Process for making a two layer thermal negative plate

A negative-working image forming process which comprises the steps of:

• (1) flood exposing with UV radiation a photosensitive assembly that comprises:
• (a) an aluminum plate hydrophilic support which can be used as a lithographic base and having thereon;
• (b) a first layer comprising:
• (i) at least one copolymer that is soluble or dispersible in an aqueous alkaline solution and has at least one functional group selected from the group consisting of carboxylic acid, N-substituted cyclic imide, amide, and mixtures thereof;
• (c) a second layer on top of the first layer, the second layer comprising at least one o-quinonediazide compound that comprises either (i) a mixture of a phenolic resin and an o-naphthoquinone diazide compound;
• (ii) a reaction product of a resin and an o-naphthoquinone diazide compound;
• or (iii) a mixture of (i) and (ii);
• whereby the flood UV exposure causes the at least one o-quinonediazide compound to be converted to the corresponding indenecarboxylic acid compound;
• said second layer additionally containing an infrared absorbing compound;
• (2) imagewise exposing the flood UV exposed photosensitive assembly with infrared radiation to thereby convert the indenecarboxylic acid compound in the second layer in the imagewise exposed areas to the corresponding indene compound;
• and
• (3) developing the imagewise exposed photosensitive assembly with an alkaline developing solution to dissolve out the imagewise unexposed areas of the second layer and the areas of the first layer underlying the imagewise unexposed areas of the second layer and thereby producing a negative working image.

A negative-working image-forming process which comprises the steps of:

• (1) flood exposing with UV radiation a photosensitive assembly that comprises:
• (a) an anodized aluminum plate hydrophilic support which can be used as a lithographic base and having thereon;
• (b) a first layer comprising:
• (i) terpolymer of methacrylamide, methacrylic acid and N-phenylmaleimide that is soluble or dispersible in an aqueous alkaline solution;
• (c) a second layer on top of the first layer, the second layer comprising at least one o-quinonediazide compound that comprises either (i) a mixture of a phenolic resin and an o-naphthoquinone diazide compound;
• (ii) a reaction product of a resin and an o-naphthoquinone diazide compound;
• or (iii) a mixture of (i) and (ii);
• whereby the flood UV exposure causes the at least one o-quinonediazide compound to be converted to the corresponding indenecarboxylic acid compound;
• said second layer additionally containing an infrared absorbing compound;
• (2) imagewise exposing the flood UV exposed photosensitive assembly with infrared laser radiation to thereby convert the indenecarboxylic acid compound in the second layer in the imagewise exposed areas to the corresponding indene compound;
• and
• (3) developing the imagewise exposed photosensitive assembly with an alkaline developing solution to dissolve out the imagewise unexposed areas of the second layer and the areas of the first layer underlying the imagewise unexposed areas of the second layer and thereby producing a negative working image.