Preparation of very fine glass powder of high purity
Patent 5340776 Issued on August 23, 1994. Estimated Expiration Date: 
May 12, 2012. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
May 12, 2012. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3126293 3358938 3423032 3881661 Method of crushing particles of material in a ball mill Concentrated powder or granular formulations dispersable in aqueous media Complex ceramic and metallic shaped by low pressure forming and sublimative drying Patent #: 5047182 InventorsAssigneeApplicationNo. 881929 filed on 05/12/1992US Classes:501/11Glass compositions, compositions containing glass other than those wherein glass is a bonding agent, or glass batch forming compositionsExaminersPrimary: Bell, Mark L.Assistant: Wright, A. Attorney, Agent or FirmInternational ClassC03C 003/00Foreign Application Priority Data1991-01-11 DEAbstractFor the preparation of high purity glass powder having a mean particle size of ࣘ10 μm, glass powder having a larger particle size up to 300 μm is ground to the desired particle size in a stirred mill with glass grinding elements in the presence of a grinding liquid comprising water or preferably a mixture of at least 50% by weight of water and at least one water-soluble, oxygen-containing organic compound having 1 to 5 carbon atoms in the molecule, e.g., tert.-butyl alcohol; the ground slurry is then frozen, and the solvent is subsequently removed from the frozen slurry by freeze-drying. A resultant glass powder with a mean particle size d50 of 0.5 to 2 μm is particularly suitable as a filler for synthetic resins in the dental sector.Other References
Field of SearchGlass compositions, compositions containing glass other than those wherein glass is a bonding agent, or glass batch forming compositionsWith application of fluid or lubricant material With additional heating or cooling By contact between relatively moving portions of material Liquids added to make pulp or suspension With wearing away of surface material (e.g., abrading or grinding) WITH STEP OF COOLING TO A TEMPERATURE OF ZERO DEGREES C. OR BELOW | |
