JPH11293102A - Thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermoplastic resin composition excellent in molding characteristics, fatigue strength, impact strength, heat resistance by making the composition include a polycarbonate resin and a specific graft copolymer in a specific ratio. SOLUTION: This thermoplastic resin composition comprises (A) 15 to 80 pts.wt. of polycarbonate resins, (B) 10 to 50 pts.wt. of graft copolymer obtained by polymerizing 30 to 95 wt.% of monomers including vinyl cyanide monomers and vinyl aromatic monomers as the essential constituents in the presence of 5 to 70 wt.%. of a rubber like polymers obtained by polymerizing an aliphatic conjugated diene monomer as the essential constituent, (C) 5 to 40 pts.wt. of the first copolymer obtained by polymerizing 10 to 40% of vinyl cyanide monomers, 60 to 90% of vinyl aromatic monomers and 0 to 40% of other vinyl monomers copolymerizable with these monomers, having molecular weight distribution of 1.0 to 2.0 and (D) 5 to 25 pts.wt. of the second copolymers obtained by polymerizing 15 to 35% of vinyl cyanide monomers, 65 to 85% of vinyl aromatic monomers and 0 to 40% of other vinyl monomers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a thermoplastic resin composition (polycarbonate / ABS alloy resin composition) having excellent moldability and excellent fatigue strength, impact resistance and heat resistance.

[0002]

2. Description of the Related Art Conventionally, rubber-modified thermoplastic resin compositions represented by ABS resins have been widely used as thermoplastic resin compositions having excellent impact resistance and moldability.
However, since ABS resin lacks heat resistance, use at high temperatures is limited. Therefore, various methods for improving the heat resistance of the ABS resin have been proposed.

[0003] For example, Japanese Patent Publication No. 38-15225 discloses a resin composition containing an ABS resin and a polycarbonate resin. Japanese Patent Application Laid-Open No. 64-202
No. 60 discloses a polycarbonate modified with a rubber-modified thermoplastic resin and two types of copolymers (Mn) having a specific range of molecular weight.
4.5 × 10 ^{4 to} 6.5 × 10 ⁴ , Mw 10 × 10 ⁴ to 15.
5 × 10 ⁴ , Mw / Mn 2.0 to 3.0, Mn 2.5 × 1
^{0 4 ~3.5 × 10 4, Mw5} × 10 4 ~7 × 10 4, Mw
/ Mn 2.0-3.0) to disclose a polycarbonate / ABS alloy resin having improved moldability.

[0004]

SUMMARY OF THE INVENTION Polycarbonate / A
Although the heat resistance and the impact resistance of the BS alloy resin can be improved by increasing the ratio of the polycarbonate, the fluidity of the resin at a high temperature, that is, the moldability decreases. Conversely, if the proportion of polycarbonate is reduced or a copolymer having a relatively low molecular weight is blended, the moldability becomes better, but the fatigue strength, impact resistance, and heat resistance decrease. This point has narrowed the use of the polycarbonate / ABS alloy resin.

Recently, polycarbonate / ABS has been used to increase the size, thickness, and complexity of resin molded products.
Demands for alloy resins are becoming more stringent. Therefore, attempts have been made to improve various physical properties such as heat resistance, impact resistance, molding workability, and rigidity of the resin. However, some applications require a stricter balance, and in such applications, satisfactory physical properties have not yet been obtained. That is, when the ratio of polycarbonate is reduced or a copolymer having a relatively low molecular weight is blended for the purpose of improving the moldability in accordance with the prior art, there is a limit in balancing various physical properties.

An object of the present invention is to provide a thermoplastic resin composition (polycarbonate / ABS alloy resin) which is excellent in balance of various physical properties, particularly excellent in moldability, and excellent in fatigue strength, impact resistance and heat resistance. It is in.

[0007]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, have found that a polycarbonate resin, a rubber-modified thermoplastic resin, and two types of copolymers whose molecular weight distributions are specified. By mixing in a specific ratio with, excellent moldability, fatigue strength, impact resistance,
The inventors have found that a polycarbonate / ABS alloy resin composition having excellent heat resistance can be obtained, and have completed the present invention.

That is, the present invention provides a rubbery polymer 5 obtained by polymerizing (A) 15 to 80 parts by weight of a polycarbonate resin and (B) a monomer having an aliphatic conjugated diene monomer as an essential component. 30 to 95% by weight of a monomer having a vinyl cyanide-based monomer and an aromatic vinyl-based monomer as an essential component in the presence of 70 to 70% by weight (total amount of the monomer and the rubbery polymer) (100% by weight) of the graft copolymer.
50 parts by weight, (C) vinyl cyanide monomer 10 to 40
% By weight, 60 to 90% by weight of an aromatic vinyl monomer and 0 to 40% by weight of another vinyl monomer copolymerizable therewith (the vinyl cyanide monomer and the aromatic vinyl monomer alone). A total of 100% by weight of the monomer and the other vinyl monomer), and has a number average molecular weight Mn of 4.5 ×.
10 ^{4 to} 9.5 × 10 ⁴ , weight average molecular weight Mw of 8.5 × 1
0 ⁴ in the range of ~18.5 × 10 ^4, and the first copolymer 5-40 parts by weight of a molecular weight distribution Mw / Mn is in the range of less than 1.0 to 2.0, and, (D ) 15-35% by weight of vinyl cyanide monomer, 65-aromatic vinyl monomer
85% by weight and 0 to 40% by weight of another vinyl monomer copolymerizable therewith (the vinyl cyanide monomer, the aromatic vinyl monomer and the other vinyl monomer). Total 10
0% by weight), and has a number average molecular weight Mn of 2.5 × 10 ⁴ to 3.5 × 10 ⁴ and a weight average molecular weight Mw of 4.5 × 10 ^{4 to} 6.5 × 5 to 25 parts by weight of a second copolymer having a molecular weight distribution Mw / Mn of 1.0 to less than 2.0 in a range of 10 ⁴ [total of components (A) to (D)] 100 parts by weight].

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below.

In the present invention, the component (A) is used
As the polycarbonate resin (A), various polycarbonate resins obtained by conventionally known various production methods can be used. Generally, a polycarbonate-based resin obtained by reacting a dihydroxy or polyhydroxy compound with phosgene or a carbonic acid diester is exemplified.

In particular, polycarbonate resins obtained from dihydroxydiarylalkanes are preferred. The molecules of the resin may be branched. The dihydroxyarylalkane used here may have an alkyl group, a chlorine atom, a bromine atom, or the like at the position ortho to the hydroxy group bonded to the aromatic ring. Preferred specific examples of the dihydroxydiarylalkane include 4,4′-dihydroxy-2,2′-diphenylpropane [that is, bisphenol A], tetramethylbisphenol A, bis (4-hydroxyphenyl) -p-diisopropylbenzene, and the like. No.

The branched polycarbonate resin can be produced, for example, by substituting a part (about 0.2 to 2 mol%) of a dihydroxy compound to be used with a polyhydroxy compound. Specific examples of the polyhydroxy compound include 1,4-bis (4 ′, 4,2-dihydroxytriphenylmethyl) -benzene, phloroglucinol,
Dimethyl-2,4,6-tri (4-hydroxyphenyl)
-Heptene, 4,6-dimethyl-2,4,6-tri (4-
(Hydroxyphenyl) -heptane, 1,3,5-tri (4
-Hydroxyphenyl) -benzene, 1,1,1-tri (4-hydroxyphenyl) -ethane, 2,2-bis [4,4 '-(4,4'-dihydroxyphenyl) cyclohexyl] propane, and the like. .

The molecular weight of the polycarbonate resin (A) is not particularly limited, and may be appropriately selected as desired.

In the resin composition of the present invention, (A) based on a total of 100 parts by weight of the components (A) to (D).
The amount of the component is 15 to 80 parts by weight, preferably 3 to 80 parts by weight.
0 to 70 parts by weight. If the amount is less than 15 parts by weight, the impact resistance of the resin composition will be insufficient, and if it exceeds 80 parts by weight, the moldability will be poor.

In the present invention, the component (B) is used as
The graft copolymer (B) is a rubbery polymer 5 obtained by polymerizing a monomer having an aliphatic conjugated diene monomer as an essential component.
In the presence of about 70% by weight, a monomer containing a vinyl cyanide monomer and an aromatic vinyl monomer as essential components
It is a graft copolymer (that is, an ABS resin) obtained by polymerizing 95% by weight.

The aliphatic conjugated diene used here includes:
Examples include 1,3-butadiene, isoprene, chloroprene, and the like. In particular, 1,3-butadiene is preferred from the viewpoint of impact resistance. The amount of the aliphatic diene-based monomer is preferably from 30 to 100 parts by weight based on 100 parts by weight of the total of the monomers used for producing the rubbery polymer. When the amount is 30 parts by weight or more, a graft copolymer (B) having good impact resistance can be obtained.

When an aliphatic diene monomer is used in combination with another monomer as a monomer used for producing the rubbery polymer, the other monomer may be a diene monomer. Various copolymerizable monomers can be used. Specific examples thereof include vinyl cyanide monomers such as acrylonitrile and methacrylonitrile; aromatic vinyl monomers such as styrene, α-methylstyrene, p-chlorostyrene and p-methylstyrene; methyl acrylate And unsaturated carboxylic esters such as ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, n-hexyl acrylate, methyl methacrylate and ethyl methacrylate;

As a method for producing the rubber-like polymer, various conventionally known methods can be employed. For example, a method in which solution polymerization is carried out using a Ziegler-based catalyst and this is homogenized with an emulsifier and water and emulsified and dispersed, or a method in which emulsion polymerization is used, and the like can be mentioned. In particular, the dispersion particle diameter, molecular weight, gel content, ease of controlling the degree of swelling of the rubber-like polymer, the degree of freedom for producing a high-performance graft copolymer (B), and the like, Emulsion polymerization is optimal.

As the method for producing the graft copolymer (B), that is, the graft polymerization method, various conventionally known methods can be adopted. For example, emulsion polymerization, suspension polymerization, solution polymerization, bulk polymerization, or graft polymerization can be used in combination of two or more of these. Among them, the emulsion polymerization is the most suitable for the graft polymerization in view of the fact that the emulsion polymerization is the most suitable method for producing the rubbery polymer as described above. For example, a rubbery polymer obtained by emulsion polymerization may be further polymerized by adding a monomer mixture for grafting.

The thus-obtained graft copolymer (B) can be recovered as a powdery solid by coagulation with an acid or salt, which is a conventional method for recovering a polymer from latex, and a drying step.

The monomers to be graft-polymerized to the rubbery polymer include vinyl cyanide monomers and aromatic vinyl monomers as essential components. Specific examples of the vinyl cyanide monomer include acrylonitrile, methacrylonitrile, vinylidene cyanide, and the like. In particular, acrylonitrile is preferred. Specific examples of the aromatic vinyl monomer include vinyl toluenes such as styrene, α-methylstyrene and p-methylstyrene, halogenated styrenes such as p-chlorostyrene, pt-butylstyrene, and dimethylstyrene. And vinyl naphthalenes. Especially,
Styrene and α-methylstyrene are preferred.

As monomers for graft polymerization, in addition to vinyl cyanide monomers and aromatic vinyl monomers, other monomers can be used in combination, if desired.
Specific examples thereof include unsaturated carboxylic acid ester monomers such as methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, n-hexyl acrylate, methyl methacrylate, and ethyl methacrylate. Unsaturated dicarboxylic anhydrides such as maleic anhydride, itaconic anhydride and citraconic anhydride;
Imide compounds of unsaturated dicarboxylic acids such as N-methylmaleimide, N-butylmaleimide, N-phenylmaleimide and N-cyclohexylmaleimide;
These may be used alone or in combination of two or more.

The proportion of the monomer for graft polymerization is usually in the ratio of vinyl cyanide monomer / aromatic vinyl monomer /
Other monomers (weight ratio) = 10 to 50/50 to 90 /
0-40, preferably 15-45 / 45-85 / 0-2
0.

Further, glycidyl methacrylate, methacrylic acid,
Acrylic acid, methacrylamide, 2-hydroxyethyl methacrylate, polyethylene glycol monomethacrylate and the like can be used together in an amount of 20% by weight or less, preferably 15% by weight or less based on 100% by weight of the total of monomers for graft polymerization. is there.

In the production of the graft copolymer (B),
The ratio of the rubber-like polymer and the monomer for graft polymerization is as follows: rubber-like polymer / monomer mixture (weight ratio) = 5 to 70/30 to
95, preferably 10-65 / 35-90. When the amount of the rubbery polymer is less than 5% by weight, the proportion of the rubbery polymer in the resin is inevitably low, and the impact resistance is reduced. On the other hand, if it exceeds 70% by weight, the graft ratio to the rubber-like polymer becomes low, and the dispersion of the rubber-like polymer in the resin becomes insufficient, so that impact resistance cannot be exhibited.

In the resin composition of the present invention, (B) based on a total of 100 parts by weight of the components (A) to (D)
The amount of the component is 10 to 50 parts by weight, preferably 1 to 50 parts by weight.
5 to 40 parts by weight. If the amount is less than 10 parts by weight, the impact resistance is poor, and if it exceeds 50 parts by weight, the moldability is poor.

In the present invention, used as the component (C)
The first copolymer (C) is a vinyl cyanide monomer 10
-40% by weight, aromatic vinyl monomer 60-90% by weight
And other vinyl monomers 0 to 4 copolymerizable therewith.
It is a copolymer obtained by polymerizing 0% by weight.

Specific examples of the vinyl cyanide-based monomer, aromatic vinyl-based monomer, and other copolymerizable vinyl-based monomers used herein are exemplified in the description of the graft copolymer (B). The same ones as mentioned above can be mentioned.

The first copolymer (C) has a number average molecular weight Mn of 4.5 × 10 ^{4 to} 9.5 × 10 ⁴ and a weight average molecular weight Mw of 8.5 × 10 ^{4 to} 18.5 × 10 ⁴ , and the molecular weight distribution Mw / Mn is in the range of 1.0 or more and less than 2.0. When the molecular weight or the molecular weight distribution is out of the above range, the obtained resin composition is inferior in at least one of moldability, fatigue strength, impact resistance and heat resistance. In particular, when Mw / Mn is 2.0 or more, problems occur in points such as moldability and impact resistance. Preferably,
Number average molecular weight Mn is 5.0 × 10 ^{4 to} 8.5 × 10 ⁴ , weight average molecular weight Mw is 9.0 × 10 ^{4 to} 16 × 10 ⁴ , and molecular weight distribution Mw / Mn is 1.5 or more and 1.9 or less. Range.

As a method for producing the first copolymer (C), various conventionally known methods can be employed. For example,
The above monomer mixture may be copolymerized by a method such as emulsion polymerization, suspension polymerization, solution polymerization, or bulk polymerization.

In the resin composition of the present invention, based on 100 parts by weight of the total of the components (A) to (D), (C)
The amount of the component is 5 to 40 parts by weight, preferably 10 to 10 parts by weight.
-30 parts by weight. If the amount is less than 5 parts by weight, the fatigue strength will be insufficient, and if it exceeds 40 parts by weight, the impact resistance will be poor.

In the present invention, used as component (D)
The second copolymer (D) is a vinyl cyanide monomer 15
To 35% by weight, aromatic vinyl monomer 65 to 85% by weight
And other vinyl monomers 0 to 4 copolymerizable therewith.
It is a copolymer obtained by polymerizing 0% by weight.

Specific examples of the vinyl cyanide-based monomer, aromatic vinyl-based monomer, and other copolymerizable vinyl-based monomers used herein are exemplified in the description of the graft copolymer (B). The same ones as mentioned above can be mentioned.

The second copolymer (D) has a number average molecular weight Mn of 2.5 × 10 ⁴ to 3.5 × 10 ⁴ and a weight average molecular weight Mw of 4.5 × 10 ^{4 to} 6.5 × 10 ⁴ , and the molecular weight distribution Mw / Mn is in the range of 1.0 or more and less than 2.0. As described above, the second copolymer (D) is a component having a relatively small molecular weight and significantly improving the moldability while ensuring fatigue strength, impact resistance, and heat resistance. When the molecular weight or the molecular weight distribution is out of the above range, the obtained resin composition is inferior in at least one of moldability, fatigue strength, impact resistance and heat resistance. In particular, Mw
If / Mn is 2.0 or more, problems arise in terms of moldability, impact resistance, and the like. Preferably, the number average molecular weight Mn
Range but ^{3.0 × 10 4 ~3.5 × 10 4} , weight average molecular weight Mw of ^{5.0 × 10 4 ~6.0 × 10 4} , a molecular weight distribution Mw / Mn of 1.5 to 1.9 It is.

As the method for producing the second copolymer (D), various conventionally known methods can be employed. For example,
The above monomer mixture may be copolymerized by a method such as emulsion polymerization, suspension polymerization, solution polymerization, or bulk polymerization.

In the resin composition of the present invention, (D) based on a total of 100 parts by weight of the components (A) to (D)
The amount of the component is 5 to 25 parts by weight. This compounding amount is 5
If the amount is less than 25 parts by weight, the molding processability of the resin composition becomes insufficient, and if it exceeds 25 parts by weight, the impact resistance becomes poor.

The resin composition of the present invention is a composition containing the above-described components (A) to (D) as main components, and contains only the components (A) to (D). However, various stabilizers, plasticizers, lubricants, metal soaps, antistatic agents and the like can be added according to the purpose.
For such mixing, for example, a device such as a Henschel mixer, a Banbury mixer, an extruder, or a heating roll is used.

When the resin composition of the present invention is used, for example,
Useful molded articles can be obtained by various molding methods such as injection molding and extrusion molding.

[0039]

The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these. In the following description,% and parts are based on weight unless otherwise specified.

Various physical properties in Examples and Comparative Examples were measured by the following methods.

(1) Izod impact strength Measured at 23 ° C. according to ASTM D256 with a 1 / 8-inch notch of a test piece.

(2) Short shot pressure Shown as a percentage of the maximum pressure (2,000 kgf / cm ² ) of a molding machine that can be used when a square plate having a thickness of 3 mm and a size of 100 mm × 100 mm is molded at a cylinder temperature of 260 ° C. Was. This value is an index of the fluidity of the resin.

(3) Heat deformation temperature Measured under a load of 18.6 kg in accordance with ASTM D648.

(4) Fatigue strength According to ASTM D-671, stress 150 kg / cm
^{In step 2,} the number of times to reach destruction was obtained.

<Production Example 1 Graft Copolymer (B-1)
Production> 10 liter glass reactor, 150 parts of deionized water (including water in latex) 60 parts of polybutadiene latex (weight average particle diameter 280 nm (solid content)) 60 parts 0.5 parts of potassium rosinate 0.3 parts of dextrose, 0.1 part of sodium pyrophosphate, 0.005 part of ferrous sulfate and heptahydrate were charged, and the internal temperature was raised to 65 ° C. A mixture of 13 parts of acrylonitrile, 27 parts of styrene, 0.3 parts of t-dodecylmercaptan, and 0.18 parts of cumene hydroperoxide was added dropwise thereto over 150 minutes to initiate polymerization. After dropping, 0.1 part of cumene hydroperoxide was added, and the mixture was kept for 1 hour and cooled. The obtained latex was added to twice the amount of the latex in a 0.4% aqueous sulfuric acid solution (65 ° C.), and then the temperature was raised to 90 ° C. to coagulate. After repeated washing and dehydration well, drying was finally performed to obtain a graft copolymer (B-1) as a milky white powder.

<Production Example 2 Graft Copolymer (B-2)
Preparation of> 10 liter glass reactor: ・ 145 parts of deionized water (including water in latex) ・ 45 parts of polybutadiene latex (weight average particle size 280 nm (solid content)) ・ 1 part of potassium rosinate ・ Dextrose 0.3 part ・ acrylonitrile 9 parts ・ styrene 21 parts ・ t-dodecylmercaptan 0.2 parts ・ cumene hydroperoxide 0.12 parts were charged, and the internal temperature was raised to 60 ° C. To this, an aqueous solution consisting of 0.1 parts of sodium pyrophosphate, 0.005 parts of ferrous sulfate and heptahydrate, and 5 parts of water was added to initiate polymerization. After the heat generated by the polymerization disappeared, the internal temperature of the reaction solution raised by the heat generated by the polymerization was cooled to 65 ° C. It was fed into the reactor over a period of minutes. Twenty minutes after the start of feeding, 0.2 parts of cumene hydroperoxide was added, and polymerization was started again. After the completion of the dropwise addition, the mixture was kept for 1 hour and cooled. The obtained latex was added to twice the amount of the latex in a 0.5% sulfuric acid aqueous solution (75 ° C.) to coagulate. After repeated washing and dehydration, the graft copolymer (B-2) which is finally dried and is a milky white powder
I got

<Production Example 3 Production of Copolymer (C-1)>
In a 10 liter SUS autoclave: ・ 150 parts of water ・ 30 parts of acrylonitrile ・ 70 parts of styrene ・ 0.15 parts of azobisisobutyronitrile ・ 0.5 parts of t-dodecylmercaptan ・ 0.4 parts of calcium phosphate ・ 0.4 parts of polyvinyl alcohol Two parts were charged and stirred vigorously. After confirming the dispersion state in the system, the temperature was raised to 75 ° C. and polymerization was performed for 2 hours. Thereafter, the internal temperature was raised to 110 ° C. and maintained for 20 minutes to complete the reaction. After cooling, dehydration, washing and drying were performed to obtain a white granular copolymer (C-1). The copolymer (C-1) had a number average molecular weight Mn of 58,000 and a weight average molecular weight Mw of 107.
000, molecular weight distribution Mw / Mn was 1.84.

<Production Example 4 Production of Copolymer (C-2)>
In a 10 liter SUS autoclave, ・ 150 parts of water ・ 25 parts of acrylonitrile ・ 55 parts of styrene ・ 20 parts of methyl methacrylate ・ 0.17 parts of azobisisobutyronitrile ・ 0.45 parts of t-dodecyl mercaptan ・ 0.4 parts of calcium phosphate Part-0.2 part of polyvinyl alcohol was charged and stirred vigorously. After confirming the dispersion state in the system, the temperature was raised to 75 ° C. and polymerization was performed for 2 hours. Thereafter, the internal temperature was raised to 110 ° C. and maintained for 20 minutes to complete the reaction. After cooling, dehydration, washing and drying were performed to obtain a white granular copolymer (C-2). The number average molecular weight Mn of this copolymer (C-2) is 54,000, and the weight average molecular weight Mw is 930.
The molecular weight distribution Mw / Mn was 1.72.

<Comparative Production Example 1 Production of Copolymer (C-3)> In a 10-liter SUS autoclave, 200 parts of water 0.6 parts of dextrose 0.2 parts of sodium sulfate 0.2 ferrous sulfate 0.003 parts of heptahydrate, 0.12 parts of sodium pyrophosphate, and 2 parts of potassium rosinate were charged, and the internal temperature was raised to 60 ° C. To this, 0.05 part of cumene hydroperoxide was added, and after holding for 10 minutes, a mixture consisting of 20 parts of acrylonitrile, 80 parts of styrene, 0.25 part of cumene hydroperoxide, 0.2 part of t-dodecyl mercaptan Was added dropwise over 120 minutes to initiate polymerization. After the completion of the dropwise addition, 0.05 parts of cumene hydroperoxide was added, the internal temperature was raised to 80 ° C., and the temperature was held for 1 hour to cool. The latex thus obtained was used in the same amount as the latex.
It was added to a 5% aqueous sulfuric acid solution (90 ° C.) and then heated to 99 ° C. for coagulation. This was dehydrated, washed and dried to obtain a copolymer (C-3). The number average molecular weight Mn of this copolymer (C-3) was 66,000, and the weight average molecular weight Mw was 1
54000, molecular weight distribution Mw / Mn was 2.33.

<Production Example 5 Production of Copolymer (D-1)>
In a 10-liter SUS autoclave: ・ 150 parts of water ・ 25 parts of acrylonitrile ・ 75 parts of styrene ・ 0.18 parts of azobisisobutyronitrile ・ 0.81 part of t-dodecylmercaptan ・ 0.4 parts of calcium phosphate ・ 0.8 parts of polyvinyl alcohol Two parts were charged and stirred vigorously. After confirming the dispersion state in the system, the temperature was raised to 75 ° C. and polymerization was performed for 2 hours. Thereafter, the internal temperature was raised to 110 ° C. and maintained for 20 minutes to complete the reaction. After cooling, dehydration, washing and drying were performed to obtain a white granular copolymer (D-1). The number average molecular weight Mn of this copolymer (D-1) is 31,000, and the weight average molecular weight Mw is 560.
The molecular weight distribution Mw / Mn was 1.83.

<Comparative Production Example 2 Production of Copolymer (D-2)> In a 10-liter SUS autoclave, 200 parts of water 0.6 parts of dextrose 0.2 parts of sodium sulfate 0.2 ferrous sulfate 0.003 parts of heptahydrate ・ 0.12 parts of sodium pyrophosphate ・ 2 parts of potassium rosinate were charged and the internal temperature was raised to 60 ° C. To this, 0.05 parts of cumene hydroperoxide was added, After holding for 10 minutes, a mixture consisting of 20 parts of acrylonitrile, 80 parts of styrene, 0.6 part of cumene hydroperoxide, and 1.6 parts of t-dodecylmercaptan was dropped over 120 minutes to initiate polymerization. After dropping, cumene hydroperoxide 0.0
5 parts were added, the internal temperature was raised to 80 ° C., and the temperature was maintained for 1 hour to cool. The latex thus obtained was used in the same amount as the latex.
It was added to a 5% aqueous sulfuric acid solution (90 ° C.) and then heated to 99 ° C. for coagulation. This was dehydrated, washed and dried to obtain a copolymer (D-2). The copolymer (D-2) had a number average molecular weight Mn of 26,000 and a weight average molecular weight Mw of 61.
000, molecular weight distribution Mw / Mn was 2.34.

<Examples 1 to 7 and Comparative Examples 1 to 8>
(A) polycarbonate resin [(A-1): trade name NOVAREX 7022A manufactured by Mitsubishi Chemical Corporation], (B) graft copolymer, (C) copolymer, (D) obtained in each production example
The copolymer was mixed at a ratio shown in Table 1 with a Henschel mixer, and shaped at a cylinder temperature of 260 ° C. using a twin-screw extruder to produce a pellet-shaped resin composition. The evaluation results of each resin composition are also shown in Table 1.

[0053]

[Table 1] As is clear from the results shown in Table 1, each of the resin compositions of Examples 1 to 7 satisfying the various conditions defined in the present invention is excellent in molding workability, fatigue strength, impact resistance, and heat resistance. I was On the other hand, each of the resin compositions of Comparative Examples 1 to 8, which did not satisfy the conditions specified in the present invention, was insufficient in any property, particularly, in the moldability of a molded product.

[0054]

According to the present invention described above, it is possible to provide a thermoplastic resin composition which is excellent in balance of various physical properties, particularly excellent in moldability and fatigue strength, and excellent in impact resistance and heat resistance.

Claims (1)

[Claims] (A) a polycarbonate resin 15 to 8
0 parts by weight, (B) a vinyl cyanide-based monomer and an aromatic compound in the presence of 5 to 70% by weight of a rubbery polymer obtained by polymerizing a monomer having an aliphatic conjugated diene-based monomer as an essential component Graft copolymer obtained by polymerizing 30 to 95% by weight of a monomer having a vinyl group monomer as an essential component (total amount of 100% by weight of the monomer and the rubbery polymer) (C) 10 to 40% by weight of a vinyl cyanide monomer, 60 to 90% by weight of an aromatic vinyl monomer and 0 to 40% by weight of another vinyl monomer copolymerizable therewith ( A copolymer obtained by polymerizing the vinyl cyanide-based monomer, the aromatic vinyl-based monomer and the other vinyl-based monomer (100% by weight in total), and having a number average molecular weight Mn of 4. 5 × 10 ^{4 to} 9.5
× 10 ⁴ , weight average molecular weight Mw of 8.5 × 10 ^{4 to} 18.5
The first copolymers 5 to 4 having a molecular weight distribution Mw / Mn of 1.0 to less than 2.0 in a range of × 10 ^4.
0 parts by weight, and (D) 15 to 35% by weight of a vinyl cyanide monomer, 65 to 85% by weight of an aromatic vinyl monomer and 0 to another vinyl monomer copolymerizable therewith. 40% by weight (total 100% by weight of the vinyl cyanide-based monomer, the aromatic vinyl-based monomer and the other vinyl-based monomer), and a number average molecular weight Mn is 2.5 × 10 ⁴ to 3.5
× 10 ⁴ , weight average molecular weight Mw of 4.5 × 10 ^{4 to} 6.5 ×
10 ⁴ and the molecular weight distribution Mw / Mn is 1.
Second copolymer 5 to 25 in the range of 0 to less than 2.0
A thermoplastic resin composition comprising parts by weight [total 100 parts by weight of components (A) to (D)].