JP2022115666A - Thermoplastic resin composition - Google Patents

Abstract

To provide a thermoplastic resin composition having an excellent balance between impact resistance, heat resistance, weather resistance, dimensional stability and thermal stability.SOLUTION: A thermoplastic resin composition contains a copolymer containing a polycarbonate resin, a graft copolymer whose resin pH is prescribed, a copolymer containing an aromatic vinyl-based monomer and a vinyl cyanide-based monomer, talc and a phosphate compound, which are contained in their respective amounts.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a thermoplastic resin composition having an excellent balance of impact resistance, heat resistance, weather resistance, dimensional stability and thermal stability.

Compositions composed of polycarbonate resins and ABS resins (hereinafter referred to as PC/ABS resins) are excellent in impact resistance, heat resistance, and moldability, and are used in vehicle parts, home appliances, and office equipment parts. It is used for various purposes such as In particular, there is a tendency for vehicle parts and the like to increase in size, and the shape tends to be more complicated in design. In addition, there is a tendency for molded products to be designed to be thinner in order to reduce vehicle weight. there is There are cases where PC/ABS resin is adopted as one of the options.

When glass fiber, carbon fiber, or the like is blended with PC/ABS resin to improve rigidity and dimensional stability, there is a problem that the impact resistance is lowered and the external appearance of the molded product is also deteriorated. On the other hand, when talc is blended, the appearance of the molded product is improved, but the thermal stability is lowered, and there is a problem that an appearance defect called silver occurs on the surface of the molded product during the injection molding process.

As a method for improving the thermal stability when talc is blended, for example, Patent Document 1 discloses a resin composition containing a polycarbonate resin, a graft polymer, talc and a phosphoric acid ester compound. 2 discloses a resin composition containing an aromatic polycarbonate resin as an essential component, a granular organic phosphoric acid ester compound-containing talc, and a rubbery polymer, and Patent Document 3 discloses an aromatic polycarbonate resin. , discloses a resin composition comprising an emulsion polymerized thermoplastic resin and an acidic phosphate ester having a defined structural formula.

However, in recent years, molding temperatures have tended to rise due to the trend toward larger molded parts, more complicated shape designs, and thinner parts due to lighter weight. not a thing

JP 2003-138122 A

JP 2010-229305 A

JP 2012-158737 A

An object of the present invention is to provide a thermoplastic resin composition having an excellent balance of impact resistance, heat resistance, weather resistance, dimensional stability and thermal stability.

As a result of intensive studies, the present inventors found that the above problems can be solved by containing specific amounts of polycarbonate resin, graft copolymer with resin pH regulation, copolymer, talc and phosphoric acid compound, and the present invention. Completed.

That is, the present invention consists of the following [1].
[1] Contains polycarbonate resin (A), graft copolymer (B), copolymer (C), talc (D) and phosphoric acid compound (E), and satisfies the following conditions (1) to (8) A thermoplastic resin composition.
(1) The content of the polycarbonate resin (A) is 40 to 80% by mass in the total 100% by mass of (A), (B), (C) and (D).
(2) The graft copolymer (B) is selected from the rubbery polymer (b-1), an aromatic vinyl-based monomer, a vinyl cyanide-based monomer, and a (meth)acrylic acid ester-based monomer. A graft copolymer obtained by graft polymerization with a monomer component (b-2) containing at least one of
(3) The graft copolymer (B) has a resin pH of 3 to 6.6.
(4) The content of the graft copolymer (B) is 5 to 45% by mass in the total 100% by mass of (A), (B), (C) and (D).
(5) Copolymer (C) is a copolymer obtained by polymerizing a monomer component containing an aromatic vinyl-based monomer and a vinyl cyanide-based monomer.
(6) The content of the copolymer (C) is 0 to 39% by mass in the total 100% by mass of (A), (B), (C) and (D).
(7) The content of talc (D) is 5 to 24% by mass in the total 100% by mass of (A), (B), (C) and (D).
(8) The content of the phosphoric acid compound (E) is 0.01 to 1.5 parts by mass per 100 parts by mass of (A), (B), (C) and (D).
[2] The thermoplastic resin according to [1], characterized by containing 3 to 13 parts by mass of a phosphate ester with respect to a total of 100 parts by mass of (A), (B), (C) and (D). Composition.

INDUSTRIAL APPLICABILITY The present invention can provide a thermoplastic resin composition having an excellent balance of impact resistance, heat resistance, weather resistance, dimensional stability and thermal stability.

Hereinafter, the present invention will be described in detail.

The thermoplastic resin composition of the present invention contains polycarbonate resin (A), graft copolymer (B), copolymer (C), talc (D) and phosphoric acid compound (E).

The polycarbonate resin (A) is a polymer obtained by a phosgene method in which various dihydroxydiaryl compounds are reacted with phosgene, or a transesterification method in which a dihydroxydiaryl compound is reacted with a carbonate such as diphenyl carbonate. These include polycarbonate resins made from 2,2-bis(4-hydroxyphenyl)propane; "bisphenol A."

Examples of the dihydroxydiaryl compounds include bisphenol A, bis(4-hydroxydiphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)butane, 2, 2-bis(4-hydroxyphenyl)octane, bis(4-hydroxyphenyl)diphenylmethane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 1,1-bis(4-hydroxy-3- 3-butylphenyl)propane, 2,2-bis(4-hydroxy-3-bromophenyl)propane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, 2,2-bis(4- bis(hydroxyaryl)alkanes such as hydroxy-3,5-dichlorophenyl)propane; bis(hydroxyphenyl)alkanes such as 1,1-bis(4-hydroxyphenyl)cyclopentane; (hydroxyaryl)cycloalkanes, dihydroxydiaryl ethers such as 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether, 4,4'-dihydroxydiphenyl sulfide, 4, dihydroxydiarylsulfides such as 4'-dihydroxy-3,3'-dimethyldiphenylsulfide, dihydroxydiarylsulfoxides such as 4,4'-dihydroxydiphenylsulfoxide, 4,4'-dihydroxydiphenylsulfone, 4, and dihydroxydiarylsulfones such as 4'-dihydroxy-3,3'-dimethyldiphenylsulfone.

These may be used alone or in combination of two or more. In addition to these, piperazine, dipiperidylhydroquinone, resorcinol, 4,4'-dihydroxydiphenyls and the like may be mixed.

Further, the above dihydroxydiaryl compound and a trihydric or higher phenolic compound as shown below may be used in combination. Examples of trihydric or higher phenols include phloroglucinol, 4,6-dimethyl-2,4,6-tri-(4-hydroxyphenyl)-heptene, 4,6-dimethyl-2,4,6-tri-(4 -hydroxyphenyl)-heptane, 1,3,5-tri-(4-hydroxyphenyl)benzol, 1,1,1-tri-(4-hydroxyphenyl)ethane and 2,2-bis-[4,4- bis(4-hydroxyphenyl)cyclohexyl]propane and the like. In producing these polycarbonate resins, the weight average molecular weight of the polycarbonate resin is usually 10,000 to 80,000, preferably 15,000 to 60,000. Molecular weight modifiers, catalysts and the like can be used as required. The weight average molecular weight can be measured by gel permeation chromatography (GPC) using polystyrene as a standard substance.

In the graft copolymer (B), the rubbery polymer (b-1) contains at least one selected from aromatic vinyl monomers, vinyl cyanide monomers and (meth)acrylic acid ester monomers. It is obtained by graft polymerization of the monomer component (b-2) containing one type.

The rubbery polymer (b-1) constituting the graft copolymer (B) is not particularly limited, and may be polybutadiene rubber, styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber ( NBR), ethylene-propylene rubber, ethylene-propylene rubber such as ethylene-propylene-nonconjugated diene (ethylidene norbornene, dicyclopentadiene, etc.) rubber, acrylic rubber such as polybutyl acrylate rubber, silicone One type or two or more types of system rubber can be used. The acrylic rubber also includes rubber having a core-shell structure. Examples of rubbers having a core-shell structure (described as core/shell) include conjugated diene rubber/acrylic rubber, silicone rubber/acrylic rubber, and hard polymer (having a glass transition temperature of 20° C. or higher)/acrylic rubber. etc. The hard polymer (having a glass transition temperature of 20° C. or higher) contains at least one selected from aromatic vinyl monomers, vinyl cyanide monomers, and (meth)acrylic acid ester monomers. Examples thereof include a polymer obtained by polymerizing a monomer to be used. Among the above, polybutadiene rubber, styrene-butadiene rubber, ethylene-propylene-diene rubber, conjugated diene rubber/acrylic rubber, silicone rubber/acrylic rubber, hard polymer (glass transition temperature of 20°C or higher)/acrylic Rubber is preferred. The glass transition temperature of the hard polymer can be calculated from the FOX formula.

The weight average particle size of the rubbery polymer (b-1) is not particularly limited, but is preferably 0.1 to 2.0 μm, more preferably 0.15 to 1.0 μm, from the viewpoint of impact resistance. It can also be adjusted by aggregating and enlarging a rubbery polymer having a weight average particle size of 0.05 to 0.3 μm.

The graft copolymer (B) is the rubbery polymer (b-1) described above and is selected from aromatic vinyl monomers, vinyl cyanide monomers and (meth)acrylic acid ester monomers. It is obtained by graft polymerizing a monomer component (b-2) containing at least one of

Examples of aromatic vinyl-based monomers for the monomer component (b-2) include styrene, α-methylstyrene, paramethylstyrene, bromostyrene and the like, and one or more of them can be used.

Examples of the vinyl cyanide-based monomer of the monomer component (b-2) include acrylonitrile, methacrylonitrile, ethacrylonitrile, fumaronitrile and the like, and one or more of them can be used.

Examples of the (meth)acrylic acid ester-based monomer of the monomer component (b-2) include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, and butyl (meth)acrylate. , 2-ethylhexyl acrylate, phenyl (meth)acrylate, 4-t-butylphenyl (meth)acrylate, (di)bromophenyl (meth)acrylate, chlorophenyl (meth)acrylate, and the like. A species or two or more species can be used.

The monomer component (b-2) includes other monomers copolymerizable with aromatic vinyl monomers, vinyl cyanide monomers and (meth)acrylic acid ester monomers. Maleimide-based monomers, amide-based monomers, unsaturated carboxylic acid-based monomers, polyfunctional monomers, etc. can be mentioned, and one or more of them can be used.

Examples of maleimide-based monomers include N-phenylmaleimide and N-cyclohexylmaleimide.

Amide-based monomers include acrylamide, methacrylamide, and the like.

Examples of unsaturated carboxylic acid monomers include (meth)acrylic acid, ethacrylic acid, maleic acid, fumaric acid, itaconic acid and crotonic acid.

Polyfunctional monomers include divinylbenzene, allyl (meth)acrylate, ethylene glycol di(meth)acrylate, diallyl phthalate, dicyclopentadiene di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol hexa (meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, triallyl cyanurate, triallyl isocyanurate and the like.

Although there is no particular limitation on the composition ratio of the above-mentioned monomers graft-polymerized to the rubbery polymer (b-1), 50 to 90% by mass of aromatic vinyl-based monomer and 10% by mass of vinyl cyanide-based monomer Composition ratio of up to 50% by mass and 0 to 40% by mass of other copolymerizable monomers, 0 to 50% by mass of aromatic vinyl monomers, and 50 to 100% by mass of (meth)acrylic acid ester monomers % and other copolymerizable vinyl monomers 0 to 50% by mass, aromatic vinyl monomers 20 to 70% by mass, (meth)acrylic acid ester monomers 20 to 70% by mass , 10 to 60% by mass of a vinyl cyanide monomer and 0 to 50% by mass of another copolymerizable monomer (the total monomers graft-polymerized to the rubbery polymer amount is 100% by mass).

The content of the rubbery polymer (b-1) in the graft copolymer (B) is preferably 20 to 80% by mass, more preferably 40 to 70% by mass, from the balance of physical properties such as impact resistance and fluidity. preferable.

The graft ratio of the graft copolymer (B) and the reduced viscosity of the acetone-soluble portion are not particularly limited, but from the viewpoint of the balance of physical properties such as impact resistance and fluidity, the graft ratio is preferably 20 to 150%. Preferably, 30 to 100% is more preferred, and 36 to 75% is particularly preferred. The reduced viscosity of the acetone-soluble portion is preferably 0.2 to 1.5 dl/g, more preferably 0.3 to 1.0 dl/g.

The graft ratio and the reduced viscosity of the acetone-soluble portion can be determined as follows.

Separation method About 2 g of the graft copolymer (B) and 60 ml of acetone were placed in an Erlenmeyer flask and immersed for 24 hours. After that, it is separated into a soluble part and an insoluble part by centrifuging at 15,000 rpm for 30 minutes using a centrifuge. The insoluble matter is obtained by vacuum drying at room temperature for a whole day and night. The soluble matter is obtained by precipitating the acetone-soluble portion in methanol and drying it at room temperature for a whole day and night by vacuum drying.
Graft rate
Graft rate (%) = (X-Y)/Y x 100
X: amount of acetone-insoluble matter after vacuum drying (g)
Y: Amount of rubbery polymer in graft copolymer (g)
Reduced viscosity of acetone solubles (dl/g)
After dissolving the acetone-soluble matter in N,N-dimethylformamide to obtain a solution with a concentration of 0.4 g/100 ml, the reduced viscosity is determined from the flowing time measured at 30° C. using a Canon Fenske viscosity tube.

The graft copolymer (B) obtained as described above is usually grafted with a monomer component including the monomer component (b-2) grafted onto the rubbery polymer (b-1). A copolymer mainly containing a polymer (B1 component) and copolymerized with a monomer component containing a monomer component (b-2) not grafted to the rubbery polymer (b-1) (referred to as the B2 component). Therefore, in the present invention, when the B2 component contained in the graft copolymer (B) satisfies the monomer components constituting the copolymer (C), it means that the copolymer (C) is contained. do.

The polymerization method of the graft copolymer (B) is not particularly limited. preferably legal.

When the graft copolymer (B) is produced by an emulsion polymerization method, the product is usually a latex. The obtained latex can be powdered through the steps of coagulation, washing, dehydration and drying. As the coagulant used in the coagulation step, one or more of sulfuric acid, magnesium sulfate, calcium chloride, aluminum sulfate, etc. dissolved in water can be used. Alternatively, a recovery and drying method using a spray dryer or the like can be used without using a coagulant.

The resin pH of the graft copolymer (B) should be 3 to 6.6, preferably 4 to 6.3. It is more preferably 4.5 to 5.9. By adjusting the amount within the above range, a product having excellent thermal stability can be obtained. The resin pH is measured using the graft copolymer (B) in a solid state such as powder or granules by the method described in Examples.

As a method for adjusting the resin pH of the graft copolymer (B), for example, when it is obtained by an emulsion polymerization method, the powder obtained by adjusting the pH of the slurry (aqueous dispersion of coagulated particles) obtained in the coagulation step of the resin pH can be adjusted. For example, it can be obtained by adding an acidic aqueous solution such as sulfuric acid or hydrochloric acid in the coagulation step to adjust the pH of the slurry to be low.

The copolymer (C) is obtained by polymerizing a monomer component containing an aromatic vinyl-based monomer and a vinyl cyanide-based monomer.

Examples of aromatic vinyl monomers constituting the copolymer (C) include styrene, α-methylstyrene, paramethylstyrene, bromostyrene and the like, and one or more of them can be used.

Examples of vinyl cyanide-based monomers constituting the copolymer (C) include acrylonitrile, methacrylonitrile, ethacrylonitrile, fumaronitrile, and the like, and one or more of them can be used.

Furthermore, the copolymer (C) may contain other monomers copolymerizable with the aromatic vinyl-based monomer and the vinyl cyanide-based monomer. monomers, maleimide-based monomers, amide-based monomers, unsaturated carboxylic acid-based monomers, polyfunctional monomers, etc., and one or more of them can be used. As these monomers, those similar to the monomer component (b-2) described above can be used.

The composition ratio of the monomers constituting the copolymer (C) is not particularly limited, but the aromatic vinyl monomer 50 to 90% by mass, the vinyl cyanide monomer 10 to 50% by mass, and the copolymer Composition ratio of 0 to 40% by mass of other possible monomers, 20 to 70% by mass of aromatic vinyl monomers, 10 to 60% by mass of vinyl cyanide monomers, (meth)acrylic acid ester monomers A composition ratio of 20 to 70% by mass of a monomer and 0 to 50% by mass of another copolymerizable monomer can be mentioned.

Although the reduced viscosity of the copolymer (C) is not particularly limited, it is preferably 0.2 to 1.5 dl/g, more preferably 0.3 to 1.5 dl/g from the viewpoint of the balance of physical properties such as impact resistance and fluidity. More preferably 0 dl/g.

The reduced viscosity can be obtained by the following formula.

After the copolymer (C) was dissolved in N,N-dimethylformamide to obtain a solution with a concentration of 0.4 g/100 ml, the reduced viscosity was measured at 30° C. using a Canon Fenske viscosity tube. Ask.

There are no particular restrictions on the polymerization method of the copolymer (C) constituting the thermoplastic resin composition. can do.

Talc (D) is hydrous magnesium silicate having a layered structure, and preferably has an average particle size of 0.1 to 50 μm, more preferably 0.5 to 25 μm, as measured by a laser diffraction particle size measurement method. , 1 to 15 μm.

The phosphoric acid compound (E) is a compound in which a hydroxyl group and an oxo group are bonded to a phosphorus atom, and examples thereof include phosphoric acid, phosphorous acid, hypophosphorous acid, polyphosphoric acid, methyl phosphate, and dimethyl phosphate.

The content of the polycarbonate resin (A) constituting the thermoplastic resin composition of the present invention is 40 to 80% by mass in the total 100% by mass of (A), (B), (C) and (D). It is preferably 42 to 77% by mass, more preferably 47 to 75% by mass. By adjusting the content within the above range, the balance between fluidity, impact resistance, and heat resistance can be improved.

The content of the graft copolymer (B) constituting the thermoplastic resin composition of the present invention is 5 to 45% by mass in the total 100% by mass of (A), (B), (C) and (D). and preferably 7 to 35% by mass, more preferably 10 to 28% by mass. Impact resistance can be improved by adjusting to the said range.

The content of the copolymer (C) constituting the thermoplastic resin composition of the present invention is 0 to 39% by mass in the total 100% by mass of (A), (B), (C) and (D). It is preferably from 2 to 36% by mass, more preferably from 4 to 33% by mass. Fluidity (moldability) can be improved by adjusting the content within the above range.

The content of talc (D) constituting the thermoplastic resin composition of the present invention is 5 to 24% by mass with respect to the total 100% by mass of (A), (B), (C) and (D). It is preferably 8 to 23% by mass, more preferably 12 to 22% by mass. The dimensional stability and weather resistance can be improved by adjusting the content within the above range.

The content of the phosphoric acid compound (E) constituting the thermoplastic resin composition of the present invention is 0.01 to 0.01 with respect to a total of 100 parts by mass of (A), (B), (C) and (D). It should be 1.5 parts by mass, preferably 0.03 to 1.0 parts by mass, more preferably 0.05 to 0.7 parts by mass. Thermal stability can be improved by adjusting the content within the above range.

The thermoplastic resin composition of the present invention may also contain other thermoplastic resins within a range that does not impair the effects of the present invention. Examples of such other thermoplastic resins include acrylic resins such as polymethyl methacrylate; polyolefin resins such as polyethylene and polypropylene; polyester resins such as polybutylene terephthalate resin, polyethylene terephthalate resin, and polylactic acid resin; polyamide resin; A polyimide resin or the like can be used.

Further, the thermoplastic resin composition of the present invention may contain a hindered amine-based light stabilizer; an antioxidant such as a hindered phenol, a sulfur-containing organic compound, and a phosphorus-containing organic compound, as long as the effects of the present invention are not impaired. Phenol-based, acrylate-based heat stabilizers; Benzoate-based, benzotriazole-based, benzophenone-based, salicylate-based UV absorbers; Organic nickel-based, higher fatty acid amides, etc. lubricants; Polybromophenyl ether, tetrabromo Halogen-containing compounds such as bisphenol-A, brominated epoxy oligomers, brominated compounds, phosphoric acid esters, flame retardants and auxiliary flame retardants such as antimony trioxide; odor masking agents; pigments such as carbon black and titanium oxide; dyes, etc. can also be added. Furthermore, reinforcing agents and fillers such as calcium carbonate, aluminum hydroxide, glass fibers, glass flakes, glass beads, glass wool, carbon fibers and metal fibers can also be added.

Among them, it is preferable to include 3 to 13 parts by mass of phosphate ester with respect to a total of 100 parts by mass of (A), (B), (C) and (D) in terms of improving fluidity, and 4 to 10 parts by mass. It is more preferable to include a part. Specific examples of phosphate esters include trimethyl phosphate, triethyl phosphate, tributyl phosphate, tri(2-ethylhexyl) phosphate, tributoxyethyl phosphate, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, tris(isopropylphenyl) Phosphate, tris(phenylphenyl)phosphate, trinaphthyl phosphate, cresyldiphenylphosphate, xylenyldiphenylphosphate, diphenyl(2-ethylhexyl)phosphate, di(isopropylphenyl)phenylphosphate, monoisodecylphosphate, 2-acryloyloxyethyl Acid phosphate, 2-methacryloyloxyethyl acid phosphate, diphenyl-2-acryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, melamine phosphate, dimelamine phosphate, melamine pyrophosphate, triphenylphosphine oxide, tricresylphosphine oxide , diphenyl methanephosphonate, diethyl phenylphosphonate, resorcinol polyphenyl phosphate, resorcinol poly(di-2,6-xylyl) phosphate, bisphenol A polycresyl phosphate, hydroquinone poly(2,6-xylyl) phosphate and condensation thereof and condensed phosphate esters such as Condensed phosphates include resorcinol bis(di-2,6-xylyl) phosphate, resorcinol bis(diphenyl phosphate), bisphenol A bis(diphenyl phosphate) and the like. Commercial products of resorcinol bis(di-2,6-xylyl) phosphate include PX-200 (manufactured by Daihachi Chemical Industry Co., Ltd.). Commercially available products of resorcinol bis(diphenyl phosphate) include CR-733S (manufactured by Daihachi Chemical Industry Co., Ltd.). Commercially available products of bisphenol A bis(diphenyl phosphate) include CR-741 (manufactured by Daihachi Chemical Industry Co., Ltd.). Among them, resorcinol bis(di-2,6-xylyl) phosphate and bisphenol A bis(diphenyl phosphate) are preferably used because of their excellent hydrolysis resistance, heat resistance and low volatility.

The thermoplastic resin composition of the present invention can be obtained by melt-kneading the above components. For melt-kneading, known kneaders such as rolls, Banbury mixers, single-screw extruders, multi-screw extruders and kneaders can be used.

The thermoplastic resin composition thus obtained can be molded by injection molding, extrusion molding, compression molding, injection compression molding, blow molding, or the like to obtain a molded product.

EXAMPLES The present invention will be specifically described below using Examples, but the present invention is not limited to these. The parts and percentages shown in the examples are based on weight.
Various physical properties in each example and comparative example are measured by the following methods.

Charpy impact strength (NC)
Using the pellets obtained in each example and comparative example, various test pieces were molded according to ISO test method 294, and the notched Charpy impact value was measured according to ISO test method 179 with a thickness of 4 mm. Unit: kJ/ ^m2

Deflection temperature under load (HDT)
Using the pellets obtained in each example and comparative example, various test pieces were molded according to ISO test method 294, and the deflection temperature under a load of 1.8 MPa was measured according to ISO75. Unit: °C

Using a thermal stability injection molding machine (Japan Steel Works, Ltd. J-180ADS, molding temperature 290 ° C., mold temperature 60 ° C.), a flat plate test piece (length × width × thickness = 400 mm × 100 mm × 3 mm) were molded. About 140% of the material weighed for the molded product was weighed and molded. Next, about 140% of the resin was weighed in such a manner that about 40% of the resin remaining in the cylinder was contained, and then held for 270 seconds and molded at a shooting speed of 30 mm/s. It was visually determined whether or not the appearance of the obtained molded product was defective. The poor appearance was evaluated as follows.
○: No silver dots on the surface of the molded product △: There are 1 to less than 10 silver dots on the surface of the molded product ×: There are 10 or more silver dots on the surface of the molded product

Dimensional stability A coefficient of linear expansion was measured as an evaluation of dimensional stability.
Based on ISO test method 294, dumbbells of type A1 in JIS K7139 were molded. A sample was cut out from the central portion of the dumbbell, and the coefficient of linear expansion in the MD direction (flow direction of the resin) was measured according to JIS K7197. As a thermal analyzer, TMA-7100 manufactured by Hitachi High-Tech Science Co., Ltd. was used.
The lower the numerical value, the better the dimensional stability, which was evaluated as follows.
○: Linear expansion coefficient is less than 5 × 10 ^-5 /°C △: Linear expansion coefficient is 5 × 10 ^-5 /°C or more and 7 × 10 ^-5 /°C or less ×: Linear expansion coefficient is 7 × 10 ^-5 /°C surpass

Weather resistance In the weather resistance test, the pellets obtained in each example and comparative example were used, and molded products (longitudinal x Width x Thickness = 90 mm x 55 mm x 2.5 mm) was used. Using a Sunshine Weather Meter S80HBB manufactured by Suga Test Instruments Co., Ltd., an accelerated exposure test was performed for 500 hours under the conditions of a BPT of 63° C. and rain. After that, the color difference (ΔE) was measured by the SCE method before and after the exposure of the surface of the molded product. The color difference was evaluated as follows using a spectrophotometer (CMS-35SP JC2 type manufactured by Murakami Color Research Laboratory Co., Ltd.).
○: ΔE is less than 7 △: ΔE is 7 or more and 15 or less ×: ΔE is more than 15

Resin pH
(1) 1 g of the graft copolymer (B) and 40 ml of primary tetrahydrofuran (containing a stabilizer) were added to a 100 ml Erlenmeyer flask and allowed to stand for 24 hours.
(2) Add 40 ml of primary methanol to a 200 ml beaker and stir with a magnetic stirrer. The sample obtained in (1) is added thereto, and then 40 ml of pure water is added and stirred.
(3) The pH of the sample obtained in (2) was measured according to JIS Z-8802. A desktop electrical conductivity meter (CM-25R manufactured by Toa DKK Co., Ltd.) was used to measure the pH.

Polycarbonate resin (A)
A polycarbonate resin composed of phosgene and bisphenol A and having a viscosity average molecular weight of 20,500.

Production of graft copolymer (B-1) In a glass reactor, coagulated enlarged styrene-butadiene rubber (b-1) latex (5% by mass of styrene, 95% by mass of butadiene, mass average particle size of 440 nm) was added in terms of solid content. 60 parts by mass were charged, stirring was started, and nitrogen substitution was performed. After purging with nitrogen, the inside of the tank was heated to 65° C., and 0.06 parts by mass of glucose, 0.03 parts by mass of anhydrous sodium pyrophosphate and 0.001 parts by mass of ferrous sulfate were added to 10 parts by mass of deionized water. After adding an aqueous solution dissolved in , the temperature was raised to 70°C. After that, a mixture of 10 parts by weight of acrylonitrile, 30 parts by weight of styrene, 0.3 parts by weight of tertiary dedodecyl mercaptan, and 0.1 parts by weight of t-butyl hydroperoxide and 1.0 parts by weight of potassium oleate (in terms of solid content) were added. An emulsifier aqueous solution dissolved in 20 parts by mass of deionized water was continuously added dropwise over 4 hours. After dropping, the mixture was held for 3 hours to obtain a graft copolymer (B-1) latex. Thereafter, deionized water was added to 100 parts by mass (solid content) of the graft copolymer (B-1) latex obtained so that the final slurry concentration was 23%, and 4.5 parts by mass of magnesium sulfate and , and 0.8 parts by mass of 10% sulfuric acid were added and heated to 93°C. Thereafter, the graft copolymer (B-1) latex was added and coagulated to obtain a slurry containing the polymer. Thereafter, the obtained slurry was dehydrated and dried to obtain a powder of graft copolymer (B-1). The resulting graft copolymer (B-1) had a graft ratio of 42%, a reduced viscosity of the acetone-soluble portion of 0.28 dl/g, and a resin pH of 5.4.
The mass average particle size of the coagulated enlarged styrene-butadiene rubber latex was determined as follows.
It was stained with osmium tetroxide (OsO4) and photographed with a transmission electron microscope after drying. Using an image analysis processor (device name: IP-1000PC manufactured by Asahi Kasei Corp.), the area of 800 rubber particles was measured, the circle equivalent diameter (diameter) was obtained, and the mass average particle diameter was calculated.

Production of graft copolymer (B-2) 100 parts by mass (solid content) of the obtained graft copolymer (B-1) latex was deionized so that the final slurry concentration was 23%. Water was charged, 4.5 parts by mass of magnesium sulfate was added, and the mixture was heated to 93°C. Thereafter, the graft copolymer (B-1) latex was added and coagulated to obtain a slurry containing the polymer. Thereafter, the obtained slurry was dehydrated and dried to obtain a powder of graft copolymer (B-2). The resulting graft copolymer (B-2) had a graft ratio of 42%, a reduced viscosity of the acetone-soluble portion of 0.28 dl/g, and a resin pH of 8.4.

Production of Copolymer (C) A copolymer (C) consisting of 75 parts by mass of styrene and 25 parts by mass of acrylonitrile was obtained by a known bulk polymerization method. The reduced viscosity of the copolymer (C) obtained by the method described above was 0.50 dl/g.

Talc (D)
Talc: UPN-HST 0.5 manufactured by Hayashi Kasei Co., Ltd.

Phosphate compound (E)
FUJIFILM Wako Pure Chemical Co., Ltd. Diphosphoric acid

Other additives Made by Daihachi Chemical Industry Co., Ltd., aromatic condensed phosphate: PX-200

Examples 1-6 and Comparative Examples 1-5
After mixing the polycarbonate resin (A), the graft copolymer (B), the copolymer (C), the talc (D), the phosphoric acid compound (E) and other additives in the proportions shown in Table 1, the cylinder temperature The mixture was melt-kneaded and pelletized in a twin-screw extruder with a diameter of 26 mm set at 260° C. under the conditions of a main screw rotation speed of 450 rpm and a discharge rate of 30 kg/hr. Using the pellets, various test pieces for evaluation were molded by an injection molding machine.

As is clear from Table 1, Examples 1 to 6 using the thermoplastic resin composition of the present invention were excellent in the balance of impact resistance, heat resistance, weather resistance, dimensional stability and thermal stability. was taken.
In Comparative Example 1, the resin pH of the graft copolymer (B) was outside the specified range of the present invention, and the thermal stability was poor.
Comparative Example 2 was inferior in thermal stability because the phosphoric acid compound (E) was not added.
Comparative Example 3 was inferior in thermal stability because the amount of the phosphoric acid compound (E) added exceeded the specified range of the present invention.
Comparative Example 4 was inferior in dimensional stability and weather resistance because talc (D) was not added.
Comparative Example 5 was inferior in impact resistance because the amount of talc (D) added exceeded the specified range of the present invention.

As described above, the thermoplastic resin composition of the present invention is a thermoplastic resin composition having an excellent balance of impact resistance, heat resistance, weather resistance, dimensional stability and thermal stability. etc., it can be suitably used as a material for large-sized molded parts used outdoors.

Claims (2)

Thermoplastic resin containing polycarbonate resin (A), graft copolymer (B), copolymer (C), talc (D) and phosphoric acid compound (E) and satisfying the following conditions (1) to (8) Composition.
(1) The content of the polycarbonate resin (A) is 40 to 80% by mass in the total 100% by mass of (A), (B), (C) and (D).
(2) The graft copolymer (B) is selected from the rubbery polymer (b-1), an aromatic vinyl-based monomer, a vinyl cyanide-based monomer, and a (meth)acrylic acid ester-based monomer. A graft copolymer obtained by graft polymerization with a monomer component (b-2) containing at least one of
(3) The resin pH of the graft copolymer (B) is 3 to 6.6.
(4) The content of the graft copolymer (B) is 5 to 45% by mass in the total 100% by mass of (A), (B), (C) and (D).
(5) Copolymer (C) is a copolymer obtained by polymerizing a monomer component containing an aromatic vinyl-based monomer and a vinyl cyanide-based monomer.
(6) The content of the copolymer (C) is 0 to 39% by mass in the total 100% by mass of (A), (B), (C) and (D).
(7) The content of talc (D) is 5 to 24% by mass in the total 100% by mass of (A), (B), (C) and (D).
(8) The content of the phosphoric acid compound (E) is 0.01 to 1.5 parts by mass per 100 parts by mass of (A), (B), (C) and (D). 2. The thermoplastic resin composition according to claim 1, comprising 3 to 13 parts by mass of the phosphate ester with respect to a total of 100 parts by mass of (A), (B), (C) and (D).