EP0049399B1 - Process for producing dispersions of hydrophobic colour couplers in water, and use of these dispersions in producing light-sensitive reproduction materials - Google Patents

Description

The invention relates to a process for the production of dispersions of hydrophobic color couplers with the aid of polyurethanes and the use of such dispersions for the production of light-sensitive recording layers.

It is known to use polymers as protective colloids in the production of dispersions which contain hydrophobic substances. For example, US Pat. No. 2,272,191 describes a process for the production of color photographic layers which consists in mixing a solution of polystyrene and a polymer from the group consisting of polyvinyl acetal, polyvinyl acetate and coumarone indene in an organic solvent with a color component and the mixture to incorporate a silver halide emulsion. Disadvantages of such dispersions are that, on the one hand, energy-intensive dispersing devices are required for their production and that they have only a low storage stability.

From DE-OS 1812 578 it is known to dissolve color couplers in an emulsion copolymer of styrene / butadiene, acrylonitrile / butadiene or vinyl chloride / vinylidene chloride and to add this solution to a photographic emulsion. DE-OS 2 541 230 relates to a method for loading polymer particles, which are in the form of a polymer latex, with hydrophobic substances by mixing the latex with a solution of the hydrophobic substance in a water-miscible solvent. According to a process described in DE-AS-2541 274, synthetic latices are loaded with a hydrophobic substance by adding an aqueous latex to a solution of the hydrophobic substance in a water-miscible organic solvent or solvent mixture and then the organic solvent or solvent mixture the latex removed. DE-OS 2 835 856 describes the preparation of a latex loaded with a hydrophobic substance by mixing the substance dissolved in a water-miscible organic solvent with the latex. All these processes have in common that the hydrophobic substances are introduced into an aqueous polymer dispersion. A disadvantage of this procedure is that the resulting loaded or impregnated dispersions lose stability due to the loading with the hydrophobic substances and either form and sediment during the loading process or afterwards. As a result, the possible uses of the dispersions are considerably restricted. For example, an application of the dispersions in transparent layers, as are often used in reproduction technology, is ruled out because of the turbidity which the dispersions cause.

From DE-OS 1 597 467 a photographic material is known which contains an anionic polyurethane in one or more of its gelatin layers, in which a water-insoluble optical brightener is contained. However, the amount of the optical brightener which can be introduced into the gelatin layer with the aid of the polyurethane is limited to a maximum of 5% by weight.

According to a process described in DD-PS 138 831, polyurethanes are described in mixtures of high-boiling and low-boiling solvents for introducing photographic additives into photographic pouring solutions. A disadvantage of the process is the additional loading of the photographic layers thus produced with the high-boiling solvents. The ballast of high-boiling solvents hinders the formation of thin layers, as are required for recordings with high sharpness. In addition, the precipitation dispersion process used here according to Angew. Macromol. Chem., 72 (1978), p. 115 ff. Requires considerable amounts of auxiliary solvents if it is to lead to reasonably fine-grain dispersions. This considerably limits the economic usability of the process.

The polyurethane latexes known from European patent application 0014921 and loaded with hydrophobic compounds are produced by loading the finished polymer dispersion, the particle size of which is therefore already fixed. A disadvantage of this procedure is that the particles are enlarged by the loading process. This gives dispersions which are coarser than the starting dispersions and which therefore tend to sediment and can cloud the photographic layers.

The object of the invention is to develop a method which enables the production of stable, fine-grained dispersions of hydrophobic substances in water with the least possible technical outlay.

The invention relates to a process for the preparation of dispersions of hydrophobic substances in water by loading a polyurethane which is ionomeric and contains 4 to 180 milliequivalents per 100 g of ionic groups or groups which can be converted into ionic groups and / or which contains 1 to 20% by weight. % of alkylene oxide units of the formula ―CH ₂ ―CH ₂ ―O― built into a polyether chain, by dissolving the polyurethane together with the hydrophobic substance in an organic, water-miscible solvent with a boiling point below 120 ° C. or in a mixture the organic solvent with water in the weight ratio 50: 50 to 100 0, preferably 75: 25 to 95: 5, adding water so that a solvent / water mixture is in the weight ratio 10: 1 to 1:10 and then removing the organic solvent, characterized in that the hydrophobic substance is a color coupler and the color coupler in an amount of at least s 25% by weight, based on the polyurethane, is used.

The polyether chain can be contained laterally or in the main chain.

The polyurethanes which can be used according to the invention include polyurethanes and e.g. B. polyester polyurethanes, polyether polyurethanes containing 4 to 100 milliequivalents per 100 g of ionic groups or groups which can be converted into ionic groups and / or such polyurethanes which contain 1 to 20% by weight of ethylene oxide units of the formula ―CH incorporated within a polyethylene chain ₂ ―CH ₂ ―O― contain, where the polyether chain can be contained laterally or in the main chain.

Polyurethanes as used in the invention are known as such and z. B. in Angewandte macromolecular Chemistry, 26 (1972), pages 45 to 106; Angewandte Chemie 82 (1970), pages 53 ff; J. Oil. Col. Chem. Assoc. 53 (1970), page 363. Further descriptions of suitable polyurethanes can be found in DE-OSs 2637690, 2 642 973, 2651 505, 2 651 506, 2 659 617, 2 729 245, 2730514, 2 732 131, 2 734 576 and 2811 148.

Ionomeric polyurethanes with anionic groups are preferred. Ionomeric products which are particularly suitable for the process of the invention are described in DE-PS 1 472 746. These ionomeric products are based on polyurethanes, which are obtained from compounds with several reactive hydrogen atoms with a molecular weight of 300 to 10,000, polyisocyanates and, if appropriate, chain extenders with reactive hydrogen atoms. In the production of these polyurethanes or subsequently, isocyanate groups still present in these are reacted with a compound having at least one active hydrogen atom and at least one salt-like group or one capable of salt formation. If compounds with groups capable of salt formation are used, the resulting anionic polyurethanes are then at least partially converted into the salt form in a manner known per se.

wobei 4 bis 180 Milliäquivalente pro 100 g an ionischen Gruppen bzw. an in ionische Gruppen überführbare Gruppen verwendet werden.The term “salt-like group” means the following groups:

4 to 180 milliequivalents per 100 g of ionic groups or groups which can be converted into ionic groups are used.

The starting components for the preparation of the anionic polyurethanes are, for example, the compounds described below:

I. Compounds with active hydrogen atoms

These compounds are essentially linear and have a molecular weight of about 300 to 10,000, preferably 500 to 4,000. The compounds known per se have terminal hydroxyl and amino groups. Polyhydroxyl compounds such as polyesters, polyacetals, polyethers, polyamides and polyesteramides are preferred. The hydroxyl number of these compounds therefore corresponds to about 370 to 10, in particular 225 to 28.

As polyethers such. B. the polymerization products of ethylene oxide, propylene oxide, tetrahydrofuran, butylene oxide and their mixed or graft polymerization products, and the condensates obtained by condensation of polyhydric alcohols or mixtures thereof and the products obtained by alkoxylation of polyhydric alcohols.

As polyacetals such. B. the compounds that can be prepared from hexanediol and formaldehyde are in question. The predominantly linear condensates obtained from polyvalent saturated carboxylic acids and polyvalent saturated alcohols, amino alcohols, diamines and their mixtures are suitable as polyesters, polyester amides and polyamides.

Polyhydroxyl compounds already containing urethane or urea groups and also modified natural polyols such as castor oil or carbohydrates can also be used.

Of course, you can vary the lyophilicity. or the hydrophobicity and the mechanical properties of the process products, mixtures of different polyhydroxyl compounds are used.

11. Polyisocyanates

All aromatic and aliphatic diisocyanates are suitable as polyisocyanates such as. B. 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, di- and tetraalkyldiphenylmethane diisocyanate, 4,4'-dibenzyl diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, the isomers of tolylene diisocyanate , optionally in a mixture, preferably the aliphatic diisocyanates, butane-1,4-diisocyanate, hexane-1,6-diisocyanate, dicyclohexylmethane diisocyanate, cyclohexane-1,4-diisocyanate and isophorone diisocyanate.

III. Chain extender

• 1. Die üblichen Glykole, wie Ethylenglykol oder Kondensate des Ethylenglykols, Butandiol, Propandiol-1,2, Propandiol-1,3, Neopentylglykol, Hexandiol, Bis-hydroxymethylcyclohexan, Dioxethyldian ;
• 2. die aliphatischen, cycloaliphatischen und aromatischen Diamine wie Ethylendiamin, Hexamethylendiamin, 1,4-Cyclohexylendiamin, Benzindin, Diaminodiphenylmethan, die Isomeren des Phenylendiamins, Hydrazin, Ammoniak ;
• 3. Aminoalkohole wie Ethanolamin, Propanolamin, Butanolamin ;
• 4. polyfunktionelle Amine oder Hydroxylverbindungen wie Diethylentriamin, Triethylentetramin, Tetraethylenpentamin, Pentaethylenhexamin, Hexaethylenheptamin, Glycerin, Erythrit, 1,3-Diaminoi- sopropanol,1,2-Diaminopropanol, die monooxalkylierten Polyamine wie z. B. N-Oxethylethylendiamin, N-Oxethylhydrazin, N-Oxethylhexamethylendiamin ;
• 5. Wasser.

Chain extenders with reactive hydrogen atoms include:

• 1. The usual glycols, such as ethylene glycol or condensates of ethylene glycol, butanediol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, hexanediol, bis-hydroxymethylcyclohexane, dioxethyldian;
• 2. the aliphatic, cycloaliphatic and aromatic diamines such as ethylenediamine, hexamethylenediamine, 1,4-cyclohexylenediamine, gasoline, diaminodiphenylmethane, the isomers of phenylenediamine, hydrazine, ammonia;
• 3. amino alcohols such as ethanolamine, propanolamine, butanolamine;
• 4. polyfunctional amines or hydroxyl compounds such as diethylene triamine, triethylene tetramine, tetraethylene pentamine, pentaethylene hexamine, hexaethylene heptamine, glycerol, erythritol, 1,3-diaminoisopropanol, 1,2-diaminopropanol, the monooxyalkylated polyamines such as, for. B. N-oxethylethylenediamine, N-oxethylhydrazine, N-oxethylhexamethylenediamine;
• 5. Water.

IV. Compounds capable of salt formation

• a) Hydroxysäuren wie beispielsweise Glycerinsäure, Milchsäure, Trichlormilschsäure, Äpfelsäure, Dioxymaleinsäure, Dioxyfumarsäure, Weinsäure, Dioxyweinsäure, Zitronensäure, Dimethylolpropionsäure und Dimethylolbuttersäure, die aliphatischen, cycloaliphatischen, aromatischen und heterocyclischen Mono- und Diaminocarbonsäuren wie Glycin, a- und ß-Alanin, 6-Aminocapronsäure, 4-Aminobuttersäure, die isomeren Mono- und Diaminobenzoesäuren, die isomeren Mono- und Diaminonaphthoesäuren ;
• b) Hydroxy- und Carboxysulfonsäuren ; 2-Hydroxyethansulfonsäure, Phenolsulfonsäure-(2), Phenolsulfonsäure-(3), Phenolsulfonsäure-(4), Phenoldisulfonsäure-(2,4), Sulfoessigsäure, m-Sulfobenzoesäure, p-Sulfobenzoesäure, Benzoesäure-(1)-disulfonsäure-(3,5), 2-Chfor-benzoesäure-(1)-sulfonsäure-(4), 2-Hydroxybenzoesäure-(1)-sulfonsäure-(5), Naphthol-(1)-sulfonsäure, Naphthol-(1)-disulfonsäure, 8-Chlornaphthol-(1)-disulfonsäure, Naphthol-(1)-trisulfonsäure, Naphthol-(2)-sulfonsäure-(1) und Naphthol-(2)-trisulfonsäure ;
• c) Aminosulfonsäuren ; Amidosulfonsäure, Hydroxylamin-monosulfonsäure, Hydrazindisulfonsäure, Sulfanilsäure, N-Phenylamino-methansulfonsäure, 4,6-Dichloranilin-sulfonsäure-(2), Phenylendiamin-(1,3)-disulfonsäure-(4,6), Naphthylamin-(1)-sulfonsäure, Naphthylamin-(2)-sulfonsäure, Naphthylamin-disulfonsäure, Naphthylamin-trisulfonsäure, 4,4'-Di-(p-aminobenzoylamino)-diphenylharnstoff-disulfonsäure-(3,3'), Phenylhydrazindisulfonsäure-(2,5), Taurin, Methyltaurin, Butyltaurin, 3-Amino-benzoesäure-(1)-sulfonsäure-(5), 3-Amino-toluol-N-methansulfonsäure, 4,6-Diaminobenzol-disulfonsäure-(1,3), 2,4-Diamino-toluol-sulfonsäure-(5), 4,4'-Diaminodiphenyl-disulfonsäure-(2,2'), 2-Aminophenol-sulfonsäure-(4), 4,4'-Diamino-diphenylethersulfonsäure-(2), 2-Aminoanisol-N-methansulfonsäure, 2-Amino-diphenylamin-sulfonsäure, Ethylenglykolsulfonsäure, 2,4-Diaminobenzolsulfonsäure, N-Sulfonatoethylethylendiamin ;
• d) ferner gehören zu den Hydroxy- und Aminocarbonsäuren und -sulfonsäuren, Polycarbon- und -sulfonsäuren die (gegebenenfalls verseiften) Additionsprodukte von ungesättigten Säuren wie Acrylsäure, Methacrylsäure, Vinylsulfonsäure, Styrolsulfonsäure und ungesättigten Nitrilen wie Acrylnitril, von cyclischen Dicarbonsäureanhydriden wie Maleinsäure-, Phthalsäure-, Succinsäureanhydrid, von Sulfocarbonsäureanhydriden wie Sulfoessigsäure-, o-Sulfobenzoesäureanhydrid, von Lactonen wie β-Propiolacton, γ-Butyrolacton, die Additionsprodukte von den Umsetzungsprodukten von Olefinen mit Schwefeltrioxid wie Carbylsulfat, von Epoxycarbon- und -sulfonsäuren wie Glycidsäure, 2,3-Epoxypropansulfonsäure, von Sultonen wie 1,3-Propansulton, 1,4-Butansulton, 1,8-Naphthylsulton, von cyclischen Sulfaten wie Glykolsulfat, von Disulfonsäureanhydriden wie Benzoldisulfonsäure-(1,2)-anhydrid an aliphatische und aromatische Amine wie 1,2-Ethylendiamin, 1,6-Hexamethylen-diamin, die isomeren Phenylendiamine, Diethylentriamin, Triethylentetramin, Tetraethylenpentamin, ferner die Additionsprodukte von Natriumhydrogensulfit an olefinisch ungesättigte Verbindungen wie Allylalkohol, Maleinsäure, Maleinsäure-bis-ethylen- und -bis-propylenglykolester ;
• e) Hydrazincarbonsäuren wie Hydrazindicarbonsäuren.

1. Connections with a fully trained acidic group.

• a) Hydroxy acids such as, for example, glyceric acid, lactic acid, trichloromilk acid, malic acid, dioxymaleic acid, dioxyfumaric acid, tartaric acid, dioxy tartaric acid, citric acid, dimethylolpropionic acid and dimethylolbutyric acid, the aliphatic, cycloaliphatic, aromatic and heterocyclic mono-, alanocarboxylic, alanocarboxylic, alanocarboxylic, alanocarboxylic, alanocarboxylic, alanocarboxylic, alanocarboxylic, alanocarboxylic, alanocarboxylic, alanocarboxylic, alanocarboxylic, alanocarboxylic, alanocyclic, alanocarboxylic, alanocarboxylic, alanocarboxylic, alanocyclic, alanocarboxylic and alanocyclic mono- -Aminocaproic acid, 4-aminobutyric acid, the isomeric mono- and diaminobenzoic acids, the isomeric mono- and diaminonaphthoic acids;
• b) hydroxy and carboxysulfonic acids; 2-hydroxyethanesulfonic acid, phenolsulfonic acid (2), phenolsulfonic acid (3), phenolsulfonic acid (4), phenol disulfonic acid (2,4), sulfoacetic acid, m-sulfobenzoic acid, p-sulfobenzoic acid, benzoic acid (1) disulfonic acid (3 , 5), 2-chloro-benzoic acid (1) sulfonic acid (4), 2-hydroxybenzoic acid (1) sulfonic acid (5), naphthol (1) sulfonic acid, naphthol (1) disulfonic acid, 8-chloronaphthol- (1) -disulfonic acid, naphthol- (1) -trisulfonic acid, naphthol- (2) -sulfonic acid- (1) and naphthol- (2) -trisulfonic acid;
• c) aminosulfonic acids; Amidosulfonic acid, hydroxylamine monosulfonic acid, hydrazine disulfonic acid, sulfanilic acid, N-phenylamino methanesulfonic acid, 4,6-dichloroaniline sulfonic acid (2), phenylenediamine (1,3) disulfonic acid (4,6), naphthylamine (1) - sulfonic acid, naphthylamine (2) sulfonic acid, naphthylamine disulfonic acid, naphthylamine trisulfonic acid, 4,4'-di (p-aminobenzoylamino) diphenylurea disulfonic acid (3,3 '), phenylhydrazine disulfonic acid (2,5), Taurine, methyl taurine, butyl taurine, 3-amino-benzoic acid- (1) -sulfonic acid- (5), 3-amino-toluene-N-methanesulfonic acid, 4,6-diaminobenzene-disulfonic acid- (1,3), 2,4- Diamino-toluene-sulfonic acid- (5), 4,4'-diaminodiphenyl-disulfonic acid- (2,2 '), 2-aminophenol-sulfonic acid- (4), 4,4'-diamino-diphenylether sulfonic acid- (2), 2 -Aminoanisole-N-methanesulfonic acid, 2-amino-diphenylamine-sulfonic acid, ethylene glycol sulfonic acid, 2,4-diaminobenzenesulfonic acid, N-sulfonatoethylethylene diamine;
• d) further belong to the hydroxy and amino carboxylic acids and sulfonic acids, polycarbonic and sulfonic acids the (optionally saponified) addition products of unsaturated acids such as acrylic acid, methacrylic acid, vinyl sulfonic acid, styrene sulfonic acid and unsaturated nitriles such as acrylonitrile, of cyclic dicarboxylic acid anhydrides such as maleic acid -, succinic anhydride, of sulfocarboxylic anhydrides such as sulfoacetic, o-sulfobenzoic anhydride, of lactones such as β-propiolactone, γ-butyrolactone, the addition products of the reaction products of olefins with sulfur trioxide such as carbyl sulfate, of epoxycarboxylic acids and -sulfonic acids, Epoxypropane sulfonic acid, from sultones such as 1,3-propane sultone, 1,4-butane sultone, 1,8-naphthyl sultone, from cyclic sulfates such as glycol sulfate, from disulfonic anhydrides such as benzene disulfonic acid (1,2) anhydride over aliphatic and aromatic amines such as 1,2 -Ethylenediamine, 1,6-hexamethylene-diamine, the isomeric phenylenediamines, diethyle ntriamine, triethylene tetramine, tetraethylene pentamine, furthermore the addition products of sodium hydrogen sulfite with olefinically unsaturated compounds such as allyl alcohol, maleic acid, maleic acid bis-ethylene and-bis-propylene glycol ester;
• e) hydrazine carboxylic acids such as hydrazine dicarboxylic acids.

• a) Dicarbonsäureanhydride wie Succinsäureanhydrid, Maleinsäureanhydrid, gegebenenfalls hydriertes Phthalsäureanhydrid ;
• b) Tetracarbonsäuredianhydride wie 1,2,4,5-Benzoltetracarbonsäuredianhydrid ;
• c) Disulfonsäureanhydride wie Benzoldisulfonsäure-(1,2)-anhydrid ;
• d) Sulfocarbonsäureanhydride wie Sulfoessigsäureanhydrid, o-Sulfobenzoesäureanhydrid ;
• e) Sultone wie 1,3-Propansulton, 1,4-Butansulton, 1,8-Naphthsulton ;
• f) Lactone wie β-Propiolacton, y-Butyrolacton ;
• g) Epoxycarbonsäuren wie Glycidsäure, gegebenenfalls in Form ihrer Alkalisalze ;
• h) Epoxysulfonsäuren wie 2,3-Epoxypropan-sulfonsäure-1, gegebenenfalls in Form ihrer Alkalisalze, sowie die Addukte aus Epoxyaldehyden und Alkalihydrogensulfiten wie beispielsweise die Bisulfitverbindung des Glycidaldehyds.

2. Reactive compounds with 3 to 7 ring members which have salt-like groups or groups which are capable of salt formation after the ring opening:

• a) dicarboxylic anhydrides such as succinic anhydride, maleic anhydride, optionally hydrogenated phthalic anhydride;
• b) tetracarboxylic acid dianhydrides such as 1,2,4,5-benzene tetracarboxylic acid dianhydride;
• c) disulfonic anhydrides such as benzene disulfonic acid (1,2) anhydride;
• d) sulfocarboxylic acid anhydrides such as sulfoacetic anhydride, o-sulfobenzoic anhydride;
• e) sultones such as 1,3-propane sultone, 1,4-butane sultone, 1,8-naphthesultone;
• f) lactones such as β-propiolactone, y-butyrolactone;
• g) epoxycarboxylic acids such as glycidic acid, optionally in the form of their alkali salts;
• h) epoxysulfonic acids such as 2,3-epoxypropanesulfonic acid-1, optionally in the form of their alkali metal salts, and the adducts of epoxyaldehydes and alkali metal bisulfites such as, for example, the bisulfite compound of glycidaldehyde.

• anorganische Basen, basisch reagierende oder basenabspaltende Verbindungen wie einwertige Metallhydroxide, -carbonate und -oxide wie Natriumhydroxid, Kaliumhydroxid, Natriumcarbonat, Kaliumcarbonat, Natriumhydrogencarbonat. Ferner organische Basen, wie tert. Amine, z. B. Trimethylamin, Triethylamin, Dimethylaminethanol, Dimethylaminpropanol, Ammoniak und dergleichen.

The above acidic groups can be converted into the salt form in a conventional manner by reaction with the compounds mentioned below:

• inorganic bases, basic reacting or base releasing compounds such as monovalent metal hydroxides, carbonates and oxides such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogen carbonate. Furthermore organic bases, such as tert. Amines, e.g. As trimethylamine, triethylamine, dimethylamine ethanol, dimethylamine propanol, ammonia and the like.

The amount of the polyisocyanates is preferably selected so that all groups which are reactive with isocyanate groups react.

The reaction is optionally carried out with the use of solvents, low-boiling solvents with a boiling point below 120 ° C., such as, for example, acetone, ethanol, methanol, tert-butanol, methyl ethyl ketone, acetonitrile, tetrahydrofuran, dioxane, which are suitable, if appropriate may contain proportionate water. Water can optionally be used as a solvent for inorganic bases and compounds with at least one hydrogen reacting with isocyanate groups and at least one salt-like group or one capable of salt formation, without the addition of organic solvents.

The predominantly linear, high molecular weight anionic polyurethanes are generally obtained as clear to slightly opalescent solutions in the polar solvents mentioned. Their solids content is about 5 to 50% by weight of ionic polyurethane.

The production process for the polyurethanes used according to the invention is illustrated by the following examples.

Polymer I

• Feststoffgehalt : 35,3 %
• Viskosität (24°C) : 1 000 mPa - s
• Viskosität (24 °C) einer Probe der Lösung, die mit Tetrahydrofuran auf 30 % eingestellt wurde : 400 mPa · s.
• Sulfonatgruppengehalt : 14.1 m Äquivalent/100 g

An NCO prepolymer is prepared from 75 g (0.356 mol) of a polyester from adipic acid and 1,4-butanediol (dewatered) and 95 g (0.546 mol) of 2,4-tolylene diisocyanate at 75 to 85 ° C in 1.5 hours ( 1.78% NCO). It is dissolved hot in 1,060 g of tetrahydrofuran and a solution of 53 g (0.13 mol) of an aqueous solution of the sodium salt of N-sulfonatoethylethylenediamine in 100 ml of water is added at 50.degree. After 5 minutes, another 500 g of tetrahydrofuran are added due to the sharp increase in viscosity. A clear polyurethane-polyurea solution is obtained with the following characteristic data:

• Solids content: 35.3%
• Viscosity (24 ° C): 1 000 mPa - s
• Viscosity (24 ° C) of a sample of the solution, which was adjusted to 30% with tetrahydrofuran: 400 mPa · s.
• Sulphonate group content: 14.1 m equivalent / 100 g

Polymer II

The procedure is as described for polymer I, but acetone is used as the solvent instead of tetrahydrofuran. 1,060 g of acetone and 42.5 g (0.104 mol) of an aqueous solution of the sodium salt of N-sulfonatoethyl-ethylenediamine give a clear polyurethane-polyurea solution with a solids content of 43.6% and a viscosity of 5,700 mPa · s (24 ° C). A solution adjusted to 30% solids has a viscosity of 300 mPa. s (24 ° C). The sulfonate group content is 14.1 m equivalent / 100 g.

Polymer III

• Feststoffgehalt : 30,0 %
• Viskosität (23°C) : 2 200 mPa - s
• Sulfonatgruppengehalt : 22.2 m Äquivalent/100 g

From 400 g (0.178 mol) of a polyester of adipic acid and 1,4-butanediol (dewatered) and 47.5 g (0.273 mol) of tolylene diisocyanate (65:35 isomer mixture) an NCO prepolymer is prepared as described for polymer I (NCO = 1.68%). It is dissolved hot in 980 g of acetone and an aqueous solution of 42.5 g (0.104 mol) of the sodium salt of N-sulfonatoethyl-ethylenediamine and 75 ml of water is added at 50.degree. A pale yellow solution of a polyurethane urea is obtained.

• Solids content: 30.0%
• Viscosity (23 ° C): 2 200 mPa - s
• Sulfonate group content: 22.2 m equivalent / 100 g

Polymer IV

• Feststoffgehalt : 40 %
• Viskosität (23°C) : 60 mPa - s
• Sulfonatgruppengehalt : 19 m Äquivalent/100 g

From 550 g (1.0 mol) of a polyether based on bisphenol-A and propylene oxide and 140 g (0.08 mol) of a polyester from phthalic acid, adipic acid and ethylene glycol (all dehydrated) and 145 g (0.239 mol) of a 70% Solution of propoxylated adduct of butenediol and sodium bisulfite in toluene and 315 g (1.875 mol) of 1,6-diisocyanatohexane is produced at 100 ° C in 6.5 hours in an NCO prepolymer (4.11% NCO). 77 g (1.283 mol) of urea are added, the mixture is warmed briefly to 135 ° C. and stirred at 130 ° C. until no more NCO can be detected according to the IR spectrum. Now, with cooling, first with 290 ml of water and then mixed with 1,582 g of acetone. A clear, pale yellow colored solution of a polyurethane polyurea in acetone is obtained.

• Solids content: 40%
• Viscosity (23 ° C): 60 mPa - s
• Sulfonate group content: 19 m equivalent / 100 g

Polymer V

2200 g (4.0 mol) of a polyether based on bisphenol-A and propylene oxide and 115 g (0.053 mol) of a monofunctional polyether made from n-butanol, propylene oxide and ethylene oxide are dewatered and 160 g (0.113 mol) of 70% solution of the Sodium salt from the description of polymer IV in toluene. It is then decomposed at 60 ° C. with 1,096 g (6.30 mol) of tolylene diisocyanate (80:20 isomer mixture, deactivated with 20 mg of hydrogen chloride). Despite cooling, the temperature rises to 60 ° C. The mixture is stirred for 5 hours at 80 ° C (NCO = 4.95%) and adjusted to 70% solids with acetone, and reacted with 152 g (1.350 mol) of acetone ketazine.

• Feststoffgehalt : 36,5 %
• Viskosität: 19 000 mPa - s
• Sulfonatgruppengehalt : 7,5 m Äquivalent/100 g

900 g of this solution are now mixed with 733 ml of acetone and 95 ml of water and stirred overnight at room temperature. A clear polyurethane-polyurea solution is obtained.

• Solids content: 36.5%
• Viscosity: 19,000 mPa - s
• Sulphonate group content: 7.5 m equivalent / 100 g

A solution adjusted to 30% solids by dilution with acetone has a viscosity of 3,000 mPa · s.

Suitable water-miscible organic solvents for the process of the invention are those which are able to dissolve both the ionomeric polyurethanes and the hydrophobic color couplers. Examples of such solvents are acetone, tetrahydrofuran, dioxane, isopropanol, methanol, ethanol, methyl ethyl ketone, acetonitrile.

The amounts of hydrophobic color coupler used for the process of the invention are generally 2 to 200% by weight of hydrophobic color coupler per 100% by weight of polyurethane. Weight ratios of hydrophobic color coupler to polyurethane of 1:20 to 1: 1 are preferred.

To prepare the dispersions, water is allowed to flow into a solution of the water-insoluble hydrophobic color coupler and of the polyurethane in a water-miscible low-boiling solvent or solvent / water mixture with stirring. The solvent is separated from the resulting dispersion by distillation or by other suitable separation processes such as dialysis or ultrafiltration.

The method of the invention is excellently suitable for incorporating color couplers into color photographic recording materials. The silver halide emulsions mixed with the color couplers can advantageously be cast into thin color photographic layers in which the color couplers can react with oxidized color developer compounds, for example consisting of primary aromatic amines, to form dyes. Examples of color couplers which can be incorporated into photographic recording layers by the process of the invention come from the group of β-dicarbonyl compounds, β-ketoacetonitriles, 5-pyrazolones, pyrazolobenzimidazoles, indazolones, phenols or naphthols. Such couplers are known from the literature and are described, for example, in James, “The Theory of the Photographic Process,” chapter 12, pages 335 ff. Further in this connection, reference is made to the information contained in Res. Discl. VII, 1978 under reference number 17 643 cited documents.

The following hydrophobic color couplers are particularly suitable for incorporation into color photographic layers by the process of the invention.

Purple coupler:

Teal Coupler:

The method of the invention enables the production of stable dispersions of hydrophobic substances in water without the simultaneous use of wetting agents and energy-intensive dispersing devices. The dispersions show a surprisingly high sedimentation stability and are therefore outstandingly storable, a property that z. B. in the manufacturing process of recording layers proves to be a valuable advantage. In addition, the lightfastness of the image dyes of color photographic recording layers which contain the dispersions prepared by the process according to the invention is significantly improved. Due to the lack of the wetting agent and high-boiling solvent in the dispersions of the invention, it is also possible to keep the binder content of color photographic recording layers low, because the dispersions can also be used without the use of protective colloids, such as. B. gelatin, stable.

The process of the invention differs from known processes for the production of aqueous dispersions of hydrophobic substances, in particular in that it advantageously does not start from polymer dispersions but from solutions of the products described above, from which the particles containing the hydrophobic substances are reconstructed. The loaded particles obtained from such solutions are smaller than the particles formed by known processes by loading polymer dispersions. The use of the dispersion prepared by the process of the invention is accordingly associated with a number of advantages: Dispersions can be stored without the risk of sedimentation, they do not cause clouding of the photographic layers and in the photographic layer structure the embedded hydrophobic substances are more accessible due to the large surface area of the particles, chemical reactions.

The invention is illustrated by the following examples. Unless stated otherwise, percentages mean percentages by weight.

The following color coupler dispersions were produced:

Dispersion 1

100 g of a 30% solution of polymer I in a mixture of 90 parts of tetrahydrofuran and 10 parts of water were stirred with a solution of 15 g of coupler Y 6 in 62 g of tetrahydrofuran to give a clear solution. Subsequently, 173 g of water were added at a rate of 20 g / min and the tetrahydrofuran was then evaporated off in vacuo. The dispersion produced in this way had a solids content of 21% and an average particle size of 180 nm. The dispersion remained sedimentation-stable even after prolonged standing (100 days). Mixing the dispersion with gelatin gave completely transparent layers after pouring onto a glass plate and drying.

Dispersion 1a

The dispersion is prepared based on the method described in DD-PS 138 831 by stirring a solution of polyurethane and coupler in water and evaporating the solvent. It is a precipitation dispersion. In contrast, according to the process of the invention, water is metered into a solution of polyurethane and coupler and the solvent is evaporated off. In this case, the dispersion is formed by reversing the phase (see Dispersion 1).

To prepare the comparative dispersion, 50 g of a 30% solution of polymer I in a mixture of 90 parts of tetrahydrofuran and 10 parts of water were stirred with a solution of 7.5 g of coupler Y 6 in 31 g of tetrahydrofuran to give a clear solution. The solution was added to 86.5 g of water with stirring. The tetrahydrofuran was then removed by distillation.

The comparison gives the following results:

The precipitation dispersion process is therefore unsuitable for the production of finely divided dispersions.

Dispersion 2

The procedure was as described for dispersion 1, but polymer 11 and coupler Y 5 (dispersion 2a) and coupler Y 8 (dispersion 2b) were used. The dispersions obtained had a solids content of 22.5% (dispersion 2a) and 20.8% (dispersion 2b). The particle sizes were determined to be 156 nm (2a) and 170 nm (2b).

Dispersion 3

The procedure was as described for dispersion 1.

Polymer 111 and coupler Y 16 were used. The solids content was 20.6% and the particle size was 132 nm.

Dispersion 4

200 g of a 30% solution of polymer IV in a mixture of 90 parts of acetone and 10 parts of water were mixed with a solution of 15 g of coupler Y 11 (dispersion 4a) or 15 g of coupler Y 13 (dispersion 4b) in 50 g of acetone stirred to a clear solution. Then in a Speed of 25 g / min, 190 g of water were added and the acetone was then evaporated off in vacuo. The dispersion produced in this way had a solids content of 27% (dispersion 4a) and 28.5% (dispersion 4b).

Dispersion 5

The procedure was as described for dispersion 1. However, the color coupler M 2 was used. The dispersion obtained had a solids content of 23.2%.

Dispersion 6

The procedure was as described for dispersion 4, but using polymer II and color coupler M 1. The solids content of the dispersion was 28%.

Dispersion 7

100 g of a 15% solution of polymer I in a mixture of 90 parts of tetrahydrofuran and 10 parts of water were stirred with a solution of 15 g of color coupler C 1 in 62 g of tetrahydrofuran to give a clear solution. Subsequently, 173 g of water were added at a rate of 15 g / min and the tetrahydrofuran was then removed by dialysis against running water. A 10.2% dispersion was obtained.

Dispersions 8 to 14

• Zu 10 g des Farbkupplers wurden 30 ml Essigester und 10 ml Di n-butylphthalat gegeben. Die Mischung wurde durch Erwärmen auf ca. 45 °C gelöst. Die so erhaltene Lösung wurde zu 120 ml einer wäßrigen Lösung gegeben, die 9 g Gelatine und 0,5 g Natrium-p-dodecylbenzolsulfonat enthielt. Diese Mischung wurde unter Verwendung eines Hochgeschwindigkeitsrührers 8 Minuten lang mechanisch gerührt, wodurch der Kuppler zusammen mit dem gesamten Lösungsmittel in Form von Tröpfchen dispergiert wurde. Der in dem Tröpfchen verbliebene Essigester wird bei vermindertem Druck entfernt.

For comparison, the color couplers used in dispersions 1 to 7 were dispersed in a conventional manner as follows:

• 30 ml of ethyl acetate and 10 ml of di-n-butyl phthalate were added to 10 g of the color coupler. The mixture was dissolved by heating to about 45 ° C. The solution thus obtained was added to 120 ml of an aqueous solution containing 9 g of gelatin and 0.5 g of sodium p-dodecylbenzenesulfonate. This mixture was mechanically stirred using a high speed stirrer for 8 minutes, whereby the coupler was dispersed together with all the solvent in the form of droplets. The ethyl acetate remaining in the droplet is removed under reduced pressure.

Dispersion 15

According to Example 1 of DE-OS 2 541 274, a latex was produced and loaded with the color coupler Y 6 in the manner described. The weight ratio of color coupler to polymer was 1: 1. The particle sizes were 240 nm and 210 nm, respectively.

Comparative dispersions A, B and C

Dispersions 2, 3 and 4 of DD-PS 138 831 were reworked as dispersions A, B and C with the couplers described by their formulas. The polymer (VI) was a polyaddition product composed of 218.5 g of adipic acid-hexanediol-neopentyl glycol polyester (OH number 63), 55 g of 1,6-hexane diisocyanate and 27.8 g of sodium 1,2-diaminoethane-N-propanesulfonate used.

Dispersion A

• Purple coupler A ₁
  
• Purple coupler A ₂
  

10 g of the purple coupler A ₁ , 2 g of the purple coupler A ₂ and 5 g of dibutyl phthalate are dissolved in 100 ml of a methanolic solution of polymer VI (20% strength).

This mixture is stirred at 50 ° C in 100 ml of water with a low-speed laboratory stirrer, the low-boiling organic solvent is removed by vacuum distillation and stabilized by 100 ml of a 5% aqueous gelatin solution.

Dispersion C

• Yellow coupler C ₁
  
• Yellow coupler C ₂
  

8 g of the yellow coupler C ₁ , 1.8 g of the yellow coupler C ₂ and 6 g of dibutyl phthalate are dissolved in 100 ml of a methanolic solution of polymer VI (20% strength).

This mixture is stirred at 50 ° C in 100 ml of a 5% aqueous gelatin solution (phthaloyl gelatin). The gelatin / polymer / coupler phase is flocculated by changing the pH and the low-boiling organic solvent is thus removed.

Dispersion B

• Teal Coupler B ₁
  
• Teal coupler B ₂
  

10 g of the cyan coupler B ₁ , 2 g of the cyan coupler B ₂ and 5 g of dibutyl phthalate are dissolved in 100 ml of an acetone solution of the polymer VI (20% strength). This mixture is at 50 ° C in 100 ml Water, which contains 1 g of the color coupler B ₂ dissolved, stirred. The low-boiling organic solvent is removed by distillation.

The dispersions produced in the manner described sedimented and the non-sedimented portions had a particle size of about 1 J.Lm. Mixing the dispersions with gelatin produced cloudy layers.

Comparative dispersions D, E and F Dispersion D

93.75 g of a 32% polyurethane dispersion with a sulfonate group content of 3% and an average particle size of 75 nm were converted into a solution by adding 201 g of acetone. A solution of 15 g of coupler Y 5 in 60 g of acetone was added. 150 g of water were slowly added dropwise to the clear solution obtained from polyurethane and coupler, and the acetone was then evaporated on a rotary evaporator. The resulting stable polyurethane dispersion containing the color coupler had a particle size of 19 nm.

Dispersion E

Example A was repeated. Instead of coupler Y 5, coupler M 2 was used. The dispersion obtained had a particle size of 28 nm.

Dispersion F

Example A was repeated. Instead of coupler Y 5, coupler C 1 was used. The dispersion obtained had a particle size of 34 nm.

example 1

Dispersions 1 to 15 were mixed with samples of a silver halide gelatin emulsion which had been sensitized to blue, green or red in accordance with the color coupler introduced. The silver halide gelatin emulsion used consisted of 75 g of silver bromide iodide (iodide content 3 mol%) and 72 g of gelatin based on 1 kg of emulsion.

The emulsions prepared in this way were applied to cellulose triacetate layer supports provided with an adhesive layer and dried.

• Die einzelnen Proben wurden mittels eines Sensitometers belichtet und danach in der unten beschriebenen Weise verarbeitet. Bestimmt wurden relative Empfindlichkeit, Farbausbeute sowie Absorption und Nebenabsorption bei der Dichte 1,0. Die Ergebnisse enthält die nachfolgende Tabelle 1. Farbentwickler A
  
  Bleichbad
  
  Fixierbad
  
  Farbentwickler B
  
  Entwicklungszeiten
  
  (Siehe Tabelle 1 Seite 16 f.)
  

Photographic examination:

• The individual samples were exposed using a sensitometer and then processed in the manner described below. Relative sensitivity, color yield as well as absorption and secondary absorption at density 1.0 were determined. The results are shown in Table 1 below. Color developer A
  
  Bleach bath
  
  Fixer
  
  Color developer B
  
  Development times
  
  (See table 1 page 16 f.)
  

As Table 1 shows, the sensitivity of the color photographic layers which contain dispersions prepared in accordance with the invention is up to 4 DIN higher than that of the comparison layers. The color couplers contained in the samples according to the invention - with only minor deviations - coupled with steeper gamma. The color yields of the couplers incorporated in the manner according to the invention are significantly higher compared to the samples processed in the conventional manner. After incorporation according to the invention, the color couplers prove to be particularly reactive. The data relating to the absorption of the dyes are in no way affected by the use of the dispersions of the invention.

Example 2

Dispersions 1, 2b and 3 and comparative dispersions 8, 9b and 10 were mixed in a silver halide gelatin emulsion of the composition described in Example 1. The ready-to-pour emulsions thus obtained would now be applied to cellulose triacetate substrates provided with adhesive layers. The layer samples were exposed as indicated in Example 1, developed in the manner described below and then checked for their granularity. Two variants were used in the color development. These differed in the approach of the color developer, which had been prepared in one case with citracin acid and in the other case without this acid. It was found that higher color yields were obtained without citracin acid. The quotient Q appearing in Table 2 below results from the difference in color yields when developed with and when developed without citracin acid multiplied by 10 ² .

• F _AO = color yield when developed without citracin acid
• F _Am = color yield when developed with citracin acid
• The samples were processed in the following baths: black and white developer (pH 9.9)
  
  Reverse bath (pH 5.8)
  
  Color developer
  
  Bleaching bath (pH 5.7)
  
  
  Fixing bath (pH 6.6)
  
  Processing times
  
  

Table 2 shows the outstanding fine-grain nature of samples 1, 2b, 3 according to the invention in comparison with the corresponding comparison samples 8, 9b and 10, respectively. The quotient Q, the absolute value of which is proportional to the influence of citracin acid, was also found to be significantly lower in the samples according to the invention. This is related to the already mentioned high reactivity of the color couplers dispersed in the manner according to the invention.

Example 3

Stopbad

Bleichfixierbad (pH 7)

Verarbeitungszeiten 25 °C

The dispersions 1, 2a, 6, 7 and 15 according to the invention and the comparative dispersions 8, 9a, 13 and 14 were mixed in with the silver halide gelatin emulsions which had been sensitized accordingly to the couplers and the emulsions were poured onto a baritized paper base. The samples were then exposed as described in Example 1 and processed in the following baths.

Stop bath

Bleach-fix bath (pH 7)

Processing times 25 ° C

Die Ergebnisse werden in der Tabelle 3 wiedergegeben.

The samples are now protected without UV protection and against UV light (UV protective film which contains a hydroxybenztriazole as the absorbing substance) and exposed to the light of a xenon lamp standardized for daylight and exposed in the following way:

The results are shown in Table 3.

For comparison, samples of the above-mentioned. Dispersions containing no couplers were applied to a baritized paper base and exposed in the manner described. None of the samples (except sample 13) showed measurable yellowing. It follows from this that the surprising light-stabilizing effect of the samples according to the invention shown in Table 3 is in no way due to a filter effect which should be taken into account if the sample material yellows.

Examples 4-7

The following examples show the influence of the dispersions according to the invention on the breaking behavior of photographic materials.

A photographic emulsion layer consisting of a silver bromide emulsion, a dispersion prepared according to the invention or a comparison emulsifier, gelatin and a hardening agent was produced and dried on a prepared cellulose triacetate film support. After drying, the layer contained 20% by volume of AgBr and 30% by volume of the dispersion according to the invention or of comparative emulsifier. 36 mm wide strips of this material were 3 days in a climate of 20% r. F. adjusted at 23 ° C. The measurement was made using the drop hammer method in this climate. The test specimens are placed in loops with the emulsion layer on the outside and the energy that leads to the breakage of the film is determined. Around 100 breaking attempts were carried out, at least half of which are said to break.

The measured fracture energy values B of the layers which contain the dispersion according to the invention are compared with the fracture energy values obtained with the comparison emulsifiers. The increase in the breaking strength of the layers with the dispersions according to the invention was calculated in% using the following formula.

Vergleichsdispersionen D, E und FThe results are summarized in the following table.

Comparative dispersions D, E and F

Dispersion D

93.75 g of a 32% polyurethane dispersion with a sulfonate group content of 3% and an average particle size of 75 nm were converted into a solution by adding 201 g of acetone. A solution of 15 g of coupler Y 5 in 60 g of acetone was added. 150 g of water were slowly added dropwise to the clear solution of polyurethane and coupler obtained, and then the acetone was evaporated on a rotary evaporator. The resulting stable polyurethane dispersion containing the color coupler had a particle size of 19 nm.

Dispersion E

Example A was repeated. Instead of coupler Y 5, coupler M 2 was used. The dispersion obtained had a particle size of 28 nm.

Dispersion F

Example A was repeated. Instead of coupler Y 5, coupler C 1 was used. The dispersion obtained had a particle size of 34 nm.

Claims (2)

1. Process for the preparation of dispersions of hydrophobic substances in water by charging a polyurethane which is ionomeric and contains 4 to 180 milliequivalents per 100'g of ionic groups or groups capable of being converted into ionic groups and/or which contains 1 to 20 % by weight of alkylene oxide units of the formula ―CH₂―CH₂―O― built into a polyether chain, by dissolving the polyurethane together with the hydrophobic substance in an organic water-miscible solvent having a boiling point below 120 °C or in a mixture of the organic solvent with water in a weight ratio of 50 : 50 to 100 : 0, adding water, so that a solvent/water mixture having a weight ratio of 10 : 1 to 1 : 10 is present and then removing the organic solvent, characterised in that the hydrophobic substance is a colour coupler and the colour coupler is used in a quantity of at least 25 % by weight, based on the polyurethane.

2. Use of the dispersion prepared by the process according to Claim 1 for the production of colour- photographic recording materials.