Soft single-ply tissue having very low sideness

• US 6,051,104 A
• Filed: 08/13/1997
• Issued: 04/18/2000
• Est. Priority Date: 04/01/1994
• Status: Expired due to Term

• Current Assignee: Fort James Corporation (KOCH Industries Incorporated)
• Original Assignee: Fort James Corporation (KOCH Industries Incorporated)
• Inventors: Schulz, Galyn A., Harper, Frank D., Kershaw, Thomas N., Oriaran, T. Philips, Awofeso, Anthony O., Neculescu, Cristian M., Luu, Phuong Van
• Primary Examiner(s): Chin, Peter
• Application Number:
  US08/910,637
• Time in Patent Office: 979 Days
• Field of Search: 162/112, 162/113, 162/125, 162/127, 162/129, 162/130, 162/131, 162/111, 162/109, 162/147, 162/149, 162/179, 162/158, 162/164.1, 162/168.2, 162/168.3, 162/175 , 162/164.3, 162/164.6
• US Class Current: 162/112
• CPC Class Codes: D21F 11/14 Making cellulose wadding, filter or blotting paper
• CPC Class Codes: D21F 11/145 including a through-drying process
• CPC Class Codes: D21F 9/006 paper or board consisting of two or more layers
• CPC Class Codes: D21H 11/14 Secondary fibres working-up waste paper D21C5/02
• CPC Class Codes: D21H 17/07 Nitrogen-containing compounds
• CPC Class Codes: D21H 21/22 Agents rendering paper porous, absorbent or bulky
• CPC Class Codes: Y10T 428/24455 Paper
• CPC Class Codes: Y10T 428/24479 including variation in thickness
• CPC Class Codes: Y10T 442/2311 Coating or impregnation is a lubricant or a surface friction reducing agent other than specified as improving the "hand" of the fabric or increasing the softness thereof

Abstract

A one-ply paper tissue product and a method of making a one-ply paper product combining high strength and softness along with low sidedness. The paper tissue product exhibits a sidedness parameter of less than 0.3 preferably, less than 0.225, a tensile modulus of no more than 32 grams/percent strain, a GM MMD of no more than about 0.225, and a cross directional strength of at least 200 grams per 3 inches. In stratification tissues, these properties are obtained by control of stratification, particularly, chemical stratification and stratification of furnish when appropriate. The tissue has a sidedness parameter value of less than 0.3, preferably, about 0.15 to about less than 0.225. In homogenous tissue, these properties are obtained by adding a strength enhancing agent to separate furnish sources prior to the funish sources being combined, and further, optionally adding the softener to the nascent web.

Claims

1. A process for the manufacture of a soft bathroom tissue product having a serpentine configuration and a low sidedness, which process comprises:

providing a moving foraminous support;

providing a stratified headbox adjacent said moving foraminous support adapted to form a nascent web by depositing furnish upon said moving foraminous support, said stratified headbox having at least two plena;

providing wet pressing means operatively connected to said moving foraminous support to receive said nascent web and for dewatering of said nascent web by overall compaction thereof;

providing a Yankee dryer operatively connected to said moving foraminous support and said wet pressing means and adapted to receive and dry the dewatered nascent web;

one plenum of said headbox being adapted to deposit a Yankee-side stratum of furnish on said moving foraminous support such that, during drying of said nascent web, said Yankee-side stratum will engage said Yankee;

another plenum of said headbox being adapted to deposit a distal stratum of furnish on said moving foraminous support such that, during drying of said nascent web, said distal stratum will be spaced from said Yankee;

supplying a furnish to said one plenum comprising;

cellulosic papermaking fiber chosen from the group consisting of hardwood, softwood, and recycled fibers, and cationic nitrogenous softener/debonder;

supplying another furnish to said other plenum comprising;

cellulosic papermaking fiber chosen from the group consisting of hardwood, softwood, and recycled fibers, and cationic nitrogenous softener/debonder;

forming a nascent web by depositing said one furnish and said other furnish on said moving foraminous support, the overall concentration of cationic nitrogenous softener/debonder in said nascent web being controlled to between about 1 to about 8 lbs/ton on a dry fiber basis;

the concentration of cationic nitrogenous softener/debonder in said Yankee-side stratum to from about 2% to no more than 75% of the concentration of said cationic nitrogenous softener/debonder in the distal stratum;

wet pressing said nascent web;

transferring said nascent web to said Yankee dryer, adhering said web to said Yankee, and creping said web from said Yankee;

recovering a creped, dried bathroom tissue product; and

forming a roll of single-ply tissue;

controlling the relative amounts of softwood fibers, recycle fibers, hardwood fibers, and cationic nitrogenous softener/debonder in each of said strata wherein said tissue comprising at least two differentiated strata which do not delaminate from each other such that said creped, dried tissue exhibits;

a sidedness parameter of less than 0.3, a tensile modulus of no more than 32 grams/percent strain, a GM MMD friction of no more than about 0.225, and a cross directional dry tensile strength of at least 200 grams per 3 inches.

2. The tissue of claim 1 wherein the distal stratum is the air side stratum.

3. The process of claim 1 wherein the basis weight of the tissue is controlled to be at least ten pounds per three thousand square foot ream.

4. The process of claim 1 wherein the basis weight of the tissue is controlled to be in the range of about 10 to about 27 pounds per three thousand square foot ream.

5. The process of claim 1 wherein optionally strength enhancing agent is present in the tissue.

6. The process of claim 1 wherein the strength enhancing agent is water soluble starch.

7. The process of claim 6 wherein amylose and amylopectin content of the starch is in the range of about 1 to about 30 and about 99 to about 70 percent respectively.

8. The process of claim 1 wherein the sidedness parameter of the tissue is controlled to be in the range of about 0.1 to about 0.225.

9. The process of claim 1 wherein the crepe angle is controlled to form an angle of less than 80°

.

10. The process of claim 9 wherein the crepe angle is controlled to form an angle of about 70 to about 78°

.

11. The process of claim 1 wherein about 0.1 to about 10 pounds of the cationic softener/debonder are added for each ton of furnish.

12. The process of claim 1 wherein the nitrogenous softener/debonder is selected from the group consisting of imidazolines, amido amine salts, linear amido amines, tetravalent ammonium salts, and mixtures thereof.

13. The process of claim 12 wherein the salt has the following structure:

space="preserve" listing-type="equation">[(RCO).sub.2 EDA]HX

wherein EDA is a diethylenetriamine residue, R is the residue of a fatty acid having from 12 to 22 carbon atoms, and X is an anion.

14. The process of claim 12 wherein the salt has the following structure:

space="preserve" listing-type="equation">[(RCONHCH.sub.2 CH.sub.2).sub.2 NR'"'"']HX

wherein R is the residue of a fatty acid having from 12 to 22 carbon atoms, R'"'"' is a lower alkyl group, and X is an anion.

15. The process of claim 12 wherein the softener/debonder is a mixture of linear amido amines and imidazolines of the following structure:

##STR4## wherein X is an anion.

16. The process of claim 1 wherein the nitrogenous adhesive is applied to the steel side of the Yankee.

17. The process of claim 16 wherein about 0.1 to about 0.3 pounds of the nitrogenous adhesive are added for each ton of furnish.

18. The process of claim 16 wherein the nitrogenous adhesive is a glyoxylated polyacrylamide or a polyaminoamide.

19. The process of claim 18 wherein the glyoxylated polyacrylamide moiety is in the form of a blend or in the form of a terpolymer comprising polyacrylamide of at least 40 weight percent and glyoxal of at least 2 weight percent.

20. The process of claim 1 wherein the tissue is embossed by having the hard pattern roll of the embossing nip engage the Yankee side of the sheet while the rubber roll in the nip engages the air side.

21. The process of claim 1 wherein the cationic nitrogen softener/debonder is sprayed to the first stratum of the chemically stratified web.