Wax emulsions for gypsum products
Emulsions, useful for imparting water resistance to gypsum products are disclosed. The emulsions of the invention include at least one wax, an alkyl phenol and a hydrophyllic metallic salt, preferably magnesium sulfate. The emulsions of the invention do not require the addition of a starch compound and therefore exhibit enhanced stability even at higher solids content then compared to prior art emulsions.
1. An emulsion for providing water-resistance to a gypsum product comprising at least one wax, an alkyl phenol and magnesium sulfate.
2. The emulsion of claim 1 wherein the magnesium sulfate is in an amount of about 0.05% to about 5% by weight, based on the total weight of the emulsion.
3. The emulsion of claim 1 wherein the magnesium sulfate is in an amount of about 0.1% to about 2.5% by weight, based on the total weight of the emulsion.
4. The emulsion of claim 1 wherein the magnesium sulfate is in an amount of about 0.1% to about 1.0% by weight, based on the total weight of the emulsion.
5. The emulsion of claim 1 , provided however, that no starch component is added.
6. The emulsion of claim 1 wherein the at least one wax is in an amount of about 25% to about 40% by weight based on the total weight of the emulsion, and wherein the emulsion further comprises a saponifiable wax in an amount of about 2.5% to about 4.5% by weight, based on the total weight of the emulsion.
7. The emulsion of claim 6 further comprising an alkyl phenol in an amount of about 0.1% to about 1.0% by weight, based on the total weight of the emulsion.
8. The emulsion of claim 6 further comprising a polynaphthalenesulfonic acid in an amount of about 0.25% to about 5.0% by weight based on the total weight of the emulsion; water in an amount of about 55% to about 65% by weight based on the total weight of the emulsion; an alkali metal hydroxide in an amount or about 0.5% to about 1.5% by weight, based on the total weight of the emulsion.
9. The emulsion of claim 1 , wherein the emulsion is stable for at least 1 month.
10. The emulsion of claim 1 having a solids content of greater than 45% by weight, based on the total weight of the emulsion.
11. A method for making an emulsion useful in providing water-resistance to a gypsum product, comprising the steps of
(a) combining a first mixture comprising at least one wax and an alkyl phenol with a second mixture comprising magnesium sulfate and water,
(b) combining the first mixture and the second mixture to form a resultant mixture, and
(c) homogenizing the resultant mixture.
12. The method of claim 11 wherein the second mixture comprises magnesium sulfate in an amount of about 0.05% to about 5% by weight, based on the total weight of the emulsion.
13. The method of claim 11 , provided however, that the emulsion does not contain a starch compound.
14. The method of claim 11 wherein the first mixture comprises at least one wax in an amount of about 25% to about 40% by weight based on the total weight of the emulsion, and wherein the first mixture further comprises a saponifiable wax in an amount of about 2.5% to about 4.5% by weight, based on the total weight of the emulsion.
15. The method of claim 14 wherein the first mixture comprises the alkyl phenol in an amount of about 0.1% to about 1.0% by weight, based on the total weight of the emulsion.
16. A gypsum product comprising gypsum and the emulsion of claim 1 .
17. The gypsum product of claim 16 wherein the magnesium sulfate is in an amount of about 0.05% to about 5% by weight, based on the total weight of the emulsion.
18. The gypsum product of claim 16 wherein the magnesium sulfate is in an amount of about 0.1% to about 2.5% by weight, based on the total weight of the emulsion.
19. The gypsum product of claim 16 wherein the magnesium sulfate is in an amount of about 0.1% to about 1.0% by weight, based on the total weight of the emulsion.
20. The gypsum product of claim 16 , provided however, that the emulsion does not contain a starch component.