Sumitomo Chemical Company, Limited

Norio Kondo

Tadayuki Ohmae

Kentaro Mashita

Noboru Yamaguchi

Tadashi Sakurai

Kouichiro Asao

Hisao Takagishi

Shigenao Kawakami

Shigeru Ura

Yoshiya Fukuyama

Hiroshi Horiuchi

Nobuyuki Matsuda

Makoto Nakahara

This invention relates to a process for papermaking which comprises forming a sheet in the presence of a neutral sizing agent and optionally a filler using as a paper quality improver a cationic polymer which is prepared by copolymerizing an acrylamide compound of the formula:

Process for making paper

An aqueous dispersion of a cationic polymer is disclosed, which is obtained by reacting an ethylene copolymer comprising from 40 to 80% by weight of ethylene and from 20 to 60% by weight of at least one aminoalkyl acrylamide comonomer represented by formula (I): ##STR1## wherein R.sub.1 represents a hydrogen atom or a methyl group; R.sub.2 and R.sub.3 each represents a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms; and n represents an integer of from 2 to 4, and having a melt index, as measured in accordance with JIS K-6760, of from 10 to 1,000 g/10 min with hydrochloric acid in water to form a quaternary salt and subsequently reacting the resulting quaternary salt with an epihalohydrin compound through addition reaction. The aqueous dispersion provides a coating film having an improved electrical conductivity or produces effects to simultaneously improve degree of sizing and wet strength of paper.

Aqueous dispersion of cationic polymer

An aqueous dispersion of a cationic polymer is disclosed, which is obtained by reacting an ethylene copolymer comprising from 40 to 80% by weight of ethylene and from 20 to 60% by weight of at least one aminoalkyl acrylamide comonomer represented by formula (I): ##STR1## wherein R.sub.1 represents a hydrogen atom or a methyl group; R.sub.2 and R.sub.3 each represents a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms; and n represents an integer of from 2 to 4,

A durable aqueous solution of a thermosetting resin having a relatively high solid content which imparts a high degree of wet strength to paper, is produced by the reaction of an aliphatic dicarboxylic acid with a polyalkylenepolyamine to form a polyamidopolyamine, which is successively subjected to reaction with epichlorohydrin, the first reaction being carried out using a molar ratio of aliphatic dicarboxylic acid to polyalkylenepolyamine of 1:1.0 to 1.2 and continued until the viscosity at 25.degree. C. of 50% aqueous solution of resulting polyamidopolyamine reaches 400 to 1,000 cps, and the second reaction being carried out using epichlorohydrin in an amount of 1.6 to 1.7 moles per mole of the polyamide secondary amine and continued until the viscosity at 25.degree. C. of 15% aqueous solution of the resulting product reaches 30 to 150 cps.

Production of wet-strength paper with aqueous solutions of cationic

Production of aqueous solutions of cationic thermosetting resins

A transparentizing composition for paper comprising a compound having the formula: ##STR1## or salts thereof and a solvent.

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Osaka, Japan

Norio Kondo