US 2682465 A
Description (OCR text may contain errors)
June 29, 1954 E, s WHTALA r 2,682,465
METHOD OF PACKAGING AND STABILIZING SINGLE-POWDER DEVELOPERS Filed June 26. 1952 //////////////r/r///////// /7 a 0..
SINGL E POWDER PIT/OTUfiRAPH/C DEVELOPER PE/PMEABLE 5/46 CONTZI/N/NG 3 TA BIL/2E R A'ITORNEI S Patented June 29, 1954 METHOD OF PACKAGING AND STABILIZIN G SINGLE-POWDER DEVELOPERS Edwin S. Wiitala and Donald J. Kridel, Rochester, N. Y., assignors to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey Application June 26, 1952, Serial No. 295,783
5 Claims. 1
This invention relates to single-powder photographic developers, and more particularly to a method of packaging and stabilizing the singlepowder mixture to prevent disadvantageous interaction between the organic developer compartment and the basic component of the singlepowder mixture.
Single-powder developer mixtures may contain an organic developer component or mixtures of such components, including monomethylpara-- aminophenol sulfiate (elon or metol), hydroquinone, p-aminophenol hydrochloride, p-aminophenol sulfate, pyrogallol, parahydroxyphenyl glycine, catechol, diaminophenol hydrochloride and others, with an alkali component, a stabilizing component, an oxidizing preventer and an anti-fogging component. The alkali component may be the stable hydrate of an alkali carbonate, a desiccated alkali carbonate, an alkali metaborate, or an alkali sulfite. Generally the stable alkali carbonate monohydrate is preferred. The oxidation preventing component may be an alkali sulfite, and the anti-fogging component may be potassium bromide or iodide. Stabilizing components for such a single-powder developer are disclosed in Patent 2,384,592 of September 11, 1945, and include maleic anhydride, salicylic acid, alkali metabisulfite, benzoic anhydride, orthobenzoic sulfamide, phthalamide and phthalic anhydride. The latter has outstanding stabilizing properties in the presence of either sodium carbonate or borax and has been employed considerably more than the other stabilizers mentioned in that patent.
While the stabilizing effect of the phthalic anhydride is very good, it has been employed most successfully in developer compositions having as the alkali component either sodium carbonate or sodium sulfite, or mixtures thereof. Less success has been attained in the case of the important class of developers containing sodium metaborate as the alkali ingredient. Also, the presence of phthalic anhydride in the single-powder developer involves other considerations which are not too desirable.
In the first place, phthalic anhydride is slowly soluble in water. Furthermore, it is impossible to employ it in the presence of benzotriazole, the latter being a desirable component of certain developer mixtures. But the greatest disadvantage of employing phthalic anhydride in single-powder developer mixtures, which contain alkali carbonates and sulfite, is that phthalic anh dride may react, due in part to temperature eiiects, with these basic substances and form gas under sufiicient pressure to distend the hermetically sealed can in which the developer powder is packaged, and often cause a portion or" the powder to be ejected with some violence as the package is opened.
In the copending application by William J. Rogers, Serial No. 210,284, filed February 9, 1951, now Patent No. 2,606,118, entitled Stabilizing Agent for Single Powder Photographic Developers, the effective and improved stabilization of single-powder photographic developers is accomplished by intimately mixing boric anhydride with the other components of the single-powder developer mixture.
We have now found a novel way of employing boric anhydride and other stabilizers to stabilize certain of these single-powder photographic developers without actually incorporating the stabilizer into the mixture.
An object, therefore, of the present invention is a novel method of stabilizing single-powder photographic developers.
Another object of this invention is a novel method of packaging and a novel package for single-powder photographic developers.
Other objects will appear hereinafter.
In accordance with the present invention we have found another method of employing stabilizers to stabilize single-powder photographic developers as well as a novel method for packaging such powders in a package.
We have found that instead of incorporating the powdered stabilizer into the photographic developer mixture, the same beneficial stabilizing effect may be achieved by enclosing an amount of the stabilizer in a relatively small permeable bag, and placing the permeable bag Within the hermetically sealed container in which the ingredients comprising the single-powder developer are packaged. The bag may be made from cloth, the meshes of which are smaller than the crystals of the stabilizer, or other permeable material such as paper. This is a very interesting discovery and although the theory of its operation has not been completely proved, it nevertheless is an effective method for preserving single-powder developers against self-deterioration while in a container.
An amount of stabilizer up to of the total weight of the other constituents may be employed eifectively. No particular advantage is found when a larger amount is employed.
The following examples will serve further to illustrate the method of packaging and stabilizing single-powder developer mixtures according to our invention.
Example 1 A thoroughly mixed single-powder photographic developer composition comprising:
was placed in a metal can. A small paper bag containing 2.0 grams of boric anhydride was then placed in the can and the cover hermetically sealed thereon. After prolonged storage at temperatures as high as 100 F. no interaction between the components of the mixture was evident, and the mixture had unimpaired developing properties thus showing that boric anhydride thus placed in the can was efiective in preventing deterioration of the developer. A check sample placed in a can without the bag of boric anhydride and heated to 100 F. was found to have reacted, was discolored and had diminished developing properties.
Example 2 A thoroughly mixed single-powder photographic developer composition comprising:
Grams Elon 5.2 Anhydrous sodium sulfite 45.0 I-Iydroquinone 12.0 Sodium carbonate monohydrate 81.4 Potassium bromide 2.0
was placed in a metal can. A permeable cloth bag containing two grams of powdered metaboric acid was then placed in the can and the cover hermetically sealed thereon. On exposure to temperatures of the order of 100 to 120 F. no gas formation was noted, nor was there evidence of interaction between the various ingredients of the mixture. It had the desired developing properties. A check sample heated in a can not having the bag of metaboric acid discolored badly and had a diminished developing property.
Example 3 A thoroughly mixed single-powder photographic developer composition comprising:
Grams Elon 5.2 Hydroquinone 12.0 Anhydrous sodium sulfite 45.0 Sodium carbonate monohydrate 81.4 Potassium bromide 2.0
was placed in a metal can. A paper bag containing a mixture of 1.8 grams of powdered boric and anhydride and 0.2 phthalic anhydride was then placed in the can and the cover hermetically sealed thereon. On exposure to extremes of temperature in the vicinity of 100 F. it was found that the mixed stabilizer effectively stabilized the single-powder against disadvantageous 4 chemical reaction. The powder then was used successfully as a developer. A check sample stored in a similar can not containing the bag of mixed stabilizer was badly deteriorated.
Example 4 A homogeneously mixed single-powder photographic developer composition comprising:
Sodium carbonate monohydrate 81.4
was placed in a container. A permeable cloth bag containing a mixture of 1.8 grams metaboric acid and 0.2 gram phthalic anhydride was then placed in the container and the cover hermetically sealed thereon. The container was exposed to a temperature of 110 F. for ten hours. The single-powder was then employed in a developing process and was found to be unchanged and to have undiminished developing properties. A check sample in a similar container having no bag of this mixed stabilizer showed evidence of considerable deterioration under similar treatment.
In preparing a developer solution, the compositions of the above examples should be dissolved in water to make one liter of solution.
In the accompanying drawing there is shown an elevational view in section of a container comprising a body I0 and a tight fitting cover II. A single-powder photographic developer is shown at l2. A closed small mesh cloth bag [3 filled with the selected stabilizer I4 is positioned within the can. As shown in the drawing the bag may be positioned more or less in the middle of the 4D developer mixture.
Example 5 Grams Pyrogallol 6.4 Sodium sulfite (anhydrous) 50.0 Sodium carbonate monohydrate 54-0 Potassium bromide 1.0
This formula was thoroughly mixed, placed in a metal can and a porous tea bag containing 2.0 grams boric anhydride was suspended therein and the can sealed up. The sample was of proper color, showing no reaction, after 6 days at raised temperatures. The unprotected check sample was black and badly caked after 6 days under the same temperature conditions.
Example 6 The formula of Example 5 was stabilized in the same manner except 2 grams of metaboric acid were placed in the tea bag. Similar results were obtained as in Example 5.
Example 7 The formula of Example 5 was placed in the sealed can and protected by a combination of 0.2 gram phthalic anhydride mixed with 1.8 grams of boric anhydride in a tea bag. The protected sample was of good whiteness after 6 days.
By our novel process many of the advantages of employing a boric anhydride stabilizer actually mixed in the single-powder developer, as shown in the copending application Serial No. 210,285, supra, can be attained by placing a closed bag of boric anhydride within the can of developer. As indicated similar stabilizing effects are attained by employing metaboric acid, phthalic anhydride-boric anhydride mixtures and metaboric acid-phthalic anhydride mixtures. This unexpected discovery permits single-powder mixtures having highly reactive ingredients to be stabilized against reaction without actually mixing the boric anhydride stabilizer throughout the developer powder. Hence the developer can be put into solution Without also actually adding the stabilizer to the solution.
1. The method of stabilizing a single-powder photographic developer composition containing an organic silver halide developer and a photographically compatible basic ingredient selected from the group consisting of alkali sulfites and carbonates which comprises packaging the developer composition in a closed container in which is positioned a closed permeable bag containing a stabilizer selected from the group consisting of boric anhydride, metaboric acid, and mixtures of boric anhydride with phthalic anhydride and mixtures of metaboric acid and phthalic anhydride.
2. The method of stabilizin a single-powder photographic developer composition containing an organic silver halide developer, an alkali carbonate, and an alkali sulfite which comprises packaging the developer composition in a closed container in which is positioned a closed permeable bag containing boric anhydride.
3. The method of stabilizing a single-powder photographic developer composition containing an organic silver halide developer, an anhydrous alkali sulfite, and an alkali carbonate which comprises packaging the developer composition in a closed container in which is positioned a closed permeable bag containing metaboric acid.
4. The method of stabilizing a single-powder photographic developer composition containing monomethyl p-ainino phenol sulfate, hydroquinone, anhydrous sodium sulfite, sodium carbonate monohydrate and potassium bromide which comprises packaging the developer com" position in a closed container in which is positioned a closed permeable bag containing substantially equal amounts of boric anhydride and phthalic anhydride.
5. The method of stabilizing a single-powder photographic developer composition containing monomethyl p-amino phenol sulfate, hydroquinone, anhydrous sodium sulfite, sodium carbonate and potassium bromide which comprises packaging the developer composition in a closed container in which is positioned a closed permeable bag containing metaboric acid and phthalic anhydride.
References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,591,899 Walker July 6, 1926 2,058,250 Nitardy Oct. 20, 1936 2,384,592 Bean Sept. 11, 1945 2,606,118 Rogers Aug. 5, 1952