Coated glass microbubbles and article incorporating them
AssigneeMinnesota Mining and Manufacturing Company
InventorsCraig S. Chamberlain, George F. Vesley, Patrick G. Zimmerman, Jerome W. McAllister
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Abstract
The invention concerns glass microbubbles having an inorganic thin-film coating not exceeding about 10 nm in thickness, especially a coating of a metal, a metalloid, or an alloy thereof. When dispersed throughout a matrix such as a polymer, the coated glass microbubbles can afford surprisingly good hiding power while also imparting esthetically pleasing colors to otherwise transparent articles.
Claims21
Glass microbubbles having an average density not exceeding 1.0 g/cm.sup.3 and an average diameter from 5 to 200 micrometers wherein the improvement comprises:
- the microbubbles have an inorganic thin-film coating having an average thickness not exceeding 10 nm.
A coherent article comprising a matrix filled with glass microbubbles comprising at least 5 volume percent of the article, wherein the improvement comprises:
- the microbubbles have an inorganic thin-film coating having an average thickness not exceeding 10 nm.
Dependencies are inferred from the claim text.