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:
May. 09, 2006
Filed:
Jul. 21, 2003
Takaharu Kawahara, Okayama, JP;
Toshio Tuboi, Okayama, JP;
Takaharu Kawahara, Okayama, JP;
Toshio Tuboi, Okayama, JP;
Kuraray Co., Ltd., Kurashiki, JP;
Abstract
This invention provides a method for producing a saponified ethylene-vinyl acetate copolymer in which visible imperfections (particularly fish eyes) of the saponified copolymer is inhibited. In this invention, a mixture solution is prepared by adding water to a methanol solution after saponifying an ethylene-vinyl acetate copolymer, and insoluble materials are removed from this mixture solution. Various types of filter or centrifugal separator are used to remove insoluble materials. It is preferable that the weight ratio of methanol to water is from 5:5 to 9:1, the concentration of the saponified copolymer is from 30 to 60 wt %, and the temperature is from 55 to 80° C. This method is particularly suitable for producing a saponified ethylene-vinyl acetate copolymer having an ethylene content of 20 to 70 mol % and a saponification degree of at least 95 mol %.