Back to results
US 7,087,366 B2Granted
Method for chemical sensitization of silver halide for photothermographic use
AssigneeEastman Kodak Company
InventorsLilia P. Burleva, Kumars Sakizadeh, David R. Whitcomb, Sharon M. Simpson
Life of this patent
Estimating the term…
Abstract
A photothermographic emulsion is prepared by chemically sensitizing silver halide grains formed by oxidative decomposition of a diphenylphosphine sulfide compound on or around the silver halide grains. This procedure uses a unique sequence of steps and provides increased photographic speed and manufacturing reproducibility.
Claims23
A method of preparing a photothermo-graphic emulsion comprising:
- (A) providing a photothermographic dispersion of preformed photosensitive silver halide grains and a non-photosensitive source of reducible silver ions, and performing the following steps in order,
- (B) providing one or more diphenylphosphine sulfide compounds, in association with said preformed photosensitive silver halide grains and the non-photosensitive source of reducible silver ions, said diphenylphosphine sulfide compound being represented by the following Structure PS:
- wherein Ph1 and Ph2 are the same or different phenyl groups, R1 and R2 are each independently hydrogen or an alkyl or phenyl group, L is a direct bond or a divalent linking group, m is 1 or 2 and when m is 1, R3 is a monovalent group and when m is 2, R3 is a divalent aliphatic linking group having 1 to 20 carbon, nitrogen, oxygen, or sulfur atoms in the chain,
- (C) chemically sensitizing said preformed photosensitive silver halide grains by decomposing the diphenylphosphine sulfide compound represented above by Structure (PS) on or around said preformed photosensitive silver halide grains in an oxidizing environment to provide a photothermographic emulsion comprising chemically sensitized preformed photosensitive silver halide grains in reactive association with said non-photosensitive source of reducible silver ions, and
- (D) converting some of said reducible silver ions in said non-photo-sensitive source of reducible silver ions into photosensitive silver halide grains.
2 more elements
A method of preparing a black-and-white photothermographic emulsion comprising:
- (A) providing a photothermographic dispersion of preformed photosensitive silver halide grains and a non-photosensitive source of reducible silver ions, and performing the following steps in order:
- (B) providing one or more diphenylphosphine sulfide compounds in association with said preformed photosensitive silver halide grains and said non-photosensitive source of reducible silver ions, said one or more diphenylphosphine sulfide compounds selected from at least one of the following compounds PS-1 to PS-19:
- (C) chemically sensitizing said preformed photosensitive silver halide grains by decomposing said one or more diphenyiphosphine sulfide compounds on or around said preformed photosensitive silver halide grains by the addition, in one or more stages, of pyridinium hydrobromide perbromide to the silver halide grains at from about 20° C. to about 30° C. for up to 60 minutes, to provide a photo-thermographic emulsion comprising chemically sensitized preformed photosensitive silver bromide grains in reactive association with said non-photosensitive source of reducible silver ions comprising silver behenate,
- (D) converting from about 0.1 to about 10 mol % of the reducible silver ions in said non-photosensitive source of reducible silver ions into photosensitive silver bromide grains by addition of a bromide salt.
1 more element
A method of preparing a photothermo-graphic material comprising:
- (A) providing a photothermographic dispersion of a preformed photosensitive silver halide grains and a non-photosensitive source of reducible silver ions, and performing the following steps in order,
- (B) providing one or more diphenylphosphine sulfide compounds in association with said preformed photosensitive silver halide grains and said non-photosensitive source of reducible silver ions, said diphenylphosphine sulfide compound being represented by the following Structure PS:
- wherein Ph1 and Ph2 are the same or different phenyl groups, R1 and R2 are each independently hydrogen or an alkyl or phenyl group, L is a direct bond or a divalent linking group, m is 1 or 2 and when m is 1, R3 is a monovalent group and when m is 2, R3 is a divalent aliphatic linking group having 1 to 20 carbon, nitrogen, oxygen, or sulfur atoms in the chain,
- (C) chemically sensitizing said preformed photosensitive silver halide grains by decomposing said one or more diphenyiphosphine sulfide compounds on or around said preformed photosensitive silver halide grains in an oxidizing environment to provide a photothermographic emulsion comprising chemically sensitized preformed photosensitive silver halide grains in reactive association with said non-photosensitive source of reducible silver ions,
- (D) converting some of the reducible silver ions in said non-photo-sensitive source of reducible silver ions into photosensitive silver halide grains.
- (E) simultaneously with any of steps (A) through (D), or subsequently to step (D), adding a binder to form a photothermographic emulsion formulation, and
- (F) after step (E), coating and drying said emulsion formulation on a support to provide a photothermographic material.
4 more elements
Dependencies are inferred from the claim text.