Process and compositions for paper-making

Patent metadata

Field	Value
Publication number	US-9873983-B2
Application number	US-201415021479-A
Country	US
Kind code	B2
Filing date	Sep 12, 2014
Priority date	Sep 12, 2013
Publication date	Jan 23, 2018
Grant date	Jan 23, 2018

Abstract

The invention provides a process for paper-making comprising adding to pulp slurry at least a first aqueous liquid and a second aqueous liquid so as to obtain a paper stock; forming the paper stock so as to obtain a wet paper web; pressing and draining the wet paper web so as to obtain a wet paper sheet; and drying the wet paper sheet so as to obtain a paper sheet. Correspondingly, the invention provides an aid composition for paper-making.

First claim

The invention claimed is:

1. A process for paper-making comprising:
(a) adding to pulp slurry at least a first aqueous liquid and a second aqueous liquid so as to obtain a paper stock;
(b) forming the paper stock so as to obtain a wet paper web;
(c) pressing and draining the wet paper web so as to obtain a wet paper sheet; and
(d) drying the wet paper sheet so as to obtain a paper sheet,
wherein,
the first aqueous liquid contains a dialdehyde-modified polyacrylamide-type strengthening agent and water, and the second aqueous liquid contains an amphoteric polyacrylamide-type strengthening agent and water;
the dialdehyde-modified polyacrylamide-type strengthening agent has a weight average molecular weight of 100,000-2,000,000 Dalton;
the amphoteric polyacrylamide-type strengthening agent has a weight average molecular weight of 100,000-10,000,000 Dalton; and
the dialdehyde-modified polyacrylamide-type strengthening agent and the amphoteric polyacrylamide-type strengthening agent have a weight ratio of 25:75-75:25.

2. The process of claim 1 , wherein
the dialdehyde-modified polyacrylamide-type strengthening agent is a cationic dialdehyde-modified polyacrylamide-type strengthening agent, which is a dialdehyde-modified copolymer comprising acrylamide monomer and cationic monomer.

3. The process of claim 2 , wherein the dialdehyde of the dialdehyde-modified copolymer is glyoxal.

4. The process of claim 2 , wherein the cationic monomer is diallyldimethylammonium chloride.

5. The process of claim 2 , wherein the acrylamide monomer is acrylamide.

6. The process of claim 1 , wherein the dialdehyde-modified polyacrylamide-type strengthening agent has a weight average molecular weight of 100,000-300,000 Dalton.

7. The process of claim 1 , wherein the amphoteric polyacrylamide-type strengthening agent is a copolymer comprising acrylamide monomer, cationic monomer and anionic monomer.

8. The process of claim 1 , wherein the cationic monomer is selected from diallyldimethylammonium chloride, N-(3-dimethylaminopropyl)acrylamide, trimethyl-2-acroyloxyethylammonium chloride, 2-(dimethylamino)ethyl methacrylate, and combinations thereof.

9. The process of claim 7 , wherein the anionic monomer is selected from acrylic acid, itaconic acid, salts thereof, and combinations thereof.

10. The process of claim 1 , wherein the second aqueous liquid contains substantially 0% of aldehyde.

11. The process of claim 1 , wherein the first aqueous liquid and the second aqueous liquid are mixed prior to the addition into the pulp slurry.

12. The process of claim 1 , wherein the total amount of the first aqueous liquid and the second aqueous liquid added is 0.01-50 kg/ton dry fiber, based on the weight ratio of the total amount of the dialdehyde-modified polyacrylamide-type strengthening agent and the amphoteric polyacrylamide-type strengthening agent relative to the dry fiber in the pulp.

13. The process of claim 1 , wherein the solid content of the dialdehyde-modified polyacrylamide-type strengthening agent in the first aqueous liquid is 0.01-50 wt %.

14. The process of claim 1 , wherein the solid content of the amphoteric polyacrylamide-type strengthening agent in the second aqueous liquid is 0.01-50 wt %.

15. A composition for paper-making comprising one or more cationic or anionic or amphoteric dialdehyde-modified polyacrylamide-type strengthening agent and one or more amphoteric polyacrylamide-type strengthening agent;
wherein:
the dialdehyde-modified polyacrylamide-type strengthening agent has a weight average molecular weight of 100,000-2,000,000 Dalton;
the amphoteric polyacrylamide-type strengthening agent has a weight average molecular weight of 100,000-10,000,000 Dalton; and
the dialdehyde-modified polyacrylamide-type strengthening agent and the amphoteric polyacrylamide-type strengthening agent added in the step (h) have a weight ratio of 25:75-75:25.

16. The composition of claim 15 , wherein
the dialdehyde-modified polyacrylamide-type, strengthening agent is a cationic dialdehyde-modified polyacrylamide-type strengthening agent, which is a dialdehyde modified copolymer comprising acrylamide monomer and cationic monomer.

17. The composition of claim 16 , wherein the dialdehyde of the dialdehyde-modified copolymer is glyoxal.

18. The composition of claim 16 , wherein the cationic monomer is diallyldimethylammonium chloride.

19. The composition of claim 16 , wherein the acrylamide monomer is acrylamide.

20. The composition of claim 15 , wherein the dialdehyde-modified polyacrylamide-type strengthening agent has a weight average molecular weight of 100,000-300,000 Dalton.

21. The composition of claim 15 , wherein
the amphoteric polyacrylamide-type strengthening agent is a copolymer comprising acrylamide monomer, cationic monomer and anionic monomer.

22. The composition of claim 21 , wherein the cationic monomer is selected from diallyldimethylammonium chloride, N-(3-dimethylaminopropyl)acrylamide, trimethyl-2-acroyloxyethylammonium chloride, 2-(dimethylamino)ethyl methacrylate, and combinations thereof.

23. The composition of claim 21 , wherein the anionic monomer is selected from acrylic acid, itaconic acid, salts thereof, and combinations thereof.

24. The composition of claim 21 , wherein the composition contains substantially 0% aldehyde.

25. The composition of claim 15 , wherein the total solid content of the dialdehyde-modified polyacrylamide-type strengthening agent and the amphoteric polyacrylamide-type strengthening agent in the aid composition for paper-making is 0.01-60 wt %.

26. The composition of claim 15 , further comprising water.

Assignees

• Ecolab Usa Inc

Inventors

• Zhu Bo
• Zhang Meng
• Li Jun
• Xu Na
• Zhao Yulin

Classifications

• D21H17/375 Primary

  Poly(meth)acrylamide · CPC title

• D21H21/20 Primary

  Wet strength agents · CPC title

• D21H17/37

  Polymers of unsaturated acids or derivatives thereof, e.g. polyacrylates · CPC title