Granted Patent B2

US 9,879,380 · App. 15/447,726 · Granted Jan 30, 2018

Abstract

Claims (10)

1. A method of improving dry strength and/or drainage of a paper or paperboard comprising:

adding to a paper or paperboard furnish, a graft copolymer composition of a vinyl monomer and a functionalized vinylamine-containing base polymer wherein the functionalized vinylamine-containing base polymer comprises randomly distributed repeating monomer units having the formula (I), (II) and (III),

wherein R is a reacted α, β-unsaturated alkyl carbonyl compound through Michael addition by vinylamine in the polymer; n, p and q are the numbers indicating mole % of the repeating units of formula (I), (II) and (III) present in the functionalized vinylamine-containing base polymer; and

wherein n is from about 5 mole % to about 98 mole %, p is from about 1 mole % to about 80 mole %, q is from about 1 mole % to about 30 mole % the mole ratio of the functionalized vinylamine-containing base polymer to the vinyl monomer in the graft polymer is in the range of from about 10:90 to about 50:50; and

forming the paper or paperboard.

2. The method according to claim 1 , wherein the composition is used in combination with one or more additives.

3. The method according to claim 2 , wherein the one or more additives is an aqueous dispersion of a cationic amide-containing polymer.

4. The method according to claim 3 , wherein the mole ratio of cationic amide-containing polymer to vinylamine-containing graft copolymer is from about 2:98 to about 40:60.

5. The method according to claim 2 , wherein the one or more additives is selected from the group consisting of cationic, anionic, amphoteric, nonionic synthetic and natural polymers.

6. The method according to claim 5 , wherein the anionic additive is selected from the group consisting of a copolymer containing acrylic acid, a copolymer of acrylamide and acrylic acid, and a carboxyl methyl cellulose.

Assignments (14)