Papermaking using cationic starch and naturally anionic polysacchride gums

• US 5,104,487 A
• Filed: 08/16/1990
• Issued: 04/14/1992
• Est. Priority Date: 09/02/1988
• Status: Expired due to Fees

• Current Assignee: BETZ Paperchem Incorporated
• Original Assignee: BETZ Paperchem Incorporated
• Inventors: Schellhamer, Alan J., Taggart, Thomas E., Schuster, Michael A.
• Primary Examiner(s): Chin, Peter
• Application Number:
  US07/568,396
• Time in Patent Office: 607 Days
• Field of Search: 162/175, 162/178, 162/183, 162/168.3, 162/168.2, 162/168.1, 162/164.6
• US Class Current: 162/168.3
• CPC Class Codes: D21H 17/00 Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
• CPC Class Codes: D21H 17/27 Esters thereof
• CPC Class Codes: D21H 17/29 cationic

Abstract

The present invention is directed to a paper having improved properties, a process of producing the paper, and compositions used in the process of producing the paper. The invention generally comprises using a cationic starch in combination with a naturally anionic polysaccharide gum.

Claims

1. In the process of making paper by forming a paper furnish comprised of cellulosic fibers or cellulosic fibers and mineral filler material suspended in water, depositing the furnish on a papermaking wire, and forming a sheet out of the solid components of the furnish while carried on the wire, the improvement wherein there is mixed into the furnish, prior to its being deposited on the wire:

1) about 0.50 to 5 percent of cationic starch based on the dry weight to the total solids is the furnish, followed by;

2) about 5 to 60 percent based on the weight of the cationic starch, of a naturally anionic polysaccharide gum having acid functional groups;

followed by

3) a polymeric fine solids retention aid added in an effective amount to retain fine solids.

2. The process of claim 1 wherein the cellulosic fiber is comprised of 100% virgin chemical pulp, combinations of virgin chemical pulp and mechanical pulp, combinations of virgin chemical pulp and recycled secondary fiber pulp, or 100% recycled secondary fiber pulp.

3. The process of claim 1 wherein the paper furnish is mixed with cationic starch followed by the naturally anionic polysaccharide gum prior to its combination with mineral filler.

4. The process of claim 3 wherein the degree of substitution on the cationic starch is in the range of about 0.01 to 0.10 cationic substituents per anhydroglucose unit in the starch.

5. The process of claim 3 wherein the cationic starch is added to the furnish in the form of an aqueous dispersion containing about 0.10 to 10 percent cationic starch, based on the weight of the dispersion.

6. The process of claim 3 wherein the pH of the furnish when it is deposited on the papermaking wire is in the range of about 3 to 9.

7. The process of claim 3 wherein the cationic starch is derived from one or more of the starch sources consisting of potato, corn, tapioca, rice or wheat.

8. The process of claim 7 wherein the cationic substituents of the starch utilized are selected from the group consisting of tertiary and quaternary amine groups.

9. The process of claim 8 wherein the cationic starch is amphoteric in nature while maintaining a net cationic functionality.

10. The process of claim 3 wherein the polysaccharide anionic gum effective for the purpose is selected from the group of xanthan gum, gum arabic, karaya, gum ghatti, pectin, tragacanth, or algin.

11. The process of claim 10 wherein the acid functional groups of the natural polysaccharide gums utilized consist of pyruvic, galacturonic, or glucuronic acids.

12. The process of claim 11 wherein the average molecular weight of the xanthan or other anionic polysaccharide gum is in the range of 100,000 to 3 million.

13. The process of claim 3 wherein the concentration of the aqueous solution of the anionic polysaccharide gum utilized is about 0.1% to 5.0%.

14. The process of claim 1 wherein the polymeric retention aid is selected from the group consisting of acrylamide monomer, a combination of acrylamide and acrylic acid monomers, and a combination of acrylamide monomer and any cationic moiety.

15. The process of claim 14 wherein the charge density of the polymeric retention aid is within the range of 1% to 40% expressed as the mole percent of cationic or anionic charged moiety.

16. The process of claim 15 wherein the average molecular weight of the polymeric retention aid ranges from 1 million to 18 million.

17. A paper produced in accordance with claim 1.

18. In the process of making paper by forming a paper furnish comprised of cellulosic fibers or cellulosic fibers and mineral filler material suspended in water, depositing the furnish on a papermaking wire, and forming a sheet out of the solid components of the furnish while carried on the wire, the improvement wherein there is mixed into the furnish, prior to its being deposited on the wire:

1) about 0.50 to 5 percent of cationic starch based on the dry weight of the total solids in the furnish, followed by;

2) about 5 to 60 percent, based on the weight of the cationic starch, of a xanthan gum having acid functional groups;

followed by

3) a polymeric fine solids retention aid added in an effective amount to retain fine solids.

19. The process of claim 18 wherein the cellulosic fiber is comprised of 100% virgin chemical pulp, combinations of virgin chemical pulp and mechanical pulp, combinations of virgin chemical pulp and recycled secondary fiber pulp, or 100% recycled secondary fiber pulp.

20. The process of claim 18 wherein the paper furnish is mixed with cationic starch followed by xanthan gum prior to its combination with mineral filler.

21. The process of claim 18 wherein the degree of substitution on the cationic starch is in the range of about 0.01 to 0.10 cationic substituents per anhydroglucose unit in the starch.

22. The process of claim 18 wherein the cationic starch is added to the furnish in the form of an aqueous dispersion containing about 0.10 to 10 percent cationic starch, based on the weight of the dispersion.

23. The process of claim 18 wherein the pH of the furnish when it is deposited on the papermaking wire is in the range of about 3 to 9.

24. The process of claim 18 wherein the cationic starch is derived from one or more of the starch sources consisting of potato, corn, tapioca, rice or wheat.

25. The process of claim 24 wherein the cationic substituents of the starch utilized are selected from the group consisting of tertiary and quaternary amine groups.

26. The process of claim 25 wherein the cationic starch may be amphoteric in nature while maintaining a net cationic functionality.

27. The process of claim 18 wherein the acid functional groups of the natural polysaccharide gums utilized are selected from the group consisting of pyruvic, galacturonic, and glucuronic acids.

28. The process of claim 18 wherein the average molecular weight of the xanthan or other anionic polysaccharide gum are in the range of 100,000 to 3 million.

29. The process of claim 18 wherein the concentration of the aqueous solution of the xanthan gum or other anionic polysaccharide gum utilized is about 0.1% to 5.0%.

30. The process of claim 18 wherein the polymeric retention aid is selected from the group consisting of acrylamide monomer, a combination of acrylamide and acrylic acid monomers, and a combination of acrylamide monomer and any cationic moiety.

31. The process of claim 30 wherein the charge density of the polymeric retention aid is within the range of 1% to 40% expressed as the mole percent of cationic or anionic charged moiety.

32. The process of claim 31 wherein the average molecular weight of the polymeric retention aid ranges from 1 million to 18 million.

33. A paper produced in accordance with claim 18.