The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 08, 1985
Filed:
Jul. 30, 1984
Irena Y Bronstein-Bonte, Newton, MA (US);
Edward P Lindholm, Brookline, MA (US);
Polaroid Corporation, Cambridge, MA (US);
Abstract
Polymeric optical filter agents and products and processes using same are disclosed. The polymeric optical filter agents are pH-sensitive materials comprising a polymeric backbone having a plurality of pendant moieties of the formula (I). ##STR1## wherein X is ##STR2## and R is alkyl, aryl, alkaryl or aralkyl; A is hydrogen, alkyl or the radical ##STR3## where each of Y.sup.1, Y.sup.2 and Y.sup.3 is hydrogen or an electron-withdrawing group; and each Z.sup.1, Z.sup.2 and Z.sup.3 is hydrogen or an electron-withdrawing group; with the proviso that, when each of Z.sup.1, Z.sup.2 and Z.sup.3 is hydrogen, said A is a radical ##STR4## wherein at least one of said Y.sup.1, Y.sup.2 and Y.sup.3 groups comprises an electron-withdrawing group. These agents upon contact with alkali are converted from a substantially non-light absorbing form to a highly colored light-absorbing form useful in photographic products.