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US 5,211,885 AGranted
Squarylium dyes and products and processes using same
AssigneeSteadfast Corporation
InventorCharles M. Zepp
Life of this patent
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Abstract
A novel class of squarylium infrared absorbing dyes is disclosed which are prepared by the condensation of squaric acid with a benzoxazinone. The dyes are unique in that they possess the desirable properties of squarylium dyes in general along with a narrow band of peak absorbency greater than 1000. Because of their stability to laser beams, the dyes are particularly useful in ocular products for eye protection against lasers.
Claims10
An infrared absorbing dye of the formula:
- ##STR5## wherein:
- each R is hydrogen, alkyl having 1 to 4 carbon atoms or phenyl, including phenyl radicals substituted by one or more alkyl radicals;
- and
- each R' is hydrogen, alkyl having 1 to 6 carbon atoms, phenyl or phenalkyl.
1 more element
Dependencies are inferred from the claim text.