Process for the preparation of carbonic acid esters of polyester-polyols

US4191705A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Christian Lindner · Bensheim, DE
• Carlhans Suling · Odenthal, DE
• Herbert Bartl · Odenthal, DE
• Manfred Schreckenberg · Krefeld, DE
• Dieter Freitag · Krefeld, DE
• Klaus Konig · Leverkusen, DE

Key dates

• Filing date: Oct 25, 1977
• Grant date: Mar 4, 1980
• Expiry date: Oct 25, 1997

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G63/916
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

The present invention relates to a process for the preparation of carbonic acid esters of polyester-polyols by transesterifying the polyols with carbonic acid aryl esters at elevated temperatures under vacuum in the presence of a catalyst. The reaction conditions are controlled to avoid the formation of by-products and the chain extension of the polyester-polyols. The present invention is also concerned with the polyester carbonic acid esters so formed, their use in producing polycarbonate block copolymers and the copolymers so produced. The copolymers may be produced by transesterifying the polyester carbonic acid esters with bisphenols and subjecting the bis-hydroxyaryl carbonates so formed to normal polycarbonate synthesis such as interfacial or melt polycondensation.