Method of producing soft paper products

• US 5,843,278 A
• Filed: 02/14/1997
• Issued: 12/01/1998
• Est. Priority Date: 02/14/1997
• Status: Expired due to Fees

• Current Assignee: Potlatch Corporation
• Original Assignee: Potlatch Corporation
• Inventors: Goyal, Gopal C., Packwood, Robert E. Jr., Minton, Mary L.
• Primary Examiner(s): Chin, Peter
• Application Number:
  US08/799,234
• Time in Patent Office: 655 Days
• Field of Search: 162/9, 162/146, 162/100, 162/157.6, 162/63, 162/70, 162/182, 162/90, 8/116.1, 8/125
• US Class Current: 162/9
• CPC Class Codes: D21C 9/004 inorganic compounds
• CPC Class Codes: D21H 21/22 Agents rendering paper porous, absorbent or bulky

Abstract

A method of producing a soft paper product incudes, a) providing a pulp sheet at a moisture content of no greater than about 10%, the pulp of said sheet not having been previously subjected to dry milling and not being predominately anfractuous; b) treating the pulp sheet at moisture content of no greater than about 10% with liquid ammonia of a concentration of at least 90% for a period of time less than or equal to about 60 seconds effective to increase degree of softness in the sheet of pulp from that existing prior to the treating, the pulp in the treated sheet remaining not predominately anfractuous after said treating; c) forming the treated pulp sheet into a papermaking slurry; and d) feeding the papermaking slurry into the headbox of a paper machine and producing a tissue paper product therefrom which has greater softness than a tissue paper product made from the same pulp which has not been so treated with said ammonia.

Claims

1. A method of producing a soft paper product comprising:

forming a pulp slurry derived from lingnocellosic pulp, the pulp from which said pulp slurry is formed not being predominately anfractuous;

forming the cellulosic pulp slurry into a pulp sheet having a moisture content of no greater than about 15%;

treating the pulp sheet at moisture content of no greater than about 15% with liquid ammonia of a concentration of at least 50% for a period of time effective to increase degree of softness in the sheet of pulp from that existing prior to the treating, the pulp in the treated sheet remaining not predominately anfractuous after said treating;

forming the treated pulp sheet into a papermaking slurry; and

feeding the papermaking slurry into the headbox of a paper machine and producing a paper product therefrom which has greater softness than a paper product made from the same pulp which has not been so treated with said ammonia.

2. The method of producing a paper product of claim 1 wherein the pulp from which said slurry is formed has not been previously subjected to dry milling.

3. The method of producing a paper product of claim 1 wherein the treating comprises treating the pulp sheet with liquid ammonia of a concentration of at least about 75%.

4. The method of producing a paper product of claim 1 wherein the treating comprises treating the pulp sheet with liquid ammonia of a concentration of at least about 90%.

5. The method of producing a paper product of claim 1 wherein the treating comprises treating the pulp sheet with anhydrous liquid ammonia.

6. The method of producing a paper product of claim 1 wherein the moisture content of the pulp sheet being treated is less than or equal to about 10%.

7. The method of producing a paper product of claim 1 wherein the moisture content of the pulp sheet being treated is less than or equal to about 8%.

8. The method of producing a paper product of claim 1 wherein the period of time is less than or equal to about 60 seconds.

9. The method of producing a paper product of claim 1 wherein the period of time is less than or equal to about 30 seconds.

10. A method of producing a soft paper product comprising:

providing a pulp sheet derived from lignocellulosic pulp at a moisture content of no greater than about 15%, the pulp of said sheet not being predominately anfractuous;

treating the pulp sheet at moisture content of no greater than about 15% with liquid ammonia of a concentration of at least 50% for a period of time effective to increase degree of softness in the sheet of pulp from that existing prior to the treating, the pulp in the treated sheet remaining not predominately anfractuous after said treating;

forming the treated pulp sheet into a papermaking slurry; and

feeding the papermaking slurry into the headbox of a paper machine and producing a paper product therefrom which has greater softness than a paper product made from the same pulp which has not been so treated with said ammonia.

11. The method of producing a paper product of claim 10 wherein the pulp sheet was formed from a cellulosic pulp slurry which had not been previously subjected to dry milling.

12. The method of producing a paper product of claim 10 wherein the treating comprises treating the pulp sheet with liquid ammonia of a concentration of at least about 75%.

13. The method of producing a paper product of claim 10 wherein the treating comprises treating the pulp sheet with liquid ammonia of a concentration of at least about 90%.

14. The method of producing a paper product of claim 10 wherein the treating comprises treating the pulp sheet with anhydrous liquid ammonia.

15. The method of producing a paper product of claim 10 wherein the moisture content of the pulp sheet being treated is less than or equal to about 10%.

16. The method of producing a paper product of claim 10 wherein the moisture content of the pulp sheet being treated is less than or equal to about 8%.

17. The method of producing a paper product of claim 10 wherein the period of time is less than or equal to about 60 seconds.

18. The method of producing a paper product of claim 10 wherein the period of time is less than or equal to about 30 seconds.

19. A method of producing a soft tissue paper product comprising:

forming a pulp slurry derived from lignocellulosic pulp, the pulp from which said pulp slurry is formed not having been previously subjected to dry milling and not being predominately anfractuous;

forming the cellulosic pulp slurry into a pulp sheet having a moisture content of no greater than about 10%;

treating the pulp sheet at moisture content of no greater than about 10% with liquid ammonia of a concentration of at least 90% for a period of time less than or equal to about 60 seconds effective to increase degree of softness in the sheet of pulp from that existing prior to the treating, the pulp in the treated sheet remaining not predominately anfractuous after said treating;

forming the treated pulp sheet into a papermaking slurry; and

feeding the papermaking slurry into the headbox of a paper machine and producing a tissue paper product therefrom which has greater softness than a tissue paper product made from the same pulp which has not been so treated with said ammonia.

20. The method of producing a paper product of claim 19 wherein the treating comprises treating the pulp sheet with anhydrous liquid ammonia.

21. The method of producing a paper product of claim 19 wherein the moisture content of the pulp sheet being treated is less than or equal to about 8%.

22. The method of producing a paper product of claim 19 wherein the period of time is less than or equal to about 30 seconds.

23. The method of producing a paper product of claim 19 wherein the treating comprises treating the pulp sheet with anhydrous liquid ammonia, and wherein the period of time is less than or equal to about 30 seconds.

24. A method of producing a soft tissue paper product comprising:

providing a pulp sheet derived from lignocellulosic pulp at a moisture content of no greater than about 10%, the pulp of said sheet not having been previously subjected to dry milling and not being predominately anfractuous;

treating the pulp sheet at moisture content of no greater than about 10% with liquid ammonia of a concentration of at least 90% for a period of time less than or equal to about 60 seconds effective to increase degree of softness in the sheet of pulp from that existing prior to the treating, the pulp in the treated sheet remaining not predominately anfractuous after said treating;

forming the treated pulp sheet into a papermaking slurry; and

feeding the papermaking slurry into the headbox of a paper machine and producing a tissue paper product therefrom which has greater softness than a tissue paper product made from the same pulp which has not been so treated with said ammonia.

25. The method of producing a paper product of claim 24 wherein the treating comprises treating the pulp sheet with anhydrous liquid ammonia.

26. The method of producing a paper product of claim 24 wherein the moisture content of the pulp sheet being treated is less than or equal to about 8%.

27. The method of producing a paper product of claim 24 wherein the period of time is less than or equal to about 30 seconds.

28. The method of producing a paper product of claim 24 wherein the treating comprises treating the pulp sheet with anhydrous liquid ammonia, and wherein the period of time is less than or equal to about 30 seconds.

29. A method of producing a soft paper product comprising:

providing a pulp derived from lignocellulosic pulp, and having a moisture content of no greater than about 15%, the pulp not being predominately anfractuous;

treating the pulp at moisture content of no greater than about 15% with liquid ammonia of a concentration of at least 50% for a period of time effective to increase degree of softness in the pulp from that existing prior to the treating, the pulp remaining not predominately anfractuous after said treating;

forming the treated pulp into a papermaking slurry; and

feeding the papermaking slurry into the headbox of a paper machine and producing a paper product therefrom which has greater softness than a paper product made from the same pulp which has not been so treated with said ammonia.

30. The method of producing a paper product of claim 29 wherein the provided pulp to be treated has not been previously subjected to dry milling.

31. The method of producing a paper product of claim 29 wherein the treating comprises treating the pulp with liquid ammonia of a concentration of at least about 75%.

32. The method of producing a paper product of claim 29 wherein the treating comprises treating the pulp with liquid ammonia of a concentration of at least about 90%.

33. The method of producing a paper product of claim 29 wherein the treating comprises treating the pulp with anhydrous liquid ammonia.

34. The method of producing a paper product of claim 29 wherein the moisture content of the pulp being treated is less than or equal to about 10%.

35. The method of producing a paper product of claim 29 wherein the moisture content of the pulp being treated is less than or equal to about 8%.

36. The method of producing a paper product of claim 29 wherein the period of time is less than or equal to about 60 seconds.

37. The method of producing a paper product of claim 29 wherein the period of time is less than or equal to about 30 seconds.