Process of making cellulated glass beads
Patent 4234330 Issued on November 18, 1980. Estimated Expiration Date: 
August 15, 1999. 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.
August 15, 1999. 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 2691248 3174870 3325341 3443920 InventorsApplicationNo. 06/066852 filed on 08/15/1979US Classes:65/21.4, Hollow or porous particle501/80, Pore-forming65/22With pore forming in situExaminersPrimary: Lindsay, Robert L.Attorney, Agent or FirmInternational ClassesC03C 11/00 (20060101)C03B 19/00 (20060101) C03B 19/10 (20060101) Foreign Application Priority Data1977-05-19 GBAbstractA process of making cellulated glass beads by forming a mixture comprising glass particles and cellulating agent into nodules, heat treating the nodules to cause fusion of glass and evolution of gas from the cellulating agent to form cellulated glass beads, and cooling the cellulated glass beads to a rigid condition. The cellulating agent utilized has the characteristic of creating expansion forces due to the evolution of gas during heat treatment which are generated wholly or mainly while the glass viscosity is within the range 106.5 to 108.5 poises. The heat treatment is carried out with a quantity of cellulating agent at a maximum cellulation temperature which is not above the temperature corresponding with a glass viscosity of 105.5 poises and for a time such that the beads immediately following the heat treatment are populated with cells, and after cooling have a bulk density of not more than 0.5 g/cm3 and a water-permeability of less than 15% by volume determined by the immersion test herein specified. | |
