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US 4,382,134 AGranted
3-Substituted-7-alkoxy-spiro(2H -1-benzopyran-2,3'-(3H)-naphtho(2,1-B)pyrans)
AssigneeArmstrong World Industries, Inc.
InventorsJohn E. Herweh, Thomas B. Garrett, Alan B. Magnusson
Life of this patent
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Abstract
Substituted spiropyrans particularly suitable for use as precursors to stable pyrylium salts are disclosed.
Claims4
A spiropyran compound having the formula ##STR6## wherein R represents alkylene aryl, aryl, unsaturated alkyl or cycloalkyl and R' is alkoxy.
Dependencies are inferred from the claim text.