Photothermographic materials incorporating antifoggants
View Patent ↗Incorporation of certain compounds into photothermographic materials provides materials with reduced initial image D min and improved Raw Stock Keeping film stability without unacceptable loss in sensitometric properties. These compounds include certain e-i) zinc salts of an aryl sulfonic acid or of a fluorinated C 2 -C 6 carboxylic acid, e-ii) non-encapsulated alkali metal salts of an aryl sulfonic acid or of a fluorinated C 2 -C 6 carboxylic acid, and e-iii) fluorinated C 2 -C 6 carboxylic acids.
1. A black-and-white photothermographic material comprising a support and having on at least one side thereof a photothermographic emulsion layer and comprising, in reactive association:
a. a photosensitive silver halide,
b. a non-photosensitive source of reducible silver ions,
c. a reducing agent for said reducible silver ions,
d. a non-hydrophilic binder, and
e. one or more compounds from one or more of the following compound groups e-i), e-ii), and e-iii) that are present in a total amount of at least 5×10 −6 mol/m 2 :
e-i) zinc salts of aryl sulfonic acids or of a fluorinated C 2 -C 6 carboxylic acids,
e-ii) non-encapsulated alkali metal salts of aryl sulfonic acids or of fluorinated C 2 -C 6 carboxylic acids, with the exclusion of sodium benzenesulfonate and sodium triisopropylnaphthalenesulfonate, or
e-iii) fluorinated C 2 -C 6 carboxylic acids,
provided that said photothermographic material contains no compounds with a cyclic acid anhydride group and no non-polymeric compounds with acetal groups.
2. The photothermographic material of claim 1 comprising one or more of said e-i) compounds.
3. The photothermographic material of claim 2 comprising one or more of zinc trifluoroacetate, zinc tosylate, zinc p-dodecylbenzenesulfonate, zinc p-hydroxybenzenesulfonate, zinc m-nitrobenzenesulfonate, and zinc o-nitrobenzenesulfonate.
4. The photothermographic material of claim 1 comprising one or more of trifluoroacetic acid, nonafluorovaleric acid, sodium trifluoroacetate, zinc trifluoroacetate, sodium tosylate, zinc tosylate, zinc p-dodecylbenzenesulfonate, zinc p-hydroxybenzenesulfonate, zinc m-nitrobenzenesulfonate, and zinc o-nitrobenzenesulfonate, none of which are in encapsulated form.
5. The photothermographic material of claim 1 wherein said one or more compounds in compound groups e-i), e-ii), and e-iii) are present in an amount of from about 1×10 −5 to about 1×10 −3 mol/m 2 on each imaging side of said support.
6. The photothermographic material of claim 1 that is sensitized to a wavelength of from about 600 to about 1200 nm.
7. The photothermographic material of claim 1 having the same or different photothermographic layer on both sides of said support, and wherein said one or more of the same or different e-i), e-ii), or e-iii) compounds are present on both sides of said support.
8. The photothermographic material of claim 1 wherein the total silver is present at a coating weight of at least 1 and less than 2.6 g/m 2 on each imaging side of said support.
9. The photothermographic material of claim 1 that is organic solvent-based and said polymeric binder is a hydrophobic non-latex binder.
10. The photothermographic material of claim 1 further comprising a co-developer reducing agent.
11. The photothermographic material of claim 10 wherein said co-developer reducing agent comprises one or more trityl hydrazides, formyl phenyl hydrazides, 2-substituted malondialdehydes, 4-substituted isoxazoles, and substituted acrylonitrile compounds.
12. The photothermographic material of claim 11 further comprising one or more hydroxylamines, alkanolamines, ammonium phthalamate compounds, hydroxamic acids, N-acylhydrazines, or hydrogen atom donor compounds.
13. The photothermographic material of claim 1 wherein said one or more compounds e-i), e-ii), or e-iii) are incorporated into said photothermographic layer.
14. The photothermographic material of claim 1 further comprising a protective overcoat layer disposed over said photothermographic layer, and said e-i), e-ii), or e-iii) compound is incorporated into at least said protective overcoat layer.
15. The photothermographic material of claim 1 that is organic-solvent based and comprises a support and has on only one side thereof a photothermographic emulsion layer and comprises, in reactive association:
a. a photosensitive silver halide that is silver bromide, silver iodobromide, or both,
b. a non-photosensitive source of reducible silver ions, comprising at least silver behenate,
c. one or more monophenol, bisphenol, or trisphenol reducing agents for said reducible silver ions, or a mixture thereof,
d. a polyvinyl butyral or polyvinyl acetal binder as a binder, and
e. one or more of trifluoroacetic acid, nonafluorovaleric acid, sodium trifluoroacetate, zinc trifluoroacetate, sodium tosylate, zinc tosylate, zinc p-dodecylbenzenesulfonate, zinc p-hydroxybenzenesulfonate, zinc m-nitrobenzenesulfonate, and zinc o-nitrobenzenesulfonate, none of which is in encapsulated form, that are present in a total amount of from about 1×10 −5 mol/m 2 to about 1×10 −3 mol/m 2 .
16. A method of forming a visible image comprising:
A) imagewise exposing the photothermographic material of claim 1 to electromagnetic radiation to form a latent image, and
B) simultaneously or sequentially, heating said exposed photothermographic material to develop said latent image into a visible image.
17. The method of claim 16 wherein said development is carried out for at least 3 and up to and including 25 seconds.
18. The method of claim 16 wherein said imagewise exposing is carried out using laser imaging at from about 700 to about 950 nm.