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:
Mar. 13, 1990
Filed:
Mar. 27, 1989
Hiroshi Kusano, Yokohama, JP;
Hideaki Kiniwa, Yokohama, JP;
Akihiro Shimura, Machida, JP;
Masahiko Annaka, Mitaka, JP;
Mitsubishi Kasei Corporation, Tokyo, JP;
Abstract
A process for producing crosslinked polymer particles which comprises a first step of polymerizing a polymerizable monomer containing from 0.1 to 2.0% by weight, based on the entire polymerizable monomer, of a crosslinkable monomer in a medium in which the polymerizable monomer is soluble but the resulting polymer is insoluble, to obtain crosslinked polymer particles having a particle size of from 0.8 to 10 .mu.m, and a second step of letting the crosslinked polymer particles absorb from 1 to 50 times by weight of a polymerizable monomer containing from 2 to 100% by weight, based on the entire polymerizable monomer, of a crosslinkable monomer in an aqueous medium, followed by polymerization to obtain crosslinked polymer particles having a particle size of from 1 to 30 .mu.m and a crosslinking degree of from 1.0 to 98%.