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:
Aug. 27, 1991
Filed:
Jul. 24, 1990
Jun Hasegawa, Kamakura, JP;
Haruki Oikawa, Yokohama, JP;
Osamu Kobayashi, Yokohama, JP;
Yasuo Kataoka, Yokohama, JP;
Masayoshi Sekiya, Tokyo, JP;
Nippon Zeon Co., Ltd., Tokyo, JP;
Abstract
Hydrophilic fine gel particles, said particles being crosslinked polymer particles comprising 20-94.8% by weight of a monoethylenically unsaturated amide monomer, 5-60.0% by weight of a crosslinkable ethylenically unsaturated monomer, 0.1-30% by weight of an ethylenically unsaturated carboxylic acid, 0.1-50% by weight of an ester monomer of an acrylic or methacrylic acid, and 0-30% by weight of a monomer copolymerizable with the above-mentioned monomers, said particles having a particle diameter in a water-swollen state of 0.1-10 .mu.m and a weight-average particle diameter/number-average particle diameter ratio of 1.2 or less; and a process for producing hydrophilic fine gel particles having a particle diameter in a water-swollen state of 0.1-10 .mu.m and a weight-average particle diameter/number-average particle diameter ratio of 1.2 or less, which comprises copolymerizing a monomer mixture of 20-94.8% by weight of a monoethylenically unsaturated amide monomer, 5-60.0% by weight of a crosslinkable ethylenically unsaturated monomer, 0.1-30% by weight of an ethylenically unsaturated carboxylic acid, 0.1-50% by weight of an ester monomer of an acrylic or methacrylic acid, and 0-30% by weight of a monomer copolymerizable with the above-mentioned monomers using a radical polymerization initiator in a solvent which dissolves these monomers but does not dissolve the resulting polymer.