EP0032699A1 - Colour photographic recording material containing an emulsified hydrophilic colour forming compound - Google Patents

Abstract

Hydrophilic coloring compounds such as couplers and coloring compounds for the color diffusion transfer process can be incorporated into photographic materials in emulsified form using oil formers if they are mixed with aliphatic tertiary hydroxyamines in which at least two of the aliphatic groups present carry a hydroxyl group, preferably hydroxyamines of the formula I. : <IMAGE> wherein R¹, R² are the same or different, optionally interrupted by oxygen atoms, alkylene groups having 1 to 4 carbon atoms and R³ is an optionally interrupted by oxygen atoms, alkyl or alkenyl group having 1 to 18 carbon atoms, which is optionally substituted by a hydroxyl group.

Description

The invention relates to a color photographic recording material which, in association with at least one light-sensitive silver halide emulsion layer, contains an emulsified hydrophilic coloring compound.

Hydrophilic color couplers and other coloring compounds are generally added to the photographic coating solutions in the form of an aqueous or aqueous-alcoholic solution. The required amounts of alkali are used in the preparation of the solutions, provided the coupler is not already present in water-soluble form as the alkali salt. Hydrophilic color couplers are often characterized by particularly high coupling speeds and are therefore very desirable in the production of highly sensitive color photographic recording materials. However, the incorporation of hydrophilic compounds from aqueous-alkaline solution in photographic layers has serious disadvantages, inasmuch as that due to the neutralization of the alkaline solutions high salt content in the emulsion causes poor flatness and high brittleness of the materials. Furthermore, the casting solutions generally have to be diluted heavily with water in order to compensate for the increase in viscosity caused by the reaction of the sulfo groups or carboxyl groups with the amino groups of the gelatin. This results in a relatively high wet application of the layers during casting, which in turn requires a great deal of effort in drying the layers. In addition, this method makes it difficult to produce layers with a desired high packing density on color couplers or other coloring compounds.

There has been no lack of attempts to apply the emulsification method known from the incorporation of hydrophobic couplers to hydrophilic compounds, but this has not hitherto been satisfactory because of the low solubility, for example, of the hydrophilic couplers in organic solvents and auxiliary solvents. According to the method described in DE-OS 2 647 487, hydrophilic couplers are dissolved together with bisepoxides in oil formers and dispersed in the silver halide emulsion in the presence of wetting agents. Although hydrophilic couplers can be incorporated by emulsification, the undesirable increase in viscosity of the casting solution cannot be prevented, since the bisepoxides used are gelatin hardening agents and react with the amino groups of the gelatin, which also causes an increase in viscosity.

The invention has for its object to provide a color photographic recording material which contains hydrophilic coloring compounds, without having the disadvantages shown above.

The object is achieved by a color photographic recording material having at least one light-sensitive silver halide emulsion layer and an associated non-diffusing hydrophilic coloring compound, which is characterized in that the light-sensitive silver halide emulsion layer or a non-light-sensitive binder layer adjacent to it is a dispersion of a solution of a hydrophilic coloring compound and one contains aliphatic tertiary hydroxyamines, in which at least two of the aliphatic groups present carry a hydroxyl group, in an oil former.

worin bedeuten

• R¹,_R ² gleiche oder verschiedene, gegebenenfalls durch Sauerstoffatome unterbrochene Alkylengruppen mit vorzugsweise 1 bis 4 Kohlenstoffatomen,
• _R ³ eine gegebenenfalls durch Sauerstoffatome unterbrochene Alkyl- oder Alkenylgruppe mit 1 bis 18, vorzugsweise 1 bis 4, Kohlenstoffatomen, die gegebenenfalls mit einer Hydroxylgruppe substituiert sein kann.

Aliphatic tertiary hydroxyamines used with preference correspond to the following formula (I)

in what mean

• R ¹ , _R ^{2 are the} same or different alkylene groups, preferably interrupted by oxygen atoms, preferably having 1 to 4 carbon atoms,
• _R ^{3 is} an alkyl or alkenyl group with 1 to 18, preferably 1 to 4, carbon atoms which may be interrupted by oxygen atoms and which may optionally be substituted by a hydroxyl group.

The alkylene groups mentioned (R ¹ , R ² ) and the alkyl or alkenyl groups (R ³ ) can be straight-chain or branched and contain, for example, methyl side groups. The alkylene radicals represented by R ¹ and R ² are preferably those which can be derived from the addition of ethylene oxide or propylene oxide to ammonia or primary amines R ¹ -NH ₂ .

• HA-1 Butyl-bis-(2-hydroxyethyl)-amin
  
• HA-2 Bis-(2-hydroxyethyl)-oleylamin
  
• HA-3 Tris-(2-hydroxyethyl)-amin
  
• HA-4 Tris-[2-(2-hydroxyethoxy)-ethyl]-amin
  
• HA-5 Bis-(2-hydroxypropyl)-methylamin
  
• HA-6 Tris-(2-hydroxypropyl)-amin
  
• HA-7 2-Hydroxyethyl-bis-(2-hydroxypropyl)-amin
  

Particularly suitable examples of aliphatic tertiary hydroxyamines (HA) are listed below:

• HA-1 butyl bis (2-hydroxyethyl) amine
  
• HA-2 bis (2-hydroxyethyl) oleylamine
  
• HA-3 tris (2-hydroxyethyl) amine
  
• HA-4 tris [2- (2-hydroxyethoxy) ethyl] amine
  
• HA-5 bis (2-hydroxypropyl) methylamine
  
• HA-6 tris (2-hydroxypropyl) amine
  
• HA-7 2-hydroxyethyl bis (2-hydroxypropyl) amine
  

The aliphatic tertiary hydroxyamines used according to the invention are known compounds which are cited, for example, in Beilstein (Syst. No. 353 and 354).

The color photographic recording material according to the invention generally contains at least three differently spectrally sensitized silver halide emulsion layer units, each of which in turn can consist of one silver halide emulsion layer or several silver halide emulsion partial layers. Associated with the individual silver halide emulsion layers, the color photographic recording material according to the invention contains coloring compounds, that is, compounds which provide image dyes in the course of photographic development. This includes both conventional color couplers and those compounds which, in the course of development, provide diffusing image dyes or their precursors which, after diffusion transfer, produce a color image in an image-receiving layer. In practice, the coloring compounds are selected such that the image dyes produced during processing have a color which is approximately complementary to the color of the light to which the associated silver halide emulsion layers are sensitive. The color-imparting compounds assigned to the red-sensitive layers accordingly provide blue-green image dyes, the color-imparting compounds assigned to the green-sensitive layers provide purple-colored image dyes and the color-imparting compounds assigned to the blue-sensitive layers provide yellow image dyes.

“Mapping” and “mapped” means that the mutual arrangement of the silver halide emulsion layer and coloring compound is of such a kind that an interaction between them is possible which permits an image-wise match between the silver image formed or the image-wise distribution of the undeveloped silver halide on the one hand and the image-wise distribution of the image dye formed on the other hand. This is generally achieved by incorporating the coloring compound either in a light-sensitive silver halide emulsion layer itself or in a non-light-sensitive binder layer adjacent to it. Separating layers can be arranged between silver halide emulsion layer units of different spectral sensitivity, each of which comprises at least one silver halide emulsion layer and at least one coloring compound associated therewith, which may contain substances which react with secondary development products and delay them to render them harmless.

To maintain the above-mentioned assignments, it is furthermore expedient if the color-providing compounds are introduced into the respective layers in a non-diffusing form. This can be done by the usual incorporation methods, whereby hydrophilic coloring compounds are mainly added in the form of aqueous alkaline solutions and hydrophobic coloring compounds mainly in emulsified form using oil paintings. According to the invention, the color photographic recording material now contains, in association with at least one silver halide emulsion layer, a non-diffusing, hydrophilic coloring compound in emulsified form.

According to the invention, "coloring" is considered to be those coloring compounds which, because of their content of alkali-solubilizing groups, are too insoluble in the organic auxiliary solvents used in the incorporation, such as ethanol, ethyl acetate, diethyl carbonate, and above all in the oil formers under consideration have to allow the formation of stable Emulgate. These couplers generally have an excessively high tendency to crystallize in the finished emulsified or in the emulsified form in the cast layer, if it is possible at all to get them in organic solution, which results in a clouding of the layer and a marked deterioration in the photographic properties. especially the maximum color density that can be achieved. With the aid of the tertiary aliphatic hydroxyamines used according to the invention, which presumably react with the alkali-solubilizing groups to form tertiary organic ammonium salts, it is possible to significantly reduce the hydrophilicity of the coloring compounds and thus decisively improve the solubility in the organic auxiliary solvents and the oil-forming agent. Particularly suitable hydrophilic coloring compounds are those which are in their molecules contain a sulfo group and / or one or more other alkali-solubilizing groups such as carboxyl groups (-COOH) or sulfonamide groups (-NH-S02-).

Such coloring compounds have so far been difficult, if at all, to incorporate in emulsified form. The incorporation method according to the invention is equally suitable for incorporating non-diffusing color couplers, from which non-diffusing image dyes are produced by the chromogenic development process, as well as for non-diffusing color compounds for the color diffusion transfer process, from which diffusing dyes are released during photographic processing.

The color couplers used according to the invention can be either conventional 4-equivalent couplers or 2-equivalent couplers, in which a smaller amount of silver halide is required to produce the color. As is well known, 2-equivalent couplers are derived from the 4-equivalent couplers in that they contain a substituent in the coupling point, which is split off during the coupling. The 2-equivalent couplers which can be used according to the present invention include both those which are practically colorless and those which have an intense inherent color which disappears when the color is coupled or is replaced by the color of the image dye produced. The latter couplers can also according to the invention in addition in the photosensitive silver halide emulsion layers are present and serve there as a mask coupler to compensate for the undesirable secondary densities of the image dyes. Known white couplers are also to be counted among the 2-equivalent couplers, but they do not give any dye when reacted with color developer oxidation products. The 2-equivalent couplers include the known DIR couplers, which are couplers which contain a detachable residue in the coupling point, which is released as a diffusing development inhibitor when reacted with color developer oxidation products.

The non-diffusing, diffusing dyes liberating coloring compounds, which can also be incorporated by the method according to the invention, are compounds in which a potentially diffusible dye or dye precursor residue is bound to a carrier residue afflicted with a diffusion-proofing group, such compounds being present by the presence a sulfo group or one or two other alkali-solubilizing groups are so hydrophilic that they cannot be emulsified by the customary methods. The carrier residues mentioned are of such a type that they release a diffusing dye residue either predominantly in oxidized form or predominantly in non-oxidized form, or as a result of a coupling with developer oxidation products. With regard to such coloring compounds, reference must be made to US 3 227 550, US 3 245 789, US 3 443 940, US 3 628 952, US 3 928 312, US 3 980 479, US 3 139 379, DE-OS 2 505 248, DE-OS 2 645 656.

The following may be mentioned as examples of hydrophilic coloring compounds (CP), which according to the invention can be present in emulsified form in the layers of the color photographic recording material:

Suitable oil formers are the customary, more or less hydrophobic, high-boiling compounds, also known as coupler solvents, as described, for example, in US Pat. No. 2,322,027. Special mention should be made here, for example, of dibutyl phthalate (OF-1) and tricresyl phosphate (OF-2). Oil formers containing carboxyl groups can also advantageously be used, for example the succinic acid derivatives of US Pat. No. 3,689,271, US Pat. No. 3,764,336 and US Pat. No. 3,765,897 containing at least one carboxyl group. Examples of such oil formers are given below as oil formers OF-3 to OF-10. Although the oil formers can also have a clearly hydrophilic character in the presence of carboxyl groups, as the example of the last-mentioned compounds shows, it is a common feature of all oil formers that when they are incorporated into a hydrophilic colloid binder they form a second separate phase in the form of small droplets which is retained in the alkaline medium even under the conditions of photographic development. To incorporate the hydrophilic coloring compounds, the oil formers are used in an amount of 0.1 to 2 parts by weight, preferably about 1 part by weight, per part by weight of hydrophilic coloring compounds. Particular advantages are obtained according to the invention in particular if the oil former used has a free carboxyl group and a part of the molecule which shows a certain structural similarity to the tertiary aliphatic hydroxyamines used according to the invention. Such oil formers used with particular preference according to the invention can are obtained by reacting α-alkyl succinic anhydride with tertiary aliphatic hydroxyamines of the formula (I). Oil formers of this type are also described in US 3,689,271. Examples of such oil formers are contained in the following formula collection as oil formers OF-3 to OF-8.

• OF-1 Dibutylphthalat
  
• OF-2 Trikresylphosphat
  
  
  
  
  
  
  
  
  i-_C12H23 bedeutet einen _Tetrapropenyl- oder Triisobutenylrest, wobei diese beiden Reste auch im Gemisch miteinander vorliegen können. Jedoch sind an seiner Stelle auch andere langkettige Kohlenwasserstoffreste verwendbar, z.B. i-C₁₅H₂₉ oder i-C18H35-Reste.

oil generator:

• OF-1 dibutyl phthalate
  
• OF-2 tricresyl phosphate
  
  
  
  
  
  
  
  
  i- _C12H23 means a _T etrapropenyl- or Triisobutenylrest, where these two radicals may be present together in a mixture. However, other long-chain hydrocarbon residues can also be used in its place, for example iC ₁₅ H ₂₉ or i-C18H35 residues.

To produce the color photographic recording material according to the invention, which contains hydrophilic coloring compounds in emulsified form, the coloring compounds together with at least one compound of the formula (I) and the oil former under consideration are expediently first in an organic auxiliary solvent such as ethanol, ethyl acetate, diethyl carbonate, acetone or mixtures thereof. A mixture of 80 parts of ethyl acetate and 20 parts of ethanol or a mixture of, for example, has proven to be advantageous 80 parts of diethyl carbonate and 20 parts of ethanol. The amount of tertiary aliphatic hydroxyamine required generally depends on the number of alkali-solubilizing groups in the hydrophilic coloring compound and can be easily determined by simple experiments. Optimal results are obtained, for example, if the tertiary aliphatic hydroxyamine is used in 0.5 to 2 times the molar amount of the hydrophilic coloring compound used. The oil former is used in an amount of 0.1 to 2 parts by weight per part by weight of hydrophilic coloring compound. The organic solution obtained is emulsified according to customary methods in a hydrophilic colloid, for example in a silver halide emulsion or in a gelatin solution which can be added to a silver halide emulsion at a later point in time or is itself poured into a non-light-sensitive layer after admixing further substances.

The use of the tertiary aliphatic hydroxyamines enables the incorporation of hydrophilic coloring compounds in emulsified form. The invention thus also makes it possible to use hydrophilic and hydrophobic coloring compounds, for example hydrophilic and hydrophobic color couplers, next to one another in the form of a common emulsifier.

example 1

a) 20 g of the red mask coupler CP-12 are taken up in a mixture of 80 ml of ethyl acetate and 4 g of triisopropanolamine (HA-6). 20 g of tricresyl phosphate (OF-2) and 1.3 g of a 75% paste of sodium dodecylbenzenesulfonate were also added. After heating to 50 ° C, the solution obtained was emulsified in 800 ml of a 5% aqueous gelatin solution, which had also been heated to 50 ° C. After removal of the ethyl acetate in a thin-film evaporator, the result was a dispersion which was well liquid at 40 ° C. and which could be distributed completely homogeneously in a silver halide emulsion.

b) For comparison, the same coupler CP-12 was added to an emulsion in the form of an aqueous solution. This was only possible with a solution with a coupler concentration of less than 1% by weight at a pH of 7 (as the sodium salt).

Example 2

a) 3 g of the blue-green dye-providing coloring compound CP-13 were in a mixture of 15 ml of ethyl acetate, 1.7 g of triisopropanolamine (HA-6), 3 g of diethyl lauramide and 0.2 g of a 75% paste of Na dodecylbenzenesulfonate added. The resulting solution was heated to 60 ° C and emulsified in 60 ml of a 40% 5% gelatin solution. After removal of the remaining ethyl acetate in a rotary evaporator, the dispersion obtained had a storage stability of several weeks at 6 ° C.

b) For comparison, 3 g of the coloring compound CP-13 were dissolved in a mixture of 7.5 ml of tetrahydrofuran and 7.5 ml of ethyl acetate with heating. After adding 3 g of diethyl lauramide and 0.2 g of sodium dodecyl sulfonate (75%), the solution, heated to 60 ° C., was emulsified in 60 ml of a 5% gelatin solution. After the dispersion obtained had stood for several hours, crystals separated out.

c) The same procedure was carried out as under b), except that 3 ml of dimethylformamide and 15 ml of ethyl acetate were used as auxiliary solvents. Already after the auxiliary solvent had evaporated off, the dispersion obtained showed clear signs of crystallization and was no longer meltable after a few days.

Example 3

Various emulsions were produced as described in detail in the case of emulsification 3.1.

3.1

50 g of the yellow coupler CP-3 were dissolved in a mixture of 160 g of diethyl carbonate, 40 g of ethanol, 10 g of water, 14 g of triisopropanolamine (HA-6) and 50 g of dibutyl phthalate (OF-1). The solution was stable at room temperature and showed no recrystallization. The solution obtained was emulsified in 1000 ml of a 5% aqueous gelatin solution in the presence of 0.5 g of sodium dodecyl sulfate at 45 ° C. The auxiliary solvent was evaporated.

3.2

With otherwise the same procedure as in 3.1, 50 g of tricresyl phosphate (OF-2) were used as oil formers.

3.3

With otherwise the same procedure as in 3.1, 50 g of the compound OF-6 were used as oil formers.

3.4

With otherwise the same procedure as in 3.1, 50 g of the compound OF-7 were used as oil formers.

3.5

With otherwise the same procedure as in 3.1, 50 g of the compound OF-9 were used as oil formers.

3.6

In otherwise the same procedure as in 3.1, 50 g of the compound OF-10 were used as oil formers.

3.7

With otherwise the same procedure as in 3.1, 11 g of compound HA-3 were used instead of compound HA-6.

3.8

With otherwise the same procedure as in 3.1, 13 g of the compound HA-7 were used instead of the compound HA-6.

To investigate the viscosity behavior during digestion at 40 ° C., 1 kg each of the emulsions obtained were mixed with 780 g of a silver halide emulsion (gelatin content 7.5%). The viscosities found are shown in Table 1 below. A casting solution (test 3.9) was used for comparison, which was obtained by mixing 374 ml of a 10% aqueous alkaline solution of the yellow coupler CP-3 and 636 g of a silver halide emulsion (gelatin content 7.5%). was obtained. The measured viscosities [mPa.s] of the freshly prepared casting solutions and after 3 or 6 hours of digestion at 40 ° C. are shown in Table 1 below.

Except for the comparative experiment 3.9 with the alkaline dissolved coupler all the casting solutions show a normal viscosity curve, ie slightly ^g ehende values due to slight gelatin degradation. The increase in viscosity observed in experiment 3.9 leads to malfunctions during coating, since casting solutions often have a standing time of 6 to 12 hours between manufacture and casting.

The bracketed values in Table 1 are viscosity values which were measured in the same way on the pure emulsions (without admixing the silver halide emulsion). For comparison, in the case of the alkaline dissolved coupler (test 3.9), 200 ml of a 5% aqueous alkaline solution of the coupler CP-3 were mixed with 100 ml of 10% gelatin solution; pH 6.4.

Table 2 shows the maximum color densities of various photographic materials which were obtained with the previously described emulsions 3.1 to 3.8 by mixing with a silver bromide emulsion (ratio of A _G NO ₃ to coupler = 1: 1.5) and casting on a paper base. The development was carried out in a conventional manner using N-butyl-N-ω -sulfobutyl-p-phenylenediamine as the developer substance. For comparison (3.9), a corresponding material was produced with the alkaline coupler CP-3. One sample of each of the materials thus produced was exposed and developed in the fresh state and a second sample after storage (2 days; 60 ° C.; 60% relative atmospheric humidity). The maximum color density Dmax and the density loss Δ Dmax during storage are given in Table 2.

Example 4

Emulsifier of a hydrophilic and a hydrophobic yellow coupler.

In a mixture of 100 g of diethyl carbonate, 40 g of ethanol, 10 g of water and 50 g of tricresyl phosphate (OF-2) the amounts of triisopropanolamine (HA-6), yellow coupler X and yellow coupler CP-3 shown in Table 3 below were taken up.

Yellow coupler X is a hydrophobic yellow coupler of the formula:

The oil phase obtained was emulsified in 1000 ml of a 5% gelatin solution with 0.5 g of sodium dodecylbenzenesulfate, mixed with a silver halide emulsion while setting an AgNO ₃ / coupler ratio of 1: 1.5 and poured onto a paper support; Silver coating 0.54 g AgNO ₃ / m ² . After exposure and customary color processing, the maximum color densities shown in Table 3 were measured.

In this example, optimal color yield is obtained at a coupler ratio of 20:80 (hydrophilic / hydrophobic).

Example 5

Emulsifier of a hydrophilic and a hydrophobic magenta coupler.

5.1 (comparison)

50 g of the hydrophobic coupler Y were dissolved in 160 ml of diethyl carbonate and 50 g of tricresyl phosphate (OF-2). The solution obtained was emulsified in 500 ml of a 10% gelatin solution with the addition of 25 g of a 10% solution of sodium alkylnaphthalene sulfonate.

The hydrophobic coupler Y has the formula

Nach dem Abdampfen des Lösungsmittels wurde das Emulgat mit einer Silberbromidemulsion im Verhältnis AgN0₃/ Kuppler = 1:0,7 vermischt und auf einer Papierunterlage vergossen. Silberauftrag: 0,46 g AgN0_3/m².

After the solvent had been evaporated off, the emulsate was mixed with a silver bromide emulsion in the ratio AgNO ₃ / coupler = 1: 0.7 and poured onto a paper base. Silver application: 0.46 g AgN0 _{3 /} m ² .

5.2

35 g of the hydrophobic coupler Y, 15 g of the hydrophilic coupler CP-5 and 6 g of the compound HA-6 according to the invention were dissolved in the manner given under 5.1, emulsified in gelatin and cast on a paper base.

5.3.

As described in 5.2, a photographic material was produced, using 50 g of the oil former OF-7 instead of tricresyl phosphate.

After exposure and customary color processing (color developer: N-butyl-N-ω-sulfobutyl-p-phenylenediamine), the maximum color densities shown in Table 4 were measured.

Claims (7)

1) Color photographic recording material with at least one light-sensitive silver halide emulsion layer and an associated non-diffusing hydrophilic coloring compound, characterized in that the light-sensitive silver halide emulsion layer or an adjacent non-light-sensitive binder layer is a dispersion of a solution of a hydrophilic coloring compound and an aliphatic tertiary hydroxyamine, in which contains at least two of the aliphatic groups present a hydroxyl group in an oil former. 2) Recording material according to claim 1, characterized in that the aliphatic tertiary hydroxyamine corresponds to the following formula:

in what mean _R ¹ , _R ^{2 are} identical or different, optionally interrupted by oxygen atoms, alkylene groups having 1 to 4 carbon atoms and _R ^{3 is} an alkyl or alkenyl group with 1 to 18 carbon atoms which is optionally interrupted by oxygen atoms and which is optionally substituted by a hydroxyl group. 3) Recording material according to claim 1, characterized in that the hydrophilic coloring compound contains a sulfo group and / or one or two carboxyl groups (-COOH) or sulfonamide groups (-NH-S0 ₂ -). 4) Recording material according to claim 1, characterized in that the aliphatic tertiary hydroxyamine is present in 0.5 to 2 times the molar amount, based on the hydrophilic coloring compound. 5) Recording material according to claim 1, characterized in that the hydrophilic coloring compound is a hydrophilic color coupler. 6) recording material according to claim 5, characterized in that the oil-former in addition to the hydrophilic color coupler and the aliphatic tertiary hydroxy amine, a hydrophobic Farbkup dissolved ^p ler. 7) Recording material according to claim 1, characterized in that the oil former is a reaction product of an aliphatic tertiary hydroxyamine, in which at least two of the aliphatic groups present carry a hydroxyl group, with a succinic anhydride which, in the α-position, contains an aliphatic radical which makes it resistant to diffusion.