JP2009067970A - Thermoplastic resin composition with excellent damage resistance, design property, and impact resistance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoplastic resin composition excellent in damage resistance, design properties, impact resistance. <P>SOLUTION: The thermoplastic resin composition is a resin composition (I) comprising a graft copolymer (A) prepared by graft polymerization of an aromatic vinyl-based monomer and a vinyl cyanide-based monomer to a butadiene-based rubber polymer, a copolymer (B) prepared by copolymerization of monomers consisting of an aromatic vinyl-based monomer and vinyl cyanide-based monomers, and a copolymer (C) prepared by copolymerization of methyl methacrylate monomers and methyl acrylate monomers. A ratio of vinyl cyanide to the total of the vinyl cyanide and aromatic vinyl in soluble components of a composition (I) consisting of the components (A) and (B) is 15-27 mass%. A ratio of the methyl methacrylate in the copolymer (C) is 90-99.5 mass%. A ratio of the rubber polymer in the resin composition (I) is 4-8 mass%. A ratio of the copolymer (C) is 70-90 mass%. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a thermoplastic resin composition excellent in scratch resistance and design properties and imparting 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, styrene resins have excellent compatibility with methyl methacrylate resins by copolymerizing styrene and monomers such as acrylonitrile and methyl methacrylate, so 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, and the resins described in Patent Documents 4 and 5 have a problem that the surface hardness (scratch resistance) is not sufficient and the scratch resistance as an exterior part is not sufficient. there were.

  In particular, if the composition does not contain any rubber component, it will be cracked when released from the mold in injection molding, or if it is a molded product with a claw-like part such as a snap fit, There is a problem that it breaks from the base at the time of assembly or by vibration during transportation, and it has been desired to provide impact resistance while maintaining as high a scratch resistance and design as possible.

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

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

As a result of diligent studies to solve the above-mentioned problems, the present inventors have determined that a graft copolymer obtained by graft polymerization of an aromatic vinyl monomer and a vinyl cyanide monomer to a butadiene rubber polymer. Copolymer (B) obtained by copolymerizing monomer (A) with an aromatic vinyl monomer and a vinyl cyanide monomer, methyl methacrylate monomer and methyl acrylate monomer In the resin composition (I) comprising the copolymer (C) obtained by copolymerizing the polymer, the vinyl cyanide monomer in the soluble component of the composition (II) comprising the components (A) and (B) The ratio of the vinyl cyanide monomer to the total of the monomer and the aromatic vinyl monomer is set to a specific value, and the rubber polymer blend ratio and the copolymer (C) blend ratio are specified. Find out that the problem can be solved by setting the value It has reached the light.
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 butadiene rubber polymer, aromatic vinyl monomer and vinyl cyanide A copolymer (B) obtained by copolymerizing a monomer comprising a monomer and a copolymer (C) obtained by copolymerizing a methyl methacrylate monomer and a methyl acrylate monomer. Cyanation with respect to the total of vinyl cyanide monomer and aromatic vinyl monomer in the soluble component of composition (II) which is resin composition (I) and comprises component (A) and component (B) The proportion of the vinyl monomer is 15 to 27% by mass, the proportion of methyl methacrylate in the copolymer (C) is 90 to 99.5% by mass, and the rubbery material in the resin composition (I) The ratio of the polymer is 4 to 8% by mass, and the ratio of the copolymer (C) is 7 The thermoplastic resin composition characterized in that it is 90 mass%.
[2] The thermoplastic composition according to [1], wherein the total amount of the inorganic pigment, the organic pigment, and the carbon black contained as the colorant is 0.3% by mass or less. Resin composition,
[3] A colored composition, wherein the total amount of organic dyes contained as the colorant is 0.1% by mass or more, and the total amount of inorganic pigments, organic pigments, and carbon black is 0.2% by mass or less The thermoplastic resin composition according to [1], characterized in that:
[4] A molded article comprising the thermoplastic resin composition according to any one of [1] to [3].
[5] The molded article according to [4], which is obtained by injection molding in a state where the temperature of the mold cavity surface is 70 ° C. or higher at the time of injection.
[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 excellent in scratch resistance and design properties and imparting impact resistance, and a molded product thereof.

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 butadiene rubber polymer Copolymer (B): Aromatic vinyl When a monomer comprising a monomer and a vinyl cyanide monomer is copolymerized, copolymer copolymer (C) is obtained by copolymerizing methyl methacrylate monomer and methyl acrylate monomer. Hereinafter, each said component is demonstrated.

<Graft copolymer (A)>
The graft copolymer (A) is obtained by graft polymerization of an aromatic vinyl monomer and a vinyl cyanide monomer to a butadiene rubber polymer.
Examples of the rubbery polymer used for 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 -Olefin copolymer, silicone rubber, silicone-acrylic rubber and the like can be mentioned, and these can be used alone or in combination of two or more, but it is essential to contain a component containing butadiene. Of these, polybutadiene, polyisoprene, butadiene-styrene copolymer, butadiene-acrylonitrile copolymer, and butadiene-acrylic copolymer are preferably used alone.

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.
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.

  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.
Further, the vinyl cyanide monomer based on the total of vinyl cyanide monomer and aromatic vinyl monomer in the soluble component of the composition (II) comprising the copolymer (A) component and the component (B) The proportion of the body is preferably 15 to 27% by mass, particularly preferably 18 to 23% by mass. When this is in this range, the design is particularly excellent.

<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 90 to 99.5% by mass, and more preferably 95 to 99.5% by mass. If the content of the methyl methacrylate monomer is small, the pencil hardness may decrease.
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.
The total light transmittance at 23 ° C. of a 2.5 mm thick flat plate of the uncolored product of the resin composition (I) of the present invention needs to be 40% or more, particularly preferably 50% 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 4 to 8% by mass. If it is less than 4% by mass, the impact resistance is inferior, and if it exceeds 8% by mass, the pencil hardness is inferior. Moreover, content of a copolymer (C) is 70-90 mass%, Preferably it is 75-85 mass%. When this is in this range, a composition excellent in scratch resistance, impact resistance and designability 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, injection compression molding, extrusion molding, blow molding, inflation molding, vacuum molding, press molding, or the like is used. I can do it. At this time, injection molding or injection compression molding is often used, but this does not limit the mold temperature in this case. However, it is preferable to raise the mold temperature, especially when it is colored black. The surface temperature of the mold cavity is preferably 70 ° C. or higher, more preferably 80 ° C. or higher, particularly preferably 100 ° C. or higher as the temperature at the time of resin injection. For example, if the mold temperature is raised above the melting temperature of the resin such as 120 ° C., it takes a lot of time for solidification by cooling, and there is a high possibility that defects such as sink marks and release defects will occur. By using a technique (for example, Japanese Patent Laid-Open Nos. 09-314628 and 2001-191378) in which the temperature of the cavity surface of the mold is raised and lowered within the molding cycle, the above-mentioned problems can be solved, and further, the weld line Since it is possible to obtain a molded product that is better in design than the disappearance of, etc., it is particularly preferable.

  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, zinc oxide 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 include dyes, oxazine dyes, thiazine dyes, sulfur dyes, aminoketone / oxyketone dyes, anthraquinone dyes, indigoid dyes, phthalocyanine dyes, perylene dyes, and perinone dyes.

  These colorants can be used alone or in combination of two or more. Of these, in particular, when it is desired to be colored black, a deeper black can be developed by combining black, red, green and yellow dyes to develop black.

In the present invention, the colorant that can be used is not particularly limited, but in order to enhance the effect of the present invention, the total amount of inorganic pigment, organic pigment, and carbon black is preferably 0.3% by mass or less. More preferably, it is 0.1% by mass or less, and particularly preferably 0.01% by mass or less.
Further, the total amount of the organic dye contained as a colorant is 0.1% by mass to 2% by mass, preferably 0.1% by mass to 1% by mass, and more preferably 0.2% by mass to 0.5% by mass. I need a thing. By doing so, it is possible to develop a deep jet black tone that does not differ from ordinary transparent resins. Below 0.1% by mass, jetness is insufficient. On the other hand, if the amount is 2% by mass or more, the dye is expensive and not only economically problematic, but also an appearance defect phenomenon is likely to occur due to mold deposit at the time of molding.

  As for the classification of inorganic pigments, organic pigments, and organic dyes here, voluntary standards for food containers and packaging made of synthetic resins such as polyolefins issued by the Sanitation Council for Polyolefins (Part 2: Positive List, 2-3 Coloring Materials) Although it is based on the classification described in the 8th edition, it does not limit the types of dyes and pigments that can be used including carbon black.

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. ² kJ / m ² or more was accepted.
(2) 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 = 70 ° C. Using this flat plate, evaluation was performed according to ASTM D1003. More than 40% was accepted.

(3) Pencil hardness A flat plate was prepared in the same manner as in (2) and evaluated according to the 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 harder than this, including 2H, was accepted.

(4) Black tone For each natural product, Disperse Red 22, Solvent Yellow 93 and Solvent Green 3 were each added by 0.1% by mass and extruded and kneaded, and then the same as (2) (the mold temperature was the same) A flat plate was prepared under the conditions described in the examples, and the blackness was visually determined. (The degree of blackness is higher in the order of ◎>○>△> ×). However, in Example 9, carbon black (CB: trade name # 980) manufactured by Mitsubishi Chemical Corporation was dispersed by 1: 1 with ethylene bis fatty acid amide (trade name: EB-FF) manufactured by Kao Corporation. The determination was made with a flat plate obtained from a sample obtained by adding 0.5% by mass as carbon black and extrusion kneading.

(5) Measurement of the ratio of soluble vinyl cyanide in composition (II) For each natural product, weigh 1 g after drying at 80 ° C. for 2 hours or more and place it in a centrifuge tube of about 20 ml. After shaking with a shaker for 2 hours, a well-balanced centrifuge tube is set diagonally on the rotor of the centrifuge and centrifuged. (Example: Hitachi CP56G is used. 18000 rotation for 50 minutes, etc.) After centrifugation, the supernatant is gradually decanted to separate only soluble components. The separated soluble component is dried at 80 ° C. to evaporate acetone, then dried at 105 ° C. for 15 minutes, and further dried at 105 ° C. for 30 minutes in a vacuum dryer.
The soluble fraction obtained in this manner was used to determine the aromatic vinyl / vinyl cyanide absorbance ratio using a Fourier transform infrared spectrophotometer (FR-IR) (manufactured by JASCO Corporation), Based on a calibration curve obtained from a standard sample whose ratio is known by analysis or the like, the ratio [mass%] of vinyl cyanide to the total of vinyl cyanide and aromatic vinyl in the soluble component of composition (II) is determined. (The manufacturing examples described below are also the same.)

[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 graft copolymer (A-2)>
In the same manner as in Production Example 1, a graft copolymer (A-2) was obtained. As a result of composition analysis of this copolymer, it was 13.7% by mass of acrylonitrile, 45.0% by mass of butadiene, and 41.3% by mass of styrene. The graft ratio was 43% by mass, and the reduced viscosity (0.50 g / 100 ml, measured in 30 ° C. in 2-butanone solution) of the non-grafted component (acetone soluble component) was 0.32 dl / g.

[Production Example 3]
<Production of graft copolymer (A-3)>
In the same manner as in Production Example 1, a graft copolymer (A-3) was obtained. As a result of composition analysis of this copolymer, it was 16.6% by mass of acrylonitrile, 44.8% by mass of butadiene, and 38.6% by mass of styrene. The graft ratio was 45% 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 0.30 dl / g.

[Production Example 4]
(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 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 5]
<Production of copolymer (B-2)>
In the same manner as in Production Example 2, a copolymer (B-2) was obtained. The copolymer was 25.4% by mass of acrylonitrile and 74.6% by mass of styrene. The reduced viscosity was 0.62 dl / g.

[Production Example 6]
<Production of copolymer (B-3)>
In the same manner as in Production Example 2, a copolymer (B-3) was obtained. The copolymer was 30.2% by mass of acrylonitrile and 69.8% by mass of styrene. The reduced viscosity was 0.58 dl / g.

[Production Example 7]
<Production of copolymer (C-1)>
1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane was added to a monomer mixture consisting of 68.5% by mass of methyl methacrylate, 1.5% by mass of methyl acrylate, and 30% by mass 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 was 0.29 dl / g, and composition analysis was performed using a pyrolysis gas chromatography method. As a result, methyl methacrylate units / methyl acrylate units = 97.9 / 2.1 (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 8]
<Production of copolymer (C-2)>
Methyl methacrylate 63.5% by mass, methyl acrylate 6.5% 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 the amount of 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 = 90.7 / 9.3 (weight ratio). Met.

[Production Example 9]
<Production of copolymer (C-3)>
Methyl methacrylate 61.0% by weight, methyl acrylate 39.5% 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 was 0.36 dl / g, and composition analysis was performed using a pyrolysis gas chromatography method. As a result, methyl methacrylate units / methyl acrylate units = 87.2 / 12.8 (weight ratio). Met.

[Example 1]
After mixing 10 parts by weight of the graft copolymer (A-1), 15 parts by weight of the copolymer (B-1), and 75 parts by weight of the copolymer (C-1) that have been sufficiently dried and subjected to moisture removal. , This was put into a hopper, and using a twin screw extruder (PCM-30, L / D = 28, manufactured by Ikekai Tekko Co., Ltd.), a cylinder set temperature of 250 ° C., a screw rotation speed of 150 rpm, and discharge of kneaded resin Kneading was performed at a speed of 15 kg / hr to obtain resin pellets, and each characteristic was evaluated. The evaluation results are shown in Table 1.
[Examples 2-9, Comparative Examples 1-6]
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.

  In Examples 1 to 9, the balance of impact resistance (Charpy impact strength) and scratch resistance (pencil hardness) to the extent that cracks do not occur during mold release, snap-fit attachment, and transportation while maintaining the strength of the claw In addition, since it has a light transmittance (total light transmittance) of a certain level or more, it can be colored in a vivid color or a deep color.

On the other hand, since the amount of the rubber-like polymer in the graft copolymer (A) is not less than the numerical range specified in the present invention, Comparative Example 1 is not suitable for pencil hardness.
In Comparative Example 2, since the amount of the rubbery polymer in the graft copolymer (A) is less than the numerical range defined in the present invention, the impact strength is not suitable.
In Comparative Example 3, since the ratio of the copolymer (C) is less than the numerical range defined in the present invention, the pencil hardness is not suitable.
In Comparative Example 4, since the proportion of the copolymer (C) exceeds the numerical range defined in the present invention, the proportion of the copolymer (A) falls below, and as a result, the impact strength is not suitable.
In Comparative Example 5, the ratio of vinyl cyanide to the total of vinyl cyanide and aromatic vinyl in the soluble component of the composition (II) comprising the copolymer (A) component and the component (B) is a numerical value defined by the present invention. Since it is less than the range, the total light transmittance is not suitable, and as a result, the black tone is inferior.
In Comparative Example 6, since the ratio of methyl methacrylate in the copolymer (C) is less than the numerical range specified in the present invention, the pencil hardness is not suitable.

  By using the thermoplastic resin composition of the present invention, a molded article having excellent scratch resistance and design properties and imparting impact resistance can be obtained.

Claims (5)

  Graft copolymer (A) obtained by graft-polymerizing aromatic vinyl monomer and vinyl cyanide monomer to butadiene rubber polymer, aromatic vinyl monomer and vinyl cyanide monomer A resin composition comprising a copolymer (B) obtained by copolymerizing a monomer comprising a polymer and a copolymer (C) obtained by copolymerizing a methyl methacrylate monomer and a methyl acrylate monomer (I), a vinyl cyanide monomer based on the total of vinyl cyanide monomer and aromatic vinyl monomer in the soluble component of the composition (II) comprising the components (A) and (B) The proportion of the monomer is 15 to 27% by mass, the proportion of methyl methacrylate in the copolymer (C) is 90 to 99.5% by mass, and the rubber polymer in the resin composition (I) The proportion is 4 to 8% by mass, and the proportion of the copolymer (C) is 70 to 9 The thermoplastic resin composition, wherein the percentages by weight.   2. The thermoplastic resin composition according to claim 1, wherein the total amount of the inorganic pigment, the organic pigment, and the carbon black contained as the colorant is 0.3% by mass or less. .   A colored composition, wherein the total amount of organic dyes contained as the colorant is 0.1% by mass or more and 2% by mass or less, and the total amount of inorganic pigment, organic pigment, and carbon black is 0.2% by mass. The thermoplastic resin composition according to claim 1, wherein:   A molded article comprising the thermoplastic resin composition according to any one of claims 1 to 3.   5. The molded product according to claim 4, wherein the molded product is obtained by injection molding in a state where the temperature of the mold cavity surface is 70 ° C. or more at the time of injection.