The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 15, 1996
Filed:
Jun. 06, 1995
Nippon Shokubai Co., Ltd., Osaka, JP;
Abstract
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.