Preparation of organic additive-treated, pyrogenic silica-encapsulated titanium dioxide particles

Abstract

One aspect of the invention is to provide a composition comprising a titanium dioxide particle having on the surface of said particle a substantially encapsulating layer comprising a pyrogenically-deposited metal oxide; said substantially encapsulating layer having on its surface at least one organic surface treatment material selected from an organo-silane, an organo-siloxane, a fluoro-silane, an organo-phosphonate, an organo-acid phosphate, an organo-pyrophosphate, an organo-polyphosphate, an organo-metaphosphate, an organo-phosphinate, an organo-sulfonic compound, a hydrocarbon-based carboxylic acid, an associated ester of a hydrocarbon-based carboxylic acid, a derivative of a hydrocarbon-based carboxylic acid, a hydrocarbon-based amide, a low molecular weight hydrocarbon wax, a low molecular weight polyolefin, a co-polymer of a low molecular weight polyolefin, a hydrocarbon-based polyol, a derivative of a hydrocarbon-based polyol, an alkanolamine, a derivative of an alkanolamine, an organic dispersing agent, or a mixture thereof. Another aspect of the invention is to provide processes for producing said composition.

1 . A composition comprising a titanium dioxide particle having on the surface of said particle a substantially encapsulating layer comprising a pyrogenically-deposited metal oxide; said substantially encapsulating layer having on its surface at least one organic surface treatment material selected from an organo-silane, an organo-siloxane, a fluoro-silane, an organo-phosphonate, an organo-acid phosphate, an organo-pyrophosphate, an organo-polyphosphate, an organo-metaphosphate, an organo-phosphinate, an organo-sulfonic compound, a hydrocarbon-based carboxylic acid, an associated ester of a hydrocarbon-based carboxylic acid, a derivative of a hydrocarbon-based carboxylic acid, a hydrocarbon-based amide, a low molecular weight hydrocarbon wax, a low molecular weight polyolefin, a co-polymer of a low molecular weight polyolefin, a hydrocarbon-based polyol, a derivative of a hydrocarbon-based polyol, an alkanolamine, a derivative of an alkanolamine, an organic dispersing agent, or a mixture thereof. 
     
     
         2 . The composition of  claim 1 , wherein the at least one organic surface treatment material is an organo-silane having the formula:
   R 5   x SiR 6   4-x      wherein   R 5  is a nonhydrolyzable alkyl, cycloalkyl, aryl, or aralkyl group having at least 1 to about 20 carbon atoms;   R 6  is a hydrolyzable alkoxy, halogen, acetoxy, or hydroxy group; and   x=1 to 3.   
     
     
         3 . The composition of  claim 2 , wherein the organo-silane is octyltriethoxysilane. 
     
     
         4 . The composition of  claim 1 , wherein the at least one organic surface treatment material is trimethylolpropane. 
     
     
         5 . The composition of  claim 1 , wherein the pyrogenically-deposited metal oxide is selected from silica, alumina, zirconia, phosphoria, boria, or mixtures thereof. 
     
     
         6 . The composition of  claim 5 , wherein the pyrogenically-deposited metal oxide is silica. 
     
     
         7 . The composition of  claim 1 , wherein the at least one organic surface treatment material is present in a range of from about 0.05 to about 5 wt %. 
     
     
         8 . The composition of  claim 7 , wherein the at least one organic surface treatment material is present in a range of from about 0.1 to about 1.5 wt %. 
     
     
         9 . The composition of  claim 1 , wherein the at least one organic surface treatment material is an organic dispersing agent selected from citric acid, polyacrylic acid, polymethacrylic acid, or polymeric organic dispersing agent having anionic, cationic, zwitterionic, or non-ionic functionality derived from a linear, comb, star, brush, or dendrimer polymer chain and pendant substituent morphology. 
     
     
         10 . The composition of  claim 9 , wherein the organic dispersing agent is present in a range of from about 0.01 to about 1.0 wt %. 
     
     
         11 . A pigment comprising a composition of  claim 1 . 
     
     
         12 . A thermoplastic resin comprising a titanium dioxide pigment having on the surface of said pigment a substantially encapsulating layer comprising a pyrogenic silica; wherein the pyrogenic silica-encapsulated titanium dioxide is treated with an organo-silane having the formula:
   R 5 SiR 6   3      wherein R 5  is a nonhydrolyzable alkyl, cycloalkyl, aryl, or aralkyl group having at least 1 to 18 carbon atoms;   R 6  is a hydrolyzable alkoxy, halogen, acetoxy, or hydroxy group.   
       and the thermoplastic resin is polyethylene. 
     
     
         13 . (canceled) 
     
     
         14 . (canceled) 
     
     
         15 . The thermoplastic resin of  claim 2 , wherein the polyethylene is an ultra low density polyethylene, a very low density polyethylene, a linear low density polyethylene, a low density polyethylene, a medium density polyethylene, a high density polyethylene, a high molecular weight high density polyethylene, an ultra high molecular weight high density polyethylene, an ethylene/vinyl acetate co-polymer, an ethylene/methacrylic acid co-polymer, or a blend thereof. 
     
     
         16 . The thermoplastic resin of  claim 2 , wherein the polypropylene is a homopolymer, a copolymer, a compounded olefin, an in situ thermoplastic olefin, or a blend thereof. 
     
     
         17 - 34 . (canceled) 
     
     
         35 . The thermoplastic resin of  claim 12 , wherein the thermoplastic resin is pigmented by an extrusion application, a molded article application, or a post-article forming coating application. 
     
     
         36 . The thermoplastic resin of  claim 35 , wherein extrusion is performed by cast film extrusion, blown film extrusion, slit film extrusion, sheet and profile extrusion, fiber and filament extrusion, or wire coating extrusion. 
     
     
         37 . The thermoplastic resin of  claim 35 , wherein the molded article application is performed by injection molding, blow molding, or rotational molding. 
     
     
         38 . The thermoplastic resin of  claim 35 , wherein the post-article forming coating application is performed by powder coating, roll-on coating, brush-on coating, trowel-on coating, or spray-on coating. 
     
     
         39 - 48 . (canceled) 
     
     
         49 . An extruder article comprising the thermoplastic resin of  claim 12 . 
     
     
         50 . A molded article comprising the thermoplastic resin of  claim 12 . 
     
     
         51 . A cast film comprising the thermoplastic resin of  claim 12 . 
     
     
         52 . A blown film comprising the thermoplastic resin of  claim 12 . 
     
     
         53 . A slit film comprising the thermoplastic resin of  claim 12 . 
     
     
         54 . An extruded sheet comprising the thermoplastic resin of  claim 12 . 
     
     
         55 . An extruded profile comprising the thermoplastic resin of  claim 12 . 
     
     
         56 . An extruded filament comprising the thermoplastic resin of  claim 12 . 
     
     
         57 . An extruded fiber comprising the thermoplastic resin of  claim 12 . 
     
     
         58 . A wire coating comprising the thermoplastic resin of  claim 12 . 
     
     
         59 . An injection molded article comprising the thermoplastic resin of  claim 12 . 
     
     
         60 . A blow molded article comprising the thermoplastic resin of  claim 12 . 
     
     
         61 . A rotational molded article comprising the thermoplastic resin of  claim 12 . 
     
     
         62 . A post-article formed coating comprising the thermoplastic resin of  claim 12 .