JP6981552B2 - Thermoplastic resin compositions and painted products - Google Patents

Description

The present invention relates to a thermoplastic resin composition which is excellent in mechanical properties and heat resistance and can significantly reduce coating defects, and a coated molded product thereof.

Since the polycarbonate resin has excellent heat resistance and impact resistance, it is widely used in a wide range of fields including the fields of automobiles, home appliances, OA equipment, and building materials. However, since the polycarbonate resin alone is inferior in molding processability at the time of injection molding and secondary processability such as plating and painting, it should be alloyed with a rubber-reinforced styrene resin such as ABS resin for the purpose of compensating for the shortcomings of the polycarbonate resin. It has been known.

ABS resin and PC / ABS resin are often used for painting interior and exterior parts, especially in the field of automobiles, and bubble-like coating defects called "armpits" may occur in the coating process. Bubble-like coating defects are closely related to residual strain during molding, and when thinner in the paint permeates, cracks occur in the strained part, and the thinner volatilizes through the cracks, causing bubble-like defects. It is considered. As a countermeasure against the generation of air bubbles, measures such as annealing the molded product before painting to remove residual strain are known, but this annealing treatment requires dedicated equipment, so for the reason of cost increase, A material that does not require annealing has been desired.

As a technique for improving coatability, for example, Patent Document 1 shows that "suction", which is a kind of poor coating, can be suppressed by using a highly cyanated vinyl copolymer. Further, Patent Document 2 shows that the fluidity is improved by using a low cyanide vinyl copolymer. Further, Patent Document 3 shows that the generation of bubbles is suppressed by adding an ethylene / (meth) acrylic acid ester / carbon monoxide copolymer to the heat-resistant ABS.

Japanese Patent Application Laid-Open No. 2019-6920 Japanese Patent Application Laid-Open No. 2015-168814 Japanese Patent Application Laid-Open No. 2012-36384

However, the techniques described in Patent Documents 1 and 2 are insufficient for suppressing the generation of bubbles.
Further, although the technique described in Patent Document 3 is effective in suppressing the generation of bubbles to some extent, there is a problem that the molded product is peeled off from the surface layer at the time of removal from the mold in the injection molding process.

An object of the present invention is to provide a thermoplastic resin composition and a molded product which are excellent in mechanical properties and heat resistance and can significantly suppress the generation of air bubbles during painting.

As a result of diligent studies to solve the above problems, the present inventors have made a polycarbonate resin, a rubber-containing graft copolymer, a vinyl-based copolymer, and an ethylene / acrylic acid ester / anhydrous maleic acid copolymer. We have found that the above problems can be solved by preparing a thermoplastic tree composition containing at least one selected from an ethylene / glycidyl methacrylate copolymer and a polyester elastomer, and have arrived at the present invention. That is, the present invention is composed of the following (1) to (7).
(1) 50 to 70 parts by weight of the polycarbonate resin (A),
Diene-based rubbery polymer (a) A monomer mixture containing at least an aromatic vinyl-based monomer (b) and a vinyl cyanide-based monomer (c) in the presence of 40 to 65% by weight of a monomer mixture 35- 10 to 30 parts by weight of the rubbery-containing graft copolymer (B) obtained by graft-copolymerizing 60% by weight.
It contains 10 to 30 parts by weight of a vinyl-based copolymer (C) obtained by copolymerizing an aromatic vinyl-based monomer and a cyanide vinyl-based monomer.
Ethylene / acrylic acid ester / maleic anhydride as the elastomer component (D) with respect to a total of 100 parts by weight of the polycarbonate resin (A), the rubbery graft copolymer (B) and the vinyl-based copolymer (C). 1 to 5 parts by weight of at least one selected from a copolymer (D-1), an ethylene / glycidyl methacrylate copolymer (excluding graft copolymers) (D-2), and a polyester elastomer (D-3). A thermoplastic resin composition comprising.
(2) The thermoplastic resin composition according to (1) above, wherein the vinyl-based copolymer (C) has a weight average molecular weight in the range of 130,000 to 340,000.
(3) The thermoplastic resin composition according to (1) or (2) above, wherein the average vinyl cyanide content of the vinyl-based copolymer (C) is in the range of 22 to 42% by weight.
(4) The thermoplastic resin composition according to any one of (1) to (3) above, which is used for a molded product for coating.
(5) A molded product for coating, which comprises the thermoplastic resin composition according to any one of (1) to (4) above.
(6) A painted molded product obtained by painting the molded product for painting according to (5) above.
(7) An automobile part comprising the thermoplastic resin composition according to any one of (1) to (4) above.

According to the thermoplastic resin composition of the present invention, it is possible to obtain a molded product having excellent mechanical properties and heat resistance and which can significantly suppress the occurrence of bubble-like coating defects. In addition to suppressing coating defects, it is possible to reduce equipment costs and processes for annealing treatment, which was conventionally performed as bubble generation, and it is possible to reduce the total cost as a painted molded product.

1 (a) is a plan view of a flat plate test piece used for a paintability test, and FIG. 1 (b) is a cross-sectional view taken along the line AA of the flat plate test piece shown in FIG. 1 (a).

Hereinafter, the thermoplastic resin composition of the present invention and a molded product thereof will be specifically described.
The polycarbonate resin (A) used in the present invention is a resin having a repeating structural unit represented by the following general formula (1). n is the number of repeating units.

The polycarbonate resin (A) is obtained by reacting an aromatic dihydroxy compound with a carbonate precursor.

Examples of the aromatic dihydroxy compound include 2,2-bis (4-hydroxyphenyl) propane (hereinafter, may be referred to as “bisphenol A”), 1,1-bis (4-hydroxyphenyl) ethane, 2, 2-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) octane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 1,1-bis (3-tert) -Butyl-4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis (3-phenyl-4-hydroxyphenyl) propane, 2,2- Bis (hydroxyaryl) alkanes exemplified by bis (3-cyclohexyl-4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, bis (4-hydroxyphenyl) diphenylmethane and the like. With 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, etc. Exemplified bis (hydroxyaryl) cycloalkanes; cardo structure-containing bisphenols exemplified by 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (4-hydroxy-3-methylphenyl) fluorene and the like. Classes; dihydroxydiaryl ethers exemplified by 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether, etc .; 4,4'-dihydroxydiphenylsulfide, 4,4'-dihydroxy- Dihydroxydiaryl sulfides exemplified by 3,3'-dimethyldiphenyl sulfide and the like; dihydroxydiaryl sulfoxide exemplified by 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide and the like. Classes; dihydroxydiaryl sulfones exemplified by 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone and the like; hydroquinone, resorcin, 4,4'-dihydroxydiphenyl and the like. Be done.

Of these, bis (hydroxyaryl) alkanes are preferred, and bisphenol A is particularly preferred. These aromatic dihydroxy compounds may be used alone or in combination of two or more and copolymerized.

As the carbonate precursor to react with the aromatic dihydroxy compound, carbonyl halide, carbonate ester, haloformate and the like are used, and specifically, phosgene; diaryl carbonates such as diphenyl carbonate and ditril carbonate; dimethyl carbonate, diethyl carbonate and the like. Dialkyl carbonates; examples include dihaloformates of divalent phenols. Of these, phosgene is often preferably used. These carbonate precursors may also be used alone or in combination of two or more.

The method for producing the polycarbonate resin (A) used in the present invention is not particularly limited, and the polycarbonate resin (A) can be produced by a conventionally known method. Examples of the production method include an interfacial polymerization method (phosgen method), a melt transesterification method, a solution polymerization method (pyridine method), a ring-opening polymerization method for a cyclic carbonate compound, and a solid phase transesterification method for a prepolymer.

As a typical production method, a production method by an interfacial polymerization method is exemplified. In the presence of an organic solvent that is inert to the reaction and an alkaline aqueous solution, the pH is usually kept at 9 or higher to prevent the oxidation of aromatic dihydroxy compounds and, if necessary, molecular weight modifiers (terminating agents) and aromatic dihydroxy compounds. After reacting with phosgen using an antioxidant for this purpose, a polymerization catalyst such as a tertiary amine or a quaternary ammonium salt is added, and a polycarbonate resin is obtained by performing interfacial polymerization. The addition of the molecular weight modifier is not particularly limited as long as it is between the time of phosgenation and the time of the start of the polymerization reaction. The reaction temperature is, for example, 0 to 40 ° C., and the reaction time is, for example, 2 to 5 hours.

Here, the organic solvent applicable to the interfacial polymerization is not particularly limited as long as it is inert to the interfacial polymerization reaction, does not mix with water, and can dissolve the polycarbonate resin. Examples thereof include chlorinated hydrocarbons such as dichloromethane, 1,2-dichloroethane, tetrachloroethane, chloroform, monochlorobenzene and dichlorobenzene, and aromatic hydrocarbons such as benzene, toluene and xylene. Examples of the alkaline compound used in the alkaline aqueous solution include hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide.

Examples of the molecular weight modifier include compounds having a monovalent phenolic hydroxyl group and phenylchloroformates. Examples of the compound having a monovalent phenolic hydroxyl group include m-methylphenol, p-methylphenol, m-propylphenol, p-propylphenol, p-tert-butylphenol and p-long chain alkyl substituted phenol. The amount of the molecular weight modifier used is preferably 0.1 to 1 mol with respect to 100 mol of the aromatic dihydroxy compound.
As the polymerization catalyst, tertiary amines such as trimethylamine, triethylamine, tributylamine, tripropylamine, trihexylamine, pyridine; trimethylbenzylammonium chloride, tetrabutylammonium chloride, tetramethylammonium chloride, triethylbenzylammonium chloride, tri Examples thereof include quaternary ammonium salts such as octylmethylammonium chloride.

In the thermoplastic resin composition of the present invention, the blending amount of the polycarbonate resin (A) is in the range of 50 to 70 parts by weight. Impact resistance and heat resistance are improved by setting the blending amount of the polycarbonate resin (A) to 50 parts by weight or more, while by setting the blending amount to 70 parts by weight or less, the fluidity is not impaired and the moldability is improved. Excellent.

In the present invention, the viscosity average molecular weight (Mv) of the polycarbonate resin (A) is not particularly limited, but is preferably 15,000 or more and 26,000 or less, more preferably 16,000 or more and 25,000 or less. .. When Mv is 15,000 or more, mechanical properties such as impact resistance and heat resistance are improved, while when Mv is 26,000 or less, fluidity is excellent and moldability is improved.

In the present specification, the viscosity average molecular weight (Mv) of the polycarbonate resin (A) can be determined by the following method. First, the specific viscosity (ηSP) calculated by the following formula from a solution (concentration c = 0.7) in which 0.7 g of the polycarbonate resin (A) is dissolved in 100 ml of methylene chloride at 20 ° C. using an Ostwald viscometer. Ask for.
Specific viscosity (η _SP ) = (t-t ₀ ) / t ₀
[T ₀ is the number of seconds for methylene chloride to fall, and t is the number of seconds for the sample solution to fall]
Subsequently, the viscosity average molecular weight Mv can be calculated from the obtained specific viscosity (η _{SP) by the following Schnell's formula.}
η _SP / c = [η] +0.45 × ^{[η] 2} c (however, [η] is the ultimate viscosity)
[Η] = 1.23 × 10 ^-4 Mv ^0.83

The rubbery-containing graft copolymer (B) used in the present invention is at least an aromatic vinyl-based monomer (b) and cyanide in the presence of 40 to 65% by weight of the diene-based rubbery polymer (a). It is obtained by graft-copolymerizing 35 to 60% by weight of a monomer mixture containing a vinyl compound-based monomer (c). By containing the rubber-containing graft copolymer (B), the impact resistance of the molded product can be improved. The rubber-containing graft copolymer (B) referred to here includes a copolymer obtained by graft-copolymerizing a monomer mixture with a rubber polymer and a copolymer of an ungrafted vinyl-based monomer mixture. But it may be. The copolymer of such ungrafted vinyl-based monomer mixture is soluble in acetone.

Examples of the diene-based rubbery polymer (a) constituting the rubbery-containing graft copolymer (B) include polybutadiene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, and block copolymer of styrene-butadiene. Examples include coalescing and butyl-butadiene copolymers acrylate. These may be used alone or two or more kinds may be used.

The glass transition temperature of the diene-based rubbery polymer (a) is preferably 0 ° C. or lower, and the lower limit thereof is practically about −80 ° C. In the present invention, polybutadiene is preferably used as the diene-based rubbery polymer (a) from the viewpoint of impact resistance.

The weight average particle size of the diene-based rubbery polymer (a) is not particularly limited, but is preferably 0.10 μm or more, more preferably 0.15 μm or more, from the viewpoint of further improving the impact resistance of the molded product. Here, the weight average particle size can be measured by a particle size distribution measuring device by a laser diffraction / scattering method obtained by diluting the latex of a rubbery polymer with pure water 300 to 500 times.

The weight fraction of the diene-based rubbery polymer (a) constituting the rubbery-containing graft copolymer (B) is preferably adjusted in the range of 40 to 65% by weight. Impact resistance is improved by setting the weight fraction of the rubbery polymer to 40% by weight or more, while heat resistance is improved by setting it to 65% by weight or less.

Examples of the aromatic vinyl-based monomer (b) constituting the rubbery-containing graft copolymer (B) include styrene, vinyltoluene, o-ethylstyrene, p-methylstyrene, chlorostyrene and bromostyrene. Can be mentioned. These may be used alone or two or more kinds may be used. In the present specification, the aromatic vinyl-based monomer (b) does not contain α-methylstyrene. Styrene is preferably used from the viewpoint of further improving the fluidity during molding.

The weight fraction of the aromatic vinyl-based monomer (b) in the rubbery-containing graft copolymer (B) is preferably 26 to 43% by weight. Coloring can be suppressed by setting the weight fraction of the aromatic vinyl-based monomer (b) to 26% by weight or more, while graft polymerization is likely to proceed and the graft ratio is improved by setting it to 43% by weight or less. , Impact resistance is improved.

Examples of the vinyl cyanide-based monomer (c) constituting the rubbery-containing graft copolymer (B) include acrylonitrile, methacrylonitrile, and etacrylonitrile. Two or more of these may be used. In particular, acrylonitrile is preferably used from the viewpoint of impact resistance.

The weight fraction of the vinyl cyanide-based monomer (c) in the rubbery-containing graft copolymer (B) is preferably 9 to 17% by weight. By setting the weight fraction of the vinyl cyanide-based monomer (c) to 9% by weight or more, graft polymerization can easily proceed, the graft ratio can be improved, and the impact resistance can be improved, while 17% by weight or less. By doing so, coloring can be suppressed.

Further, as the rubber-containing graft copolymer (B) in the present invention, another copolymerizable monomer may be used to the extent that the effect of the present invention is not lost. Examples of other copolymerizable monomers include N-phenylmaleimide, N-methylmaleimide, and methyl methacrylate, which can be selected according to their respective purposes. These can be used alone or in plurals. If there is an intention to improve heat resistance and flame retardancy, N-phenylmaleimide is preferable. Further, for the purpose of improving hardness, methyl methacrylate is preferably used.

The graft ratio of the rubber-containing graft copolymer (B) is not particularly limited, but the graft ratio is preferably 7 to 40%, more preferably 20 to 28%, still more preferably, from the viewpoint of the balance between impact resistance and heat resistance. Is 22-26%. The graft ratio (%) of the rubber-containing graft copolymer (B) is represented by the following formula.

Graft rate (%) = {[Amount of copolymer graft-polymerized on rubber polymer] / [Rubber content of rubber-containing graft copolymer]} x 100

In the thermoplastic resin composition of the present invention, the blending amount of the rubbery-containing graft copolymer (B) is preferably in the range of 10 to 30 parts by weight. Impact resistance is improved by adding 10 parts by weight or more of the rubber-containing graft copolymer (B), while fluidity and heat resistance are improved by adding 30 parts by weight or less. do.

The vinyl-based copolymer (C) used in the present invention is a copolymer obtained by copolymerizing an aromatic vinyl-based monomer and a cyanide vinyl-based monomer.

The aromatic vinyl-based monomer constituting the vinyl-based copolymer (C) is styrene, similarly to the aromatic vinyl-based monomer (b) in the rubbery-containing graft copolymer (B) described above. , Α-Methylstyrene, vinyltoluene, o-ethylstyrene, p-methylstyrene, chlorostyrene, bromostyrene and the like. These may be used alone or in combination of two or more. Of these, styrene is particularly preferably adopted from the viewpoint of fluidity during molding.

The vinyl cyanide-based monomer constituting the vinyl-based copolymer (C) is, for example, the same as the vinyl cyanide-based monomer (c) in the rubbery-containing graft copolymer (B) described above. , Acrylonitrile, methacrylonitrile, etacrylonitrile and the like. These may be used alone or in combination of two or more. Of these, acrylonitrile is particularly preferably adopted from the viewpoint of impact resistance.

In addition to the above, other copolymerizable monomers may be used for the vinyl-based copolymer (C) to the extent that the effects of the present invention are not lost. Examples of the other copolymerizable monomer include those exemplified as other copolymerizable monomers constituting the rubbery-containing graft copolymer (B) described above.

The weight average molecular weight of the vinyl-based copolymer (C) used in the present invention is preferably 130,000 to 340,000, more preferably 150,000 to 320,000. Further, two or more kinds of vinyl-based copolymers having different molecular weights may be combined. By setting the weight average molecular weight of the vinyl-based copolymer to 130,000 or more, defective foam coating can be suppressed, and by setting it to 340,000 or less, the moldability is improved without impairing the fluidity.

Further, the content of the vinyl cyanide-based monomer contained in the vinyl-based copolymer (C) can have a composition distribution, and the composition distribution may be sharp or broad. The average vinyl cyanide content in the entire composition is preferably 22 to 42% by weight, more preferably 24 to 40% by weight, and particularly preferably 25 to 40% by weight. By setting the average vinyl cyanide content of the vinyl-based copolymer (C) to 22% by weight or more, defective foam coating can be suppressed, and by setting it to 42% by weight or less, the phase with the polycarbonate resin (A) can be suppressed. Impact resistance is improved without impairing solubility.
The average vinyl cyanide content means the vinyl cyanide content of the entire vinyl-based copolymer (C) having a composition distribution, and can be calculated by the following method.
Each 1 g of the vinyl-based copolymer (C) is formed into a film of about 40 μm by a heating press and analyzed by a Fourier transform infrared spectrophotometer (“FT / IR4100” manufactured by Nippon Kogaku Co., Ltd.). The composition of the vinyl-based copolymer (C) can be determined from the peak height ratio. The correspondence between each structural unit and the peak is as follows.
Structural unit derived from styrene: 1605 cm ^-1 peak attributed to the vibration of the benzene nucleus.
Structural unit derived from acrylonitrile: 2240 cm- ¹ peak attributed to -C≡N expansion and contraction.

In the thermoplastic resin composition of the present invention, the blending amount of the vinyl-based copolymer (C) is in the range of 10 to 30 parts by weight. When the blending amount of the vinyl-based copolymer (C) is 10 parts by weight or more, the coatability is improved, while when the blending amount is 30 parts by weight or less, the impact resistance and fluidity are improved.

In the present invention, as a method for producing the rubbery-containing graft copolymer (B) and the vinyl-based copolymer (C), for example, bulk polymerization, suspension polymerization, bulk suspension polymerization, solution polymerization, emulsification polymerization, precipitation Polymerization methods such as polymerization may be mentioned, and two or more of these may be combined. The method for charging the monomers constituting each copolymer is not particularly limited, and the monomers may be charged all at once at the initial stage, or the number of monomers may be adjusted in order to adjust the composition distribution of the copolymer to a desired range. It may be prepared in batches.

In the present invention, an ethylene / acrylic acid ester is further added as an elastomer component (D) to a total of 100 parts by weight of the polycarbonate resin (A), the rubbery-containing graft copolymer (B) and the vinyl-based copolymer (C). / Contains at least one selected from maleic anhydride copolymer (D-1), ethylene / glycidyl methacrylate copolymer (excluding graft copolymer) (D-2), and polyester elastomer (D-3). It is characterized by doing.

Examples of ethylene / acrylic acid ester / maleic anhydride copolymer (D-1) include ethylene / ethyl acrylate / maleic anhydride copolymer, ethylene / methyl acrylate / maleic anhydride copolymer, ethylene / Examples thereof include butyl acrylate / maleic anhydride copolymers. Among these, ethylene / methyl acrylate / maleic anhydride copolymer and ethylene / ethyl acrylate / maleic anhydride copolymer are preferable from the viewpoint of suppressing defective bubble coating. In addition, these copolymers may be used alone or in combination of two or more.

Examples of the ethylene / glycidyl methacrylate copolymer (excluding the graft copolymer) (D-2) include ethylene / glycidyl methacrylate copolymer, ethylene / glycidyl methacrylate / vinyl acetate copolymer, and ethylene / methacryl. Examples thereof include acid glycidyl / acrylic acid ester copolymer, ethylene / glycidyl acrylate / vinyl acetate copolymer and the like. Among these, ethylene / glycidyl methacrylate copolymer and ethylene / glycidyl methacrylate / acrylic acid ester copolymer are preferable from the viewpoint of suppressing defective foam coating. In addition, these copolymers may be used alone or in combination of two or more.

The polyester elastomer (D-3) is a polyether ester block copolymer or a polyester ester block copolymer having an aromatic polyester as a hard segment and a poly (alkylene oxide) glycol and / or an aliphatic polyester as a soft segment. , Polyester ester / ester block copolymers. Here, the aromatic polyester constituting the hard segment is a polymer obtained by polycondensing a dicarboxylic acid component and a diol component, which are usually 60 mol% or more, which are terephthalic acid components.

Specific examples of the aromatic polyester component include polyethylene terephthalate, polybutylene terephthalate, polyethylene (terephthalate / isophthalate), polybutylene (terephthalate / isophthalate) and the like.
Specific examples of the poly (alkylene oxide) glycol and the aliphatic polyester constituting the soft segment here include polyethylene glycol, poly (1,2- and 1,3-propylene oxide) glycol, and poly (tetramethylene oxide). Glycol, a copolymer of ethylene oxide and propylene oxide, a copolymer of ethylene oxide and hydrofuran, polyethylene adipate, polybutylene adipate, poly-ε-caprolactone, polyethylene sebacate, polybutylene sebacate and the like are preferable.

The ratio of the polyester hard segment to the soft segment of the polyester elastomer is preferably 95/5 to 10/90, particularly 90/10 to 30/70 by weight.

Specific examples of the polyester elastomer resin include polyethylene terephthalate poly (tetramethylene oxide) glycol block copolymer, polyethylene terephthalate / isophthalate poly (tetramethylene oxide) glycol block copolymer, and polybutylene terephthalate poly (tetramethylene oxide). Oxide) Glycol block copolymer, polybutylene terephthalate / isophthalate poly (tetramethylene oxide) glycol block copolymer, polybutylene terephthalate / decandicarboxylate poly (tetramethylene oxide) glycol block copolymer, polybutylene Telephthalate poly (propylene oxide / ethylene oxide) glycol block copolymer, polybutylene terephthalate / isophthalate poly (propylene oxide / ethylene oxide) glycol block copolymer, polybutylene terephthalate / decandicarboxylate poly (propylene oxide / ethylene oxide) ) Glycol block copolymer, polybutylene terephthalate poly (ethylene oxide) glycol block copolymer and the like are preferably mentioned.

Among these polyester elastomer resins, polybutylene terephthalate / poly (tetramethylene oxide) glycol block copolymer, polybutylene terephthalate / isophthalate / poly (tetramethylene oxide) glycol, in particular, from the viewpoint of suppressing bubble-like coating defects. Block copolymers are preferably used.

In the thermoplastic resin composition of the present invention, the blending amount of the elastomer component (D) is a total of 100 weights of the polycarbonate resin (A), the rubbery-containing graft copolymer (B), and the vinyl-based copolymer (C). It is in the range of 1 to 5 parts by weight with respect to the part. By setting the blending amount of the elastomer component (D) to 1 part by weight or more, defective foam coating can be suppressed, and by setting it to 5 parts by weight or less, heat resistance is improved.

The thermoplastic resin composition of the present invention includes other thermoplastic resins such as nylon resin and polyester resin, hindered phenol-based, sulfur-containing organic compound-based, and phosphorus-containing organic compound-based, as long as the effects of the present invention are not impaired. Antioxidants such as antioxidants, heat stabilizers such as phenols and acrylates, UV absorbers such as benzotriazoles, benzophenones and salicylates, light stabilizers such as organic nickels and hindered amines, plasticizers, lubricants and drips. Liquids such as inhibitors, mold release agents, antistatic agents, pigments and dyes, water and silicone oils, and liquid paraffins can also be blended.

Further, various fillers can be blended.
Examples of the filler include those having a fibrous, plate-like, powder-like, and granular shape, and any of them may be used in the present invention. Specifically, polyacrylonitrile (PAN) -based and pitch-based carbon fibers, stainless fibers, metal fibers such as aluminum fibers and brass fibers, organic fibers such as aromatic polyamide fibers, gypsum fibers, ceramic fibers, asbestos fibers, and zirconia. Fibrous or whisker-like fillers such as fiber, alumina fiber, silica fiber, titanium oxide fiber, silicon carbide fiber, glass fiber, rock wool, potassium titanate whisker, barium titanate whisker, aluminum borate whisker, silicon nitride whisker, etc. Powders such as mica, talc, kaolin, silica, calcium carbonate, glass flakes, glass beads, glass microballoons, clay, molybdenum disulfide, wallastenite, montmorillonite, titanium oxide, zinc oxide, barium sulfate, calcium polyphosphate, graphite, etc. Granular or plate-shaped fillers and the like can be mentioned. These may be used alone or two or more kinds may be used.

The thermoplastic resin composition can be obtained by melting and mixing each of the constituent resin components. The melt-mixing method is not particularly limited, but a method of melt-mixing using a heating device, a cylinder having a vent, and a single-screw or biaxial screw can be adopted. The heating temperature at the time of melting and mixing is preferably selected from the temperature range of 230 to 300 ° C., but the temperature gradient at the time of melting and mixing can be freely set within a range that does not impair the object of the present invention. be. Further, when a biaxial screw is used, it may be in the same rotation direction or in different rotation directions.

The thermoplastic resin composition of the present invention can be molded by a known method such as injection molding, extrusion molding, blow molding, vacuum molding, compression molding, gas assist molding and the like. Although not particularly limited, it is preferably molded by injection molding. The cylinder temperature during injection molding is preferably in the temperature range of 230 to 270 ° C, and the mold temperature is preferably in the temperature range of 30 to 80 ° C.

By applying a coating to the surface of the obtained molded product, a coated molded product having a coating layer can be obtained. This painted molded product suppresses the generation of air bubbles during painting and has an excellent painted appearance.

According to the thermoplastic resin composition of the present invention, it is possible to obtain a molded product having excellent mechanical properties and heat resistance and capable of suppressing the occurrence of bubble-like coating defects. It can be suitably used for painting parts such as automobile parts. In particular, it is extremely useful for painting interior parts such as instrument panels, center consoles, center clusters, and navigation panels, which are automobile parts, and exterior parts such as rear spoilers, garnishes, and roof rails.

In order to explain the present invention more specifically, examples are given below, but these examples do not limit the present invention in any way. Here, unless otherwise specified, "%" represents% by weight, and "part" represents parts by weight.

First, the evaluation methods in each Example and Comparative Example will be described below.
(1) Weight average particle size of rubbery polymer The weight average particle size of rubbery polymer is obtained by diluting and dispersing the rubbery polymer with an aqueous medium, and using a laser scattering diffraction method particle size distribution measuring device “LS 13 320” ( The volume average particle size was measured by Beckman Coulter Co., Ltd.).

(2) Graft rate of rubber-containing graft copolymer (B) 200 ml of acetone is added to a predetermined amount (m; about 1 g) of the rubber-containing graft copolymer, and reflux is carried out in a hot water bath at a temperature of 70 ° C. for 3 hours. did. The solution was centrifuged at 8800 r / m (10000 G) for 40 minutes and then the insoluble material was filtered. This insoluble matter was dried under reduced pressure at a temperature of 60 ° C. for 5 hours, and its 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) x L)] / [(m) x L]} x 100

(3) Weight average molecular weight of vinyl-based copolymer (C) For the vinyl-based copolymer obtained in each reference example, a differential refractometer was used as a detector using a gel permeation chromatography (GPC) apparatus manufactured by Water. (Water2414), using Polymer Laboratories MIXED-B (2 bottles) as the column, and acetone as the distillate, the weight average molecular weight in terms of polystyrene (PS) under the conditions of a flow velocity of 1 ml / min and a column temperature of 40 ° C. It was measured.

(4) Average vinyl cyanide content in the vinyl-based copolymer (C) 1 g of the vinyl-based copolymer (C) obtained in each reference example is formed into a film of about 40 μm by a heating press, and Fourier-converted infrared spectroscopy is performed. The average vinyl chloride content was determined from the ratio of the heights of each peak appearing in the chart obtained by analysis with a photometric meter (manufactured by Nippon Kogaku Co., Ltd., "FT / IR4100"). The correspondence between each structural unit and the peak is as follows.
Structural unit derived from styrene: 1605 cm ^-1 peak attributed to the vibration of the benzene nucleus.
Structural unit derived from acrylonitrile: 2240 cm- ¹ peak attributed to -C≡N expansion and contraction.

(5) Liquidity (melt flow rate (MFR))
MFR was measured according to ISO1133 (2011) (temperature: 240 ° C., load: 98N).
If the MFR is 20 g / 10 minutes or more, the fluidity is good.

(6) Heat resistance Thermal deformation temperature: Measured in accordance with ISO75-2 (2013) (measured under 1.8 MPa conditions). The test piece was obtained by molding a multipurpose test piece type A1 specified in JIS K 7139 (2009) using an injection molding machine in which the cylinder temperature was set to 250 ° C. and the mold temperature was set to 60 ° C.
When the thermal deformation temperature is 100 ° C. or higher, the heat resistance is good.

(7) Impact resistance A multipurpose test specified in JIS K 7139 using an injection molding machine in which the cylinder temperature is set to 250 ° C and the mold temperature is set to 60 ° C from the pellets obtained in each Example and Comparative Example. The Charpy impact strength was measured in accordance with ISO179 / 1eA (2012) using a type B2 test piece obtained by molding a piece type A1 and cutting it out.
When the Charpy impact strength is 35 kJ / m ² or more, the impact resistance is good.

(8) Paintability (poor bubble coating of molded products with edges)
A flat plate test piece having a width of 70 mm, a length of 150 mm, and a thickness of 3 mm, which is schematically shown in FIGS. 1 (a) and 1 (b) and has edges at an angle of 45 ° at both ends in the longitudinal direction, was used (FIG. 1 (a)). Is a plan view of the flat plate test piece, and FIG. 1 (b) is a cross-sectional view taken along the line AA of the flat plate test piece). A two-component acrylic urethane resin paint (urethane PG60, manufactured by Kansai Paint Co., Ltd.) was applied to one side of the flat plate test piece using a spray gun with a coating film thickness of 30 μm, and then 30 with a hot air dryer set at a temperature of 80 ° C. Allowed to dry for minutes. The number of air bubbles generated on the surface of the coated molded product after drying was counted, and a score of 1 point (poor) to 5 points (excellent) was given according to the following index. It should be noted that 2 points or less are practically at a level at which it can be judged that painting without measures against bubble generation such as annealing is impossible.
5 points: No bubbles generated (excellent)
4 points: 1 to 10 bubbles generated (good)
3 points: The number of bubbles generated is 11 to 30 (possible)
2 points: The number of bubbles generated is 31 to 100 (impossible)
1 point: The number of bubbles generated is 100 or more (impossible)

Next, the raw materials used in each Example and Comparative Example are shown below.
(Reference Example 1) Polycarbonate resin (A)
(A-1) "Taflon" A1700 (Mv = 17,000) manufactured by Idemitsu Kosan Co., Ltd.

(Reference Example 2) [Production of rubber-containing graft copolymer (B)]
(B-1) Polybutadiene latex (a mixture of polybutadiene latex having a weight average particle size of 350 nm and polybutadiene latex having a weight average particle size of 800 nm at a mass ratio of 8: 2) Styrene in the presence of 45% by weight (solid content equivalent) A monomer mixture consisting of 40% by weight and 15% by weight of acrylonitrile was emulsion-polymerized using potassium stearate to obtain a rubber-reinforced styrene resin latex. This was added to a 0.3 wt% dilute sulfuric acid aqueous solution at 90 ° C. to aggregate it, then neutralized with a sodium hydroxide aqueous solution, washed, dehydrated and dried, and then a rubbery graft copolymer (a rubbery-containing graft copolymer (). B-1) was prepared. The graft ratio was 25% by weight.

(Reference Example 3) [Manufacturing of vinyl-based copolymer (C)]
(C-1) A 0.05% by weight methyl methacrylate / acrylamide copolymer in a stainless steel autoclave having a capacity of 20 L and equipped with a baffle and a Faudra-type stirring blade (described in Japanese Patent Publication No. 45-24151). Was dissolved in 165% by weight of ion-exchanged water, and the solution was stirred at 400 rpm, and the inside of the system was replaced with nitrogen gas. Next, a mixed solution of 33% by weight of acrylonitrile, 67% by weight of styrene, 0.22% by weight of t-dodecyl mercaptan, and 0.30% by weight of 2,2'-azobisisobutylnitrile was added while stirring in the reaction system. , The copolymerization reaction was started at 70 ° C. A vinyl-based copolymer (C-1) is prepared by raising the temperature to 100 ° C. over 3 hours from the start of the copolymerization, holding it for 30 minutes, and then washing, dehydrating, and drying the slurry obtained by cooling. did. The weight average molecular weight of the vinyl-based copolymer (C-1) measured with an acetone solvent (temperature 40 ° C.) was 200,000. The average vinyl cyanide content was 30.5% by weight.
(C-2) A vinyl-based copolymer (C-1) by the same process as the vinyl-based copolymer (C-1) except that acrylonitrile is 27% by weight, styrene is 73% by weight, and t-dodecyl mercaptan is 0.25% by weight. C-2) was prepared. The weight average molecular weight of the vinyl-based copolymer (C-2) measured with an acetone solvent (temperature 40 ° C.) was 150,000, and the average vinyl cyanide content was 25.4% by weight.
(C-3) A vinyl-based copolymer (C-1) by the same process as the vinyl-based copolymer (C-1) except that acrylonitrile is 45% by weight, styrene is 55% by weight, and t-dodecyl mercaptan is 0.25% by weight. C-3) was prepared. The weight average molecular weight of the vinyl-based copolymer (C-3) measured with an acetone solvent (temperature 40 ° C.) was 150,000, and the average vinyl cyanide content was 40.0% by weight.
(C-4) A vinyl-based copolymer (C-1) by the same process as the vinyl-based copolymer (C-1) except that acrylonitrile is 27% by weight, styrene is 73% by weight, and t-dodecyl mercaptan is 0.15% by weight. C-4) was prepared. The weight average molecular weight of the vinyl-based copolymer (C-4) measured with an acetone solvent (temperature 40 ° C.) was 320,000, and the average vinyl cyanide content was 25.5% by weight.
(C-5) A vinyl-based copolymer (C-1) by the same process as the vinyl-based copolymer (C-1) except that acrylonitrile is 45% by weight, styrene is 55% by weight, and t-dodecyl mercaptan is 0.15% by weight. C-5) was prepared. The weight average molecular weight of the vinyl-based copolymer (C-5) measured with an acetone solvent (temperature 40 ° C.) was 320,000, and the average vinyl cyanide content was 40.7% by weight.
(C-6) A vinyl-based copolymer (C-1) by the same process as the vinyl-based copolymer (C-1) except that acrylonitrile is 27% by weight, styrene is 73% by weight, and t-dodecyl mercaptan is 0.30% by weight. C-6) was prepared. The weight average molecular weight of the vinyl-based copolymer (C-6) measured with an acetone solvent (temperature 40 ° C.) was 130,000, and the average vinyl cyanide content was 25.4% by weight.
(C-7) A vinyl-based copolymer (C-1) by the same process as the vinyl-based copolymer (C-1) except that acrylonitrile is 24% by weight, styrene is 76% by weight, and t-dodecyl mercaptan is 0.25% by weight. C-7) was prepared. The weight average molecular weight of the vinyl-based copolymer (C-7) measured with an acetone solvent (temperature 40 ° C.) was 150,000, and the average vinyl cyanide content was 24.0% by weight.
(C-8) A vinyl-based copolymer (C-1) by the same process as the vinyl-based copolymer (C-1) except that acrylonitrile is 27% by weight, styrene is 73% by weight, and t-dodecyl mercaptan is 0.010% by weight. C-8) was prepared. The weight average molecular weight of the vinyl-based copolymer (C-8) measured with an acetone solvent (temperature 40 ° C.) was 340,000, and the average vinyl cyanide content was 25.4% by weight.
(C-9) A vinyl-based copolymer (C-1) by the same process as the vinyl-based copolymer (C-1) except that acrylonitrile is 45% by weight, styrene is 55% by weight, and t-dodecyl mercaptan is 0.25% by weight. C-9) was prepared. The weight average molecular weight of the vinyl-based copolymer (C-9) measured with an acetone solvent (temperature 40 ° C.) was 150,000, and the average vinyl cyanide content was 40.7% by weight.

(Reference Example 4) [Elastomer component (D)]
(D-1) "Rotader" 4613 manufactured by Arkema Co., Ltd. (ethylene / methyl acrylate / maleic anhydride copolymer)
(D-2) "Rotader" AX8900 manufactured by Arkema Co., Ltd. (ethylene / glycidyl methacrylate / methyl acrylate copolymer)
(D-3) "Hitrel" 2401 (polyester elastomer) manufactured by Toray DuPont Co., Ltd.

Hereinafter, Examples and Comparative Examples will be described.
(Examples 1 to 9, 11 to 21, Comparative Examples 1 to 9 , Reference Example 5 )
The polycarbonate resin (A), the rubber-containing graft copolymer (B), the vinyl-based copolymer (C), and the ethylene / acrylic acid ester / anhydrous maleic acid copolymer (D-1) as the elastomer component (D). , Ethylene / glycidyl methacrylate copolymer (D-2) and polyester elastomer (D-3) are blended in parts by weight shown in Tables 1, 2 and 3 and further manufactured by ADEKA Co., Ltd. as an antioxidant. 0.1 part by weight of "Adecasterb" 135A was added and mixed at 23 ° C. using a Henchel mixer. The obtained mixture was melt-kneaded at a cylinder set temperature of 250 ° C. using a twin-screw extruder with a vent having a screw diameter of 30 mm (PCM30 manufactured by Ikekai Co., Ltd.) to obtain pellets of a thermoplastic resin composition.
After the pellets of the obtained thermoplastic resin composition are dried in a box-shaped hot air dryer set at 100 ° C. for 3 hours or more, various types are used at a cylinder temperature of 250 ° C. and a mold temperature of 60 ° C. using an injection molding machine. Specimens were prepared and various evaluations were carried out. The results of Examples and Reference Examples are shown in Tables 1 and 2, and the results of Comparative Examples are shown in Table 3.

From the evaluation results of Tables 1 and 2, the thermoplastic resin compositions of the present invention (Examples 1 to 9, 11 to 21) are all excellent in fluidity, heat resistance, impact resistance and coating property. I understand.

On the other hand, in Comparative Example 1, since the amount of the polycarbonate resin (A) is small, the heat resistance and impact resistance are low, and in Comparative Example 2, since the amount of the polycarbonate resin (A) is too large, the fluidity is low and molding is performed. Bad sex. Comparative Example 3 has a low impact resistance because the amount of the rubber-containing graft copolymer (B) is small, and Comparative Example 4 has a large amount of the rubber-containing graft copolymer (B), so that it has heat resistance. Is low. In Comparative Example 5, since the blending amount of the vinyl-based copolymer (C) is small, the fluidity and the coatability are low. Comparative Example 6 is inferior in coatability because the ethylene / glycidyl methacrylate copolymer (excluding the graft copolymer) (D-2), which is the elastomer component (D), is not blended. Comparative Examples 7 to 9 have low heat resistance because the amount of the elastomer component (D-1 to D-3) is too large.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. This application is based on a Japanese patent application filed on March 29, 2019 (Japanese Patent Application No. 2019-68395), the contents of which are incorporated herein by reference.

The thermoplastic resin composition of the present invention can obtain a thermoplastic resin composition and a molded product which are excellent in mechanical properties and heat resistance and can significantly suppress the generation of bubbles during painting. Taking advantage of these characteristics, it can be suitably used for painted parts such as automobile exteriors and interiors.

Claims (5)

50 to 70 parts by weight of polycarbonate resin (A),
Diene-based rubbery polymer (a) A monomer mixture containing at least an aromatic vinyl-based monomer (b) and a vinyl cyanide-based monomer (c) in the presence of 40 to 65% by weight of a monomer mixture 35- 10 to 30 parts by weight of the rubbery-containing graft copolymer (B) obtained by graft-copolymerizing 60% by weight.
It contains 10 to 30 parts by weight of a vinyl-based copolymer (C) obtained by copolymerizing an aromatic vinyl-based monomer and a cyanide vinyl-based monomer.
The weight average molecular weight of the vinyl-based copolymer (C) is in the range of 130,000 to 320,000.
The average vinyl cyanide content of the vinyl-based copolymer (C) is in the range of 22 to 42% by weight.
Ethylene / acrylic acid ester / maleic anhydride as the elastomer component (D) with respect to a total of 100 parts by weight of the polycarbonate resin (A), the rubbery graft copolymer (B) and the vinyl-based copolymer (C). 1 to 5 parts by weight of at least one selected from a copolymer (D-1), an ethylene / glycidyl methacrylate copolymer (excluding graft copolymers) (D-2), and a polyester elastomer (D-3). A thermoplastic resin composition comprising. The thermoplastic resin composition according to claim 1 , which is used for a molded product for coating. A molded article for painting comprising the thermoplastic resin composition according to claim 1 or 2. A painted molded product obtained by painting the molded product for painting according to claim 3. An automobile part comprising the thermoplastic resin composition according to claim 1 or 2.

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