THERMAL RESISTANT TITANIUM DIOXIDE PARTICLES AND THE FORMATION OF COOL ARTICLES
The present disclosure relates to titanium dioxide particles designed to enhance reflection of both IR and visible wavelengths, or energy, and their use in forming cool, fully opaque polymeric articles prepared by melt processible resin. Such articles, made from melt processible thermoplastic and/or thermoset resin have enhanced outdoor utility because they inhibit damage caused by the sun as a result of the article including titanium dioxide particles of the present invention exhibiting low photo-activity properties.
1 . Thermal resistant, low photo-activity, titanium dioxide particles comprising:
a) a TiO2 particle comprising a surface having a median particle size between 0.30 μm and 0.38 μm;
b) a silica coating;
c) an alumina coating having an interior and exterior surface; and
d) an organic coating,
wherein the silica coating is located between the surface of the TiO2 particle and the interior surface of the alumina coating and the organic coating is located on the exterior surface of the alumina coating.
2 . The composition of claim 1 wherein the TiO2 particle further comprises a rutile crystalline form.
3 . The composition of claim 1 wherein the organic coating is selected from the group of organic compounds selected from the group consisting of an organosiloxane, organosilane, alkyl carboxylic acid, alkyl sulfonate, organophosphate, orgaonophosphonate, and a combination thereof.
4 . The composition of claim 3 wherein the organic coating is polydimethyl siloxane.
5 . The composition of claim 1 , wherein the median particle size is in the range of 0.32 and 0.36.
6 . The composition of claim 1 , wherein the median particle size is in the range of 0.32 μm and 0.35 μm.
7 . The composition of claim 1 wherein the silica coating is in the range of 1.0 to 5.0 wt. % of the total particle weight.