Fine particulate crosslinked type n-vinylamide resin and microgel,

Abstract

A fine particulate crosslinked type N-vinylcarboxylic acid amide resin having an average particle size of 10 .mu.m or less comprising backbone chains of a homopolymer or copolymer comprising repeating units (A) or (A) and (B) of the formulae: ##STR1## wherein R.sup.1, R.sup.2 and R.sup.3 each independently represent a hydrogen atom or methyl group; X represents a group --COOY, wherein Y represents a hydrogen atom, an alkali metal, a C.sub.1 -C.sub.18 alkyl group or a lower alkyl group substituted with hydroxyl group, a dialkylamino group or a quaternary ammonium group; a group --CONHZ, wherein Z represents a hydrogen atom or a lower alkyl group substituted with a dialkylamino group, a quaternary ammonium group, a sulfonic acid or an alkali metal salt thereof; a cyano group, a 2-ketopyrroridinyl group, a lower alkoxy group, a lower acyl group, a lower alkoxycarbonyl group or a lower alkyl group substituted with sulfonic acid or an alkali metal salt thereof; M represents a hydrogen atom, an alkali metal or an ammonium group, with proviso that when R.sup.3 is a methyl group, X is not a cyano group, a 2-ketopyrrolidinyl group, a lower alkoxy group, a lower acyl group, a lower alkoxycarbonyl group and a lower alkyl group substituted with sulfonic acid or an alkali metal salt thereof, p represents 0 or 1, and the molar ratio of m:n represents 30-100:70-0.