Mitsubishi Rayon Company, Limited

Atsushi Kimura

Yutaka Toyooka

Kazuo Kishida

Yasunori Tsuneshige

Katsutoshi Kajimura

A maleimide copolymer which consists essentially of greater than 28% by weight and less than or equal to 65% by weight of a maleimide monomer unit, greater than or equal to 16% by weight and less than 72% by weight of at least one monomer unit selected from the group consisting of aromatic vinyl compound monomer units and methacrylate monomer units, and 0-25% by weight of another vinyl compound monomer unit and which contains 0.1% by weight or less of the residual maleimide monomer and 0.5% by weight or less of volatile components other than the maleimide monomer and which has a ratio (Mw/Mn) of a weight average molecular weight Mw to a number average molecular weight Mn of 3 or less, a yellowness index of 30 or less and an intrinsic viscosity of from 0.3 to 1.5. The maleimide copolymer of the present invention is excellent in heat resistance, transparency, chemical resistance, impact resistance, moldability and the like.

Maleimide copolymer and a process for producing the same

A heat resistant and impact resistant resin composition is disclosed which composition comprises 5 to 95 parts by weight of a maleimide copolymer (A) prepared by continuous polymerization in the absence of water, containing only small amounts of residual monomers and volatile components, and having a Mw/Mn of not greater than 3, a yellow index of not greater than 30, and an intrinsic viscosity of 0.3 to 1.5, and 5 to 95 parts by weight of a rubber-reinforced resin (B).

Heat resistant and impact resistant resin composition

The present invention provides a process for the preparation of maleimide copolymers by emulsion polymerization of an aromatic vinyl monomer, a vinyl cyanide monomer and a maleimide monomer in specific proportions wherein the polymerization is carried out by charging not less than a specific proportion of the aromatic vinyl monomer and optionally not more than a specific proportion of the vinyl cyanide monomer into the polymerization system before initiation of the polymerization; adding, continuously or dividedly, a mixture composed of the total amount of the maleimide monomer and the remainder of the other monomers to the polymerization system after initiation of the polymerization; maintaining the pH of the aqueous phase of the polymerization system in the range of 3 to 9 at the initiation of said polymerization; and using a redox catalyst containing an oil-soluble organic peroxide. According to this polymerization process, maleimide copolymers having excellent thermal resistance and resistance to thermal decomposition can be prepared in high yield. The present invention also provides a resin composition having excellent thermal resistance, resistance to thermal decomposition, and impact resistance which is formed by blending, in a specific proportion, a maleimide copolymer prepared by the aforesaid process with a rubber-reinforced resin obtained by grafting a vinyl cyanide monomer or the like onto a specific elastomer; and optionally blending the resulting thermoplastic resin composition with a thermoplastic resin that is hard at room temperature.

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Ohtake, Japan

Atsushi Kimura