Eastman-kodak Company

James E Mitchell

Paul R West

Paul R Josephson, Jr

Gary R Miller

Raymond W Ryan, Jr

Jr, Raymond Ryan

Negative-working lithographic printing plates comprise a radiation-sensitive composition having incorporated therein a photocrosslinkable polymer, containing the photosensitive group ##STR1## as an integral part of the polymer backbone, and a print-out composition which produces an optical density difference upon exposure to activating radiation and thereby enables the exposed image on the printing plate to be seen before the plate is processed. The print-out composition comprises a leuco form of a dye having one or more removable hydrogen atoms, the removal of which forms a compound colored differently from the leuco form; a photooxidant which has a photoscissionable nitrogen-oxygen bond, the photooxidant serving to convert the leuco dye to the differently colored form when the composition is exposed to activating radiation; and a heteroaromatic amine N-oxide which functions to improve the photo-efficiency of the print-out composition and thereby increase the print-out density.

Lithographic printing plates having a radiation-sensitive layer

Radiation-sensitive compositions which are especially useful in the production of negative-working lithographic printing plates comprise a photocrosslinkable polymer, containing the photosensitive group ##STR1## as an integral part of the polymer backbone, and a print-out composition which produces an optical density difference upon exposure to activating radiation and thereby enables the exposed image on the printing plate to be seen before the plate is processed. The print-out composition comprises a leuco form of a dye having one or more removable hydrogen atoms, the removal of which forms a compound colored differently from the leuco form; a photooxidant which has a photoscissionable nitrogen-oxygen bond, the photooxidant serving to convert the leuco dye to the differently colored form when the composition is exposed to activating radiation; and a heteroaromatic amine N-oxide which functions to improve the photo-efficiency of the print-out composition and thereby increase the print-out density.

Radiation-sensitive compositions comprising a photocrosslinkable

Radiation-sensitive compositions which are especially useful in the production of negative-working lithographic printing plates comprise a photocrosslinkable polymer containing the photosensitive group ##STR1## as an integral part of the polymer backbone and, in an amount sufficient to improve the properties of the composition, a polymer of vinyl pyrrolidone. The polymer of vinyl pyrrolidone improves the properties of the radiation-sensitive composition in regard to such factors as shelf life, image contrast, and developability and thereby provides a superior lithographic printing plate.

Radiation-sensitive composition containing a vinyl pyrrolidone polymer

Radiation-sensitive compositions which are especially useful in the production of negative-working lithographic printing plates comprise a photocrosslinkable polymer containing the photosensitive group ##STR1## as an integral part of the polymer backbone and, in an amount sufficient to improve the properties of the composition, both a polymer of vinyl pyrrolidone and an unsaturated polyester such as a polyester derived from fumaric acid and a 4,4'-isopropylidine-diphenol. The combination of a polymer of vinyl pyrrolidone and an unsaturated polyester improves the properties of the radiation-sensitive composition in regard to such factors as shelf life, image contrast, developability and ink receptivity and thereby provides a superior lithographic printing plate.

Radiation-sensitive composition containing both a vinyl pyrrolidone

Radiation-sensitive compositions which are especially useful in the production of negative-working lithographic printing plates comprise a photocrosslinkable polymer containing the photosensitive group ##STR1## as an integral part of the polymer backbone and, in an amount sufficient to improve the properties of the composition, an unsaturated polyester such as a polyester derived from fumaric acid and a 4,4'-isopropylidenediphenol. The unsaturated polyester additive improves the properties of the radiation-sensitive composition in regard to processing characteristics and ink receptivity and thereby provides a superior lithographic printing plate.

Radiation-sensitive composition containing an unsaturated polyester and

Radiation-sensitive compositions which are especially useful in the production of negative-working lithographic printing plates comprise a photocrosslinkable polymer containing the photosensitive group ##STR1## as an integral part of the polymer backbone and, in an amount sufficient to improve the properties of the composition, both a poly(N-acyl-alkyleneimine) and an unsaturated polyester such as a polyester derived from fumaric acid and a 4,4'-isopropylidenediphenol. The combination of a poly(N-acylalkyleneimine) and an unsaturated polyester improves the properties of the radiation-sensitive composition in regard to such factors as shelf life, image contrast, developability, ink receptivity and reduction in mottle and thereby provides a superior lithographic printing plate.

Radiation-sensitive composition containing both a

Radiation-sensitive compositions which are especially useful in the production of negative-working lithographic printing plates comprise a photocrosslinkable polymer containing the photosensitive group ##STR1## as an integral part of the polymer backbone and, in an amount sufficient to improve the properties of the composition, a poly(N-acyl-alkleneimine). The poly(N-acyl-alkyleneimine) improves the properties of the radiation-sensitive composition in regard to such factors as shelf life, image contrast, developability and reduction in mottle and thereby provides a superior lithographic printing plate.

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Windsor, CO, United States of America

James E Mitchell