styrene-based resin composition

Abstract

To provide a styrenic resin composition that has high heat resistance and impact resistance and contains styrenic resin and liquid crystal polymer.SOLUTION: The present invention provides a styrenic resin composition that contains 20-70 pts.mass of styrenic resin A and 30-80 pts.mass of liquid crystal polymer B when the total of the styrenic resin A and the liquid crystal polymer B is 100 pts.mass.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a styrene-based resin composition having excellent heat resistance and impact resistance, which contains a styrene-based resin and a liquid crystal polymer. [Background technology]

[0002] Polymer alloy technology is known as a means of combining multiple resins to compensate for the shortcomings of each individual resin and even to create unprecedented functions. For example, Patent Document 1 discloses that the addition of a specific diglycidyl ether ester compound as a compatibilizer improves the compatibility between a thermoplastic resin such as polyethylene terephthalate and a liquid crystal polymer. Patent Document 2 also discloses that a thermoplastic resin with excellent fluidity and mechanical properties is obtained by combining a thermoplastic resin such as a polyester resin with a flow improver, and this is used as a resin composition for connectors. Patent Document 3 also discloses that a thermoplastic resin containing at least one of a styrene-based polymer and a liquid crystal polymer resin having a syndiotactic structure and an inorganic filler with a positive temperature coefficient of dielectric constant under specific conditions can be used to obtain a molded product with a large dielectric constant, a small dielectric loss tangent, and a small temperature coefficient of dielectric constant in the high-frequency range of 1 GHz or higher. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2017-214460 [Patent Document 2] JP 2007-234260 [Patent Document 3] JP 2003-342478 A Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a styrene-based resin composition containing a styrene-based resin and a liquid crystal polymer, which has excellent heat resistance and impact resistance. [Means for solving the problem]

[0005] As a result of investigations by the present inventors, it was found that a styrene-based resin composition containing 20 to 70 parts by mass of a styrene-based resin (A) and 30 to 80 parts by mass of a liquid crystal polymer (B), when the total of the styrene-based resin (A) and the liquid crystal polymer (B) is 100 parts by mass, has excellent heat resistance and impact resistance. That is, the present invention provides: (1) A styrene-based resin composition containing 20 to 70 parts by mass of styrene-based resin A and 30 to 80 parts by mass of liquid crystal polymer B, where the total of styrene-based resin A and liquid crystal polymer B is 100 parts by mass. (2) The styrene-based resin composition according to (1), wherein the styrene-based resin A is a homopolymer A1 of a styrene-based monomer a1, a copolymer A2 of a styrene-based monomer a1 and a monomer a2 having at least one of an ester group or a carboxyl group, or a rubber-containing styrene-based resin A3. (3) The styrene-based resin composition according to (2), wherein the monomer a2 having at least one of an ester group and a carboxyl group is (meth)acrylic acid or a (meth)acrylic acid ester. (4) The styrene-based resin composition according to (3), wherein the (meth)acrylic acid or (meth)acrylic acid ester is methacrylic acid or methyl methacrylate. (5) The styrene resin composition according to any one of (1) to (4), which has a deflection temperature under load of 100°C or more when measured in accordance with JIS K 7191 using a flatwise method under a stress of 1.8 MPa. (6) The styrene-based resin composition according to any one of (1) to (5), wherein the liquid crystal polymer B has a melting point of less than 240°C. (7) A molded article made of the styrene resin composition according to any one of (1) to (6). (8) A film made of the styrene resin composition according to any one of (1) to (6). Regarding. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a styrene-based resin composition containing a styrene-based resin and a liquid crystal polymer, which has excellent heat resistance and impact resistance. DETAILED DESCRIPTION OF THE INVENTION

[0007] <Terminology> In the present specification, for example, the expression "A to B" means A or more and B or less.

[0008] The following describes in detail the embodiments of the present invention. The present invention is not limited to these, and various modifications are possible without departing from the spirit of the invention. The various features shown in the following embodiments can be combined with each other. Furthermore, each feature can be an invention independently.

[0009] <Styrene-based resin composition> The styrene-based resin composition of the present embodiment contains a styrene-based resin (A) and a liquid-crystalline polymer (B). The styrene-based resin composition of the present embodiment may also contain another resin component (C) other than the styrene-based resin (A) and the liquid-crystalline polymer B, as long as the effects of the present invention are not impaired. The components contained in the styrene-based resin composition of the present embodiment will be described below.

[0010] The styrene-based resin composition of this embodiment contains 20 to 70 parts by mass, preferably 40 to 65 parts by mass, of the styrene-based resin (A) when the total of the styrene-based resin A and the liquid crystal polymer B is 100 parts by mass. Specifically, the content is, for example, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, or 70 parts by mass, and may be within a range between any two of the values ​​exemplified here. By keeping the content of the styrene-based resin (A) within the above range, the styrene-based resin composition has an excellent balance of heat resistance, impact resistance, and fluidity. Note that when a styrene-based resin (A) is used in combination, the amount of the styrene-based resin (A) used refers to the total amount of the styrene-based resin (A) used in combination.

[0011] Furthermore, the styrene-based resin composition of this embodiment contains 30 to 80 parts by mass, preferably 35 to 60 parts by mass, of the liquid crystal polymer (B) when the total of the styrene-based resin A and the liquid crystal polymer B is 100 parts by mass. Specifically, the content is, for example, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, or 80 parts by mass, and may be within a range between any two of the values ​​exemplified here. By keeping the content of the liquid crystal polymer (B) within the above range, the styrene-based resin composition has an excellent balance of heat resistance, impact resistance, and fluidity. Note that when the liquid crystal polymer (B) is used in combination, the amount of the liquid crystal polymer (B) used refers to the total amount of the liquid crystal polymer (B) used in combination.

[0012] <Styrene-based resin (A)> The styrene-based resin (A) according to this embodiment is obtained, for example, by radical polymerization and is atactic polystyrene. Preferably, the styrene-based resin (A) is a homopolymer (A1) of a styrene-based monomer (a1), a copolymer (A2) of the styrene-based monomer (a1) and a monomer (a2) having at least one of an ester group or a carboxyl group, or a rubber-containing styrene-based resin (A3). In one aspect, among these, a copolymer (A2) of the styrene-based monomer (a1) and a monomer (a2) having at least one of an ester group or a carboxyl group is preferred from the viewpoint of compatibility. These styrene-based resins (A) may be used alone or in combination of two or more.

[0013] <Homopolymer (A1) of styrene-based monomer (a1)> The homopolymer (A1) of the styrene-based monomer (a1) according to the present embodiment is obtained by polymerizing the styrene-based monomer (a1), which is an aromatic vinyl-based monomer. As the polymerization method, radical polymerization, anionic polymerization, and cationic polymerization are known, and the homopolymer (A1) produced by any of these methods can be used. Examples of aromatic vinyl monomers include styrene, α-methylstyrene, 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, isopropenylbenzene (α-methylstyrene), isopropenyltoluene, isopropenylethylbenzene, isopropenylpropylbenzene, isopropenylbutylbenzene, isopropenylpentylbenzene, isopropenylhexylbenzene, and isopropenyloctylbenzene. Among these, styrene is preferred from the viewpoint of the balance between strength and moldability. These aromatic vinyl monomers may be used alone or in combination of two or more. That is, the homopolymer (A1) of the styrene-based monomer (a1) referred to here means a polymer of only the styrene-based monomer (a1), and may be a copolymer of two or more types of the styrene-based monomer (a1).

[0014] <Weight average molecular weight (Mw)> From the viewpoint of strength and moldability, the homopolymer (A1) of the styrene-based monomer (a1) according to this embodiment preferably has a weight-average molecular weight (Mw) of 50,000 to 700,000, more preferably 150,000 to 400,000. Specifically, for example, Mw is 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, or 700,000, and may be within a range between any two of the values ​​exemplified here. If Mw is too small, the strength of the molded article will be insufficient, while if Mw is too large, moldability will be reduced. The weight-average molecular weight (Mw) of the homopolymer (A1) of the styrene-based monomer (a1) can be controlled by the reaction temperature and residence time in the polymerization step, the type and amount of polymerization initiator, the type and amount of chain transfer agent, the type and amount of solvent used during polymerization, and the like.

[0015] The weight average molecular weight (Mw) can be measured, for example, by using gel permeation chromatography (GPC) under the following conditions. GPC model: Showa Denko Shodex GPC-101 Column: Polymer Laboratories PLgel 10 μm MIXED-B Mobile phase: tetrahydrofuran Sample concentration: 0.2% by mass Temperature: Oven 40℃, injection port 35℃, detector 35℃ Detector: Differential refractometer Molecular weight is calculated as the molecular weight converted into polystyrene by calculating the molecular weight at each elution time from the elution curve of monodisperse polystyrene.

[0016] <Glass transition temperature (Tg)> From the viewpoints of heat resistance and moldability, the homopolymer (A1) of the styrene-based monomer (a1) according to this embodiment preferably has a glass transition temperature (Tg) of 50 to 160° C., more preferably 70 to 120° C. The glass transition temperature (Tg) can be controlled, for example, by adjusting the weight average molecular weight of the monomer (a1) and copolymer (A1) constituting the homopolymer (A1). The glass transition temperature (Tg) can be measured, for example, using an EXTER DSC6200 manufactured by SII Corporation, by raising the temperature from 20° C. at a rate of 10° C. / min.

[0017] <Copolymer (A2) of styrene-based monomer (a1) and monomer (a2) having at least one of an ester group and a carboxyl group> The copolymer (A2) of the styrene-based monomer (a1) and the monomer (a2) having at least one of an ester group or a carboxyl group according to this embodiment is obtained by copolymerizing the styrene-based monomer (a1), which is an aromatic vinyl-based monomer, with a monomer having at least one of an ester group or a carboxyl group copolymerizable therewith. Radical polymerization, anionic polymerization, and cationic polymerization are well-known polymerization methods, and copolymers produced by any of these methods can be used.

[0018] The aromatic vinyl monomer may be the styrene-based monomer (a1) constituting the polymer (A1), preferably styrene. These aromatic vinyl monomers may be used alone or in combination of two or more. When the homopolymer (A1) and the copolymer (A2) are used in combination, the styrene-based monomer (a1) used in the homopolymer (A1) and the styrene-based monomer (a1) used in the copolymer (A2) may be the same or different.

[0019] Examples of the monomer (a2) having at least one of an ester group and a carboxyl group include (meth)acrylic acid and (meth)acrylic acid esters. These monomers (a2) may be used alone or in combination of two or more.

[0020] Examples of (meth)acrylic acids include methacrylic acid and acrylic acid. Among these, methacrylic acid is preferred from the viewpoint of heat resistance. These monomers (a2) may be used alone or in combination of two or more.

[0021] Examples of (meth)acrylic acid esters include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, n-hexyl methacrylate, ethylhexyl methacrylate, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, n-hexyl acrylate, and isobornyl acrylate. Among these, methyl methacrylate is preferred from the viewpoint of the balance between strength and moldability. These monomers (a2) may be used alone or in combination of two or more.

[0022] From the viewpoint of a balance between heat resistance and moldability, the monomer constituting the copolymer (A2) according to this embodiment preferably contains 5 to 97 parts by mass of styrene-based monomer (a1), more preferably 15 to 90 parts by mass, of styrene-based monomer (a1), where the total amount of styrene-based monomer (a1) and monomer (a2) is 100 parts by mass. Specific examples include 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 96, and 97 parts by mass, and may be within a range between any two of the values ​​exemplified here. When styrene-based monomer (a1) is used in combination, the amount of styrene-based monomer (a1) used refers to the total amount of the styrene-based monomer (a1) used in combination.

[0023] From the viewpoint of a balance between heat resistance and moldability, the monomer constituting the copolymer (A2) according to this embodiment preferably contains 3 to 95 parts by mass, more preferably 10 to 85 parts by mass, of the monomer (a2) when the total amount of the styrene-based monomer (a1) and the monomer (a2) is taken as 100 parts by mass. Specific examples include 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, and 95 parts by mass, and may be within a range between any two of the numerical values ​​exemplified here. When the monomer (a2) is used in combination, the amount of the monomer (a2) used refers to the total amount of the monomer (a2) used in combination.

[0024] <Weight average molecular weight (Mw)> The copolymer (A2) of the styrene-based monomer (a1) and the monomer (a2) having at least one of an ester group and a carboxyl group according to this embodiment preferably has a weight-average molecular weight (Mw) of 50,000 to 700,000, more preferably 60,000 to 400,000, from the viewpoint of the balance between strength and moldability. Specifically, the Mw may be, for example, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, or 700,000, and may be within a range between any two of the values ​​exemplified here. If the Mw is too small, the strength of the molded article will be insufficient, while if the Mw is too large, moldability will be reduced. The weight-average molecular weight of the copolymer (A2) can be controlled by the reaction temperature and residence time of the polymerization step, the type and amount of polymerization initiator, the type and amount of chain transfer agent, the type and amount of solvent used during polymerization, and the like. The weight average molecular weight (Mw) can be measured, for example, in the same manner as in the homopolymer (A1) of the styrene-based monomer (a1).

[0025] <Glass transition temperature (Tg)> The copolymer (A2) of the styrene-based monomer (a1) and the monomer (a2) having at least one of an ester group and a carboxyl group according to this embodiment preferably has a glass transition temperature (Tg) of 50 to 160° C., more preferably 70 to 125° C., from the viewpoint of the balance between heat resistance and moldability. The glass transition temperature (Tg) can be controlled, for example, by adjusting the types and contents of the monomers (a1) and (a2) constituting the copolymer (A2) and the weight-average molecular weight of the copolymer (A2). The glass transition temperature (Tg) can be measured, for example, in the same manner as in the homopolymer (A1) of the styrene-based monomer (a1).

[0026] <Rubber-containing styrene resin (A3)> The rubber-containing styrene-based resin (A3) according to this embodiment is a styrene-based resin obtained by graft polymerizing a rubbery polymer onto an aromatic vinyl-based polymer and dispersing the graft polymer particles in a styrene-based resin phase that serves as a matrix. The aromatic vinyl-based polymer is obtained by polymerizing a styrene-based monomer (a1), which is an aromatic vinyl-based monomer. Radical polymerization, anionic polymerization, and cationic polymerization are well-known polymerization methods, and resins produced by any of these methods can be used. Examples of aromatic vinyl-based monomers that provide the aromatic vinyl-based polymer include the styrene-based monomer (a1) that constitutes the polymer (A1) described above, and styrene is preferred from the viewpoint of the balance between strength and moldability. These aromatic vinyl-based monomers may be used alone or in combination of two or more. In addition, when the rubber-containing styrene-based resin (A3) is used in combination with a homopolymer (A1) and / or a copolymer (A2), the styrene-based monomer (a1) used in the homopolymer (A1), the styrene-based monomer (a1) used in the copolymer (A2), and the styrene-based monomer (a1) used in the rubber-containing styrene-based resin (A3) can each be selected independently.

[0027] Examples of rubbery polymers used in the rubber-containing styrene-based resin (A3) according to this embodiment include polybutadiene, styrene-butadiene random or block copolymers, polyisoprene, polychloroprene, styrene-isoprene random, block or graft copolymers, ethylene-propylene rubber, ethylene-propylene-diene rubber, etc., with polybutadiene and styrene-butadiene random, block or graft copolymers being particularly preferred. These may be partially hydrogenated and may be used alone or in combination of two or more.

[0028] The content of the rubbery polymer in 100 parts by mass of the rubber-containing styrene-based resin (A3) according to this embodiment is preferably 1.0 to 25.0 parts by mass, more preferably 5.0 to 20.0 parts by mass, from the viewpoint of strength and moldability. The content of the rubbery polymer may be within the range of any two of the following values: 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0, 13.0, 14.0, 15.0, 16.0, 17.0, 18.0, 19.0, 20.0, 21.0, 22.0, 23.0, 24.0, and 25.0 parts by mass. When a rubbery polymer is used in combination, the amount of the rubbery polymer used refers to the total amount of the rubbery polymers used in combination.

[0029] The content of the rubbery polymer can be measured, for example, as follows. The sample is dissolved in chloroform, a certain amount of iodine monochloride / carbon tetrachloride solution is added, and the mixture is left in a dark place for approximately 1 hour. After that, 15% by mass potassium iodide solution and 50 ml of pure water are added, and the excess iodine monochloride is titrated with 0.1 N sodium thiosulfate / ethanol aqueous solution, and the amount of iodine monochloride added is calculated.

[0030] The volume average particle size of the rubber-like polymer in the rubber-containing styrene-based resin (A3) is preferably 2.0 to 8.0 μm, particularly preferably 2.3 to 7.0 μm, from the viewpoint of strength and rigidity. The volume median particle size is 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 5.0, 5.10, 5.11, 5.12, 5.13, 5.14, 5.15, 5.16, 5.17, 5.18, 5.19, 5.20, 5.21, 5.22, 5.23, 5.24, 5.25, 5.26, 5.27, 5.28, 5.29, 5.30, 5.31, 5.32, 5.33, 5.34, 5.35, 5.36, 5.37, 5.38, 5.39, 5.40, 5.41, 5.42, 5.43, 5.44, 5.45, 5.46, 5.47, 5.48, 5. 7.0, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, and 8.0. When a rubbery polymer is used in combination, the volume average particle size of the rubbery polymer means the volume average particle size of the entire rubbery polymer used in combination.

[0031] The volume average particle diameter of the rubber-like polymer can be measured, for example, as follows. Dissolve the sample in dimethylformamide and measure it with a laser diffraction particle size distribution analyzer (laser diffraction particle analyzer "LS-230 type" manufactured by Beckman Coulter).

[0032] <Z average molecular weight (Mz)> The rubber-containing styrene resin (A3) according to the present embodiment preferably has a Z average molecular weight (Mz) of 200,000 to 1,500,000, more preferably 300,000 to 1,400,000, from the viewpoint of the balance between strength and moldability. Specifically, for example, it is 200,000, 250,000, 300,000, 400,000, 500,000, 600,000, 700,000, 800,000, 900,000, 1,000,000, 1,100,000, 1,200,000, 1,300,000, 1,400,000, 1,500,000, and it may be within the range between any two of the numerical values exemplified here. If Mz is too small, the strength of the molded product will be insufficient, and if Mz is too large, the moldability will deteriorate. The weight average molecular weight of the rubber-containing styrene resin (A3) can be controlled by the reaction temperature, residence time, type and addition amount of the polymerization initiator, type and addition amount of the chain transfer agent, type and amount of the solvent used during polymerization, etc. in the polymerization process of the styrene resin serving as the matrix.

[0033] The Z average molecular weight (Mz) of the rubber-containing styrene resin (A3) can be measured, for example, under the following conditions using gel permeation chromatography (GPC). Note that the rubber-containing styrene resin (A3) used in this example is in a form in which rubber-like dispersed particles are dispersed in the matrix phase of the polystyrene resin, and the molecular weight means the molecular weight of the matrix phase. Therefore, the sample used for molecular weight measurement is a polymer obtained by dissolving the rubber-containing styrene resin (A3) in a 50% methyl ethyl ketone / 50% acetone mixed solution, removing the rubber-like dispersed particles with a centrifuge (H-force 2000B manufactured by Kokusan Co., Ltd. (rotor: H)), and reprecipitating it in methanol. GPC model: Shodex GPC-101 manufactured by Showa Denko K.K. Column: PLgel 5μm MIXED-C manufactured by Polymer Laboratories Mobile phase: Tetrahydrofuran Sample concentration: 0.2% by mass Temperature: Oven 40℃, injection port 35℃, detector 35℃ Detector: Differential refractometer Molecular weight is calculated as the molecular weight converted into polystyrene by calculating the molecular weight at each elution time from the elution curve of monodisperse polystyrene.

[0034] <Glass transition temperature (Tg)> From the viewpoint of heat resistance and moldability, the rubber-containing styrene-based resin (A3) according to this embodiment preferably has a glass transition temperature (Tg) of 50 to 160° C., more preferably 70 to 120° C. The glass transition temperature (Tg) can be controlled, for example, by adjusting the type and content of the monomer (a1) constituting the aromatic vinyl polymer of the rubber-containing styrene-based resin (A3), the type and content of the rubbery polymer used in the rubber-containing styrene-based resin (A3), and the weight-average molecular weight of the rubber-containing styrene-based resin (A3). The glass transition temperature (Tg) can be measured, for example, in the same manner as in the homopolymer (A1) of the styrene-based monomer (a1).

[0035] <Styrene-based resins other than (A1) to (A3)> The styrene-based resin (A) according to this embodiment may contain a styrene-based resin (A4) other than the homopolymer (A1), copolymer (A2), and rubber-containing styrene-based resin (A3) described above, as long as the effects of the present invention are not impaired. Examples of such styrene-based resin (A4) include styrene-maleic anhydride copolymer, styrene-N-phenylmaleimide copolymer, and styrene-acrylonitrile copolymer. Furthermore, the content of the styrene-based resin (A4) per 100 parts by mass of the styrene-based resin (A) according to this embodiment is preferably less than 10 parts by mass. More preferably, the styrene-based resin (A) according to this embodiment contains substantially only one or more selected from the group consisting of the homopolymer (A1), copolymer (A2), and rubber-containing styrene-based resin (A3).

[0036] Examples of polymerization methods for styrene-based resins include known styrene polymerization methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. From the viewpoints 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.

[0037] When polymerizing the styrene resin, a polymerization initiator and a chain transfer agent can be used as necessary. As the polymerization initiator, a radical polymerization initiator is preferred, and examples of the known and commonly used initiators include 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-butyl peroxyacetate and t-amyl peroxyisononanoate, t-butylcumyl peroxide, di-t-butyl peroxide, dicumyl peroxide, and di-t-hexyl peroxide. Examples of suitable peroxides include dialkyl peroxides such as t-butyl peroxyacetate, t-butyl peroxybenzoate, and t-butylperoxyisopropyl monocarbonate; peroxyesters such as t-butylperoxyisopropyl carbonate and polyether tetrakis(t-butylperoxycarbonate); and peroxycarbonates such as N,N'-azobis(cyclohexane-1-carbonitrile), N,N'-azobis(2-methylbutyronitrile), N,N'-azobis(2,4-dimethylvaleronitrile), and N,N'-azobis[2-(hydroxymethyl)propionitrile]. These may be used alone or in combination. Examples of suitable chain transfer agents include aliphatic mercaptans, aromatic mercaptans, pentaphenylethane, α-methylstyrene dimer, and terpinolene.

[0038] <Liquid Crystal Polymer (B)> The liquid crystal polymer (B) according to this embodiment is a thermoplastic resin that exhibits liquid crystallinity when melted and can form an anisotropic melt phase. It is classified into fully aromatic and semi-aromatic types based on its molecular structure. Examples include liquid crystal polyesters that are composed of monomer units selected from aromatic oxycarbonyl monomer units, aromatic dioxy monomer units, aromatic and / or aliphatic dicarbonyl monomer units, and alkylenedioxy monomer units, and that form an anisotropic melt phase; and liquid crystal polyesteramides that are composed of the above monomer units and monomer units selected from aromatic iminocarbonyl monomer units, aromatic diimino monomer units, and aromatic iminoxy monomer units, and that form an anisotropic melt phase. The liquid crystal polymer (B) according to this embodiment may be used alone or in combination of two or more.

[0039] <Monomers that provide aromatic oxycarbonyl monomer units> Examples of monomers that provide aromatic oxycarbonyl monomer units include aromatic hydroxycarboxylic acids such as 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 2-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 5-hydroxy-2-naphthoic acid, 3-hydroxy-2-naphthoic acid, 4'-hydroxyphenyl-4-benzoic acid, 3'-hydroxyphenyl-4-benzoic acid, and 4'-hydroxyphenyl-3-benzoic acid, as well as alkyl-, alkoxy-, or halogen-substituted versions of these compounds, and ester-forming derivatives thereof such as acylation products, ester derivatives, and acid halides. These monomers that provide aromatic oxycarbonyl monomer units may be used alone or in combination of two or more.

[0040] <Monomers that provide aromatic dioxy monomer units> Examples of monomers that provide aromatic dioxymer units include aromatic diols such as hydroquinone, resorcinol, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 4,4'-dihydroxybiphenyl, 3,3'-dihydroxybiphenyl, 3,4'-dihydroxybiphenyl, and 4,4'-dihydroxybiphenyl ether, as well as ester-forming derivatives thereof such as alkyl, alkoxy, or halogen-substituted products, and acylated products thereof. These monomers that provide aromatic dioxymer units may be used alone or in combination of two or more.

[0041] <Monomers that provide aromatic dicarbonyl monomer units> Examples of monomers that provide aromatic dicarbonyl monomer units include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, and 4,4'-dicarboxybiphenyl, as well as alkyl-, alkoxy-, or halogen-substituted derivatives thereof, and ester-forming derivatives thereof such as ester derivatives and acid halides. These monomers that provide aromatic dicarbonyl monomer units may be used alone or in combination of two or more.

[0042] <Melting point of liquid crystal polymer> The melting point of the liquid crystal polymer (B) according to this embodiment is preferably less than 240° C., more preferably less than 220° C., from the viewpoint of moldability. Specifically, it is, for example, less than 240, 235, 230, or 220° C. The melting point of the liquid crystal polymer (B) can be controlled, for example, by adjusting the type and content of the monomer units constituting the liquid crystal polymer. Alternatively, commercially available liquid crystal polymers having such a melting point can be used. An example of a commercially available product is the liquid crystal polymer AL-8100 (melting point 220°C) manufactured by Ueno Pharmaceutical Co., Ltd. In the present embodiment, the melting point of the liquid crystal polymer (B) is a value measured by a differential scanning calorimeter (DSC) at a temperature rise rate of 20° C. / min.

[0043] <Method of manufacturing liquid crystal polymer> The method for producing the liquid crystal polymer (B) according to this embodiment is not particularly limited, and the polymer can be obtained, for example, by appropriately combining the above-mentioned monomers and forming ester bonds, amide bonds, etc. using a known polycondensation method, such as a melt acidolysis method or a slurry polymerization method.

[0044] <Other resin components (C)> The styrene-based resin composition of this embodiment may contain another resin component (C) other than the styrene-based resin (A) and the liquid-crystalline polymer (B) within a range that does not impair the effects of the present invention. Furthermore, the content of the other resin component (C) per 100 parts by mass of the styrene-based resin composition of this embodiment is preferably less than 10 parts by mass, more preferably less than 5 parts by mass. More preferably, the styrene-based resin composition of this embodiment contains substantially only the styrene-based resin (A) and the liquid-crystalline polymer (B).

[0045] Furthermore, various additives, for example, known additives such as dyes and pigments, coloring inhibitors, lubricants, antioxidants, antiaging agents, light stabilizers, antistatic agents, fillers, compatibilizers, and modifiers such as colorants such as titanium oxide and carbon black, can be added to the styrene-based resin composition of this embodiment within the range in which the effects of the present invention can be obtained. Preferably, the styrene-based resin composition of this embodiment does not contain a compatibilizer. The method of adding these is not particularly limited, and they can be added by known methods, for example, before the start of polymerization of the styrene-based resin (A) used, to the reaction liquid during polymerization, or after the completion of polymerization, when blending the liquid crystal polymer (B), and even in an extruder or molding machine.

[0046] <Mixing method> Known mixing techniques can be applied to the method for mixing the styrene-based resin composition according to this embodiment. For example, a mixture premixed in advance using a mixing device such as a mixer-type mixer, a V-type blender, or a tumbler-type mixer can be melt-kneaded to obtain a homogeneous resin composition. There are no particular limitations on the melt-kneader. Suitable melt-kneaders include a Banbury mixer, a kneader, a roll, a single-screw extruder, a special single-screw extruder, and a twin-screw extruder. Furthermore, there is a method in which additives such as a flame retardant are separately added midway through the melt-kneading device such as an extruder.

[0047] When a twin-screw extruder is used, the temperature during melt kneading is 200 to 260°C, preferably 220 to 255°C, in terms of the cylinder temperature of the kneading section. If the cylinder temperature is less than 200°C, the resin will not melt sufficiently, making it impossible to obtain a uniform dispersion. On the other hand, if the temperature exceeds 260°C, the styrene resin will decompose, causing a decrease in physical properties, which is undesirable.

[0048] In this embodiment, the cylinder temperature of the kneading section refers to the set temperature of the section in which the kneading section cylinder (mixing element) is located and which has the highest temperature among the sections in which the material to be melt-kneaded is kneaded, in a twin-screw extruder in which the space in which the cylinder is located is divided into multiple sections from the raw material inlet section to the outlet section and the temperature of each section can be controlled.

[0049] <Deflection temperature under load of styrene-based resin composition> From the viewpoint of practical heat resistance, the deflection temperature under load of the styrene-based resin composition of the present embodiment is preferably 90° C. or higher, and more preferably 100° C. or higher. Specifically, for example, 90, 95, 100, 105, 110, 115, 120, or 130° C. or higher is preferred. The deflection temperature under load can be controlled by adjusting the types and contents of the styrene resin (A) and the liquid crystal polymer (B) that constitute the styrene resin composition. The deflection temperature under load of the styrene-based resin composition of the present embodiment can be determined in accordance with JIS K 7191 using the flatwise method under a stress of 1.8 MPa.

[0050] <Molded products> Examples of molding methods for obtaining molded articles from the styrene-based resin composition of this embodiment include extrusion molding, compression molding, injection molding, blow molding, injection blow molding, and calender molding. [Example]

[0051] The following examples and comparative examples will be used to explain specific embodiments of the present invention in more detail, but the present invention is not limited to these examples.

[0052] <Production Example of Styrene-Based Resin Composition> [Materials used] [Styrene-based resin (A)] <Homopolymer (A1) of styrene-based monomer (a1)> (A1-1) GPPS (styrene polymer, weight average molecular weight (Mw) 300,000, glass transition temperature (Tg) 100°C) <Rubber-containing styrene resin (A3)> (A3-1) HIPS (polystyrene resin modified with polybutadiene rubber, Z-average molecular weight (Mz) 400,000, glass transition temperature (Tg) 93°C, rubber polymer content 6.0 parts by mass, volume average particle diameter 2.7 μm) <Copolymer (A2) of styrene-based monomer (a1) and monomer (a2) having at least one of an ester group and a carboxyl group> (A2-1) Styrene-methacrylic acid copolymer (weight average molecular weight (Mw) 160,000, glass transition temperature (Tg) 125°C, methacrylic acid monomer 10 parts by mass) (A2-2) Styrene-methyl methacrylate copolymer (weight average molecular weight (Mw) 70,000, glass transition temperature (Tg) 93°C, methyl methacrylate monomer 75 parts by mass) [Liquid Crystal Polymer (B)] (B-1) AL-8100 (melting point 220°C) manufactured by Ueno Pharmaceutical Co., Ltd. [Non-styrene resin] Non-styrene resin: Unitika polyethylene terephthalate SA-863JP (melting point 235°C)

[0053] The styrene-based resin (A), liquid crystal polymer (B), and non-styrene-based resin were compounded in the amounts shown in the table, premixed in a Henschel mixer (FM20B, manufactured by Mitsui Miike Chemical Co., Ltd.), and fed into a twin-screw extruder (TEM26SS, manufactured by Toshiba Machine Co., Ltd.) to form strands at a cylinder temperature of 250°C and a feed rate of 35 kg / h. The strands were then cooled with water and fed into a pelletizer to be pelletized. The pellets obtained as described above were dried by heating at 80°C for 3 hours, and then molded into A-type test pieces (dumbbells) according to JIS K 7139 using an injection molding machine ("J100E-P" manufactured by The Japan Steel Works, Ltd.) at a cylinder temperature of 240°C and a mold temperature of 45°C.

[0054] <Melt Mass Flow Rate (MFR)> The melt mass flow rate of the styrene-based resin composition according to this embodiment was measured under conditions of 200° C. and a load of 49 N in accordance with JIS K7210.

[0055] <Deflection temperature under load> The deflection temperature under load of the styrene-based resin composition according to this embodiment was measured in accordance with JIS K 7191 using the flatwise method under a stress of 1.8 MPa.

[0056] <Charpy impact strength> The impact resistance of the resin composition in this embodiment was evaluated by the Charpy impact value. The Charpy impact strength was measured according to the conditions of JIS K 7111-1 using a test piece cut from the center of a dumbbell and notched (type A, r = 0.25 mm) by cutting.

[0057] [Table 1]

[0058] [Table 2]

[0059] The results in Table 1 show that the styrene resin compositions according to the examples have excellent heat resistance and impact resistance. On the other hand, the results in Table 2 show that the copolymers according to the comparative examples are inferior in one or more aspects of heat resistance and impact resistance. In addition, some of the copolymers had extremely low fluidity, making it impossible to prepare test specimens. [Industrial Applicability]

[0060] The styrene-based resin composition according to the present invention, which contains a styrene-based resin and a liquid crystal polymer, has excellent heat resistance and impact resistance. The styrene-based resin composition according to the present invention can be suitably used as a molded article or a film, and has industrial applicability.

Claims

1. When the total of the styrene-based resin A and the liquid crystal polymer B is 100 parts by mass, the composition contains 20 to 70 parts by mass of the styrene-based resin A and 30 to 80 parts by mass of the liquid crystal polymer B, the styrene-based resin A is a copolymer A2 of a styrene-based monomer a1 and a monomer a2 having an ester group, the monomer a2 having an ester group is methyl methacrylate, The monomers constituting the copolymer A2 contain 45 to 95 parts by mass of the monomer a2 having an ester group, when the total amount of the styrene-based monomer a1 and the monomer a2 having an ester group is 100 parts by mass, A styrene-based resin composition, wherein the styrene-based resin A has an atactic structure.

2. The styrene-based resin composition according to claim 1, wherein the Charpy impact strength measured under the conditions of JIS K 7111-1 using a test piece cut from the center of a dumbbell piece and machined with a notch (Type A, r = 0.25 mm) is 8 to 20 kJ / m 2 .

3. A styrene-based resin composition according to claim 1 or claim 2, having a melt mass flow rate of 0.2 to 1.4 g / 10 min measured at 200°C under a load of 49 N according to JIS K7210.

4. 4. The styrene-based resin composition according to claim 1, which has a deflection temperature under load of 100° C. or higher when measured in accordance with JIS K 7191 using a flatwise method under a stress of 1.8 MPa.

5. The styrene-based resin composition according to any one of claims 1 to 4, wherein the liquid crystal polymer B has a melting point of less than 240°C.

6. A molded article made from the styrene-based resin composition according to any one of claims 1 to 5.

7. A film comprising the styrene-based resin composition according to any one of claims 1 to 5.

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