| abstract |
(57) [Summary] [Structure] Acrylamides (a), a vinyl monomer (b) having a cationic group copolymerizable with the component (a), General formula [I] which can be copolymerized with the components (a) and (b): [Wherein R represents a hydrogen atom, an alkyl group, an aryl group or an aralkyl group] and is obtained by reacting at least one kind of vinylphosphonic acids or salts (c) thereof and a crosslinkable compound (d). A papermaking additive containing a water-soluble copolymer. [Effect] Excellent drainage and retention are obtained in the papermaking process, and paper strength and size after papermaking are excellent. |