Imaging medium
AssigneePolaroid Corporation
InventorsJurgen M. Grasshoff, John L. Marshall, Richard A. Minns, Mark R. Mischke, Anthony J. Puttick, Lloyd D. Taylor, Stephen J. Telfer
Life of this patent
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Abstract
Acid can be generated by exposing a superacid precursor to actinic radiation effective to generate superacid from the superacid precursor and heating the superacid in admixture with a secondary acid generator capable of undergoing thermal decomposition to produce a secondary acid. The superacid catalyzes decomposition of the secondary acid generator, thus increasing the quantity of strong acid present in the medium. The resultant secondary acid can be used to effect a color change in an acid-sensitive material, so providing an imaging process.
Claims12
An imaging medium comprising:
- a superacid precursor capable of generating a superacid upon exposure to actinic radiation;
- and
- a secondary acid generator capable of undergoing thermal decomposition to produce a secondary acid, the thermal decomposition of the secondary acid generator being catalyzed by the superacid,
- the secondary acid generator being selected from the group consisting of:
- (a) a 3,4-disubstituted-cyclobut-3-ene-1,2-dione in which at least one of the 3- and 4-substituents consists of an oxygen atom bonded to the squaric acid ring, and an alkyl or alkylene group, a partially hydrogenated aryl or arylene group, or an aralkyl group, bonded to said oxygen atom, said 3,4-disubstituted-cyclobut-3-ene-1,2-dione being capable of decomposing so as to cause replacement of the or each original alkoxy, alkyleneoxy, aryloxy, aryleneoxy or aralkyloxy group of the derivative with a hydroxyl group, thereby producing squaric acid or an acidic squaric acid derivative having one hydroxyl group;
- and
- (b) an oxalic acid diester capable of thermal decomposition to form oxalic acid or an oxalic acid monoester having one carboxyl group.
Dependencies are inferred from the claim text.