JPS639544B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a thermoplastic resin composition having excellent heat resistance and impact resistance. More specifically, the present invention relates to a thermoplastic resin composition containing a maleimide-based graft copolymer obtained by grafting a copolymer having maleimide units onto a rubber-like polymer. Many studies have been conducted to improve the heat resistance of styrenic resins. For example, acrylonitrile-butadiene-styrene copolymer (ABS
Copolymers using α-methylstyrene as part or all of styrene have been studied in order to improve the heat resistance of resins), but α-methylstyrene copolymers do not have sufficient thermal stability. However, if the content of α-methylstyrene is increased in an attempt to improve the heat distortion temperature, there is a drawback that the thermal decomposition temperature of the copolymer decreases. On the other hand, a maleimide-based graft copolymer made by imidizing a copolymer of styrene and maleic anhydride has a high heat distortion temperature and thermal decomposition temperature. It has been proposed to obtain a resin composition with excellent thermal stability by blending the
3642949 and Japanese Patent Application Laid-Open No. 125242/1983). However, this composition does not have sufficient impact resistance, and when the amount of graft copolymer blended is increased in order to satisfy the impact resistance, there is a problem that the heat distortion temperature is significantly lowered. Therefore, the present inventors conducted extensive research with the aim of obtaining a thermoplastic molding material with a balance between heat resistance, represented by heat distortion temperature, and impact resistance, represented by impact strength. By blending a specific graft copolymer and vinyl polymer with a maleimide graft copolymer grafted with a copolymer having maleimide units,
The inventors have discovered that the above object can be effectively achieved and have arrived at the present invention. That is, the present invention comprises (A) 50 to 80 parts by weight of an aromatic vinyl monomer in the presence of 5 to 40 parts by weight of a rubbery polymer;
A graft copolymer obtained by graft polymerizing 60 to 95 parts by weight of a monomer mixture consisting of 5 to 50% by weight of maleic anhydride and 0 to 30% by weight of a vinyl monomer copolymerizable with maleic anhydride is prepared by adding ammonia or Aromatic vinyl monomer and vinyl cyanide monomer in the presence of 10 to 60 parts by weight of a maleimide graft copolymer obtained by reacting with a primary amine and 20 to 80 parts by weight of (B) rubbery polymer. Graft copolymer 5 ~ obtained by graft polymerizing 80 ~ 20% by weight of a monomer mixture consisting of
(A), (B ) and (C) in a total amount of 100 parts by weight. In the present invention, maleimide-based graft copolymer
The rubbery polymer that is a component of (A) and the graft copolymer (B) is a rubbery polymer with a glass transition temperature of -10°C or lower, such as polybutadiene rubber, acrylonitrile-butadiene copolymer, etc. Examples include diene rubbers such as composite rubber (NBR) and styrene-butadiene copolymer rubber (SBR), acrylic rubbers such as polybutyl acrylate and polypropyl acrylate, and ethylene-propylene-diene rubber (EPDM). However, the ratio of the rubbery polymer to the monomer mixture consisting of the aromatic vinyl monomer, maleic anhydride and other vinyl monomers in the maleimide graft copolymer (A) is important; It is necessary to polymerize from 95 to 60 parts by weight, in particular from 90 to 65 parts by weight, of the above monomer mixture in the presence of from 5 to 40 parts by weight, in particular from 10 to 35 parts by weight, of the rubbery polymer. If the proportion of the rubbery polymer is less than 5 parts by weight, the resulting composition will not have sufficient impact resistance, and if it exceeds 40 parts by weight, the mechanical strength of the resulting composition will decrease, which is preferable. do not have. Furthermore, the maleimide-based graft copolymer of the present invention
The proportion of maleic anhydride in the monomer mixture constituting (A) is particularly important, 5 to 50% by weight, especially 10 to 50% by weight.
A range of 45% by weight is preferred. Maleic anhydride is 5
If the amount is less than 50% by weight, the heat distortion temperature of the maleimide-based graft copolymer obtained by imidization and thus the composition of the present invention will be extremely low; if it exceeds 50% by weight,
This is not preferable because the melting temperature becomes too high and moldability is significantly impaired. The aromatic vinyl monomers used in the maleimide graft copolymer (A), graft copolymer (B), and vinyl copolymer (C) include styrene, α-
These include styrene monomers such as methylstyrene, vinyltoluene, P-methylstyrene, P-t-butylstyrene, and chlorostyrene, and substituted monomers thereof, and among these, styrene and α-methylstyrene are particularly preferred. Other vinyl monomers that can be copolymerized with this include vinyl cyanide monomers such as acrylonitrile, methacrylonitrile, and α-chloroacrylonitrile, methyl acrylate, and methyl methacrylate. Among them, acrylonitrile and methyl methacrylate are particularly preferably used. The vinyl cyanide monomer constituting the graft copolymer (B) of the present invention includes acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, and the like, with acrylonitrile being preferred. Maleimide graft copolymer (A) is a monomer mixture consisting of an aromatic vinyl monomer, maleic anhydride, and other vinyl monomers copolymerizable with these in the presence of a rubbery polymer. It can be obtained by polymerizing either in solution, hydrocarbon solution or bulk melt, and then reacting with ammonia or a primary amine to convert maleic anhydride units into maleimide units, especially in an organic solvent. ammonia or primary at a temperature of 0 to 75 °C
A preferred method is to react with a class amine, remove the organic solvent, and then perform dehydration and ring closure by heating at a temperature of 150°C or higher. Specific examples of primary amines used here include methylamine, ethylamine, n-
Examples include propylamine, iso-propylamine, butylamine, aniline, tolylamine, naphthylamine and halogen-substituted aniline. In addition, the graft copolymer (B) can be produced by ordinary emulsion polymerization, and the vinyl copolymer (C) can be produced by ordinary suspension polymerization.
It can be produced by emulsion polymerization, bulk polymerization, solution polymerization, etc. The resin composition of the present invention is obtained by blending the maleimide-based graft copolymer (A), the graft copolymer (B), and the vinyl-based copolymer (C). (A) is 10 to 60 parts by weight, especially 15 to 55 parts by weight, and (B) is 5 to 30 parts by weight, especially 10 to 60 parts by weight.
25 parts by weight and (C) from 10 to 85 parts by weight, particularly from 15 to 80 parts by weight (total 100 parts by weight).
If the blending amount of the maleimide graft copolymer (A) is less than 10 parts by weight, only a composition with an extremely low heat distortion temperature will be obtained; if it exceeds 60 parts by weight, mechanical strength such as tensile strength This is not preferable because it causes a significant decrease in Furthermore, if the amount of graft copolymer (B) is less than 5 parts by weight, the impact strength will not be sufficient.
If the amount exceeds 1 part by weight, mechanical strength represented by tensile strength decreases, which is not preferable. Moreover, various properties can be exhibited by further blending other polymers with the thermoplastic resin composition of the present invention. Examples of such polymers include polyamide polymers such as nylon, polyester polymers such as polyethylene terephthalate and polybutylene terephthalate, polycarbonates, and polyacetals. There are no particular restrictions on the method of blending the maleimide-based graft copolymer (A), graft copolymer (B), and vinyl-based copolymer (C). Instead, a method is adopted in which they are supplied to an extruder at a desired ratio and melt-mixed. In addition, the thermoplastic resin composition of the present invention may be added with ordinary hindered phenolic antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants to further improve thermal stability, or may be added with lubricants. It is also possible to further improve fluidity. Depending on the purpose, fiber reinforcing agents such as glass fiber and carbon fiber,
Inorganic fillers, colorants, pigments, conductive materials, etc. can also be blended. Furthermore, flame retardation can be achieved by mixing general halogenated organic compound flame retardants such as tetrabromobisphenol A, decabromobiphenyl ether, brominated polycarbonate, etc. with antimony trioxide into the resin composition of the present invention. It is. As explained above, the thermoplastic resin composition of the present invention has an excellent balance of heat resistance, typified by heat distortion temperature, and mechanical properties, typified by impact strength, and can be used in a variety of applications that take advantage of these properties. It is expected to be applied to The present invention will be further explained below using reference examples and examples. In the Reference Examples and Examples, the heat distortion temperature was measured in accordance with ASTM D-648-56, the Izot impact strength was measured in accordance with ASTM D-256-56Method A, and the tensile strength at break was measured in accordance with ASTM 638-61T.
In addition, the number of parts means parts by weight, and the number of parts means percent by weight. Reference Example 1 [Preparation of maleimide-based graft copolymer (A-1)] In a polymerization tank equipped with a stirrer and a reflux condenser, 25 parts of polybutadiene rubber "Diene NF-55A" (manufactured by Asahi Kasei Corporation) and 59.6 parts of styrene were added. After purging the system with nitrogen gas, it was stirred at room temperature all day and night.
Rubber was dissolved in styrene. To this, 71.4 parts of methyl ethyl ketone and 0.3 parts of benzoyl peroxide (initiator) were charged and dissolved. Separately, a solution was prepared by dissolving 40.4 parts of maleic anhydride in 45.2 parts of methyl ethyl ketone. After the temperature inside the tank was set to 80°C, a maleic anhydride-methyl ethyl ketone solution was supplied to the polymerization tank at a rate of 21.4 parts/hr for 4 hours. After the supply was completed, the mixture was kept at 80° C. for another 2 hours, and then cooled to obtain a milky white viscous liquid. The reaction solution was sampled, and unreacted monomers were quantified by gas chromatography. No maleic anhydride was detected, and the polymerization rate was 94%.
After the reaction, 25.4 parts of aniline and 25.4 parts of methyl ethyl ketone were added, and the mixture was allowed to react at room temperature for 30 minutes. This reaction solution was added to toluene, and the solid content was dried separately. This was kneaded for 15 minutes at 250°C using a Brabender to perform imide ring closure, resulting in 18% rubber and N-
A maleimide-based graft copolymer (A-1) containing 48% phenylmaleimide was prepared. Reference Example 2 [Preparation of maleimide-based graft copolymer (A-2)] In the same polymerization tank as in Reference Example 1, 20 parts of polybutadiene rubber "Diene NF-55A" (manufactured by Asahi Kasei Corporation) and 50.6 parts of styrene were charged. After purging the system with nitrogen gas, the mixture was stirred at room temperature all day and night to dissolve the rubber in styrene. To this, 71.4 parts of methyl ethyl ketone and 0.3 parts of benzoyl peroxide (initiator) were charged and dissolved. Meanwhile separately, maleic anhydride 47.6
A solution was prepared by dissolving 53.3 parts of methyl ethyl ketone. After the temperature inside the tank was set to 80°C, a maleic anhydride-methyl ethyl ketone solution was supplied to the polymerization tank at a rate of 25.2 parts/hr for 4 hours. After the supply was completed, the mixture was kept at 80° C. for another 2 hours, and then cooled to obtain a milky white viscous liquid. When the reaction solution was sampled and the unreacted monomer was quantified by gas chromatography, maleic anhydride was not detected and the polymerization rate was low.
It was 95%. After the reaction, 25.4 parts of aniline and 28.6 parts of methyl ethyl ketone were added and reacted at room temperature for 30 minutes. This reaction solution was added to toluene, and the solid content was dried separately. This was kneaded using a bran bender at 270°C for 15 minutes to perform imide ring closure.
A maleimide-based graft copolymer (A-2) containing 13% rubber and 56% N-phenylmaleimide was prepared. Example 1 Maleimide-based graft copolymers A-1 and A-2 prepared in Reference Examples 1 and 2, styrene-butadiene-acrylonitrile graft copolymer (ABS) with a rubber content of 60%, and styrene-acrylonitrile copolymer (acrylonitrile After melt-extruding 28%) (SAN) using an extruder according to the blending ratio in Table 1,
The physical properties of the test pieces obtained by injection molding were measured.
The measurement results of heat distortion temperature, Izot impact strength and tensile strength at break are shown in Table 1 along with the blending ratio.

[Table] As is clear from Table 1, composition No. of the present invention.
Nos. 1 to 3 are excellent in thermal distortion temperature, Izot impact strength, and tensile breaking strength in a well-balanced manner, whereas maleimide-based graft copolymer (A), graft copolymer (B), or copolymer (C) ) (Nos. 4 and 5), and cases where the blending ratio of the present invention is not met (Nos. 4 and 5).
7) In the case of a composition of graft copolymer (B) and copolymer (C) (No. 6) and in the case of a composition of a maleimide-containing copolymer and graft copolymer (B) (No. .
In case 8), only a composition can be obtained which is inferior in any one of heat distortion temperature, Izod impact strength and tensile strength at break.

Claims (1)

[Scope of Claims] 1 (A) 50 to 80% by weight of an aromatic vinyl monomer, 5 to 50% by weight of maleic anhydride, and copolymerizable with these in the presence of 5 to 40 parts by weight of a rubbery polymer. A maleimide-based graft copolymer obtained by graft polymerizing 60-95 parts by weight of a monomer mixture consisting of 0-30% by weight of a vinyl monomer with ammonia or a primary amine. (B) Grafting 80-20% by weight of a monomer mixture consisting of an aromatic vinyl monomer and a vinyl cyanide monomer in the presence of 20-80% by weight of a rubbery polymer. 5 to 30 parts by weight of a graft copolymer obtained by polymerization and (C) 10 to 85 parts by weight of a vinyl polymer obtained by polymerizing an aromatic vinyl monomer or another vinyl monomer copolymerizable therewith. A thermoplastic resin composition containing (A), (B) and (C) in a total of 100 parts by weight.