Polysiloxane Modified Titanium Dioxide
A particle of titanium dioxide treated with a polysiloxane is disclosed. One or more silicon atoms of the polysiloxane is substituted with an alkylene group terminating with a silyl group containing three substituents selected from the group consisting of hydroxy, halo, alkoxy, acetoxy, and mixtures thereof. These treated particles are blended with organic polymers to form a polyethylene polymer matrix having dispersed therein at least 55 wt % polysiloxane modified titanium dioxide particles.
1 . A particle comprising titanium dioxide treated with a polysiloxane, wherein the polysiloxane has the general formula:
wherein each of R1 and R2 is independently selected from the group consisting of C1 to C14 hydrocarbyl; each R3 is selected from the group consisting of hydroxyl, halo, alkoxy, and acetoxy; R4 is selected from the group consisting of C1 to C22 hydrocarbyl; x is an integer from 1 to 22; m is an integer from 0 to 500; and n is an integer from 1 to 500.
2 . The particle of claim 1 , wherein R3 is alkoxy.
3 . The particle of claim 1 , wherein R3 is hydroxy.
4 . The particle of claim 1 , wherein R4 is C 6 to C 10 hydrocarbyl.
6 . The particle of claim 1 , wherein the sum of m+n is greater than 12.
7 . The particle of claim 1 , wherein m is greater than n.
8 . The particle of claim 1 having a mean particle diameter of from 0.2 to 0.35 microns.
9 . The particle of claim 1 having a mean particle diameter of less than 0.2 microns.
10 . The particle of claim 1 , wherein the titanium dioxide is treated with at least one coating material prior or subsequent to treatment with the polysiloxane.
11 . The particle of claim 10 , wherein the coating material is selected from the group consisting of aluminum oxide, silicon dioxide, zirconium oxide, inorganic phosphates, acid soluble titanium dioxide, alkanolamines, and polyalcohols.
12 . A process to prepare the particle of claim 1 , wherein the polysiloxane is added to the titanium dioxide in a mixing device.
13 . The process of claim 12 , wherein the polysiloxane is added as an aqueous emulsion.