Abstract: An agent for improving surface quality of paper comrising an acrylamide resin composition obtained by hydrolyzing an acrylamide resin which is obtained by polymerizing an acrylamide monomer in the presence of a urea compound, or copolymerizing an acrylamide monomer and an acrylonitrile monomer; an acrylamide monomer and a cross-linking agent; or an acrylamide monomer, an acrylnitrile monomer and a cross-linking agent in the presence of a urea compound. This agent provides paper with excellent surface strength, tensile strength and internal strength far better than conventional paper quality improving agents.

Abstract: A novel additive for papermaking is disclosed. The additive comprises an aqueous solution of a copolymer obtained by reacting (a) an acrylamide, (b) a vinyl monomer which is copolymerizable with component (a) and has a cationic group, (c) at least one of vinyl monomers which are copolymerizable with component (a) and (b) and have 2, 3 or 4 carboxyl groups in a molecule thereof and/or a salt thereof, optionally (e) a nonionic monomer which is copolymerizable with components (a), (b) and (c) if desired, and (d) a cross-linking compound, in the presence of (f) at least one of ethylene glycol, diethylene glycol, diethanolamine and glycerin.This novel additive for papermaking is able to achieve excellent freeness and retention in the process of papermaking and provides paper with increased strength.

Abstract: A refining assisting agent comprising sulfonated chitosan has been provided. With the addition of the sulfonated chitosan according to the present invention, power needed in the refining can be remarkably reduced compared with that needed in the conventional refining. In addition, the refining assisting additive improves paper strength.

Abstract: The present invention provides a paper sizing composition comprising a rosin material and cationic acrylamide and/or methacrylamide polymers having hydrophobic groups wherein said rosin material is directly emulsified in water with said polymers. The sizing composition has an improved storage stability and exhibits an excellent sizing performance in the acidic through neutral pH range.

Abstract: This invention provides a rosin emulsion sizing agent for papermaking comprising a fortified or unfortified rosin-epoxy compound obtained by reacting a rosin and an epoxy compound, wherein the rosin-epoxy compound is dispersed in water with the aid of an emulsifying and dispersing agent, and paper sized therewith and a method of sizing using the same. The rosin emulsion sizing agent of the present invention exhibits an distinguished sizing effect in neutral papermaking systems even when calcium carbonate is contained therein and is excellent in mechanical and storage stabilities while causing little foaming in the papermaking system. In addition, the sizing agent presents no significant difficulties in its production.