Radiation sensitive diazo sulfo-acrylic adducts and method for producing a printing plate

A radiation sensitive element comprising a substrate and a radiation sensitive layer consisting essentially of an adduct of a diazonium resin, having a plurality of pendant diazonium groups, and a sulfonated acrylic copolymer having a plurality of pendant sulfonate groups, wherein the sulfonated acrylic copolymer comprises at least one acrylic moiety, a sulfonated moiety, and optionally a styryl moiety;

• wherein the copolymer has the structure:
• ##STR7## with the proviso that the moieties may be randomly distributed within the copolymer;
• wherein the combination of x, y, and z taken together is 100 weight %, x is about 20 weight % or more, y is between about 1 weight % and about 20 weight % and z is about 50 weight % or less;
• wherein the sulfonated acrylic polymer has a weight average molecular weight between about 5000 and about 100,000;
• and wherein R.sub.a, R.sub.b, and R.sub.c are independently selected from H or methyl, R.sub.1 is an alkyl, aryl or aralkyl group having 1 to 18 carbon atoms and Q has a phenylene structure --Ph--W--, or a carbonyl structure --CO--U--R.sub.4 --, wherein when Q has the phenylene structure, W is a covalent bond or is an alkylene group having 1 to 6 carbon atoms, or a group having the structure:
• --R.sub.2 --NH--CO.sub.2 --R.sub.3 -- wherein R.sub.2 and R.sub.3 are independently selected from alkylene groups having 1 to 6 carbon atoms, and when Q has the carbonyl structure, U is O or NH;
• R.sub.4 is an alkylene group having 1 to 6 carbon atoms, or a group having the structure:
• --R.sub.5 --Z--CO.sub.2 --R.sub.6 -- wherein R.sub.5 and R.sub.6 are independently selected from alkylene groups having 1 to 6 carbon atoms and Z is an NH group or a covalent bond.

A method for producing a printing plate from a radiation sensitive element comprising (I) imagewise exposing the radiation sensitive element to actinic radiation, wherein the radiation sensitive element comprises a substrate having a front hydrophilic surface;

• and a developer-soluble, radiation sensitive layer adhered to the front hydrophilic surface, the radiation sensitive layer consisting essentially of an adduct of a diazonium resin having a plurality of pendant diazonium groups, with a sulfonated acrylic copolymer having a plurality of pendant sulfonate groups, wherein the sulfonated acrylic copolymer comprises at least one acrylic moiety, a sulfonated moiety, and optionally a styryl moiety;
• wherein the copolymer has the structure:
• ##STR8## with the proviso that the moieties may be randomly distributed within the copolymer;
• wherein the combination of x, y, and z taken together is 100 weight %, x is about 20 weight % or more, y is between about 1 weight % and about 20 weight % and z is about 50 weight % or less;
• wherein the sulfonated acrylic copolymer has a weight average molecular weight between about 5000 and about 100,000;
• and wherein R.sub.a, R.sub.b, and R.sub.c are independently selected from H or methyl, R.sub.1 is an alkyl, aryl or aralkyl group having 1 to 18 carbon atoms, and Q has a phenylene structure --Ph--W--, or a carbonyl structure --CO--U--R.sub.4 --, wherein when Q has the phenylene structure, W is a covalent bond or an alkylene group having 1 to 6 carbon atoms, or a group having the structure:
• --R.sub.2 --NH--CO.sub.2 --R.sub.3 -- wherein R.sub.2 and R.sub.3 are independently selected from alkylene groups having 1 to 6 carbon atoms, and when Q has the carbonyl structure, U is O or NH;
• R.sub.4 is an alkylene group having 1 to 6 carbon atoms, or a group having the structure:
• --R.sub.5 --Z--CO.sub.2 --R.sub.6 -- wherein R.sub.5 and R.sub.6 are independently selected from alkylene groups having 1 to 6 carbon atoms and Z is an NH group or a covalent bond;
• whereby areas of the radiation sensitive layer which are exposed are rendered insoluble in a developer solution;
• and (II) applying the developer to the imagewise exposed radiation sensitive layer.