JP2012207074A - Transparency styrene-based thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition in which the transparency, color tone stability, impact resistance, and flowability are excellent.SOLUTION: The transparency styrene-based thermoplastic resin composition is characterized as follows. A resin composition includes: 10-100 pts.wt. of a graft copolymer (A) which comprises graf-copolymerizing 50-97 wt.% of a monomer mixture (a) containing at least an aromatic vinyl monomer (a1) and an unsaturated carboxylic acid alkyl ester based monomer (a2); and 0-90 pts.wt. of a vinyl based polymer (B) which comprises polymerizing at least an aromatic vinyl monomer (b1) and an unsaturated carboxylic acid alkyl ester based monomer (b2), under the presence of 3-50 wt.% of a styrene-butadiene rubber quality polymer (r) of a weight-average particle size of 0.30-0.70 μm in which the particle diameter of at least 1 μm is 2-10 wt.% of the entire particles, and the particle diameter of 0.1 μm is at most 20 wt.% of the entire particles, wherein the ratio of the rubber quality polymer (r) to the weight of the resin composition is 3-25 wt.%.

Description

  The present invention relates to a styrenic thermoplastic resin composition having excellent balance of transparency, color stability, impact resistance and fluidity.

  Styrenic thermoplastic resin compositions containing rubber are widely used in application fields such as automotive materials, home appliances, and general goods because of their excellent mechanical strength balance such as impact resistance and rigidity, and excellent moldability. . However, since the styrenic thermoplastic resin composition containing rubber is generally opaque, it cannot be applied to the product field where transparency is required.

  As a conventional technique for providing a transparent styrene-based thermoplastic resin composition having excellent balance of transparency, color stability, impact resistance and fluidity of a resin, Patent Document 1 discloses a styrene-butadiene block rubber material. When copolymerizing styrene and methyl methacrylate in the presence of a polymer, the styrene-butadiene rubbery polymer is characterized in that the proportion of 1,2-vinyl bonds among unsaturated bonds based on butadiene is 14-25%. Using a certain styrene-butadiene rubber polymer, the graft copolymer has a toluene insoluble content of 4 to 22% by weight, a toluene swelling index of 11 to 19, and a toluene insoluble content of swelling / swelling index of 0.15. It has been proposed that a rubber-containing styrene resin composition having excellent transparency and impact resistance can be provided by setting the content to ˜1.10% by weight, but the impact resistance is sufficient. Not say.

  Patent Document 2 discloses a weight average particle of a rubbery polymer as a characteristic of a styrene-butadiene rubbery polymer used when copolymerizing styrene and methyl methacrylate having a refractive index close to that of a styrene-butadiene block rubbery polymer. A styrene-butadiene rubbery polymer having a diameter of 0.1 to 2 μm, a 1,2-vinyl bond ratio of 1.0 to 13.8%, and a particle size distribution index of 2.0 to 5.0 is used. Thus, it has been proposed that a rubber-containing styrenic resin composition having excellent transparency and impact resistance can be provided, but this also has insufficient impact resistance.

  In Patent Document 3, acrylonitrile is copolymerized with a styrene-butadiene block rubbery polymer in addition to styrene and methyl methacrylate for the purpose of imparting chemical resistance. A characteristic of the styrene-butadiene rubber polymer used is a copolymer having a polystyrene block of 5 to 35% by weight, and the rubber polymer particle dispersed phase has a rubbery polymer having an occlusion structure containing four or more particles. The number of coalesced particles is 2 to 20% with respect to the number of all rubbery polymer particles, and the number of rubbery polymer particles having no occlusion structure is 20 to 20 with respect to the number of all rubbery polymer particles. The copolymer has a feature of 80%, and a copolymer having a weight average molecular weight of 3000 to 50000 in a ratio of 15 to 50% by weight is used for the copolymerization continuous phase, so that chemical resistance, impact resistance, transparency, etc. Resins with well-balanced physical properties have been proposed. However, since it is manufactured by solution polymerization, a multi-stage polymerization tank is required for the purpose of improving the dispersibility of the rubbery polymer, which increases production costs and controls polymerization at high temperatures. It becomes difficult to control the particle diameter and the graft ratio, resulting in poor impact resistance and surface gloss.

  In Patent Document 4, when copolymerizing styrene and methyl methacrylate with a styrene-butadiene block rubbery polymer, as a feature of the styrene-butadiene rubbery polymer used, the rubbery polymer polymer particle diameter is 0.78 μm or more. It has been proposed that a resin composition having excellent practical transparency and impact resistance can be provided by solution polymerization using a styrene-butadiene rubbery polymer having 0 to 25% by mass of particles, Inferior to impact and surface gloss.

Japanese Patent Laid-Open No. 4-180907 JP-A-8-239532 JP 2002-37821 A JP 2004-339357 A

  Accordingly, an object of the present invention is to provide a transparent styrenic thermoplastic resin composition that eliminates the disadvantages of the prior art and is excellent in transparency, color stability, impact resistance, and fluidity.

  As a result of intensive studies to achieve the above object, the present inventor has optimized the particle size distribution of the styrene-butadiene rubbery polymer so that transparency, color stability, impact resistance and fluidity can be obtained. The present inventors have found that an excellent transparent styrene-based thermoplastic resin composition can be obtained, and have reached the present invention.

  That is, the present invention is a weight average having a particle size distribution such that the particle size of 1 μm or more is 2 to 10% by weight of the whole particle and the particle size of 0.1 μm or less is 20% by weight or less of the whole particle. At least aromatic vinyl monomer (a1) and unsaturated carboxylic acid alkyl ester monomer in the presence of 3 to 50% by weight of styrene-butadiene rubber polymer (r) having a particle size of 0.30 to 0.70 μm Monomer mixture containing (a2) (a) 10 to 100 parts by weight of graft copolymer (A) obtained by graft copolymerization of 50 to 97% by weight, and at least aromatic vinyl monomer (b1) And a vinyl polymer (B) obtained by polymerizing an unsaturated carboxylic acid alkyl ester monomer (b2), in a resin composition containing 0 to 90 parts by weight, rubbery polymerization relative to the weight of the resin composition Ratio of (r) is characterized in that 3 to 25% by weight, a transparent styrene-based thermoplastic resin composition.

  According to the present invention, it is possible to obtain a transparent styrenic thermoplastic resin composition having excellent balance of transparency, color tone stability, impact resistance and fluidity.

[Graft Copolymer (A)]
The styrene-butadiene rubbery polymer (r), which is a rubber component of the graft copolymer (A), is characterized by having a weight average particle diameter of 0.30 to 0.70 μm. This is not preferable when the weight average particle diameter is less than 0.30 μm, because the impact resistance is lowered, and when the weight average particle diameter exceeds 0.70 μm, in addition to the decrease in impact resistance, the surface gloss It is because it is not preferable because the properties are lowered.

  The styrene-butadiene rubber polymer (r) is a rubber material in which the rubber polymer having a particle size of 1 μm or more is 2 to 10% by weight of the whole particle and the particle size is 0.1 μm or less. It is characterized in that the polymer is 20% by weight or less of the whole particle. If the rubbery polymer having a particle size of 1 μm or more is less than 2% by weight of the whole particle, the impact resistance improvement effect by the rubbery polymer having a large particle size in the resin composition is reduced, If it exceeds 10% by weight, the number of rubber particles relative to the weight of the total resin composition decreases, impact resistance decreases, and surface gloss decreases due to an increase in the proportion of large particle size rubber. In addition, when the rubbery polymer having a particle size of 0.1 μm or less is 20% by weight or more of the whole particle, the impact absorbing ability to the rubbery polymer is reduced, This is because the impact property is lowered.

  Styrene monomers constituting the styrene-butadiene rubber polymer (r) include styrene, α-methyl styrene, p-methyl styrene, m-methyl styrene, o-methyl styrene, vinyl toluene, t-butyl styrene. Styrene is preferable. These can be used alone or in combination of two or more.

  Examples of the diene monomer constituting the styrene-butadiene rubbery polymer (r) include 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 1 1,3-pentadiene, 1,3-hexadiene, etc. are preferable, and 1,3-butadiene is preferable. These can be used alone or in combination of two or more.

  The constitution of the styrene monomer and diene monomer constituting the styrene-butadiene rubber polymer (r) is not particularly limited, but the styrene monomer 5 to 30% by weight and the diene monomer It is preferably composed of 95 to 70% by weight. When the styrenic monomer is less than 5% by weight, the hue and transparency change due to the thermal history may be increased. On the other hand, when the styrenic monomer exceeds 30% by weight, the styrenic component The increase in the viscosity increases the glass transition temperature of the rubbery polymer, which may reduce the impact resistance. The styrene-butadiene rubber polymer (r) is preferably a random copolymer of a styrene monomer and a diene monomer.

  As described above, the styrene-butadiene rubbery polymer (r) has a characteristic in the particle size distribution. As a method for adjusting the particle size distribution, for example, a method of blending two or more rubber components having different particle sizes is used. Can be adjusted easily. The graft copolymer (A) contains at least an aromatic vinyl monomer (a1) and an unsaturated carboxylic acid alkyl ester monomer in the presence of 3 to 50% by weight of the styrene-butadiene rubber polymer (r). A graft copolymer obtained by graft copolymerizing 50 to 97% by weight of the monomer mixture (a) containing the body (a2).

  When the styrene-butadiene rubber polymer (r) is less than 3% by weight, the rubber component in the transparent styrenic thermoplastic resin composition is not sufficient and impact resistance is lowered, which is undesirable. When the butadiene rubber polymer (r) exceeds 50% by weight, the dispersibility of the styrene-butadiene rubber polymer (r) is lowered, which is not preferable because it causes a reduction in impact resistance and fish eyes.

  The monomer mixture (a) contains at least an aromatic vinyl monomer (a1) and an unsaturated carboxylic acid alkyl ester monomer (a2) from the viewpoint of the refractive index of the graft component described later. However, the vinyl cyanide monomer (a3) and other monomers (a4) copolymerizable with these monomers may be contained to such an extent that the transparency is not impaired.

  Examples of the aromatic vinyl monomer (a1) include styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene, o-methylstyrene, vinyltoluene, and t-butylstyrene. preferable. These can be used alone or in combination of two or more.

  Examples of the unsaturated carboxylic acid alkyl ester monomer (a2) include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, (meth ) T-butyl acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, chloromethyl (meth) acrylate, and the like, and methyl (meth) acrylate is preferred. These can be used alone or in combination of two or more.

  Examples of the vinyl cyanide monomer (a3) include acrylonitrile, methacrylo, tolyl, ethacrylonitrile and the like, and acrylonitrile is preferred. These can be used alone or in combination of two or more.

  As the other monomer (a4), for example, unsaturated fatty acid, acrylamide monomer, maleimide monomer and the like can be used. These can be used alone or in combination of two or more.

  Examples of the unsaturated fatty acid include itaconic acid, maleic acid, fumaric acid, butenoic acid, acrylic acid, and methacrylic acid.

  Examples of the acrylamide monomer include acrylamide, methacrylamide, N-methylacrylamide and the like.

  Examples of maleimide monomers include N-methylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-hexylmaleimide, N-octylmaleimide, N-dodecylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide and the like. It is done.

  In addition, the graft ratio of the graft polymer (A) is preferably 30% or more. When the graft ratio is 30% or more, the dispersibility of the rubbery polymer is improved and the impact resistance is improved. However, when the graft ratio is less than 30%, the compatibility of the rubber in the resin composition is deteriorated. In some cases, impact resistance may be reduced.

  In order to obtain excellent transparency, it is preferable that the difference in refractive index between the styrene-butadiene rubber polymer (r) and the graft component in the graft copolymer (A) is within 0.03. Furthermore, it is preferable to set the refractive index of the styrene-butadiene rubber polymer (r) to 1.52 to 1.54 and the refractive index of the graft component to 1.49 to 1.57. The refractive index referred to in the present specification is a value measured by an Abbe refractometer.

  The preferable refractive index of the styrene-butadiene rubbery polymer (r) can be set by the ratio of the styrene monomer to the diene monomer. Specifically, as described above, the styrene monomer 5 By adjusting the content to -30% by weight and the diene monomer 95-70% by weight, it can be adjusted to a preferable range.

  The refractive index of the graft component refers to the refractive index of the graft component of the graft copolymer (A) contained in the supernatant liquid extracted from the graft copolymer (A) with acetone and then separated from the solid content by centrifugation or the like. This is adjusted by the monomer composition ratio of the monomer mixture (a). Specifically, aromatic vinyl monomer (a1) 20 to 70% by weight, unsaturated carboxylic acid alkyl ester monomer (a2) 30 to 80% by weight, vinyl cyanide monomer (a3) By using a monomer mixture (a) containing 0 to 10% by weight and 0 to 10% by weight of another monomer (a4) copolymerizable therewith, it can be adjusted to a preferred range.

  Although there is no restriction | limiting in the polymerization method of a graft copolymer (A), In the case of emulsion polymerization, since the particle diameter adjustment of a styrene-butadiene rubber-like polymer (r) is easy, it is preferable.

  As the initiator used for the graft polymerization, a peroxide or an azo compound and water-soluble potassium persulfate are used. Specific examples of the peroxide include benzoyl peroxide, cumene hydroperoxide, dicumyl peroxide, diisopropylbenzene hydroperoxide, t-butyl hydroperoxide, t-butyl peroxyacetate, t-butyl peroxybenzoate, t-butyl isopropyl carbonate, di-t-butyl peroxide, t-butyl peroctate, 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane, 1,1-bis (T-butylperoxy) cyclohexane, t-butylperoxy-2-ethylhexanoate and the like.

  Specific examples of the azo compound include azobisisobutyronitrile, azobis (2,4-dimethylvaleronitrile, 2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile, 2-cyano-2-propylazo. Formamide, 1,1′-azobiscyclohexane-1-carbonitrile, azobis (4-methoxy-2,4-dimethylvaleronitrile), dimethyl 2,2′-azobisisobutyrate, 1-t-butylazo-2 -Cyanobutane, 2-t-butylazo-2-cyano-4-methoxy-4-methylpentane, etc. When these initiators are used, they are used alone or in combination of two or more. However, for emulsion polymerization, potassium persulfate, cumene hydroperoxide, etc. are preferably used, and the initiator is a redox system. It can be also used.

  Chain transfer agents such as mercaptans and terpenes may be used for the purpose of adjusting the degree of polymerization and graft ratio of the graft copolymer (A). Specific examples thereof include n-octyl mercaptan and t-dodecyl mercaptan. N-dodecyl mercaptan, n-tetradecyl mercaptan, n-octadecyl mercaptan, terpinolene and the like. When these chain transfer agents are used, they are used alone or in combination of two or more. Of these, n-octyl mercaptan and t-dodecyl mercaptan are preferably used.

  There is no particular limitation on the emulsifier used in the case of emulsion polymerization, and various surfactants can be used, but anionic surfactants such as carboxylate type, sulfate ester type, and sulfonate type are preferably used. The Specific examples of such emulsifiers include caprylate, caprate, laurate, misty phosphate, palmitate, stearate, oleate, linoleate, linolenate, rosinate, Behenate, castor oil sulfate, lauryl alcohol sulfate, dodecylbenzene sulfonate, alkyl naphthalene sulfonate, alkyl diphenyl ether disulfonate, naphthalene sulfonate condensate, dialkyl sulfosuccinate, polyoxyethylene lauryl Examples thereof include sulfates, polyoxyethylene alkyl ether sulfates, and polyoxyethylene alkyl phenyl ether sulfates. Examples of the salt herein include alkali metal salts, ammonium salts, sodium salts, lithium salts, and the like. These emulsifiers are used alone or in combination of two or more.

  From the graft copolymer latex produced by emulsion polymerization, a coagulant is then added to recover the graft copolymer. Acid or water-soluble salt is used as the coagulant. Examples include sulfuric acid, hydrochloric acid, phosphoric acid, acetic acid, calcium chloride, magnesium chloride, barium chloride, aluminum chloride, magnesium sulfate, aluminum sulfate, aluminum ammonium sulfate, and aluminum sulfate. Examples include potassium and sodium aluminum sulfate. These coagulants are used alone or in combination of two or more. In order to obtain a highly transparent resin, it is preferable not to leave an emulsifier in the resin. It is preferable to use an alkali fatty acid salt as the emulsifier and to perform acid coagulation.

  The monomer charging method is not particularly limited, and initial batch charging, part or all of the monomer may be continuously charged to control the distribution of the copolymer composition, Parts or all may be divided and charged.

[Vinyl polymer (B)]
The vinyl polymer (B) is a vinyl polymer obtained by polymerizing at least the aromatic vinyl monomer (b1) and the unsaturated carboxylic acid alkyl ester monomer (b2). The vinyl cyanide monomer (b3) and other monomers (b4) copolymerizable with these monomers may be contained to the extent that they are not impaired.

  Examples of the aromatic vinyl monomer (b1) include styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene, o-methylstyrene, vinyltoluene, and t-butylstyrene. preferable. These can be used alone or in combination of two or more.

  Examples of the unsaturated carboxylic acid alkyl ester monomer (b2) include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, (meth ) T-butyl acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, chloromethyl (meth) acrylate, and the like, and methyl (meth) acrylate is preferred. These can be used alone or in combination of two or more.

  Examples of the vinyl cyanide monomer (b3) include acrylonitrile, methacrylo, tolyl, and ethacrylonitrile, with acrylonitrile being preferred. These can be used alone or in combination of two or more.

  As the other monomer (b4), an unsaturated fatty acid, an acrylamide monomer, a maleimide monomer, or the like can be used. These can be used alone or in combination of two or more.

  Examples of the unsaturated fatty acid include itaconic acid, maleic acid, fumaric acid, butenoic acid, acrylic acid, and methacrylic acid.

  Examples of the acrylamide monomer include acrylamide, methacrylamide, N-methylacrylamide and the like.

  Examples of maleimide monomers include N-methylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-hexylmaleimide, N-octylmaleimide, N-dodecylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide and the like. It is done.

  In addition, in order to obtain excellent transparency, the difference in refractive index between the styrene-butadiene rubber polymer (r) and the vinyl polymer (B) is preferably within 0.03, The refractive index of the vinyl monomer (B) is preferably set to 1.49 to 1.57. The refractive index of the vinyl polymer (B) can be adjusted by the monomer composition ratio. Specifically, the aromatic vinyl monomer (b1) is 20 to 70% by weight, and the unsaturated carboxylic acid alkyl ester. 30 to 80% by weight of the monomer (b2), 0 to 10% by weight of the vinyl cyanide monomer (b3), and 0 to 10% by weight of the other monomer (b4) copolymerizable therewith By doing so, it can be adjusted to a preferable range.

  The polymerization method of the vinyl monomer (B) is not particularly limited, but a bulk polymerization method and a suspension polymerization method are preferably selected from the viewpoint of transparency and productivity.

  In suspension polymerization, a suitable non-solvent can be used as a dispersion medium for the monomer mixture, but water is preferred because of good heat removal efficiency of polymerization heat and ease of treatment after polymerization.

  The suspension stabilizer used for suspension polymerization is not particularly limited, but inorganic suspension stabilizers such as clay, barium sulfate, magnesium hydroxide, polyvinyl alcohol, carboxymethylcellulose, hydroxyethylcellulose, polyacrylamide, methyl methacrylate / Organic suspension stabilizers such as acrylamide copolymers, etc. Among them, organic suspension stabilizers are preferably used in terms of color stability. These suspension stabilizers are used alone or in combination of two or more.

  As the initiator and chain transfer agent that can be used in suspension polymerization, the initiators and chain transfer agents mentioned in the production of the graft copolymer (A) can be used.

[Transparent Styrenic Thermoplastic Resin Composition]
The styrene thermoplastic resin composition of the present invention can be obtained by mixing the graft copolymer (A) and the vinyl polymer (B). The mixing ratio of the graft copolymer (A) and the vinyl polymer (B) is 10 to 100 parts by weight of the graft copolymer (A) and the vinyl polymer (from the viewpoint of impact resistance and fluidity). B) 0 to 90 parts by weight, preferably 30 to 60 parts by weight of the graft copolymer (A), and 40 to 70 parts by weight of the vinyl polymer (B).

  Further, the graft copolymer (A) is used so that the content of the styrene-butadiene rubber polymer (r) in the transparent styrene thermoplastic resin composition is 3 to 25% by weight, preferably 10 to 18% by weight. And vinyl polymer (B) are mixed. When the content of the styrene-butadiene rubber polymer (r) in the resin composition is less than 3% by weight, the impact resistance is lowered, and the content of the styrene-butadiene rubber polymer (r) is 25% by weight. If it exceeds 50%, a decrease in fluidity is observed, which is not preferable.

  Further, from the viewpoint of the transparency of the resin composition, the difference in refractive index between the acetone-soluble component and the styrene-butadiene rubber polymer (r) is preferably 0.03 or less, more preferably 0.02 or less, and still more preferably 0. The graft copolymer (A) and the vinyl polymer (B) are mixed so as to be 0.01 or less. The acetone-soluble component referred to here is derived from the transparent styrene-based thermoplastic resin composition contained in the supernatant liquid extracted from the transparent styrene-based thermoplastic resin composition with acetone and then separated from the solid content by centrifugation or the like. It is an ingredient. The difference in refractive index between the acetone-soluble component of the resin composition and the styrene-butadiene rubber polymer (r) is, as described above, the styrene-butadiene rubber polymer (r) and the graft component in the graft copolymer (A). By adjusting the difference in refractive index between the styrene-butadiene rubber polymer (r) and the vinyl polymer (B), it can be adjusted to a desired range.

  The method of blending the graft copolymer (A) and the vinyl polymer (B) to obtain the transparent styrene thermoplastic resin composition is not particularly limited, but a preferable method is a method of melt-kneading both components. It is done.

  In the transparent styrene-based thermoplastic resin composition of the present invention, the haze as an index of transparency is preferably 20 or less, more preferably 15 or less, and most preferably 10 or less.

  In addition, the transparent styrene-based thermoplastic resin composition of the present invention includes hindered phenol-based, sulfur-containing organic compound-based, phosphorus-containing organic compound-based antioxidants, phenol-based, acrylate and the like within a range not impairing the effects of the present invention Heat stabilizers such as benzotriazole, UV absorbers such as benzotriazole, benzophenone and salicylate, various stabilizers such as light stabilizers such as organic nickel and hindered amines, metal salts of higher fatty acids, higher fatty acid amides, etc. Lubricants, plasticizers such as phthalates, phosphates, halogen-containing compounds such as polybromodiphenyl ether, tetrabromobisphenol-A, brominated epoxy oligomers, brominated polycarbonate oligomers, phosphorus compounds, antimony trioxide Flame retardants and flame retardants, antistatic agents, carbon black, titanium dioxide , It may be added pigments and dyes, water and silicone oil, a liquid such as liquid paraffin. Furthermore, reinforcing agents and fillers such as glass fibers, glass flakes, glass beads, carbon fibers, and metal fibers can be added. There is no restriction | limiting in particular about the addition method of these additives, A various method can be used.

  Thus, the transparent styrenic thermoplastic resin composition of the present invention has excellent balance of transparency, color stability, impact resistance and fluidity, and balance of mechanical strength such as rigidity, molding processability and cost performance. Therefore, it can be widely used in application fields such as home appliances, communication-related equipment, and general goods.

  EXAMPLES Hereinafter, although an Example is given and this invention is further explained in full detail, this invention is not limited to these Examples.

(1) Weight average particle size and particle size distribution measurement of styrene-butadiene rubber polymer (r) A styrene-butadiene rubber polymer latex is diluted and dispersed in an aqueous medium, and a laser scattering diffraction particle size distribution analyzer “LS” The weight average particle size and particle size distribution were measured with 13 320 ″ (Beckman Coulter, Inc.).

(2) Molecular weight measurement (2-1) Weight average molecular weight of acetone-soluble portion of graft copolymer (A) 80 ml of acetone was added to 1 g of the graft copolymer (A), and it was kept in a 70 ° C. water bath for 3 hours. Reflux and 8000 r. p. After centrifugation at m (10000 G) for 40 minutes, the insoluble matter is filtered. The filtrate was concentrated with an evaporator, and the precipitate (acetone soluble matter) dried under reduced pressure at 60 ° C. for 5 hours was dissolved with terahydrofuran (THF) to 0.1 wt% to prepare a sample. , Water permeation chromatography (GPC) [measurement temperature 40 ° C., column TSK-Supergel HZM-M (front), TSK-Supergel HZM-N (back))] weight average molecular weight with PMMA of known molecular weight as standard And the molecular weight distribution was measured.

(2-2) Measurement of molecular weight of vinyl polymer (B) A sample of vinyl polymer (B) was dissolved in terahydrofuran (THF) to a concentration of 0.1% by weight, and then (2-1 ) The weight average molecular weight was calculated according to the method described.

(3) Graft ratio measurement For a predetermined amount (m: 1 g) of the graft copolymer, the weight (n) of acetone insolubles obtained by the method described in (2-1) is measured, and the graft ratio is calculated from the following formula. Calculated. Here, L is the rubbery polymer content of the graft copolymer (A).
Graft rate (%) = {[(n) − (m) × L] / [(m) × L]} × 100.

(4) Refractive Index Measurement A small amount of 1-bromonaphthalene was added to the sample to be measured, and the refractive index was measured under the following conditions using an Abbe refractometer. In addition, about the refractive index of the acetone soluble part of the graft copolymer (A), the refractive index of the acetone soluble part obtained by the method as described in (2-1) was measured.
Light source: Sodium lamp D-ray measurement temperature: 20 ° C.

(5) Charpy impact strength The resin composition was injection molded, and the obtained molded product was measured for Charpy impact strength according to ISO179.

(6) Melt flow rate (MFR)
The pellets of the resin composition dried for 3 hours in an 80 ° C. hot air dryer were measured by a method based on ISO 1133 (1997, 220 ° C., 98 N).

(7) Transparency (HAZE)
The pellets of the resin composition dried for 3 hours in an 80 ° C. hot air dryer are filled into an injection molding machine (“Promat” (registered trademark) 40/25 manufactured by Sumitomo Heavy Industries, Ltd.) set to a cylinder temperature of 230 ° C. The haze value [%] of the injection molded square plate product (thickness 3 mm) was measured using a direct reading haze meter manufactured by Toyo Seiki Co., Ltd.

(8) Color tone (YI value)
After molding the resin composition at 230 ° C., the obtained molded product was evaluated according to JIS K7105 (1981 established), 6.3 yellowness measurement method.

(Reference Example 1) Graft copolymer (A-1)
The weight of the particle diameter of 1 μm or more is 4.0% by weight of the whole, the weight of the particle diameter of 0.1 μm or less is 6.4% by weight, the weight average particle diameter is 0.43 μm, and the refractive index is 1.534. 40 parts by weight of styrene-butadiene rubbery polymer latex (“J0678” manufactured by JSR Corporation), 130 parts by weight of pure water, 0.4 parts by weight of sodium formaldehyde sulfoxylate, 0 sodium ethylenediaminetetraacetate .1 part by weight, ferrous sulfate 0.01 part by weight and sodium phosphate were charged in a reaction vessel, purged with nitrogen, adjusted to 60 ° C., stirred with styrene 12.2 parts by weight, acrylonitrile 1.2 parts by weight A monomer mixture of 16.6 parts by weight of methyl methacrylate and 0.08 part by weight of t-dodecyl mercaptan was initially added over 1 hour. Next, charging of an initiator mixture of 0.3 parts by weight of cumene hydroperoxide, 1.6 parts by weight of sodium laurate as an emulsifier, and 25 parts by weight of pure water was started to initiate polymerization. The initiator mixture was continuously dropped over 5 hours, and simultaneously, 12.2 parts by weight of styrene, 1.2 parts by weight of acrylonitrile, 16.6 parts by weight of methyl methacrylate and 0.08 parts by weight of t-dodecyl mercaptan. The monomer mixture was continuously added dropwise to the mixture over 4 hours. After the monomer mixture was dropped, only the initiator mixture was continuously dropped for 1 hour to complete the polymerization. The latex after polymerization was coagulated with 1.5% sulfuric acid, then neutralized with sodium hydroxide, washed, centrifuged and dried to obtain a powdered graft copolymer (A-1). The obtained graft copolymer (A-1) had a weight average molecular weight of 120,000, an acetone-soluble component, a graft ratio of 50%, and a refractive index of 1.536.

(Reference Example 2) Graft copolymer (A-2)
Styrene having a particle diameter of 1 μm or more of 17% by weight of the whole, a particle diameter of 0.1 μm or less of 25% by weight of the whole, a weight average particle diameter of 0.48 μm, and a refractive index of 1.535 Reference Example 1 except that butadiene rubber polymer latex (blend adjustment at a ratio of 45% by weight “J0561” manufactured by JSR Corporation, 30% by weight “J0678” manufactured by the company, and 25% by weight “J2108” manufactured by the company) was used. A powdery graft copolymer was obtained by the same method. The obtained graft copolymer (A-2) had a weight-average molecular weight of 120,000, a graft ratio of 43%, and a refractive index of 1.536.

(Reference Example 3) Graft copolymer (A-3)
The weight of the particle diameter of 1 μm or more is 4.0% by weight of the whole, the weight of the particle diameter of 0.1 μm or less is 25% by weight of the whole, the weight average particle diameter is 0.36 μm, and the refractive index is 1.532. Except for using styrene-butadiene rubber polymer latex (blend adjustment at a ratio of 3% by weight “J0561” manufactured by JSR Corporation, 75% by weight “J0678” manufactured by the same company, and 22% by weight “J2108” manufactured by the same company). A powdery graft copolymer was obtained in the same manner as in Example 1. The obtained graft copolymer (A-3) had an acetone-soluble weight average molecular weight of 120,000, a graft ratio of 38%, and a refractive index of 1.536.

(Reference Example 4) Graft copolymer (A-4)
The weight of the particle diameter of 1 μm or more is 17% by weight of the whole, the weight of the particle diameter of 0.1 μm or less is 5.0% by weight of the whole, the weight average particle diameter is 0.60 μm, and the refractive index is 1.536. Except for using styrene-butadiene rubber polymer latex (blend adjustment at a ratio of 42% by weight “J0561” manufactured by JSR Corporation, 54% by weight “J0678” manufactured by the same company, and 2% by weight “J2108” manufactured by the same company). A powdery graft copolymer was obtained in the same manner as in Example 1. The obtained graft copolymer (A-4) had an acetone-soluble weight average molecular weight of 120,000, a graft ratio of 56%, and a refractive index of 1.536.

(Reference Example 5) Graft copolymer (A-5)
A powdery graft copolymer was obtained in the same manner as in Reference Example 1 except that the addition amount of initial addition and additional addition of t-dodecyl mercaptan was 0.18 parts by weight, respectively. The obtained graft copolymer (A-5) had a weight average molecular weight of 100,000, a graft ratio of 25%, and a refractive index of 1.536.

Reference Example 6 Vinyl copolymer (B-1)
In a 20 L autoclave, a solution prepared by dissolving 0.05 parts by weight of methyl methacrylate-acrylamide copolymer (described in Japanese Patent Publication No. 45-24151) in 165 parts by weight of pure water was stirred and stirred at 400 rpm. Replaced with nitrogen gas. Next, a monomer mixture of 4 parts by weight of acrylonitrile, 25.8 parts by weight of styrene, 55.2 parts by weight of methyl methacrylate, 0.32 parts by weight of azobisisobutyronitrile and 0.2 parts by weight of t-dodecyl mercaptan Was initially added over 30 minutes while stirring the reaction system, and the copolymerization reaction was started at 70 ° C. One hour after the addition of the monomer mixture, 5 parts by weight of styrene was added using a feed pump. Thereafter, styrene was added to the reaction system 5 parts x 2 times every 30 minutes. The temperature was raised to 100 ° C. over 60 minutes after the addition of all the monomers. After reaching the temperature, the temperature was controlled at 100 ° C. for 30 minutes, and then cooling, polymer separation, washing, and drying were performed to obtain a bead-like vinyl copolymer. The obtained vinyl copolymer (B-1) had a weight average molecular weight of 120,000 and a refractive index of 1.534.

Reference Example 7 Vinyl copolymer (B-2)
The initial monomer mixture was changed to 15 parts by weight of acrylonitrile, 15 parts by weight of styrene, and 18 parts by weight of methyl methacrylate, and the monomer mixture after 1 hour was changed to 10 parts by weight of methyl methacrylate and the monomer mixture after 30 minutes. In the same manner as in Reference Example 6, except that the monomer mixture was changed to 10 parts by weight of styrene and 10 parts by weight of methyl methacrylate, and the monomer mixture after 30 minutes was changed to 12 parts by weight of styrene and 10 parts by weight of methyl methacrylate. A bead-like vinyl copolymer was obtained. The obtained vinyl copolymer (B-2) had a weight average molecular weight of 120,000 and a refractive index of 1.530.

(Reference Example 8) Vinyl copolymer (B-3)
In the operation of changing the monomer mixture of initial addition to 9 parts by weight of acrylonitrile and 61 parts by weight of styrene, adding the monomer mixture after 1 hour to 10 parts by weight of styrene, and then adding styrene twice at 30 minute intervals thereafter. A bead-like vinyl copolymer (B-3-1) was obtained in the same manner as in Reference Example 6 except that the amount of styrene added was changed to 10 parts by weight.

  On the other hand, a monomer mixture of 100 parts by weight of methyl methacrylate, 0.32 parts by weight of azobisisobutyronitrile and 0.2 parts by weight of t-dodecyl mercaptan was added to all monomers over 30 minutes while stirring the reaction system. The copolymerization reaction was started at 70 ° C. After adding the monomer mixture, the temperature was raised to 100 ° C. over 60 minutes. After reaching the temperature for 30 minutes at 100 ° C., cooling, polymer separation, washing and drying were performed to obtain a polymethyl methacrylate homopolymer (B-3-2).

  44.8 parts by weight of the above-mentioned polymer (B-3-1) obtained by polymerization and 55.2 parts by weight of a polymethyl methacrylate homopolymer (B-3-2) were mixed to prepare beads. A vinyl copolymer (B-3) was obtained. The obtained vinyl copolymer (B-3) had a weight average molecular weight of 120,000 and a refractive index of 1.535.

(Examples 1-5, Comparative Examples 1-3)
The above-mentioned graft copolymers (A) prepared in Reference Examples 1 to 5 and vinyl polymers (B) prepared in Reference Examples 6 to 8 were blended in the blending ratios shown in Table 2, respectively, and further as additives. After adding 0.3 part by weight of t-butylhydroxytoluene and 0.3 part by weight of tri (nonylphenyl) phosphite and mixing at 23 ° C. with a Henschel mixer, the resulting mixture was passed through an extrusion temperature of 230 mm with a 40 mmφ extruder. Extruded into a gut shape at 0 ° C. and pelletized. Then using the obtained pellets. A test piece for evaluation was produced by injection molding at a molding temperature of 230 ° C. and a mold temperature of 40 ° C. Table 3 shows the results of measuring physical properties of these test pieces.

  The transparent styrenic thermoplastic resin composition obtained in the present invention is expected to be used in many fields such as automobile members, home appliances, and building materials.

Claims (5)

  A weight average particle size of 0.30 having a particle size distribution such that the particle size of 1 μm or more is 2 to 10% by weight of the whole particle and the particle size of 0.1 μm or less is 20% by weight or less of the whole particle. Contains at least an aromatic vinyl monomer (a1) and an unsaturated carboxylic acid alkyl ester monomer (a2) in the presence of 3 to 50% by weight of a styrene-butadiene rubber polymer (r) of .about.0.70 .mu.m. 10 to 100 parts by weight of graft copolymer (A) obtained by graft copolymerization of 50 to 97% by weight of monomer mixture (a), and at least aromatic vinyl monomer (b1) and unsaturated carboxylic acid In the resin composition containing 0 to 90 parts by weight of the vinyl polymer (B) obtained by polymerizing the alkyl ester monomer (b1), the ratio of the rubbery polymer (r) to the weight of the resin composition Is 3 5, wherein the percentages by weight, transparent styrene-based thermoplastic resin composition.   The transparent styrenic thermoplastic resin composition according to claim 1, wherein the graft ratio of the graft copolymer (A) is 30% or more.   Monomer mixture (a) is aromatic vinyl monomer (a1) 20 to 70% by weight, unsaturated carboxylic acid alkyl ester monomer (a2) 30 to 80% by weight, vinyl cyanide monomer The transparent styrenic heat according to claim 1 or 2, comprising 0 to 10% by weight of the body (a3) and 0 to 10% by weight of another monomer (a4) copolymerizable therewith. Plastic resin composition.   The vinyl polymer (B) is an aromatic vinyl monomer (b1) 20 to 70% by weight, an unsaturated carboxylic acid alkyl ester monomer (b2) 30 to 80% by weight, a vinyl cyanide monomer It is obtained by polymerizing 0 to 10% by weight of the body (b3) and 0 to 10% by weight of another monomer (b4) copolymerizable therewith. The transparent styrene-based thermoplastic resin composition described.   Haze is 20 or less, The transparent styrene-type thermoplastic resin composition in any one of Claims 1-4 characterized by the above-mentioned.