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:
Jun. 10, 1986
Filed:
Jan. 11, 1985
Robert M Blankenship, Lansdale, PA (US);
Alexander Kowalski, Plymouth Meeting, PA (US);
Rohm and Haas Company, Philadelphia, PA (US);
Abstract
Process for making core-sheath polymer particles containing voids, said particles useful for opacifying, comprising (A) emulsion polymerizing a core from a core monomer system comprised of at least one ethylenically unsaturated monomer containing acid functionality; (B) encapsulating said core with a hard sheath by emulsion polymerizing a sheath monomer system in the presence of said core, said sheath permitting penetration of fixed or permanent bases; (C) swelling at elevated temperature the resultant core-sheath polymer particles with fixed or permanent base so as to produce a dispersion of particles which, when dried, contain a microvoid which causes opacity in compositions in which they are contained, provided that either (1) said sheath comprises at least about 1% acid functional monomer or (2) said swelling takes place in the presence of solvent. Compositions comprising said core-sheath polymer particles are also disclosed.