Calcium hypochlorite composition
View Patent ↗Describes a composition comprising a mixture of (1) a major amount of calcium hypochlorite, e.g., hydrated calcium hypochlorite, and (2) a minor amount of calcium hypochlorite-compatible hydrophobic additive (other than discrete particulate Group IIA or IIIA metal stearates) in amounts sufficient to provide the composition with reduced hydrophilic properties. The composition has a solution rate in water at standard conditions that is less than the calcium hypochlorite used to prepare the composition, but sufficient for the intended application. Describes also calcium hypochlorite compositions in which the hydrophobic additive is an organo-silicon material, or a metal oxide, e.g., amorphous precipitated silica, treated with a hydrophobizing agent, such as an organo-silicon material, e.g., an organo-silane and/or organo-siloxane material.
1. A composition comprising a mixture of:
(i) a major amount of solid calcium hypochlorite, and
(ii) an amount of hydrophobic additive that is sufficient to provide a calcium hypochlorite composition having reduced hydrophilic properties, said composition being substantially free of discrete particulate Group IIA and IIIA metal stearate, said hydrophobic additive being a particulate calcium hypochlorite-compatible carrier material chosen from inorganic metal oxide and clay material, the surface of which has been treated with hydrophobizing agent represented by one of the following general formulae,
R 1 a MX 4−a I
R 2 2n+2 Si n O n−1 II
R 1 2m Si m O m III
(R 3 Si) 2p O 3p IV
wherein (a) M is independently chosen from silicon, titanium or zirconium; (b) each R 1 is independently chosen from a saturated hydrocarbon group containing from 1 to 18 carbon atoms; (c) each X is independently chosen from alkoxy containing from 1 to 12 carbon atoms, or acyloxy containing from 1 to 12 carbon atoms; (d) a is a number chosen from 1 to 4, (e) each R 2 is independently chosen from halo, hydroxy, or R 1 with the proviso that at least 50 mole percent of the R 2 substituents are saturated hydrocarbon groups; (f) n is a number of from 2 to 10,000; (g) m is a number of from 3 to 20, (h) R 3 is chosen from an aliphatic, cycloaliphatic or aryl hydrocarbon containing from 1 to 6 carbon atoms, cyclohexyl, vinyl or phenyl, or a glycidoxy alkyl group, and (i) p is a number chosen from 4 to 1000, the weight ratio of hydrophobizing agent to carrier material being from 1:1 to 1:20.
2. The composition of claim 1 wherein the solution rate in water of the calcium hypochlorite composition is less than the solution rate of the calcium hypochlorite used to prepare the composition.
3. The composition of claim 2 wherein the hydrophobic additive present in the composition ranges from 0.1 to 5 weight percent, based on the total weight of the composition.
4. The composition of claim 1 wherein the hydrophobizing agent is chosen from organo-silane materials or organo-siloxane materials.
5. The composition of claim 4 wherein the inorganic metal oxide is an oxide of a metal chosen from the metals in Periods 2, 3 or 4 of Groups IIIA, IVA (except carbon) and IVB of the Periodic Classification of the Elements, and the clay material is a hydrous silicate of aluminum, magnesium or calcium.
6. The composition of claim 5 wherein the inorganic metal oxide is chosen from the oxides of boron, aluminum, silicon, titanium or zirconium.
7. The composition of claim 5 wherein the inorganic metal oxide is precipitated silica.
8. The composition of claim 7 wherein the precipitated silica is treated with an organo-siloxane.
9. The composition of claim 8 wherein the organo-siloxane treated precipitated silica represents from 0.1 to 2 weight percent of the composition.
10. The composition of claim 9 wherein the composition is in the form of a tablet.
11. The composition of claim 10 wherein the calcium hypochlorite of the composition has a free available chlorine content that ranges from 45 to 80 percent.
12. The composition of claim 11 further comprising from 2 to 2.5 weight percent of added calcium hydroxide, magnesium hydroxide, aluminum hydroxide or magnesium silicate, based on the total weight of the composition.
13. The composition of claim 1 wherein the mixture comprises at least 75 weight percent of hydrated calcium hypochlorite and not more than 2 weight percent of hydrophobic additive, said hydrophobic additive being a particulate calcium hypochlorite-compatible silicon oxide carrier material, the surface of which has been treated with organo-silicon hydrophobizing agent, the weight ratio of hydrophobizing agent to silicon oxide carrier being from 1:3 to 1:6.
14. The composition of claim 13 wherein the solution rate of the composition in water is diminished to not more than 50 to 70 percent of the hydrated calcium hypochlorite.
15. The composition of claim 13 wherein the composition comprises at least 90 weight percent of hydrated calcium hypochlorite.
16. The composition of claim 13 wherein the particulate silicon oxide carrier material is precipitated silica.
17. The composition of claim 16 wherein the organo-silicon material is chosen from silicon oil having a number average molecular weight of from 150 to 450,000 or polyalkylsilsesquioxane.
18. The composition of claim 17 wherein the organo silicon material is a silicon oil having a number average molecular weight of from 400 to 15,000, and the polyalkylsilesquioxane is polymethylsilsesquioxane.
19. The composition of claim 18 wherein the precipitated silica is treated with organo polysiloxane.
20. The composition of claim 19 wherein the composition is in the form of a tablet.