Eastman-kodak Company

Raymond W Ryan, Jr

Gary R Miller

Paul R West

James E Mitchell

Paul R Josephson, Jr

John E Walls

A negative-working lithographic printing plate having a radiation-sensitive layer comprising a diazo resin, an acid-substituted ternary acetal polymer and an unsaturated polyester is developed with an aqueous developing composition comprising an organic solvent, an anionic surface active agent, sodium oxalate, sodium nitrate or an alkali metal tetraborate an aliphatic monocarboxylic acid, an aliphatic dicarboxylic acid and sufficient alkaline buffering system to provide an alkaline pH. The method effectively avoids problems of blinding and background sensitivity which are of critical concern in the printing art.

Method for developing lithographic printing plates

Aqueous alkaline developing compositions useful in the development of negative-working lithographic printing plates are comprised of an organic solvent, an anionic surface active agent, sodium oxalate, sodium nitrate or an alkali metal tetraborate, an aliphatic monocarboxylic acid, an aliphatic dicarboxylic acid and sufficient alkaline buffering system to provide an alkaline pH. The developing composition is resistant to oxidation, highly effective in dissolution-type processing, and able to effectively desensitize the background areas of the printing plate.

Aqueous developer for lithographic printing plates with improved

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.

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Fort Collins, CO, United States of America

Raymond W Ryan, Jr