| 摘要 |
<p>A coated inorganic oxide pigment, comprising: a titanium dioxide base pigment; a porous inorganic coating formed on said base pigment in situ in an aqueous slurry at a temperature in the range of from about 400 C to about 900 C, wherein said porous inorganic coating consists of silica, is formed on said base pigment at a pH in the range of from about 3 to about 7 and in an amount in the range of from about 5% to about 14% by weight, based on the weight of said base pigment; and a dense inorganic coating formed on said base pigment in situ in an aqueous slurry at a temperature in the range of from about 400 C to about 900 C, wherein said dense inorganic coating consists of alumina and is formed on said base pigment at a pH in the range of from about 4 to about 7 and in an amount in the range of from about 2% to about 14% by weight, based on the weight of said base pigment; an additional porous inorganic coating that consists of alumina and is formed on said base pigment at a pH in the range of from about 8 to about 11 and in an amount in the range of from about 2% to about 10% by weight, based on the weight of said base pigment; an additional dense inorganic coating that consists of alumina and is formed on said base pigment at a pH in the range of from about 4 to about 7 and in an amount in the range of from about 3% to about 9% by weight, based on the weight of said base pigment; an additional dense inorganic coating that consists of silica and is formed on said base pigment at a pH in the range of from about 8 to about 11 and in an amount in the range of from about 5% to about 10% by weight, based on the weight of said base pigment; and wherein one of said dense alumina coatings is formed directly on said base pigment, said porous silica coating is formed on said base pigment on top of said dense alumina coating, the other of said dense alumina coatings is formed on said base pigment on top of said porous silica coating, said dense silica coating is formed on said base pigment on top of said dense alumina coating, and said porous alumina coating is formed on said base pigment on top of said dense silica coating.</p> |
