The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 06, 1988
Filed:
Oct. 22, 1986
Bernhard H Nowakowsky, Ludwigshafen, DE;
Juergen Beck, Mannheim, DE;
Heinrich Hartmann, Limburgerhof, DE;
Christos Vamvakaris, Kallstadt, DE;
BASF Aktiengesellschaft, Rheinland-Pfalz, DE;
Abstract
Finely divided, gel-like crosslinked polymers are prepared by a continuous method in which a monomer mixture which contains, per 100 parts by weight of acrylic acid or methacrylic acid, from 50 to 100 mol % of which in each case are neutralized, acrylamide, methacrylamide or N-vinylpyrrolidone, from 0 to 30 parts by weight of other water-soluble monoethylenically unsaturated monomers and from 0 to 20 parts by weight of water-insoluble monoethylenically unsaturated monomers is copolymerized with from 0.01 to 5 parts by weight of a crosslinking agent, in 20-65% strength by weight aqueous solution in the presence of an initiator at from 45.degree. to 95.degree. C. in a single-screw cylindrical mixer whose stirrer shaft possesses disk segments which have, at the outer end, mixing bars which are arranged in a manner such that the substances fed in at the entrance of the mixer are conveyed in the axial direction to the exit of the mixer, the aqueous monomer solution in the mixer is polymerized under from 100 to 800 mbar, and some of the water is removed during the polymerization, so that a crumb-like gel having a solids content of from 30 to 70% by weight is discharged.