Preparation of insoluble polymer powders which are only slightly swellable

US4647637A · kind A · utility

Assignee

• BASF SE

Inventors

• Chung-Ji Tschang · Bad Dürkheim, DE
• Karlheinz Messmer · Bad Dürkheim, DE
• Walter Denzinger · Speyer, DE

Key dates

• Filing date: Sep 18, 1985
• Grant date: Mar 3, 1987
• Expiry date: Sep 18, 2005

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08F226/10
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

Insoluble polymer powders which are only slightly swellable and are based on N-vinylpyrrolidone are prepared by polymerization of N-vinylpyrrolidone or a mixture of this with copolymerizable monomers and from 0.1 to 10% by weight, based on the total amount of monomers, of a crosslinking agent in a powder bed in the presence of a heat-transfer medium, which is inert to the reactants, and in the absence of oxygen and polymerization initiators, at from 90.degree. to 220.degree. C., while maintaining the powder state, circulating the reaction mass and evaporating the heat-transfer medium from the polymerization zone. The resulting insoluble polymers which are only slightly swellable are used as adsorbents or formulation assistants for fertilizers and crop protection agents.