Patent ID: 7482417

Claim:
A papermaking chemical, containing a (meth)acrylamide polymer produced by polymerizing a monomer (a) expressed by the following general formula 1, the following monomer (b), the following monomer (c1), the following monomer (c2), and a crosslinking agent (d): (a) general formula 1: where R 1 is a C 1 to C 4 alkylene group, R 2 to R 4 are each independently selected from the group consisting of a hydrogen atom a C 22 or lower alkyl group a C 22 or lower hydroxyalkyl group, a C 22 or lower alkylamine group, a C 22 or lower alkyl ether group, a C 22 or lower alkyl ester group, a C 22 or lower alkylamide group, a C 22 or lower aryl group, or a group that has a cyclic structure when any two of R 2 or R 4 bond together, and X— is an anion of an inorganic acid or an organic acid); (b) a (meth)acrylamide; (c1) a (meth)allylsulfonic acid (salt); (c2) an ionic monomer other than the monomer (a) and the monomer (c1).