Photographic reversal bath concentrate and method of preparing same
AssigneeEastman Kodak Company
InventorsJean M. Buongiorne, Michael J. Haight
Life of this patent
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Abstract
A photographic reversal bath concentrate is formulated in such a manner as to avoid precipitates while including new biocides and excluding propionic acid. The concentrate is prepared by adding stannous ion nucleating agent to a solution of an organic phosphonic or phosphinic acid chelating agent, followed by addition of a quaternary ammonium compound as the sole biocide at a concentration of at least about 1 g/l. The quaternary ammonium compound has a molecular weight of from about 175 to about 440.
Claims20
A ready-to-use photographic reversal bath concentrate having a pH of from about 5.0 to about 5.5, and comprising:
- A) stannous chloride at a concentration of at least about 29 g/l,
- B) a quaternary ammonium compound as a sole biocide at a concentration of at least about 1 g/l, and
- C) an alkali metal salt of an organic phosphonic or phosphinic acid chelating agent at a concentration of at least about 150 g/l,
- said concentrate being free of propionic acid.
A method for preparing a photographic reversal bath concentrate having a final pH of from about 4.5 to about 5.5, and comprising the steps of, in order:
- A) forming an aqueous solution of a soluble alkali metal salt of an organic phosphonic or phosphinic acid chelating agent present at a concentration of at least about 150 g/l, and
- B) adding stannous chloride to said aqueous solution to a concentration of at least about 29 g/l,
- said method further comprising, after step A, adding to said aqueous solution as the sole biocide, a quaternary ammonium compound to a concentration of at least about 1 g/l, said quaternary ammonium compound having a molecular weight of from about 175 to about 440.
A method for preparing a photographic reversal bath concentrate having a final pH of from about 5.0 to about 5.5, comprising the steps, in order:
- A) forming an aqueous solution of aminotris(methylenephosphonic acid) chelating agent at a concentration of from about 200 to about 250 g/l,
- B) adding stannous chloride to said aqueous solution to a concentration of from about 30 to about 40 g/l,
- C) adding p-aminophenol to said aqueous solution during or after step B, but before step D, and
- D) adding as the sole biocide, myristyltrimethyl ammonium bromide, hexadecyltrimethyl ammonium bromide, or a mixture of dodecyl- tetradecyl- and hexadecyltrimethyl ammonium bromides to a concentration of from about 3 to about 4.5 g/l.
Dependencies are inferred from the claim text.