Radiation imagery chemistry: process – composition – or product th – Nonradiation sensitive image processing compositions or... – Developer
Reexamination Certificate
2001-10-18
2003-04-15
Le, Hoa Van (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Nonradiation sensitive image processing compositions or...
Developer
C430S490000, C430S493000
Reexamination Certificate
active
06548235
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to aqueous p-phenylenediamine-type photographic color developer compositions and methods for making p-phenylenediamine-type free-base photographic color developers in aqueous form. Specifically, the present invention relates to a useful p-phenylenediamine free base color developer in an aqueous alkali metal or alkaline earth metal salt form. More particularly, the present invention pertains to an alkali metal or alkaline earth metal salt composition of N-ethyl-N-2-(methanesulfonylaminoethyl)-2-methyl-p-phenylenediamine (CD-3) color developer.
The present invention further pertains to methods of making the p-phenylenediamine free base color developer in the aqueous alkali metal or alkaline earth metal salt form.
BACKGROUND OF THE INVENTION
The present invention relates to the manufacture of solutions of p-phenylenediamine-type photographic color developers in the free base form, i.e., a phenylenediamine devoid, or essentially devoid, of any acid addition salt of the phenylenediamine. p-phenylenediamine free bases have broad industry utility for the preparation of photographic finishing formulations which require a p-phenylenediamine color developer in the free base, rather than the salt, form.
The photographic finishing industry is comprised of three primary segments: the manufacture of photographic chemicals to supply photochemical formulators, the formulation of these chemicals into useful compositions for photochemical processing, and the processing of sensitized photographic color elements. Formulated photographic processing (photofinishing) solutions provided to the processors are complex, multi-part, multi-component mixtures, the specific compositions of which vary significantly according to the intended use and the formulator. Generally, the types of materials which are ultimately mixed and delivered to the processing bath include water; solubilizing agents, e.g., organic co-solvents; bases for pH control; color developing agents or color developers; preservatives; sequestering agents; buffering agents; clarifying agents; stain-reducing agents; anti-bacterial or anti-fungal agents; surfactants, and other function-specific materials.
The active component of the formulation which effects the formation of color upon processing (development) of the sensitized photographic color element (exposed film) is the free-base color developer. The color developers most commonly present in photofinishing compositions are p-phenylenediamine compounds such as N,N-dialkyl-p-phenylenediamines. These N,N-dialkyl-p-phenylenediamines vary in structure by substitution of the N-alkyl group or the ring. Specific examples of p-phenylenediamine color developers include N,N-diethyl-2-methyl-p-phenylenediamine monohydrochloride (CD-2), N-ethyl-N-2-(methanesulfonylaminoethyl)-2-methyl-p-phenylenediamine sesquisulfate monohydrate (CD-3), and N-ethyl-N-2-(hydroxyethyl)-2-methyl-p-phenylenediamine sulfate (CD-4), listed here in the commonly used acid salt form.
Traditionally, photographic finishing solutions have consisted of multiple parts which are mixed by the photographic processor or photofinisher just prior to use. Multiple parts are often required in order to separate and preserve the chemical activity and solubility of components that may otherwise deteriorate or react with each other when they are stored together for long periods of time under alkaline conditions. For example, one part might include a color developing agent in the form of an acid salt of a p-phenylenediamine color developer, specific examples of which are listed above, typically in the form of a stabilized aqueous solution. These solutions are acidic since the color developer is formulated in this part as the acid salt.
Another part typically contains a base or combination of bases which, upon mixing of the parts, serves to neutralize the acid associated with the part containing the color developer and to establish the desired alkalinity of the mixed color developing composition. Another part may contain agents to preserve the alkalinity of the mixed color developing composition. Still another part may include an optical brightener. Upon combination of all parts and water, a homogeneous color developing composition can usually be obtained for the working strength solution in the processing machine.
Other function-specific materials listed above may be incorporated in these or other parts to provide a homogenous color developing composition of appropriate working strength in the processing machine. Because the resultant and desired pH of the complete, mixed photographic finishing solution is alkaline, typically having a pH of from 9-13, the active color developer in the final, fully mixed, photographic finishing composition is not the acid salt of the color developer, but the corresponding free base. The term “free base” refers to phenylenediamine compounds devoid, or essentially devoid, of acid addition salts of phenylenediamines.
It is generally known that the concentrations of various photographic chemicals used in a photographic processing bath must lie within certain narrow limits in order to provide optimal performance. The most important solvent for such photo processing is water. Most inorganic salts can be readily dissolved in water while the organic photo chemicals in such processing baths usually have suitable solubility in water at the desired operating concentrations.
For these reasons, photofinishers prefer to use a single photo finishing solution composition which contains a plurality of the parts formerly kept separate to avoid undesired reactions and/or decomposition. Moreover, there has been a desire in the industry to provide compositions that can be used right out of their containers without the need for mixing various components (thereby reducing mixing errors), such as in what are known as “automatic replenishing” processors. The use of such combined photo finishing solutions results in simplicity of operation with a reduction in the potential for mixing errors, poor photo processing results and user need not pay for the transport or storage of large volumes of water.
The major incompatibility of the traditional parts of photo finishing solutions is between the acidic aqueous part, containing the acid salt of the color developer, and the alkaline part, containing the base or combination of bases. Since the active color developer in the final, mixed photo finishing composition is the free base form of the color developer, full consolidation of parts to produce a single-part formulation requires a source of p-phenylenediamine free base as the necessary ingredient.
Heretofore, p-phenylenediamine color developers in their free base form have not been available from the manufacturing segment of the industry. Accordingly, formulators have had to employ various procedures to produce the free bases from the corresponding p-phenylene acid salts. In preparing combined photo finishing solutions, formulators may form the p-phenylenediamine free base in situ as described in U.S. Pat. No. 5,273,865 from the p-phenylenediamine acid salt, leaving the neutralization products in the mixture. Alternatively, the p-phenylenediamine free base may be derived by neutralizing the corresponding acid salt followed by extraction into an organic solvent/water mixture, such as described in U.S. Pat. No. 6,017,687.
P-phenylenediamine free bases are intermediates to the preparation of p-phenylenediamine color developer acid salts and are manufactured commercially as non-isolated intermediates by the reduction of the corresponding nitroso or nitro precursors in polar solvents such as low molecular weight alcohols or ethers. For example, U.S. Pat. No. 3,920,739 discloses the catalytic hydrogenation of the corresponding nitro precursor in water, methanol, ethanol, n- or iso-propanol, dioxane, or dipropyl ether over a variety of noble metal catalysts. After completion of the reaction, the catalyst is removed by filtration and the N,N-disubstituted p-phenylene
Eastman Chemical Company
Graves, Jr. Bernard J.
Le Hoa Van
Wood Jonathan
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