Back to results
US 2009/0081578 A1Published application
Method of preparing silver carboxylate soaps
AssigneeCarestream Health, Inc.
InventorsLilia P. Burleva, David R. Whitcomb
Life of this patent
Estimating the term…
Abstract
Silver salts of long chain carboxylic acids are prepared from long chain carboxylic acids by sequential addition of at least two different alkali metal hydroxides, one of which is lithium hydroxide, followed by converting the mixture of alkali metal carboxylates to silver carboxylates. Photothermographic materials prepared from such silver carboxylates display improved Dmin aging with little if any affect on other sensitometric properties.
Claims20
A method of forming a silver soap of a long chain carboxylic acid comprising:
- (A) preparing a dispersion of a long chain carboxylic acid in water, with no alkali or ammonia salt of said acid present in the dispersion while said long chain carboxylic acid is maintained above its melting point but below the boiling point of the dispersion;
- (B) converting a first portion of said long chain carboxylic acid to one or more alkali metal salts of said long chain carboxylic acid by the addition of one or more alkali metal hydroxides;
- (C) converting the remainder of said long chain carboxylic acid to one or more alkali metal salts of said long chain carboxylic acid by the addition of one or more alkali metal hydroxides;
- (D) cooling the dispersion, and thereafter;
- and
- (E) converting the mixture of said long chain alkali metal salts of said long chain carboxylic acid to a silver soap of said long chain carboxylic acid;
- so long as one of said alkali metal hydroxides in step (B) or (C) but not both is lithium hydroxide.
4 more elements
A method of preparing a photothermographic material comprising:
- (A) preparing a dispersion of a long chain carboxylic acid in water, with no alkali or ammonia salt of said acid present in the dispersion while the acid is maintained above its melting point but below the boiling point of the dispersion;
- (B) converting a first portion of the long chain carboxylic acid to one or more alkali metal salts of the long chain carboxylic acid by the addition of one or more alkali metal hydroxides;
- (C) converting the remainder of the long chain carboxylic acid to one or more alkali metal salts of the long chain carboxylic acid by the addition of one or more alkali metal hydroxides;
- (D) cooling the dispersion;
- (E) adding a performed silver halide, and thereafter;
- (F) converting the mixture of long chain alkali metal salts of the carboxylic acid to a silver soap of said long chain carboxylic acid, so long as one of the alkali metal hydroxides in step (B) or (C) but not both is lithium hydroxide;
- (G) adding a binder to form a photothermographic emulsion formulation;
- (H) adding a hindered bis-phenol reducing agent to form a photothermographic coating formulation;
- and
- (I) coating and drying said photothermographic emulsion formulation on a support to provide a photothermographic imaging material.
7 more elements
Dependencies are inferred from the claim text.