PREPARATION OF WATER-SOLUBLE COPOLYMERS CONTAINING VINYLAMINE UNITS, AND THEIR USE AS WET STRENGTH AGENTS AND DRY STRENGTH AGENTS FOR PAPER

摘要

Abstract of the Disclosure: Water-soluble copolymerscontaining copolymerized vinylamine units are preparedby copolymerizing a) from 95 to 10 mol% of N-vinylform-amide and b) from 5 to 90 mol% of an ethylenically un-saturated monomer from the group consisting of vinylacetate, vinyl propionate, C1-C4-alkyl vinyl ethers,the esters, nitriles and amides of acrylic acid and meth-acrylic acid and N-vinylpyrrolidone, and then eliminatingfrom 30 to 100 mol% of the formyl groups from the co-polymer. Preferred copolymers are copolymers of N-vinyl-formamide and vinyl acetate, in which from 30 to 100 mol%of the monomer units are hydrolyzed. The copolymers areused in papermaking to increase the dry strength and wetstrength of the paper.