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US 6,653,356 B2Granted
Nanoparticulate titanium dioxide coatings, and processes for the production and use thereof
OwnerJonathan Shermaninventor
Life of this patent
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Abstract
Nanoparticulate titanium dioxide coating produced by educing flocculates of titanium dioxide nanoparticles from a titanyl sulfate solution and dispersing the nanoparticles in a polar sol-forming medium to make a sol suitable as a coating usable to impart photocatalytic activity, U.V. screening properties, and fire retardency to particles and to surfaces. The photocatalytic material and activity is preferably localized in dispersed concentrated nanoparticles, spots or islands both to save costs and leverage anti-microbial effects.
Claims4
A process of producing a sol of particulate titanium dioxide comprising:
- a) mixing an alkaline-reacting liquid with an aqueous solution of titanyl sulphate at elevated temperature until the resultant mixture reacts acidically and is neutralized to a pH between 5 and 9, forming flocculates of titanium dioxide nanoparticles;
- b) first-isolating the formed titanium dioxide nanoparticle flocculate;
- c) first-washing in water the isolated titanium dioxide nanoparticle flocculate;
- d) second-washing in an acid or an alkali the first-isolated and first-washed nanoparticle flocculate,
- e) second-isolating as a product of the second-washing an acidic or an alkaline titania concentrate of titanium dioxide;
- and
- f) dispersing the second-isolated titania concentrate in a polar sol-forming medium to make a sol suitable to serve as a coating in which sol is present particulate titanium dioxide.
4 more elements
Dependencies are inferred from the claim text.