Polysiloxane-polyoxyalkylene block copolymers with different polyoxyalkylene blocks in the average molecule

US5306737A · kind A · utility

Assignee

• Th. Goldschmidt. AG · DE

Inventors

• Georg Burkhart · Essen, DE
• Rolf-Dieter Langenhagen · Hattingen, DE
• Andreas Weier · Essen, DE
• Volker Zellmer · Bottrop, DE

Key dates

• Filing date: Aug 26, 1993
• Grant date: Apr 26, 1994
• Expiry date: Aug 26, 2013

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G77/46
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

Polysiloxane-polyoxyalkylene block copolymers having different polyoxyalkylene blocks in the average molecule are prepared. The mixture of the polyoxyalkylene blocks consists of at least one polyoxyalkylene group A and at least one polyoxyalkylene group B and/or at least one polyoxyalkylene group C, each polyoxyalkylene group A having an average molecular weight of 600 to 5,500 and consisting of 20 to 90% by weight of oxyethylene units and 80 to 10% by weight of oxypropylene units, polyoxyalkylene group B having an average molecular weight of 500 to 5,000 and consisting of 2 to 19% by weight of oxyethylene units and 98 to 81% by weight of oxypropylene units, polyoxyalkylene group C having an average molecular weight of 1,500 to 4,500 and consisting of oxypropylene units. Up to 20% by weight of the oxypropylene units is replaceable by oxybutylene units and the molar ratio of polyoxyalkylene groups A to the sum of the polyoxyalkylene groups B and C is 1:4 to 4:1. The block copolymers are highly effective stabilizers for the production of flexible polyurethane foams with an excellent ratio of cell fineness of the foam to air permeability of the foam.