PROCESS OF MAKING WATERBORNE LARGE-SIZE AND STABLE SILICONE RUBBER SUSPENSION AND EXCELLENT SENSORY MATTE COATING THEREBY
A process of preparing a silicone rubber suspension is provided. The process comprises the following steps: 1) preparing an emulsion, the emulsion comprising: a) 100 parts by mass of an organosiloxane with a viscosity between 20 mPa·s and 1,000 mPa·s at 25° C., and having at least two silicon atom-bonded hydroxyl groups in a molecule; b) 3.0 to 10.0 parts by mass of an organoalkoxysilane or a partial hydrolysate thereof; c) 2.0 to 10.0 parts by mass of an alkyl silicate; d) 0.001 to 1.5 parts by mass of a surfactant; and e) 50 to 200 parts by mass of water; and 2) mixing the emulsion with: f) a condensation reaction catalyst; g) 1.0 to 30.0 parts by mass of a surfactant; and h) 0 to 10 parts by mass of water.
1 . A process of preparing a silicone rubber suspension, the process comprising the following steps:
1) preparing an emulsion comprising:
a) 100 parts by mass of an organosiloxane with a viscosity between 20 mPa·s and 1,000 mPa·s at 25 and having at least two silicon atom-bonded hydroxyl groups in a molecule;
b) 3.0-10.0 parts by mass of an organoalkoxysilane or a partial hydrolysate thereof;
c) 2.0-10.0 parts by mass of an alkyl silicate;
d) 0.001-1.5 parts by mass of a surfactant; and
e) 50-200 parts by mass of water; and
2) mixing the emulsion with:
f) a condensation reaction catalyst;
g) 1.0-30.0 parts by mass of a surfactant; and
h) 0-10 parts by mass of water.
2 . The process of claim 1 , wherein an average particle size of silicone rubber particles in the silicone rubber suspension is equal to or greater than 5.5 micrometers.
3 . The process of claim 2 , wherein hardness of the silicone rubber particles is between JIS-A 20 and 60.
4 . The process of claim 1 , wherein the surfactant of step 1) is an anionic surfactant.
5 . The process of claim 1 , wherein the alkyl silicate is of the general formula Si n O n-1 (OR) 2(n+1) where subscript n is an integer greater than 1; and R is an independently selected alkyl group.
6 . The process of claim 1 , wherein greater than 0-15.0 parts by mass of water is added to the emulsion after step 1).
7 . A silicone rubber suspension prepared by the process according to claim 1 .
8 . A method of reducing gloss on a surface of a material, the process comprising coating the surface with the silicone rubber suspension according to claim 7 .
9 . A waterborne coating composition comprising the silicone rubber suspension according to claim 7 .
10 . The process of claim 4 , wherein the surfactant of step 2) is an anionic surfactant.
11 . The process of claim 1 , wherein the surfactant of step 2) is an anionic surfactant.