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:
Apr. 06, 2004
Filed:
Jul. 22, 2002
Mitsubishi Rayon Co., Ltd., Tokyo, JP;
Abstract
A process for production of methacrylic copolymers, characterized by charging a monomer mixture comprising from 70 to 95% by weight of methyl methacrylate, from 0 to 15% by weight of &agr;-methylstyrene, from 0 to 20% by weight of styrene and from 2 to 15% by weight of maleic anhydride at a molar ratio of the sum of &agr;-methylstyrene and styrene to maleic anhydride laying within the range of 1.0 to 2.5 into a polymerizing vessel containing at least one polymeric membrane layer having an oxygen permeability of 1.5×10 (mol·m ·s ·Pa ) or below, sealing the polymerizing vessel, and polymerizing the monomer mixture under heating in a gas phase; a methacrylic copolymer obtained by the production process which is reduced yellowing and shows excellent transparency and heat resistance; and an optical element composed of the methacrylic copolymer.