The Mead Corporation

Jacqueline G Truini

Paul D Davis

David A Hutchings

Gary B Schuster

Al Fentiman

The present invention is directed to an improved method for forming photosensitive microcapsules and increasing sensitivity by incorporating a thiol into the microcapsules through diffusion while maintaining an aqueous surrounding medium at a pH of 7.0 or less.

Method for preparing photosensitive microcapsules

A photohardenable composition comprising a free radical addition polymerizable or crosslinkable compound, an ionic dye/reactive counter ion complex capable of absorbing actinic radiation and producing free radicals which initiate free radical polymerization or crosslinking of the polymerizable or crosslinkable compound, and a disulfide represented by the structure ##STR1## wherein X is selected from the group consisting of S and O except in a specific case in which the disulfide is derived from one or more tetrazolyl groups; n represents 0 or 1; A represents the residue of the ring containing the N, C and X atoms, the ring containing five or six members and, in addition, said ring members may be fused to an aromatic ring; and R.sup.5 is an aromatic radical selected from the group consisting of (i) phenyl, (ii) benzothiazolyl, (iii) benzoxazolyl, (iv) tetrazolyl, (v) pyridinyl, (vi) pyrimidinyl, (vii) thiazolyl, (viii) oxazolyl, (ix) quinazolinyl, and (x) thiadiazolyl, each of which may have a substituent on one or more C or N atoms of the ring.

Photoinitiator compositions containing disulfides and photohardenable

A photoinitiator composition comprising a compound which absorbs actinic radiation and directly or indirectly generates free radicals, and an O-acylthiohydroxamate compound or an N-alkoxypyridine thione; photohardenable compositions containing that photoinitiator composition; and photosensitive materials employing same.

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Dayton, OH, United States of America

Jacqueline G Truini