Rhone-poulenc Chimie

Rohne-poulenc Chimie

Jacques Persello

Thierry Chopin

Jean-Yves Chane-Ching

Claude Ceintrey

Francois Parmentier

Michel Sutter

Precipitated silica particulates having a BET specific surface ranging from 20 to 300 m.sup.2 /g, a CTAB specific surface ranging from 10 to 200 m.sup.2 /g, an oil uptake (DBP) ranging from 80 to 400 cm.sup.3 /100 g, a pore volume ranging from 1 to 10 cm.sup.3 /g and a mean pore diameter ranging from 10 to 50 nm, well adapted for such applications as the coating of paper and catalysis, are prepared by (a) simultaneously introducing a silicate and an acid into a dispersion of colloidal silica, thereby providing a silica suspension, (b) next decreasing the pH of such suspension to a value ranging from 3 to 7, and (c) then separating the silica particulates from the final suspension and drying them.

Precipitated silica particulates having controlled porosity

In a first embodiment of the invention, a colloidal dispersion of a cerium compound is characterised in that it has a pH of at least 4 and a conductivity of at most 5 mS/cm. In a second embodiment, the colloidal dispersion is characterised in that it has a pH of more than 5. In a third embodiment, the colloidal dispersion is characterised in that the colloids have a carbon content such that the carbon/cerium mole ratio is at Least 0.01 and in that the pH is greater than 5. A process for the preparation of these dispersions is characterised in that a first colloidal dispersion is used as a starting material, with a pH which is lower than the pH of the dispersion which is to be prepared, and the pH of the first dispersion is raised while reducing the ionic strength. For the third embodiment, an organic acid is added to the starting dispersion.

High pH colloidal dispersion of a cerium compound, and a process for its

Novel silica particulates adopted for formulation into dentifrice compositions have a unique surface chemistry as to be at least 50% compatible with zinc values, and have a number of OH functions, expressed as OH/nm.sup.2, of at most 15 and a zero charge point (PZC) of from 3 to 6.5.

Method of preparing dentifrice-compatible silica particulates

Zinc-compatible silica particulates, useful for the formulation of a wide variety of improved dentifrice compositions, have an effective compatibilizing amount of zinc values chemically bonded to surface area sites of the particles.

Zinc/dentifrice-compatible silica particulates

Novel silica particulates especially adapted for formulation to dentifrice compositions exhibit unique physical and chemical properties. In one embodiment, silica particulates have a unique surface chemistry as to be at least 50% compatible with zinc values, and have a number of OH functions, expressed as OH/nm.sup.2, of at most 15 and a zero charge point (PZC) of from 3 to 6.5. In a second embodiment, particulates have a surface chemistry as to be at least 65%, and preferably at least 90% compatible with guanidine values, notably chlorhexidine, and acidity function thereof, Ho, of at least 3.3. In a third embodiment, silica particulates are compatible with organic amines, and have a pH, in aqueous suspension, which varies according to the equations pH.ltoreq.7.5-0.7 log(C) and pH.gtoreq.5.0-0.5 log(C) and which also varies as a function of the electrical conductivity thereof, according to the equations pH.ltoreq.8.5-0.4 log(D) and pH.gtoreq.7.0-0.6 log(D) wherein (C) represents the weight concentration of said silica suspension, expressed % SiO.sub.2 and (D) represents the electrical conductivity of such aqueous silica suspension expressed in microsiemens.multidot.cm.sup.-. In a fourth embodiment, novel silica particulates are compatible with such metal cations as zinc, tin, strontium, and the like, as well as with the fluorides, and have a unique surface chemistry such that the number of OH.sup.- functions thereof, expressed in OH.sup.- /nm.sup.2, is equal to or less than 10, and also have a zero charge point (ZCP) ranging from 3 to 6.5 and a pH, in aqueous suspension, which varies as a function of the electrical conductivity thereof according to the equation pH=b-a log (D) in which a is a constant equal to or less than 0.6; b is a constant equal to or less than 8.5; and (D) represents the electrical conductivity of such aqueous silica suspension, expressed in microsiemens.multidot.cm.sup.-.

Dentifrice-compatible silica particulates

Novel silica particulates especially adapted for formulation to dentifrice compositions exhibit unique physical and chemical properties. In one embodiment, silica particulates have a unique surface chemistry as to be at least 50% compatible with zinc values, and have a number of OH functions, expressed as OH/nm.sup.2, of at most 15 and a zero charge point (PZC) of from 3 to 6.5. In a second embodiment, particulates have a surface chemistry as to be at least 65%, and preferably at least 90% compatible with guanidine values, notably chlorhexidine, and acidity function thereof, Ho, of at least 3.3. In a third embodiment, silica particulates are compatible with organic amines, and have a pH, in aqueous suspension, which varies according to the equations pH.ltoreq.7.5-0.7 log(C) and pH.gtoreq.5.0-0.5 log(C) and which also varies as a function of the electrical conductivity thereof, according to the equations pH.ltoreq.8.5-0.4 log(D) and pH.gtoreq.7.0-0.6 log(D) wherein (C) represents the weight concentration of said silica suspension, expressed % SiO.sub.2 and (D) represents the electrical conductivity of such aqueous silica suspension expressed in microsiemens.cm.sup.-1. In a fourth embodiment, novel silica particulates are compatible with such metal cations as zinc, tin, strontium, and the like, as well as with the fluorides, and have a unique surface chemistry such that the number of OH.sup.- functions thereof, expressed in OH.sup.- /nm.sup.2, is equal to or less than 10, and also have a zero charge point (ZCP) ranging from 3 to 6.5 and a pH, in aqueous suspension, which varies as a function of the electrical conductivity thereof according to the equation pH=b-a log (D) in which a is a constant equal to or less than 0.6; b is a constant equal to or less than 8.5; and (D) represents the electrical conductivity of such aqueous silica suspension, expressed in microsiemens.cm.sup.-1.

Novel silica particulates especially adapted for formulation to dentifrice compositions exhibit unique physical and chemical properties. In one embodiment, silica particulates have a unique surface chemistry as to be at least 50% compatible with zinc values, and have a number of OH functions, expressed as OH/nm.sup.2, of at most 15 and a zero charge point (PZC) of from 3 to 6.5. In a second embodiment, particulates have a surface chemistry as to be at least 65%, and preferably at least 90% compatible with guanidine values, notably chlorhexidine, and acidity function thereof, Ho, of at least 3.3. In a third embodiment, silica particulates are compatible with organic amines, and have a pH, in aqueous suspension, which varies according to the equations pH.ltoreq.7.5-0.7 log(C) and pH.gtoreq.5.0-0.5 log(C) and which also varies as a function of the electrical conductivity thereof, according to the equations pH.ltoreq.8.5-0.4 log(D) and pH.gtoreq.7.0-0.6 log(D) wherein (C) represents the weight concentration of said silica suspension, expressed % SiO.sub.2 and (D) represents the electrical conductivity of such aqueous silica suspension expressed in microsiemens.multidot.cm.sup.-1. In a fourth embodiment, novel silica particulates are compatible with such metal cations as zinc, tin, strontium, and the like, as well as with the fluorides, and have a unique surface chemistry such that the number of OH.sup.- functions thereof, expressed in OH.sup.- /nm.sup.2, is equal to or less than 10, and also have a zero charge point (ZCP) ranging from 3 to 6.5 and a pH, in aqueous suspension, which varies as a function of the electrical conductivity thereof according to the equation pH=b-a log (D) in which a is a constant equal to or less than 0.6; b is a constant equal to or less than 8.5; and (D) represents the electrical conductivity of such aqueous silica suspension, expressed in microsiemens.multidot.cm.sup.-1.

Novel silica particulates especially adapted for formulation to dentifrice compositions exhibit unique physical and chemical properties. In one embodiment, silica particulates have a unique surface chemistry, as to be at least 50% compatible with zinc values, and have a number of OH functions, expressed as OH/nm.sup.2, of at most 15 and a zero charge point (PZC) of from 3 to 6.5. In a second embodiment, particulates have a surface chemistry as to be at least 65%, and preferably at least 90% compatible with guanidine values, notably chlorhexidine, and acidity function thereof, Ho, of at least 3.3. In a third embodiment, silica particulates are compatible with organic amines, and have a pH, in aqueous suspension, which varies according to the equations pH.ltoreq.7.5-0.7 log(C) and pH.gtoreq.5.0-0.5 log(C) and which also varies as a function of the electrical conductivity thereof, according to the equations pH.ltoreq.8.5-0.4 log(D) and pH.gtoreq.7.0-0.6 log(D) wherein (C) represents the weight concentration of said silica suspension, expressed % SiO.sub.2 and (D) represents the electrical conductivity of such aqueous silica suspension expressed in microsiemens.multidot.cm.sup.-1. In a fourth embodiment, novel silica particulates are compatible with such metal cations as zinc, tin, strontium, and the like, as well as with the fluorides, and have a unique surface chemistry such that the number of OH.sup.- functions thereof, expressed in OH.sup.- /nm.sup.2, is equal to or less than 10, and also have a zero charge point (ZCP) ranging from 3 to 6.5 and a pH, in aqueous suspension, which varies as a function of the electrical conductivity thereof according to the equation pH=b-a log (D) in which a is a constant equal to or less than 0.6; b is a constant equal to or less than 8.5; and (D) represents the electrical conductivity of such aqueous silica suspension, expressed in microsiemens.multidot.cm.sup.-1.

Process for the preparation of zinc/dentifrice-compatible silica

Novel silica particulates especially adapted for formulation to dentifrice compositions exhibit unique physical and chemical properties. In one embodiment, silica particulates have a unique surface chemistry as to be at least 50% compatible with zinc values, and have a number of OH functions, expressed as OH/nm.sup.2, of at most 15 and a zero charge point (PZC) of from 3 to 6.5. In a second embodiment, particulates have a surface chemistry as to be at least 65%, and preferably at least 90% compatible with guanidine values, notably chlorhexidine, and acidity function thereof, Ho, of at least 3.3. In a third embodiment, silica particulates are compatible with organic amines, and have a pH, in aqueous suspension, which varies according to the equations pH.ltoreq.7.5-0.7 log(C) and pH.gtoreq.5.0-0.5 log(C) and which also varies as a function of the electrical conductivity thereof, according to the equations pH.ltoreq.8.5-0.4 log(D) and pH.gtoreq.7.0-0.6 log(D) wherein (C) represents the weight concentration of said silica suspension, expressed % SiO.sub.2 and (D) represents the electrical conductivity of such aqueous silica suspension expressed in microsiemens.multidot.cm.sup.-1. In a fourth embodiment, novel silica particulates are compatible with such metal cations as zinc, tin, strontium, and the like, as well as with the fluorides, and have a unique surface chemistry such that the number of OH.sup.- functions thereof, expressed in OH.sup.- /nm.sup.2, is equal to or less than 10, and also have a zero charge point (ZCP) ranging from 3 to 6.5 and a pH, in aqueous suspension, which varies as a function of the electrical conductivity thereof according to the equation pH=b-a log (D) in which a is a constant equal to or less than 0.6; b is a constant equal to or less than 8.5; and (D) represents the electrical conductivity of such aqueous silica suspension, expressed in microsiemens.multidot.cm.sup.-1

Novel pigmentary colorants, well adapted for the production of electrostatic developer powders, are comprised of mineral core particulates, at least one mineral oxide and at least one dye, said at least one mineral oxide being deposited onto the surface area of the core particulates, and said at least one dye being absorbed onto the core particulates or onto the at least one mineral oxide and/or being at least partly physically confined within a matrix of the mineral oxide.

Core/oxide/dye pigmentary colorants

Novel Pigmentary colorants, well adapted for the production of electrostatic developer powders and dentifrices, are comprised of coprecipitated/crystallized mineral oxide particulates and at least one dye. The at least one dye is at least partly physically confined within a matrix of the mineral oxide.

Novel oxide/dye pigmentary colorants

Hydrophobic, essentially spheroidal precipitated silica particulates, well adapted as a reinforcing filler material for silicone elastomers, have a density of at least 0.15, a water wettability of at least 20% and a maximum water uptake of 5%.

Growing community of inventors

Montluel, France

Jacques Persello