DE2044992A1 - Acidic polymeric photographic coupling agents - - based on poly(meth)acrylic acid giving improved definition with les - Google Patents

Abstract

Homo- or co-polymers of (meth)acrylic acid are dissolved in DMF and reacted with dicyclohexylcarbodiimide and after filtration with an NH2 gp.-contg. lower molecular coupling agent to give a polymeric coupling agent contg. pref. 15-85 mol.% of recurring units -C(COOH)(R)-CH2 and 85-15 mol % of where R is H or Me and coupler is the lower molecular coupling agent, which will react with colour developers to give blue-green, purple, yellow or esp, colourless (white) cods.

Description

Process for Making Polymeric Photographic Couplers ia Invention relates to a method of making polymeric photographic couplers, and in particular of carboxyl-containing polymeric photographic amplifiers.

For the definition of coupler substances in the binder layers Various methods have been proposed for photographic materials. Man can work, for example, in a heterogeneous phase and the solution is hydrophobic black couplers in a low-boiling organic solvent, optionally with additives a high-boiling organic, so-called coupler solvent, in the hydrophilic Emulsify binder. Or you can work in a homogeneous phase and the couplers, which in this case are made alkali-soluble by sulfo or carboxyl groups and with diffusion-inhibiting, long-chain aliphatic radicals were provided, the silver halide emulsion add. It has also been proposed to use polymeric couplers.

For the production of polymeric couplers and basically two different ones Ways possible. On the one hand, one can start from monomeric coupler units that are capable of polymerisation Groups, see B. Vinyl or acrylamide groups, and these, optionally together polymerize with suitable comonomers.

On the other hand, it is also possible to use a preformed framework polymer start out, which contains suitable functional groups, over which one the corresponding can attach monomeric coupler units. Examples are copolymers from maleic anhydride and styrene or N-vinylpyrrolidone with amino groups monomeric coupler substances to polymeric carboxyl-containing coupling substances implemented. Because there are two latent carboxyl groups in each maleic anhydride unit are present and since each maleic anhydride unit reacts with a carbonamide bond to form a coupler molecule and a free carboxyl group can act on this Way, only a maximum of 50% of all potential carboxyl groups are implemented.

It has now been found that one can produce polymeric couplers can also start from polymers with free carboxyl groups, e.g. from polyacrylic acid or polymethacrylic acid, if the reaction with low molecular weight amino groups coupler compounds in the presence of a dehydrating carbodiimide compound performs. In this way, up to 100 ffi of all carboxyl groups can be found in carbonamide bonds are reacted between the backbone polymer and the coupler groups.

The invention therefore relates to a process for the production of carboxyl-containing polymeric photographic coupler, characterized in that one is a homo- or Copolymer of acrylic acid or methacrylic acid dissolves in dimethylformamide with dicyclohexylcarbodiimide reacted and then with an amino group-containing low molecular weight coupler compound lets react.

To carry out the process, the basic polymer framework is all carboxyl-containing polymers are suitable, provided they are in dimethylformamide are sufficiently soluble, in particular homo- or copolymers of acrylic acid and of methacrylic acid. Useful comonomers all come with acrylic acid or methacrylic acid copolymerizable monomers in question, provided they do not contain functional groups, which would lead to disturbances in the reaction according to the invention. Mention should be made for example vinyl ethers, vinyl esters, N-vinylpyrrolidone, styrene, acrylonitrile, acrylic acid esters and maleic anhydride. The polymers used preferably contain more than 40 mol% acrylic acid or

Methacrylic acid.

In the case of the low molecular weight coupler compounds containing amino groups it is a cyan coupler, magenta coupler or yellow coupler, or preferably to white couplers which each carry at least one amino group and which as such are known. The couplers react with oxidized color developing agents, in particular those of the p-phenylenediamine type with the formation of a blue-green, a purple one or a yellow image dye, or in the case of the white coupler also with formation colorless substances. The cyan couplers are derived, for example, from phenol, respectively.

oC-naphthol, the purple couplers of pyrazolone, or indasolone and the Yellow couplers from ß-ketocarboxylic acid derivatives.

The white couplers are generally pyrazolone derivatives, However, in the coupling site contain a substituent that is involved in the reaction is no longer split off with color developer oxidation products.

Reference is made, for example, to the article by W. PUschel in Messages from the research laboratories of Agfa-Gevaert AG ", Volume IV, page 352. The coupling property must occur in the reaction with the framework polymer remain.

The reaction of the carboxyl group-containing framework polymer with the amino group-containing coupler substances is carried out in dimethylformamide, in which the components to be converted are generally soluble, while the N, N'-dicyclohexylurea formed in the reaction precipitates and is easily separated off can be. The reaction is generally exhermic and probably takes place in two stages.

First, two equivalents of carboxylic acid react with one equivalent Dicyclohexylcarbodiimide with formation of one equivalent of anhydride and one equivalent N, N'-dicyclohexylurea. The latter fails and can be severed without difficulty will. However, it is also possible and in many cases useful to first put it in to leave the mixture and only after the further conversion of the anhydride formed to be separated with the amino compound. The reacts in the second reaction stage Anhydride group with one equivalent of the amino group-containing coupler under Formation of carbonamide bonds and regression of one equivalent of free carboxylic acid. Provided that dicyclohexyl calbodiinide and amino compound are used in sufficient excess it is possible by the method according to the invention, more than half to implement all of the carboxyl groups originally present in the polymer. If desired, 100% conversion can even be achieved, but it has to do with the use of the polymeric couplers produced al favored, if a certain Share of free carboxyl groups is still present.

With the inventive method there is also the possibility of part of the carboxyl groups with the amino groups of the monomeric coupler compounds implement and the remaining carboxyl groups with the assistance of excess Cyclohexylcarbodiimide at least partially to implement further, for example by Reaction with ammonia or non-coupling in amines or with alcohols. All these Reactions proceed very easy, under very gentle conditions and can be carried out in a one-pot process without isolating the respective intermediate products will. The products are almost colorless or only slightly colored and are easily familiar getting cleaned. A dark color, like the one in the conversion of polyacrylic acid observed with thionyl chloride does not occur. The process is very versatile and therefore offers the possibility, by varying the content of coupler units, on free carboxyl groups and on otherwise converted carboxyl groups, as well as finally the comonomers originally present in the framework polymer, the Adapt properties to the respective requirements.

The polymeric couplers produced by the process according to the invention thus essentially consist of structural units of the following formulas 1 and II: where R denotes hydrogen or methyl and "COUPLER" denotes the remainder of a low molecular weight photographic coupler which reacts with color developer oxidation products to form a colorless compound or a blue-green, purple or yellow dye, as well as optionally other constituents which are either produced by copolymerization with acrylic or methacrylic acid were present from the start in the framework polymer or which can be obtained subsequently, for example by converting the free carboxyl groups of the polyacrylic or polymethacrylic acid.

As examples of the polymeric couplers produced by the process of the present invention, the following may be mentioned. In the formulas, unless otherwise stated, x to y is related to 1 to 1.

The method according to the invention should be carried out by the following manufacturing specification explained.

Coupler 1 108 g (1.5 mol) of polyacrylic acid are in 600 ml of dry Dimethylformide dissolved at 7000, cooled to 1500 and with stirring at this temperature 216.3 g (1 mol + 5%) of dicyclohexylcarbodiimide were added. After a short delay the temperature rises to approx. 60 ° C despite cooling. The mixture is stirred for 1 hour without any further After cooling, then cools to 2500 and sucks off the dicyclohexylurea. It is washed six times with 100 ml of dry dimethylformamide each time. The received The filtrate is stirred into a slurry of 203 g of 1- (3'-aminophenyl) -3,4-dimethylpyrazolon-5 poured into 300 ml of dry dimethylformamide.

After about 15 minutes everything is clearly resolved. Within a half Hour, the viscosity rises sharply, so that it can no longer be stirred. To If left to stand overnight, the viscosity drops again and it still separates some dicyclohexylurea from. While stirring and cooling with ice, 1.25 liters of 1NaOH are obtained added and 1 l of water.

After 10 minutes, it is filtered off with suction and washed with dilute NaOH. The viscous alkaline solution is added dropwise to 2 l with stirring and ice cooling 1nHCl. The mixture is stirred for 15 minutes, the precipitate is filtered off with suction and washed copiously with water. Finally, it is stirred with 3 l of methanol, filtered off with suction, then without washing first in the air, later dried over CaC12 in a desiccator.

Yield: approx. 285 g.

The other polymeric couplers are made in a similar manner.

The polymeric couplers made in accordance with the present invention are present of carboxyl groups alkali-soluble and can in aqueous alkaline solution the binder, for example, the gelatine, with which they are very well tolerated, can be added. Since they already have very good layer-forming properties themselves, comes along with very little gelatin.

It is therefore possible to use essentially the same amount of coupler units to accommodate thinner layers than when using low molecular weight couplers. By varying the content of couplers, one can also achieve the Increase or decrease the density of the parchment and thereby the gagsbian layer thickness Adapt to the respective needs while, on the other hand, by varying the G. on free carboxyl groups, the mechanical properties of the layers, such as the suppleness, can change. For example, they have advantageous properties polymeric couplers containing 15 to 85 mol% of groups of the formula 1 and 85 to 15 Contain moles of groups of the formula II.

Particularly noteworthy are those resulting from the method according to the invention produced polymeric white couplers. White couplers are made in multi-layer color photographic materials Essentially used and incorrect diffusion of oxidized color developer molecules to prevent. For this purpose, the white couplers are advantageously used in double layers housed between the individual color-forming layers.

Since the sharpness of the color photographic multilayer materials with decreasing total layer thickness should be improved the single ones Layers, and in particular also the intermediate layers containing white coupler, if possible be kept thin. The polymeric white couplers according to the invention meet this requirement opposite. When using these polymeric white couplers it is possible to use the Draw the required intermediate layer containing white coupler approx. 30 ffi thinner.

Another known use of white couplers is their use in emulsion layers containing color couplers, where the white coupler is combined with the color coupler competes for the developer oxidation products, and thus sensitivity and gradation of the dye images. The inventive method enables the preparation of polymeric couplers, the color coupler and white coupler units included in the desired ratio. For this purpose, the mixture of carboxyl groups is left Polymers and dicyclohexylcarbodiimide in dimethylformamide initially with the calculated Amount of one coupler, e.g. the white coupler, react and then set with the calculated amount of the other coupler, in this case the color coupler, around. In a similar manner, polymeric couplers can also be made that have two different color couplers included, e.g. 3. colorless color couplers and colored mask couplers.

Example The the following layers are cast: 1. Layer containing cyan coupler - 4.5 / u.

150 ml of a 5 so-called aqueous alkaline solution of the azo mask coupler of the following constitution are added with stirring to 1 kg of a red-sensitized photographic silver bromide iodide emulsion which contains 95 g of gelatin and 0.4 mol of silver per kg of which 92 mol% is silver bromide. In addition, 200 ml of a 6% alkaline solution of a cyan coupler of the following constitution are added.

I) this emulsion containing the coupler and mask coupler is with 25 ml of a 1% methanolic solution of 4-hydroxy-6-methyl-1,3,31,7-tetraazaindene, 30 ml of a 1f)% aqueous saponin solution and 15 ml of a 0.5 show watery Chromium acetate solution was added and poured onto the carrier.

2. White coupler-containing intermediate layer.

3rd magenta coupler containing layer - 4.2 / u.

240 ml of a 5% aqueous-alkaline solution of the colorless coupler of the formula are added to 1 kg of a green-sensitized silver bromide iodide emulsion which contains 95 g of gelatin and 0.4 mol of silver per kg of which 92 mol% is silver bromide and 120 ml of a 5% aqueous alkaline solution of the colored coupler of the formula as well as the casting additives mentioned for the emulsion for layer 1 were added.

4th gelatin intermediate layer - 1µ 5th filter yellow layer.

Colloidal silver in 2% aqueous gelatin solution (optical Density 0.6).

6. Yellow coupler-containing layer - 4.2 / u.

An unsensitized silver bromide emulsion containing 0.26 mol of silver bromide and 90 g of gelatin per kg is converted into 500 ml of an aqueous-alkaline solution of the yellow coupler of the formula as well as the usual ingredients added.

7. Gelatin protective layer - 1 / U.

Several similar materials have been produced in this way, with only in shift 2 type and application weight of the white coupler as well as the application weight of gelatin were varied, as can be seen from the table below can.

The materials were behind a red filter and a stepless Gray wedge exposed, then 15 minutes in a developer of the following composition Developed: 5 g of 2-amino-5- (N-ethyl-N-ß-methanesulfonamidoethylamino) toluene sesquisulfate monohydrate 5 ml benzyl alcohol 2.5 g sodium hexametaphosphate 1.85 g sodium sulfite sicc.

1.4 g sodium bromide 0.5 mg potassium iodide 12.5 g sodium hydroxide 34.22 g Ma2B4O7.5H2O water to 1 1.

Then continue processing as follows: Stop bath - 4 minutes 17 ml glacial acetic acid 2.94 g sodium acetate sicc.

Water to 1 1 hardness bath - 4 minutes 0. g sodium hydroxide 0.5 g sodium hexametaphosphate 9.04 g soda 20 ml formalin 37 ig water to 1 1 watering - 5 minutes bleach bath - 6 minutes 6 g sodium hexametaphosphate 42.0 g potassium ferricyanide 12.0 g potassium bromide 6 g disodium phosphate 16.0 g monopotassium phosphate water for 1 liter - 5 minutes Fixing bath - 8 minutes 15 () g ammonium thiosulphate In g sodium sulphite water on 1 1 watering - 10 minutes echo bath - 30 seconds 0. @ g sodium tetrapropylene benzene sulfonate Wet to 1,000 ml The blue-green density and the purple density of the different materials are measured behind green and red filters.

The red sensitivity of the layers is determined from the measurement curves obtained determined. This should naturally be large and in the layer containing blue-green couplers be as small as possible in the purple coupler-containing layer. Actually observed however, there is considerable dye formation in the magenta coupler-containing layer, which is primarily based on co-coupling, i.e. on coupling the purple coupler with developer oxidation products diffused into the layer containing cyan couplers is due. The co-coupling is achieved by intermediate layers containing white couplers suppressed and thus the apparent red sensitivity of the purple coupler-containing Layer lowered. The difference between true red sensitivity of those containing cyan couplers Layer and apparent red sensitivity of the magenta coupler-containing layer thus a measure for the ineffectiveness of the white coupler-containing layer. The bigger this Difference, the more effective the white coupler-containing layer.

in column 1 of the following table is the white coupler used specified. 'A' here means a white coupler according to Example 4 of the Germans U.S. Patent 1,123,913, which is given for comparison.

In columns 2 and 3, the application weights of gelatine or. egg coupler indicated in the intermediate layer containing white coupler. In columns 4 and 5 is the relative red sensitivity of the cyan coupler-containing and purple coupler-containing tubes Layer indicated, and in column 6 the difference formed therefrom.

Tabel 1 2 3 4 5 6 White application weight rel. Red- coupler in g / m2 sensitivity diff. Comp. 1 gelatine white coupl. Layer 1 Layer 3 3 5 - 36.2 33 3.2 A 3 0.6 36.9 14.4 22.5 Comp. 1 3 0.25 36.1 12 24.1 Comp. 1 1.6 0.16 36.2 12 24.2

Claims (3)

Claims: 1. Process for the production of carboxyl groups polymeric photographic coupler, characterized in that sn is a homo- or Copolymer of acrylic acid or methacrylic acid dissolves in dimethylformamide with dicyclohexylcarbodiimide implemented and then with an amino group-containing low molecular weight coupler let the connection react. 2. Carboxyl group-containing polymeric photographic couplers, prepared by the double process according to claim 1, of which a) 15 to 85 mol% of recurring structural units he following formula wherein R is hydrogen or methyl and "COUPLER" is the remainder of a low molecular weight photographic coupler which reacts with color developer oxidation products to form a colorless compound or a cyan, purple or yellow dye, and b) 85 to 15 mol% of recurring structural units of the following formula wherein R is hydrogen or methyl, contains. 3. Carboxyl group-containing polymeric photographic coupler according to claim 2, characterized in that "COUPLER" stands for the remainder of a low molecular weight white coupler stands.