JP2008214469A - Thermoplastic resin composition and molding thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoplastic resin composition which can be molded into a molding with excellent appearance and to provide a molding with excellent appearance comprising the thermoplastic resin composition. <P>SOLUTION: The thermoplastic resin composition is a resin composition which comprises 10-50 pts.wt. rubber-containing graft copolymer (I) prepared by grafting a vinyl monomer or a vinyl monomer mixture onto a rubbery polymer, 5-40 pts.wt. vinyl copolymer (II) prepared by copolymerizing at least two vinyl monomers, 10-60 pts.wt. aliphatic polyester (III), 5-50 pts.wt. (co)polymer (IV) of an alkyl ester (d) of an unsaturated carboxylic acid and contains 2-10 pts.wt. titanium dioxide (V), (I)+(II)+(III)+(IV)=100 pts.wt., wherein the resin composition contains not less than 20 wt.% alkyl ester (d) of an unsaturated carboxylic acid and satisfies the formula: 0.6≤(d) content (wt.%)/(III) content (wt.%). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a thermoplastic resin composition that gives a molded article having an excellent appearance when molded, and a molded article using the thermoplastic resin composition.

  Recently, an increase in the concentration of carbon dioxide in the atmosphere has been pointed out as a cause of global warming, and regulation of carbon dioxide emissions on a global scale has become necessary. The sources of carbon dioxide emission include respiration of organisms and spoilage and fermentation by bacteria, but a large part is generated by combustion, and the main cause of the current phenomenon of rising carbon dioxide concentration is wasting human oil resources This is due to the economic activity.

  In recent years, the use of plant resources that absorb and fix carbon dioxide has attracted attention as carbon neutral, and in addition to carbon dioxide fixation by plants, alternatives to petroleum resources are being studied.

  Also in plastics, this biomass is utilized, and the reduction of the amount of petroleum raw materials used and the reduction of carbon dioxide emission are attracting attention, and plant-derived plastics are attracting attention.

  As such plant-derived plastics, aliphatic polyesters typified by polylactic acid resins have been studied, but these resins are inferior in mechanical strength and heat resistance compared to existing petroleum-based plastics. There has been a study on strength improvement.

For example, a method of adding a rubber-containing multilayer structure polymer containing an unsaturated carboxylic acid alkyl ester-based unit in the outermost layer to an aliphatic polyester has been proposed (see Patent Document 1). A method of adding a rubber reinforced resin to a polylactic acid resin has also been proposed (see Patent Document 2 and Patent Document 3). However, in these methods, a weld line and a flow mark are remarkably generated in the appearance of the molded article, and a molded article having a good appearance is not obtained.
JP 2003-286396 A (Claim 1) JP 2006-137908 A (Claim 1) Japanese Patent Laying-Open No. 2006-161024 (Claim 1)

  Accordingly, an object of the present invention is to eliminate the drawbacks of the prior art described above, and to provide a thermoplastic resin composition that gives a molded article having an excellent appearance when molded, and an appearance made of the thermoplastic resin composition. It is to provide a molded article.

  As a result of intensive studies on the achievement of the above object, the present inventors have identified the rubber-containing graft copolymer, vinyl copolymer, aliphatic polyester, and unsaturated carboxylic acid alkyl ester (co) polymer. By adding an amount of titanium oxide to a specific unsaturated carboxylic acid alkyl ester content, the inventors have found a thermoplastic resin composition capable of obtaining a molded article having an excellent appearance, and have arrived at the present invention.

The thermoplastic resin composition of the present invention is a rubber-containing graft copolymer (I) obtained by graft copolymerizing a vinyl monomer or a vinyl monomer mixture with a rubber polymer (a) in an amount of 10 to 50 weights. 5 to 40 parts by weight of a vinyl copolymer (II) obtained by copolymerizing at least two kinds of vinyl monomers, 10 to 60 parts by weight of an aliphatic polyester (III), and an unsaturated carboxylic acid alkyl ester (D) 5 to 50 parts by weight of the (co) polymer (IV), and with respect to (I) + (II) + (III) + (IV) = 100 parts by weight, titanium oxide ( V) 2 to 10 parts by weight of a resin composition comprising 20% by weight or more of unsaturated carboxylic acid alkyl ester (d) in the resin composition and satisfying the following formula: It is a composition.
0.6 ≦ Unsaturated carboxylic acid alkyl ester content (% by weight) / aliphatic polyester content (% by weight)
According to a preferred embodiment of the thermoplastic resin composition of the present invention, the rubber-containing graft copolymer (I) comprises a rubbery polymer (a), an aromatic vinyl monomer (b), and vinyl cyanide. A vinyl monomer or vinyl selected from the group consisting of a monomer (c), an unsaturated carboxylic acid alkyl ester monomer (d), and another copolymerizable vinyl monomer (e) A rubber-containing graft copolymer obtained by graft copolymerizing a monomer mixture.

  According to a preferred embodiment of the thermoplastic resin composition of the present invention, the rubber-containing graft copolymer (I) is added to the rubbery polymer (a) with an aromatic vinyl monomer (b) of 10 to 80 wt. %, 0 to 20% by weight of vinyl cyanide monomer (c), 20 to 90% by weight of unsaturated carboxylic acid alkyl ester monomer (d) and other vinyl monomers copolymerizable (e ) A rubber-containing graft copolymer obtained by graft-copolymerizing 0 to 60% by weight.

  According to a preferred embodiment of the thermoplastic resin composition of the present invention, the vinyl copolymer (II) comprises an aromatic vinyl monomer (b), a vinyl cyanide monomer (c), A vinyl copolymer obtained by copolymerizing a vinyl monomer selected from the group consisting of a saturated carboxylic acid alkyl ester (d) and another copolymerizable vinyl monomer (e).

  According to a preferred embodiment of the thermoplastic resin composition of the present invention, the vinyl copolymer (II) comprises 20 to 85% by weight of an aromatic vinyl monomer (b), a vinyl cyanide compound (c). 1-55% by weight, unsaturated carboxylic acid alkyl ester (d) 0-79% by weight and other copolymerizable vinyl monomer (e) 0-50% by weight vinyl copolymer It is.

  According to a preferred embodiment of the thermoplastic resin composition of the present invention, the aliphatic polyester (III) is polylactic acid, and the titanium oxide (V) is rutile titanium oxide.

  The thermoplastic resin composition of the present invention can be molded into a molded product.

  ADVANTAGE OF THE INVENTION According to this invention, the thermoplastic resin composition which does not generate | occur | produce a weld line or a flow mark in the external appearance of the shape | molded molded product, and can be set as the molded product excellent in the external appearance by shaping | molding is obtained. In particular, by using the thermoplastic resin composition, a molded product excellent in appearance suitable for various uses such as OA equipment, home appliances, and general goods can be obtained.

  Hereinafter, the thermoplastic resin composition of the present invention will be specifically described.

  The thermoplastic resin composition of the present invention comprises a rubber-containing graft copolymer (I), a vinyl copolymer (II), an aliphatic polyester (III), an unsaturated carboxylic acid alkyl ester (d) (co) polymer. It contains (IV) and titanium oxide (V).

  The rubber-containing graft copolymer (I) used in the present invention is obtained by graft copolymerizing a vinyl monomer or a vinyl monomer mixture with a rubber polymer (a).

  Examples of the rubbery polymer (a) constituting the rubber-containing graft copolymer (I) used in the present invention include, for example, diene rubber, acrylic rubber, and ethylene rubber. Specifically, Polybutadiene, poly (butadiene-styrene), poly (butadiene-acrylonitrile), polyisoprene, poly (butadiene-butyl acrylate), poly (butadiene-methyl acrylate), poly (butadiene-methyl methacrylate), poly (butadiene- Ethyl acrylate), ethylene-propylene rubber, ethylene-propylene-diene rubber, poly (ethylene-isobutylene), poly (ethylene-methyl acrylate), poly (ethylene-ethyl acrylate) and the like. These rubbery polymers (a) are used in one kind or a mixture of two or more kinds. Among them, polybutadiene and styrene-butadiene copolymer rubber are particularly preferably used from the viewpoint of impact resistance improvement effect.

  The weight average rubber particle diameter of the rubber polymer (a) is preferably in the range of 0.1 to 1.5 μm, more preferably in terms of impact resistance, molding processability, fluidity and appearance. It is in the range of 0.15 to 1.2 μm.

  The rubbery polymer (a) content in the rubber-containing graft copolymer (I) is preferably 5 to 80 parts by weight, more preferably 10 to 70 parts by weight from the balance between toughness and rigidity. More preferably, it is 40-70 weight part.

  As the vinyl monomer of the graft component constituting the rubber-containing graft copolymer (I) used in the present invention, an aromatic vinyl monomer (b), a vinyl cyanide monomer (c), A vinyl monomer selected from the group consisting of an unsaturated carboxylic acid alkyl ester monomer (d) and another copolymerizable vinyl monomer (e) is preferred.

  The graft component is more preferably an aromatic vinyl monomer (b) 10 to 80% by weight, vinyl cyanide monomer (c) 0 to 20% by weight, unsaturated carboxylic acid in terms of impact resistance. It is composed of 20 to 90% by weight of an alkyl ester monomer (d) and 0 to 60% by weight of another copolymerizable vinyl monomer (e), more preferably an aromatic vinyl monomer. (B) 15 to 35% by weight, vinyl cyanide monomer (c) 0 to 10% by weight, unsaturated carboxylic acid alkyl ester monomer (d) 60 to 80% by weight and other copolymerizable monomers The vinyl monomer (e) consists of 0 to 40% by weight.

  Examples of the aromatic vinyl monomer (b) include styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, t-butylstyrene, o-ethylstyrene, o-chlorostyrene, and o, p. -Dichlorostyrene and the like can be mentioned, and styrene and α-methylstyrene are particularly preferably used. These can be used alone or in a mixture of two or more.

  Examples of the vinyl cyanide monomer (c) include acrylonitrile, methacrylonitrile, ethacrylonitrile and the like, and acrylonitrile is particularly preferably used. These can be used alone or in a mixture of two or more.

  As the unsaturated carboxylic acid alkyl ester monomer (d), for example, acrylic acid esters and / or methacrylic acid esters having an alkyl group having 1 to 6 carbon atoms or a substituted alkyl group are suitable. One kind or a mixture of two or more kinds can be used. 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 and 2-chloroethyl (meth) acrylate, among others. Methyl methacrylate is preferably used.

  Specific examples of the other copolymerizable monomer (e) include maleimide compounds such as N-methylmaleimide, N-cyclohexylmaleimide and N-phenylmaleimide, and unsaturated dicarboxylic acids such as maleic acid. Examples thereof include vinyl compounds typified by unsaturated dicarboxylic acid anhydrides such as acid and maleic anhydride, and unsaturated amide compounds such as acrylamide. These can be used alone or in a mixture of two or more.

  The graft ratio of the vinyl monomer in the rubber-containing graft copolymer (I) is preferably 15 to 100% by weight, and more preferably 20 to 70% by weight. If the graft ratio is outside the range of 15 to 100% by weight, the mechanical properties may be deteriorated.

  The method for producing the rubber-containing graft copolymer (I) may be any polymerization method such as emulsion polymerization, suspension polymerization, bulk polymerization, and solution polymerization, and is not particularly limited. Also, there is no particular limitation on the charging method of each monomer, and initial or batch charging, or part or all of the charged monomer is charged continuously or divided in order to suppress the generation of the composition distribution of the copolymer. However, polymerization may be performed.

  The thermoplastic resin composition of the present invention needs to contain 10 to 50 parts by weight of the rubber-containing graft copolymer (I). This is because if the content of the rubber-containing graft copolymer (I) is less than 10 parts by weight, the toughness is inferior, and if it exceeds 50 parts by weight, the rigidity is inferior. The content of the rubber-containing graft copolymer (I) is preferably 15 to 50 parts by weight, more preferably 20 to 45 parts by weight.

  The vinyl copolymer (II) used in the present invention is required to copolymerize at least two kinds of vinyl monomers. Examples of vinyl monomers include aromatic vinyl monomers (b), vinyl cyanide monomers (c), unsaturated carboxylic acid alkyl ester monomers (d), and other copolymerizable monomers. A vinyl monomer selected from the group consisting of vinyl monomers (e) is preferred.

  The vinyl copolymer (II) is more preferably an aromatic vinyl monomer (b) 20 to 85% by weight, a vinyl cyanide monomer (c) 1 to 55% by weight, an unsaturated carboxylic acid. It is obtained by copolymerizing 0 to 79% by weight of an alkyl ester monomer (d) and 0 to 50% by weight of another copolymerizable vinyl monomer (e).

  Here, each of the above-mentioned monomers (b), (c), (d) and (e) is each of the monomers (b) described in the above-mentioned rubber-containing graft copolymer (I). , (C), (d) and (e) can be used.

  The viscosity of the vinyl copolymer (II) is preferably 0.30 to 2.00 dl / g in reduced viscosity in methyl ethyl ketone, more preferably 0.32 to 1.8 dl / g. g, more preferably 0.33 to 1.50 dl / g.

  As a method for producing the vinyl copolymer (II), any polymerization method such as emulsion polymerization, suspension polymerization, bulk polymerization, and solution polymerization may be used, and it is not particularly limited. Also, there is no particular limitation on the charging method of each monomer, and initial or batch charging, or part or all of the charged monomer is charged continuously or divided in order to suppress the generation of the composition distribution of the copolymer. However, polymerization may be performed.

  The thermoplastic resin composition of the present invention needs to contain 5 to 40 parts by weight of the vinyl copolymer (II). This is because if the content of the vinyl copolymer (II) is less than 5 parts by weight, the rigidity is inferior, and if it exceeds 40 parts by weight, the impact resistance is inferior. The content of the vinyl copolymer (II) is preferably 10 to 40 parts by weight, more preferably 10 to 35 parts by weight.

  Examples of the aliphatic polyester (III) used in the present invention include polymers containing aliphatic hydroxycarboxylic acids as main constituents, and polymers containing aliphatic polycarboxylic acids and aliphatic polyhydric alcohols as main constituents. Examples include coalescence. Examples of the polymer containing aliphatic hydroxycarboxylic acid as a main constituent include, for example, polyglycolic acid, polylactic acid, poly-3-hydroxybutyric acid, poly-4-hydroxybutyric acid, poly-4-hydroxyvaleric acid, and poly-3-hydroxyhexanoic acid. And polylactone. Examples of the polymer mainly comprising an aliphatic polycarboxylic acid and an aliphatic polyhydric alcohol include polyethylene adipate, polyethylene succinate, polybutylene adipate, polybutylene succinate, and copolymers thereof. Can be mentioned. These aliphatic polyesters can be used alone or in a mixture of two or more.

  Among these aliphatic polyesters, a polymer mainly containing an aliphatic hydroxycarboxylic acid is preferable, and polylactic acid is particularly preferable.

  Polylactic acid is a polymer mainly composed of L-lactic acid and / or D-lactic acid, but may contain other copolymer components other than lactic acid. The monomer units as other copolymerization components include ethylene glycol, polypropylene glycol, butanediol, heptanediol, hexanediol, octanediol, nonanediol, decanediol, 1,4-cyclohexanediol, neopentyl glycol, glycerin, and pentane. Glycol compounds such as erythritol, bisphenol A, polyethylene glycol, polypropylene glycol and polytetramethylene glycol, oxalic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, malonic acid, glutaric acid, cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid Acid, phthalic acid, naphthalenedicarboxylic acid, bis (p-carboxyphenyl) methane, anthracene dicarboxylic acid, 4,4'-diphenyl Dicarboxylic acids such as terdicarboxylic acid, 5-sodiumsulfoisophthalic acid and 5-tetrabutylphosphonium isophthalic acid, glycolic acid, hydroxypropionic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid and hydroxybenzoic acid, and Examples include lactones such as caprolactone, valerolactone, propiolactone, undecalactone, and 1,5-oxepan-2-one.

  Such other copolymer component is preferably contained in a content of generally 0 to 30 mol%, more preferably 0 to 10 mol%, in all monomer components.

  In order to obtain high heat resistance by using polylactic acid, it is preferable that the engineering purity of the lactic acid component is high, and it is preferable that 80 mol% or more of L-form or D-form is contained in the total lactic acid component. Is preferably contained in an amount of 90 mol% or more, and particularly preferably 95 mol% or more.

  As a method for producing the aliphatic polyester (III), a known polymerization method can be used. In particular, for polylactic acid, a direct polymerization method from lactic acid or a ring-opening polymerization method via lactide can be employed.

  The molecular weight and molecular weight distribution of the aliphatic polyester (III) are only required to be substantially moldable, and the weight average molecular weight is preferably 10,000 or more, more preferably 20,000 or more, particularly preferably. Is over 40,000. The weight average quantity here is a weight average quantity in terms of polymethyl methacrylate (PMMA) measured by gel permeation chromatography (GPC) using hexafluoroisopropanol as a solvent. Further, the melting point of the aliphatic polyester (III) is preferably 90 ° C. or higher, more preferably 150 ° C. or higher.

  In the thermoplastic resin composition of the present invention, the aliphatic polyester (III) needs to be 10 to 60 parts by weight. This is because if the content of the aliphatic polyester (III) is less than 10 parts by weight, the effect of reducing the petrochemical raw material as biomass is small, and if the content exceeds 60 parts by weight, the heat resistance is poor. The content of the aliphatic polyester (III) is preferably 20 to 60 parts by weight, more preferably 20 to 50 parts by weight.

  The thermoplastic resin composition of the present invention further requires at least one unsaturated carboxylic acid alkyl ester (d) (co) polymer (IV). Here, the (co) polymer refers to a polymer, a copolymer, or a mixture thereof.

  As the unsaturated carboxylic acid alkyl ester (d), the same monomer as the unsaturated carboxylic acid alkyl ester (d) described in the rubber-containing graft copolymer (I) can be used. In the thermoplastic resin composition of the present invention, the content of the unsaturated carboxylic acid alkyl ester (d) (co) polymer (IV) is 5 to 50 parts by weight. This is because the content is large and inferior in impact resistance within and outside this range. The content is preferably 10 to 45 parts by weight, more preferably 10 to 35 parts by weight.

  The unsaturated carboxylic acid alkyl ester (d) (co) polymer (IV) preferably has a reduced viscosity in methyl ethyl ketone of 0.30 to 2.00 dl / g, more preferably 0.000. It is 32-1.8 dl / g, More preferably, it is 0.33-1.50 dl / g.

  As commercial products of unsaturated carboxylic acid alkyl ester (d) (co) polymer (IV), polymethyl methacrylate resin “Acrypet G” (registered trademark) manufactured by Kuraray Co., Ltd. and “Sumipec” manufactured by Sumitomo Chemical Co., Ltd. ( Registered trademark).

  The production method of the unsaturated carboxylic acid alkyl ester (d) (co) polymer (IV) may be any polymerization method such as emulsion polymerization, suspension polymerization, bulk polymerization, and solution polymerization, and is not particularly limited. . Also, there is no particular limitation on the charging method of each monomer, and initial or batch charging, or part or all of the charged monomer is charged continuously or divided in order to suppress the generation of the composition distribution of the copolymer. However, polymerization may be performed.

  The thermoplastic resin composition of the present invention needs to contain titanium oxide (V). As titanium oxide (V), those generally used as a colorant are used, and rutile type titanium oxide is particularly preferably used. The primary particle size is preferably 0.1 to 1 μm.

  Examples of commercially available titanium oxide (V) include trade names R980 and A220 manufactured by Ishihara Sangyo Co., Ltd. and trade names R-11P and SA-1 manufactured by Sakai Chemical Industry.

  In the thermoplastic resin composition of the present invention, titanium oxide (V) is added to 100 parts by weight of the total of the rubber-containing graft copolymer (I), the vinyl copolymer (II) and the aliphatic polyester (III). It is necessary to contain 2 to 10 parts by weight. When the content of titanium oxide (V) is less than 2 parts by weight, appearance defects such as welds and flow marks are observed, and when it exceeds 10 parts by weight, the toughness is significantly reduced.

  The thermoplastic resin composition of the present invention needs to contain 20% by weight or more of unsaturated carboxylic acid alkyl ester (d) in the resin composition. When the content of the unsaturated carboxylic acid alkyl ester (d) is less than 20 parts by weight, appearance defects such as welds and flow marks are observed. The content is preferably 20 to 40% by weight, more preferably 25 to 40% by weight.

The thermoplastic resin composition of the present invention has the following formula: 0.6 ≦ unsaturated carboxylic acid alkyl ester (d) content (% by weight) / aliphatic polyester (III) content (% by weight)
It is necessary to satisfy When the value of the above formula is less than 0.6, appearance defects such as welds and flow marks are observed. The value of the above formula is preferably 0.8 or more, more preferably 0.8 to 2.0. When the value of the above formula exceeds 2.0, the impact resistance tends to be inferior.

  Next, the manufacturing method of the thermoplastic resin composition of this invention is demonstrated. Of rubber-containing graft copolymer (I), vinyl copolymer (II), aliphatic polyester (III), unsaturated carboxylic acid alkyl ester (d) (co) polymer (IV) and titanium oxide (V) About the compounding method of each component, the tumbler mixer, the blender, the Henschel mixer, etc. which are generally used can be used. As for melt kneading, a single screw extruder, a twin screw extruder, a Banbury mixer and the like used for general melt kneading can be used, but a twin screw extruder is preferably used from the viewpoint of dispersibility. The melt kneading temperature is preferably melt kneaded at 150 to 250 ° C. because the aliphatic polyester is easily decomposed at a high temperature.

  The thermoplastic resin composition of the present invention includes polyvinyl chloride, polyolefins such as polyethylene and polypropylene, polyamides such as nylon 6 and nylon 66, polyethylene terephthalate, polybutylene terephthalate, and poly, within the range not impairing the effects of the present invention. Polyester such as cyclohexanedimethyl terephthalate, polycarbonate, various elastomers and the like can be added to improve the performance as a molding resin.

  If necessary, the thermoplastic resin composition of the present invention may be added to a sulfur-containing organic compound-based antioxidant, a phenol-based or acrylate-based heat stabilizer, benzotriazole-based, benzophenone-based, salicylate-based, etc. Various stabilizers such as UV absorbers, light stabilizers such as organic nickel and hindered amines, lubricants such as metal salts of higher fatty acids, higher fatty acid amides, plasticizers such as phthalates and phosphates, poly Halogenated compounds such as bromodiphenyl ether, tetrabromobisphenol-A, brominated epoxy oligomers and brominated polycarbonate oligomers, flame retardants and flame retardants such as phosphorus compounds and antimony trioxide, antistatic agents, titanium oxide, etc. Pigments and dyes can also be added.

  In the thermoplastic resin composition of the present invention, a reinforcing agent or filler such as glass fiber, glass flake, glass bead, carbon fiber and metal fiber may be further added within the range not impairing the effect of the present invention. it can.

  The thermoplastic resin composition obtained as described above is molded by a known method used for molding of present thermoplastic resins such as injection molding, extrusion molding, blow molding, vacuum molding, compression molding, and gas assist molding. There is no particular limitation.

  The thermoplastic resin composition of the present invention makes use of features that are excellent in impact resistance, thermal stability, fluidity, and appearance of molded products, housings for OA equipment, home appliances, etc., their parts, various miscellaneous goods and sheets. Suitable for

  Hereinafter, in order to more specifically explain the thermoplastic resin composition of the present invention, the following examples are given, but these examples do not limit the present invention in any way. Here, unless otherwise specified, “%” means% by weight, and “part” means part by weight. The measurement methods of characteristics and physical properties used in the examples are as follows.

(1) Weight average rubber particle diameter of rubbery polymer Sodium alginate method described in “Rubber Age Vol.88 p.484-490 (1960), by E. Schmidt, PHBiddison”, that is, creaming by the concentration of sodium alginate The particle diameter of 50% cumulative weight fraction was determined from the weight ratio of cream and the cumulative weight fraction of sodium alginate concentration by utilizing the difference in the polybutadiene particle diameter.

(2) Graft ratio of rubber-containing graft copolymer (I) 100 ml of acetone was added to a predetermined amount (m; about 1 g) of rubber-containing graft copolymer (I) that had been vacuum-dried at 80 ° C. for 4 hours. And refluxed in a hot water bath at a temperature of 70 ° C. for 3 hours. p. m. After centrifuging at (10000 G) for 40 minutes, the insoluble matter was filtered, this insoluble matter was vacuum dried at 80 ° C. for 4 hours, and the weight (n) was measured. The graft ratio was calculated from the following formula. Here, L is the rubber content of the rubber-containing graft copolymer.
Graft rate (%) = {[(n) − (m) × L] / [(m) × L]} × 100.

(3) Reduced viscosity ηsp / c
The measurement sample was dissolved in methyl ethyl ketone, and the reduced viscosity ηsp / c was measured at a temperature of 30 ° C. using a Ubbelohde viscometer as a 0.4 g / 100 ml methyl ethyl ketone solution.

(4) Heat resistance of thermoplastic resin composition Measured by ASTM D648 (1988 version, 6.4 mm, 1.82 MPa load).

(5) Flexural modulus of thermoplastic resin composition Measured using Tensilon manufactured by Toyo Seiki Co., Ltd. according to ASTM D790 (1988 version).

(6) Izod Impact Strength Measured by ASTM D256 (1988 version, 23 ° C., with V notch).

(7) Appearance of molded product The thermoplastic resin composition is put into an injection molding machine (PS60, manufactured by Nissei Co., Ltd.), and the square plate is molded using the mold shown in FIG. did. The appearance of the square plate after molding was visually determined. The case where the flow mark and the weld line were conspicuous was marked as x, the case where the flow mark or the weld line was slightly visible was marked as △, and the case where both were not noticeable was marked as ◯. FIG. 1 shows a square plate that forcibly generates welds. By injecting a thermoplastic resin from gates at both ends, the molten resin collides at a right angle at the central portion of the square plate to generate welds.

(8) Comprehensive evaluation Izod impact strength is 150 J / m or more and the appearance of the molded product is ○, and Izod impact strength is 150 J / m or more and the appearance of the molded product is △, and Izod impact strength Of less than 150 J / m or the appearance of the molded article x.

(Reference Example 1) Production of rubber-containing graft copolymer (I) (1) Production of rubber-containing graft copolymer (I-1) In a reactor purged with nitrogen, 120 parts of pure water, 0.5 part of glucose, Charge 0.5 parts of sodium pyrophosphate, 0.005 parts of ferrous sulfate and 50 parts by weight of polybutadiene latex (number average rubber particle size: 0.3 μm), and raise the temperature in the reactor to 65 ° C. while stirring. did. When the internal temperature reached 65 ° C, polymerization was started, and styrene (35 parts by weight), acrylonitrile (15 parts by weight) and a chain transfer agent t-dodecyl mercaptan mixture (0.25 parts) were continuously added over 5 hours. did. At the same time, an aqueous solution comprising a polymerization initiator cumene hydroperoxide (0.2 parts) and potassium oleate (2.5 parts) was continuously added over 7 hours to complete the reaction. To the obtained latex, 1 part by weight of 2,2′-methylenebis (4-methyl-6-tert-butylphenol) was added to 100 parts by weight of latex solids, and the latex was coagulated with sulfuric acid. The mixture was neutralized with sodium hydroxide, washed, filtered, and dried to obtain a powdery rubber-containing graft copolymer (I-1). The graft ratio of this rubber-containing graft copolymer (I-1) was 44%.

(2) Production of rubber-containing graft copolymer (I-2) In a reactor purged with nitrogen, pure water 120 parts, glucose 0.5 parts, sodium pyrophosphate 0.5 parts, ferrous sulfate 0.005 parts And 50 parts by weight of polybutadiene latex (number average rubber particle diameter: 0.3 μm) was charged, and the temperature in the reactor was raised to 65 ° C. while stirring. The polymerization was started when the internal temperature reached 65 ° C., and 35 parts of methyl methacrylate, 12.5 parts of styrene, 2.5 parts of acrylonitrile, and 0.3 part of t-dodecyl mercaptan were continuously added over 5 hours. At the same time, an aqueous solution comprising a polymerization initiator cumene hydroperoxide (0.2 parts) and potassium oleate (2.5 parts) was continuously added over 7 hours to complete the reaction. To the obtained latex, 1 part by weight of 2,2′-methylenebis (4-methyl-6-tert-butylphenol) was added to 100 parts by weight of latex solids, and the latex was coagulated with sulfuric acid. The mixture was neutralized with sodium hydroxide, washed, filtered, and dried to obtain a powdery rubber-containing graft copolymer (I-2). The graft ratio of this rubber-containing graft copolymer (I-2) was 45%.

(Reference Example 2) Manufacture of vinyl copolymer (II) (1) Manufacture of vinyl copolymer (II-1) In a stainless steel autoclave having a capacity of 20 liters and equipped with a baffle and a fiddle-type stirring blade. A solution prepared by dissolving 0.05 part of methyl acrylate / acrylamide copolymer prepared by the radical polymerization method in water described in Example 1 of JP-B-45-24151 in 165 parts of ion-exchanged water was added. 400r. p. m. And the inside of the system was replaced with nitrogen gas. Next, the following mixed substances were added while stirring the reaction system, and the temperature was raised to 60 ° C. to initiate polymerization.
<Mixed substance>
• Styrene: 70 parts • Acrylonitrile: 30 parts • t-dodecyl mercaptan: 0.05 parts • 2,2′-azobisisobutyronitrile: 0.4 parts • Deionized water: 150 parts Specifically, 15 minutes The reaction temperature was raised to 65 ° C. over 50 minutes, and then raised to 100 ° C. over 50 minutes. Thereafter, the reaction system was cooled, the polymer was separated, washed and dried in accordance with ordinary methods to obtain a vinyl copolymer (II-1).

(2) Production of vinyl-based copolymer (II-2) A stainless steel autoclave having a capacity of 20 liters and equipped with a baffle and a fiddle-type stirring blade was added to the water described in Example 1 of Japanese Examined Patent Publication No. 45-24151. A solution prepared by dissolving 0.05 part of methyl acrylate / acrylamide copolymer prepared by the radical polymerization method in 165 parts of ion-exchanged water was added to 400 r. p. m. And the inside of the system was replaced with nitrogen gas. Next, the following mixed substances were added while stirring the reaction system, and the temperature was raised to 60 ° C. to initiate polymerization.
<Mixed substance>
・ Methyl methacrylate: 80 parts ・ Styrene: 15 parts ・ Acrylonitrile: 5 parts ・ t-dodecyl mercaptan: 0.05 parts ・ 2,2′-azobisisobutyronitrile: 0.4 parts ・ Deionized water: 150 Part Specifically, after raising the reaction temperature to 65 ° C. over 15 minutes, the temperature was raised to 100 ° C. over 50 minutes. Thereafter, the reaction system was cooled, the polymer was separated, washed and dried according to the usual method to obtain a vinyl copolymer (II-2).

(3) Production of vinyl-based copolymer (II-3) A stainless steel autoclave having a capacity of 20 liters and equipped with a baffle and a foudra-type stirring blade was added to the water described in Example 1 of Japanese Examined Patent Publication No. 45-24151. A solution obtained by dissolving 0.05 part of methyl acrylate / acrylamide copolymer prepared by the radical polymerization method in 165 parts in ion-exchanged water was stirred at 400 rpm, and the system was replaced with nitrogen gas. Next, the following mixed substances were added while stirring the reaction system, and the temperature was raised to 60 ° C. to initiate polymerization.
<Mixed substance>
-Methyl methacrylate: 20 parts-Styrene: 75 parts-Acrylonitrile: 5 parts-t-dodecyl mercaptan: 0.05 parts-2,2'-azobisisobutyronitrile: 0.4 parts-Deionized water: 150 Part Specifically, after raising the reaction temperature to a temperature of 65 ° C. over 15 minutes, the temperature was raised to a temperature of 100 ° C. over 50 minutes. Thereafter, the reaction system was cooled, the polymer was separated, washed and dried in accordance with ordinary methods to obtain a vinyl copolymer (II-3).

(Reference Example 3) Aliphatic polyester (III)
Polylactic acid (weight-average molecular weight 200,000, D-lactic acid unit 1%, melting point 175 ° C. poly-L-lactic acid) manufactured by NatureWorks was used.

(Reference Example 4) Unsaturated carboxylic acid alkyl ester (d) (co) polymer (IV)
A polymethyl methacrylate resin “Acrypet G” (registered trademark) manufactured by Kuraray Co., Ltd. was used.

Reference Example 5 Titanium oxide (V)
(1) R980 (rutile type, primary particle size 0.25 μm) manufactured by Ishihara Sangyo Co., Ltd. was used (V-1).
(2) A220 (Anatase type, primary particle size 0.16 μm) manufactured by Ishihara Sangyo Co., Ltd. was used (V-2).

(Examples 1-9)
The rubber-containing graft copolymer (I) prepared in the above Reference Example 1, the vinyl copolymer (II) prepared in the above Reference Example 2, and the aliphatic polyester prepared in the above Reference Example 3 ( III), the unsaturated carboxylic acid alkyl ester (d) (co) polymer (IV) of Reference Example 4 and the titanium oxide (V) of Reference Example 5 described above are shown in Table 1, respectively. Then, after mixing at a temperature of 23 ° C. using a Henschel mixer, the obtained mixture was put into a vented 30 mmφ twin screw extruder (Ikegai Iron Works, PCM-30), and melt-kneaded at a temperature of 230 ° C., By extruding, a pellet-shaped thermoplastic resin composition was obtained. Next, this pellet-shaped resin composition was put into an injection molding machine (“Promat” (registered trademark) 40/25, manufactured by Sumitomo Heavy Industries), and each test piece was molded under an injection pressure of a filling lower limit pressure of +1 MPa. The physical properties were measured. The results are shown in Table 1.

(Comparative Examples 1-6)
Rubber-containing graft copolymer (I) prepared in Reference Example 1 above, vinyl copolymer (II) prepared in Reference Example 2, aliphatic polyester (III) prepared in Reference Example 3, The unsaturated carboxylic acid alkyl ester (d) (co) polymer (IV) and titanium oxide (V) of Reference Example 4 described above were used at a temperature of 23 ° C. using a Henschel mixer at the blending ratio shown in Table 2. After mixing, the resulting mixture is put into a vented 30 mmφ twin screw extruder (Ikegai Iron Works, PCM-30), melt kneaded at a temperature of 230 ° C., and extruded to give a pellet-shaped thermoplastic resin. A composition was obtained. Next, this pellet-shaped resin composition was put into an injection molding machine (“Promat” (registered trademark) 40/25, manufactured by Sumitomo Heavy Industries, Ltd.), and each test piece was molded at an injection pressure of a filling lower limit pressure + 1 MPa. The physical properties were measured. The results are shown in Table 2.

  The thermoplastic resin composition molded bodies obtained from the thermoplastic resin compositions of Examples 1 to 9 of the present invention were excellent in the balance of physical properties of molded article appearance, impact resistance and heat resistance. However, the molded products obtained from the thermoplastic resin compositions obtained in Comparative Examples 1, 5, and 6 have an unsaturated carboxylic acid alkyl ester content and an unsaturated carboxylic acid alkyl ester content / aliphatic polyester content according to the present invention. Therefore, the appearance of the molded product was inferior. The thermoplastic resin composition molded article obtained in Comparative Example 2 has an added amount of unsaturated carboxylic acid alkyl ester polymer outside the scope of the present invention, and the thermoplastic resin composition molded article obtained in Comparative Example 4 Since the addition amount of titanium oxide was outside the range of the present invention, both had poor impact resistance. The thermoplastic resin composition molded body obtained in Comparative Example 3 was inferior in the appearance of the molded product because the amount of titanium oxide added was outside the scope of the present invention.

  The thermoplastic resin composition of the present invention is useful because it can be widely used in various applications because a molded product having an excellent appearance can be obtained by molding. The molded product obtained by molding the thermoplastic resin composition of the present invention is suitable for housings such as OA equipment and home appliances, parts thereof, various general goods and sheets.

FIG. 1 is a schematic side view for explaining a mold used in an embodiment of the present invention.

Claims (9)

10 to 50 parts by weight of a rubber-containing graft copolymer (I) obtained by graft copolymerizing a vinyl monomer or a vinyl monomer mixture with a rubber polymer (a), at least two kinds of vinyl monomers Vinyl copolymer (II) 5 to 40 parts by weight, aliphatic polyester (III) 10 to 60 parts by weight, and unsaturated carboxylic acid alkyl ester (d) (co) polymer (IV) ) 5 to 50 parts by weight, and further containing 2 to 10 parts by weight of titanium oxide (V) with respect to (I) + (II) + (III) + (IV) = 100 parts by weight. A thermoplastic resin composition comprising 20% by weight or more of an unsaturated carboxylic acid alkyl ester (d) in the resin composition and satisfying the following formula:
0.6 ≦ unsaturated carboxylic acid alkyl ester (d) content (% by weight) / aliphatic polyester (III) content (% by weight)   The rubber-containing graft copolymer (I) is converted into a rubbery polymer (a), an aromatic vinyl monomer (b), a vinyl cyanide monomer (c), an unsaturated carboxylic acid alkyl ester monomer. Rubber-containing graft copolymer obtained by graft copolymerization of a vinyl monomer or a vinyl monomer mixture selected from the group consisting of a monomer (d) and other copolymerizable vinyl monomers (e) The thermoplastic resin composition according to claim 1, which is a coalescence.   The rubber-containing graft copolymer (I) is added to the rubbery polymer (a) by 10 to 80% by weight of the aromatic vinyl monomer (b) and from 0 to 20% by weight of the vinyl cyanide monomer (c). %, Graft copolymer of 20 to 90% by weight of unsaturated carboxylic acid alkyl ester monomer (d) and other vinyl monomer (e) capable of copolymerization (e) The thermoplastic resin composition according to claim 1 or 2, which is a copolymer.   The vinyl copolymer (II) contains an aromatic vinyl monomer (b), a vinyl cyanide monomer (c), an unsaturated carboxylic acid alkyl ester (d) and other copolymerizable vinyl monomers. The thermoplastic resin composition according to any one of claims 1 to 3, which is a vinyl copolymer obtained by copolymerizing at least two kinds of vinyl monomers selected from the group consisting of monomers (e). .   The vinyl copolymer (II) is an aromatic vinyl monomer (b) 20 to 85% by weight, a vinyl cyanide compound (c) 1 to 55% by weight, an unsaturated carboxylic acid alkyl ester (d) 0 to 5. A vinyl copolymer obtained by copolymerizing 79% by weight and 0 to 50% by weight of another copolymerizable vinyl monomer (e). Thermoplastic resin composition.   Unsaturated carboxylic acid in composition comprising rubber-containing graft copolymer (I), vinyl copolymer (II) and at least one unsaturated carboxylic acid alkyl ester (d) (co) polymer (IV) The thermoplastic resin composition according to any one of claims 1 to 5, wherein the copolymerization rate of the alkyl ester monomer (d) is 5% by weight or more.   The thermoplastic resin composition according to any one of claims 1 to 6, wherein the aliphatic polyester (III) is polylactic acid.   The thermoplastic resin composition according to claim 1, wherein the titanium oxide (V) is a rutile type titanium oxide.   A molded product formed by molding the thermoplastic resin composition according to claim 1.

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