US3689271A

US3689271A - Incorporation process for materials used to form photographic layers

Info

Publication number: US3689271A
Application number: US814808A
Authority: US
Inventors: Fritz Nitttel; Erich Reckziegel
Original assignee: Agfa Gevaert AG
Current assignee: Agfa Gevaert AG
Priority date: 1968-04-11
Filing date: 1969-04-09
Publication date: 1972-09-05
Anticipated expiration: 1989-09-05
Also published as: DE1772192C2; GB1222753A; BE731288A; DE1772192A1; FR2006109A1

Abstract

THE EMULSIFICATION OF ADDITIVES INTO A PHOTOGRAPHIC EMULSION IS STABILIZED BY COMBINING THE ADDITIVE WITH CERTAIN SECONDARY CARBOXYLIC ACIDS BEFORE THEY ARE EMULSIFIED.

Description

United States Patent US. CI. 96-84 11 Claims ABSTRACT OF THE DISCLOSURE The emulsification of additives into a photographic emulsion is stabilized by combining the additive with certain secondary carboxylic acids before they are emulsified.

The present invention relates to a process for incorporating substances in materials which are used to form photographic layers and auxiliary layers.

It is already known that emulsifiable compounds such as colour couplers, UV absorbers, white toners and similar additives may be incorporated in gelatine solutions by using so-called oil forming agents. According to US. Pats. Nos. 2,322,027 and 2,533,514, for example, colour couplers are incorporated in water-soluble colloidal materials commonly used in the production of photographic products by dissolving the colour coupler in an organic liquid of relatively high boiling point which is insoluble in water, and emulsifying or dispersing the solution in the colloidal material. This process has the disadvantage that hydrophilic developers, e.g. N-butyl-N-w-sulphobutylp-phenylenediamine, penetrate the oil droplets only to a slight extent, if at all. This causes loss in sensitivity, flattening of the gradation and a reduced image density. Also, residues of hydrophobic developer may be retained in the droplets and cause fogging when the photographic material is treated in oxidising bleaching baths.

Hydrophilic substances such as colour couplers which carry a carboxyl group are incorporated in gelatine in the form of their sodium salts. Since the gelatine solutions are subsequently adjusted to a pH of 6.2 to 6.5, these compounds are generally present in microcrystalline distribution. The protective colloidal action of gelatine is in many cases insufiicient, so that recrystallisation occurs influencing sensitivity, gradation and colour brilliance in an uncontrollable manner.

Although hydrophilic substances such as colour couplers which carry SO H groups are generally more compatible with gelatine than the above mentioned compounds, recrystallisation still occurs in many cases during digestion of the gelatin, especially in the case of compounds that have an enolate form which promotes solubility in an alkaline medium. At the pH values of 6.2-6.5 to which most emulsions are adjusted, the action of the SO Na group in preventing recrystallisation is no longer sufiicient. This again leads to a loss in sensitivity, reduction in the colour brilliance and loss in gradation. The use of lithium salts and increased amounts of wetting agents has been found to also bring no significant improvements.

Numerous hydrophilic substances of the above mentioned types, moreover, have the property of increasing the viscosity of the casting solution, in some cases to such an extent that such solutions can no longer be worked up.

It is an object of the present invention to provide an incorporation process which does not have the above mentioned disadvantages.

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We have now found a process for the production of photographic layers which contain additional substances emulsified therein in the form of a solution and the resulting emulsified mixture being applied to a support, which process is characterised in that the additional substances are emulsified together with compounds of the following general formula:

in which R represents an alkyl or alkylene group which has 1 to 18 carbon atoms, preferably 5 to 12 carbon atoms and is branched and may be substituted, preferably by OH and/or OR groups R represents a hydrogen atom, an alkyl or alkylene group which has 1 to 18 carbon atoms, preferably 5 to 12 carbon atoms and is branched and may be substituted, preferably by OH and/or OR groups, and Q represents an alkyl group which has 1 to 9 carbon atoms and may be substituted, preferably by COOH, or one of the groups COX or -CH COX in which X may have the following meaning: (1) a hydrogen atom, a hydroxy group, an alkoxy group with 1 to 18 carbon atoms and preferably 5 to 12 carbon atoms, (2) an O-alkylene-[O-alkylene] -O-alkyl group in which the alkylene and alkyl radical preferably contain 1 to 4 carbon atoms and n denotes 0 to 10,

(3) an amino group, especially a substituted amino group such as 1H-alkyl,

alkyl aryl aryl N NH-ary1,-N N

alkyl aryl alkyl NH-cycloalkyl, or

in which the alkyl radical may contain up to 21 carbon atoms, is preferably branched and may in turn be substituted as may also the aryl radical, especially with such groups as OH, COOH, OCH CN and phenyl,

(4) a hydrazine group which may be substituted by an alkyl group preferably having 1 to 5 carbon atoms or by the group which alkyl substituents may in particular be substituted by OH, COOH, OCH and CEN groups,

(5 a hydroxylamino group. (6) or a group -0-oH oH3)oH21 IY in which Y represents the group wherein R has the above indicated meaning and Z stands for CH or is equal to Y.

The following compounds are particularly suitable for use in the process of the invention;

The radical i-C H appearing in many compounds in the above list represents the group l,1,3,5-tetramethylocten-(2)-yl whose structural formula is Versatic acid 911 is an isomeric mixture of highly branched tertiary and secondary carboxylic acids having 9 to 11 carbon atoms, and Versatic acid 1519 is a mixture of carboxylic acids of the same type having 15 to 19 carbon atoms.

The method of preparation of the compounds used in the present invention is generally known. In order to prepare the type of compound which contains a free carboxyl group in addition to the radical COX defined above, monoalkylated cyclic carboxylic acid anhydrides are reacted with alcohols or with amines.

The process of the present invention is generally carried out as follows:

Emulsifiable substances such as colour couplers, UV absorbents, white toners or stabilisers are dissolved together with the compounds according to the present invention, in an organic solvent which is immiscible with water and emulsified with the casting solution for the photographic layer, using an emulsifying apparatus. The emulsifying apparatuses used for this purpose may, for example, be high speed stirrers, so-called mixing sirens, ultraturrax or ultrasound apparatuses.

Hydrophilic substances, e.g. the above mentioned colour couplers which contain carboxyl groups or hydrophilic substances such as colour couplers which contain SO H groups are incorporated by a different method. In this case, the compounds of the present invention are dissolved in an alkaline medium together with the additives which are present in an alkali soluble form and a wetting agent, and this solution is added with intensitive stirring to an acidified casting solution as explained above. The pH of the casting solution is thereby shifted to 6.2-6.5. Certain colour couplers which do not contain SO H or COOH groups and which are soluble in alkali as enolates can be incorporated in the same manner.

The compounds of the present invention have the advantage that, apart from a very pronounced tendency to prevent crystallisation, especially in the presence of colour couplers which have been incorporated by emulsification, they do not prevent the coupling of oxidised colour developers. The compounds form soaps at alkaline pH values, i.e. during development. In contrast to lower carboxylic acids or those which have only a short fatty acid radical, the additives used with the compounds according to the present invention do not separate out in an alkaline medium. They therefore also prevent precipitation of the dye produced or the appearance or turbulent colour surfaces. The separation of colour components by crystallisation which might otherwise occur even during digestion is also prevented. Furthermore, in contrast to the known hydrophobic oil-forming agents, the compounds used according to the present invention cause neither flattening of the gradation nor reduction in the image density and in addition they substantially prevent the increase in viscosity which many colour couplers containing COOH or SO H groups cause during digestion.

The compounds of the present invention are generally employed in the proportion of 0.1 to 10 parts by weight per part by weight of the substance which is to be incorporated, the preferred range lying between 0.3 and 1 part by weight. The use of higher concentrations of up to 10 parts by weight is of interest in cases in which only small quantities of an additive, e.g. a sta-biliser, are to be incorporated into the casting solution.

Examples of suitable organic solvents which are immiscible with Water are the chlorinated short-chained aliphatic compounds such as methylene dichloride, as well phatic compounds such as methylene di chloride, as well as ethyl acetate.

The binder used for the photographic layers is preferably gelatine but this may be partly replaced by other film-forming natural or synthetic polymers. Suitable polymers for this purpose include alginic acid and its derivatives such as its salts, esters, or amides, carboxymethyl cellulose, alkyl cellulose, starch and its derivatives, polyvinyl alcohol, copolymers of vinyl alcohol and vinyl acetate, polyvinyl pyrrolidone, anionic polyurethanes and other latices such as copolymers of acrylic ester, acrylonitrile and acrylamide.

The photographic layers may contain any known additives such as anti-fog agents, stabilisers, hardeners, plasticisers and wetting agents. In addition, they may be both chemically and spectrally sensitised.

The light sensitive emulsions may be chemically sensitised by carrying out the ripening in the presence of small quantities of sulphur-containing compounds such as allyl isothiocyanate, allyl thiourea and sodium thiosulphate. The light sensitive emulsions may also be sensitised with reducing agents, e.g. the tin compounds described in Belgian Pats. Nos. 493,464 and 568,687, and the iminoaminomethanesulphinic acid compounds described in Belgian Pat. No. 547,323 or small quantities of noble metal compounds such as compounds of gold, platinum, palladium, iridium, ruthenium and rhodium. The emulsions may also be sensitised with polyalkylene oxide derivatives, e.g. a polyethylene oxide having a molecular weight of between 1000 and 20,000, condensation products of alkylene oxide and aliphatic alcohols, glycols, cyclic dehydration products of hexitols, alkyl substituted phenols, aliphatic carboxylic acids, aliphatic amines, aliphatic diamines and amides. The condensation products have a molecular weight of at least 700, preferably more than 1000. To achieve special effects, combinations of these sensitisers may, of course, be used as described in Belgian Pat. No. 537,278 and in British patent specification No. 727,982.

EXAMPLE 1 A solution of 40 g. of the following blue green coupler HsC 5 11 and 20 g. of Compound 3 dissolved in 160 cc. of ethyl acetate is emulsified in 1 kg. of a 10% gelatine solution at 50 C. After removal of the solvent in a thin layer evaporator, the emulsion is added to 1 kg. of a red sensitised silver halide gelatine emulsion which contains 0.33 mol of silver bromide, 0.0075 mol of silver iodide and g. of gelatine per kg.

The mixture prepared in this Way is used as a red sensitive layer containing a blue green coupler, in a multilayered colour photographic material in the usual manner.

The flattening of the gradation and the reduction in the colour density which occur with the known hydrophilic developers do not occur in this case.

7 EXAMPLE 2 40 g. of the following blue green coupler or: @iD-b ONHC Hu EXAMPLE 3 25 g. of the following purple coupler are emulsified in 1 kg. of 10% gelatine solution in the same manner as in Example 1 together with 12.5 g. of Compound 26 and added to 1 kg. of a green sensitised halide gelatine emulsion.

The mixture is worked up as in Example 1. The green sensitive layer has the same properties as the emulsion described in Example 1.

EXAMPLE 4 36 g. of the following yellow coupler iuHaa Q-o 001120 ONH- F COOH together with 18 g. of Compound 30 are dissolved in a mixture of 360 ml. of water, 40 ml. of 5 N NaOH, and the resulting solution 75 ml. of methanol and emulsified at 40 C. in 1 litre of a gelatine solution which contains 90 ml. of a 21% solution of monosodium citrate. The emulsion thus formed has a pH of 6.1 and is added to 1 kg. of a blue sensitive silver halide gelatine emulsion which contains 0.33 mol of silver bromide, 0.0075 mol of silver iodide and 90 g. of gelatine per kg.

The final mixture is worked up in the same manner as in Example 1 to give a blue sensitive layer which contains yellow coupler and has the same properties as the emulsion obtained in Example 1. When compound 30 is omitted, the coupler crystallises out after a short time.

EXAMPLE 5 22.5 g. of the following purple coupler together with 12 g. of Compound 28 and 1 g. of the his- (2-ethyl)-hexyl ester of sulphosuccinic acid as wetting agent are dissolved in a mixture of 230 ml. of water, 30 m1. of 5 N NaOH and 75 ml. of methanol and thesolution emulsified at 40 C. in 1 litre of a 10% gelatine solution which contains 40 ml. of a 21% monosodium citrate solution. The resulting emulsion is added to 1 kg. of a green sensitised silver halide gelatine emulsion which contains 0.33 mol of silver bromide, 0.0075 mol of silver iodide and g. of gelatine per kg.

When the mixture has been worked up in the manner described previously, similar results to those indicated in Example 4 are obtained.

EXAMPLE 6 25 g. of the following purple coupler l SOaH together with 12.5 g. of Compound 4 and 1 g. of the bis- (2-ethyl)-hexyl ester of sulphosuccinic acid as wetting agent are dissolved in a mixture of 250 ml. of water, 50 ml. of 1 N lithium hydroxide solution and 75 ml. of methanol and the solution emulsified at 40 C. in 1 litre of a 10% gelatine solution which contains 40 ml. of 21% monosodium citrate solution.

The emulsion is added to 1 kg. of a green sensitised silver halide gelatine emulsion which contains 0.33 mol of silver bromide 0.0075 mol of silver iodide and 90 g. of gelatine per kg. The mixture is worked up as before. When Compound 4 is omitted the coupler crystallises out on digestion.

EXAMPLE 7 40 g. of the following yellow coupler SO NHCH:

together with 20 g. of Compound 3 and 1 g. of the his- (2-ethyl)-hexyl ester of sulphosuccinic acid as wetting agent are dissolved in a mixture of 350 ml. of water, 20 ml. of 5 N NaOH and 75 ml. of methanol and the solution stirred into 1 kg. of blue sensitive halide gelatine emulsion which contains 0.33 mol of silver bromide, 0.0075 mol of silver iodide and g. of gelatine per kg. 40 ml. of 21% monosodium citrate solution are added to the emulsion before the solution of the components is stirred in.

The result is similar to that obtained in Example 6.

EXAMPLE 8 40 g. of the yellow coupler used in Example 7 together with 20 g. of Compound 2 are dissolved as indicated in that example and added to 1 kg. of a blue sensitive silver halide gelatine emulsion which contains 0.33 mol of silver bromide, 0.0075 mol of silver iodide and 120 g. of gelatine per kg. and to which 40 ml. of a 21% monosodium citrate solution have previously been added. The result is similar to that obtained in Example 6.

EXAMPLE 9 40 g. of the yellow coupler used in Example 7 together with 20 g. of Compound 7 are dissolved as described in that example and added to 1 kg. of a blue sensitive silver halide gelatine emulsion which contains 0.33 mol of silver bromide, 0.0075 mol of silver iodide and 120 g. of gelatine per kg.-The result'is similar to that obtained in Example 6.

9 EXAMPLE 10 30 g. of the following UV absorber Ho (min N together with 10 g. of Compound 25 are dissolved in ethyl acetate and emulsified in 1 kg. of a gelatine solution. The emulsion is cast as a UV protective layer over a colour photographic material.

The protective layer produced by the process according to the invention is clear whereas a layer produced without Compound 25 remains cloudy.

EXAMPLE 11 30 g. of the UV absorber used in Example 10 together with g. of Compound 28 are dissolved in ethyl acetate and emulsified in 1 kg. of a 10% gelatine solution. The emulsion is cast as a UV protective layer over a colour photographic material. The result is similar to that obtained in Example 10.

EXAMPLE 12 0.5 g. of the following white toner N- N O Cfis 100 mg. of a stabiliser of the following formula together with 3 g. of Compound 3 are dissolved in 10 ml. of methylene di chloride and the solution emulsified in 1 kg. of a 10% gelatine solution. The emulsion is used as a protective layer for colour photographic material.

The presence of Compound 3 prevents diffusion of the stabiliser into the adjacent layers.

EXAMPLE 14 22 g. of the following purple coupler together with 15 g. of Compound 28 and 1 g. of the bis- (2-ethy1)-hexyl ester of sulphosuccinic acid as wetting agent are dissolved in a mixture of 400 ml. of water, ml. of 5 N NaOH and 60 ml. of methanol and the solution emulsified at 40 C. in 1 litre of 10% gelatine solution which contains 40 ml. of a 21% monosodium citrate solution. The emulsion is added to 1 kg. of a green sensitised silver halide gelatine emulsion which contains 0.33 mol of silver bromide, 0.0075 mol of silver iodide and g. of gelatine per kg. The addition of Compound 28 prevents the steep rise in viscosity caused by the colour coupler when Compound 28 is absent.

We claim:

1. In the process of emulsifying materials into an aqueous dispersion of a hydrophilic photographic binder, the improvement according to which the emulsification is effected with the help of at least one compound having the formula:

where R represents an alkyl or unsaturated alkyl and has at least 5 carbon atoms,

Q is COX or an alkyl having up to 9 carbon atoms and a COX substituent, and

X is hydroxy, alkoxy of up to 18 carbons which may be alkoxy or amino substituted, or amino substituted by alkyl or aryl radicals of up to 21 carbons 'which radicals can be OH, CN, alkoxy, carboxy or amine substituted, or a hydrazine or hydroxylamine radical and an amount effective to stabilize the emulsification.

2. In the process of emulsifying materials into a gelatin emulsion, the improvement according to which the emulsification is effected with the help of at least one compound having the formula:

where R represents a branched alkyl or unsaturated alkyl and has from 5 to 12 carbon atoms,

Q is COX or CH COX, and

X is hydroxy, alkoxy of up to 18 carbons which may be alkoxy or amino substituted, or amino substituted by alkyl or aryl radicals of up to 21 carbons which radicals can be OH, CN, alkoxy, carboxy or amine substituted, or a hydrazine or hydroxylamine radical and in an amount effective to stabilize the emulsification.

3. The combination of claim 2 in which R is l,l,3,5- tetramethyl-octen- (2 -yl.

4. The combination of claim 2 in which the material to be emulsified is first dissolved in a volatile organic solvent along with the stabilizing compound, and the solution thus formed is emulsified into the gelatin emul- 5. The combination of claim 4 in which the solvent is methylene dichloride.

6. The combination of claim 4 in which the solvent is ethyl acetate.

7. The combination of claim 2 in which the material to be emulsified is soluble in aqueous alkali, it is dissolved in an aqueous alkaline solution along with the stabilizing compound and the resulting solution emulsified into the gelatin emulsion.

8. A photographic gelatin emulsion containing emulsified photographic additive particles, said particles also having at least one compound of the formula:

t R-C-COOH where R represents an alkyl or unsaturated alkyl and has at least 5 carbon atoms,

Q is COX or an alkyl having up to 9 carbon atoms and a COX substituent, and

X is hydroxy, alkoxy of up to 18 carbons which may be alkoxy or amino substituted, or amino substituted by alkyl or aryl radicals of up to 21 carbons which radicals can be OH, CN, alkoxy, carboxy or amine substituted, or a hydrazine of hydroxylamine radical and in an amount effective to stabilize the emulsification.

9. The combination of claim 8 in which the photographic additive is a color coupler.

10. The combination of claim 8 in which the photographic additive is a UV absorber.

11. The combination of claim 8 in which the photographic additive is a white toner.

References Cited UNITED STATES PATENTS J. TRAVIS BROWN, Primary Examiner US. Cl. X.R.