Photoimaging process using nitroso dimer

Claim 3

A NONGASEOUS, ETHYLENICALLY UNSATURATED COMPOUND CAPABLE OF FORMING A HIGH POLYMER BY FREE-RADICAL INITIATED CHAIN ADDITION PROPAGATION, 2. 3 TO 95% BY WEIGHT, BASED ON THE TOTAL COMPOSITION, OF AN ORGANIC POLYMERIC BINDER HAVING A MOLECULAR WEIGHT OF AT LEAST 4000, 3. 1 TO 10% BY WEIGHT, BASED ON THE TOTAL COMPOSITION, OF AN ORGANIC, RADIATION-SENSITIVE, FREE-RADICAL GENERATING SYSTEM, AND 4. 0.1 TO 2% BY WEIGHT, BASED ON THE TOTAL COMPOSITION, OF A THERMALLY DISSOCIABLE NITROSO DIMER HAVING A DISSOCIATION CONSTANT OF 10**-2 TO 10**-10 AND A DISSOCIATION HALF-LIFE OF AT LEAST 30 SECONDS IN SOLUTION AT 25*C., THE WEIGHT RATIO OF NITROSO DIMER TO FREE-RADICAL GENERATING SYSTEM BEING LESS THAN 2 TO 1, B. EXPOSING THE PHOTOPOLYMERIZABLE COATING TO RADIATION HAVING WAVELENGTHS ESSENTIALLY LIMITED TO 3400 TO 8000A THROUGH AN IMAGE-BEARING THANSPARENCY AT A TEMPERATURE OF 50*-70*C., C. ALLOWING THE COATING TO COOL TO A TEMPERATURE BELOW 45*C. TO REDUCE THE CONCENTRATION OF NITROSO MONEMER, D. REEXPOSING A GREATER PORTION THE COATING, INCLUDING THE PORTION STRUCK BY RADIATION DURING FIRST EXPOSURE, TO RADIATION HAVING WAVELENGTHS ESSENTIALLY LIMITED TO 3400 TO 800A AT A TEMPERATURE BELOW 46*C., AND E. DEVELOPING THE RESULTING IMAGE.

Claim 4

A NONGASEOUS, ETHYLENICALLY UNSATURATED COMPOUND CAPABLE OF FORMING A HIGH POLYMER BY FREE-RADICAL INITIATED CHAIN ADDITION PROPAGATION, 2. 3 TO 95% BY WEIGHT, BASED ON THE TOTAL COMPOSITION, OF AN ORGANIC POLYMERIC BINDER HAVING A MOLECULAR WEIGHT OF AT LEAST 4000, 3. 1 TO 10% BY WEIGHT, BASED ON THE TOTAL COMPOSITION, OF AN ORGANIC, RADIATION-SENSITIVE, FREE-RADICAL GENERATING SYSTEM, AND 4. 0.1 TO 2% BY WEIGHT, BASED ON THE TOTAL COMPOSITION, OF A THERMALLY DISSOCIABLE NITROSO DIMER HAVING A DISSOCIATION CONSTANT OF 10**-2 TO 10**-10 AND A DISSOCIATION HALF-LIFE OF AT LEAST 30 SECONDS IN SOLUTION AT 25*C., THE WEIGHT RATIO OF NITROSO DIMER TO FREE-RADICAL GENERATING SYSTEM BEING LESS THAN 2 TO 1, B. EXPOSING THE PHOTOPOLYMERIZABLE COATING TO RADIATION HAVING WAVELENGTHS ESSENTIALLY LIMITED TO 3400 TO 8000A THROUGH AN IMAGE-BEARING THANSPARENCY AT A TEMPERATURE OF 50*-70*C., C. ALLOWING THE COATING TO COOL TO A TEMPERATURE BELOW 45*C. TO REDUCE THE CONCENTRATION OF NITROSO MONEMER, D. REEXPOSING A GREATER PORTION THE COATING, INCLUDING THE PORTION STRUCK BY RADIATION DURING FIRST EXPOSURE, TO RADIATION HAVING WAVELENGTHS ESSENTIALLY LIMITED TO 3400 TO 800A AT A TEMPERATURE BELOW 46*C., AND E. DEVELOPING THE RESULTING IMAGE.

Claim 5

3 to 95% by weight, based on the total composition, of an organic polymeric binder having a molecular weight of at least 4000,

Claim 6

3 to 95% by weight, based on the total composition, of an organic polymeric binder having a molecular weight of at least 4000,

Claim 7

The method of claim 1 in which the unsaturated compound contains a plurality of terminal addition polymerizable ethylenic linkages wherein at least one such linkage is conjugated with a double bonded carbon.

Claim 8

The method of claim 2 in which the unsaturated compound is an acrylic ester.

Claim 9

1 to 10% by weight, based on the total composition, of an organic, radiation-sensitive, free-radical generating system, and

Claim 10

1 to 10% by weight, based on the total composition, of an organic, radiation-sensitive, free-radical generating system, and

Claim 11

0.1 to 2% by weight, based on the total composition, of a thermally dissociable nitroso dimer having a dissociation constant of 10 2 to 10 10 and a dissociation half-life of at leat 30 seconds in solution at 25*C., the weight ratio of nitroso dimer to free-radical generating system being less than 2 to 1, b. exposing the photopolymerizable coating to radiation having wavelengths essentially limited to 3400 to 8000A through an image-bearing transparency at a temperature of 50*-70*C., c. allowing the coating to cool to a temperature below 45*C. to reduce the concentration of nitroso monomer, d. reexposing a greater portion of the coating, including the portion struck by radiation during the first exposure, to radiation having wavelengths essentially limited to 3400 to 8000A at a temperature below 45*C., and e. developing the resulting image.

Claim 12

0.1 to 2% by weight, based on the total composition, of a thermally dissociable nitroso dimer having a dissociation constant of 10 2 to 10 10 and a dissociation half-life of at leat 30 seconds in solution at 25*C., the weight ratio of nitroso dimer to free-radical generating system being less than 2 to 1, b. exposing the photopolymerizable coating to radiation having wavelengths essentially limited to 3400 to 8000A through an image-bearing transparency at a temperature of 50*-70*C., c. allowing the coating to cool to a temperature below 45*C. to reduce the concentration of nitroso monomer, d. reexposing a greater portion of the coating, including the portion struck by radiation during the first exposure, to radiation having wavelengths essentially limited to 3400 to 8000A at a temperature below 45*C., and e. developing the resulting image.

Claim 13

The method of claim 3 in which the unsaturated compound is trimethylolpropane triacrylate.

Claim 14

The method of claim 1 in which the free-radical generating system is 1 to 8% by weight, based on the total composition, of a 2,4,5-triarylimidazole dimer and a free-radical producing electron donor agent.

Claim 15

The method of claim 5 in which the free-radical generating system is 2-o-chlorophenyl-4,5-diphenylimidazole dimer and tris(4-diethylamino-2-methylphenyl)-methane.

Claim 16

The method of claim 1 in which the photopolymerizable composition contains 0.15 to 1.5% by weight, based on the total composition, of nitrosocyclohexane dimer.

Claim 17

The method of claim 1 in which the photopolymerizable composition contains 25 to 75% by weight, based on the total composition, of polymethyl methacrylate resin.

Claim 18

The method of claim 1 in which a positive-working contour image is developed by removing the nonpolymerized portion of the coating.

Claim 19

The method of claim 1 in which the weight ratio of nitroso dimer to free-radical generating system is in the range of 0.1:1 to 1.75:1.

Claim 20

The method of claim 1 in which the second exposure is at room temperature.

Claim 21

The method of claim 1 in which the unsaturated compound is trimethylolpropane triacrylate, the free-radical generating system is 1 to 8% by weight, based on the total composition, of 2-o-chlorophenyl-4,5-diphenylimidazole dimer and tris(4-diethylamino-2-methylphenyl)methane, the nitroso dimer is 0.15 to 1.5% by weight, based on the total composition, of nitrosocyclohexane dimer, and the polymeric binder is 25 to 75% by weight, based oN the total composition, of polymethyl methacrylate resin.