JP5062826B2 - Thermoplastic resin composition with excellent scratch resistance, design and impact resistance - Google Patents

Description

  The present invention relates to a thermoplastic resin composition excellent in moldability, scratch resistance, designability and impact resistance, and a molded product thereof.

  Conventionally, styrene-based resins have a good balance of molding processability and mechanical properties, and are excellent in electrical insulation, so they are used in a wide range of fields such as the electrical / electronic equipment field and OA equipment field. . However, when commercialized, the molded product obtained by molding the resin may be packed one by one with a soft non-woven fabric or the like for the purpose of preventing fine scratches, for example, when transported to the assembly line. It took time and money.

  In addition, in order to give various designs to the resin product and to prevent the product from being damaged during use, the product may be fully or partially coated. However, the coating process has a problem that the production yield is likely to decrease due to poor coating. In addition, due to the recent trend of suppressing VOC emissions, it is easy to impart design properties, such as coloring in a vivid color or deep color, or giving it a metallic or pearly appearance, with as little coating as possible. In addition, a resin that is difficult to be damaged has been desired.

  On the other hand, since styrene resins have excellent compatibility with methyl methacrylate resins by copolymerizing monomers such as styrene and acrylonitrile and methyl methacrylate, these alloys can be used for various purposes. Proposed. For example, there is a method of improving scratch resistance while maintaining transparency by mixing a styrene resin and a methyl methacrylate resin. (For example, refer to Patent Documents 1 and 2) However, these have a problem that they are remarkably inferior in impact resistance. Therefore, studies have been made to increase the impact strength by introducing a rubber component. However, for example, Patent Document 3 is inferior in design because it impairs transparency. The resin described in Patent Document 4 has a problem that the surface hardness (scratch resistance) is not sufficient and the scratch resistance as an exterior part is not sufficient.

  In addition, since the resins described in Patent Documents 5 and 6 are not sufficiently improved in impact resistance, they are necessary for housings of electric appliances, electronic devices and OA devices even if they can be used in applications where little external impact is applied. As for the strength, it is not sufficient when it falls and it becomes a problem in practical use. In general, if the molecular weight is increased in order to increase the impact strength, the moldability is remarkably lowered, and the appearance is poor, such as burns and the occurrence of silver due to thermal decomposition because the molding temperature must be significantly increased. This is not preferable because a phenomenon is likely to occur. From the above, further improvement in impact strength has been desired within a certain range of formability.

JP 58-194939 A JP-A-7-228740 Japanese Patent Laid-Open No. 11-1600 JP 2001-226547 A Japanese Patent Laid-Open No. 8-7385 JP 2006-265407 A

  An object of the present invention is to provide a thermoplastic resin composition excellent in moldability, scratch resistance, and design properties and having a practically useful impact resistance strength and a molded product thereof.

As a result of intensive studies to solve the above problems, the inventors of the present invention include a specific range of methyl acrylate in acrylonitrile-butadiene-styrene resin and methyl methacrylate-methyl acrylate resin. The inventors have found that the problem can be solved by blending a specific amount of methyl methacrylate-methyl acrylate copolymer, and have reached the present invention.
That is, the present invention relates to a thermoplastic resin composition and a molded product thereof as described below.

[1] Graft copolymer (A) obtained by graft polymerization of aromatic vinyl monomer and vinyl cyanide monomer to rubber polymer, aromatic vinyl monomer and vinyl cyanide monomer Resin composition comprising copolymer (B) obtained by copolymerization of monomer comprising monomer, and copolymer (C) obtained by copolymerization of methyl methacrylate monomer and methyl acrylate monomer (I), the reduced viscosity (ηsp / c) of the soluble component of the composition (II) comprising the components (A) and (B) is 0.60 to 1.2 dl / g, and the resin composition The ratio of the rubbery polymer in the product (I) is 8 to 13% by mass, the ratio of the copolymer (C) is 40 to 65% by mass, and methyl acrylate is added in the copolymer (C). The copolymer (C ′) containing 8 to 20% by mass is contained in the copolymer (C) in an amount of 50 to 70% by mass. A thermoplastic resin composition.
[2] A molded article comprising the thermoplastic resin composition according to [1].

  According to the present invention, it is possible to obtain a thermoplastic resin composition and a molded product having high scratch resistance, design properties, impact resistance, and moldability.

The thermoplastic resin composition (I) of the present invention contains the following (A), (B) and (C) as basic components.
Graft copolymer (A): A copolymer obtained by graft-polymerizing an aromatic vinyl monomer and a vinyl cyanide monomer to a rubbery polymer Copolymer (B): Aromatic vinyl monomer Copolymer and a monomer comprising a vinyl cyanide monomer copolymer (C): a copolymer obtained by copolymerizing a methyl methacrylate monomer and a methyl acrylate monomer Polymer Each of the above components will be described below.

<Graft copolymer (A)>
The graft copolymer (A) is obtained by graft polymerization of an aromatic vinyl monomer and a vinyl cyanide monomer to a rubber polymer.
Examples of the rubbery polymer used in the graft copolymer (A) include polybutadiene, butadiene-styrene copolymer, butadiene-acrylonitrile copolymer, butadiene-acrylic copolymer, styrene-butadiene-styrene block copolymer, Conjugated diene rubbers such as polyisoprene and styrene-isoprene copolymers, and hydrogenated products thereof, acrylic rubbers such as ethyl acrylate and butyl acrylate, ethylene-α-olefin-polyene copolymers, ethylene-α -An olefin copolymer, silicone rubber, silicone-acrylic rubber, etc. are mentioned, These can be used individually or in combination of 2 or more types. Of these, polybutadiene, polyisoprene, butadiene-styrene copolymer, butadiene-acrylonitrile copolymer, butadiene-acrylic copolymer, acrylic rubber, ethylene-α-olefin-polyene copolymer, ethylene are particularly preferable. -Α-olefin copolymer, silicone rubber, silicone-acrylic rubber.

Examples of the aromatic vinyl monomer in the graft copolymer (A) include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, ethylstyrene, pt-butylstyrene, and vinylnaphthalene. These can be used alone or in combination of two or more. Of these, styrene and α-methylstyrene are particularly preferable.
Examples of the vinyl cyanide monomer in the graft copolymer (A) include acrylonitrile and methacrylonitrile. Among these, acrylonitrile is particularly preferable.

In the graft copolymer (A), a copolymerizable monomer can be copolymerized in addition to the aromatic vinyl monomer and the vinyl cyanide monomer as long as the transparency is not inhibited. As copolymerizable monomers, acrylic esters such as methyl acrylate, ethyl acrylate and butyl acrylate, methacrylic esters of similar substitutions, acrylic acids such as acrylic acid and methacrylic acid, and N-phenyl Examples thereof include N-substituted maleimide monomers such as maleimide and N-methylmaleimide, and glycidyl group-containing monomers such as glycidyl methacrylate. Among these, methyl acrylate, ethyl acrylate, acrylic acid are particularly preferable. Butyl, methyl methacrylate, N-phenylmaleimide, glycidyl methacrylate.
The content of these monomers in the graft copolymer (A) is preferably less than 10% by mass, more preferably less than 5% by mass, and particularly preferably less than 3% by mass. When this is in this range, a composition excellent in heat resistance and design properties can be obtained.

  The volume average particle size of the rubbery polymer in the graft copolymer (A) is preferably 0.1 to 1.2 μm from the balance of mechanical strength such as impact resistance, molding processability, and appearance of the molded product. Preferably it is 0.15-0.8 micrometer, More preferably, it is 0.15-0.6 micrometer, Most preferably, it is 0.2-0.4 micrometer.

  Moreover, the graft ratio in a graft copolymer (A) becomes like this. Preferably it is 10-150 mass%, More preferably, it is 20-110 mass%, More preferably, it is 25-60 mass%. By setting the graft ratio within this range, a composition having excellent impact resistance and good moldability can be obtained. The graft ratio is defined as the weight ratio of the monomer graft copolymerized with the rubber polymer to the rubber polymer. In the measurement method, a polymer produced by a polymerization reaction is dissolved in acetone and separated into an acetone-soluble component and an insoluble component by a centrifuge. At this time, the component dissolved in acetone is a component that has not undergone graft reaction (non-graft component) among the copolymer that has undergone polymerization reaction, and the acetone insoluble component is a component that has undergone graft reaction to the rubber polymer and rubber polymer. (Graft component). Since the value obtained by subtracting the weight of the rubbery polymer from the weight of the acetone-insoluble component is defined as the weight of the graft component, the graft ratio can be determined from these values.

In the graft copolymer (A), the content of the vinyl cyanide monomer other than the rubbery polymer is preferably 15 to 27% by mass, more preferably 18 to 23% by mass. When this is in this range, it is particularly excellent in design and impact resistance.
The refractive index of the rubbery polymer is preferably 1.51 to 1.54 at 20 ° C. When it is in this range, a composition having particularly excellent design properties can be obtained.

<Copolymer (B)>
The copolymer (B) comprises an aromatic vinyl monomer and a vinyl cyanide monomer.
Examples of the aromatic vinyl monomer include styrene, α-methyl styrene, o-methyl styrene, p-methyl styrene, ethyl styrene, pt-butyl styrene, and vinyl naphthalene. These may be used alone or in combination of two or more. Can be used in combination. Of these, styrene and α-methylstyrene are particularly preferable.
Examples of the vinyl cyanide monomer include acrylonitrile and methacrylonitrile. Among them, acrylonitrile is particularly preferable.
The content of the vinyl cyanide monomer in the copolymer (B) is preferably 15 to 27% by mass. When this is in this range, it is particularly excellent in design and impact resistance.

In the copolymer (B), a copolymerizable monomer can be copolymerized in addition to the aromatic vinyl monomer and the vinyl cyanide monomer as long as the transparency is not inhibited. Examples of the copolymerizable monomer include acrylic acid esters such as methyl acrylate, ethyl acrylate, and butyl acrylate, methacrylic acid esters of similar substitutes, acrylic acids such as acrylic acid and methacrylic acid, and N- Examples thereof include N-substituted maleimide monomers such as phenylmaleimide and N-methylmaleimide, and glycidyl group-containing monomers such as glycidyl methacrylate. Among these, methyl acrylate, ethyl acrylate, acrylic Acid butyl, methyl methacrylate, N-phenylmaleimide, and glycidyl methacrylate.
The content of these monomers in the copolymer (B) is preferably less than 10% by mass, more preferably less than 5% by mass, and particularly preferably less than 3% by mass. When this is in this range, a composition excellent in heat resistance and design properties can be obtained.

<Copolymer (C)>
The copolymer (C) consists of a methyl methacrylate monomer and a methyl acrylate monomer.
In the copolymer (C), a copolymerizable monomer can be copolymerized in addition to the methyl methacrylate monomer and the methyl acrylate monomer. As copolymerizable monomers, aromatic vinyl monomers such as styrene and α-methylstyrene, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, T-butyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, (meth) acrylic acid And unsaturated carboxylic acid alkyl ester monomers such as 2,3,4,5,6-pentahydroxyhexyl and (meth) acrylic acid 2,3,4,5-tetrahydroxypentyl. A polymerized composition can be used.

  The average content of the methyl methacrylate monomer in the copolymer (C) is preferably 80 to 99.5% by mass, and more preferably 85 to 95% by mass. Furthermore, 30 to 70 mass% of the copolymer (C ′) containing 8 to 20 mass%, more preferably 8 to 14 mass% of the methyl acrylate monomer in 100 mass% of the copolymer (C). %, More preferably 40 to 60% by mass. When this is in this range, a composition having excellent moldability and impact resistance can be obtained.

  The reduced viscosity of the copolymer (C) is preferably 0.25 to 0.50 dl / g, more preferably 0.30 to 0.45 dl / g, particularly preferably 0.30 to 0.37 dl / g, It is. When this is in this range, a composition excellent in moldability and impact resistance can be obtained. The reduced viscosity can be obtained by measuring the outflow time in a Cannon-Fenske capillary at 30 ° C. of a solution obtained by dissolving 0.50 g of copolymer (C) in 100 ml of 2-butanone.

  The reduced viscosity (ηsp / c) of the soluble component of the resin composition (II) comprising the graft copolymer (A) and the copolymer (B) is 0.60 to 1.20 dl / g, preferably 0. .60 to 0.80 dl / g. When this is in this range, a composition excellent in impact resistance and moldability can be obtained. The soluble component is a component that is soluble in acetone, and can be obtained by dissolving the composition in acetone and then centrifuging it with a centrifuge to separate the supernatant. The reduced viscosity is obtained by measuring the outflow time in a Cannon-Fenske type capillary at 30 ° C. of a solution in which 0.50 g of the soluble component of the resin composition (I) is dissolved in 100 ml of 2-butanone.

The graft copolymer (A), copolymer (B), and copolymer (C) are produced by a known method such as emulsion polymerization, bulk polymerization, suspension polymerization, suspension bulk polymerization, solution polymerization, and the like. I can do it.
It is preferable that the total light transmittance in 23 degreeC in the 2.5 mm thickness flat plate of the resin composition of this invention is 75% or more, More preferably, it is 77% or more. When it is in this range, it is possible to color a vivid color or a deep color, and a composition excellent in design can be obtained.
The ratio of the rubbery polymer in the resin composition (I) is 8 to 13% by mass, preferably 8 to 12% by mass. If it is less than 8% by mass, the impact resistance is poor, and if it exceeds 13% by mass, the pencil hardness is inferior. Moreover, content of a copolymer (C) is 40-65 mass%, Preferably it is 45-55 mass%. When this is in this range, a composition excellent in moldability, scratch resistance, designability, and impact resistance can be obtained.

There are no particular restrictions on the method of mixing the composition comprising the graft copolymer (A) / copolymer (B) / copolymer (C) or the copolymer (B) / copolymer (C) in the present invention. Although not known, a known melt mixing method can be used. Specific examples include batch kneaders such as mixing rolls, Banbury mixers, and pressure kneaders, and continuous kneaders such as single screw extruders and twin screw extruders.
Moreover, there is no restriction | limiting in particular in the order of kneading | mixing, For example, the method etc. which knead | mix the whole quantity collectively are mentioned.
For the molding of the present invention, a known method generally used for molding a thermoplastic resin, for example, injection molding, extrusion molding, blow molding, inflation molding, vacuum molding, press molding or the like can be used.

  In the present invention, known additives such as plasticizers, lubricants (for example, higher fatty acids and their metal salts, higher fatty acid amides, etc.), heat stabilizers, antioxidants (for example, phenol-based, phosphite-based) Thiodibropropionic acid ester type thioether, etc.), weathering agents (eg, benzotriazole, benzophenone, salicylate, cyanoacrylate, oxalic acid derivatives, hindered amines, etc.), flame retardant aids (eg, antimony trioxide) Antimony pentoxide, etc.), antistatic agents (for example, polyamide elastomers, quaternary ammonium salts, pyridine derivatives, aliphatic sulfonates, aromatic sulfonates, aromatic sulfonate copolymers, sulfate salts, Polyhydric alcohol partial ester, alkyldiethanolamine, alkyldiethanolamide Polyalkylene glycol derivatives, betaines, imidazoline derivatives, etc.), antibacterial agents, antifungal agents, slidability improvers (for example, hydrocarbons such as low molecular weight polyethylene, higher alcohols, polyhydric alcohols, polyglycols, polyglycerols, Higher fatty acid, higher fatty acid metal salt, fatty acid amide, ester of fatty acid and aliphatic alcohol, full or partial ester of fatty acid and polyhydric alcohol, full or partial ester of fatty acid and polyglycol, silicone series, fluororesin Etc.) can be blended at an arbitrary ratio according to the purpose.

For the purpose of imparting design properties, known colorants such as inorganic pigments, organic pigments, metallic pigments, and dyes can be added.
Examples of inorganic pigments include titanium oxide, carbon black, titanium yellow, iron oxide pigments, ultramarine blue, cobalt blue, chromium oxide, spinel green, lead chromate pigments, and cadmium pigments.

  Examples of organic pigments include azo pigments such as azo lake pigments, benzimidazolone pigments, diarylide pigments, and condensed azo pigments, phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green, isoindolinone pigments, quinophthalone pigments, quinacridone pigments, and perylenes. Examples thereof include condensed polycyclic pigments such as pigments, anthraquinone pigments, perinone pigments, and dioxazine violet.

  Examples of metallic pigments include flake-like aluminum metallic pigments, spherical aluminum pigments used to improve the weld appearance, mica powder for pearl-like metallic pigments, and other polyhedral particles of inorganic substances such as glass. Are coated with plating or sputtering.

Examples of dyes include nitroso dyes, nitro dyes, azo dyes, stilbene azo dyes, ketoimine dyes, triphenylmethane dyes, xanthene dyes, acridine dyes, quinoline dyes, methine / polymethine dyes, thiazole dyes, indamine / indophenol dyes, azines Examples thereof include dyes, oxazine dyes, thiazine dyes, sulfur dyes, amino ketone / oxyketone dyes, anthraquinone dyes, indigoid dyes, and phthalocyanine dyes.
These colorants can be used alone or in combination of two or more.

Hereinafter, the present invention will be specifically described with reference to examples. Moreover, the evaluation in an Example was performed in accordance with the following method.
(1) Notched Charpy impact strength Evaluated according to ISO179. 10 kJ / m ² or more was accepted.
(2) Deflection temperature under load (1.8 MPa load)
Evaluation was performed according to ISO75-1,2. 70 degreeC or more was set as the pass.
(3) Melt volume flow rate According to ISO1133, it evaluated by 220 degreeC and the load 98N. 7 g / 10 min or more was regarded as acceptable.
(4) Total light transmittance Using an injection molding machine, a flat plate of 5 cm × 9 cm and a thickness of 2.5 mm was injection molded at a cylinder temperature = 240 ° C. and a mold temperature = 60 ° C. Using this flat plate, evaluation was performed according to ASTM D1003. More than 75% was accepted.
(5) Pencil hardness A flat plate was prepared in the same manner as in (4) and evaluated according to JIS K5400 pencil scratch value. (Pencil: JIS S6006 regulations, Weight: 1.0 kg, 45 ° angle between test piece and pencil lead)
The pencil hardness becomes harder in the order of 2B, B, HB, F, H, 2H, 3H, and is less likely to be damaged. A pencil whose hardness was higher than F was determined to be acceptable.

[Production Example 1]
(Production of graft copolymer (A-1))
To 100 parts by mass of polybutadiene rubber latex (volume average particle size = 0.25 μm, solid content = 45% by mass measured with a Microtrac particle size analyzer “nanotrac 150” manufactured by Nikkiso Co., Ltd.) Mass parts and 45 parts by mass of deionized water were added, and the gas phase part was purged with nitrogen, and then the temperature was raised to 55 ° C. Subsequently, while the temperature was raised to 70 ° C. over 1.5 hours, a simple substance comprising 11 parts by mass of acrylonitrile, 44 parts by mass of styrene, 0.5 parts by mass of terleaded decyl mercaptan, and 0.15 parts by mass of cumene hydroperoxide. Sodium formaldehyde sulfoxylate 0.2 parts by mass, ferrous sulfate 0.004 parts by mass, ethylenediaminetetraacetic acid disodium salt 0.04 parts by mass are dissolved in a monomer mixture and 22 parts by mass of deionized water. The aqueous solution was added over 4 hours. One hour after completion of the addition, the polymerization reaction was completed while controlling the reaction vessel at 70 ° C.

  After adding a silicone resin defoamer and a phenolic antioxidant emulsion to the ABS latex thus obtained, solidify by adding an aqueous aluminum sulfate solution, and after sufficient dehydration and washing with water And dried to obtain a graft copolymer (A-1). As a result of composition analysis using a Fourier transform infrared spectrophotometer (FR-IR) (manufactured by JASCO Corporation), the composition ratio of the copolymer was 10.9% by mass of acrylonitrile and 45.5% by mass of butadiene. And 43.6% by mass of styrene. The graft ratio was 40% by mass, and the reduced viscosity (0.50 g / 100 ml, measured in a 2-butanone solution at 30 ° C.) of the non-grafted component (acetone soluble component) was 0.33 dl / g.

[Production Example 2]
(Production of copolymer (B-1))
In the method described in Example 1 of Japanese Examined Patent Publication No. 6-96625, acrylonitrile and styrene are used as a solvent, and secondary butyl alcohol is used as a solvent. The above mixed solution is continuously added to the polymerization reactor, and the temperature of the polymerization meter is adjusted. The polymerization reaction was carried out at 140 to 160 ° C. Then, the unreacted monomer was removed under vacuum and the solid powder of the copolymer (B-1) was obtained. As a result of composition analysis using a Fourier transform infrared spectrophotometer (FR-IR) (manufactured by JASCO Corporation), the composition of the copolymer was 20.8% by mass of acrylonitrile and 79.2% by mass of styrene. there were. The reduced viscosity was 0.67 dl / g.

[Production Example 3]
<Production of copolymer (B-2)>
In the same manner as in Production Example 2, a copolymer (B-2) was obtained. The copolymer was 25.5% by mass of acrylonitrile and 74.5% by mass of styrene. The reduced viscosity was 0.73 dl / g.

[Production Example 4]
<Production of copolymer (B-3)>
In the same manner as in Production Example 2, a copolymer (B-3) was obtained. The copolymer was 21.2% by mass of acrylonitrile and 78.8% by mass of styrene. The reduced viscosity was 0.81 dl / g.

[Production Example 5]
<Production of copolymer (B-4)>
A copolymer (B-4) was obtained in the same manner as in Production Example 2. The copolymer was 20.2% by mass of acrylonitrile and 79.8% by mass of styrene. The reduced viscosity was 0.50 dl / g.

[Production Example 6]
<Production of copolymer (C-1)>
1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane was added to a monomer mixture consisting of 68.6% by weight of methyl methacrylate, 1.4% by weight of methyl acrylate, and 30% by weight of ethylbenzene. 150 ppm and 1500 ppm of n-octyl mercaptan were added and mixed uniformly. This solution is continuously supplied to a sealed pressure resistant reactor having an internal volume of 10 liters, polymerized with stirring at an average temperature of 135 ° C. and an average residence time of 2 hours, and then continuously sent to a storage tank connected to the reactor. The volatile components were removed under reduced pressure, and the mixture was further transferred to the extruder in a molten state. Here, lauric acid and stearyl alcohol were quantitatively supplied from an additive inlet connected to the extruder in a melted state at 90 ° C. to obtain copolymer (C-1) pellets. The reduced viscosity of this copolymer is 0.35 dl / g, and its composition was analyzed using a pyrolysis gas chromatography method. As a result, methyl methacrylate units / methyl acrylate units = 98.0 / 2.0 (weight ratio). The result was obtained. Furthermore, when lauric acid and stearyl alcohol in the resin composition were quantified, the results were 0.03 and 0.1 parts by mass, respectively, per 100 parts by mass of the resin composition.

[Production Example 7]
<Production of copolymer (C-2)>
Amount of methyl methacrylate 63.0% by mass, methyl acrylate 7% by mass, ethylbenzene 30% by mass, and 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, and n-octyl mercaptan A copolymer (C-2) was obtained in the same manner as in Production Example 6 except that was changed. The reduced viscosity of this copolymer is 0.32 dl / g, and its composition was analyzed using a pyrolysis gas chromatography method. As a result, methyl methacrylate units / methyl acrylate units = 90.0 / 10.0 (weight ratio). Met.

[Production Example 8]
<Production of copolymer (C-3)>
Methyl methacrylate 59.5% by weight, methyl acrylate 10.5% by weight, ethylbenzene 30% by weight, and 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, and n-octyl mercaptan A copolymer (C-3) was obtained in the same manner as in Production Example 6 except that the amount of was changed. The reduced viscosity of this copolymer is 0.30 dl / g, and its composition was analyzed using a pyrolysis gas chromatography method. As a result, methyl methacrylate units / methyl acrylate units = 85.0 / 15.0 (weight ratio). Met.

[Production Example 9]
<Production of copolymer (C-4)>
Methyl methacrylate 52.5% by mass, methyl acrylate 17.5% by mass, ethylbenzene 30% by mass, and 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, and n-octyl mercaptan A copolymer (C-4) was obtained in the same manner as in Production Example 6 except that the amount of was changed. The reduced viscosity of this copolymer is 0.28 dl / g, and its composition was analyzed by pyrolysis gas chromatography. As a result, methyl methacrylate unit / methyl acrylate unit = 75.0 / 25.0 (weight ratio) Met.

[Production Example 10]
<Production of copolymer (C-5)>
Methyl methacrylate 66.0% by weight, methyl acrylate 4.0% by weight, ethylbenzene 30% by weight, and 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane, and n-octyl mercaptan A copolymer (C-5) was obtained in the same manner as in Production Example 6 except that the amount of was changed. The reduced viscosity of this copolymer is 0.34 dl / g, and its composition was analyzed using a pyrolysis gas chromatography method. As a result, methyl methacrylate units / methyl acrylate units = 94.3 / 5.7 (weight ratio). Met.

[Example 1]
Graft copolymer (A-1) 20 parts by mass, copolymer (B-1) 30 parts by mass, copolymer (C-1) 25 parts by mass, sufficiently dried and moisture-removed (C-2) After mixing 25 parts by mass, this was put into a hopper and using a twin screw extruder (PCM-30, L / D = 28, manufactured by Ikekai Tekko Co., Ltd.), the cylinder set temperature Kneading was carried out under the conditions of 250 ° C., screw rotation speed 150 rpm, and kneading resin discharge speed 15 kg / hr, and resin pellets were obtained, and each characteristic was evaluated. The evaluation results are shown in Table 1.
[Examples- 6 , Comparative Examples 1-8 , Reference Example 1 ]
Each component was mix | blended with the composition ratio shown to Table 1, 2, the resin pellet was obtained like Example 1, and evaluation was performed. The evaluation results are shown in Tables 1-2.

Examples 1 to 6 are excellent in balance between mechanical properties such as impact resistance (Charpy impact strength), heat resistance (deflection temperature under load), moldability (melt volume flow rate), and scratch resistance (pencil hardness). Furthermore, since it has a high light transmittance (total light transmittance), it is possible to color a bright color or a deep color.

  By using the composition of the present invention, a molded product having an excellent balance between mechanical properties and scratch resistance and having high design properties can be obtained.

Claims (2)

From a graft copolymer (A) obtained by graft-polymerizing an aromatic vinyl monomer and a vinyl cyanide monomer to a rubber polymer, an aromatic vinyl monomer and a vinyl cyanide monomer A resin composition (I) comprising a copolymer (B) obtained by copolymerization of a monomer and a copolymer (C) obtained by copolymerization of a methyl methacrylate monomer and a methyl acrylate monomer. The reduced viscosity (ηsp / c) of the soluble component of the composition (II) comprising the components (A) and (B) is 0.60 to 1.20 dl / g, and the resin composition (I ) Is a rubber polymer in a proportion of 8 to 13% by mass, a copolymer (C) in a proportion of 40 to 65% by mass, and the copolymer (C) contains 8 to 20 methyl acrylate. copolymer containing mass% (C ') in the copolymer (C) and comprising 50 to 70 wt% The thermoplastic resin composition that.   A molded article comprising the thermoplastic resin composition according to claim 1.