Precipitated silica product, dentifrices containing same, and processes
View Patent ↗Precipitated silica comprising porous silica particles having a cumulative surface area for all pores having diameters greater than 500 Å of less than 8 m 2 /g, as measured by mercury intrusion, and a percentage cetylpyridinium chloride (% CPC) Compatibility of greater than about 55%. The precipitated silica product is especially well-adapted for use in dentifrices containing cetylpyridinium chloride, which do not attach to the low surface area silica product in a meaningful level and thus remain available for antimicrobial action. Processes for making the silica product are also provided.
1. Precipitated silica comprising silica product particles having a porous surface, the silica particles having a cumulative surface area for all pores having diameters greater than about 500 Å of less than 8 m 2 /g, as measured by mercury intrusion, a BET specific surface area of less than approximately 30 square meters per gram, and a percentage cetylpyridinium chloride (% CPC) Compatibility of greater than about 55%.
2. A silica product according to claim 1 , wherein the silica particles have a percentage cetylpyridinium chloride (% CPC) Compatibility of greater than approximately 60%.
3. A silica product according to claim 1 , wherein the silica particles have a % CPC Compatibility of greater than approximately 70%.
4. A silica product according to claim 1 , wherein the silica particles have a % CPC Compatibility of greater than approximately 80%.
5. A silica product according to claim 1 , wherein the silica particles have a median diameter of 1 to 20 micrometers.
6. A silica product according to claim 1 , wherein the silica particles have a % CPC Compatibility value of approximately 55% to 95%.
7. A silica product according to claim 1 , wherein the silica particles comprise silica aggregates or agglomerates individually comprising unitary clusters of a plurality of silica primary particles.
8. A silica product according to claim 1 , the silica particles having a cumulative surface area for all pores having diameters greater than about 500 Å of less than 7 m 2 /g, as measured by mercury intrusion.
9. Dentifrice, comprising:
a silica product comprising silica particles having a porous surface, the silica particles having a cumulative surface area for all pores having diameters greater than about 500 Å of less than 8 m 2 /g, as measured by mercury intrusion, a BET specific surface area of less than approximately 30 square meters per gram, and a percentage cetylpyridinium chloride (% CPC) Compatibility of greater than about 55%.
10. Dentifrice according to claim 9 , wherein the silica particles have a percentage cetylpyridinium chloride (% CPC) Compatibility of greater than approximately 60%.
11. Dentifrice according to claim 9 , wherein the silica particles provide an increased flavor compatibility as compared to a dentifrice containing corresponding silica particles without said cumulative surface area and % CPC Compatibility.
12. Dentifrice according to claim 9 , wherein the silica particles have a percentage cetylpyridinium chloride (% CPC) Compatibility of greater than approximately 70%.
13. Dentifrice according to claim 9 , wherein the silica particles have a percentage cetylpyridinium chloride (% CPC) Compatibility of greater than approximately 80%.
14. Dentifrice according to claim 9 , wherein the silica wherein the silica particles have a % CPC Compatibility value of approximately 55% to 95%.
15. Dentifrice according to claim 9 , wherein the silica particles comprise aggregates or agglomerates individually comprised of clusters of a plurality of silica primary particles.
16. Dentifrice according to claim 9 , further including an effective amount of at least one flavorant compatible with CPC.
17. Dentifrice according to claim 9 , further including an effective amount of an anticaries compound comprising a fluoride ion source.
18. Dentifrice according to claim 9 , further including an effective amount of antimicrobial agent.
19. Dentifrice according to claim 9 , the silica particles having a cumulative surface area for all pores having diameters greater than about 500 A of less than 7 m 2 /g, as measured by mercury intrusion.
20. Dentifrice, comprising:
a) antibacterial effective amount of cetylpyridinium chloride;
b) precipitated silica product comprising silica particles having a porous surface, the silica particles having a cumulative surface area for all pores having diameters greater than about 500 Å of less than 8 m 2 /g, as measured by mercury intrusion, a BET specific surface area of less than approximately 30 square meters per gram, and a percentage cetylpyridinium chloride (% CPC) Compatibility of greater than about 55%.
21. Process for making precipitated silica product, comprising: a)
providing amorphous silica substrate particles having a median diameter of 1 to 100 micrometers;
b) depositing active silica onto surfaces of the silica substrate particles by acidulation of an alkali metal silicate in an aqueous medium, in which the substrate particles are dispersed, in an amount effective to provide a slurry of silica particles having a porous surface, the silica particles having a cumulative surface area for all pores having diameters greater than about 500 A of less than 8 m 2 /g, as measured by mercury intrusion, and a percentage cetylpyridinium chloride (% CPC) Compatibility of greater than about 55%.
22. The process of claim 21 , further comprising dewatering and drying the silica particles to a flowable finely divided particulate form.
23. The process of claim 21 , wherein the providing of the silica particles comprises slurrying a dry flowable particulate form of the silica particles in an aqueous solution.
24. The process of claim 21 , wherein the providing of the silica particles comprises forming the silica particles in situ by acidulation of an alkali metal silicate in an aqueous medium without drying below 20% water content before initiating step “b” thereof.
25. The process of claim 21 , wherein the providing of the silica particles comprises providing silica aggregates or agglomerates individually comprising unitary clusters of a plurality of the amorphous silica primary particles.
26. The process of claim 21 , wherein the silica particles have a % CPC Compatibility of greater than approximately 60%.
27. The process of claim 21 , wherein the silica particles have a % CPC Compatibility of greater than approximately 70%.
28. The process of claim 21 , wherein the silica particles have a % CPC Compatibility of greater than approximately 80%.
29. The process of claim 21 , wherein the silica particles have a % CPC Compatibility within the range of about 55% to about 90%.
30. The product of the process of claim 21 .