US3615497A - Benzyl alcohol dispersions - Google Patents

Abstract

Aqueous dispersions of benzyl alcohol can be formed with emulsifying agents such as hydroxyethyl cellulose. Such dispersions are highly effective in forming photographic processing solutions.

Description

United States Patent [72] Inventors Henry Josef Fassbender Rochester; Roy James Kanous, Hilton, both of N.Y. [21] Appl. No. 743,917 [22] Filed July 11, 1968 [45] Patented Oct. 26, 1971 [7 3] Assignee Eastman Kodak Company Rochester, N.Y. Continuation-impart of application Ser. No. 702,205, Feb. 1, 1968.

[54] BENZYL ALCOHOL DISPERSIONS 2,875,049 2/1959 Kridel 96/66 2,945,761 7/1960 Weissberger 96/55 FOREIGN PATENTS 670,453 4/1952 GreatBritain 96/94 OTHER REFERENCES Cellosize Hydroxyethyl Cellulose, Union Carbide Corp, New York (1964), page 4 Davidson: Water-Soluble Resins (2nd Edition) Reinhold Book Corporation, New York 1968), page 63 Kirk-Othmer: Encyclopedia of Chemical Technology (2nd Edition), Vol. 3, B to Calcium, pages 444- 445 Primary Examiner-Norman G. Torchin Assistant Examiner-Won l-l. Louie, Jr.

Attorneys-Walter O. l-lodsdon, Paul R, Holmes and D. J.

Holter ABSTRACT: Aqueous dispersions of benzyl alcohol can be formed with emulsifying agents such as hydroxyethyl cellulose. Such dispersions are highly effective in forming photographic processing solutions.

RELATED APPLICATIONS This application is a continuation-in-part of Kanous and Fassbender, U.S. application Ser. No. 702,205 filed Feb. 1, 1968.

This invention relates to photographic processing solutions. ln one aspect this invention relates to photographic color developers and processes used in the production thereof, especially wherein the color developer components are prepackaged in solution form for ready mixing and use by the trade.

In the processing of photographic film and paper, wide varieties and large quantities of photographic developers are utilized. To facilitate the preparation and use of these developers, it has been found desirable to package the developers in liquid form usually as concentrates. However, some of the individual components of these developers, especially of color developers, react with one another and at the concentrations desired are not miscible. For these reasons the individual components have been conveniently packaged in separate compartments of.a single package. In the separate compartments, the essential ingredients are desirably either liquid per se or in solution so that mixing the ingredients into a complete developer involves little time-consuming dissolution. The separate compartments have, for example, respectively contained benzyl alcohol, base plus buffering ingredients, hydroxylamine sulfate, and an acidic solution of developing agent plus sulfite.

We have found that even though the packaged components are all liquid, the mixing times involved in assuring complete dissolution of the components in the ultimate developer were far in excess of that desired by the trade. The excess mixing time frequently involves undesirable shutdown time for the processing machine. Such difiiculty in assuring dissolution also often results in attempts to'utilize the developer before complete dissolution and thereby causes quality control problems and general inconsistency in processing characteristics. Since these difficulties result in substantial time loss and expense to both the processor and his customers and further result in dissatisfaction with the photographic reproductions, investigations were undertaken to seek methods and compositions which minimize the difficulties.

ln prepackaged photographic processing compositions, especially liquid concentrates having separate compartments for keeping various essential ingredients from interaction, it has been considered necessary to compartmentalize benzyl alcohol, which often is a desirable or necessary component of such compositions, separately. This was apparently done because of the failure of benzyl alcohol to dissolve at the high concentrations desired for liquid concentrates. We have unexpectedly found that even at the relatively low concentration in which benzyl alcohol is employed in conventional photographic processing solutions, e.g., color developers, the benzyl alcohol has such low solubility to cause unnecessary time delays in mixing the components to form the developer.

According to the present invention we have unexpectedly found compositions and methods which not only obviate the necessity of packaging benzyl alcohol separately from the other ingredients in liquid photographic processing concentrates, but also facilitate the dissolution of benzyl alcohol to form the ready-to-use processing solution, without detracting from the effectiveness'of the overall processing characteristics of the solution. We have found that stable, concentrated dispersions of benzyl alcohol in water are formed if the concentrated composition contains water-soluble polymeric carbohydrates or polymeric amides, especially cellulose-based emulsifying agents. We have further found that extremely stable dispersions of benzyl alcohol plus emulsifying agents in water are formed if the composition further contains ionic materials, for example, salts such as alkali metal sulfates,

sulfites, phosphates, borates, citrates, etc. or other substances which are necessary or desirable in the intended processing- .solution, such as hydroxylamine sulfate, etc. Surprisingly, the

maximum amount of such salts that can be incorporated into the compositions appears limited only by the solubility of the particular salt chosen. That is, although salts are not necessary to the formation of stable dispersions, very stable dispersions result even at high salt concentration. For example, a dispersion containing a water/cellulose-based emulsifying agent weight ration of about l/.00l to 0.01, a water/benzyl alcohol weight ration of about 1.1 to 25/1, and a water/salt ratio of 1/.00O1-0.33 presents a dispersion of outstanding stability. The benzyl alcohol may thus be incorporated into a compartment of the processing solution containing an aqueous solution of other processing, e.g., developer, components and can be packaged in plastic, e.g., polyethylene containers. The shipping, handling, and packaging costs for such processing compositions, therefore can be substantially decreased. Such compositions containing water, benzyl alcohol, arid the indicated emulsifying agents can also readily be diluted with more water and/or solutions containing other processing components with no appreciable oiling out of the benzyl alcohol and is found to substantially diminish the mixing time normally involved in combining separated components of liquid processing concentrates, especially in fonning color developers.

In accordance with the present invention it is especially desirable to utilize a water/emulsifying agent weight ratio of about l/.0020.0l. It is further desirable to maintain a water/benzyl alcohol weight ratio of about 1.1 to 25/1 in the dispersion. In a highly efficacious embodiment of this invention, salts, especially hydroxylamine sulfate, are also present such that the salt/water weight ration is about 0.01 -33/l00, but limited generally only by the solubility of the selected salt in aqueous solution. Such compositions are found to be resistant to separation as well as nonfoaming and have no appreciable detrimental effect when used in the desired photographic processing solution, e.g., color developers. The minimum amount of cellulose-based emulsifier necessary may vary somewhat depending, inter alia, upon the particular emulsification a'gent(s) selected, the amount of water present and the amount and type of other components present, but there is desirably sufficient emulsifying agent to maintain a stable suspension of benzyl alcohol in the concentrate.

It will, of course, be understood that the stable dispersions described herein are those that are practically stable, i.e., dispersions which do not separate at all and those which do separate into apparently two or more layers on long standing but which readily redisperseupon a mere inversion of the container or at most with moderate agitation.

Water-soluble polymeric carbohydrate emulsifying agents and water-soluble polymeric amide emulsifying agents and water-soluble carbohydrate and polyamide'derivatives are the only compositions found which form stable dispersions of benzyl alcohol in water. Carbohydrate compositions which are effective are starch derivatives such as Ceron (Hercules Chemical Company), etc.; Guar gums, for example, carboxymethyl Guar, etc., and water-soluble cellulose-based emulsifying agents such as cellulose sulfates, cellulose acetate sulfates, low acetyl containing cellulose acetates, sodium algenate, sodium hydroxypropyl algenate, methyl cellulose ethyl cellulose phthalates, mixed ethers of cellulose, e.g., isopropylmethyl ethers, etc.; and hydroxyethyl cellulose compositions which result in dispersions of surprisingly outstanding effectiveness. Polymeric amides of high effectiveness are the proteins, e.g., soya protein, lecithin and especially gelatin and emulsifying agents which are water-soluble derivatives of gelatin, etc.

The silver halide developing agents especially useful in the developer compositions of the present invention are the pphenylenediamine color-developing agents well known in the art especially those forming nondiffusing dyes with phenolic and reactive methylene couplers. These developing agents include p-phenylenediamine and N,N-dialkyl-p-phenylenediamines wherein the alkyl groups or the aromatic nucleus may be substituted, for example: N ,N-diethyl-pphenylenediamine monohydrochloride, 2-amino5- diethylaminotoluene monohydrochloride, 4-amino-N-ethyl- N- [fi-methanesulfonarnidoethyl l-m-toluicline sesquisulfate monohydrate, 4-amino- S-methyl-N-ethyl-N- [ti-hydroxyethyl]-aniline sulfate, 4-amino- 3-(B-methylsulfonamidoethyl) -N,N -diethy1ani1ine hydrochloride, 4-amino- N,N -diethyl-3 -(N '-methyl- B-methylsufonamido) -ani1ine hydrochloride and similar color-developing agents disclosed in U.S. Pats. Nos. 2,552,241 and 2,566,271. Other useful pphenylenediamine developing agents are disclosed in J.A.C.S. 73, 3,100 -3,125, 1951). Especially effective p-phenylenediamines are those containing at least one alkylsulfonamidoalkyl substitutent attached to the aromatic nucleus or to an amino nitrogen.

It is important that in prepackaged color developers containing p-phenylenediamine developing agents the solution containing the developing agent be acidic to assist in the stabilization of the developing agent and also to keep the developing agent in solution. The pH is preferably less than about 4. However, the optimum pH will vary depending upon the particular developing agent in use, for example, when 4- amino-N,N-diethyl- 3-(N-methyl -B-methylsulfonamidethyl)-aniline hydrochloride is used, it is desirable that the solution have a pH less than 1 particularly to keep the developing agent in solution in a concentrate.

Other components can be prepackaged in the same compartment with the color-developing agents, for example, sulfite may be present in accordance with the disclosure of U.S. Pat. Ser. No. 676,623 filed Oct. 19, 1967, by Kanous and Bimmler and other substances useful in the color development reaction may be present, such as antifoggants, e.g., benzotriazole, development restrainers, e.g., bromide and auxiliary black and white developing agents, such as the 3- pyrazolidone silver halide developing agents, e.g., 4,4- dimethyll-phenyl- 3-pyrazolidone. However, it is usually desirable to only incorporate the sulfite and developing agents as a simply aqueous solution with or without added acid. The combined concentration of the sulfite and developing agent can vary widely. Since the developer package is designed for shipment and storage, it is usually desirable to utilize the highest concentration of ingredients which will readily stay in acidic solution. More dilute solutions can, of course, be utilized depending upon the individual circumstances.

Packaging the benzyl alcohol in aqueous solutions of specific emulsifying agents generally is advantageous in packaging any compositions which require or desirably contain compounds, such as benzyl alcohol, ultimately dispersed or dissolved in aqueous solution. Such packaging is significant in photographic silver halide developer packages especially those which are to be utilized with well-known color products having differently sensitized silver halide emulsion layers containing nondifiusing coupler compounds, for example, those having superposed on a support, blue-, green-, and red-sensitized emulsion layers containing yellow, magenta, and cyan dye-forming couplers, respectively. The advantages obtained according to the present invention will be appreciated in packaging developers for a wide variety of color photographic elements, i.e., multicolor systems containing superposed red, green, and blue light-sensitive silver halide emulsion layers containing a cyan-forming coupler (e.g., a phenolic compound), a magenta-forming coupler (e.g., a S-pyrazolone compound) and a yellowforming coupler (e.g., an open chain ketomethylene compound), respectively. Suitable nondiffusion couplers are disclosed in U.S. PatS. Nos. 2,956,876, 2,407,293, and 2,640,776.

The developer compositions when mixed and ready for use can and desirably do contain the usual amounts of developing agent, sulfite and alkali as disclosed generally in the .lelley et a1. U.S. Pat. No. 2,322,027. According to this invention, packaged developer components advantageously are separated to the extent that in compartments containing developing agents, the sulfite concentration and the pH is controlled as indicated in U.S. Pat. Ser. No. 676,623, mentioned above, with the benzyl alcohol dispersion included in one or more of the compartments. Other components which may form part of the mixed developer package, for example, additional sulfite, accelerators, complexing agents, buffers, e.g., citric acid-citrate, boric acid-borate, etc., are advantageously contained in the compartment containing the alkali, e.g., potassium hydroxide, although placing selected addenda in other or separate compartments may be desirable depending upon the particular ingredient chosen.

The packaged developer effectively may be a single package, for example, an outside container or cardboard box in which the developer components are compartmentalized. The compartments can be an integral part of the exterior packaging material but advantageously are, at least in part, merely bottles of, for example, glass and/or plastic enclosed in the outside container. The choice of sizes and shapes of the bottles which form the compartments can vary with the selected ingredients, concentrations desired, etc. Usually it is desirable to choose the bottle size, shape, etc. which will result in a total package of minimum size and weight to minimize shipping and storage costs. As a result, it may in some instances be desirable to place a single component type in a plurality of compartments, e.g., to conserve space.

Although satisfactory dispersions are achieved by combining the above-specified ingredients in nearly any order, in one highly advantageous embodiment of the present invention the concentrated dispersions are prepared by gradually adding an aqueous portion which contains the emulsifying agent and other desirable components as indicated above to the benzyl alcohol. Accordingly, it is desirable to form an aqueous portion containing water, the selected emulsifying agent, especially hydroxyethyl cellulose, and desirably a salt. The desired quantity of benzyl alcohol to be dispersed is placed in a container which is fitted with a suitable means for agitating the liquid, e.g., a mechanical stirrer. The aqueous portion is gradually added to the benzyl alcohol while the benzyl alcohol and the dispersion resulting from the gradual addition are agitated.

The most advantageous rate of addition of the aqueous portion to the benzyl alcohol will, of course, vary depending upon the quantities involved, the effectiveness of the agitating means,etc. It appears desirable to control the rate of addition and mixing apparatus such that the quantity of material added at each unit of time does not exceed the quantity of dispersion or dispersant. An addition of 2 volumes of aqueous portion to 1 volume benzyl alcohol can be efiected in 1 minute time at volumes of a few liters with standard laboratory stirrers. With larger volumes it appears desirable to extend the mixing time to as much as 15 minutes in part because of the difiiculty of stirring large quantities, practical pump capacities, etc. It is also desirable to agitate, for example, by stirring the mixture for one-quarter to 1 hour after the addition is complete to assure a highly effective dispersion.

The following examples are illustrative of the methods and compositions of our invention:

EXAMPLE 1 A stable dispersion of benzyl alcohol in water is prepared in the following manner:

50 mg. of Natrosol 250 H (a high-viscosity hydroxyethyl cellulose marketed by Hercules Chemical Company) is added to 20 ml. of water. The mixture is stirred for about 1 hour. To this solution 12.6 ml. of benzyl alcohol is added with stirring. After the addition is complete the mixture is vigorously stirred. The resulting dispersion appears stable at room temperature.

EXAMPLE 2 The dispersion of example 1 is utilized as component A of a four-component liquid color developer. The remaining components containing:

monohydrate are combined with the benzyl alcohol dispersion and sufficient water to make 1 liter of working solution. The solution appears completely homogeneous after only about one-half the time required for the dissolution of a similar developer devoid of hydroxyethyl cellulose. The solution functions effectively and consistently as a color developer for color print material having respectively superposed on a paper support, blue-, green-, and red-sensitized emulsion layers containing yellow, magenta, and cyan dye-forming couplers, respectively, which has been exposed to a test pattern.

EXAMPLE 3 A dispersion of benzyl alcohol in a salt solution is prepared as follows:

2.1 g. of hydroxylamine sulfate is dissolved in ml. of water. To another 10 ml. of water is added 50 mg. of hydroxyethyl cellulose (Natrosol 250 H). After a period of soaking and stirring for about 1 hour the hydroxyethyl cellulose completely dissolves in the water. The two solutions are mixed together and 12.6 ml. of benzyl alcohol is added with stirring. The mixture is then vigorously shaken.

The dispersion thus formed is stable for over 2 months at 120 F.

EXAMPLE 4 A dispersion of benzyl alcohol in salt solution is prepared as follows:

2.l g. of hydroxylamine sulfate is dissolved in ml. of water. To this solution is added 50 mg. of hydroxyethyl cellulose (Natrosol 250 B). After soaking and stirring for about 1 hour the hydroxyethyl cellulose dissolves in the salt solution. To this solution benzyl alcohol is added with rapid stirring.

The resultant dispersion is stable for over 2 months storage at 120 F.

EXAMPLE 5 The dispersion of example 3 is utilized as component A of a three-component liquid concentrate color developer. The remaining components containing:

B. Sodium hexametaphosphate 2.0 g.

Sodium carbonate monohydrate 26.8 g. Sodium bicarbonate 2.9 g. Potassium bromide 0.48 g. Sodium chloride 0.7 3. Water about 60.0 ml.

C. 'Color'developing agent 4.2 g. Sodium sulfite 2.1 g. Water about l3.0 cc.

-amino-N-ethyl-N-[B-methanesulfonamidoethyH-m-toluidine sesquisull'ate rnonohydrate are readily combined with the benzyl alcohol dispersion and sufficient water to make 1 liter of working developer. The developer appears completely homogeneous after about onehalf the time previously required for a composition containing no hydroxyethyl cellulose.

The developer functions effectively and consistently when utilized with photographic color print material as described above.

EXAMPLE 6 The procedure according to example 5 is followed except that the benzyl alcohol dispersion of example 4 is utilized in place of the dispersion of example 3. Comparable results are obtained.

EXAMPLE 7 A benzyl alcohol dispersion containing the following:

Water 20 cc. Hydroxylamine sulfate 2.l g. Natrosol 250 H 5.0 mg. Benzyl alcohol 12.6 cc.

is prepared according to the procedure of example 3. The dispersion is stable except that after a period the dispersion appears to separate into two layers. It is found that the dispersion is still stable but that the dispersed complexes of benzyl alcohol and emulsifying agent merely tend to be buoyant. Upon merely turning the container over, the dispersion appears homogeneous.

The dispersion functions effectively and is readily miscible with the photographic color developer components B and C listed in example 5.

EXAMPLE 8 A benzyl alcohol dispersion containing the following:

Water 20 cc. Hydroxylamine sulfate 2.! g. Natrosol 250 H 200.0 mg. Benzyl alcohol l2.6 cc.

is prepared according to the procedure of example 4. The dispersion, although somewhat thick, appears stable and functions effectively and easily mixes with the photographic developer components B and C listed in example 5.

EXAMPLE 9 A benzyl alcohol dispersion was prepared in the manner indicated in example 3 except that Natrosol H is utilized in place of Natrosol 250 H. Comparable results are obtained both as to the dispersion itself and its effectiveness in a developer.

EXAMPLE 10 A benzyl alcohol dispersion is prepared in the manner indicated in example 3 except that a moderately low-viscosity hydroxyethyl cellulose (Natrosol 250 G) is utilized in place of the higher viscosity analog. Comparable results are obtained both as to the dispersion itself and its effectiveness and ease of mixing with a photographic color developer.

EXAMPLE 1 l A benzyl alcohol dispersion is prepared according to the procedure outline in example 3 except that carboxyethyl Guar is utilized in place of the Natrosol. The dispersion appears stable for periods in excess of 1 week and functions well in photographic developers.

EXAMPLE 12 A benzyl alcohol dispersion is prepared according to the procedure outlined in example 3 except that gelatin is utilized in place of the Natrosol. The dispersion appears stable for periods in excess of 1 week and functions well in photographic developers.

EXAMPLE 13 A benzyl alcohol dispersion is prepared according to the procedure outlined in example 3 except that carboxymethyl cellulose is utilized in place of the Natrosol. The dispersion appears stable for periods in excess of l week and functions well in photographic developers.

,7 EXAMPLE 14 A benzyl alcohol dispersion is prepared according to the procedure outline in example 3 except that carboxymethyl hydroxyethyl cellulose is utilized in place of the Natrosol. The dispersion appears stable for periods in excess of 1 week and functions well in photographic developers.

EXAMPLE 15 A dispersion of water in benzyl alcohol is prepared in the following manner:

About 50 mg. hydroxyethyl cellulose (Natrosol 250 H) is soaked in about 19 g. water and stirred for about 1 hour. The resulting aqueous solution is slowly added to 13.3 g. benzyl alcohol with rapid stirring. The stirring is continued for about 30 minutes. The resultant milky dispersion is stable for periods in excess of 1 week.

EXAMPLE 16 The procedure according to example 15 is followed except that the water used for the dissolution of the hydroxyethyl cellulose contains about 3 g. hydroxylamine sulfate. The resultant dispersion is stable for periods in excess of 1 week.

EXAMPLE 17 The procedure to example 16 is followed except that Natrosol 250 M is utilized in place of 250 H. Similar results are obtained.

EXAMPLE 18 The procedure according to example 16 is followed except that the pH of the hydroxylamine sulfate is adjusted to approximateiy 4 before the addition to benzyl alcohol. Similar results are obtained and there is little or no yellowing of the benzyl alcohol dispersion even on long standing.

EXAMPLE 19 The dispersion of example 16 is utilized as component A of a three-component liquid concentrate photographic color developer. The remaining components contain:

-lfiimst flextevenii si ll -mfiw tness] monohydrate.

Part A is added to about 800 ml. of distilled water with stirring. Parts B and C are then added in that order. The quantity is then brought up to 1 liter by the addition of water. The developer functions effectively and consistently with photographic color print material as described above.

EXAMPLE 20 The procedure according to example 19 is followed except that about 2.8 g. ethylenediamine tetraacetic acid is included in Part B. Similar results are noted.

EXAMPLE 2 l The procedure according to example 19 is followed except that about 2.8 g. nitrolo triacetic acid is included in Part B. Similar results are noted.

EXAMPLE 22 The procedure according to example 19 is followed except that about 2.8 g. 1,3 -diamino-2-propanol tetraacetic acid is included in Part B. Similar results are noted.

EXAMPLE 23 The procedure according to example 19 is followed except that an equivalent amount of Z-amino- S-diethylaminotoluene monohydrochloride is utilized as the color-developing agent in Part C.

The invention has been described in considerable detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

We claim:

1. A stable composition of matter useful as a concentrate for preparing photographic developer solutions consisting essentially of 1) water, (2) benzyl alcohol, (3) at least one emulsifying agent selected from the group consisting of watersoluble polymeric carbohydrate emulsifying agents and watersoluble polymeric amide emulsifying agents and water-soluble emulsifying agent derivatives of polymeric carbohydrates and polymeric amides and (4) a stabilizing amount of at least one water-ionizable salt of the group consisting of sulfates, sulfites, phosphates, borates and citrates, in said composition the water/benzyl alcohol weight ration being about 1.1-25/l and the water/emulsifying agent weight ration being about l/0.0l 0.0002.

2. The stable composition of claim 1 wherein said polymeric carbohydrate emulsifying agent and derivatives thereof are selected from the group consisting of carboxymethyl Guar, cellulose sulfates, cellulose acetate sulfates, sodium algenate, sodium hydroxypropyl algenate, methyl ethyl cellulose phthalates, isopropylmethyl ethers, and hydroxyethyl cellulose compositions and said polymeric amide emulsifying agents and derivatives thereof are selected from the group consisting of soya protein, lecithin, gelatin and water-soluble derivatives of t n. 7

'3. The stable composition of matter of claim 2 wherein said watenionizable salt is hydroxylamine sulfate.

4. The stable composition of matter of claim 2 wherein said emulsifying agent is hydroxyethyl cellulose.

Claims (3)

1. 2. The stable composition of claim 1 wherein said polymeric carbohydrate emulsifying agent and derivatives thereof are selected from the group consisting of carboxymethyl Guar, cellulose sulfates, cellulose acetate sulfates, sodium algenate, sodium hydroxypropyl algenate, methyl ethyl cellulose phthalates, isopropylmethyl ethers, and hydroxyethyl cellulose compositions and said polymeric amide emulsifying agents and derivatives thereof are selected from the group consisting of soya protein, lecithin, gelatin and water-soluble derivatives of gelatin.
2. 3. The stable composition of matter of claim 2 wherein said water-ionizable salt is hydroxylamine sulfate.
3. 4. The stable composition of matter of claim 2 wherein said emulsifying agent is hydroxyethyl cellulose.