Surface modified pigments

Abstract

.Iadd.Finely divided particulate inorganic pigment is surface modified with from about 1% to about 15% of an amino organosilane, particularly gamma-aminopropyltriethoxy silane. Thermosetting resins incorporating such modified inorganic pigments exhibit improved physical properties.

I claim: 
     
       1. A .Iadd.filler comprising a .Iaddend.finely divided particulate inorganic pigment surface .Iadd.selected from the group consisting of synthetic silicas, silicates, metal oxides, calcium carbonates, zinc sulfides, and carbon blacks, said pigment surface having been .Iaddend.modified .Iadd.by treatment .Iaddend.with from about 1% to 15%, based on the weight of the dry pigment, of an amino organosilane of the formula ##STR2## wherein R 1  is selected from the group consisting of hydrogen, alkyl, aryl, cycloalkyl, and alkylaryl, R 2  is selected from the group consisting of hydrogen, alkyl, aryl, cycloalkyl and alkylaryl, R 3  is selected from the group consisting of hydrogen, lower alkyl, aryl, lower alkylaryl and lower arylalkyl, R 4  is selected from the group consisting of hydrogen, lower alkyl, aryl, lower alkylaryl and lower arylalkyl, R 5  is selected from the group consisting of hydrogen, lower alkyl, aryl, lower alkylaryl, and lower arylalkyl, X is selected from the group consisting of alkylene, arylene, alkylarylene, arylalkylene, cycloalkylene containing secondary amino nitrogen, and cycloalkylene containing tertiary amino nitrogen.Iadd., the modification of said pigment surface by said organosilane comprising spray drying slurries of said pigment having one or more of the amino organosilanes dispersed therein. .Iaddend. .[. 
     
     
       2.  A compound as in claim 1 wherein the finely divided particulate filler is selected from the group consisting of synthetic silicas, silicates, metal oxides, calcium carbonates, zinc sulfides, and carbon blacks..]. 
     
     
       3. A compound as in claim 1 wherein the amino organosilane is gamma aminopropyltriethoxysilane. 
     
     
       4. A compound as in claim 1 wherein the amino organosilane is a diamino functional silane. 
     
     
       5. Finely divided particulate hydrated silica, surface modified with from about 1% to 15% by weight based upon the weight of the silica of gamma aminopropyltriethoxysilane. 
     
     
       6. Finely divided particulate sodium alumino silicate pigment, surface modified with from about 1% to 15% by weight, based upon the weight of the pigment, of gamma aminopropyltriethoxysilane. 
     
     
       7. Finely divided particulate carbon black, surface modified with from about 1%to 15% by weight, based upon the weight of the carbon black, of gamma aminopropyltriethoxysilane. 
     
     
       8. Finely divided particulate kaolin clay, surface modified with from about 1% to 15% by weight, based upon the weight of the kaolin clay, of gamma aminopropyltriethoxysilane. .Iadd. 9. A filler comprising a finely divided particulate inorganic pigment surface selected from the group consisting of synthetic silicas, silicates, metal oxides, calcium carbonates, zinc sulfides, and carbon blacks, said pigment surface having been modified by treatment with from about 1% to 15%, based on the weight of the dry pigment, of an amino organosilane of the formula   H.sub.2 N--R--Si(Or').sub.3     wherein R is selected from the group consisting of phenylene lower alkyl substituted phenylene, lower alkoxy substituted phenylene, and lower alkylene, R' is a monovalent hydrocarbon group free of aliphatic unsaturation selected from the group consisting of lower alkyl, aryl, lower alkaryl and lower aralkyl, wherein R' can represent the same or different groups. .Iaddend.