JP2007039488A - Transparent scratch resistant thermoplastic resin composition and molded article composed thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transparent thermoplastic resin composition having excellent surface hardness and scratch resistance and a molded article. <P>SOLUTION: The resin composition is obtained by incorporating a specific polyorganosiloxane oil into a rubber reinforced thermoplastic resin composition having transparency, and the amount of the polyorganosiloxane oil (C) incorporated is specified with respect to the amount of a rubbery polymer (a) and the reduced viscosity of a vinyl copolymer (B). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rubber-reinforced styrene-based resin composition having transparency and a molded article comprising the same, and more specifically, a transparent heat excellent in balance of transparency, scratch resistance and impact resistance, and excellent in moldability. The present invention relates to a plastic resin composition and a molded article.

  Styrenic resins typified by rubber-reinforced styrenic resins have excellent mechanical properties, molding processability, and appearance characteristics, so they can be used in a wide range of fields, including household electrical equipment, OA equipment, and general merchandise. in use. Furthermore, transparency can be imparted to the rubber-reinforced styrene resin by copolymerizing an appropriate amount of an unsaturated carboxylic acid alkyl ester represented by a (meth) acrylic acid ester monomer. The composition is used in external parts such as a housing typified by the above-mentioned household electric appliance. However, due to the recent demand for improved design in product design, scratch resistance is required when using transparent resin for external parts, but rubber such as polymethyl methacrylate has excellent scratch resistance. The non-reinforced transparent resin has low impact strength, and cannot maintain the strength of a molded product that has been thinned such as a crack at the time of mold release and a housing material.

  As a technique for improving the scratch resistance of a conventional resin, a technique of adding polymethyl methacrylate to an ABS resin is disclosed (for example, see Patent Document 1). However, the transparency is impaired due to the difference in refractive index, and use in applications requiring transparency is not preferable.

  In general, it is known that the scratch resistance is improved by reducing the blending amount of the rubber polymer of the rubber-reinforced styrene resin having transparency. However, if the blending amount of the rubbery polymer is reduced in order to develop sufficient scratch resistance, the impact resistance is lowered, so that it cannot be used as a housing material.

  On the other hand, in order to improve impact resistance without impairing transparency, a technique for blending polyorganosiloxane oil has been disclosed (see, for example, Patent Document 2). However, the resin composition described in this document does not disclose a technique for improving scratch resistance and surface hardness required for a housing or the like.

  Moreover, the technique of mix | blending a polysiloxane compound in order to improve a scratch resistance by providing slidability, without impairing the transparency of a transparent thermoplastic resin composition is disclosed (for example, refer patent document 3). . However, in this document, the blending ratio of the rubber polymer, the vinyl copolymer and the polysiloxane compound is not clarified, and the surface hardness cannot be improved.

Therefore, in the field of the conventional transparent thermoplastic resin composition, a technique for improving scratch resistance and surface hardness without impairing transparency and impact resistance has not been established.
Japanese Patent Laid-Open No. 01-278553 JP 2001-200134 A JP 2003-20378 A

  The present invention has been achieved as a result of studying the solution of the problems in the prior art described above as an issue. Accordingly, an object of the present invention is to provide a transparent rubber reinforced with high transparency and impact resistance required for a housing material, etc., and at the same time, having excellent scratch resistance and surface hardness, and excellent molding processability. An object of the present invention is to provide a styrenic thermoplastic resin composition and a molded article comprising them.

  As a result of intensive studies, the present inventors have found that in a resin composition obtained by blending a specific polyorganosiloxane oil with a rubber-reinforced styrene-based thermoplastic resin composition having transparency, the rubber polymer (a) By specifying the blending amount and the blending amount of the polyorganosiloxane oil (C) with respect to the reduced viscosity of the vinyl copolymer (B), it has high transparency and at the same time excellent surface hardness and scratch resistance, housing material The present inventors have found that a transparent rubber-reinforced styrene-based thermoplastic resin composition having impact resistance required for the above and the like and excellent molding processability can be obtained.

That is, the present invention
Graft copolymer containing rubbery polymer (a), aromatic vinyl monomer (b), vinyl cyanide monomer (c) and unsaturated carboxylic acid alkyl ester monomer (d) A vinyl copolymer (B) containing (A), an aromatic vinyl monomer (b), a vinyl cyanide monomer (c) and an unsaturated carboxylic acid alkyl ester monomer (d) ) And a polyorganosiloxane oil (C), which is a thermoplastic resin composition comprising a rubber polymer (A) and a vinyl polymer (B) in a total amount of rubber polymer (A) and vinyl copolymer (B). The blending amount P of a) is in the range of 2.5 to 11.5% by weight, the reduced viscosity R of the vinyl copolymer (B) is in the range of 0.27 to 0.36 dl / g, and The amount Q (wt%) of the organosiloxane oil (C) is
Formula (1): (12-31R) / (2P) ≦ Q ≦ 1.2
And the total light transmittance at a thickness of 3 mm measured at 23 ° C. is 80% or more.

  According to the present invention, it is possible to obtain a transparent rubber-reinforced styrene thermoplastic resin composition having excellent scratch resistance and surface hardness without impairing the transparency and impact resistance of a rubber-reinforced styrene resin having transparency. it can. This makes it suitable for use in thin molded articles such as housing materials such as household electrical equipment, OA equipment, and general miscellaneous goods that have been difficult to use in the prior art.

  Hereinafter, the transparent thermoplastic resin composition of the present invention will be described in detail.

  The present invention is a thermoplastic resin composition comprising a graft copolymer (A), a vinyl copolymer (B), and a polyorganosiloxane oil (C).

  The graft copolymer (A) in the present invention comprises a rubbery polymer (a), an aromatic vinyl monomer (b), a vinyl cyanide monomer (c), and an unsaturated carboxylic acid alkyl ester monomer. It contains a monomer (d). Moreover, it contains the other vinyl-type monomer (e) copolymerizable with these as needed.

  The vinyl copolymer (B) in the present invention comprises an aromatic vinyl monomer (b), a vinyl cyanide monomer (c), and an unsaturated carboxylic acid alkyl ester monomer (d). Is included. Moreover, it contains the other vinyl-type monomer (e) copolymerizable with these as needed.

  The rubbery polymer (a) used in the graft copolymer (A) is not particularly limited, but diene rubber, acrylic rubber, ethylene rubber, and the like can be used. Specific examples of these rubber-like polymers include polybutadiene, styrene-butadiene copolymer, block copolymer of styrene butadiene, acrylonitrile-butadiene copolymer, butyl acrylate-butadiene copolymer, polyisoprene, butadiene-methacrylic. Examples include an acid methyl copolymer, a butadiene-ethyl acrylate copolymer, an ethylene-propylene-diene copolymer, an ethylene-isoprene copolymer, and an ethylene-methyl acrylate copolymer. Of these rubber polymers, polybutadiene, styrene-butadiene copolymer, styrene-butadiene block copolymer or acrylonitrile-butadiene copolymer are particularly preferably used from the viewpoint of impact resistance.

  These rubbery polymers can be used in one kind or a mixture of two or more, but when used in a mixture of two or more kinds, an Abbe refractometer was used from the viewpoint of transparency. It is preferable to select two or more rubbery polymers so that the measured refractive index difference is 0.03 or less.

  The weight average particle diameter of the rubbery polymer (a) constituting the graft copolymer (A) in the present invention is not particularly limited, but is 0.1 to 0.5 μm in order to ensure desirable impact strength. In particular, the range of 0.15 to 0.4 μm is preferable. By setting the weight average particle diameter of the rubbery polymer in the range of 0.1 to 0.5 μm, both impact resistance and transparency can be achieved.

  The aromatic vinyl monomer (b) in the present invention is not particularly limited, and specific examples include styrene, α-methylstyrene, orthomethylstyrene, paramethylstyrene, para-t-butylstyrene and the like. Of these, one or more of them can be used. Of these, styrene and α-methylstyrene are preferable, and styrene is particularly preferable.

  There is no restriction | limiting in particular in the vinyl cyanide monomer (c) in this invention, As an example, acrylonitrile or methacrylonitrile etc. are mentioned, These can use 1 type (s) or 2 or more types. Of these, the use of acrylonitrile is preferred in terms of impact resistance.

  The unsaturated carboxylic acid alkyl ester monomer (d) in the present invention is not particularly limited, but acrylic acid esters and / or methacrylic acid esters having an alkyl group having 1 to 6 carbon atoms or substituted alkyl are preferred. . Specific examples of the unsaturated carboxylic acid alkyl ester monomer (d) include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and n-butyl (meth) acrylate. T-butyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, chloromethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 2- (meth) acrylic acid 2- Hydroxyethyl, 3-hydroxypropyl (meth) acrylate, 2,3,4,5,6-pentahydroxyl (meth) acrylate or 2,3,4,5-tetrahydroxypentyl (meth) acrylate, etc. Among them, methyl methacrylate is most preferably used. These can be used alone or in combination of two or more thereof.

  Further, the other vinyl copolymer (e) in the present invention is not particularly limited, but specific examples include (meth) acrylic acid, glycidyl (meth) acrylate, glycidyl itaconate, allyl glycidyl ether, styrene- p-glycidyl ether, p-glycidyl styrene, maleic acid, maleic anhydride, maleic acid monoethyl ester, itaconic acid, itaconic anhydride, phthalic acid, N-methylmaleimide, N-ethylmaleimide, N-cyclohexylmaleimide, N- Phenylmaleimide, acrylamide, methacrylamide, N-methylacrylamide, butoxymethylacrylamide, N-propylmethacrylamide, aminoethyl acrylate, propylaminoethyl acrylate, dimethylaminoethyl methacrylate, ethyl methacrylate Nopropyl, phenylaminoethyl methacrylate, N-vinyldiethylamine, N-acetylvinylamine, allylamine, methallylamine, N-methylallylamine, p-aminostyrene, and the like may be used alone or in combination of two or more. be able to.

  The content of the rubbery polymer (a) contained in the graft copolymer (A) in the present invention is 10 to 80% by weight, preferably 20 to 70% by weight, more preferably 30 to 60% by weight, still more preferably. Is 35 to 55% by weight.

  Moreover, as a preferable ratio of the monomer mixture used for the graft copolymer (A) and the vinyl copolymer (B), the aromatic vinyl monomer (b) is more preferably 9 to 49% by weight. Is 17-37% by weight. Further, the vinyl cyanide monomer (c) is 1 to 30% by weight, more preferably 3 to 20% by weight. The unsaturated carboxylic acid alkyl ester monomer (d) is 50 to 90% by weight, more preferably 60 to 80% by weight. The other vinyl monomer (e) copolymerizable with these is preferably 30% by weight or less. By using at these ratios, good transparency, impact resistance and molding processability can be obtained.

  The thermoplastic resin composition of the present invention is obtained by blending a specific polyorganosiloxane oil (C).

  The polyorganosiloxane oil (C) in the present invention preferably has a refractive index in the range of 1.48 to 1.55, more preferably 1.49 to 1.54, and still more preferably 1.50. ˜1.53 range. If the refractive index is out of the range of the present invention, the transparency of the thermoplastic resin composition may be impaired.

  Although there is no restriction | limiting in particular in polyorganosiloxane oil (C), A methylphenyl silicone oil is suitable.

  When methylphenyl silicone oil is used as the polyorganosiloxane oil (C), the viscosity at 25 ° C. is preferably 20 to 1,000 cSt, and more preferably 30 to 900 cSt. When the viscosity of the methylphenyl silicone oil is below the range of the present invention, it volatilizes from the vacuum vent during melt kneading with the thermoplastic resin, it is difficult to obtain a sufficient effect, and when the viscosity exceeds the range, it is difficult to handle and productivity Decreases.

  The present invention reduces the blending amount of the rubbery polymer (a) in the thermoplastic resin composition to an amount necessary for the development of scratch resistance, and as a result, the impact resistance, which decreases as a specific reduced viscosity, is reduced. This was realized by using a vinyl copolymer (B) having a specific amount of polyorganosiloxane oil (C) and holding it.

  The blending amount P of the rubber polymer (a) is in the range of 2.5 to 11.5% by weight in the total amount of the graft copolymer (A) and the vinyl copolymer (B), preferably 3 0.5 to 10.5% by weight, more preferably 4 to 10% by weight. When the blending amount P is less than the range of the present invention, the impact resistance is inferior, and when it exceeds the range of the present invention, the surface hardness and the scratch resistance are inferior.

  The reduced viscosity R of the vinyl copolymer (B) is in the range of 0.27 to 0.36 dl / g, preferably 0.28 to 0.35 dl / g, and more preferably 0.29 to 0. 34 dl / g. When the reduced viscosity R is less than the range of the present invention, the impact strength is inferior.

  The blending amount Q (% by weight) of the polyorganosiloxane oil (C) in the present invention is the formula (1) “(12) for the blending amount of the rubbery polymer (a) and the reduced viscosity of the vinyl copolymer (B). −31R) / (2P) ≦ Q ≦ 1.2 ”. “(12-31R) / (2P)” representing the lower limit of Q in the formula (1) is the amount P of the rubbery polymer (a) within the scope of the present invention and the vinyl copolymer (B). After the minimum blending amount of the polyorganosiloxane oil (C) capable of satisfying sufficient impact resistance in the combination of the reduced viscosity R is experimentally determined, the reduced viscosity R of the vinyl copolymer (B) is determined for each reduced viscosity R. Further, it is derived by optimizing the relationship between the blending amount P of the rubber polymer (a) and the blending amount Q of the polyorganosiloxane oil (C). If the blending amount Q of the polyorganosiloxane oil (C) is less than the formula (1), sufficient impact strength cannot be obtained. On the other hand, if the blending amount Q exceeds 1.2% by weight, the transparency of the thermoplastic resin composition may be impaired.

  The method for producing the graft copolymer (A) and the vinyl copolymer (B) in the present invention is not particularly limited, and any method such as bulk polymerization, solution polymerization, suspension polymerization or emulsion polymerization may be used. Good. As the monomer charging method, any of initial batch charging, continuous charging of a part or all of the monomer, or divided charging of part or all of the monomer may be used.

  The thermoplastic resin composition of the present invention includes antioxidants such as hindered phenols, sulfur-containing compounds, and phosphorus-containing organic compounds, as long as the intended impact resistance and scratch resistance are not impaired. Various stabilizers such as heat stabilizers such as phenols and acrylates, UV absorbers such as benzotriazoles, benzophenones, and succinates, light stabilizers such as organic nickels and hindered amines, metal salts of higher fatty acids, higher grades Lubricants such as fatty acid amides, plasticizers such as phthalates and phosphates, various flame retardants such as brominated compounds, phosphates and red phosphorus, flame retardant aids such as antimony trioxide and antimony pentoxide , Metal salts of alkyl carboxylic acids and alkyl sulfonic acids, carbon black, pigments or dyes can also be added, It can be blended reinforcing agents and fillers.

  In order to describe the present invention more specifically, examples are given below, but these examples do not limit the present invention in any way. Unless otherwise specified, “%” indicates wt% and “parts” indicates parts by weight.

  A method for analyzing the resin characteristics of the thermoplastic resin composition used in this example will be described below.

(1) Weight average rubber particle diameter “Rubber Age Vol. 88 p. 484-490 (1960) by E. Schmidt, PH Biddison” sodium alginate method (polybutadiene particles creamed by the concentration of sodium alginate) Utilizing the fact that the diameter is different, the particle diameter of 50% cumulative weight fraction is obtained from the weight ratio of creamed weight and the cumulative weight fraction of sodium alginate concentration).

(2) Graft rate 200 ml of acetone was added to a predetermined amount (m; about 1 g) of the graft copolymer and refluxed in a 70 ° C. water bath for 3 hours. p. m. After centrifuging at (10000 G) for 40 minutes, the insoluble matter was filtered, this insoluble matter was dried under reduced pressure at 60 ° C. for 5 hours, and the weight (n) was measured. The graft ratio was calculated from the following formula. Here, L is the rubber content (% / 100) of the graft copolymer.

    Graft rate (%) = {[(n) − (m) × L] / [(m) × L]} × 100.

(3) Reduced viscosity (ηsp / c) of copolymer (A)
The sample to be measured was a 0.4 g / 100 ml methyl ethyl ketone solution, and ηsp / c was measured at 30 ° C. using an Ubbelohde viscometer.

(4) Reduced viscosity (ηsp / c) of insoluble acetone in the graft copolymer (B)
200 g of acetone was added to 1 g of the graft copolymer sample and refluxed in a 70 ° C. water bath for 3 hours. p. m. After centrifuging at (10000 G) for 40 minutes, the insoluble matter is filtered. The filtrate was concentrated with a rotary evaporator, and the precipitate (acetone soluble component) was dried under reduced pressure at 60 ° C. for 5 hours as a 0.4 g / 100 ml methyl ethyl ketone solution in the same manner as (3), using an Ubbelohde viscometer at 30 ° C. Ηsp / c was measured.

(5) Polymerization conversion rate Unreacted monomer content was measured using a gas chromatograph (GC-14A) manufactured by Shimadzu Corporation. The polymerization rate was calculated by the following formula.

Polymerization rate (% by weight) = [(Amount of charged monomer−Amount of unreacted monomer) / Amount of total monomer]
× 100.

(6) Refractive index of acetone-soluble components of copolymer (A), rubbery polymer (b) and thermoplastic resin A small amount of 1-bromonaphthalene is dropped on the sample, and the following conditions are used using an Abbe refractometer The refractive index was measured.

    Light source: sodium lamp D line, measurement temperature: 20 ° C.

(7) Refractive index of acetone-insoluble matter in graft copolymer (B) Using the precipitate after drying under reduced pressure obtained by the same operation as in (4) above, the refractive index is measured in the same manner as in (5) above. did.

(8) Total light transmittance The pellets of the thermoplastic resin composition dried for 3 hours in an 80 ° C. hot air dryer were filled in an IS50A molding machine manufactured by Toshiba Corporation set at a cylinder temperature of 250 ° C. and immediately molded. The haze value [%] of the square plate molded product (thickness 3 mm) was measured using a direct reading haze meter manufactured by Toyo Seiki Co., Ltd.

(9) Pencil hardness Specimens obtained by filling the pellets of a thermoplastic resin composition dried in an 80 ° C. hot air dryer for 3 hours into a Promat molding machine manufactured by Sumitomo Co., Ltd. set at a cylinder temperature of 230 ° C. ISO 3167 Type A (multipurpose test piece) was measured according to JIS K5400.

(10) Scratch resistance test A test piece molded under the same conditions as in the above (9) was tested with an automatic friction / wear tester DFPM-SS type manufactured by Kyowa Interface Chemical Co., Ltd., test load: 500 g, mating material: Pure Leaf M-210, Environmental conditions: Measured at 23 ° C., 50% RH, stroke: 40 mm, frequency: 20 times. The scratch resistance was visually checked for the scratches after the test, and was ranked in five stages according to the number of scratches.

I: 30 or more, II: 20-29, III: 11-19,
IV: 4-10, V: 0-3.

(11) Charpy impact strength A test piece molded under the same conditions as in (9) above was measured according to ISO-179 (23 ° C., with 4 mm thickness V notch). The larger this value, the better the impact resistance.

(12) Melt flow rate The pellets of the thermoplastic resin composition dried in an 80 ° C hot air dryer for 3 hours were measured under the conditions of 220 ° C and 98N according to ISO-1133. The larger this value, the higher the fluidity and the better the moldability.

[Reference Example 1 Production of Graft Copolymer (A-1)]
Polybutadiene latex (rubber particle diameter 0.3 μm, gel content 85%) 50 parts (solid content conversion), pure water 200 parts, sodium formaldehyde sulfoxylate 0.4 parts, ethylenediaminetetraacetate sodium 0.1 parts, sulfuric acid Ferrous iron (0.01 parts) and sodium phosphate 0.1 parts were charged into a reaction vessel, and after nitrogen substitution, the temperature was adjusted to 65 ° C., with stirring, 11.5 parts of styrene, 4.0 parts of acrylonitrile, 34 parts of methyl methacrylate. A mixture of 0.5 part and 0.3 part of n-dodecyl mercaptan was continuously added dropwise over 4 hours. At the same time, 0.25 parts of cumene hydroperoxide, 2.5 parts of sodium laurate as an emulsifier and 25 parts of pure water were continuously added dropwise over 5 hours, and after completion of the addition, the mixture was further maintained for 1 hour for polymerization. Ended. The finished latex was coagulated with 1.5% sulfuric acid, then neutralized with sodium hydroxide, washed, centrifuged and dried to obtain a powdered graft copolymer. The reduced viscosity of the graft component of the obtained graft copolymer (A) was 0.30 dl / g, the graft ratio was 47% by weight, and the refractive index was 1.516.

[Reference Example 2 Production of Vinyl Copolymer (B-1)]
A solution prepared by dissolving 0.05 part of methyl methacrylate / acrylamide copolymer (described in Japanese Patent Publication No. 45-24151) in 165 parts of pure water in a 20 liter autoclave was stirred at 400 rpm, and the system was filled with nitrogen. Replaced with gas. Next, a mixed solution of 5.0 parts of acrylonitrile, 25 parts of styrene, 70 parts of methyl methacrylate, 0.4 part of azobisisobutyronitrile and 0.30 part of t-dodecyl mercaptan was added while stirring the reaction system. The copolymerization reaction was started at 60 ° C. The temperature was further raised to 65 ° C over 15 minutes, and then raised to 100 ° C over 50 minutes. After reaching the temperature for 30 minutes at 100 ° C., cooling, polymer separation, washing, and drying were performed to obtain a bead copolymer that enables the present invention. The reduced viscosity of the obtained vinyl copolymer (B-1) was 0.32 dl / g, and the refractive index was 1.516.

[Reference Example 3 Production of Vinyl Copolymer (B-2)]
Among the conditions of the above B-1, except that the amount of t-dodecyl mercaptan in the mixed solution was 0.18 part, polymerization was carried out in the same manner as in B-1, and the bead-like copolymerization enabling the present invention Coalescence was obtained. The reduced viscosity of the obtained vinyl copolymer (B-2) was 0.35 dl / g, and the refractive index was 1.518.

[Reference Example 4 Production of Vinyl Copolymer (B-3)]
Among the above conditions of B-1, except that the amount of t-dodecyl mercaptan in the mixed solution was 0.40 part, the polymerization was performed in the same manner as in B-1, and the bead-like copolymerization enabling the present invention Coalescence was obtained. The reduced viscosity of the obtained vinyl copolymer (B-3) was 0.28 dl / g, and the refractive index was 1.518.

[Reference Example 5 Production of Vinyl Copolymer (B-4)]
The bead copolymer used for the comparative example is polymerized in the same manner as in B-1, except that the amount of t-dodecyl mercaptan in the mixed solution is 0.45 part among the above conditions of B-1. Got. The reduced viscosity of the obtained vinyl copolymer (B-4) was 0.25 dl / g, and the refractive index was 1.516.

[Reference Example 6 Production of Vinyl Copolymer (B-5)]
Among the conditions of B-1, the amount of azobisisobutyronitrile in the mixed solution was 0.25 part, the amount of t-dodecyl mercaptan was 0.15 part, and the copolymerization reaction was started at 60 ° C. . The temperature was further raised to 65 ° C over 15 minutes, and then raised to 100 ° C over 30 minutes. 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 copolymer used in the comparative example. The reduced viscosity of the obtained vinyl copolymer (B-5) was 0.39 dl / g, and the refractive index was 1.520.

[Reference Example 7 Production of Vinyl Copolymer (B-6)]
Among the conditions of the above B-1, except that the amount of acrylonitrile in the mixed solution is 27 parts, the amount of styrene is 73 parts, and methyl methacrylate is not added, polymerization is performed in the same manner as in B-1, A bead copolymer used in the examples was obtained. The resulting vinyl copolymer (B-6) had a reduced viscosity of 0.55 dl / g and a refractive index of 1.558.

[Reference Example 8 Polyorganosiloxane Oil (C-1)]
“KF54” methyl phenyl silicone oil manufactured by Shin-Etsu Silicone Co., Ltd., refractive index = 1.505 was used.

[Reference Example 9 Polyorganosiloxane Oil (C-2)]
“SH702” methyl phenyl silicone oil manufactured by Toray Dow Corning Co., Ltd., refractive index = 1.52 was used.

[Reference Example 10 Polyorganosiloxane Oil (C-3)]
“SH200” dimethyl silicone oil manufactured by Toray Dow Corning Co., Ltd., refractive index = 1.40 was used. The refractive index of (C-3) is out of the range of the present invention.

[Examples 1 to 6]
Graft copolymer (A) produced in the above reference example, vinyl copolymer (B-1), (B-2) or (B-3), polyorganosiloxane (C-1) or (C -2) was kneaded with a Henschel mixer as a blending ratio shown in Table 1, and then extruded into a gut shape at an extrusion temperature of 250 ° C. with a 40 mmφ extruder. Next, using the obtained pellets, injection molding was performed at a molding temperature of 230 ° C. and a mold temperature of 40 ° C. to prepare test pieces for evaluation. Table 1 shows the results of measuring physical properties of these test pieces.

  As is apparent from the results of Examples 1 to 6, the thermoplastic resin composition of the present invention has transparency (total light transmittance), pencil hardness, scratch resistance, Charpy impact strength, and moldability (melt flow rate). Everything was excellent.

[Comparative Examples 1 to 11]
The graft copolymer (A) produced in the above reference example and the vinyl copolymer (B-1), (B-2), (B-3), (B-4), (B-5) or After kneading (B-6) and polyorganosiloxane oil (C-1) or (C-3) with a Henschel mixer as the blending ratio shown in Table 2 or Table 3, the extrusion temperature is 250 ° C. with a 40 mmφ extruder. Was extruded into a gut shape and pelletized. Next, using the obtained pellets, injection molding was performed at a molding temperature of 230 ° C. and a mold temperature of 40 ° C. to prepare test pieces for evaluation. Tables 2 and 3 show the results of measuring physical properties of these test pieces.

  In Comparative Example 1, the reduced viscosity of the vinyl copolymer (B-4) was lower than the range of the present invention, and the impact strength was inferior.

  In Comparative Example 2, the reduced viscosity of the vinyl copolymer (B-5) was higher than the range of the present invention, and the melt flow rate was low, so the moldability was poor.

  Moreover, the comparative example 3 had more compounding quantities of polyorganosiloxane oil (C-1) than the range of this invention, and transparency was inferior.

  Further, Comparative Example 4 has a larger amount of the rubber polymer (a) in the thermoplastic resin than Example 5, and is out of the scope of the present invention. Therefore, transparency and impact resistance are satisfied. Pencil hardness and scratch resistance were inferior.

  In Comparative Example 5, the blending amount of the rubber polymer (a) in the thermoplastic resin was less than the range of the present invention, and the impact strength was inferior.

  Moreover, since the comparative example 6 did not contain polyorganosiloxane oil (C), the impact strength was inferior.

  Moreover, since the refractive index of the polyorganosiloxane oil (C-3) was smaller than the range of this invention, the comparative example 7 was inferior in transparency.

  Moreover, since Comparative Example 8 did not contain methyl methacrylate in the vinyl copolymer (B-6), all of transparency, pencil hardness, scratch resistance, and melt flow rate were inferior.

  Moreover, since the comparative example 9 did not contain the graft copolymer (A), the impact strength was inferior.

  In Comparative Example 10, the amount Q of the polyorganosiloxane oil (C-1) is obtained from the relational expression between the amount of the rubber polymer (a) and the reduced viscosity R of the vinyl copolymer (B). The impact strength was inferior.

  In Comparative Example 11, the blending amount of the rubber polymer (a) in the thermoplastic resin is larger than the range of the present invention, and transparency and impact resistance are satisfied, but pencil hardness, scratch resistance and melt The flow rate was inferior.

That is, the thermoplastic resin composition of the comparative example could not satisfy all of transparency, pencil hardness, scratch resistance, surface hardness, impact strength, and moldability.

Claims (6)

Graft copolymer containing rubbery polymer (a), aromatic vinyl monomer (b), vinyl cyanide monomer (c) and unsaturated carboxylic acid alkyl ester monomer (d) A vinyl copolymer (B) containing (A), an aromatic vinyl monomer (b), a vinyl cyanide monomer (c) and an unsaturated carboxylic acid alkyl ester monomer (d) ) Is a thermoplastic resin composition obtained by blending polyorganosiloxane oil (C), and a rubber polymer (A) in the total amount of graft copolymer (A) and vinyl copolymer (B). The blending amount P of a) is in the range of 2.5 to 11.5% by weight, the reduced viscosity R of the vinyl copolymer (B) is in the range of 0.27 to 0.36 dl / g, and The amount Q (wt%) of the organosiloxane oil (C) is
Formula (1): (12-31R) / (2P) ≦ Q ≦ 1.2
And the total light transmittance at a thickness of 3 mm measured at 23 ° C. is 80% or more.   The monomer mixture constituting the graft copolymer (A) is a rubbery polymer (a) 10 to 80% by weight, an aromatic vinyl monomer (b) 9 to 49% by weight, a vinyl cyanide monomer 1 to 30% by weight of monomer (c), 50 to 90% by weight of unsaturated carboxylic acid alkyl ester monomer (d) and 0 to 30% by weight of other vinyl monomers copolymerizable with these (e) The transparent thermoplastic resin composition according to claim 1, comprising:   The composition constituting the vinyl copolymer (B) is 9 to 49% by weight of the aromatic vinyl monomer (b), 1 to 30% by weight of the vinyl cyanide monomer (c), and an unsaturated alkyl carboxylate. It consists of 50 to 90% by weight of the ester monomer (d) and 0 to 30% by weight of another vinyl monomer (e) copolymerizable therewith. The transparent thermoplastic resin composition described in 1.   The transparent thermoplastic resin composition according to any one of claims 1 to 3, wherein the polyorganosiloxane oil (C) has a refractive index in the range of 1.48 to 1.55.   The transparent thermoplastic resin composition according to any one of claims 1 to 4, wherein the polyorganosiloxane oil (C) is a methylphenyl silicone oil having a viscosity of 20 to 1,000 cSt at 25 ° C. The molded article which consists of a transparent thermoplastic resin composition of any one of Claims 1-5.