accordance with JIS Z-8722 is 10.0 or less. [Claim 2] The styrene resin composition according to claim 1, wherein the content of the terpene resin B in 100% by mass of the styrene resin composition is 1 to 50% by mass. [Claim 3] The styrene-based resin composition according to claim 1, wherein the terpene-based resin B comprises a terpene phenol resin. [Claim 4] The styrene-based resin composition according to claim 3, wherein the terpene phenol resin comprises a hydrogenated terpene phenol resin. [Claim 5] The styrene-based resin composition according to claim 1, wherein the Vicat softening temperature is 75°C or higher. [Claim 6] A molded article obtained by molding a styrene-based resin composition according to any one of claims 1 to 5.