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:
Jul. 20, 1993
Filed:
Mar. 21, 1991
Tioxide Group PLC, London, GB;
Abstract
A process for the manufacture of core/shell polymer particles comprises forming a core particle containing acid functionality, a first shell around said core of a copolymer of a nonionic monoethylenically unsaturated aromatic monomer and a copolymerisable polar monomer in an amount of at least 15% by weight of the copolymer and having a solubility in water at 20.degree. C. of at least 1% by weight and a second shell around said first shell of a polymer or copolymer of a nonionic monomer having a solubility in water at 20.degree. C. of less than 1% by weight and swelling the particle with a non-volatile alkali to generate one or more vesicles. Preferably each shell contains a polymer or copolymer of styrene.