Reduced solvent process for preparation of aqueous polyurethane dispersions with improved heat-and water-resistance

US5637639A · kind A · utility

Assignee

• H.B. Fuller Licensing & Financing, Inc · US

Inventors

• Youlu Duan · Maplewood, US
• Sonja Stammler · North Branch, US

Key dates

• Filing date: Sep 15, 1995
• Grant date: Jun 10, 1997
• Expiry date: Sep 15, 2015

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S528/905
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A process for preparing poly(urethane/urea) prepolymers and aqueous poly(urethane/urea) dispersions (PUDs) therefrom, the poly(urethane/urea) polymers having high heat resistance and good water resistance. The method employs a water soluble volatile organic solvent, such as acetone, at a level of 0.1-5%, based on final dispersion weight, a level which does not require removal for purposes of flash point considerations. The method includes the steps of reacting in the presence of a water soluble volatile organic solvent at a level corresponding to no more than 5% by weight of the final dispersion, a polyisocyanate component comprising a diisocyanate, with a polyol component to produce an isocyanate terminated polyurethane prepolymer the polyol component providing both carboxylate groups and sulfonate groups; dispersing the isocyanate terminated prepolymer in aqueous media; reacting said dispersed isocyanate terminated polyurethane prepolymer with at least one amine functional chain extender or chain terminator compound to thereby form said poly(urethane/urea) polymer; neutralizing the carboxylate and sulfonate groups of said isocyanate terminated prepolymer with an alkali hydroxide …