Patent ID: 7659348

Claim:
Crosslinked (meth)acrylamide particles in the form of polymer particles having particle sizes of from 1 to 1000 μm, comprising: units derived from an N-alkoxymethyl(meth)acrylamide monomer represented by the formula 2 (wherein X is hydrogen or a methyl group, R 1 is an alkyl group having at least 4 carbon atoms), and units derived from a polyfunctional unsaturated monomer copolymerizable with the monomer represented by the formula 2, wherein a substituent represented by the formula 3 (wherein R 2 is H, R 3 is NH 2 , or R 3 may be a structural unit derived from the N-alkoxymethyl(meth)-acrylamide monomer and bonded to the nitrogen atom in another structural unit derived from the N-alkoxymethyl(meth)acrylamide monomer via a methylene group, and A is a polymer particle) is introduced into the units derived from the N- alkoxymethyl(meth)acrylamide monomer represented by the formula 2.