JPH0158216B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a thermoplastic resin composition with improved heat resistance and impact resistance, and more particularly to a thermoplastic resin composition obtained from a specific copolymerization ratio of an aromatic vinyl monomer and maleic anhydride. The present invention relates to a resin composition in which a rubber-reinforced styrenic polymer and a polyphenylene ether are blended into a resin in specific proportions. Conventional aromatic vinyl monomers, especially copolymers of styrene and maleic anhydride, have better heat resistance than styrenic resins, but have poor mechanical properties, especially impact resistance. Because it is brittle, its uses are extremely limited. Therefore, as a method for improving the impact resistance of such an aromatic vinyl monomer-maleic anhydride copolymer, a method of copolymerizing an aromatic vinyl monomer and maleic anhydride in the presence of rubber has been adopted. However, as a result of adding rubber, the polymerization system becomes extremely viscous, making it difficult to control the polymerization, and limiting the type and amount of rubber that should be used, making it difficult to improve impact value. Although we can expect
This has the negative effect of reducing heat resistance.
There are still difficulties in such copolymerization methods in the coexistence of rubber. Moreover, copolymerizing aromatic vinyl monomers and maleic anhydride in the coexistence of rubber in this way poses problems in terms of equipment, as there are many factors that lead to further increases in costs. We have no choice but to rely on momentum blending technology. However, it is quite difficult to combine the conflicting properties of heat resistance and impact resistance in a blend system, and so far, West German Patent No. 2524787 has disclosed that styrene-maleic anhydride copolymer and A blend system consisting of a styrene-butadiene block polymer or its hydrogenated product, an acrylic graft copolymer or a similar polymer, and, if necessary, polyphenylene ether, etc., has a high heat distortion temperature and high impact strength. However, there are some difficulties in balancing the heat distortion temperature (heat resistance) and impact resistance, and the multi-component blends described above are expensive and uneconomical. , it is hard to say that it is industrially advantageous. However, in view of this background, the present inventors
Although it is a blend system, we have conducted extensive research to improve the impact resistance of the copolymer of aromatic vinyl monomer and maleic anhydride without any loss in heat resistance. A copolymer of an aromatic vinyl monomer and maleic anhydride containing a specific proportion of maleic anhydride is blended with a specific amount of a rubber reinforcing resin, particularly a reinforcing styrenic polymer and a polyphenylene ether. As a result, the present invention was completed by discovering a thermoplastic resin composition that ensured heat resistance and impact resistance with an inexpensive blend formulation and also had physical properties superior to those of polymerized formulations. I reached it. That is, the present invention provides (A) 25 to 45.5% by weight of a thermoplastic resin obtained by copolymerizing 20% by weight or less of maleic anhydride and 80% by weight or more of an aromatic vinyl monomer; (B) cis- 25 to 60% by weight of a rubber-reinforced styrenic polymer obtained by polymerizing styrene alone or with a styrene derivative in the presence of a polybutadiene rubber having 90% by weight or more of a 1,4-structure, and (C) polyphenylene. The object of the present invention is to provide a thermoplastic resin composition comprising 3 to 25% by weight of nylene ether and having the above-mentioned components (A), (B), and (C) totaling 100% by weight. Here, the thermoplastic resin (A) is obtained by copolymerizing 20% by weight or less of maleic anhydride and 80% by weight of an aromatic vinyl monomer, preferably 8 to 15% by weight. % maleic anhydride and
It is obtained from 85 to 92% by weight of aromatic vinyl monomer. The preferred polymerization method in this case is solution polymerization or bulk polymerization, for example, a polymerization method in which maleic anhydride is added at a rate substantially slower than the polymerization rate of styrene monomer. The most typical such aromatic vinyl monomer is styrene, but it also includes styrene derivatives such as α-methylstyrene, o-, m- or p-methylstyrene, dimethylstyrene or chlorstyrene. However, some of these aromatic monomers may also be replaced by other copolymerizable monomers such as methyl methacrylate, methyl acrylate, ethyl methacrylate, acrylonitrile, methacrylonitrile or halogen-containing vinyl monomers. Of course. On the other hand, in the present invention, the term "maleic anhydride" is not limited to this, but also includes derivatives of maleic anhydride such as chloromaleic anhydride or dichloromaleic anhydride. The amount of the thermoplastic resin (A) to be used is within the range of 25 to 48.5% by weight based on the composition of the present invention, and the total amount with the other two components (B) and (C) is
This amount also satisfies the condition of 100% by weight. Next, the above-mentioned rubber-reinforced styrenic polymer is a thermoplastic polymer obtained by polymerizing styrene alone or with a styrene derivative in the presence of polybutadiene rubber having 90% by weight or more of cis-1,4-structure. This refers to resins, and those having an Izot impact strength of 8 to 20 kg-cm/cm and a Vicat softening point of 82 to 110°C are particularly preferred.
Here, as the styrene derivative, α
-methylstyrene, o-, m- or p-methylstyrene, dimethylstyrene or chlorstyrene. Here, the styrene compound refers to styrene or a derivative thereof, and vinyl compounds copolymerizable with the styrene compound include vinyl cyanide, acrylic acid, methacrylic acid, acrylic ester, methacrylic ester, or maleic anhydride. It includes things such as things. To obtain the polymer (B), a polybutadiene rubber having 90% by weight or more of cis-1,4-structure is used, and it is grafted with styrene or styrene and a styrene derivative by a method such as suspension polymerization or continuous bulk polymerization. It is preferable to polymerize, and the rubber content in the polymer (B) obtained in this way is 7 to 7.
Preferably it is within the range of 20% by weight. If the rubber content is less than 7% by weight, it is difficult to obtain a high impact value;
If the amount exceeds % by weight, the heat resistance decreases, which is not preferable. Here, the polybutadiene having 90% by weight or more of the cis-1,4-structure means a rubber obtained by polymerizing butadiene with high stereoregularity, and is a rubber obtained by polymerizing butadiene with high stereoregularity.
Refers to those with a structure and a content of 1,2-vinyl bonds of less than 10% by weight. The amount of the polymer (B) to be used is within the range of 25 to 60% by weight based on the composition of the present invention, and at the same time, the total amount with the other two components (A) and (C) is
This amount also satisfies the condition of 100% by weight. Furthermore, the polyphenylene ether (C) mentioned above has the general formula (However, R ₁ and R ₂ in the formula are an alkyl group having 1 to 4 carbon atoms or a halogen atom, and p is 50 to
300, preferably an integer between 70 and 250. ) with an intrinsic viscosity [η] of 0.5 to 0.7
(25℃, in chloroform) range is best;
Among them, the most representative ones are poly(2,6-dimethylphenylene-1,4-ether), poly(2,6-diethylphenylene-1,
4-ether), poly(2,6-dichlorophenylene-1,4-ether), poly(2,6-dibromophenylene-1,4-ether), poly(2
-methyl-6-ethyl-phenylene-1,4-ether), poly(2-chloro-6-methyl-phenylene-1,4-ether), poly(2-methyl-6-isopropyl-phenylene-1,4) -ether), poly(2,6-di-n-propylphenylene-1,4-ether), poly(2-bromo-
6-methyl-phenylene-1,4-ether),
Poly(2-chloro-6-bromo-phenylene-
1,4-ether), poly(2-chloro-6-ethyl-phenylene-1,4-ether), poly(2-methyl-6-chloro-phenylene-1,4)
-ether), poly(2-methyl-6-n-butyl-phenylene-1,4-ether) or poly(2-methyl-6-bromo-phenylene-1,4)
- ether) etc. The amount of the polyphenylene ether (C) used is within the range of 3 to 25% by weight based on the composition of the present invention, and at the same time, the amount of the other two components (A) and
This is within the range that also satisfies the condition that the total amount with (B) is 100% by weight. The composition of the present invention contains the aromatic vinyl monomer-maleic anhydride copolymer resin (A), the rubber-reinforced styrenic polymer (B), and the polyphenylene ether (C) in the specific proportions described above. It is obtained by blending, and any method such as powder blending, solution blending, pellet blending, extruder, kneader, or Banbury mixer such as FCM can be adopted as the blending method. In addition, if desired, antioxidants, anti-Teiden agents, ultraviolet absorbers, colorants, flame retardants, plasticizers, lubricants, or inorganic fillers such as glass fibers may be added to the composition of the present invention during blending. You can also do that. The thus obtained composition of the present invention can be processed into molded products, films, sheets, etc. by applying any molding method such as extrusion molding or injection molding, and can be used as electrical appliances, automobile parts, food containers, medical instruments, and office equipment. It is expected to be widely used in fields related to precision equipment, especially in fields that take advantage of its heat resistance and impact resistance. Next, the present invention will be specifically explained with reference to Examples, where all parts and percentages are based on weight unless otherwise specified. Examples 1 and 2 and Comparative Examples 1 to 3 Styrene-maleic anhydride copolymer "Dylark #232" (manufactured by Arco Polymers) consisting of 92% styrene and 8% maleic anhydride, rubber Reinforced styrene polymer [Styrene-butadiene graft copolymer containing 8% high-cis polybutadiene rubber manufactured by Dainippon Ink & Chemicals Co., Ltd.:
Weight average molecular weight Mw = approx. 220,000, number average molecular weight Mn
= Approximately 90,000, Melt flow rate 0.80g/10 minutes (200℃, 5g), Izotsu impact strength 10Kg-cm/
cm, Vikatsu softening point 95℃] and polyphenylene ether "PPO #534" [Product of Engineering Plastics Co., Ltd., [η] = 0.60 (25℃, in chloroform)] are specified in Table 1. After melt-mixing by extruder kneading at a ratio of [26 mm diameter hot-cut single-screw extruder (equipped with tip dalmage kneading device]), test pieces were formed by injection molding at 250°C and physical properties were measured. For comparison, "Dylarc #232" [Comparative Example 1], "Dylarc #250" (rubber-modified styrene-maleic anhydride copolymer resin manufactured by the same company) [Comparative Example 2], and "Dylark #232" - " acryloid
KM-611” (a Rohm and Haas product,
Emulsion graft polymerization of acrylic monomer in the presence of rubbery diene polymer) - "PPO
A similar test was also attempted for the three-component system [Comparative Example 3] of "#534". The above results are summarized in Table 1.

[Table] As is clear from Table 1, the composition of the present invention has a better balance between heat resistance and impact resistance than conventional compositions. Examples 3 to 5 and Comparative Example 4 Styrene-maleic anhydride copolymer "Dylarc #332" (product of the same company) consisting of 87% styrene and 13% maleic anhydride, rubber-reinforced styrenic polymer [large] Styrene-butadiene graft copolymer containing 10% high-cis polybutadiene rubber manufactured by Nippon Ink Chemical Industry Co., Ltd.: Mw = approx. 230,000, Mn = approx.
110,000, melt flow rate 0.45g/10min (200℃,
5Kg), Izotsu impact strength 12Kg-cm/cm, Vikatsu softening point 101℃], and "PPO#534" were thoroughly mixed in the specified proportions shown in Table 2, and then dried at 70℃ for 8 hours. I let it happen. Then granulated at a temperature of 230-250℃, 250-275
5x using 1oz injection molding machine under temperature of ℃
A test piece with a size of 1/2×4 (inch) was molded. Thereafter, a physical property test was conducted on this test piece, and the results shown in Table 2 were obtained.

[Table] Example 6 and Comparative Examples 5 and 6 Melt mixing was carried out in the same manner as in Examples 1 and 2 and Comparative Examples 1 to 3, except that the formulations shown in Table 3 were changed, and a test mold was molded by injection molding. A test piece was prepared by molding. Next, a practical heat resistance test and practical strength were measured for each of these test pieces. First, the practical heat resistance test was conducted by placing a test piece in hot water at 100°C and determining the dimensional change rate after 5 hours. Next, to determine the practical strength, a box-shaped test piece (205 x 124 x 21 mm, 2.0 mm thick) was formed using a 4 oz. This was done by measuring strength, tapping strength and falling ball impact strength. In addition, the molding conditions at the time of preparing the test pieces in each test were as follows. Heat resistance test (dimensional stability)...Dumbbell test piece (weight 5g, 1 oz molding machine used, molding temperature
C ₁ = 225℃, C ₂ = 230℃) Strength test: Box-shaped test piece (weight 84g, using a 4-ounce molding machine, molding temperature C ₁ = 170℃, C ₂ =
(250°C, C ₃ = 250°C, N = 230°C) The results of each of these tests are summarized in Table 3.

【table】

[Table] As is clear from Table 3, the composition of the present invention (three-component blend) has larger dimensions when immersed in boiling water than the rubber-modified styrene-maleic anhydride copolymer and the rhosus rubber-reinforced polystyrene. It is known that it has remarkable heat resistance from the standpoint of stability, and has an advantage in practical strength.

Claims (1)

[Claims] 1 Thermoplastic resin (A) obtained by copolymerizing 20% by weight or less of maleic anhydride and 80% by weight or more of an aromatic vinyl monomer (A) 25 to 48.5% by weight, cis-1,4-
Rubber-reinforced styrenic polymer (B) 25 to 60% by weight and polyphenylene ether (C) obtained by polymerizing styrene alone or with a styrene derivative in the presence of polybutadiene rubber having a structure of 90% by weight or more Consisting of 3 to 25% by weight, and the above
A thermoplastic resin composition with improved heat resistance and impact resistance, characterized in that the total of the three components (A), (B) and (C) is 100% by weight.