JPH0312100B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a thermoplastic resin composition that has excellent heat resistance, impact resistance, and thermal stability during processing, and more specifically, the present invention relates to a thermoplastic resin composition that is mainly composed of α-methylstyrene monomer and vinyl cyanide monomer. , relates to a thermoplastic resin composition formed by blending a copolymer having 2 mol % or less of vinyl cyanide chains and polycarbonate. Traditionally, in place of metal parts, molding has been made using acrylonitrile and styrene copolymer resin or ABS resin mixed with rubber and polycarbonate because of its excellent lightness, moldability, impact resistance, heat resistance, etc. It has been proposed to be used as a resin for
No., Japanese Patent Publication No. 111150/1973). However, all of these conventional resin compositions have poor thermal stability during processing, poor color tone, and a significant decline in physical properties, so in order to avoid these drawbacks, it is necessary to increase the amount of polycarbonate blended. It was hot. However, those containing a large amount of polycarbonate have the disadvantage that moldability is reduced due to the high melt viscosity of polycarbonate. As a result of extensive research aimed at improving these drawbacks without increasing the amount of polycarbonate blended, the present inventors have discovered a copolymer containing α-methylstyrene monomer and vinyl cyanide monomer as main components. In polymers, vinyl cyanide chains are susceptible to denaturation and decomposition at high processing temperatures, which induces molecular scission in polycarbonate, resulting in deterioration in color tone and physical properties of the molded resin. It was discovered that the copolymer is stabilized when the vinyl cyanide does not form chains but forms an alternating copolymer, and it is particularly desirable that the vinyl cyanide chains account for 2 mol% or less. This is the heading that led to the completion of the present invention. That is, the object of the present invention is to provide (A) a vinyl cyanide chain obtained by copolymerizing an α-methylstyrene monomer, a vinyl cyanide monomer, and a mixture of a vinyl monomer copolymerizable with these. 40 to 90 parts by weight of a copolymer that is 2 mol% or less, (B) a butadiene polymer or butadiene copolymer, or an acrylic ester polymer or an acrylic ester copolymer, an aromatic vinyl monomer and cyanide. 0 to 30 parts by weight of a graft copolymer obtained by graft polymerizing a mixture with a vinyl monomer or an aromatic vinyl monomer, a vinyl cyanide monomer, and a vinyl monomer copolymerizable with these. , and (C) polycarbonate
This is achieved by providing a thermoplastic resin composition containing 60 to 10 parts by weight. In the present invention, the α-methylstyrene monomer as component (A) may partially have nuclear substitution such as halogen. Furthermore, examples of vinyl cyanide monomers include acrylonitrile and methacrylonitrile. Vinyl monomers that can be copolymerized with these include styrene, methyl methacrylate, ethyl methacrylate, halogen-substituted styrene, and alkyl-substituted styrene. These composition ratios are usually 73 to 83% by weight of α-methylstyrene monomer and 17 to 27% by weight of vinyl cyanide monomer. A large amount of vinyl cyanide monomer is not preferred because the number of vinyl cyanide chains increases. When the amount of vinyl cyanide monomer is extremely small, it is extremely difficult to polymerize α-methylstyrene monomer, making it difficult to form a copolymer. Vinyl monomers copolymerizable with these may be contained in the copolymer in an amount of 10% by weight or less. The vinyl cyanide chain in the copolymer of component (A) is 2
It is less than mol %, preferably less than 1 mol %. Such copolymers are made of vinyl cyanide monomers and
A method of copolymerizing a complex with ZnCl ₂ etc. and an α-alkyl aromatic vinyl monomer (Journal of Polymer
Science: Polymer Chemistry Edition,
Vol.12, 1965-1701, (1974); hereinafter referred to as JOPS. ), or a method of copolymerizing a vinyl cyanide monomer and an α-methylstyrene monomer while keeping the content of vinyl cyanide monomer at a ratio below an azeotrope (preferably, before the copolymerization is completed). It can be produced by a method such as stopping the copolymerization. In addition, the degree of vinyl cyanide chain is
Obtain the ¹³ C NMR absorption spectrum of the copolymer of component (A) according to the method described in JOPS,
The chemical shift is the ratio of the area enclosed by the absorption line of the absorption spectrum of the cyano group existing at 118 to 122 ppm to the area enclosed by the absorption line of the absorption spectrum of the cyano group existing at 118 to 125 ppm (absorption Calculate the peak area ratio) and calculate this absorption peak area ratio as
Calculated in mol% by multiplying by the molar fraction of vinyl cyanide in the copolymer (A). Next, examples of monomers that can be copolymerized with butadiene in the butadiene copolymer of component (B) include styrene and methyl methacrylate. Further, the ester moiety of the acrylic ester is preferably an aliphatic alkyl group such as methyl, ethyl, and butyl. Monomers that can be copolymerized with the acrylic ester of the acrylic ester copolymer include ethylene, vinyl acetate, and methyl methacrylate. In addition, aromatic vinyl monomers include styrene, halogen-substituted styrene, alkyl-substituted styrene, α
- Examples include methylstyrene. Examples of vinyl cyanide monomers include acrylonitrile and methacrylonitrile. Examples of vinyl monomers copolymerizable with aromatic vinyl monomers and vinyl cyanide monomers include styrene, methyl methacrylate, ethyl methacrylate, and halogen-substituted styrene. The blending ratio of the butadiene polymer or butadiene copolymer, or the acrylic ester polymer or acrylic ester copolymer and the mixture to be grafted is 20 to 200 parts by weight, preferably 50 parts by weight, per 100 parts by weight of the former. ~100 parts by weight. Vinyl cyanide in the graft portion is also easily decomposed, so it is not preferable to increase the amount. Graft polymerization is carried out by adding a monomer mixture to be grafted to a rubber emulsion such as a butadiene (co)polymer or an acrylic acid ester (co)polymer and polymerizing the rubber emulsion according to a conventional method. Next, as the polycarbonate of component (C),
Known in the art, they are generally made by reacting dihydroxy or polyhydroxy compounds with diesters of phosgene or carbonic acid, such as by reacting bisphenols with phosgene or diaryl carbonates. Examples of bisphenols include bis(hydroxyaryl)alkanes and those having a substituent of a halogen group or an alkyl group on the phenyl group, and preferred examples include 2,2'-
Bis(4,4'-hydroxyphenyl)propane (bisphenol A). In the composition of the present invention, the copolymer of component (A) 40
~90 parts by weight of component (C) polycarbonate
60 to 10 parts by weight, preferably 50 to 20 parts by weight. If more than 60 parts by weight of polycarbonate is blended, moldability will decrease. If it is less than 10 parts by weight, the impact resistance imparted to the molded resin is insufficient. Component (B), a graft copolymer, is blended to further improve impact resistance, but if it is blended in an amount exceeding 30% by weight, heat resistance decreases, which is not preferable. The composition of the present invention is prepared by mixing components (A), (B), and (C) in a suitable mixing device, such as an extruder,
Mixing using a kneader, ball mill, roll mill, Banbury mixer, etc., or by creating a solution or dispersion of each copolymer and mixing the solutions together, the dispersions together, or the solutions and dispersions to co-coagulate. However, the method of blending is not particularly limited. When mixing the ingredients, fillers, stabilizers, flow improvers, demolding agents, antistatic agents, and other additives can be added. As detailed above, the composition of the present invention has particularly good thermal stability during molding, and the molded product has excellent heat resistance and impact resistance, so it can be used for various purposes such as parts for automobiles and electrical appliances. Useful for the application. The present invention will be explained in more detail with reference to Examples below. In addition, parts and percentages described in the examples are based on weight unless otherwise specified. Example 1 82 parts α-methylstyrene, 18 parts acrylonitrile
200 parts of water, 3 parts of sodium dodecylbenzenesulfonate, 0.3 parts of t-dodecylmercaptan as a chain transfer agent, and 0.06 parts of potassium persulfate as a polymerization catalyst.
Place the sample in a stainless steel autoclave and heat at 70℃.
Polymerization was carried out for 3 hours. The polymerization rate was 56%. A portion of the polymer latex was taken and heated to remove volatile components, then dissolved in acetone and reprecipitated with methanol to obtain a purified copolymer, which was subjected to carbon 13 NMR measurement. For polymer latexes, calcium chloride
3PHR was added, and dehydration, washing, and drying were performed by conventional methods. 60 parts of this copolymer powder and polycarbonate (Teijin Kasei Co., Ltd. trade name, Panlite L1250)
40 parts were mixed, granulated using an extruder, and a test piece was produced using an injection molding machine. The results are shown in the table. Comparative Example 1 In Example 1, 70 parts of α-methylstyrene,
Polymerization rate by polymerizing 30 parts of acrylonitrile for 20 hours
Example 1 was carried out in exactly the same manner as in Example 1, except that a 99.5% copolymer was obtained and used. Example 2 Polybutadiene latex (Japan Synthetic Rubber Co., Ltd. trade name, JSR-0700) 50 parts (solid content), ferrous sulfate
0.005 part, disodium ethylenediaminetetraacetate
0.01 part of sodium formaldehyde sulfoxylate, and water were charged into a stainless steel autoclave, making the total amount of water 220 parts. Maintaining the temperature at 60℃, add 40 parts of styrene, 10 parts of acrylonitrile, and cumene hydroperoxide under stirring.
A mixture consisting of 0.25 parts was added dropwise over 8 hours, and an additional 1
Stirring was continued for an hour to complete the polymerization. The obtained graft copolymer latex and the α-methylstyrene-acrylonitrile copolymer latex obtained in Example 1 were mixed so that the blending ratio of polybutadiene was 7% in terms of solid content, and 1.0% hindered phenol was added to the mixture. A resin powder was obtained by adding PHR and performing the same operation as in Example 1. This resin powder 70
and 30 parts of polycarbonate were mixed and granulated. Comparative Example 2 The same procedure as Example 2 was carried out except that the copolymer of Comparative Example 1 was used in place of the α-methylstyrene-acrylonitrile copolymer of Example 2. Example 3 Instead of the α-methylstyrene-acrylonitrile copolymer of Example 1, α-methylstyrene 82
Example 1 was carried out in the same manner as in Example 1, except that a copolymer obtained by polymerizing 13 parts of acrylonitrile, 13 parts of acrylonitrile, and 5 parts of methyl methacrylate by the method of Example 1 was used.

[Table] Example 4 In addition to the composition of Example 1, 20 parts of Vitax 6100 (manufactured by Hitachi Chemical), which is commercially available as an AAS resin (a resin obtained by graft polymerizing acrylonitrile and styrene to n-butyl acrylate rubber), was added. The mixture was mixed and granulated. (α-methylstyrene-acrylonitrile copolymer: polycarbonate:
AAS resin = 50:33:17). When this was molded at 290°C, the molded piece was yellow, almost white. The impact strength of Izotsu is 25Kg・cm/cm using a 1/4 inch test piece.
It was hot. Example 5 The blending ratio in Example 1 was changed, and 80 parts of α-methylstyrene-acrylonitrile copolymer and 20 parts of polycarbonate were mixed and molded at 290°C.
The molded piece was yellow, almost white. The impact strength of IZOT was 15 kg cm/cm using a 1/8 inch test piece.

Claims (1)

[Claims] 1 (A) A copolymerized mixture of α-methylstyrene monomer, vinyl cyanide monomer, and a vinyl monomer copolymerizable with these, and the vinyl cyanide chain is 2 mol% or less 40 to 90 parts by weight of copolymer, (B) butadiene polymer or butadiene copolymer, or acrylic ester polymer or acrylic ester copolymer, and aromatic vinyl monomer and vinyl cyanide monomer. 0 to 30 parts by weight of a graft copolymer obtained by graft polymerization of a mixture of or a mixture of an aromatic vinyl monomer, a vinyl cyanide monomer, and a vinyl monomer copolymerizable with these, and (C) polycarbonate A thermoplastic resin composition containing 60 to 10 parts by weight.