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:
Feb. 27, 2007
Filed:
Nov. 29, 2004
Takeshi Hirokane, Kanagawa, JP;
Shojiro Kuwahara, Kanagawa, JP;
Tsuyoshi Ikeda, Kanagawa, JP;
Nobuya Saegusa, Kanagawa, JP;
Tomohito Oyama, Kanagawa, JP;
Takeshi Hirokane, Kanagawa, JP;
Shojiro Kuwahara, Kanagawa, JP;
Tsuyoshi Ikeda, Kanagawa, JP;
Nobuya Saegusa, Kanagawa, JP;
Tomohito Oyama, Kanagawa, JP;
Mitsubishi Gas Chemical Company, Inc., Tokyo, JP;
Abstract
In the invention, a polyester resin comprising dicarboxylic acid constitutional units and diol constitutional units wherein 5 to 60 mol % of the diol constitutional units has a cyclic acetal skeleton is produced by a process comprising an oligomerization step and a polymerization step. In the oligomerization step, an ester having a limited acid value is transesterified with a diol having a cyclic acetal skeleton in the presence of a basic compound to obtain an oligomer. The oligomer is then polymerized in the subsequent polymerization step to increase the molecular weight.