Process for the continuous production of polybutylene terephthalate of high molecular weight

US4499261A · kind A · utility

Assignee

• Davy McKee Aktiengesellschaft · DE

Inventors

• Helmut Heinze · Frankfurt am Main, DE
• Fritz Wilhelm · Karben, DE
• Klaus Mackensen · Frankfurt am Main, DE
• Ferdinand Finkeldei · Frankfurt am Main, DE

Key dates

• Filing date: Feb 22, 1984
• Grant date: Feb 12, 1985
• Expiry date: Feb 22, 2004

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02P20/582
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

Continuous multistep, economical, energy-saving process for making polybutylene terephthalate in which the butanediol-1,4 used to transesterify dimethyl terephthalate is supplied from the condensed vapors volatilized during the precondensation and polycondensation steps of the process. These vapors, which contain low-soluble esters of terephthalic acid as well as butanediol, are condensed by contact with fresh butanediol, and volatilized butanediol containing the esters is recycled to the initial transesterification stage for reaction with dimethyl terephthalate. No additional butanediol is required for the reaction.