Photothermographic materials incorporating arylboronic acids
View Patent ↗Incorporation of certain arylboronic acid compounds into photothermographic materials provides materials with reduced initial image D min and improved hot-dark D min print stability without unacceptable loss in sensitometric properties.
1. A black-and-white, organic solvent based photothermographic material comprising a support and having on at least one side thereof a photothermographic 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 hydrophobic polymeric binder, and
e. one or more arylboronic acid compounds represented by Structure (I)
wherein Ar represents an aromatic carbocyclic or heterocyclic group, and wherein any non-hydrogen substituent that is attached to a ring atom of Ar that is adjacent to the Ar ring atom attached to the boron atom is a bond to a fused aromatic or non-aromatic carbocyclic or heterocyclic ring,
and wherein said arylboronic acid compound is present in an amount of at least 0.5 g/m 2 .
2. The photothermographic material of claim 1
wherein said one or more arylboronic acid compounds represented by Structure (II)
wherein R 1 , R 2 , and R 3 each independently represents hydrogen, an alkyl group, a cycloalkyl group, an aryl group, a nitro group, halo group, a trihalomethyl group, a hydroxy group, an alkoxy group, an aryloxy group, a alkylthio group, an acetyl group, or a nitrile group, or R 1 and R 2 , R 1 and R 3 , or R 1 , R 2 , and R 3 can be joined together to form one or more fused aromatic or non-aromatic carbocyclic or heterocyclic rings.
3. The photothermographic material of claim 2 wherein R 1 , R 2 , and R 3 are independently hydrogen or hydroxy, halo, nitro, nitrile, or acetal groups.
4. The photothermographic material of claim 1 wherein said one or more arylboronic acid compounds represented by the following compounds (ABA-1) to (ABA-22):
5. The material of claim 1 that provides a black-and-white image and is sensitized to a wavelength of from about 600 to about 1200 nm.
6. 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 arylboronic acid compounds are present on both sides of said support.
7. The photothermographic material of claim 1 wherein the total silver is present at a coating weight of less than 2 g/m 2 on each imaging side of said support.
8. The photothermographic material of claim 1 further comprising a contrast enhancing agent.
9. The photothermographic material of claim 1 further comprising a co-developer reducing agent.
10. The photothermographic material of claim 9 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.
11. The photothermographic material of claim 10 further comprising one or more hydroxylamines, alkanolamines, ammonium phthalamate compounds, hydroxamic acids, N-acylhydrazines, or hydrogen atom donor compounds.
12. The photothermographic material of claim 1 wherein said arylboronic acid compound is present in the photothermographic emulsion layer.
13. The photothermographic material of claim 1 further comprising a protective overcoat layer disposed over said photothermographic layer, and said arylboronic acid compound having been incorporated into at least said protective overcoat layer.
14. The photothermographic material of claim 1 wherein said arylboronic acid compound is present in one or more layers in a total amount of from about 0.5 to about 15 g/m 2 .
15. The photothermographic material of claim 1 further comprising a development accelerator and one or more polyhalogen stabilizers.
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 25 seconds or less.
18. The method of claim 16 wherein said imagewise exposing is carried out using laser imaging at from about 700 to about 950 nm.
19. A black-and-white, organic solvent based photothermographic material comprising a support and having on at least one side thereof a photothermographic layer and comprising, in reactive association:
a. a photosensitive silver halide,
b. a non-photosensitive source of reducible silver ions, comprising at least silver behenate,
c. one or more reducing agents for said reducible silver ions,
d. a polyvinyl butyral or polyvinyl acetal binder, and
d. one or more arylboronic acid compounds represented by Structure (II)
wherein R 1 R 2 , and R 3 each independently represents hydrogen, an alkyl group, a cycloalkyl group, an aryl group, a nitro group, halo group, a trihalomethyl group, a hydroxy group, an alkoxy group, an aryloxy group, an alkylthio group, an acetyl group, a nitrile group, or R 1 and R 2 , or R 1 and R 3 , or R 1 , R 2 , and R 3 can be joined together to form one or more fused carbocyclic, heterocyclic, aromatic, or heteroaromatic rings, and
wherein said arylboronic acid compound is present in an amount of from 0.5 g/m 2 to about 5 g/m 2 .
20. The photothermographic material of claim 19 wherein said one or more reducing agents comprises one or more hindered phenol or hindered bis-phenol reducing agents or mixtures thereof.