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. 03, 1998
Filed:
Jul. 16, 1996
Chung Yup Kim, Seoul, KR;
Hyun Nam Cho, Seoul, KR;
Hoi Wan Yoo, Seoul, KR;
Hyung Joon Kim, Kyungki-Do, KR;
Korea Institute of Science and Technology, Seoul, KR;
Abstract
A method for preparing polyester by use of a catalyst. The method comprises the steps of: esterifying either a terephthalic acid, a dicarboxylic acid containing terephthalic acid or derivatives thereof with either ethylene glycol or a glycol containing ethylene glycol, or derivatives thereof to produce an esterification product containing either bis(.beta.-hydroxyethyl) terephthalate, its low molecular weight polymer, or a combination of .beta.-hydroxyethyl terephthalate and its low molecular weight polymer; and continuously polycondensing the obtained esterification product to prepare a polyester, wherein in the said polycondensing step, a composite polymerization catalyst dissolved in an ethylene glycol or an ethylene glycol-containing solution, consisting of a compound of antimony, a compound of titanium, and a compound of tin is used. The method can considerably reduce both the esterification time and the polycondensation time and provides a good color, reduced content of diethylene glycol and reduced concentration of terminal carboxyl groups in the prepared polyesters.