JP2006169461A - Thermoplastic resin composition containing polycarbonate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoplastic resin composition containing a polycarbonate, excellent in impact resistance and molding processability on producing it and also humid heat resistant characteristic and heat resistant stability for maintaining its appearance. <P>SOLUTION: This thermoplastic resin composition is obtained by melting and mixing a graft copolymer obtained by a prescribed recovering method, a copolymer, a polycarbonate equipped with a limit in its molecular weight and a specific phosphorus-based stabilizer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thermoplastic resin composition containing a polycarbonate, and relates to a thermoplastic resin containing a polycarbonate characterized by excellent resistance to moisture and heat aging and heat stability to maintain the impact resistance, molding processability and appearance during production. The present invention relates to a resin composition.

  Polycarbonate is used in household electrical appliances, automotive interior materials, and exterior materials because of its excellent rigidity, heat resistance, and impact resistance. Polycarbonate has a high melt viscosity, is difficult to mold, has poor releasability from the mold, and has a large specific gravity. In recent years, mixing with rubber-reinforced styrene resin has resulted in low specific gravity and moldability. The use of improved materials is expanding. However, the alloy of polycarbonate and rubber reinforced resin is easily affected by the environment in which it is used, and it is a drawback that the physical properties may change particularly in a high temperature / high humidity environment, and efforts are being made to solve this problem.

For example, in Patent Document 1, in a polymer alloy of a polycarbonate resin and an ABS resin containing a flame retardant, by specifying the alkali metal content of the ABS resin and the acid value of the flame retardant used, a high temperature / high humidity environment The decrease in the tensile strength and tensile elongation at is suppressed.
JP-A-11-130954

  However, Patent Document 1 is a description of changes in mechanical properties of a molded product in a high temperature / high humidity environment. There is no description of the change in fluidity, and there is no solution to the problem that the moldability of the material changes after storage in this environment. Moreover, it cannot be said that the heat resistance stability of a molding machine or the like is sufficient. Furthermore, since additives such as phosphate ester compounds and epoxy stabilizers are used, there are concerns about handling during production and mold contamination during molding with additives.

  Therefore, the present invention can maintain the shock resistance, molding processability, and appearance at the time of manufacture even when the pre-molding material and the molded product are stored in a humid heat environment, and provide stability at high temperatures. A thermoplastic resin that achieves its purpose only by using specified graft copolymers, copolymers, polycarbonates, and phosphorus stabilizers without using additives, focusing on handling during production and mold contamination. An object is to provide a composition.

  As a result of intensive studies to solve the above problems, the present inventors have melt-mixed a graft copolymer obtained by a specified recovery method, a copolymer, a polycarbonate with a limited molecular weight, and a specific phosphorus stabilizer. It was found that the thermoplastic resin composition obtained by the treatment was effective.

That is, in the presence of the rubbery polymer (a), the aromatic vinyl monomer (a1), the vinyl cyanide monomer (a2), and another monomer (a3) copolymerizable therewith are used. The water content obtained by emulsion polymerization of the vinyl-based monomer mixture contained using a higher fatty acid ester salt-based emulsifier, and removing the emulsifier component to 0.3% or less of the polymer after acid coagulation. 5 to 40 parts by weight of graft copolymer (A) 5 to 40 parts by weight aromatic vinyl monomer (b1), vinyl cyanide monomer (b2) and other monomers copolymerizable therewith ( Water content of 1.5% or less prepared by copolymerizing a vinyl monomer mixture containing b3) and adjusting the oligomer (dimer, trimer) component to 1.0% or less based on the polymer Copolymer (B) 0 to 40 parts by weight Polycarbonate having a viscosity average molecular weight of 17,000 or more Phosphorus stabilizer comprising 10 to 90 parts by weight of the resin (C) and having a molecular weight of 200 to 1000 and a boiling point of 200 ° C. or more with respect to (A) + (B) + (C) = 100 parts by weight ( D) A thermoplastic resin composition containing a polycarbonate produced to be 0.1 to 5 parts by weight

  The thermoplastic resin composition of the present invention is excellent in moisture and heat aging characteristics that maintain impact resistance, molding processability, and appearance at the time of manufacture even when the material and molded product before molding are stored in a humid heat environment. The present invention provides a resin composition having good heat stability and low mold contamination. It is useful for various automobile exterior / interior parts, OA equipment, home appliances, general goods, housing equipment parts, and the like.

  The present invention will be specifically described below.

In the present invention, the graft copolymer (A) means an aromatic vinyl monomer (a1), a vinyl cyanide monomer (a2), and a copolymer thereof in the presence of the rubbery polymer (a). It is obtained by graft copolymerization of a vinyl monomer mixture containing another possible monomer (a3).
The graft copolymer here includes, in addition to the graft copolymerized rubber polymer, an ungrafted copolymer that dissolves in acetone, and these are referred to as a graft copolymer (A). .

  As the rubbery polymer (a), those having a glass transition temperature of 0 ° C. or lower are suitable, and diene rubber is preferably used. Specifically, polybutadiene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, styrene-butadiene block copolymer, diene rubber such as butyl acrylate-butadiene copolymer, and acrylic such as polybutyl acrylate. Rubber, polyisoprene, ethylene-propylene-diene terpolymer, and the like. Of these, polybutadiene or butadiene copolymer is preferred.

  The rubber particle diameter of the rubber polymer (a) is not particularly limited, but the weight average molecular weight of the rubber particles is preferably 0.10 to 0.50 μm from the viewpoint of impact resistance, and more preferably 0.18. ~ 0.40 μm. The weight average molecular diameter is the sodium alginate method described in “Rubber Age Age Vol. 88 p. 484 to 490 (1960) by E. Schmidt, PH Biddison” (concentration ratio of sodium alginate and cumulative sodium alginate concentration). The particle diameter of 50% cumulative weight fraction is obtained from the weight fraction).

  The copolymer (B) in the present invention contains an aromatic vinyl monomer (b1), a vinyl cyanide monomer (b2), and another monomer (b3) copolymerizable therewith. This is a copolymer obtained by copolymerizing a vinyl monomer mixture.

  Specific examples of the aromatic vinyl monomer used for the graft copolymer (A) and the copolymer (B) include styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, t-butylstyrene, o -Ethylstyrene, o-chlorostyrene, o, p-dichlorostyrene and the like are mentioned, and styrene and α-methylstyrene are particularly preferable. These can use 1 type (s) or 2 or more types.

  Specific examples of the vinyl cyanide monomer used for the graft copolymer (A) and the copolymer (B) include acrylonitrile, methacrylonitrile and ethacrylonitrile, with acrylonitrile being particularly preferred. These can use 1 type (s) or 2 or more types.

  There are no particular limitations on the other copolymerizable monomers used in the graft copolymer (A) and copolymer (B), but methyl (meth) acrylate, ethyl (meth) acrylate, (meth) N-propyl acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, chloromethyl (meth) acrylate and (meth ) Unsaturated carboxylic acid ester monomers such as 2-chloroethyl acrylate, polymerizable unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, vinyl acetic acid, itaconic acid, maleic acid, N-methylmaleimide, N -Maleimide monomers such as cyclohexylmaleimide and N-phenylmaleimide, unsaturated dicarboxylic acids such as maleic acid, maleic anhydride, etc. And unsaturated amides, such as unsaturated dicarboxylic acid anhydrides and acrylamide. Among them, unsaturated carboxylic acid ester monomer methyl methacrylate and unsaturated dicarboxylic acid anhydride maleic anhydride for the purpose of improving impact and compatibility, and maleimide monomer N- for improving heat resistance. Preferably phenylmaleimide is used.

  In the present invention, the method for producing the graft copolymer (A) is produced by an emulsion polymerization method from the viewpoint of suppressing deterioration of the rubber component due to excessive heat history and coloring. There is no particular limitation on the monomer charging method, and initial batch charging may be performed, a part or all of the monomer may be continuously charged in order to control the distribution of the copolymer composition, or one monomer may be charged. Parts or all may be divided and charged. Usually, emulsion polymerization involves emulsion graft polymerization of a monomer mixture in the presence of a rubbery polymer latex. A higher fatty acid ester salt system is used as an emulsifier for graft polymerization for the purpose of efficiently recovering the graft copolymer and improving the heat and heat aging resistance. Examples thereof include laurate, misty phosphate, palmitate, stearate, oleate, linoleate, linolenate, rosinate, behenate and the like. The salt here is an alkali metal salt, an ammonium salt or the like, and specific examples of the alkali metal salt include potassium salt, sodium salt and lithium salt. These emulsifiers may be used alone or in combination of two or more.

  In the present invention, the method for recovering the graft copolymer (A) needs to be performed by acid coagulation. Specific examples of the coagulant include sulfuric acid, hydrochloric acid, phosphoric acid, acetic acid, formic acid, nitric acid and the like. These may be used alone or in combination of two or more, but sulfuric acid and acetic acid are particularly preferred. More preferably, one type of sulfuric acid is used. When the salt coagulation is carried out, the fatty acid metal salt remains in the graft copolymer, so that the physical properties are greatly deteriorated in a high-temperature and high-humidity environment, and the thermal stability is deteriorated.

  In addition, when the fatty acid (emulsifier component) produced when solidified with an acid is present in the graft copolymer (A), it plays a role in improving the impact. On the other hand, in a high temperature / high humidity environment, the impact strength of the molded product is reduced. In order to greatly change the moldability of the material, it is necessary to remove it until it becomes 0.3% or less of the polymer component. If the fatty acid remains in excess of 0.3%, the change in physical properties in a high temperature / high humidity environment becomes significant and does not reach the object of the present invention.

  The recovery method by acid coagulation of the emulsion polymerized product is not particularly limited. A method of obtaining graft copolymer particles by introducing an emulsion polymerization product into an acidic slurry, a method of collecting an acidic aqueous solution into an emulsion polymerization latex and recovering it, and dividing the coagulation process into two or more stages by adding a temperature gradient from low temperature to high temperature. A method of agglomeration / recovery, a method of agglomeration / recovery in two or more stages by adding an acidity gradient from weak acid to strong acid or from strong acid to weak acid in the coagulation process. It can also be selected and collected. Preferably, the emulsion polymerization product is charged into an acidic slurry and the graft copolymer is recovered. More preferably, the coagulation step is recovered by combining this method with a method of setting the temperature gradient from low to high. Is the method.

  A method for removing the emulsifier component remaining after the coagulation step is not particularly specified, but a method of dissolving in an aqueous solution using an alkaline aqueous solution or the like is preferable. Examples of the alkaline aqueous solution include a potassium hydroxide aqueous solution, a sodium hydroxide aqueous solution, and a magnesium hydroxide aqueous solution. A potassium hydroxide aqueous solution and a sodium hydroxide aqueous solution are preferred. Thereafter, a method of recovering the graft copolymer by adjusting the emulsifier component to 0.3% or less through washing, dehydration and drying steps, etc.

  In the present invention, the method (dehydration / drying) of suppressing the water content of the graft copolymer (A) is not particularly limited. The moisture content of the obtained graft copolymer needs to be 1.5% or less. Preferably it is 1.0% or less. If it exceeds 1.5%, the appearance of the resulting thermoplastic resin composition is poor and the impact strength is not sufficient.

  In the present invention, the production method of the copolymer (B) is not limited, and examples thereof include bulk polymerization, solution polymerization, bulk suspension polymerization, suspension polymerization, and emulsion polymerization. In the thermoplastic composition containing polycarbonate, the smaller the polymerization residue (polymerization initiator, polymerization aid, oligomer) other than the composition, the smaller the oligomer, especially the more beautiful the appearance during molding, and the higher the temperature and humidity. Suspension polymerization or emulsion polymerization that can remove the polymerization residue using water and can remove the polymerization residue in the drying step is preferable because the change in physical properties in the environment can be suppressed. More preferred is suspension polymerization.

  It is necessary to adjust the oligomer component contained in the copolymer to 1.0% or less. Preferably it is 0.6% or less. If it is 1.0% or more, the physical properties deteriorate significantly in a high temperature / high humidity environment, and the molded appearance also deteriorates. The removal method is not particularly limited.

  In the present invention, the method (dehydration / drying) for suppressing the water content of the copolymer (B) is not particularly limited. The moisture content of the obtained graft copolymer needs to be 1.5% or less. Preferably it is 1.0% or less. If it exceeds 1.5%, the appearance of the resulting thermoplastic resin composition is poor and the impact strength is not sufficient.

  In the present invention, as the initiator used for the polymerization of the graft copolymer (A) and the copolymer (B), a peroxide or an azo compound is used. Specific examples of the peroxide include benzoyl peroxide, cumene hydroperoxide, dicumyl peroxide, diisopropylbenzene hydroperoxide, t-butyl hydroperoxide, t-butyl cumyl peroxide, t-butyl peroxyacetate, t-butyl peroxybenzoate, t-butyl peroxyisopropyl carbonate, di-t-butyl peroxide, t-butyl peroctate, 1,1-bis (t-butylperoxy) 3,3,5-trimethyl Examples include cyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, and t-butylperoxy-2-ethylhexanoate. Of these, cumene hydroperoxide and 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane are particularly preferably used. Specific examples of azo compounds include azobisisobutyronitrile, azobis (2,4dimethylvaleronitrile), 2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile, 2-cyano-2-propylazoformamide. 1,1'-azobiscyclohexane-1-carbonitrile, azobis (4-methoxy-2,4-dimethylvaleronitrile), dimethyl 2,2'-azobisisobutyrate, 1-t-butylazo-1- And cyanocyclohexane, 2-t-butylazo-2-cyanobutane, 2-t-butylazo-2-cyano-4-methoxy-4-methylpentane, and the like. When using these initiators, they are used alone or in combination of two or more. Of these, azobisisobutyronitrile is particularly preferably used.

  In carrying out the polymerization, chain transfer agents such as mercaptans and terpenes can be used for the purpose of adjusting the degree of polymerization of the obtained graft copolymer (A) and copolymer (B). N-octyl mercaptan, t-dodecyl mercaptan, n-dodecyl mercaptan, n-tetradecyl mercaptan, n-octadecyl mercaptan, terpinolene and the like. When using these chain transfer agents, they are used alone or in combination of two or more. Of these, n-octyl mercaptan, t-dodecyl mercaptan, and n-dodecyl mercaptan are preferably used.

  Next, polycarbonate will be described. The polycarbonate (C) used in the present invention is generally 2,2-bis (4-oxyphenyl) alkane, bis (4-oxyphenyl) ether, bis (4-oxyphenyl) sulfone, sulfide or sulfoxide. A polymer or copolymer made of bisphenols such as those of the type is used. An aromatic polycarbonate produced by any method can be used. Specifically, for the production of polycarbonate from 4,4′-dihydroxydiphenyl-2,2-propane (commonly known as bisphenol A), a phosgene method in which phosgene is blown in the presence of a caustic aqueous solution and a solvent, or 4 , 4′-dihydroxydiphenyl-2,2′-propane and a carbonic acid diester can be used by transesterification in the presence of a catalyst.

  The polycarbonate (C) used in the present invention has a viscosity average molecular weight of 17000 or more, preferably 18000 to 30000. If it is less than 17000, the impact strength is not sufficient, and the change in physical properties in a high-temperature and high-humidity environment is significant as compared with polycarbonate having a high average molecular weight. If the molecular weight is too high, the moldability is adversely affected, and therefore it is necessary to adjust within an appropriate range. Two or more kinds of polycarbonates (C) having different molecular weights can be used in combination. Further, two or more kinds of polycarbonates (C) having different production methods can be used in combination.

  In the thermoplastic resin composition of the present invention, the graft copolymer (A) is 5 to 40 parts by weight, preferably 5 to 35 parts by weight. When the graft copolymer (A) exceeds 40 parts by weight, there is a problem that the appearance at the time of molding deteriorates, and when it is less than 5 parts by weight, the impact resistance of the obtained thermoplastic resin composition is not sufficient.

  In the thermoplastic resin composition of the present invention, the copolymer (B) is 0 to 40 parts by weight, preferably 0 to 35 parts by weight. When the copolymer (B) exceeds 40 parts by weight, the impact resistance of the resulting thermoplastic resin composition is not sufficient.

  In the thermoplastic resin composition of the present invention, the polycarbonate (C) is 10 to 90 parts by weight, preferably 20 to 80 parts by weight. When the polycarbonate (C) exceeds 90 parts by weight, the molding processability of the resulting thermoplastic resin composition is poor, which is not preferable. On the other hand, if the amount is less than 10 parts by weight, the resulting thermoplastic resin composition has insufficient impact resistance and heat resistance.

  The phosphorus stabilizer (D) used in the present invention is trimethyl phosphite, diethyl phosphite, triethyl phosphite, tricyclohexyl phosphite, triphenyl phosphite, triallyl phosphite, tricresyl phosphite, trixylate. Nyl phosphite, phenyl diisodecyl phosphite, diphenyl isodecyl phosphite, tris (monononylphenyl) phosphite, tris (monononylphenyl) phosphite, tris (dinonylphenyl) phosphite, hydroxyphenyl diphenyl phosphite, etc. Examples include phosphate esters and compounds obtained by modifying these with various substituents. Phenyl diisodecyl phosphite and diphenyl isodecyl phosphite are preferred.

  This phosphorus stabilizer is excellent in the antioxidant effect of the resin and the neutralizing effect of the remaining alkali metal component in the resin, and can suppress hydrolysis of the polycarbonate. These can be used alone or in combination of two or more.

  The phosphorus stabilizer (D) used in the present invention is required to have a molecular weight of 200 to 1000 and a boiling point of 200 ° C. or higher. When the molecular weight is less than 200, the appearance of the molded product is poor. When the molecular weight is more than 1000, the heat resistance stability of the resulting resin composition is significantly lowered. On the other hand, if the boiling point is lower than 200 ° C., it will be degassed during extrusion kneading, and the physical stability and heat resistance stability of the resulting resin composition at high temperature and high humidity will decrease.

  The addition amount of the phosphorus stabilizer (D) used in the present invention is 0.1 to 5 parts by weight with respect to 100 parts by weight of component (A) + (B) + (C). Preferably, it is in the range of 0.05 to 3 parts by weight, and the thermoplastic resin obtained in this range is excellent in moisture heat aging resistance, heat resistance stability and impact resistance balance. If the phosphorus compound (C) is less than 0.01 parts by weight, the resulting thermoplastic resin composition has insufficient physical properties and heat stability under high temperature and high humidity conditions. The resulting thermoplastic resin composition has insufficient impact resistance.

  The thermoplastic resin composition of the present invention can contain an additive having an alkali neutralizing effect such as maleic anhydride, if necessary.

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

  However, it is not preferable to add a fatty acid material such as a higher fatty acid amide, a higher fatty acid ester, or a higher fatty acid metal salt as a lubricant.

Furthermore, fiber-based reinforcing agents such as glass fibers, glass flakes, glass beads, carbon fibers, and metal fibers can be added to the thermoplastic resin composition of the present invention as necessary.
Further, spherical and irregular fillers such as asbestos, potassium titanate, calcium carbonate, wollastonite, talc, mica, clay, barium sulfate, titanium oxide, and aluminum oxide can be added as necessary.

  It does not restrict | limit in particular regarding the manufacturing method of the thermoplastic resin composition of this invention. A method of melt mixing using a single screw or a twin screw in a cylinder having a heating device can be employed, and it is particularly preferable to use a twin screw. The temperature gradient at the time of melt mixing can be freely set within the range where the heating temperature does not impair the object of the present invention. A method in which a graft copolymer (A) and a copolymer (B) are melt-mixed to produce a rubber-reinforced styrene resin and then melt-mixed with the polycarbonate (C), or the graft copolymer (A) and the copolymer In the middle of melting and kneading (B), the method of manufacturing by melt-kneading by side-feeding the polycarbonate (C), the graft copolymer (A), the copolymer (B), and the polycarbonate (C) were all blended. Examples thereof include a production method in which melt-kneading is performed later. The method for adding the phosphorus stabilizer (D) is not particularly limited, but is preferably mixed before melting.

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

  The thermoplastic resin composition of the present invention has a heat-and-heat aging characteristic and a heat-resistant stability that maintain impact resistance, molding processability, and appearance even when the material and the molded product before molding are stored in a humid-heat environment. Taking advantage of its excellent features, it is suitable for housings such as OA equipment and home appliances, parts thereof, and automobile parts. In addition, use after long-term storage in the summer or in the tropical region is also convenient because it does not have a significant effect during molding.

  In order to describe the present invention more specifically, examples and comparative examples are given below, but these examples do not limit the present invention. Unless otherwise specified, “%” indicates wt% and “parts” indicates parts by weight. A method for analyzing the resin characteristics of the thermoplastic resin composition will be described below.

(1) Weight average rubber particle diameter “Rubber Age Vol. 88 p. Utilizing the fact that the diameter is different, the particle diameter of 50% cumulative weight fraction is obtained from the weight ratio of creamed weight and the cumulative weight fraction of sodium alginate concentration).

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

Graft rate (%) = {[(n) − (m) × L] / [(m) × L]} × 100
(3) Izod impact strength: ASTM D256-56A (measured at 23 ° C., test piece thickness = 6.4 mm)
(4) MFR (Melt flow rate measurement): ISO 1133 (240 ° C., 98 N load)
(5) Tensile strength / elongation: ASTM
(6) Appearance of molded product The molded product appearance evaluation test was evaluated as follows. Using an injection molding machine, set the cylinder temperature to 280 ° C and the mold temperature to 60 ° C. Resin stays in the cylinder for 15 minutes, and then molds a 50 × 40 × 3mmt square plate. The presence or absence of silver streak (silver-like pattern) was visually determined.

  A: No flow mark or silver streak was observed.

  A: A small silver streak with a diameter of less than 2 mm was observed near the gate.

  Δ: Silver streak having a diameter of less than 10 mm was observed in the vicinity of the gate.

  X: Silver streaks were observed throughout the molded product.

  Similarly, after holding at a cylinder temperature of 280 ° C. for 15 minutes, Izod impact (test piece thickness = 6.4 mm) test pieces were molded up to 6 shots, and the numerical value of the shot with the lowest impact before and after staying Thermal stability was determined by the retention calculated from

(7) Humidity and heat aging characteristics A test piece or material is placed in a high-temperature / high-humidity environment tank at 85 ° C./95% RH, and the change in physical properties of the material is evaluated at the rate of change for each elapsed time. Evaluation is performed with three items of “Izod impact”, “tensile elongation”, and “MFR”.

Reference Example 1 Production of Graft Copolymer (A) (1) Preparation of Graft Copolymer (A-1) 55 parts of polybutadiene latex (weight average rubber particle size 0.21 μm, gel content 80%) (in terms of solid content) ) In the presence of 70) styrene and 30% acrylonitrile (45 parts) was emulsion-polymerized using potassium stearate to obtain a rubber-reinforced styrene resin latex.
After adding to a 0.3% dilute sulfuric acid aqueous solution at 90 ° C. and agglomerating, neutralizing with an aqueous sodium hydroxide solution, washing, dehydration, and drying steps are performed, and the emulsifier component rate is 0.22% and the moisture content is 0.6%. A graft copolymer (A-1) was prepared. The graft rate was 42%.

(2) Preparation of graft copolymer (A-2) Styrene 23%, acrylonitrile 8% in the presence of 55 parts (in terms of solid content) of polybutadiene latex (weight average rubber particle size 0.21 μm, gel content 80%) Then, 45 parts of a monomer consisting of 69% methyl methacrylate was emulsion-polymerized using potassium stearate to obtain a rubber-reinforced styrene resin latex. After adding to a 0.3% dilute sulfuric acid aqueous solution at 90 ° C. and agglomerating, neutralizing with an aqueous sodium hydroxide solution, washing, dehydration, and drying steps are performed, and the emulsifier component ratio is 0.18% and the water content is 0.8%. A graft copolymer (A-2) was prepared. The graft rate was 45%.

(3) Preparation of graft copolymer (A-3) Styrene 23%, acrylonitrile 8% in the presence of 55 parts (in terms of solid content) of polybutadiene latex (weight average rubber particle diameter 0.21 μm, gel content 80%) Then, 45 parts of a monomer consisting of 69% methyl methacrylate was emulsion-polymerized using potassium stearate to obtain a rubber-reinforced styrene resin latex. Washing / dehydration / drying steps after the mild aggregation slurry added to the 0.3% dilute sulfuric acid aqueous solution at 75 ° C. is heated in a 95 ° C. heating tank to complete the aggregation, and neutralized with an aqueous sodium hydroxide solution Then, a graft copolymer (A-3) having an emulsifier component ratio of 0.17% and a water content of 0.5% was prepared. The graft rate was 42%.

(4) Preparation of graft copolymer (A-4) 70% styrene and 30% acrylonitrile in the presence of 55 parts (in terms of solid content) of polybutadiene latex (weight average rubber particle size 0.21 μm, gel content 80%) 45 parts of the monomer was emulsion-polymerized using potassium stearate to obtain a rubber-reinforced styrene resin latex.
Add to a 0.3% dilute hydrochloric acid aqueous solution at 90 ° C and agglomerate, neutralize with an aqueous sodium hydroxide solution, and then go through washing, dehydration, and drying steps to obtain a graft with 0.22% emulsifier component and 0.6% moisture content A copolymer (A-4) was prepared. The graft rate was 42%.

(5) Preparation of graft copolymer (A-5) 70% styrene and 30% acrylonitrile in the presence of 55 parts (in terms of solid content) of polybutadiene latex (weight average rubber particle diameter 0.21 μm, gel content 80%) 45 parts of the monomer was emulsion-polymerized using potassium stearate to obtain a rubber-reinforced styrene resin latex.
Add to 0.3% dilute sulfuric acid aqueous solution and agglomerate, and after neutralization with sodium hydroxide aqueous solution, go through washing, dehydration, and drying steps, and the emulsifier component rate is 0.56% and the moisture content is 0.6%. A graft copolymer (A-5) was prepared. The graft rate was 42%.

(6) Preparation of graft copolymer (A-6) 70% styrene and 30% acrylonitrile in the presence of 55 parts (in terms of solid content) of polybutadiene latex (weight average rubber particle size 0.21 μm, gel content 80%) 45 parts of the monomer was emulsion-polymerized using potassium stearate to obtain a rubber-reinforced styrene resin latex.
After adding to a 0.6% magnesium sulfate aqueous solution and agglomerating, a graft copolymer (A-6) having a moisture content of 0.9% was prepared through washing, dehydration and drying steps. The graft rate was 42%.

(7) Preparation of graft copolymer (A-7) 70% styrene, 30% acrylonitrile in the presence of 55 parts (in terms of solid content) of polybutadiene latex (weight average rubber particle size 0.21 μm, gel content 80%) 45 parts of the monomer was emulsion-polymerized using potassium stearate to obtain a rubber-reinforced styrene resin latex.
After adding to a 0.3% dilute sulfuric acid aqueous solution at 90 ° C. and agglomerating, neutralizing with an aqueous sodium hydroxide solution, washing, dehydration, and drying steps are performed, and the emulsifier component rate is 0.22% and the moisture content is 2.3%. A graft copolymer (A-7) was prepared. The graft rate was 42%.

Reference Example 2 Production of Copolymer (B) (1) Preparation of Copolymer (B-1) A slurry obtained by suspension polymerization of a monomer mixture comprising 70 parts of styrene and 30 parts of acrylonitrile was washed and washed. Through the dehydration and drying step, a copolymer (B-1) having an oligomer ratio of 0.45% and a moisture ratio of 0.4% was prepared.

(2) Preparation of copolymer (B-2) The slurry obtained by suspension polymerization of a monomer mixture consisting of 23 parts of styrene, 8 parts of acrylonitrile and 69% of methyl methacrylate was subjected to washing, dehydration and drying steps. Then, a copolymer (B-2) having an oligomer ratio of 0.49% and a moisture ratio of 0.4% was prepared.

(3) Preparation of copolymer (B-3) A monomer mixture consisting of 70 parts of styrene and 30 parts of acrylonitrile was emulsion-polymerized using potassium stearate to obtain a styrene resin latex. After adding and aggregating in 0.3% dilute sulfuric acid aqueous solution, neutralizing with sodium hydroxide aqueous solution, and passing through washing, dehydration and drying steps, the emulsifier component rate is 0.22%, the oligomer rate is 0.35%, the moisture content A 0.4% graft copolymer (B-3) was prepared.

(4) Preparation of copolymer (B-4) A monomer mixture consisting of 70 parts of styrene and 30 parts of acrylonitrile was bulk polymerized to give a copolymer having an oligomer ratio of 0.70% and a moisture ratio of 0.1% ( B-4) was prepared.

(5) Preparation of copolymer (B-5) A monomer mixture consisting of 70 parts of styrene and 30 parts of acrylonitrile was bulk polymerized to give a copolymer having an oligomer ratio of 1.08% and a moisture ratio of 0.1% ( B-5) was prepared.

(6) Preparation of copolymer (B-6) A slurry obtained by suspension polymerization of a monomer mixture composed of 70 parts of styrene and 30 parts of acrylonitrile was subjected to washing, dehydration, and drying steps to obtain an oligomer ratio of 0. A copolymer (B-6) having a moisture content of 45% and a moisture content of 1.8% was prepared.

Reference Example 3 Polycarbonate (C)
(1) Polycarbonate (C-1): “Taflon A2200” manufactured by Idemitsu Petrochemical Co., Ltd.
(2) Polycarbonate (C-2): “Taflon A1700” manufactured by Idemitsu Petrochemical Co., Ltd.
Reference Example 4 Phosphorus stabilizer (D)
(1) Phosphorus stabilizer (D-1)
MARK517 (phenyl diisodecyl phosphite) manufactured by Asahi Denka Kogyo Co., Ltd.
Molecular weight 439 Boiling point 240 ° C
(2) Phosphorus stabilizer (D-2)
MARK135A (diphenylisodecyl phosphite) manufactured by Asahi Denka Kogyo Co., Ltd.
Molecular weight 375 Boiling point 230 ° C
(3) Phosphorus stabilizer (D-3)
Trimethyl phosphate (molecular weight 140, boiling point 190 ° C) is used. The above-mentioned various polymers and stabilizers are mixed at the blending ratio shown in Table 1, and the barrel temperature is set to 240 ° C with a twin screw extruder and melt extrusion is performed. To obtain a thermoplastic resin composition. Next, using the obtained pellets, injection molding was performed at a molding temperature of 240 ° C. and a mold temperature of 60 ° C. to prepare test pieces for various evaluations. The test results are shown in Tables 2 to 3.

  From Examples 1 to 12, the thermoplastic resin composition of the present invention contains a polycarbonate characterized by excellent resistance to moisture and heat aging and heat stability to maintain the impact resistance, molding processability and appearance during production. It can be seen that this is a thermoplastic resin composition.

  On the other hand, it turns out that Comparative Examples 1-9 has not yet reached the point where the problem of the present invention is solved.

  In Comparative Example 1, since the emulsifier component ratio of the graft copolymer (A) remains more than the specified range, the wet heat aging characteristics are poor. The rate of change of MFR is high, and there is a concern that the moldability may change if it is used after being left in a high temperature / high humidity environment.

  Since Comparative Example 2 uses a metal salt during solidification of the graft copolymer (A), the wet heat aging characteristics are poor as in Comparative Example 1. Furthermore, the heat stability is poor, and a molded article with a good appearance cannot be obtained.

  In Comparative Examples 3 and 5, since the moisture content of the graft copolymer (A) and copolymer (B) is high, the impact strength before environmental treatment is low, and the appearance and impact strength after heat retention treatment are maintained. The rate is also low.

  In Comparative Example 4, since the oligomer component content of the copolymer (B) remains more than the specified range, the wet heat aging characteristics are poor. Furthermore, the heat stability is poor, and a molded article with a good appearance cannot be obtained.

  In Comparative Example 6, since the viscosity average molecular weight of the polycarbonate (C) is lower than the specified range, wet heat aging characteristics are poor.

  In Comparative Example 7, since the phosphorus stabilizer (D) has a low molecular weight and a low boiling point, the function of the phosphorus stabilizer is lowered and the wet heat aging characteristics are poor. Furthermore, the appearance and impact strength retention after the heat retention treatment are lowered.

  In Comparative Example 8, since the graft copolymer (A) is added beyond the specified range, the heat stability is poor, and a molded article having a good appearance cannot be obtained.

  Comparative Example 9 has poor wet heat aging characteristics because no phosphorus stabilizer (D) is added. Furthermore, the appearance and impact strength retention after the heat retention treatment are lowered.

Claims (6)

In the presence of the rubber polymer (a), an aromatic vinyl monomer (a1), a vinyl cyanide monomer (a2), and another monomer (a3) copolymerizable therewith are contained. Emulsion polymerization of a vinyl monomer mixture using a higher fatty acid ester salt emulsifier, and after acid coagulation, the emulsifier component is removed to 0.3% or less based on the polymer. The following graft copolymer (A) 5-40 parts by weight aromatic vinyl monomer (b1), vinyl cyanide monomer (b2) and other monomers copolymerizable therewith (b3) A copolymer containing a vinyl monomer mixture containing 0.1% or less of an oligomer (dimer or trimer) component prepared to 1.0% or less of the polymer. Polymer (B) 0 to 40 parts by weight Polycarbonate resin having a viscosity average molecular weight of 17,000 or more (C Phosphorus stabilizer (D) comprising 10 to 90 parts by weight, having a molecular weight of 200 to 1000 and a boiling point of 200 ° C. or higher with respect to (A) + (B) + (C) = 100 parts by weight. A thermoplastic resin composition comprising a polycarbonate produced to be 1 to 5 parts by weight. The thermoplastic resin composition according to claim 1, wherein the acid used for acid coagulation of the graft copolymer (A) is sulfuric acid. The thermoplastic resin composition according to claim 1, wherein the vinyl copolymer (B) is produced by a suspension polymerization method. The heat according to claim 1, wherein the vinyl copolymer (B) is produced by an emulsion polymerization method, and the emulsifier component is removed to 0.3% or less with respect to the polymer. Plastic resin composition.   The thermoplastic resin composition according to claim 1, wherein the phosphorus stabilizer (D) is phenyl alkyl phosphite.   The thermoplastic resin composition according to claim 1, wherein the phosphorus stabilizer (D) is diphenylisodecyl phosphite.