Nippon Shokubai Co., Ltd.

Nippon Shokubai

Fumioki Shimoyama

Yuichi Kita

Kazuo Kishino

Kazumi Fujioka

Kinichi Nakayama

Minoru Yamaguchi

Osamu Koso

Kimio Uda

An acrylonitrile solution of maleimide manifesting transparency, precluding coloration and opacification during the course of handling, and excelling in stability, a method for the preparation of the acrylonitrile solution, and an acrylonitrile based copolymer obtained by using the acrylonitrile solution are provided. The acrylonitrile solution of maleimide is such that, when it is subjected to a forced coloration test, the differences &Dgr;L, &Dgr;a, &Dgr;b values (invariably as absolute values) each between L, a, and b values before and after the test are respectively not more than 5, not more than 5, and not more than 10. The acrylonitrile solution of maleimide is prepared by lowering the water content in the acrylonitrile solution to a level of not more than 0.1% by weight, or causing the acrylonitrile solution to permit coexistence therein of a polymerization inhibitor and lowering the water content in the acrylonitrile solution to a level of not more than 0.3% by weight.

Acrylonitrile solutions of maleimides, method for preparation thereof, and acrylonitrile based copolymers obtained by use of the solutions

Thermoplastic copolymer and process for the production thereof

An acrylonitrile solution of maleimide manifesting transparency, precluding coloration and opacification during the course of handling, and excelling in stability, a method for the preparation of the acrylonitrile solution, and an acrylonitrile based copolymer obtained by using the acrylonitrile solution are provided. The acrylonitrile solution of maleimide is such that, when it is subjected to a forced coloration test, the differences .DELTA.L, .DELTA.a, and .DELTA.b values (invariably as absolute values) each between L, a, and b values before and after the test are respectively not more than 5, not more than 5, and not more than 10. The acrylonitrile solution of maleimide is prepared by lowering the water content in the acrylonitrile solution to a level of not more than 0.1% by weight, or causing the acrylonitrile solution to permit coexistence therein of at least one member selected from the group consisting of alkyl-substituted hydroxybenzenes and hindered phenols and at least one member selected from the group consisting of phosphorous esters, phosphoric esters, phosphine, and phosphoric acid amides, or lowering the water content in the acrylonitrile solution to a level of not more than 0.3% by weight and causing the acrylonitrile solution to permit coexistence therein of at least one member selected from the group consisting of alkyl-substituted hydroxybenzenes, hindered phenols, phosphorous esters, phosphoric esters, phosphine, and phosphoric acid amides.

Acrylonitrile solutions of maleimides, method for preparation thereof,

This invention provides a maleimide-based copolymer in which, because its molecular weight-retention ratio at high temperature is high, deterioration of physical properties by heating is little. Also, this invention provides a process wherein a maleimide-based copolymer is arranged so as not to heat more than necessity and thereby a maleimide-based copolymer containing only a small amount of residual volatile components is efficiently obtained without deterioration of physical properties. The maleimide-based copolymer is such as having a glass transition temperature of 170.degree. C. or higher, a weight-average molecular weight of 100,000 to 500,000, and a molecular weight-retention ratio of 90% or more when heated at 280.degree. C. for 10 minutes. When this copolymer is produced, volatile components are separated by supplying a polymer composition containing said copolymer and volatile components to a vent type screw extruder and operating this extruder under condition of a screw rotation number of 50 to 150 rpm.

Maleimide-based copolymer and process for producing it

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Hyogo, Japan

Fumioki Shimoyama