Paper strength improving composition, manufacture thereof and use in paper making

Patent metadata

Field	Value
Publication number	US-11453979-B2
Application number	US-201817055152-A
Country	US
Kind code	B2
Filing date	May 14, 2018
Priority date	May 14, 2018
Publication date	Sep 27, 2022
Grant date	Sep 27, 2022

Abstract

Embodiments of the present invention relate to a method of making a paper comprising the steps of: a) providing a cationic wet strength resin comprising a polyamidoamine epihalohydrin, a condensation copolymer of epihalohydrin and amine, or combination thereof; b) providing an anionic polymer; c) co-mixing the cationic wet strength resin and the anionic polymer to provide a composition comprising polyelectrolyte complexes; d) providing an aqueous pulp slurry, draining the aqueous pulp slurry on a screen to form a wet fiber web, and drying the wet fiber web to obtain the paper, wherein said co-mixed composition is introduced to the aqueous pulp slurry or on the formed wet fiber web. Embodiments of the present invention further relates to a paper wet strength composition, its use in paper making and a paper obtainable therefrom.

First claim

The invention claimed is:

1. A method of making a paper comprising the steps of:
a) providing a cationic wet strength resin comprising a polyamidoamine epihalohydrin, a condensation copolymer of epihalohydrin and amine, or a combination thereof,
b) providing an anionic polymer,
c) co-mixing the cationic wet strength resin and the anionic polymer to provide a composition comprising polyelectrolyte complexes,
d) providing an aqueous pulp slurry, draining the aqueous pulp slurry to form a wet fiber web, and drying the wet fiber web to obtain the paper,
wherein said co-mixed composition is introduced to the aqueous pulp slurry or on the formed wet fiber web,
and further wherein the anionic polymer has a standard viscosity of about 1.1 to 6 cP, measured at 0.1 weight-% polymer concentration in 1 M NaCl, at 25° C. and pH 8.0—8.5, using Brookfield DVII T viscometer.

2. The method according to claim 1 , wherein the anionic polymer comprises an anionic synthetic polymer, an anionic polysaccharide, or any combination thereof.

3. The method according to claim 2 , wherein the anionic synthetic polymer comprises a copolymer of non-ionic monomers and anionic monomers, a homopolymer of anionic monomers, a partially or completely hydrolysed poly(meth)acrylamide, an anionic glyoxalated polyacrylamide, or any combination thereof.

4. The method according to claim 3 , wherein the copolymer of non-ionic monomer and anionic monomer has a molar ratio of anionic monomer to non-ionic monomer in the range of 5:95—95:5.

5. The method according to claim 2 , wherein the anionic polysaccharide comprises anionic cellulose, anionic starch, anionic vegetable gum, anionic microfibrillar cellulose, or any combination thereof.

6. The method according to claim 1 , wherein the anionic polymer has a charge density of about −0.1 to −10 meq/g (dry), as measured at pH 7.

7. The method according to claim 1 , wherein the cationic wet strength resin has a weight average molecular weight of about 150 000 to 1 000 000 Dalton.

8. The method according to claim 1 , wherein the cationic wet strength resin has a charge density of about 1.5 to 6.0 meq/g, as measured at pH 4.

9. The method according to claim 1 , wherein the cationic wet strength resin comprises a polyamidoamine epihalohydrin resin.

10. The method according to claim 9 , wherein the polyamidoamine epihalohydrin has an epihalohydrin:amine molar ratio of at least 0.80.

11. The method according to claim 1 , wherein the weight ratio of the anionic polymer to the cationic wet strength resin is about 5:95 to 50:50.

12. The method according to claim 1 , wherein the solids content of the cationic wet strength resin is at least 15 weight-%, before co-mixing with the anionic polymer.

13. The method according to claim 1 , wherein the co-mixed composition of step c) is diluted with water before introducing to the aqueous pulp slurry or on the formed wet fiber web; preferably the co-mixed composition of step c) is diluted to a solids content of at most 5 weight-%.

14. The method according to claim 1 , wherein the co-mixed composition has a net cationic charge, as measured at pH 4; preferably the co-mixed composition has a charge density of at least 0.01 meq/g, as measured at pH 4.

15. The method according to claim 1 , wherein the co-mixed composition is introduced to the aqueous pulp slurry or on the formed wet fiber web at most 2 hours after initiation of co-mixing.

16. The method according to claim 1 , wherein the paper is selected from tissue, towel, carrier board, linerboard, fluting, liquid packaging board, folding box board, solid bleached sulfate board, solid unbleached sulfate board, and white lined chipboard.

Assignees

• Kemira Oyj

Inventors

• Luo Yuping
• Chen Junhua
• Dang Zheng

Classifications

• D21H19/24

  comprising macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• D21H17/28

  Starch · CPC title

• D21H17/49

  with compounds containing hydrogen bound to nitrogen · CPC title

• D21H23/04

  Addition to the pulp; After-treatment of added substances in the pulp · CPC title

• D21H21/20 Primary

  Wet strength agents · CPC title