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:
Dec. 01, 1998
Filed:
Jan. 27, 1997
Kaoru Yamamoto, Shizuoka, JP;
Hiroyuki Kanai, Shizuoka, JP;
Polyplastics Co., Ltd., , JP;
Abstract
To prepare a thermally very stable polyacetal copolymer containing a very small amount of unstable parts in a high yield according to a simple process wherein an isopolyacid or an acid salt thereof is used as the polymerization catalyst in the copolymerization of trioxane as the principal monomer with a comonomer copolymerizable therewith, and wherein deactivation of the catalyst can be effected simply without fail through contact with a basic gas after polymerization without the necessity for any washing step. In the preparation of a polyacetal copolymer by the copolymerization of trioxane as the principal monomer with a cyclic ether or cyclic formal having at least one carbon--carbon bond as a comonomer, the copolymerization is effected using an isopolyacid or an acid salt thereof as the polymerization catalyst, followed by contact with a basic gas as a deactivator to deactivate the catalyst, and subsequent heat-melting treatment of the resulting crude polymer intact without washing thereof.