Encapsulated salts of sparing solubility in water, their preparation and their use

US4608277A · kind A · utility

Assignee

• Casella Aktiengesellschaft · DE

Inventors

• Ulrich Greiner · Schöneck, DE
• Karl-Heinz Keil · Hanau, DE
• Rudolf Heinrich · Emmerting, DE
• Konrad Albrecht · Kelkheim, DE

Key dates

• Filing date: Aug 2, 1985
• Grant date: Aug 26, 1986
• Expiry date: Aug 2, 2005

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/2998
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

Encapsulated salts of organic or inorganic acid particles having sparing solubility in water wherein the salt particles are surrounded by a pressure-resistant, elastic, abrasion-resistant polyurethane/polyurea casing, the ratio by weight of salt to the polyurethane component of the casing material being 1:0.2 to 1:2.5, are produced by emulsifying a mixture of 83 to 28% by weight of the salt to be encapsulated and 17 to 72% by weight of a polyurethane prepolymer containing free isocyanate groups in water in the presence of a protective colloid and reacting the emulsified prepolymer with the equivalent amount of polyamine at temperatures from 0.degree. to 80.degree. C., with vigorous mixing.