Abrasive silica compositions and dentifrice compositions prepared therefrom
AssigneeW. R. Grace & Co.-Conn.
InventorsMichael Bruce Thomas, Michael Vance Ernest, Sandra Joan Kempske
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Abstract
Silica compositions for abrasive systems in dentifrice formulations are disclosed. The silica abrasive system comprises (a) silica gels having a median particle size below 7 microns, a pH of from about 6 to about 11 and powder RDA's of from 100 to about 200 and (b) silica gels or precipitates having a median particle size of 7 microns or greater and powder RDA's of from 50 to about 180. Silica (a) is preferably prepared by contacting a hydrous silica gel with an alkaline medium. Dentifrice compositions comprising the abrasive system has an RDA of 150 or less and PCR's of at least 80 and up to about 150, and an REA of less than about 30 (as measured on the IU scale).
Claims10
A silica abrasive composition comprising
- (a) silica gel (i) having a median particle size below about 7 microns, (ii) a pH of from about 6 to about 11, and (iii) a hardness defined by a powder RDA of 100 to 200, and a PCR of 100 to about 150 when said silica (a) is formulated by itself into a dentifrice paste;
- and
- (b) silica gel or precipitated silica having a median particle size of about 7 microns or greater and having a hardness defined by a powder RDA of about 50 to 180, and a PCR of about 80 to 105 when said silica (b) is formulated in a dentifrice paste;
- further wherein the weight ratio of (b) to (a) is at least 1:1.
Dependencies are inferred from the claim text.