Abstract: A paper coated resin has been provided which simultaneousy provides coated papers with improved ink receptivity, water resistance and blister resistance in a good balance. The resin is obtainable by introducing alicyclic amino and/or alicyclic epoxy compounds into a polyalkylenepolyamine-urea-aldehyde(epihalohydrin) resin or by introducing alicyclic amino and/or alicyclic epoxy compounds into a polyalkylenepolyamine-urea-aldehyde(epihalohydrin) resin and/or an amine-epihalohydrin resin and reacting or mixing these resins.

Abstract: There is disclosed a process for preparing a sulfonated chitosan wherein C3/C6-position hydroxyl groups are selectively sulfonated with inexpensive sulfonating agents which comprises dissolving or swelling chitosan in an acetic acid in water, regenerating chitosan with an alkaline aqueous solution, washing the regenerated chitosan with water and then with alcohol, immersing the chitosan in a polar solvent and pressing the solvent out of the same and sulfonating the chitosan with SO.sub.3 -DMF complex or ClHSO.sub.3an -DMF complex in a non-polar solvent. Separation of the product can be easily effected by way of filtration and the like.

Abstract: A papermaking additive useful for papermaking in a neutral to alkaline pH region, which comprises as an active component a water-soluble copolymer comprising as constituent monomers (a) 0.1 to 20 mole % of a specific bisquaternary ammonium (meth)acrylamide, (b) 0 to 20 mole % of a specific acrylamide or acrylic ester derivative such as an aminoalkyl (meth)acrylamide or an aminoalkyl (meth)acrylate, or a salt thereof, (c) 50 to 99.9 mole % of acrylamide and/or methacrylamide, and (d) 0 to 10 mole % of an alpha,beta-unsaturated carboxylic acid and/or a salt thereof. The additive increases paper strength and filler retention and size retention.

Abstract: A surface treatment agent for paper comprising a quaternized product of a copolymer containing at least (a) styrene and/or a styrene derivative and (b) N,N-dialkylaminoalkyl (meth) acrylamide is disclosed. This surface treatment agent is excellent in slip prevention and sizing effect, the sizing effect not being impaired at a pH over 7.

Abstract: A novel paper sizing composition comprising a ketene dimer and a hydrophilic vinyl polymer containing an alkylmercaptan having 6-22 carbon atoms. The composition has excellent storage and mechanical stability and sizing effect.

Abstract: A rosin emulsion sizing agent comprising a fortified rosin, an at least partially quarternized product copolymer principal consisting of a (meth)acrylic acid alkylaminoalkyl ester or amide monomer and water exhibits excellent sizing effect in a papermaking system of higher pH, higher water hardness and higher temperature, in which conventional anionic rosin emulsion sizing agents cannot effectively function.

Abstract: A papermaking additive useful for papermaking in a neutral to alkaline pH region which comprises a water-soluble copolymer comprising (a) 1 to 20 mole % of dimethylaminopropyl (meth)acrylamide or its quaternized product, (b) 0.1 to 12 mole % of itaconic acid or its salt, and (c) 98.9 to 68 mole % of acrylamide, the (b)/(a) mole ratio being from 0.1 to 0.6.

Abstract: A rosin emulsion sizing agent comprising 20 to 50% by weight of fortified rosin, 2 to 30% by weight of a saponification product of a styrene/acrylic acid copolymer or a styrene/methacrylic acid copolymer, and the remainder being water.

Abstract: A ketene dimer aqueous dispersion for paper sizing comprising a ketene dimer compound, an acrylamide type polymer having cationic groups and optionally an anionic dispersant and an aqueous medium is disclosed. This dispersion has a ketene dimer content as high as about 25 -30% and good storage stability.