Dispersion Containing Nonionic Surface Acting Agent With Units Of Polyoxyethylene And Polyoxypropylene

Abstract

A dispersion comprising an aqueous medium having dispersed therein an oleophilic material in the presence of (a) a nonionic surface active agent containing polyoxypropylene units having a molecular weight of greater than 500 and polyoxyethylene units, and a molar ratio of said polyoxyethylene units to said polyoxypropylene units ranging from 0.1 to 0.6, and (b) an anionic surface active agent having an --OSO.sub.3 M group or an --SO.sub.3 M group, wherein M represents a monovalent cation, and a hydrophobic group is disclosed.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a dispersion of an oleophilic material in an aqueous medium and more specifically the invention relates to a novel dispersion useful for incorporating an oleophilic material such as oleophilic couplers for color photography, ultraviolet absorbents for color photography, etc., into silver halide photographic emulsions.

2. Description of the Prior Art

In general, it is well known that many surface active agents are effective for dispersing oil-soluble materials in water. In the dispersion obtained using such known systems, the size of the dispersed particles is usually larger than 2 microns in diameter. On the other hand, particularly in photographic emulsions, it is required that the particle size to be dispersed in an aqueous gelatin solution be less than at the most 0.5 micron and the surface areas of the particles be as large as possible.

That is to say, in the first place, because the many steps which are involved in the process of forming the dyes, such as the dissociation of the couplers, the diffusion of the oxidation product of a developing agent, the coupling reaction, the removal of elimination reaction products, etc., are conducted through the interfaces between these particles and gelatin gel, it is important for providing high coupling reactivity to the couplers to increase the surface area of the interfaces. It the second place, because the refractive index of the coupler particles or ultraviolet absorbent particles not only in a gelatin layer wetted by a processing solution but also in a dry gelatin layer is not, in general, equivalent to that of the gelatin in that layer, the particles of the coupler or the ultraviolet absorbent cause light scattering and make the gelatin layer opaque to some extent. Accordingly, in order that the emulsion layer containing the dye images has high transparency, it is necessary to reduce the size of the particles in the emulsion.

An oleophilic coupler or an oleophilic ultraviolet absorbent has, hitherto, been dispersed as fine droplets in an aqueous medium using an aqueous solution of gelatin as the aqueous medium and an anionic surface active agent as the emulsifying agent.

As example of such anionic surface active agent, there are described Gardinol WA (trade name of a sulfated coconut fatty alcohol, made by the E. I. Du Pont de Nemours Co.) and triisopropylnapthalene sulfate described in the specification of U.S. Pat. No. 2,332,027 and Alkanol B (sodium triisopropylnapthalene sulfate made by the E. I. Du Pont de Nemours Co.) in the specifications of U.S. Pat. No. 2,801,170 and U.S. Pat. No. 2,801,171. Furthermore, in the specification of Japanese Pat. No. 428,191, a method of using as an emulsifying agent a water soluble coupler having a sulfo group or a carboxyl group together with an aliphatic group having the same chain length is described.

In fact, it has been possible to disperse mechanically an oleophilic coupler or an oleophilic ultraviolet absorbent as fine particles thereof to some extent using the above-described combination of gelatin and the anionic surface active agent. However, the emulsification step for this combination is accompanied with great difficulties. That is to say, the combination of gelatin and the anionic surface active agent is accompanied with the difficulties that the emulsion foams, the emulsifying efficiency is reduced by the foaming, and the increase in the amount of the anionic surface active agent necessary makes the coating of the photographic emulsion in the subsequent step difficult. An aqueous gelatin solution containing an anionic surface active agent tends to foam quite readily to such an extent that the entire solution can be foamed by stirring the solution vigorously. Thus, if such a readily foamable solution is stirred to achieve dispersion by emulsification, a large amount of foam is formed in the solution. The shearing stress provided by the means used for emulsification is lost due to the foam cushioning thereby disturbing the effective transmission of the shearing stress to the oil droplets containing the coupler. This results in greatly reducing the emulsification efficiency. Also, the fine foam formed in the emulsified liquid in the emulsification step partially remain in the coating solution, which causes pin holes in the emulsion layer thus coated using such a coating solution. Furthermore, in order to emulsify finely a coupler to a satisfactory extent, it is necessary to use a large amount of an anionic surface active agent but when a photographic emulsion containing a large amount of an anionic surface active agent for emulsification is coated on a support as a layer of a multi-layer systems used for color photographic light-sensitive materials, not only the emulsion layer but also other subsidiary gelatin layers tend to have a great unevenness in thickness of the coated layers, which prevents the production of light-sensitive materials of uniform qualities.

On the other hand, if a water-soluble nonionic surface active agent or amphoteric surface active agent, each of which has a polyoxyethylene group and each of which is a surface active agent which is well known to be useful for dispersing by emulsification an oily material in water, is used together with gelatin, it is difficult to disperse finely a coupler therein to a sufficient extent. Furthermore, when a cationic surface active agent is used together with gelatin, a coupler may be emulsified to a considerable extent immediately after emulsification but the particles of the coupler aggregate to form massive particles with the passage of time and finally complete emulsion breakage occurs. In other words, the emulsified dispersion of a coupler, etc., by using the combination of a cationic surface active agent and gelatin is poor in stability with the passage of time.

Moreover, when the emulsified dispersion prepared using a cationic surface active agent is added to a silver halide emulsion, the photographic properties are reduced due to the occurrence of fogs in the photographic emulsion and weak bleaching and also the mechanical strength of the emulsion layer constituting the multilayer system used for color photographic light-sensitive materials is reduced.

A few cases have been reported on specific emulsifying techniques and among these known methods, a method of dispersing by emulsification a coupler in an aqueous medium containing gelatin in the presence of at least a sulfonic acid-type or a sulfuric acid ester-type anionic surface active agent and at least one nonionic surface active agent of a sorbitan fatty acid ester type is known as an effective technique for dispersing couplers by emulsification (Belgian Pat. No. 737,133). However, when such a known method is used to incorporate by heating a water-soluble ultraviolet absorbent of an .alpha.-cyanocinnamic acid ester type in an organic solvent such as dibutyl phthalate and tricresyl phosphate, the .alpha.-cyanocinnamic acid ester type ultraviolet absorbent once dissolved deposits in the solution.

As described above, many of the generally known techniques of emulsification dispersion presently are not suitable.

An object of this invention is, therefore, to provide a dispersion having improved physical and photographic properties, such as a dispersion in which an oleophilic material has been dispersed finely in an aqueous medium and in which the resulting dispersion is stable.

A further object of the present invention is to provide a photographic material having excellent properties prepared by using the above-described dispersion (for instance, a color photographic material which is stable for a long period of time and shows a high coupling activity).

SUMMARY OF THE INVENTION

The above objects of the present invention can be attained by dispersing an oleophilic material in an aqueous medium in the presence of (1) at least one nonionic surface active agent containing in the molecule thereof polyoxypropylene units and polyoxyethylene units in which a molecular weight of the polyoxypropylene units is greater than 500, the molar ratio of the polyoxyethylene units to the polyoxypropylene units being from 0.1 to 0.6 and (2) at least one anionic surface active agent having in the molecule thereof a hydrophobic hydrocarbon group and containing an --SO.sub.3 M group or an --OSO.sub.3 M group, wherein M represents a monovalent cation.

DETAILED DESCRIPTION OF THE INVENTION

In practice, it is preferable to disperse in an aqueous mediun an oleophilic material per se or a solution thereof in an organic solvent in the presence of at least one nonionic surface active agent as described above and at least one anionic surface active agent as described above. The term "in the presence of" means that the both surface active agents are present, separately or in combination, in at least one of the oleophilic material, the organic solvent and the aqueous medium on the dispersing of the oleophilic material.

Furthermore, a photographic light-sensitive material can also be produced by adding the dispersion prepared in the manner as described above in a silver halide photographic emulsion and coating the emulsion on a support using techniques well known in the photographic field.

The anionic surface active agent and the nonionic surface active agent as described above can be incorporated in the oleophilic materials per se, solutions thereof, e.g., the coupler solution, the ultraviolet absorbent solution, and the aqueous solution of the hydrophilic materials described above, or in combination thereof.

The anionic surface active agents which are suitable for the practice of this invention are an amphiphilic substance having an appropriate hydrophilic group and a hydrophobic group in the molecule and can be selected from a wide range of compounds, each having an --SO.sub.3 M group or --OSO.sub.3 M group, where M is a monovalent cation, for example, a hydrogen atom, an alkali metal such as Na, K and Li, or an ammonium group such as NH.sub.4, and a hydrophobic hydrocarbon group, preferably having about 8 to about 30 carbon atoms. Those anionic surface active agents are illustrated in Ryohei Oda and Kazuhiro Teramura Synthesis and Application of Surface Active Agent and A. W. Schwartz and J. W. Perry Surface Active Agents (Interscience Publication).

The term "anionic surface active agent" used in the present invention includes not only commonly used so-called anionic surface active agents as described above but also a water-soluble coupler which has a hydrophobic group, preferably hydrocarbon radical of about 8 to about 30 carbon atoms and an --SO.sub.3 M group, where M is as above defined, as generally used in a photographic field.

Specific examples of the particularly useful anionic surface active agents used in this invention are shown below: ##SPC1##

The nonionic surface active agent which can be used in this invention is composed of a polyoxypropylene fragment with a molecular weight of greater than 500 and a polyoxyethylene fragment, in which a molar ratio of the entire polyoxyethylene units to the entire polyoxypropylene units ranges from 0.1 to 0.6. The term, "fragment" used hereinafter has the same meaning as "units."

When the polyoxypropylene fragment has a considerably higher molecular weight, the amount of the polyoxyethylene fragment can be increased so as to control the physical properties of the nonionic surface active agent. Therefore, any nonionic surface active agent having a wide range of a molecular weight can be used. When a polyoxypropylene fragment of a nonionic surface active agent, has a molecular weight of less than 500 is used, the resulting dispersion is unstable. The nonionic surface active agent has the entire molecular weight, preferably up to about 8,000 and more preferably having a molecular weight of from 1,000 to 5,000.

Specific examples of the nonionic surface active agents particularly suitable for the practice of this invention are illustrated below, although the nonionic surface active agent used in this invention are not limited to these examples only. ##SPC2##

Some of the above compounds are believed to be commercially available under the trade names of New Pole TL-4500, New Pole GEP-2800, New Pole SP-750 made by the Sanyo Chemical Industry Co., Ltd. Pluronic L-61, Pluronic L-62, Pluronic L-44 made by the Wyandotte Chemical Corp., etc.

The nonionic surface active agents of this type can be prepared by methods described in various known literature and by changing the ratio of polyoxypropylene and polyoxyethylene, the compound having a suitable HLB (hydrophile - lypophile balance) value for use can be readily obtained.

The oleophilic coupler to be incorporated in a photographic emulsion utilizing the dispersion of this invention is a colorless or colored compound having a coupling unit capable of giving a colored compound having a spectral absorption in a visible wave length region by the coupling reaction with the oxidation product of an N,N-di-substituted p-phenylenediamine compound together with a hydrophobic group having from 9 to 28 carbon atoms as an oil solubilizing group. This coupler has no group such as sulfonate group or a sulfuric acid ester group which is excessively hydrophilic.

The coupling unit of the aforesaid oleophilic coupler can be selected from the phenols and compounds having aromatic groups, amines, pyrroles, or active methylene groups. In particular, a phenol derivative, a napthol derivative, an acylacetanilide derivative, and a 5-pyrazolone derivative are useful as such a coupling unit.

Examples of the oil-soluble or oleophilic couplers suitable for the practice of this invention are described together with the production methods thereof in the specifications of U.S. Pat. Nos. 2,322,027, 2,455,170, 2,600,788, 2,801,170, 2,908,573, 3,062,653, 3,148,062, 3,227,551, 3,227,554, 3,337,344, 3,418,129, 3,516,831, 3,519,429, 3,558,700, 3,583,971 and 3,617,291. More particularly speaking, the yellow-forming couplers are illustrated in the specifications of U.S. Pat. Nos. 3,265,506, 3,409,439, 3,551,155, 3,551,156 and 3,582,322; U.S. Patent Application Ser. No. 235,937 filed on Mar. 3, 1972; and Japanese Patent Application No. 3039/1972; the cyan-forming couplers are illustrated in the specifications of U.S. Pat. Nos. 2,474,293 and 3,591,383; and Japanese Patent Publication Nos. 11302/1967 and 27563/1964; the magenta-forming couplers are illustrated in the specifications of U.S. Pat. Nos. 2,373,821, 2,899,443, 3,127,269, 3,468,666, 3,558,319 and 3,582,322; U.S. Patent application Ser. No. 199,337 filed on Nov. 16, 1971; and Belgian Pat. No. 697,112; the colored couplers are illustrated in the specifications of U.S. Pat. Nos. 3,034,892, 3,459,552, 3,481,714, 3,459,552, and 3,583,971; and the couplers having absorption spectrum at an infra-red region and illustrated in the specifications of U.S. Pat. Nos. 2,530,349 and 2,545,687; and Japanese Patent Application No. 94265/1971.

Specific examples of these couplers are illustrated below: ##SPC3##

Examples of the oleophilic ultraviolet absorbents suitable for the practice of this invention are described, for example, in U.S. Pat. Nos. 2,739,888, 2,784,087 and 3,352,681; (a thiazolidone derivative): U.S. Pat. Nos. 3,253,921 and 3,533,794, German Offenlegungsschrift (OLS) No. 2,151,098 (corresponding to U.S. Pat. application Ser. No. 189,013 filed on Oct. 13, 1971) and Japanese Patent Publication OPI No. 1026/1972 (a 2-phenyl benzotriazole derivative); German Offenlegungsschrift (OLS) No. 2,049,289 (corresponding to U.S. Pat. application Ser. No. 78,710 filed on Oct. 7, 1970) (an .alpha.-cyanocinnamic acid ester); German Patent Publication (DAS) No. 1,087,902; and U.S. Pat. Nos. 2,685,512 and 3,250,617.

Several specific examples of the oleophilic ultraviolet absorbents suitably used in the present invention are illustrated below: ##SPC4##

The above ultraviolet absorbents can be used together if desired, e.g., as a combination of an .alpha.-cyanocinnamic acid ester and a 2-phenylbenzotriazole. Some of a 2-phenylbenzotriazole type absorbent are commercially available under the trade name of Tinuvin, made by Geigy A. G. in West Germany.

Further examples of the oleophilic materials used in the dispersion system of the present invention are antioxidants, dye image stabilizing agents, fluorescent brightening agents, dyes for silver dye bleaching process, leuco dyes or color formers for pressure sensitive copying sheet which are all oil-soluble or oleophilic as commonly used in the photographic field. Specific examples of these oleophilic materials are described, for example, in the following specifications:

i. antioxidants: U.S. Pat. Nos. 2,336,327 and 2,360,290; German Offenlegungsschrift (OLS) Nos. 2,110,521 (corresponding to U.S. Pat. application Ser. No. 17,730 filed on Mar. 6, 1970 and 2,149,789; ii. dye image stabilizing agents: U.S. Pat. Nos. 3,432,300, 3,573,050 and 3,574,627; OLS Nos. 2,126,187; 2,126,954, 2,140,309 (corresponding to U.S. Pat. application Ser. No. 63,270 filed on Aug. 12, 1970) and 2,146,668 (corresponding to U.S. Pat. application Ser. No. 182,558 filed on Sept. 21, 1971); U.S. Pat. application Ser. No. 213,540 filed on Dec. 29, 1971; and British Pat. No. 1,267,287; iii. fluorescent brightening agents: U.S. Pat. No. 3,630,738; iv. dyes for a silver dye bleaching process: U.S. Pat. No. 3,651,494; v. leuco dyes or color formers for pressure sensitive copying sheet: U.S. Pat. Nos. 2,800,457 and 3,432,327.

In the present invention, a liquid oleophilic material can directly be dispersed into an aqueous medium, and a solid oleophilic material can preferably be dissolved prior to the dispersion with heating or in an organic solvent to render it liquid. When an oleophilic material having a melting point below that of water is dissolved with heating, it is expedient to conduct this dissolution under a mild condition.

The organic solvent for oleophilic materials used for dispersing finely the oleophilic material in an aqueous medium is advantageously such a solvent as conventionally used for dissolving couplers in a gelatin containing medium, which is illustrated, e.g., in U.S. Pat. Pat. Nos. 2,322,027 and 3,253,921.

More specifically, the organic solvent of the above type which is substantially water-immiscible and has a boiling point of higher than about 175.degree.C at normal pressure can be selected from carboxylic acid esters, phosphoric acid esters, carboxylic amides, ethers, carbonates, ketones, sulfonamides and substituted hydrocarbons. Specific examples of such organic solvents are di-n-butyl phthalate, di-iso-octyl phthalate, di-methoxyethyl phthalate, tricresyl phthalate, benzyl phthalate, di-n-butyl adipate, di-iso-octyl azelate, tri-n-butyl citrate, butyl laurate, di-n-butyl sebacate, tricresyl phosphate, tri-n-butyl phosphate, tri-iso-octyl phosphate, triphenyl phosphate, diphenyl mono-p-tert-butyl phenyl phosphate, mono-o-chlorophenyl phosphate, N, N-diethylcaprylic amide, N, N-dimethylpalmitic amide, n-butyl m-pentadecylphenyl ether, ethyl 2,4-tertbutylphenyl ether, and chlorinated paraffin.

In addition to the above described organic solvents, a hydrophobic liquid which is mixed with an oleophilic material and is dispersed in an aqueous medium can also be used. Examples of the hydrophobic liquid includes, castor oils, arachic oil, whale oil, turpentine oil, lard, dynamo oil, spindle oil, silicone oil, etc.

Among those organic solvents, di-n-butyl phthalate, tri-cresyl phthalate, tricresyl phosphate, dichlorodiphenyl and chlorinated paraffin are particularly preferred.

It is sometimes advantageous in the present invention to use a low-boiling solvent or a water-miscible solvent with or in addition to the above-described organic solvents for dissolving the oloephilic materials. The organic solvents are disclosed in U.S. Pat. Nos. 3,253,921 and 3,574,627. Examples of such solvents include:

1. Low-boiling solvents, such as propylene carbonate, methyl, ethyl, propyl, isopropyl and butyl acetates, ethyl propionate, nitromethane, nitroethane, chloroform, carbon tetrachloride, sec-butyl alcohol, etc. and

2. Water-miscible solvents, such as tetrahydrofuran, cyclohexanone, dimethylformamide, diethyl sulfoxide, methyl cellosolve, methyl isobutyl ketone, diethylene glycol monoacetate, acetonyl acetone, ethylene glycol, acetone, methanol, ethanol, and the like.

The aqueous medium which can be used in this invention can be selected from aqueous solutions containing hydrophilic colloid materials, such as gelatin, albumin, collodion, gum arabic, agar-agar, alginic acid, cellulose derivatives (e.g., the alkyl esters of carboxylated cellulose, hydroxyethyl cellulose, carboxymethyl hydroxyethyl cellulose, etc.), synthetic resins (e.g., polyvinyl alcohol, polyvinyl pyrrolidone, etc.) and others well known in the art.

The term "gelatin" used in the present invention includes an acid-treated gelatin, a lime-treated gelatin, an enzyme-treated gelatin and gelatin derivatives modified with an agent such as an acylating agent, e.g., acetylated gelatin, phthalated gelatin, succinated gelatin, etc. The hydrophilic colloid materials having higher molecular weight are suitable especially for preparing a finer dispersion, since such a property as a protective layer is enhanced as a molecular weight increases. A gelatin having an average molecular weight more than 30,000 is particularly effective.

These hydrophilic colloid materials can be used either alone or in combination.

As the dispersing means used for practicing the present invention, suitably there can be used any means which is capable of giving a large shearing force to the liquid to be treated or giving rise to high ultrasonic energy. Among these various means, a colloid mill, a homogenizer, a capillary-type emulsifying means, a liquid siren, an electromagnetic striction type sonic wave generator, an emulsifying means equipped with a Pohleman whistle, etc., give better results.

The amounts added of the anionic active agent and the nonionic surface active agent used in the practice of this invention depend upon the nature of the oleophilic materials used, the kind and amount of the solvent for dispersion, and the type of color photographic light-sensitive material prepared, but an especially effective amount of them ranges from 0.5 to 50 wt.% based on the weight of the oleophilic materials used, and preferably from 5 to 40 wt.% to give the most effective result. In general, the amounts added of the anionic surface active agent and the nonionic surface active agent are preferably equivalent. The anionic surface active agent was found to have a tendency of improving finely dispersing an oleophilic material when added in a small amount such as 0.2 wt. %, while the nonionic surface active agent was found to have a tendency to improve the storage stability of the resulting dispersion when added in an amount more than 1 wt.%. Both of these anionic surface active agent and nonionic surface active agent give a synergistic effect when used in combination and the amounts described above are not critical.

The present invention has the following effects and advantages.

That is to say, by using the aforesaid nonionic surface active agent and anionic surface active agent as described above according to the present invention, the oleophilic materials can be dispersed finely by emulsification in a photographic emulsion without reducing the photographic properties and, further, by using the emulsified dispersion thus prepared, excellent photographic light-sensitive materials can be obtained.

The nonionic surface active agent used in this invention contributes to minimize remarkably the formation of bubbles and foam in the dispersion and an anionic surface active agent and to facilitate the dispersion process. This fact will be clearly confirmed by the experimental results of Example 3 described hereinafter.

By using the nonionic surface active agent of this type, it becomes possible to disperse oleophilic materials as finer particles. This is believed to be due to, in addition to the above-described increase in the efficiency of dispersion by the reduction in the formation of foam, the reduction in the surface tension between the oil phase and aqueous phase to a quite low level by the co-operation of the hydrophilic material, the anionic surface active agent, and the nonionic surface active agent. The fact that fine dispersed particles are formed by the use of the nonionic surface active agent of this type will become clear from the results of the examples of this invention shown hereinafter.

Because the dispersion of oleophilic materials can be facilitated by the present invention, the amount of the anionic surface active agent used in the dispersion of these materials can be reduced. If a large proportion of an anionic surface active agent is present in a photographic emulsion at the coating thereof, the surface tension of the coating liquid is extremely reduced and thus when two or more photographic emulsions are coated simultaneously, the coatings tend to become uneven in thickness. On the other hand, because the amount of the anionic surface active agent in the present invention is less, the multilayer coating for color photographic light-sensitive materials can be uniformly and easily practiced.

Furthermore, because the nonionic surface active agent used in this invention is slightly soluble in water and has a low HLB value, the photographic emulsion containing the surface active agent has less foaming tendency and the stability of the emulsified dispersion is improved. However, when the nonionic surface active agent is incorporated alone in a photographic emulsion and the photographic emulsion is coated on a support, the coating liquid tends to be repelled on the support, is not easily spread over the surface of the support, and thus uneven coatings are obtained.

Thus, by the combination of the anionic surface active agent and the nonionic surface active agent in the dispersion system of this invention, a fine degree of dispersion and a uniform coating can be attained simultaneously.

As described above, the advantage of using the nonionic surface active agent and the anionic surface active agent in accordance with the present invention would not have been expected or anticipated from the nature or the effect of each of the surface active agents alone.

The present invention now will be explained in greater detail by reference to the following Examples.

EXAMPLE 1

A solution prepared in heating to about 50.degree.C a mixture of 10 g of the above-described ultraviolet absorbent U-1, 0.5 g of the above-described nonionic surface active agent N-1, 20 ml of dibutyl phthalate, and 15 ml of ethyl acetate was poured in 100 ml of an aqueous 10% gelatin solution containing 0.4 g of sodium dodecylsulfate (A-1) with stirring and dispersed by stirring for about 5 minutes in a high speed rotary mixer at 10,000 r.p.m.

Using an electron microscope the mean particle size of the ultraviolet absorbent in the dispersion was confirmed to be about 0.28 micron and the ultraviolet absorbent was confirmed to be dispersed therein as fine oil drops. In addition, when the nonionic surface active agent in this invention was not added to the dispersion, the mean particle size of the ultraviolet absorbent in the dispersion prepared in the same manner as described above was about 0.8 micron.

EXAMPLE 2

Two parts of a solution each containing 3 g of the above-described ultraviolet absorbent U-1, 3 g of the ultraviolet absorbent U-5, 6 g of the ultraviolet absorbent U-7, 20 ml of dibutyl phthalate, and 10 ml of ethyl acetate were prepared and after adding 0.5 g of the nonionic surface active agent N-2 described above and 0.5 g of a known or conventional oil-soluble nonionic surface active agent, sorbitan monolaurate, respectively, to each solution, each solution was heated to about 50.degree.C and allowed to stand for 30 minutes. Each solution was poured in 100 ml of an aqueous 10% gelatin solution containing 0.4g of sodium dodecylbenzene sulfonate A-12 and the mixture was dispersed by stirring it for 5 minutes using a high speed rotary mixer at 10,000 r.p.m. Thus, two kinds of dispersion were prepared.

The results obtained were as follows; that is to say, when the mixture of sorbitan monolaurate, the ultraviolet absorbent U-1, the ultraviolet absorbent U-5, the ultraviolet absorbent U-7, dibutyl phthalate, and ethyl acetate was heated to 50.degree.C, the mixture immediately became a completely transparent solution but when the solution was allowed to stand for 30 minutes at 50.degree.C, crystals again were formed. Furthermore, when the temperature of the system was raised to 60.degree.C, the crystals were not re-dissolved. On the other hand, for the mixture containing the nonionic surface active agent of this invention (N-2) no crystals formed and the mixture retained its transparency when it was allowed to stand for 30 minutes. When the mean particle size of each of the dispersion prepared above was measured using an electron microscope, coarse particles of 50 microns were observed among particles of 0.65 micron in the dispersion containing the conventional nonionic surface active agent, sorbitan monolaurate, while the mean particle size of the dispersion containing the nonionic surface active agent of this invention was about 0.3 micron, there were no particles of greater than one micron, and the ultraviolet absorbents in the dispersion were dispersed very finely. Also when the dispersion containing the nonionic surface active agent of this invention was allowed to stand in a cooling box for 20 days at 7.degree.C, the mean particle size was observed to be 0.3 micron, which showed the maintenance of stable dispersed condition.

EXAMPLE 3

A solution prepared by heating to 60.degree.C a mixture of 20 g of the above-described cyan-forming coupler C-2, 40 ml of di-n-butyl phthalate, and the above-described nonionic surface active agent N-1 in the amount shown in Table 1 was poured in 200 ml of an aqueous solution containing 15 g of gelatin and 2.0 g of sodium dodecylbenzene sulfonate (A-12) maintained at 60.degree.C and the mixture was dispersed by stirring it for 0 minutes using a high speed agitator at 2,000 r.p.m.

The entire amount of the dispersion prepared was allowed to stand for 10 minutes in a graduated cylinder and the apparent volume of the dispersion with foam was measured, the results of which are shown in Table 1.

TABLE 1 ______________________________________ Amount of Nonionic 0 0.4 0.8 1.6 Surface Active Agent (g) Total Volume of above 500 350 290 270 Dispersion (ml) ______________________________________

The above results confirmed the following. In the dispersion which did not contain the nonionic surface active agent N-1, the dispersion foamed greatly, the entire dispersion contained foam to such extent that the dispersion portion became indistinguishable from the foam portion, and thus a defoaming procedure became inevitable prior to the coating of the dispersion on the support. On the other hand, the dispersion containing more than 0.8 g of the nonionic surface active agent showed almost no foaming and thus when the dispersion immediately after dispersing was added to a photographic emulsion and the latter was coated on a support, an emulsion layer having no pin holes could be obtained.

Then, the above experiment was repeated while varying the amount of the anionic surface active agent A-12, each of the dispersions thus prepared was diluted with water, and the turbidity of the diluted dispersion was measured. From the wave length dependence of the turbidity, the mean particle size was obtained, the results of which are shown in Table 2 with the use of sorbitan monolaurate (the compound described in the specification of French Pat. No. 2,016,225) also being described for the purposes of comparison.

TABLE 2 ______________________________________ (Particle Size (.mu.) of Coupler Particles) Amount of Sorbi- Amount of N-1 tan Monolaurate ______________________________________ (g) (g) (A) 0 0.4 0.8 1.6 0.8 ______________________________________ (i) (ii) (iii) (iv) (xvii) 0.5 0.67 0.48 0.42 0.32 0.44 (v) (vi) (vii) (viii) (xviii) 1.0 0.45 0.35 0.32 0.28 0.32 (ix) (x) (xi) (xii) (xix) 1.5 0.37 0.28 0.21 0.19 0.23 (xiii) (xiv) (xv) (xvi) (xx) 2.0 0.30 0.21 0.19 0.19 0.19 ______________________________________ (A): Amount in grams (g) of the anionic surface active agent A-12. ?

In the dispersion (vii) and the dispersion (xiii) shown in Table 2, the coupler was dispersed as particles of almost same particle size. Also, the coupler was dispersed in both dispersions almost the same as employing sorbitan monolaurate. However, the amount of the anionic surface active agent in the dispersion (xiii) was twice as large as that in the dispersion (vii). By using both dispersions the following color photographic emulsions were prepared.

______________________________________ Red-sensitive Silver Halide 500 g Emulsion (containing 0.18 mole of silver chloride and 35 g of gelatin) Coupler Dispersion 175 ml Water 150 ml ______________________________________

When the coupler dispersion (xiii) was added, the surface tension of the silver halide emulsion was reduced to 34 dyne/cm, while when the coupler dispersion (vii) was added, the surface tension of the silver halide emulsion was 40 dyne/cm. Each of the two kinds of silver halide emulsions was coated on a triacetyl cellulose film base as a first layer followed by gelling by cooling and then an aqueous solution containing 0.25 g of saponin and 2.0 g of gelatin per 100 ml of the solution was coated on the layer at 30.degree.C and at a speed of 10 meters/min.

In those cases, the aqueous gelatin solution as the second coating could be coated uniformly over the surface of the silver halide emulsion containing the dispersion (vii), while the aqueous gelatin solution was partially repelled on the surface of the silver halide emulsion layer containing the dispersion (xiii) and could not be uniformly coated on the layer.

As illustrated above, by using the nonionic surface active agent according to the present invention, not only could the coupler be finely dispersed but also the coating of a silver halide emulsion containing the emulsified dispersion of the coupler could be facilitated.

EXAMPLE 4

The following three kinds of coupler dispersion were prepared.

(Dispersion a)

A coupler solution prepared by heating a mixture of 10 g of the above-described cyan-forming coupler C-2, 0.5 g of the above described nonionic surface active agent N-2, 20 ml of tri-o-cresyl phosphate, and 14 ml of ethyl acetate was poured with stirring into 100 ml of an aqueous 10 wt. % gelatin solution containing 0.4 g of the above-described sodium dodecylbenzene sulfonate A-12 and the mixture was dispersed by stirring for 5 minutes using a high speed rotary mixer.

(Dispersion b)

A solution prepared by heating a mixture of 10 g of the above-described magenta-forming coupler M-5, 0.5 g of the above-described nonoinic surface active agent N-4, 30 ml of tri-o-cresyl phosphate, and 10 ml of ethyl acetate was added to 100 ml of an aqueous solution containing 0.7 g of the anionic surface active agent A-9 and 7 g of gelatin at 60.degree.C and the mixture was dispersed with stirring for 10 minutes in a high speed mixer.

(Dispersion c)

A solution prepared by heating to 65.degree.C a mixture of 15 g of the above-described yellow-forming coupler Y-5, 0.5 g of the above-described nonionic surface active agent N-4, 20 ml of di-n-butyl phthalate, and 30 ml of ethyl acetate was added to 300 ml of an aqueous solution containing 25 g of gelatin and 0.5 g of the yellow-forming coupler having a sulfo group at 60.degree.C and the mixture was mechanically stirred vigorously for 30 minutes using a homogenizer.

It was confirmed using an electron microscope that the coupler had been dispersed together with the solvent as fine oil drops having a particle size of 0.1-0.4 microns in each of the three kinds of coupler dispersions prepared above. Furthermore, these dispersions were stable and neither the coagualtion of the colloid particles nor the growth of particles nor the crystallization of the coupler were observed.

The entire amount of the dispersion (a) prepared as described above was added to 360 g of a red-sensitive emulsion containing 0.11 mole of silver iodobromide and 18 g of gelatin; the entire amount of the dispersion (b) was added to 540 g of a green-sensitive emulsion containing 0.22 mole of silver iodobromide and 45 g of gelatin; and further the entire amount of the dispersion (c) was added to 500 g of a blue-sensitive emulsion containing 0.18 mole of silver iodobromide and 50 g of gelatin.

An aqueous gelatin solution containing black colloidal silver was coated on a triacetyl cellulose film base in the dry thickness of 3 microns, the above-described red-sensitive emulsion was coated on the gelatin layer in a dry thickness of 4 microns, an aqueous gelatin solution containing low-sensitive silver chlorobromide particles was coated on the red-sensitive emulsion layer in a thickness of 1.5 microns as an intermediate layer, the above-described green-sensitive emulsion was further coated on the intermediate layer in a thickness of 4 microns, an aqueous gelatin solution containing yellow colloidal silver was further coated on the green-sensitive layer in a thickness of 2 microns as a yellow filter layer, the above described blue-sensitive emulsion was coated on the filter layer in a thickness of 6 microns, and finally an aqueous gelatin solution was coated on the blue-sensitive layer in a thickness of 1 micron to give a color photographic negative film. In this case triethylene phosphamide was used as the hardening agent for the gelatin.

When the color photographic film thus prepared was exposed and processed as shown below, a color negative having sharp colors and high transparency was obtained.

______________________________________ Color Developing Processings: Process Temperature Time ______________________________________ Color Development 21.degree.C 14 min. Water Washing 18.degree.C 1 min. First Fixing 21.degree.C 4 min. Water Washing 18.degree.C 3 min. Bleaching 21.degree.C 3 min. Water Washing 18.degree.C 2 min. Second Fixing 21.degree.C 3 min. Water Washing 18.degree.C 20 min. ______________________________________

The composition for the color developing solution used in the above color development was as follows:

Color Developing Solution ______________________________________ Water 1 liter Benzyl Alcohol 4.0 ml Sodium Hexametaphosphate 2.0 g Anhydrous Sodium Sulfite 2.0 g 4-Amino-N-ethyl-N-(.beta.-methanesulfone- 5.0 g amidoethyl)-m-toluidine.sesquisulfate Postassium Bromide 1.0 g Sodium Carbonate.monohydrate 4.0 g ______________________________________

Also, an acid aqueous solution containing sodium thiosuflate and sodium sulfite was used as the fixing solution and a neutral aqueous solution containing potassium ferricyanide was used as the bleaching solution in the above procedures.

EXAMPLE 5

The following three kinds of coupler solutions were prepared.

Dispersion d

15 g of the above-described yellow-forming coupler Y-4 was melted by heating in boiling water. After adding 0.8 ml of a 30% ethanol solution of the above-described nonionic surface active agent N-7 to an aqueous solution containing 0.6 g of the above-described anionic surface active agent A-9 and 30 g of gelatin at 75.degree.C, the coupler melted above was added to the mixture. The resultant mixture was treated six times using a small-scale colloid mill preheated to a temperature above 80.degree.C by passing it through hot water.

(Dispersion e)

A solution prepared by heating a mixture of 15 g of the above-described magenta-forming coupler M-1, 1.0 g of the above-described nonionic surface active agent N-3, 1.2 g of the above-described anionic surface active agent A-13, 10 ml of tri-o-cresyl phthalate, and 50 ml of butyl acetate was added to 200 ml of an aqueous 10% gelatin solution and the mixture was treated for 20 minutes using an electromagnetic striction-type ultrasonic wave generator of 20 K Hz.

(Dispersion f)

A solution prepared by heating a mixture of 100 g of the above-described cyan-forming coupler C-6, 5 g of the above-described nonionic surface active agent N-9, 150 ml of di-n-butyladipate, and 250 ml of butyl acetate was added with stirring to 1.5 liters of an aqueous solution containing 7 g of the water-soluble cyan-forming coupler A-18 and 100 g of gelatin and the mixture was treated 20 times using an emulsifying device having a Pohlman whistle.

It was confirmed that in each of the three kinds of the coupler dispersions, the coupler had been dispersed as fine oil drops having particle sizes of less than 0.4 microns.

The entire amount of the dispersion (d) prepared above was added to 1 kg of a blue-sensitive emulsion containing 50 g of gelatin and 0.25 mole of silver chlorobromide; the entire amount of the dispersion (e) was added to 800 g of a green-sensitive emulsion containing 60 g of gelatin and 0.22 mole of silver chlorobromide; and 500 g of the dispersion (f) was added to 1 kg of a red-sensitive emulsion containing 70 g of gelatin and 0.27 mole of silver chlorobromide.

The blue-sensitive emulsion prepared above was coated on a photographic baryta-coated paper in a dry thickness of 5 microns, an aqueous solution was coated on the blue-sensitive emulsion layer in a thickness of 1 micron as a first intermediate layer, the green-sensitive emulsion prepared above was coated on the intermediate layer in a thickness of 4 microns, an aqueous gelatin solution was coated on the green-sensitive emulsion layer as a second intermediate layer in a thickness of 1 micron, the red-sensitive emulsion prepared above was coated on the second intermediate layer in a thickness of 4 microns, and further an aqueous gelatin solution having dispersed therein the same ultraviolet absorbent as described in Example 1 was coated on the red-sensitive emulsion layer in a thickness of 1 micron as a protective layer to give a color photographic paper. In this case, triethylene phosphamide was used as a hardening agent for gelatin.

During the processes of preparing the photographic emulsions and the color photographic papers, neither a remarkable formation of foam nor the formation of uneven coatings were observed and a uniform light-sensitive materials could be obtained.

When the color photographic paper was exposed through a color negative and processed as described in Example 4, a color print having sharp colors was obtained.

EXAMPLE 6

A solution prepared by heating at 60.degree.C a mixture of 0.5 of the above-described colored coupler L-1, 1.0 g of the cyan-forming coupler C-12, 0.03 g of the nonionic surface active agent N-1, 3 ml of tri-o-cresyl phosphate, and 4 ml of tetrahydrofuran was dispersed by emulsification in 20 ml of an aqueous solution containing 0.1 g of the anionic surface active agent A-11 and 20 g of gelatin using a small-scale homoblender. The entire amount of the dispersion thus prepared was added to 100 g of a red-sensitive emulsion containing 7.0 g of gelatin and 3.3 .times. 10.sup..sup.-2 mole of silver chlorobromide. The resultant emulsion was coated on a triacetyl cellulose film base having an antihalation layer in a dry thickness of 5 microns and dried to give a sample film. When the light-sensitive film thus prepared was exposed to a figure formed by writing on a white paper with a black ink and processed as described in Example 4, a slide for display having sharp lines and characters on a blue background and having high transparency was obtained.

EXAMPLE 7

A solution prepared by heating to about 50.degree.C, a mixture of 10 g of an antioxidant, 2,5-di-tert-butyl hydroquinone, 0.5 g of the above-described nonionic surface active agent N-1, 15 ml of dibutyl phthalate and 15 ml of ethyl acetate was poured in 100 ml of an aqueous 10 % gelatin solution containing 0.4 g of sodium dodecylsulfate (A-1) with stirring and dispersed by stirring for about 5 minutes in a high speed rotary mixer at 10,000 r.p.m. The mean particle size of the antioxidant in the dispersion was about 0.45 .mu. and the antioxidant was uniformly dispersed therein as fine oil drops. When the dispersion was allowed to stand in a cooling box for 2 weeks at 7.degree.C, the mean particle size was observed to be 0.48 .mu..

On the other hand, the mean particle size of the antioxidant in a dispersion prepared in a similar manner as described above except that the nonionic surface active agent N-1 was not contained, was found to be 0.47 .mu.. However, when the dispersion was allowed to stand in a cooling box for 2 weeks at 7.degree.C, the particle size of the antioxidant became 0.65.infin.. The fine crystals of the antioxidant were observed using an electron microscope. When a combination of the nonionic and anionic surface active agent in this invention was employed, no crystals of the antioxidant were formed and the particle size of the antioxidant was almost unchanged.

EXAMPLE 8

A nitro dye (0.2 g) having the following formula: ##SPC5##

0.1 g of the above-described nonionic surface active agent N-1, 0.1 g of the above-described anionic surface active agent (A-11) and 2.0 ml of tri-o-cresyl phosphate were melted by heating. The solution thus obtained was poured in 10 ml of an aqueous 10 wt. % gelatin solution with stirring and dispersed by stirring for about 5 minutes in a high speed rotary mixer at 10,000 r.p.m. the mean particle size of the nitro dye in the dispersion was about 0.3 .mu. and the nitro dye was dispersed therein as uniform fine oil drops. When the dispersion was allowed to stand in a cooling box for 20 days at 7.degree.C, no growth of the particle size was observed and the dispersion showed the maintenance of stable dispersed condition.

A dispersion was prepared in the same manner as described above except using an azo dye of the following formula in place of the above nitro dye: ##SPC6##

The dispersion showed the maintenance of stable dispersed condition. The dispersion thus obtained can be incorporated in a light-sensitive silver halide emulsion to give a photographic emulsion for a silver dye bleaching process disclosed, for example, in U.S. Pat. No. 3,615,494.

While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.

Claims

What is claimed is:

1. A multilayer photographic light-sensitive silver halide element containing a dispersion comprising an aqueous gelatin solution having dispersed therein at least one oleophilic material selected from the group consisting of an oleophilic dye for a silver dye bleaching process, an oleophilic coupler free of a water solubilizing group, an oleophilic ultraviolet absorbent, an oleophilic antioxidant, an oleophilic dye image stabilizing agent and an oleophilic fluorescent brightening agent, in the presence of (a) a nonionic surface active agent containing polyoxypropylene units having a molecular weight of greater than 500 and polyoxyethylene units and a molar ratio of said polyoxyethylene units to said polyoxypropylene units ranging from 0.5 to 0.6, and (b) an anionic surface active agent having an --OSO.sub.3 M group or an --SO.sub.3 M group, wherein M represents a monovalent cation, and a hydrophobic group, said nonionic surface active agent being a slightly water-soluble polyoxyethylene/polyoxypropylene block polymer wherein the entire polyoxypropylene portion thereof has a molecular weight greater than 500 and wherein the molar ratio of all of the polyoxyethylene units thereof to all of the polyoxypropylene units thereof ranges from 0.1 to 0.6.

2. The element of claim 1, wherein said gelatin is acid-treated gelatin, lime-treated gelatin or enzyme-treated gelatin.

3. The element of claim 2, wherein an average molecular weight of said gelatin is greater than 30,000.

4. The element of claim 1, wherein said oleophilic material is an oleophilic dye for a silver dye bleaching process.

5. The element of claim 1, wherein said oleophilic material is an oleophilic leuco dye or color former for pressure sensitive copying sheet.

6. The element of claim 1, wherein said coupler is a coupler which couples with the oxidation product of an N,N-disubstituted p-phenylenediamine developing agent and which has a ballasting group of from 9 to 28 carbon atoms.

7. The element of claim 1, wherein said absorbent is an .alpha.-cyanocinnamic acid ester, a 2-phenylbenzotriazole, or mixtures thereof.

8. The element of claim 1, wherein said nonionic surface active agent is Compound N-1, N-2, N-4, or N-12 represented by the following formulae: ##SPC7##

9. The element of claim 1, wherein said anionic surface active agent is: ##SPC8##

10. the element of claim 1, wherein a combination of said nonionic surface active agent selected from the group consisting of Compounds N-1, N-2, N-4 and N-12 represented by the following formulae: ##SPC9##

and said anionic surface active agent selected from the group consisting of Compounds A-1, A-2, A-11 and A-12 represented by the following formulae: ##SPC10##

is incorporated.

11. The element of claim 1, wherein said aqueous medium is an aqueous solution of gelatin or a derivative thereof, albumin, collodion, gum arabic, agar-agar, alginic acid, an alkyl ester of carboxylated cellulose, hydroxyethyl cellulose, carboxymethyl hydroxyethyl cellulose, polyvinyl alcohol or polyvinyl pyrrolidone, or mixtures thereof.

12. The element of claim 1, wherein said dispersion is present in a light-sensitive silver halide emulsion layer.

13. The element of claim 1 wherein said non-ionic surface active agent has a molecular weight up to 8,000.

14. The element of claim 13, wherein said non-ionic surface active agent has a molecular weight of from 1,000 to 5,000.

15. The element of claim 1, wherein said block polymer has free hydroxy groups at the terminals thereof.