Tape joint compounds with CMC thickener system
View Patent ↗CMC with CMDS greater than or equal to 0.76, optionally with a non-ionic co-thickener or a CMC with CMDS less than 0.75 is used as both the rheology modifier and partial clay substitute in tape joint compounds. This significant reduction of clay level is sufficient to eliminate most of the negative characteristics of clay in joint compound.
1. A ready-mix, drying type tape joint compound composition comprising a binder, a thickener system, a filler, water, and a biocide, wherein the thickener system comprises an uncrosslinked sodium carboxymethylcellulose (CMC) with a degree of substitution (DS) lower limit of 0.76 and a degree of polymerization (DP) lower limit of 1,000 and is present in an amount of 0.01 to 0.6% by weight based on the total weight of the composition.
2. The ready-mix, drying type tape joint compound composition of claim 1 , wherein the thickener system is the uncrosslinked CMC that has a DS lower limit of 0.78.
3. The ready-mix, drying type tape joint compound composition of claim 1 , wherein the thickener system is the uncrosslinked CMC that has a DS lower limit of 0.90.
4. The ready-mix, drying type tape joint compound composition of claim 1 , wherein the thickener system is the uncrosslinked CMC that has a DS upper limit of 1.5.
5. The ready-mix, drying type tape joint compound composition of claim 1 , wherein the thickener system is the uncrosslinked CMC that has a DS upper limit of 1.2.
6. The ready-mix, drying type tape joint compound composition of claim 1 , wherein the thickener system is the uncrosslinked CMC that has a DP lower limit of 5,000.
7. The ready-mix, drying type tape joint compound composition of claim 1 , wherein the thickener system is the uncrosslinked CMC that has a DP lower limit of 6,000.
8. The ready-mix, drying type tape joint compound composition of claim 1 , wherein the thickener system is the uncrosslinked CMC that has a DP upper limit of 25,000.
9. The ready-mix, drying type tape joint compound composition of claim 1 , wherein the thickener system is the uncrosslinked CMC that has a DP upper limit of 20,000.
10. The ready-mix, drying type tape joint compound composition of claim 1 , wherein the thickener system is the uncrosslinked CMC blended with other commercially available CMC products that gives the properties of standard clay-containing joint compounds but in the absence of any clay.
11. The ready-mix, drying type tape joint compound composition of claim 10 wherein the CMC blend includes a CMC with CMDS less than 0.75.
12. The ready-mix, drying type tape joint compound composition of claim 1 , wherein the thickener system includes a co-thickener selected from the group consisting of ethylhdyroxyethyl cellulose (EHEC), hydroxyethyl cellulose (HEC), hydrophobically modified hydroxyethylcellulose, hydroxypropyl methylcellulose (HPMC), methylhydroxyethyl cellulose (MHEC), hydroxypropyl guar, and underivatized guar.
13. The ready-mix, drying type tape joint compound composition of claim 1 , wherein the lower limit of the amount of the thickener system is 0.3 weight %.
14. The ready-mix, drying type tape joint compound composition of claim 1 , wherein the binder is selected from the group consisting of polyvinyl alcohol, ethylene vinyl acetate latex, poly(vinyl acetate) latex, starch, casein, polyacrylamide, and copolymers of acrylamide and acrylic acid.
15. The ready-mix, drying type tape joint compound composition of claim 14 , wherein the binder is present in the amount of lower limit of about 1.0 weight % and an upper limit of about 3.0 weight %.
16. The ready-mix, drying type tape joint compound composition of claim 15 , wherein the binder is present in the amount of about 2.5 weight %.
17. The ready-mix, drying type tape joint compound composition of claim 1 , wherein the filler is selected from the group consisting of calcium carbonate, calcium sulfate dihydrate, and dolomitic limestone, and mixtures thereof.
18. The ready-mix, drying type tape joint compound composition of claim 17 , wherein the filler is calcium carbonate.
19. The ready-mix, drying type tape joint compound composition of claim 1 , wherein the amount of the filler lower limit is about 45 weight %.
20. The ready-mix, drying type tape joint compound composition of claim 1 , wherein the amount of the filler lower limit is about 50 weight %.
21. The ready-mix, drying type tape joint compound composition of claim 1 , wherein the amount of the filler upper limit is about 65 weight %.
22. The ready-mix, drying type tape joint compound composition of claim 1 , wherein in order to maintain the desired pH of 8 to 10, a pH modifier is present.
23. The ready-mix, drying type tape joint compound composition of claim 1 , wherein the biocide is selected from the group consisting of 2[(hydroxymethyl)amino]ethanol and 1,2-benzisothiazolin-3-one.
24. The ready-mix, drying type tape joint compound composition of claim 23 , wherein the biocide is present in an amount lower limit of about 0.05 to about 1.0 weight %.
25. The ready-mix, drying type tape joint compound composition of claim 1 , wherein clay or mica or mixtures thereof are present.
26. The ready-mix, drying type tape joint compound composition of claim 25 , wherein the clay is present and is selected from the group consisting of sepiolite, montmorillonite, bentonite, illite, kaolin, and attapulgite.
27. The ready-mix, drying type tape joint compound composition of claim 26 , wherein the clay is attapulgite.
28. The ready-mix, drying type tape joint compound composition of claim 25 , wherein the clay is present in the amount upper limit of 1.0 weight %.
29. The ready-mix, drying type tape joint compound composition of claim 25 , wherein the clay is present in the amount upper limit of 0.75 weight %.
30. The ready-mix, drying type tape joint compound composition of claim 25 , wherein the clay is present in the amount upper limit of 0.50 weight %.
31. The ready-mix, drying type tape joint compound composition of claim 25 , wherein mica is present in the amount upper limit of 1.5 weight %.
32. The ready-mix, drying type tape joint compound composition of claim 1 , wherein perlite is present.
33. The ready-mix, drying type tape joint compound composition of claim 1 , wherein perlite is present in the mount upper limit of 8.5 weight %.
34. The ready-mix, drying type tape joint compound composition of claim 1 , wherein perlite is present in the mount upper limit of 6.0 weight %.
35. The ready-mix, drying type tape joint compound composition of claim 1 , wherein at least one other ingredient is present selected from the group consisting of air entraining agents, surfactants, humectants, defoamers, and mixtures thereof.
36. The ready-mix, drying type tape joint compound composition of claim 1 , wherein the density of the composition is 7 to 11 pounds per gallon (ppg).
37. The ready-mix, drying type tape joint compound composition of claim 1 , wherein the density of the composition is 12 to 15 ppg.
38. The ready-mix, drying type tape joint compound composition of claim 1 , wherein the water is present in a sufficient amount to provide viscosity of the joint compound composition in the range of from about 300 to about 700 Brabender units (BU).