	US 7,589,153 B2
	Glyoxalated inter-copolymers with high and adjustable charge density
Cornel Hagiopol, Lilburn, Ga. (US); Yuping Luo, Duluth, Ga. (US); David F. Townsend, Grayson, Ga. (US); Clay E. Ringold, Decatur, Ga. (US); and Karla D. Favors, Atlanta, Ga. (US)
Assigned to Georgia-Pacific Chemicals LLC, Atlanta, Ga. (US)
Filed on May 25, 2005, as Appl. No. 11/136,730.
Prior Publication US 2006/0270801 A1, Nov. 30, 2006
Int. Cl. C08F 8/00 (2006.01)

U.S. Cl. 525—194 [525/191; 525/192; 525/218; 162/166; 162/168.3; 162/164.6]

36 Claims

1. A method for producing a glyoxalated inter-copolymer of high charge density useful for strengthening paper, comprising:

(a) reacting a first portion of glyoxal with a blended composition comprising (1) a polyacrylamide having pendant amide groups and (2) a high charge density polymer having pendant glyoxal-reactive groups selected from the group consisting of (A) a polyamidoamine epichlorohydrin polymer; (B) a Michael addition adduct of a polyamidoamine epichlorohydrin polymer and an acrylamide; (C) an interchange reaction inter-copolymer of primary amine-terminated cationic polyamidoamine and neutral polyacrylamide; (D) a cationic polyamidoamine grafted polyacrylamide; and (E) mixtures thereof, to form a first mixture comprising a glyoxalated inter-copolymer of high charge density having separate segments of the polyacrylamide and the high charge density polymer.