Sensitizing a thermographic silver halide photographic material with monomeric amide

Claim 2

In the process of making a light-sensitive heat-developable dry silver sheet material containing (a) photosensitive silver halide catalyst-forming means and (b) heat-sensitive reactant image-forming means including an organic silver salt oxidizing agent and a reducing agent for silver ion, the oxidation reduction reaction of which, to produce a visible change, is accelerated by said catalyst, the improvement comprising: mixing with the organic silver salt, prior to halidization thereof, a spectrally inert sensitizing amide, and thereafter halidizing a minor proportion of said organic silver salt, wherein said sensitizing amide is a monomeric amide having the structure: R 1 conr 2 r 3 , r 1 r 2 nconr 3 r 4 or (R 1 R 2 N) 3 PO wherein one of the R groups represents hydrogen or a hydrocarbon radical having no more than twelve carbon atoms and the remaining R groups represent monovalent hydrocarbon having no more than twelve carbon atoms or substituted hydrocarbon radicals having no more than twelve carbon atoms or two of said remaining R groups represent a divalent hydrocarbon radical having no more than twelve carbon atoms or hydrocarbonoxy radical having no more than twelve carbon atoms, with the proviso that none of R 1 , R 2 , R 3 , and R 4 in the formula R 1 r 2 nconr 3 r 4 may be hydrogen.

Claim 3

Process of claim 1 wherein said amide is a 2-pyrrolidinone.

Claim 4

Process of claim 1 wherein said amide is a 2-pyridone.

Claim 5

Process of claim 1 wherein said amide is a 2-piperidone.

Claim 6

Process of claim 1 wherein said amide is a substituted urea of the formula: R 1 r 2 nconr 3 r 4 wherein R 1 - R 4 are as defined above.

Claim 7

Process of claim 1 wherein said amide is a tertiary amide.

Claim 8

Process of claim 1 wherein the molar ratio of said amide to said salt is between one-hundredth and two.

Claim 9

Process of claim 7 wherein said molar ratio is approximately unity.

Claim 10

A light-sensitive heat developable dry silver sheet material comprising (a) photosensitive silver halide catalyst forming means and (b) heat-sensitive reactant image-forming means including an organic silver salt oxidizing agent and a reducing agent for silver ion, further comprising a monomeric spectrally inert organic sensitizing amide added prior to halidization of said organic silver salt and having a photographic speed of at least 5 compared to an otherwise identical sheet material free of said amide and wherein the speed is taken as unity, speed being measured by sensitometric exposure to a 6100°K light source and heat development for 30 seconds at 260°F, said sensitizing amide being represented by the formulae: R 1 conr 2 r 3 , r 1 r 2 nconr 3 r 4 or (R 1 R 2 N) 3 PO wherein one of the R groups represents hydrogen or a hydrocarbon radical having no more than twelve carbon atoms and the remaining R groups represent monovalent hydrocarbon having no more than twelve carbon atoms or substituted hydrocarbon radicals having no more than twelve carbon atoms or two of said remaining R groups represent a divalent hydrocarbon radical having no more than twelve carbon atoms or hydrocarbonoxy radical having no more than twelve carbon atoms, with the proviso that none of R 1 , R 2 , R 3 , and R 4 in the formula R 1 r 2 nconr 3 r 4 may be hydrogen.

Claim 11

A light-sensitive heat developable dry silver sheet material comprising (a) photosensitive silver halide catalyst forming means and (b) heat-sensitive reactant image-forming means including an organic silver salt oxidizing agent and a reducing agent for silver ion, further comprising a monomeric spectrally inert organic sensitizing amide added prior to halidization of said organic silver salt and having a photographic speed of at least 5 compared to an otherwise identical sheet material free of said amide and wherein the speed is taken as unity, speed being measured by sensitometric exposure to a 6100°K light source and heat development for 30 seconds at 260°F, said sensitizing amide being represented by the formulae: R 1 conr 2 r 3 , r 1 r 2 nconr 3 r 4 or (R 1 R 2 N) 3 PO wherein one of the R groups represents hydrogen or a hydrocarbon radical having no more than twelve carbon atoms and the remaining R groups represent monovalent hydrocarbon having no more than twelve carbon atoms or substituted hydrocarbon radicals having no more than twelve carbon atoms or two of said remaining R groups represent a divalent hydrocarbon radical having no more than twelve carbon atoms or hydrocarbonoxy radical having no more than twelve carbon atoms, with the proviso that none of R 1 , R 2 , R 3 , and R 4 in the formula R 1 r 2 nconr 3 r 4 may be hydrogen.