Absorbent polymers, manufacturing process and their use in particular for sanitary articles

US5258448A · kind A · utility

Assignee

• Societe Francaise Hoechst · FR

Inventors

• Paul Mallo · Croissy-sur-Seine, FR
• Fritz Engelhardt · Frankfurt am Main, DE
• Ulrich Riegel · Landstuhl, DE
• Rüdiger Funk · Niedernhausen, DE

Key dates

• Filing date: Oct 6, 1992
• Grant date: Nov 2, 1993
• Expiry date: Oct 6, 2012

Classification

• Technology area (CPC A): Human Necessities
• CPC primary: A61L15/60
• WIPO field: Medical technology
• WIPO sector: Instruments

Abstract

Hydrophobic, cross-linked absorbent polymers, insoluble in water, in the form of microbeads , based on silica and acrylic acid partially salified by an alkali metal, are obtained by a polymerization process in a water-in-oil suspension in which an aqueous phase obtained extemporaneously from (1), an aqueous solution containing one or more hydrosoluble polymerization initiators, which are free radical generators, and (2), an aqueous phase containing at a concentration of 50.+-.15% by weight a mixture of by weight 2 to 25% of colloidal silica and 98 to 75% of acrylic acid of which 60 to 80 is salified by an alkaline metal, is introduced slowly, under agitation, into a totally deoxygenated oil phase maintained at boiling point and containing a protective colloid, with an aqueous phase to oil phase weight ratio of between 0.8 and 1.2, then when the polymerization reaction is finished, 15 to 55% of the water present is eliminated by azeotropic distillation with recycling of the organic solvent, then 0.01 to 0.06% in molar proportions relative to the monomers of ethyleneglycol diglycidyl ether is introduced into the reaction mixture at boiling point and azeotropic distillation of the res…