Novel precipitated siliceous products and methods for their use and production

• US 4,336,245 A
• Filed: 05/11/1979
• Issued: 06/22/1982
• Est. Priority Date: 03/12/1975
• Status: Expired due to Term

• Current Assignee: JM Huber Corporation
• Original Assignee: JM Huber Corporation
• Inventors: Wason, Satish K.
• Primary Examiner(s): Rose, Shep K.
• Application Number:
  US06/039,061
• Time in Patent Office: 1,138 Days
• Field of Search: 424/49-58, 423/339, 106/288 B
• US Class Current: 424/49
• CPC Class Codes: A61K 47/02 Inorganic compounds
• CPC Class Codes: A61K 8/25 Silicon; Compounds thereof
• CPC Class Codes: A61K 9/0014 Skin, i.e. galenical aspects of topical compositions non-active ingredients are additionally classified in A61K47/00; A61K9/0009, A61K9/0021, A61K9/7015, A61K9/7023 take precedence; cosmetic preparations A61K8/00, A61Q; preparations for wound dressings or bandages A61L26/00
• CPC Class Codes: A61Q 11/00 Preparations for care of the teeth, of the oral cavity or of dentures; Dentifrices, e.g. toothpastes; Mouth rinses
• CPC Class Codes: C01B 33/193 of aqueous solutions of silicates
• CPC Class Codes: C01P 2002/02 Amorphous compounds
• CPC Class Codes: C01P 2004/02 obtained by optical microscopy
• CPC Class Codes: C01P 2004/03 obtained by SEM
• CPC Class Codes: C01P 2004/62 Submicrometer sized, i.e. from 0.1-1 micrometer
• CPC Class Codes: C01P 2004/80 Particles consisting of a mixture of two or more inorganic phases
• CPC Class Codes: C01P 2006/12 Surface area
• CPC Class Codes: C01P 2006/14 Pore volume
• CPC Class Codes: C01P 2006/16 Pore diameter
• CPC Class Codes: C01P 2006/19 Oil-absorption capacity, e.g. DBP values
• CPC Class Codes: C01P 2006/60 Optical properties, e.g. expressed in CIELAB-values
• CPC Class Codes: C01P 2006/80 Compositional purity
• CPC Class Codes: C01P 2006/82 water content
• CPC Class Codes: C01P 2006/90 Other properties not specified above
• CPC Class Codes: C08K 3/36 Silica
• CPC Class Codes: C08L 21/00 Compositions of unspecified rubbers
• CPC Class Codes: C09C 1/28 : Compounds of silicon C09C1/0009, C09C1/0015, C09C1/0078 take precedence
• CPC Class Codes: D21H 17/68 : siliceous, e.g. clays

Abstract

A method for producing a precipitated silicon dioxide having a new combination of physical and chemical properties is disclosed. The pigments are produced by acidulating a solution of an alkali metal silicate with an acid under controlled precipitation conditions. The aqueous reaction medium comprising the precipitated silica is then post-conditioned by introducing a second silicate solution into the reaction vessel and thereafter adding additional acid to react with the said second silicate solution. By varying the amount of the silicate employed in the post-conditioning step, a product is obtained which has a unique combination of physical and chemical properties including reduced wet cake moisture content, high surface areas and oil absorptions, improved surface activity, friability, wetting characteristics, and the like. The product has particular utility for use as a rubber reinforcing agent because of its increased surface activity and oil absorption, etc. The product, however, may be used in paints, paper, detergents, dentifrice compositions, molecular sieves, and polymeric compositions. An unexpected discovery of the invention involves the production of a rubber reinforcing silica which has a decreased wet cake moisture content. In one particularly advantageous embodiment, an adduct material, such as aluminum, is added to control the refractive index and surface area of the product.

Claims

1. A dentifrice including, as a thickening and polishing agent, a finely divided, amorphous, precipitated silicon dioxide having the combined properties of a structure index of less than 505 and an oil absorption of greater than 190 cc/100 grams;

said silicon dioxide comprising not less than 90% SiO₂ and including a metal cation incorporated therein, said metal cation serving to control the refractive index of said silicon dioxide such that said refractive index is not less than 1.45 and serving to control the surface area of said silicon dioxide such that said surface area is not less than 153 m² /gram, said metal cation being selected from the group consisting of aluminum, magnesium, zinc, and calcium.

4. A dentifrice composition according to claim 1 in a form of a toothpaste which comprises said thickening and polishing agent together with humectants, binders, preservatives, detergents, flavoring agents, sweeteners and therapeutic agents.

5. A toothpaste according to claim 4 wherein said humectant is selected from the group consisting of glycerine, sorbitol and mixtures thereof, and wherein said binder is selected from the group consisting of seaweed colloids, synthetic derivatives of cellulose, gums and mixtures thereof.

2. A dentifrice including, as a thickening and polishing agent, a finely divided, amorphous, precipitated silicon dioxide having a wet cake moisture content of from between about 79.8 to 83.5%;

a structure index of from between about 359 to 505;

an oil absorption of from between about 190 to 202 cc/100 grams;

a void volume of from between about 3.55 to 4.14 cc Hg/gram SiO₂ ;

a BET surface area of from between about 120 to 153 m² /gram; and

a percent friability of up to about 98%.

6. A dentifrice composition according to claim 2 in a form of a toothpaste which comprises said thickening and polishing agent together with humectants, binders, preservatives, detergents, flavoring agents, sweeteners and therapeutic agents.

7. A toothpaste according to claim 6 wherein said humectant is selected from the group consisting of glycerine, sorbitol and mixtures thereof, and wherein said binder is selected from the group consiting of seaweed colloids, synthetic derivatives of cellulose, gums and mixtures thereof.

3. A dentifrice including, as a thickening and polishing agent, a finely divided, amorphous, precipitated silicon dioxide having a wet cake moisture content of from between about 77.9 to 83.2%;

a structure index of from between about 365 to 495;

an oil absorption of from between about 193 to 212 cc/100 grams;

a void volume of from between about 3.19 to 4.40 cc Hg/gram SiO₂ ;

a BET surface area of from between about 153 to 220 m² /gram; and

a percent friability of up to about 93%;

said silicon dioxide comprising at least 90% SiO₂ and having incorporated therewith a metal cation selected from the group consisting of aluminum, magnesium, zinc, and calcium to thereby control the surface area thereof and to increase the refractive index thereof to a value of at least 1.45.

8. A dentifrice composition according to claim 3 in a form of a toothpaste which comprises said thickening and polishing agent together with humectants, binders, preservatives, detergents, flavoring agents, sweeteners and therapeutic agents.

9. A toothpaste according to claim 8 wherein said humectant is selected from the group consisting of glycerine, sorbitol and mixtures thereof, and wherein said binder is selected from the group consisting of seaweed colloids, synthetic derivatives of cellulose, gums and mixtures thereof.

10. A clear gel toothpaste composition containing humectants and binders in the liquid phase, and thickening and polishing agents, said composition including, as a thickening and polishing agent, a finely divided, amorphous, precipitated silicon dioxide having the combined properties of a structure index of less than 505 and an oil absorption of greater than 190 cc/100 grams;

said silicon dioxide comprising not less than 90% SiO₂ and including a metal cation incorporated therein, said metal cation serving to control the refractive index of said silicon dioxide such that said refractive index is not less than 1.45 and serving to control the surface area of said silicon dioxide such that said surface area is not less than 153 m² /gram, said metal cation being selected from the group consisting of aluminum, magnesium, zinc, and calcium;

wherein the refractive index of said liquid phase is substantially the same as said silicon dioxide.

11. A clear gel toothpaste composition containing humectants and binders in the liquid phase, and thickening and polishing agents, said composition including, as a thickening and polishing agent, a finely divided, amorphous, precipitated silicon dioxide having a wet cake moisture content of from between about 79.8 to 83.5%;

a structure index of from between about 359 to 505;

an oil absorption of from between about 190 to 202 cc/100 grams;

a void volume of from between about 3.55 to 4.14 cc Hg/gram SiO₂ ;

a BET surface area of from between about 120 to 153 m² /gram; and

a percent friability of up to about 98%;

wherein the refractive index of said liquid phase is substantially the same as said silicon dioxide.

12. A clear get toothpaste composition containing humectants and binders in the liquid phase, and thickening and polishing agents, said composition including, as a thickening and polishing agent, a finely divided, amorphous, precipitated silicon dioxide having a wet cake moisture content of from between about 77.9 to 83.2%;

a structure index of from between about 365 to 495;

an oil absorption of from between about 193 to 212 cc/100 grams;

a void volume of from between about 3.19 to 4.40 cc Hg/gram SiO₂ ;

a BET surface area of from between about 153 to 220 m² /gram; and

a percent friability of up to about 93%;

said silicon dioxide comprising at least 90% SiO₂ and having incorporated therewith a metal cation selected from the group consisting of aluminum, magnesium, zinc, and calcium to thereby control the surface area thereof and to increase the refractive index thereof to a value of at least 1.45;

wherein the refractive index of said liquid phase is substantially the same as said silicon dioxide.