Method of making low slough tissue products
The present invention is a soft tissue sheet having reduced lint and slough. The tissue sheet comprises papermaking fibers and a synthetic co-copolymer. The synthetic co-polymer has the general structure: wherein R 1 , R 2 , R 3 are independently selected from a group consisting of: H; C 1-4 alkyl radicals; and, mixtures thereof; R 4 is selected from a group consisting of C 1 -C 8 alkyl radicals and mixtures thereof; Z 1 is a bridging radical attaching the R 4 functionality to the polymer backbone; and, Q 1 is a functional group containing at least a cationic quaternary ammonium radical. w, x, y≧1 and the mole ratio of x to (x+y) is about 0.5 or greater.
1. A method of making a soft, low lint tissue sheet, comprising:
(a) forming an aqueous suspension comprising papermaking fibers;
(b) depositing the aqueous suspension of papermaking fibers onto a forming fabric thereby forming a wet tissue sheet;
(c) dewatering the wet tissue sheet thereby forming a dewatered tissue sheet; and,
(d) applying a synthetic co-polymer to the papermaking fibers in an amount from about 0.02 to about 5 weight percent by weight of dried papermaking fibers, said papermaking fibers having a consistency from about 0.2% to about 50%, the synthetic co-polymer having the general structure:
wherein:
R 1 , R 2 , R 3 are independently selected from a group consisting of: H; C 1-4 alkyl radicals; and, mixtures thereof;
R 4 is selected from a group consisting of C 1 -C 8 alkyl radicals and mixtures thereof;
Z 1 is selected from a group consisting of: —O—; —COO—; —OOC—; —CONH—; —NHCO—; and
mixtures thereof; and,
Q 1 is a functional group containing at least a cationic quaternary ammonium radical, wherein w, x, y ≧1 and the mole ratio of x to (x+y) is about 0.5 or greater; and
(e) drying the dewatered tissue sheet, thereby forming a dried treated tissue sheet having reduced geometric mean tensile strength as compared to an untreated tissue sheet and reduced slough as compared to a tissue sheet treated with the same amount of a commercially-available cationic oleylimidazoline debonder, wherein the amount of slough is from about 1.2 to about 3.0 milligrams.
2. The method of claim 1 , wherein the synthetic co-polymer is applied to the wet tissue sheet having a consistency from about 10 percent to about 80 percent.
3. The method of claim 1 , wherein the synthetic co-polymer is applied to the wet tissue sheet having a consistency from about 10 percent to about 50 percent.
4. The method of claim 1 , wherein R 1 is H, R 2 is H, R 3 is H or —CH 3 , and R 4 is selected from the group consisting of: methyl radicals; ethyl radicals; propyl radicals; butyl radicals; and, mixtures thereof.
5. The method of claim 1 , wherein Q 1 of the synthetic co-polymer is derived from monomers selected from the group consisting of: [2-(methacryloyloxy)ethyl] trimethylammonium methosulfate; [2-(methacryloyloxy)ethyl] trimethylammonium ethosulfate; dimethyldiallyl ammonium chloride; 3-acryloamido-3-methyl butyl trimethyl ammonium chloride; vinyl benzyl trimethyl ammonium chloride; 2-[(acryloyloxy)ethyl]trimethylammonium chloride; [2-(methacryloyloxy)ethyl] trimethylammonium chloride; and, mixtures thereof.
6. The method of claim 1 , wherein the mole ratio of x to (x+y) of the synthetic co-polymer is about 0.75 or greater.
7. The method of claim 1 , wherein the mole ratio of x to (x+y) of the synthetic co-polymer is about 0.90 or greater.
8. The method of claim 1 , wherein the synthetic co-polymer has an average molecular weight between about 10,000 to about 5,000,000.
9. The method of claim 1 , wherein the synthetic co-polymer is water soluble or water dispersible.
10. The method of claim 1 , wherein the dried tissue sheet has a Wet Out Time of about 180 seconds or less.
11. The method of claim 1 , wherein the dried tissue sheet has a basis weight of about 5 to about 150 g/m 2 and a bulk of about 2 cm 3 /g or greater.
12. The method of claim 10 , wherein the dried tissue sheet has a bulk of about 4 cm 3 /g or greater.
13. A method of making a soft, low lint tissue sheet, comprising:
(a) forming an aqueous suspension comprising papermaking fibers;
(b) depositing the aqueous suspension of papermaking fibers onto a forming fabric thereby forming a wet tissue sheet;
(c) dewatering the wet tissue sheet thereby forming a dewatered tissue sheet;
(d) applying a synthetic co-polymer to the papermaking fibers in an amount from about 0.02 to about 5 weight percent by weight of dried papermaking fibers, said papermaking fibers having a consistency from about 0.1% to about 50%, the synthetic co-polymer having the general structure:
wherein:
w, x, y ≧1;
the mole ratio of (x+z) to (x+y+z) is greater than 0.5 and the mole ratio of z to (x+z) is from about 0 to about 0.8;
R 1 , R 2 , R 3 are independently selected from a group consisting of: H; C 1-4 alkyl radicals; and, mixtures thereof;
R 4 is selected from a group consisting of C 1 - C 8 alkyl radicals and mixtures thereof;
Z 1 is selected from a group consisting of: —O—; —COO—; —OOC—; —CONH—; —NHCO—; and mixtures thereof;
Q 1 is a functional group containing at least a cationic quaternary ammonium radical; and,
Q 2 is derived from monomers selected from the group of: hydroxyalkyl acrylates;
hydroxyalkyl methacrylates; hydroxyethyl acrylate; polyalkoxyl acrylates; polyalkoxyl methacrylates; diacetone acrylamide; N-vinylpyrrolidinone; N-vinylformamide; and mixtures thereof; and
(e) drying the dewatered tissue sheet, thereby forming a dried treated tissue sheet having reduced geometric mean tensile strength as compared to an untreated tissue sheet and reduced slough as compared to a tissue sheet treated with the same amount of a commercially-available cationic oleylimidazoline debonder, wherein the amount of slough is from about 1.2 to about 3.0 milligrams.
14. The method of claim 13 , wherein the synthetic co-polymer is applied to the wet tissue sheet having a consistency from about 10 percent to about 80 percent.
15. The method of claim 13 , wherein the synthetic co-polymer is applied to the wet tissue sheet having a consistency from about 10 percent to about 50 percent.
16. The method of claim 13 wherein the hydroxyalkyl methacrylate is a hydroxyethyl methacrylate.
17. The method of claim 13 , wherein the polyalkoxyl acrylate is a polyethyleneglycol acrylate.
18. The method of claim 13 , wherein the polyalkoxyl methacrylate is a polyethyleneglycol methacrylate.
19. The method of claim 13 , wherein the mole ratio of (x+z) to (x+y+z) of the synthetic co-polymer is about 0.75 or greater.
20. The method of claim 13 , wherein the mole ratio of (x+z) to (x+y+z) of the synthetic co-polymer is about 0.90 or greater.
21. The method of claim 13 , wherein the mole ratio of z to (x+z) of the synthetic co-polymer is from about 0 to about 0.4.
22. The method of claim 13 , wherein the mole ratio of z to (x+z) of the synthetic co-polymer is from about 0 to about 0.2.
23. The method of claim 13 , wherein the synthetic co-polymer has an average molecular weight between about 10,000 to about 5,000,000.
24. The method of claim 13 , wherein the synthetic co-polymer is water soluble or water dispersible.
25. The method of claim 24 , wherein the dried tissue sheet has a Wet Out Time of about 180 seconds or less.
26. The method of claim 13 , wherein the dried tissue sheet has a basis weight of about 5 to about 100 g/m 2 , and a bulk of about 2 cm 3 /g or higher.
27. The method of claim 26 , wherein the dried tissue sheet has a bulk of about 4 cm 3 /g or greater.