Thermal insulating material and method of manufacturing same
AssigneeInnovation Associates, Inc.
InventorTimothy M. Henderson
Life of this patent
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Abstract
Hollow microspheres produced by the present method each have a hollow interior evacuated of gases to a predetermined pressure. A reflective material layer coats the exterior of each microsphere and, optionally, an outer layer of a protective material is applied over the reflective material layer. Permeant gases are dissolved into glass or plastic frit particles prior to heating of the frit particles to form hollow microspheres having the permeant gases contained therein. The permeant gases are subsequently out-permeated in a non-permeant gas atmosphere to substantially evacuate the interior of each microsphere. The exterior layers of reflective material and protective material are then coated about each evacuated microsphere.
Claims12
A method of producing an evacuated microsphere comprising the steps of:
- forming particles;
- dissolving permeant gases into the particles;
- heating the gas permeated particles to blow each particle into a shell containing only the permeant gases in a hollow interior of the shell while excluding gases from outside the shell which cannot be readily out permeated from the hollow interior of each shell at a low temperature;
- and
- out-permeating the permeant gases from the hollow interior of the shells in a gas atmosphere composed of gases having permeabilities much lower than that of the permeant gases within the shell to evacuate the interior of the shells to a pressure of .ltoreq.10.sup.-4 Torr and to thereby remove substantially all of the gases from the interior of the shell at any temperature.
Dependencies are inferred from the claim text.