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:
Mar. 10, 1998
Filed:
Oct. 01, 1996
Polyplastics Co., Ltd., , JP;
Abstract
The present invention provides a process for preparing a thermally very stable polyacetal copolymer having very small unstable terminals even at a high polymerization yield, by the copolymerization of trioxane as the principal monomer with a comonomer copolymerizable therewith, wherein an isopolyacid or an acidic salt thereof is used as a polymerization catalyst; the catalyst can simply be deactivated in a small amount of a deactivator solution after the polymerization; and a washing step is not required. The copolymerization is effected with an isopolyacid or an acidic salt thereof used as a polymerization catalyst until the remaining monomers account for at most 10% by weight of all the fed monomers, and a solution containing a deactivator for the above catalyst is added in an amount of 0.01 to 10% by weight based on the resulting crude polymer to deactivate the catalyst, followed by subjecting the crude polymer intact to a heat-melting treatment without washing it.