Aqueous silsesquioxane dispersions having low concentrations of reaction byproducts
View Patent ↗Methods of making a composition are disclosed, which comprises: i) forming a dispersion of particles comprising: a) silica, b) a non-volatile cation, and c) water, wherein the non-volatile cation is not ammonium; ii) adding at least one organosilyl coupling agent of formula R 1 —(R 2 —O) 3 —Si where R 1 is selected from the group consisting of a substituted alkyl and unsubstituted alkyl, and R 2 is selected from the group consisting of methyl, ethyl, propyl and butyl, wherein the substituted alkyl of R 1 is not aminoalkyl; iii) reacting the organosilyl coupling agent with the dispersion of particles to form a mixture comprising a silsesquioxane and an alcohol; and iv) removing the alcohol from the mixture by vacuum distillation, wherein final concentration of the alcohol is about 1% by weight or less of the total mixture. Further disclosed are compositions comprising an aqueous dispersion comprising silsesquioxane, a non-volatile cation and an alcohol, and methods of using the composition.
1. A method of making a composition comprising:
i) forming a dispersion of particles comprising: a) silica, b) a non-volatile cation, and c) water, wherein the non-volatile cation is not ammonium;
ii) adding to the dispersion at least one organosilyl coupling agent of formula R 1 —(R 2 —O) 3 —Si where R 1 is selected from the group consisting of a substituted alkyl and unsubstituted alkyl, and R 2 is selected from the group consisting of methyl, ethyl, propyl and butyl, wherein the substituted alkyl of R 1 is not aminoalkyl;
iii) reacting the organosilyl coupling agent with the dispersion of particles to form a mixture comprising a silsesquioxane and an alcohol; and
iv) removing the alcohol from the mixture by vacuum distillation, wherein final concentration of the alcohol is about 1% by weight or less of the total mixture.
2. The method of claim 1 wherein the final concentration of alcohol is about 0.5% by weight or less of the total mixture.
3. The method of claim 1 wherein the final concentration of alcohol is about 1000 ppm or less of the total mixture.
4. The method of claim 1 , wherein the non-volatile cation is selected from the group consisting of lithium, sodium, potassium, cesium, magnesium and calcium.
5. The method of claim 1 , wherein the non-volatile cation is selected from the group consisting of lithium, sodium, potassium and cesium.
6. The method of claim 1 , wherein R 2 is selected from the group consisting of methyl, ethyl and propyl.
7. The method of claim 1 , wherein R 1 is selected from the group consisting of methyl, ethyl, propyl and butyl.
8. The method of claim 1 wherein R 1 is a haloalkyl.
9. The method of any of claims 1 to 8 , further comprising step v) mixing the product produced in step iv) with an aqueous dispersion comprising a fluorochemical resin.
10. The method of claim 9 , further comprising step vi) applying the product of step v) to a carpet.