DISPERSION OF FINE POROUS OXIDE INORGANIC OXIDE PARTICLES AND PROCESSES FOR PREPARING SAME

摘要

1. A dispersion comprising porous inorganic oxide particles, wherein the particles have a) a median particle size in the range of 0.05 to about 3 microns; and b) porosity such that when an aqueous dispersion of the particles is dried at least about 0.5 cm<3>/g of pore volume as measured by BJH nitrogen porosimetry is from pores having a pore size of 60 nm (600 angstrom ) or smaller. 2. A dispersion of Claim 1 wherein the inorganic oxide particles comprise silica particles. 3. A dispersion of Claim 2 wherein the silica particles comprise precipitated silica or silica gel. 4. A dispersion of Claim 1 wherein the inorganic particles have a median particle size in the range of 0.05 to about 1 micron. 5. A dispersion of Claim 3 wherein the silica particles have a porosity after drying in which at least about 0.7 cm<3>/g of the pore volume is from pores having a pore size of 60 nm (600 angstrom ) or less. 6. A dispersion of Claim 5 wherein the silica particles comprise silica gel. 7. A dispersion of Claim 1 wherein the porous particles have a viscosity derived pore volume in the range of 0.5 to about 1.5 cm<3>/g. 8. A dispersion of Claim 1 wherein the porous particles have a viscosity derived pore volume of about 1.0 to about 1.5 c/g. 9. A dispersion of Claim 8 wherein the median particle size is about 0.5 micron or smaller, the solids content is about 20 to about 25 weight % and the dispersion comprises at least 90% glycol. 10. A dispersion of Claim 9 wherein the inorganic oxide is silica gel. 11. A dispersion of Claim 7 wherein the porous particles comprise precipitated silica or silica gel. 12. A dispersion of Claim 8 wherein the porous particles comprise precipitated silica or silica gel. 13. A dispersion of Claim 1 comprising 1-30% by weight inorganic oxide particles. 14. A dispersion of Claim 11 wherein the particles comprise silica gel and the particles have a porosity after drying in which at least about 0.7 cm<3>/g of the pore volume is from pores having a pore size less than of 60 nm (600 angstrom ). 15. A dispersion of Claim 11 wherein the porous particles have a viscosity derived pore volume in the range of 0.5 to about 1.5 cm<3>/g. 16. A dispersion of Claim 1 wherein the porous particles have a viscosity derived pore volume of about 1.0 to about 1.5 cm<3>/g. 17. A dispersion of Claim 1 prepared by a process comprising i) forming a slurry of inorganic oxide particles; ii) milling the slurry of particles; iii) creating a supernatant phase and a settled phase from the resulting milled dispersion wherein the supernatant phase comprises porous inorganic oxide particles which have a median particle size in the range of 0.1 to about one micron; and iv) removing the supernatant phase as a dispersion of particles. 18. A dispersion of Claim 17 wherein the inorganic oxide particles in i) comprises silica gel or precipitated silica. 19. A method of preparing a dispersion of particles comprising (a) forming a slurry of inorganic oxide particles; (b) milling the slurry of particles; (c) creating a supernatant phase and a settled phase from the resulting milled slurry; and (d) removing the supernatant phase or redispersing the settled phase as a final product wherein when said product has a porosity after being dried in which at least 0.5 cm<3>/g of pore volume is from pores having a pore size of 60 nm (600 angstrom ) or smaller. 20. A method of Claim 19 wherein the inorganic oxide particles in (a) comprise silica gel or precipitated silica dioxide. 21. A method of Claim 19 wherein the inorganic oxide particles in (a) comprise silica gel and the particles have a porosity in which at least about 0.7 cm<3>/g of the pore volume is from pores having a size of 30 nm (300 angstrom ). or smaller. 22. A method of Claim 19 wherein the final product of (d) has a viscosity derived pore volume in the range of 0.5 to about 1.5 cm<3>/g. 23. A method of Claim 19 wherein the slurry in (a) is an aqueous medium and final product of (d) is distilled with glycol to produce a dispersion comprising at least 90% glycol. 24. A method of Claim 23 wherein the glycol is ethylene glycol.