Preparation of aqueous polyurethane dispersions

US5270383A · kind A · utility

Assignee

• BASF SE

Inventors

• Herbert Fisch · Monsheim, DE
• Lothar Maempel · Zeven, DE

Key dates

• Filing date: Dec 14, 1992
• Grant date: Dec 14, 1993
• Expiry date: Dec 14, 2012

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08L2666/02
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

Aqueous polyurethane dispersions are prepared by reacting (a) dihydroxy compounds having a molecular weight of from 500 to 5,000, (b) diisocyanates and, if required, (c) chain extenders having at least two hydrogen atoms which are reactive toward isocyanate groups and a molecular weight of less than 300 in the melt or in the presence of a water-miscible, inert organic solvent (S) which boils below 100.degree. C. to give a prepolymer having terminal isocyanate groups, then reacting the prepolymer with (d) salts of aliphatic aminocarboxylic or aminosulfonic acids or tertiary ammonium salts and dispersing the resulting polyurethane in water, by a process in which, before the polyurethane obtained is dispersed in water, from 5 to 60 parts by weight, based on 100 parts by weight of the polyurethane, of a polymer (p) [sic]which is dissolved in a solvent (S') boiling below 100.degree. C. is admixed, with the exception of condensates of phenol with formaldehyde and of epichlorohydrin with bisphenol A, and said polyurethane dispersions are used as adhesives or coating materials.