The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 16, 2010
Filed:
Nov. 29, 2002
Peter W. Stanier, Sandbach, GB;
Simon R. Stebbing, Warrington, GB;
Peter W. Stanier, Sandbach, GB;
Simon R. Stebbing, Warrington, GB;
PQ Silicas UK Limited, Barnsley, South Yorkshire, GB;
Abstract
An amorphous silica suitable for use in a dental composition has a weight mean particle size in the range 3 to 15 μm with at least 90 per cent by weight of particles having a size below 20 μm, a Radioactive Dentine Abrasion (RDA) determined on an aqueous slurry of the silica powder of 100 to 220, a Pellicle Cleaning Ratio (PCR), when incorporated in a dental composition at 10 per cent by weight, greater than 85, the ratio of PCR to RDA being in the range 0.4:1 to less than 1:1 and having a Plastics Abrasion Value (PAV) in the range 11 to 19. A silica having the above properties is prepared by a precipitation route. The silica made available by the invention is also useful as an anti-blocking agent in plastics.