JP2011099048A - Thermoplastic resin composition and molded product thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoplastic resin composition of the polylactic acid resin type which can obtain molded articles having good external appearance even in deep colored articles and, in addition, balanced mechanical properties and heat resistance. <P>SOLUTION: The thermoplastic resin includes a rubber-containing graft copolymer as component (A), a vinylic copolymer as component (B), a (meth)acrylic ester polymer as component (C), and a polylactic acid resin as component (D) and as each of component (A) to component (D), component (A) is 15-60 wt.%; component (B) is 10-55 wt.%; component (C) is 0-50 wt.%; and component (D) is 5-55 wt.%, and relationship in the melt viscosity at 220°C and 1,000 s<SP>-1</SP>between a resin composition (E) composed only of the vinylic copolymer as component (B) and the (meth)acrylic ester polymer as component (C) and the polylactic acid resin as component (D) is in the range of 0.30≤η of component (D)/η of component (E)≤0.80. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a polylactic acid resin-based thermoplastic resin composition from which a molded article having an excellent appearance during molding is obtained, and relates to a molded article having an excellent appearance formed by molding the thermoplastic resin composition It is.

  Conventional injection molding materials have been used in various fields such as polyethylene resin, polypropylene resin, nylon resin, polyester resin, ABS resin, polycarbonate resin, and polyacetal resin. After use of the product, it has been disposed of by landfill or incineration, which has put a heavy burden on the global environment, such as semi-permanent residual in the ground or generation of carbon dioxide during incineration. In recent years, the rise of carbon dioxide, a greenhouse gas, has been pointed out as a cause of global warming, and the momentum for suppressing carbon dioxide emissions on a global scale has increased. From such a viewpoint of environmental conservation, as a renewable resin, utilization of plant resources that absorb and fix carbon dioxide has attracted attention, and alternative studies of petroleum resources have been made. Plant-derived plastics that are able to reduce the amount of petroleum raw materials used and reduce carbon dioxide emissions have also attracted attention as materials for injection molding.

  As such plant-derived resins, aliphatic polyesters including polylactic acid resins have been studied, but various improvements have been made because they are inferior in mechanical strength and heat resistance compared to the above-described existing petroleum resins. Consideration is being made. As the improvement technique, not only the improvement of the polylactic acid resin itself, but also various properties are actively improved by the polymer alloy with the existing resin.

  One of them is the study of adding the characteristics of ABS resin to polylactic acid resin by alloying ABS resin and polylactic acid resin having excellent characteristics such as moldability, secondary workability, and surface appearance. It is made mainly by ABS resin manufacturers, and many ABS resins and polylactic acid resins are commercially available. However, the conventional ABS resin / polylactic acid resin alloy material tends to have an appearance of the weld part and a flow mark of the non-weld part when injection molding is performed, and the application of the ABS resin to the external parts of the main use is limited. was there.

  The following Patent Documents 1 to 6 have been proposed as attempts to improve these, but the surface appearance of the injection-molded product is improved as compared with the conventional ABS resin / polylactic acid resin alloy. ABS resin / polylactic acid resin alloy is often used by adding a colorant, and is insufficient in that a flow mark or a weld line may be noticeable depending on a colored color. Furthermore, in Patent Document 7, by adding a large amount of a specific unsaturated carboxylic acid alkyl ester and a colorant titanium oxide, a molded product having a good appearance can be obtained for light colors and light colors. However, since a large amount of white titanium oxide is added, there is a problem that it is difficult to cope with dark colors.

JP 2009-209263 A JP 2009-197079 A JP 2009-132777 A JP 2009-132767 A JP 2009-13339 A JP 2009-7528 A JP 2008-214469 A

  The object of the present invention is to solve the problems shown in the background art and not only to obtain a molded product having a good appearance even in a dark colored product, but also a heat of polylactic acid resin system that balances mechanical properties and heat resistance. An object of the present invention is to provide a molded article excellent in appearance, which is a plastic resin composition, which is formed by molding the thermoplastic resin composition.

  The inventors of the present invention have arrived at the present invention as a result of intensive studies to solve the above problems. That is, this invention is comprised by the following (1)-(6).

(1) Rubber component (a) 30 to 70 parts by weight as component (A) and vinyl cyanide monomer (i) 0 to 10% by weight, aromatic vinyl monomer (c) 10 to 40 A rubber-containing graft copolymer obtained by graft-polymerizing 70 to 30 parts by weight of a monomer mixture consisting of 50% by weight and 50 to 90% by weight of an acrylic ester monomer (d), and at least cyanide as component (B) It is composed of 0 to 10% by weight of vinyl monomer (A), 10 to 40% by weight of aromatic vinyl monomer (c) and 50 to 90% by weight of (meth) acrylic acid ester monomer (d). A vinyl-based copolymer obtained by copolymerizing a monomer mixture, a (meth) acrylic acid ester-based polymer as a component (C), and a thermoplastic resin composition containing a polylactic acid resin as a component (D), ,
The components (A) to (D) are 15 to 60% by weight of the component (A), 10 to 55% by weight of the component (B), 0 to 50% by weight of the component (C), and 5 to 55 of the component (D). % By weight
In addition, a resin composition (E) composed of a component (B) vinyl copolymer and a component (C) (meth) acrylate polymer and a component (D) polylactic acid resin are melted at 220 ° C. and 1000 s ⁻¹ . A thermoplastic resin composition having a viscosity (η) relationship in the following range.
0.30 ≦ η component (D) / η component (E) ≦ 0.80.

  (2) The monomer mixture of the component (A) is a vinyl cyanide monomer (ii) 2 to 8% by weight, an aromatic vinyl monomer (c) 10 to 40% by weight and an acrylic ester. The thermoplastic resin composition according to (1), comprising 50 to 85% by weight of the monomer (d).

  (3) The vinyl copolymer of the component (B) is at least 2 to 8% by weight of vinyl cyanide monomer (ii), 10 to 40% by weight of aromatic vinyl monomer (c) and acrylic. The thermoplastic resin composition according to (1) or (2), which is obtained by copolymerizing a monomer mixture consisting of 50 to 85% by weight of an acid ester monomer (d).

(4) The SP value of the mixture of (a), (c), (d), component (B) and component (C) other than the rubbery polymer in the rubber graft copolymer of component (A) is 19 The thermoplastic resin composition according to any one of (1) to (3), which is in a range of .8 to 21.1 (J / cm ³ ) ^1/2 .

  (5) The thermoplastic resin according to any one of (1) to (4), comprising 0.1 to 10 parts by weight of a carbodiimide compound with respect to 100 parts by weight of the component (D) polylactic acid resin. Composition.

  (6) A molded product obtained by molding the thermoplastic resin composition according to any one of (1) to (5).

  According to the present invention, not only a molded product having a good appearance even in a dark-colored product, but also a polylactic acid resin-based thermoplastic resin composition having a good balance between mechanical properties and heat resistance, the present thermoplastic resin composition It is possible to provide a molded product having an excellent appearance formed by molding a product.

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

  The thermoplastic resin composition of the present invention comprises component (A) rubber-containing graft copolymer, component (B) vinyl copolymer, component (C) (meth) acrylic acid ester polymer, component (D) poly It is a thermoplastic resin composition comprising a lactic acid resin.

  The rubber-containing graft copolymer of component (A) comprises a rubbery polymer (a), a vinyl cyanide monomer (A), an aromatic vinyl monomer (U), and an acrylate monomer. It is obtained by graft polymerization of a monomer mixture comprising (D).

  Examples of the rubbery polymer (a) constituting the rubber-containing graft copolymer of the component (A) include diene rubber, acrylic rubber, ethylene rubber, and the like. 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), Examples include ethylene-propylene rubber, ethylene-propylene-diene rubber, poly (ethylene-isobutylene), poly (ethylene-methyl acrylate), and poly (ethylene-ethyl acrylate). The rubbery polymer (a) is not limited to the use of one of those exemplified above, and two or more types can be mixed and used. Among them, as the rubbery polymer (a), polybutadiene and poly (butadiene-styrene) are preferably used, and polybutadiene is more preferably used from the viewpoint of impact resistance improvement effect.

  The weight average particle diameter of the rubbery polymer (a) is preferably in the range of 0.1 to 2.0 μm, more preferably 0, from the viewpoint of impact resistance, molding processability, fluidity and appearance. .15 to 1.5 μm.

  Examples of the vinyl cyanide monomer (A) constituting the component (A) include acrylonitrile, methacrylonitrile, etaacrylonitrile and the like, and acrylonitrile is preferably used. These vinyl cyanide monomers (i) do not necessarily need to be used alone, and can be used in combination of two or more.

  Examples of the aromatic vinyl monomer (c) constituting the component (A) include styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, t-butylstyrene, o-ethylstyrene, o-chloro. Styrene and o, p-dichlorostyrene are exemplified, and styrene and α-methylstyrene are preferably used. These aromatic vinyl monomers (c) do not necessarily need to be used alone, and may be used as a mixture of two or more.

  Examples of the (meth) acrylate monomer (d) constituting the component (A) include methyl methacrylate, methyl acrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, and butyl methacrylate. However, methyl acrylate and methyl methacrylate are preferably used, and particularly preferred is methyl methacrylate. These (meth) acrylic acid ester monomers (d) are not necessarily used alone, and may be used in combination of two or more.

  Furthermore, in addition to the essential components constituting the component (A), monomers capable of copolymerization can be applied within a range that does not impair the properties, for example, N-methylmaleimide, N-cyclohexylmaleimide and N -Maleimide compounds, such as phenylmaleimide, and unsaturated amides, such as acrylamide, may be mentioned. These are not necessarily used alone, and may be used in a mixture of two or more.

  The ratio of the rubber-like polymer (a) in the rubber-containing graft copolymer of the component (A) is 30 to 70 parts by weight, preferably 35 to 60 parts by weight, more preferably 40 to 55 parts by weight. . When the amount is less than 30 parts by weight, the impact resistance of the resin composition may be lowered. On the other hand, when an amount exceeding 70 parts by weight is added, the molding processability deteriorates, and the appearance of the molded product flows. Defects such as marks are likely to occur.

  The proportion of the component (A) vinyl cyanide monomer (A) is 0 to 10% by weight of the monomer mixture, preferably 2 to 8% by weight, more preferably 3 to 6% by weight. . When the proportion of the vinyl cyanide monomer (A) exceeds 10% by weight, the appearance of the molded product made of the resin composition of the present invention, particularly the appearance of the weld portion, may be deteriorated.

  Moreover, the ratio of the aromatic vinyl-type monomer (u) in a component (A) is 10-40 weight% of a monomer mixture, Preferably it is 15-35 weight%, More preferably, it is 20-30 weight% %. If the ratio of the aromatic vinyl monomer (c) is less than 10% by weight, the moldability may be lowered, and if it exceeds 40% by weight, the impact resistance is lowered or the molded product made of the resin composition of the present invention. In particular, the appearance of the weld portion may deteriorate.

  Furthermore, the proportion of the (meth) acrylic acid ester monomer (e) is 50 to 90% by weight of the monomer mixture, preferably 60 to 80% by weight, more preferably 65 to 75% by weight. If the proportion of the (meth) acrylic acid ester monomer (e) is less than 50% by weight, the appearance of the molded product, particularly the welded portion, may be deteriorated. On the other hand, if it exceeds 90% by weight, the molded product There is no problem with the appearance and the weld appearance, but the impact resistance may be reduced.

  The graft ratio in the rubber-containing graft copolymer of component (A) is preferably in the range of 15 to 80%, and more preferably in the range of 20 to 70% by weight. If the graft ratio is less than 15%, the impact resistance may be lowered, and if it exceeds 80%, the molding processability is deteriorated and a defect such as a flow mark is likely to occur in the appearance of the molded product.

  The rubber-containing graft copolymer of component (A) can be produced by any polymerization method such as emulsion polymerization, suspension polymerization, bulk polymerization, and solution polymerization. In addition, there is no particular limitation on the charging method of each monomer, and initial batch charging, or in order to suppress the composition distribution of the copolymer, some or all of the charged monomers are charged or polymerized continuously or divided. May be.

  The vinyl copolymer of component (B) comprises at least a vinyl cyanide monomer (ii), an aromatic vinyl monomer (c) and a (meth) acrylic acid ester monomer (d). It is obtained by copolymerizing a monomer mixture. Here, as the vinyl cyanide monomer (A), aromatic vinyl monomer (U) and (meth) acrylic acid ester monomer (E) constituting the component (B), The same type of monomers (A), (U) and (E) described in the above-mentioned component (A) rubber-containing graft copolymer are used. The same applies to monomers that can be copolymerized in addition to the above.

  The proportion of the vinyl cyanide monomer (A) in the component (B) is 0 to 10% by weight, preferably 2 to 8% by weight, more preferably 3 to 6% by weight. When the proportion of the vinyl cyanide monomer (A) exceeds 10% by weight, the appearance of the molded product made of the resin composition of the present invention, particularly the appearance of the weld portion, may be deteriorated.

  Moreover, the ratio of the aromatic vinyl-type monomer (u) in a component (B) is 10 to 40 weight%, Preferably it is 15 to 35 weight%, More preferably, it is 20 to 30 weight%. If the ratio of the aromatic vinyl monomer (c) is less than 10% by weight, the moldability may be lowered, and if it exceeds 40% by weight, the impact resistance is lowered or the molded product made of the resin composition of the present invention. In particular, the appearance of the weld portion may deteriorate.

  Further, the proportion of the (meth) acrylic acid ester monomer (e) is 50 to 90% by weight, preferably 60 to 80% by weight, more preferably 65 to 75% by weight. When the proportion of the (meth) acrylic acid ester monomer (d) is less than 50% by weight, the appearance of the molded product, particularly the weld part, may be deteriorated. On the other hand, when it exceeds 90% by weight. Although there is no problem with the appearance of the molded product and the appearance of the weld, the impact resistance may be lowered.

  The intrinsic viscosity at 30 ° C. of the solution prepared to a concentration of 0.4 g / dl of methyl ethyl ketone of the vinyl copolymer of component (B) is preferably 0.25 to 1.50 dl / g, 0.30 ˜1.20 dl / g is more preferable, and 0.30 to 1.10 dl / g is more preferable. If the intrinsic viscosity is less than 0.25, the strength of the molded product of the resin composition, particularly impact strength, may be reduced. On the other hand, if it exceeds 1.50, the fluidity at the time of injection molding is impaired, Not only is the appearance of the molded product impaired, but there is a risk that molding will not be possible with a large molded product.

  The component (B) vinyl copolymer can be produced by any polymerization method such as emulsion polymerization, suspension polymerization, bulk polymerization, and solution polymerization. In addition, there is no particular limitation on the charging method for each monomer, and initial batch charging or polymerization is performed while charging a part or all of the charged monomer continuously or dividedly in order to suppress the composition distribution of the copolymer. May be.

  The component (C) (meth) acrylic acid ester polymer is a polymer composed of methyl methacrylate, methyl acrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate and the like. These are not necessarily a single polymer, and two or more types of copolymerized polymers can also be used. Further, two or more homopolymers can be blended and used. Among these, in the present invention, polymethyl methacrylate obtained by polymerizing methyl methacrylate can be preferably used.

  The component (D) polylactic acid resin is a polymer mainly composed of L-lactic acid and / or D-lactic acid, but may contain other copolymerization components other than lactic acid. As monomer units as other copolymer components, ethylene glycol, polypropylene glycol, butanediol, heptanediol, hexanediol, octanediol, nonanediol, decanediol, 1,4-cyclohexanediol, neopentyl glycol, glycerin, 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.

  The polylactic acid resin of component (D) includes, for example, a polymer mainly composed of aliphatic hydroxycarboxylic acid, and a polymer mainly composed of aliphatic polycarboxylic acid and aliphatic polyhydric alcohol. And other types of aliphatic polyester resins. Examples of the polymer having an aliphatic hydroxycarboxylic acid as a main constituent component include polyglycolic acid, poly-3-hydroxybutyric acid, poly-4-hydroxybutyric acid, poly-4-hydroxyvaleric acid, poly-3-hydroxyhexanoic acid, and polylactone. Is mentioned. 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. The aliphatic polyester resin that can be used in addition to the polylactic acid resin is not necessarily used alone, and can be used as a mixture or copolymer of two or more kinds.

  The molecular weight and molecular weight distribution of the polylactic acid resin of the component (D) 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, Especially preferably, it is 40,000 or more. 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. The melting point of the polylactic acid resin is preferably 90 ° C or higher, more preferably 150 ° C or higher.

  Moreover, in order to obtain high heat resistance by using polylactic acid resin, it is preferable that the optical purity of the lactic acid component is high, and among the total lactic acid component, 80 mol% or more of L-form or D-form is contained. More preferably, it is preferably 90 mol% or more, more preferably 95 mol% or more.

  As a method for producing the polylactic acid resin of component (D), a known polymerization method can be used, and a direct polymerization method from lactic acid or a ring-opening polymerization method via lactide can be employed.

  In the thermoplastic resin composition of the present invention, the components (A) to (D) are each composed of 15 to 60% by weight of component (A), 10 to 55% by weight of component (B), and 0 to (C) of component (C). It is necessary to be 50% by weight and 5 to 55% by weight of component (D).

  When the component (A) rubber-containing graft copolymer is less than 15% by weight, the impact resistance of the resin composition may be reduced. On the other hand, when it exceeds 60% by weight, the flow during injection molding may be reduced. Not only the appearance of the molded product is impaired, but also a large molded product may not be molded. A preferred ratio of the component (A) in the thermoplastic resin composition of the present invention is 20 to 50% by weight, more preferably 30 to 40% by weight.

  When the component (B) vinyl copolymer is less than 10% by weight, the fluidity of the resin may be impaired, and the appearance of the molded product may be deteriorated. May decrease. A preferred ratio of the component (B) in the thermoplastic resin composition of the present invention is 20 to 50% by weight, more preferably 20 to 40% by weight.

  When the amount of component (C) (meth) acrylic acid ester polymer added exceeds 50% by weight, the impact resistance of the resin composition may be impaired. A preferred ratio of the component (C) in the thermoplastic resin composition of the present invention is 30% by weight or less, more preferably 20% by weight or less.

  When the component (D) polylactic acid resin is less than 5%, there is no problem such as moldability, but the effect is extremely small to achieve the fundamental purpose of reducing carbon dioxide, while when it exceeds 55% by weight The heat resistance of the resin composition is greatly reduced. A desirable ratio of the component (D) polylactic acid resin in the thermoplastic resin composition of the present invention is 10 to 50% by weight, and more preferably 25 to 50% by weight.

Further, in the thermoplastic resin composition of the present invention, the resin composition (E) comprising the component (B) vinyl copolymer and the component (C) (meth) acrylate polymer and the component (D) poly The relationship of melt viscosity (η) at 220 ° C. and 1000 s ⁻¹ of the lactic acid resin needs to be in the following range.
0.30 ≦ η component (D) / η component (E) ≦ 0.80.

When the ratio of the melt viscosity represented by the above formula is less than 0.30, the appearance of the molded product may be impaired, the fluidity at the time of injection molding is insufficient, and it cannot be molded depending on the size of the molded product. Sometimes. On the other hand, when it exceeds 0.80, the flowability is not a problem, but the strength of the resin composition may be insufficient. The melt viscosity at 220 ° C. and 1000 s ⁻¹ is preferably in the range of 0.40 to 0.70, and more preferably in the range of 0.45 to 0.65. The melt viscosity can be calculated by using the values of the orifice at a length of 20 mm, a diameter of 1 mm, 220 ° C., and a shear rate of 1000 s ⁻¹ .

  It is preferable that 0.1-10 weight part of carbodiimide compounds are contained in the thermoplastic resin composition of this invention with respect to 100 weight part of component (D) polylactic acid resin. The thermoplastic resin composition of the present invention contains 0.1 to 10 parts by weight of a carbodiimide compound with respect to 100 parts by weight of the component (D) polylactic acid resin, whereby the terminal carboxyl group of the polylactic acid resin is blocked and moisture resistance is increased. Thermal properties are improved. In addition, the use of less than 0.1 parts by weight of the carbodiimide compound relative to 100 parts by weight of the component (D) polylactic acid resin does not show the effect of blocking the terminal carboxyl group of the polylactic acid resin, while it is used in excess of 10 parts by weight. In such a case, the mold may be soiled, which is not preferable when the thermoplastic resin composition is continuously molded.

  Specific examples of the carbodiimide compound used in the present invention include N, N′-di-2,6-diisopropylphenylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, dibutyl as monocarbodiimide having one carbodiimide group in the same molecule. Carbodiimide, di-tert-butylcarbodiimide, dioctylcarbodiimide, N, N′-di-o-tolylcarbodiimide, N, N′-di-p-tolylcarbodiimide, N, N′-diphenylcarbodiimide, N, N′-dioctyl Decylcarbodiimide, N, N'-di-2,6-dimethylphenylcarbodiimide, N-tolyl-N'-cyclohexylcarbodiimide, N, N'-di-2,6-di-tertbutylphenylcarbodiimide, N-tolyl- N'-Feni Carbodiimide, N, N′-di-p-nitrophenylcarbodiimide, N, N′-di-p-aminophenylcarbodiimide, N, N′-di-p-hydroxyphenylcarbodiimide, N, N′-di-cyclohexylcarbodiimide P-phenylene-bis-di-o-tolylcarbodiimide, p-phenylene-bis-dicyclohexylcarbodiimide, hexamethylene-bis-dicyclohexylcarbodiimide, ethylene-bis-diphenylcarbodiimide, N, N'-dibenzylcarbodiimide, N-octadecyl -N'-phenylcarbodiimide, N-octadecyl-N'-tolylcarbodiimide, N-benzyl-N'-phenylcarbodiimide, N-cyclohexyl-N'-tolylcarbodiimide, N-tolyl-N'-phenylcarbodiimide N, N′-di-p-ethylphenylcarbodiimide, N, N′-di-o-ethylphenylcarbodiimide, N, N′-di-o-isopropylphenylcarbodiimide, N, N′-di-p-isopropyl Phenylcarbodiimide, N, N'-di-2,6-diethylphenylcarbodiimide, N, N'-di-2-isobutyl-6-isopropylphenylcarbodiimide, N, N'-di-2,4,6-trimethylphenyl Examples thereof include carbodiimide, N, N′-di-2,4,6-triisopropylphenylcarbodiimide, N, N′-di-2,4,6-triisobutylphenylcarbodiimide and the like.

  Examples of the polycarbodiimide having two or more carbodiimide groups in the same molecule include aliphatic (alicyclic) polycarbodiimides (for example, Nisshinbo Co., Ltd. “Carbodilite LA-1”, “HMV-8CA”, etc.), aromatic Group polycarbodiimides (for example, “STABAKZOL P”, “STABAKZOL P-100”, etc., manufactured by Rheinhemy) and the like, preferably “carbodilite HMV-8CA” is used.

In addition, the thermoplastic resin composition of the present invention comprises (A), (U), (D) component, and component (B) other than the rubbery polymer (A) in the component (A) rubber-containing graft copolymer. The SP value (compatibility parameter) of the mixture of component (C) is preferably in the range of 19.8 to 21.1 (J / cm ³ ) ^1/2 . This SP value is calculated by SP method proposed by Robert F. Fedors (Reference: Polymer Engineering and Science, February, 1974, Vol.14, No2, Title: A Method for Estimating Both The Solubility Parameters and Molar Volumes of Liquids). When the SP value is less than 19.8 (J / cm ³ ) ^1/2 or exceeds 21.1 (J / cm ³ ) ^1/2 , the compatibility of the entire resin composition may be reduced. Yes, the appearance of the welded part of the molded product may be impaired. A preferable SP value range is 20.0 to 21.1 (J / cm ³ ) ^1/2 in the sense of achieving both the mechanical properties and the appearance of the molded product, and more preferably 20.2 to 20.8 ( J / cm ³ ) ^1/2 .

  In addition, components (A), (U), (E) other than the rubbery polymer (A) of the rubber-containing graft copolymer, components (B) vinyl copolymer and component (C) ) At 23 ° C. is preferably in the range of 1.485 to 1.530. When a material having a refractive index value of less than 1.485 is used, the appearance of the molded product may be impaired. On the other hand, when the refractive index value exceeds 1.530, the appearance of the weld portion of the molded product may be impaired. A preferable range in the sense of achieving both the mechanical properties and the appearance of the molded product is 1.490 to 1.525, and more preferably 1.505 to 1.520.

  Other resins can also be added to the thermoplastic resin composition of the present invention within a range not impairing the effects of the present invention. Examples of resins that can be added include polyvinyl chloride, polyolefins such as polyethylene and polypropylene, polyamides such as nylon 6, nylon 66, nylon 4, 6, and nylon 6T, polyethylene terephthalate, polybutylene terephthalate, and polycyclohexanedimethyl terephthalate. Examples thereof include polyester, polycarbonate, polyarylate, polyoxymethylene, polyphenylene oxide, polyphenylene sulfide and the like. These do not necessarily need to be used alone, and can be used in combination of two or more.

  Moreover, various elastomers can also be added to the thermoplastic resin composition of the present invention within a range not impairing the effects of the present invention. Ethylene / methyl acrylate copolymer, ethylene / ethyl acrylate copolymer, ethylene / butyl acrylate copolymer, ethylene / ethyl acrylate / carbon monoxide copolymer, ethylene / glycidyl methacrylate copolymer, ethylene / methyl acrylate / glycidyl Polyolefin rubbers such as methacrylate copolymers, ethylene / butyl acrylate / glycidyl methacrylate copolymers, ethylene / octene-1 copolymers, ethylene / butene-1 copolymers, or carboxyl groups, anhydrous carboxyl groups, epoxy groups, It is selected from polyolefin rubber modified with oxazoline group or the like. These are not necessarily used alone, and two or more kinds can be used in combination.

  The thermoplastic resin composition of the present invention includes a hindered phenol-based antioxidant, a sulfur-containing compound-based antioxidant, a phosphorus-containing organic compound-based antioxidant, a phenol-based, an acrylate-based, and the like as necessary. , UV absorbers such as benzotriazole, benzophenone, and succinate, decabromobiphenyl ether, tetrabromobisphenol A, chlorinated polyethylene, brominated epoxy oligomer, brominated polycarbonate, antimony trioxide, condensed phosphate, etc. Flame retardants and flame retardant aids, antibacterial agents typified by silver antibacterial agents, antistatic agents, antifungal agents, carbon black, titanium oxide, mold release agents, lubricants, pigments and dyes can also be added. .

  The thermoplastic resin composition of the present invention can be mixed with a crystal nucleating agent as necessary. Specific examples thereof include inorganic fine particles such as talc, silica and graphite, magnesium oxide, aluminum oxide and the like. A metal oxide etc. are mentioned. Among these, inorganic fine particles are preferable, and talc is particularly preferably used.

  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 of the present invention can be obtained by melting each copolymer component constituting the thermoplastic resin composition and mixing each component. With respect to the melt mixing method of each component, a heating device, a melt mixing method using a single or biaxial screw in a cylinder having a vent, and the like can be employed. The heating temperature at the time of melt mixing is usually selected from the range of 210 to 320 (° C.), but it is also possible to freely set the temperature gradient at the time of melt mixing without departing from the object of the present invention. is there. Further, when a biaxial screw is used, it may be in the same rotational direction or in a different rotational direction.

  As the order of melt mixing of the respective components, the graft copolymer (A), the vinyl copolymer (B), the (meth) acrylic acid ester polymer (C) and the polylactic acid resin (D) are initially blended. A resin composition obtained by melt-mixing a graft copolymer (A), a vinyl copolymer (B), and a (meth) acrylic acid ester polymer (C) in advance. The polylactic acid resin (D) is mixed and melted later. Further, when a carbodiimide compound is used, there is no problem even if it is blended in any step, but it is preferably added in a step of blending a polylactic acid resin.

  The thermoplastic resin composition of the present invention obtained as described above is obtained by known methods used for molding of present thermoplastic resins such as injection molding, extrusion molding, blow molding, vacuum molding, compression molding, and gas assist molding. It can be molded and is not particularly limited. Preferably, it is injection molding. The injection molding can be preferably carried out in a temperature range for normal molding of 210 to 260 ° C. Moreover, the mold temperature at the time of injection molding is preferably a temperature range used for normal molding at 30 to 80 ° C.

  The thermoplastic resin composition of the present invention is excellent not only in the appearance of the surface of the molded product and the appearance of the weld part, but also in other characteristics such as impact resistance, so that it can be used in housings for OA equipment, home appliances, etc. Suitable for various parts, miscellaneous goods and sheets.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, these do not limit this invention and can also carry out various deformation | transformation.

  The manufacturing method of the raw material used for the Example is shown below.

Component (A) Rubber-containing graft copolymer <Production method of component A-1>
In a reactor purged with nitrogen, 150 parts by weight of pure water, 0.5 parts by weight of glucose, 0.5 parts by weight of sodium pyrophosphate, 0.005 parts by weight of ferrous sulfate and a weight average rubber particle size of 0.8 μm are obtained. 35 parts by weight of polybutadiene latex was charged, and the temperature in the reactor was increased to 65 ° C. while stirring. The polymerization was started when the internal temperature reached 65 ° C., and styrene (16 parts by weight), acrylonitrile (3 parts by weight), methyl methacrylate (46 parts by weight) and a chain transfer agent t-dodecyl mercaptan mixture (0.2 parts by weight) ) Was continuously added over 4 hours. At the same time, an aqueous solution comprising a polymerization initiator cumene hydroperoxide (0.2 parts by weight) and potassium oleate was continuously added over 7 hours to complete the reaction. To the obtained latex, 1 part of 2,2′-methylenebis (4-methyl-6-tert-butylphenol) was added to 100 parts by weight of latex solids, and the latex was subsequently acid coagulated with sulfuric acid. Sulfuric acid was neutralized with sodium hydroxide, washed, filtered, and dried to obtain a powdery rubber-containing graft copolymer (A-1). The graft ratio of this rubber-containing graft copolymer (A-1) was 45%. Components A-2 to A-8 were prepared in the same manner as A-1, except that the addition amounts shown in Table 1 were used.

Component (B) Vinyl Copolymer <Method for Producing Component B-1>
0.05 parts by weight of a methyl acrylate / acrylamide copolymer produced by a radical polymerization method in water described in Example 1 of JP-B No. 45-24151 was placed in a stainless steel autoclave equipped with a baffle and a foudra type stirring blade. Was dissolved in 165 parts by weight of ion-exchanged water and stirred at 400 rpm, and the system was replaced with nitrogen gas. Next, a total of 100 parts by weight of styrene, acrylonitrile and methyl methacrylate, 0.05 parts by weight of t-dodecyl mercaptan, 0.4 parts by weight of 2,2′-azobisisobutyronitrile, 150 parts by weight of deionized water. Part of the mixed solution was added to the stirred system, and the temperature was raised to 60 ° C. to initiate polymerization. After starting the polymerization, the reaction temperature was raised to 65 ° C over 15 minutes, and then raised to 100 ° C over 50 minutes. Thereafter, the system was cooled to room temperature, and the polymer was separated, washed and dried to obtain a vinyl copolymer (B-1).

  B-1 was prepared at a weight ratio of styrene / acrylonitrile / methyl methacrylate = 24/5/71. The intrinsic viscosity of the obtained B-1 was 0.35 dl / g.

  Components B-2 to B-8 were prepared in the same manner as B-1 except that the ratio of styrene / acrylonitrile / methyl methacrylate shown in Table 2 was changed.

Component (C) (Meth) acrylic acid ester polymer Polymethylmethacrylate resin “SUMIPEX MH” manufactured by Sumitomo Chemical Co., Ltd. was used.

Component (D) Polylactic acid resin 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.

Carbodiimide compound “Carbodilite HMV-8CA” manufactured by Nisshinbo Industries, Ltd. was used.

Method for producing resin composition and method for evaluating physical properties Graft copolymer (A), vinyl copolymer (B), (meth) acrylic acid ester (C) are blended in the compositions shown in Tables 3 and 4, and screw Melt kneading was carried out with a twin screw extruder (temperature range: 220 ° C. to 230 ° C.) rotating in the same direction with a diameter of 30 mm to obtain resin composition pellets. Furthermore, the polylactic acid resin (D) was blended in the ratio shown in Table 3, and 2 parts by weight of carbon black as a colorant was blended in all of 100 parts by weight of (A) to (D). Melt kneading was performed with a 30 mm twin-screw extruder (temperature range: 220 ° C. to 230 ° C.) rotating in the same direction to obtain pellets. In a system using carbodiimide, a predetermined amount was added when blended with the polylactic acid resin. The obtained pellets or raw materials were evaluated by evaluation of physical properties shown in the next section. Moreover, the test piece preparation of physical-property evaluation was produced with the shaping | molding machine (The shaping | molding temperature of 220 degreeC, the mold temperature of 60 degreeC).

  The evaluation methods performed in the examples are shown below. The results are shown in Tables 1-4.

(1) Weight average rubber particle diameter of rubber polymer (a)
Rubber Age Vol.88 p.484-490 (1960), by E. Schmidt, PHBiddison, the sodium alginate method, that is, the fact that the polybutadiene particle size to be creamed varies depending on the concentration of sodium alginate. The particle size of the cumulative weight fraction of 50% was determined from the weight ratio and the cumulative weight fraction of the sodium alginate concentration.

(2) Graft ratio of component (A) rubber-containing graft copolymer 100 ml of acetone was added to a predetermined amount (m; 1 g) of component (A) rubber-containing graft copolymer that had been vacuum-dried at a temperature of 80 ° C. for 4 hours. In addition, the mixture was 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 by the following formula. Here, L is the rubber content of the graft copolymer.
Graft rate (%) = {[(n) − (m) × L] / [(m) × L]} × 100.

(3) Component (B) Intrinsic Viscosity of Vinyl Copolymer Component (B) or Component (C) weighed to 0.2 g was placed in a 50 ml volumetric flask, methyl ethyl ketone solvent was added to 50 ml, and 0.4 g / Intrinsic viscosity was determined with an Ubbelohde viscometer in a high-temperature bath in which the solution of dl was adjusted to 30 ° C.

(4) SP value
It was calculated by the SP value method of the following document proposed by Robert F. Fedors.
Reference: Polymer Engineering and Science, February, 1974, Vol.14, No2
Title: A Method for Estimating Both The Solubility Parameters and Molar Volumes of Liquids.

(5) Refractive index Refractive index of polystyrene: 1.591, Refractive index of polyacrylonitrile: 1.514
Refractive index of polymethyl methacrylate: 1.490
From the mole fraction, the refractive index value of the vinyl copolymer component consisting of (A), (U), and (E) in (A), and (B) the vinyl copolymer (B) is calculated. Calculated.

(6) Melt viscosity The melt viscosity at 220 ° C. and a shear rate of 1000 s ^{−1 was} measured with a capillary graph measuring device (Capillograph type 1C manufactured by Toyo Seiki Seisakusho Co., Ltd.). An orifice having a length of 20 mm and a diameter of 1 mm was used.

(7) MFR (Melt flow rate measurement)
The measurement was performed according to ISO 1133 (measured at a temperature of 220 ° C. and a load of 10N).

(8) Thermal deformation temperature Measured according to ISO75-1, 2 (8) Charpy impact strength Measured according to ISO179.

(9) Weld surface appearance The paintability evaluation test of the molded product was evaluated as follows. Using an injection molding machine, the cylinder temperature is set to 220 ° C. and the mold temperature is set to 60 ° C., and the square plate has an outer dimension of 70 × 240 × 2 mmt and a circular hole with a diameter of 40 mm at a position of 50 mm from the gate. A square plate was formed. The appearance of the weld formed on the side opposite the gate of the circular hole of the square plate was visually observed. The weld portion appearance evaluation was determined by setting the following criteria according to the length of the weld line to be confirmed, and ◎ to Δ were regarded as acceptable levels.
A: Weld line is not seen. O: Weld line is less than 15 mm. Δ: Weld line is 15 mm or more and less than 20 mm. X: Weld line is more than 20 mm.

  When the composition of component (A) or component (B) or the melt viscosity ratio of the thermoplastic main constituent is out of the scope of the present invention from comparison between Examples 1-8 and Comparative Examples 1-8, a molded product It was found that the weld appearance on the surface deteriorated. Moreover, it turned out that fluidity | liquidity falls remarkably and a Charpy impact falls remarkably.

  In comparison between Examples 9 and 10 and Comparative Examples 8 and 9, when the composition ratio of component (A) or component (B) is out of the range of the present invention, the weld appearance of the molded product may be deteriorated. I understood. Moreover, it turned out that fluidity | liquidity falls remarkably and a Charpy impact falls remarkably.

  In the comparison between Examples 11 and 12 and Comparative Example 11, when the composition ratio of the component (C) is outside the range of the present invention, the appearance of the surface of the molded product is not a problem, but the heat resistance of the resin composition itself. It turned out that there is a tendency to fall.

  In comparison between Examples 16 and 17 and Comparative Example 10, when the composition ratio of the component (C) is outside the range of the present invention, there is no problem in appearance, but the Charpy impact property of the resin composition is lowered. I understood that.

  According to the thermoplastic resin composition of the present invention, not only a molded product having a good weld appearance can be obtained even in a dark-colored product, but also the mechanical properties and heat resistance are balanced. It is possible to provide a molded product having an excellent appearance formed by molding a product. The molded article is suitably used for housings such as OA equipment and home appliances, parts thereof, various miscellaneous goods, and sheets.

Claims (6)

30 to 70 parts by weight of rubbery polymer (a) as component (A) and 0 to 10% by weight of vinyl cyanide monomer (ii), 10 to 40% by weight of aromatic vinyl monomer (c) and A rubber-containing graft copolymer obtained by graft polymerization of 70 to 30 parts by weight of a monomer mixture composed of 50 to 90% by weight of an acrylic ester monomer (d), and at least vinyl cyanide monomer as component (B) Monomer consisting of 0 to 10% by weight of monomer (A), 10 to 40% by weight of aromatic vinyl monomer (c) and 50 to 90% by weight of (meth) acrylate monomer (d) A vinyl copolymer obtained by copolymerizing a mixture, a (meth) acrylic acid ester polymer as component (C), and a thermoplastic resin composition containing a polylactic acid resin as component (D),
The components (A) to (D) are 15 to 60% by weight of the component (A), 10 to 55% by weight of the component (B), 0 to 50% by weight of the component (C), and 5 to 55 of the component (D). % By weight
In addition, a resin composition (E) composed of a component (B) vinyl copolymer and a component (C) (meth) acrylate polymer and a component (D) polylactic acid resin are melted at 220 ° C. and 1000 s ⁻¹ . A thermoplastic resin composition, wherein the relationship of viscosity (η) is in the following range.
0.30 ≦ η component (D) / η component (E) ≦ 0.80   The monomer mixture of the component (A) is a vinyl cyanide monomer (ii) 2 to 8% by weight, an aromatic vinyl monomer (c) 10 to 40% by weight and an acrylate ester monomer. The thermoplastic resin composition according to claim 1, comprising 50 to 85% by weight of the body (d).   The vinyl copolymer of the component (B) is at least 2 to 8% by weight of a vinyl cyanide monomer (ii), 10 to 40% by weight of an aromatic vinyl monomer (c) and an acrylate ester The thermoplastic resin composition according to claim 1 or 2, wherein a monomer mixture comprising 50 to 85% by weight of the monomer (d) is copolymerized. The SP value of the mixture of (a), (c), (e), component (B) and component (C) other than the rubbery polymer (a) in the rubber graft copolymer of component (A) is 19 .8～21.1 wherein the ^{(J /} cm ³⁾ is ^1/2 of the range, the thermoplastic resin composition according to any one of claims 1 to 3.   The thermoplastic resin composition according to any one of claims 1 to 4, comprising 0.1 to 10 parts by weight of a carbodiimide compound with respect to 100 parts by weight of the component (D) polylactic acid resin. A molded product formed by molding the thermoplastic resin composition according to claim 1.