Light-sensitive photographic material with cationic polyurethane mordant
United States Patent [1 1 Rosenhahn et al.  
 Bergthaller, both of Cologne, Germany [73] Assignee: Agfa-Gevaert Aktiengessellschaft,  
 Leverkusen, Germany [22] Filed: Mar. 21, 1974 [21] Appl. No.: 453,304  
 [30] Foreign Application Priority Data Mar. 27, 1973 Germany 2315304 [52] U5. Cl 96/84 A; 96/57; 96/84 R; 96/74; 96/100; 96/114 [5l] Int. Cl G03c 1/84 [58] Field of Search 96/84 A, 57, 114, 100, 96/74 [56] References Cited UNITED STATES PATENTS 8/1968 Keberle et al. 96/114 2/1974 Balle et al 96/1 14.2  
 Primary Examiner-Ronald H. Smith Attorney, Agent, or FirmConnolly and Hutz [451 Apr. 15, 1975 [5 7] ABSTRACT A photographic material comprising at least one silver halide emulsion layer and at least one anionic organic compound such as dyes or color couplers and as mordant therefor at least one water soluble or water dispersible cationic polyurethane which has an average molecular weight of 10,000 to 60,000 which contains repeating units, in polymerized form, which are derived from (a) an alkanediol component of which at least 80 mols is one or more amino containing diols of the formula and up to 20 mols is one or more diols of the formula I-iO R OH and (b) a diisocyanate component selected from the group consisting of aliphatic, cycloaliphatic and/or aromatic diisocyanates, but at least 40 mol must be aliphatic or cycloaliphatic and not more than 20 mols can be cycloaliphatic; at least 40% of all the tertiary amino groups in the polyurethane being quaternized in in which formulae R and R the meanings as defined hereinafter. The mordants are photographically inert and may be used with advantages in any photographic layer.  
 7 Claims, No Drawings LIGHT-SENSITIVE PHOTOGRAPHIC MATERIAL WITH CATIONIC POLYURETHANE MORDANT This invention relates to a light-sensitive photographic material in particular to a color photographic material comprising at least one silver halide emulsion layer which contains cationic polyurethanes which are soluble or dispersible in water for use as mordants to fix diffusible anionic organic compounds such as dyes or color couplers.  
  It is known to produce color photographic images by chromogenic development, i.e. by a process in which silver halide emulsion layers which have been exposed imagewise are developed by means of suitable color forming developing agents, so-called color developers, in the presence of suitable colour couplers. in which process the oxidation product of the developing agents which is produced in the areas corresponding to the silver image reacts with the colour coupler to form a dye image. The color developers employed are usually aromatic compounds which contain primary amino groups. in particular those of the p-phenylenediamine series.  
  The materials used for producing multi-color photographic images by the subtractive process are generally light-sensitive materials which contain at least one red sensitized. one green sensitized and one blue sensitive silver halide emulsion layer, and chromogenic development in the presence of colour couplers suitable for producing the various partial colour images results in these layers in a cyan partial image, a magenta partial image and a yellow partial image, and these partial images superimposed on each other produce the multicolored image.  
  In order to obtain very natural color reproduction and sharp images, the color couplers for the various partial images of the multicolored image are generally incorporated in a diffusion-resistant form in the various appropriately sensitized emulsion layers. The color couplers used may be, for example, hydrophobic color couplers which are dispersed in the emulsions as a heterogeneous phase in the form of a solution in a low boiling solvent. optionally with the aid of a high boiling coupler solvent which is immiscible with water (a socalled oil forming solvent) or they may be color couplers containing groups which render them soluble in alkaline media (acid groups) and a longer organic molecular group, and these couplers are then added to the emulsions in the form of an aqueous alkaline solution.  
  The fineness of grain which can be achieved and hence the resolving power of the material depend to a major extent on the diffusion resistance of the colour couplers and of the dyes produced from them. The results previously achieved do not come up to expectation in every respect so that it would appear desirable to improve the resolving power.  
  it is therefore significant that in layers which contain dissolved anionic color couplers which have a slight tendency to diffusion, the addition of cationic mordants is capable of improving the sharpness of the dye image formed in the colour developer, as described e.g. in British Pat. No. 1,318,492.  
  Colored layers which are decolorized in the course of development are frequently used in photographic materials, for example it is customary to cover the back of roll films and flat flims with colored gelatine layers. These layers are used not only to reduce the tendency of the film to curl up but also to prevent the formation of a reflected light halo by absorbing as completely as possible any light which is not absorbed by the emulsion layers during exposure. This effect can be improved by applying the coloured layer not to the back of the support but immediately underneath the lowest emulsion layer so that no back reflection can occur from the film support. In some cases, it is also necessary to coat the emulsion layer with a layer of dye in order to filter any unwanted light off from the emulsion.  
  Filter layers play a particular role in color photographic multilayered materials. For example a yellow filter layer can be arranged underneath a blue sensitive layer to ensure that the layers underneath the blue sensitive layer, which have beensensitized to green or red light but still have a certain intrinsic sensitivity to blue light, will be protected against blue light. It is also known that the sharpness and reproduction of green in areas of strong exposure can be improved if a filter layer containing a dye which absorbs green light is arranged between a green sensitized layer and a red sensitized layer underneath it.  
  The dyes used in antihalation and filter layers must satisfy numerous requirements, for example they must have satisfactory absorption properties and be completely and irreversibly bleached in the usual photographic baths. They should also be readily soluble or dispersible so that they can be introduced in sufficiently high concentrations in the layers but at the same time they must be firmly fixed in the layer in which they are required so that they will not diffuse into adjacent emulsion layers. Dyes contained in the layer applied to the back of the support are also required to be diffusion resistant because this layer is also liable to come into close contact with the emulsion layer, e.g. in roll films or in stacked flat films. The diffusion resistance of the dyes must be maintained even under extreme conditions such as elevated temperature and moisture.  
  The use of basic or cationic mordants for fixing diffusible anionic organic compounds in photographic layers is a known measure. The term photographic layers is used in this context to mean quite generally any bonding layers, emulsion layers, interlayers, filter layers or covering layers which contain a hydrophilic colloid such as gelatine.  
  It has already been proposed to introduce anionic organic compounds such as dyes in a diffusion resistant form into the layer by adding guanidines, polymers which contain amino groups and similar basic compounds to gelatine solutions of the dyes or to fix the dyes by introducing longer fatty acid groups into the dye molecule. Such methods, however, usually have the effect of reducing the solubility of the dyes so that they become difficult to introduce into the layers or of deleteriously affecting the tendency to decolorization of the layers or in some cases excessive fogging is produced in the adjacent emulsion layers, for example when long chain quaternary ammonium salts are used as mordants for acid dyes. These properties are particularly disadvantageous if mordants are used in the photographic emulsion layers.  
  Cationic mordants such as those described in British Pat. Specification No. 1,297,324 and French Pat. Specification No. 2,131,304 and in US. Pat. No. 2,882,156, for example, have a strong tendency to separate by flocculation if they are dispersed in gelatine together with dyes or color couplers so that they can only be used in relatively low concentrations and only in intermediate layers. The polymeric mordants described in U.S. Pat. No. 2,882,156 in addition cause an undesirable increase in the viscosity of the mixtures with aqueous gelatine solutions and relatively strong discoloration of the aqueous mixture.  
  Polyvinyl pyridines are generally unsuitable for emulsion layers which contain silver halides because they have aa pronounced photographic activity which is particularly noticeable in more highly quaternized products.  
  The homopolymers or copolymers of maleic acid imides containing quaternary ammonium groups which have been described in French Pat. Specification Nos. 2,003,003; 2,003,004 and 2,003,006, in common with the classes of compounds mentioned above, are characterised by the fact that they are photographically inert only if they have a sufficiently high molecular weight, if they do not contain any low molecular weight components and if they do not split off any low molecular weight components in the course of storage. The main photographic effects of the low molecular weight components are fogging of silver halide emulsions, undesirable changes in sensitivity, changes in the form of gradation and reduction in the stability of the photographic materials, and in practice these components with low molecular weight are removed from those with a high molecular weight by expensive purification methods as described e.g. in US. Pat. No. 3,488,706.  
  It is well known in the art that polyurethanes which have a latex character are used as gelatine plasticizers to improve the physical properties of photographic layers. When used for this purpose, the known cationic polyurethanes again manifest the difficulties mentioned above as regards their compatibility with silver halide emulsions and there have therefore been numerous attempts to reduce the proportion of low molecular weight polyurethane units by employing certain methods of polymerisation which generally include the use of a reactive polymer with diisocyanates and suitable ionic chain lengthening agents, for example as described in German Pat. Specification No. 1,260,974 and in British Pat. Specification 1,161,619 and US Pat. No. 3,397,989. Although the high polymer polyurethanes produced in this way are photographically inert, they are not suitable for use as photographic mordants because they contain only a very small proportion of cationic groups.  
  The use of water-soluble cationic polyurethanes as mordants in photographic layers is already known per se. The substances proposed in German Pat. Specification No. 928,268 to effect diffusion resistant incorporation of anionic organic compounds in photographic layers include, among others, polyurethanes of diols which contain tertiary nitrogen atoms and diisocyanates, which polyurethanes are water soluble at least in the quaternized form.  
  This class of compounds, however, has not become established in photographic practice because it has numerous disadvantages, in particular the fact that most representatives of this class of compounds are too sparingly soluble or not photographically inert even at higher molecular weights. It has been found, for example, that basic polyurethanes obtained by reacting any N-alkyl-dialkanolamines with aromatic diisocyanates alone form hard, brittle products which are difficult to dissolve in water even when quaternized and can therefore be introduced into gelatine without undue difficulty only if they have been polymerized only to a fairly low degree and moreover they tend to separate by flocculation in the presence of multivalent anions.  
  Although the basic polyurethanes prepared from N- alkyl dialkanolamines and commercially available alicyclic diisocyanates are in their quaternized form generally more readily soluble and very compatible with gelatine and do not have an undue tendency to flocculation, they are not photographically inert and they cause an increase in fog and decrease in stability in silver halide emulsions with which they come into contact. Quaternized basic polyurethanes which consist substantially, that is to say generally to an extent of more than to 7c, of N-methyldiethanolamine and any diisocyanates, are not photographically inert even at high molecular weights.  
  Cationic polyurethanes prepared from N-alkyldialkanolamines which contain more than 2 carbon atoms in the alkanol component, e.g. polyurethanes of N-methyl-bis-Z-hydroxy propylamine and any diisocyanates, are difficult to dissolve and photographically not inert.  
  It is therefore an object of this invention to provide photographically inert mordants for anionic organic compounds which satisfy the numerous requirements in practice and can be used in any photographic layers such as emulsion layers, intermediate layer, filter layers and covering layers.  
  It has now been found that cationic polyurethanes which are soluble or dispersible in water and have an average molecular weight of 10,000 to 60,000 and which have been prepared by the polyaddition of certain N-alkyl-dialkanolamines and diisocyanates selected as described below followed by quaternisation of at least 40 7r and preferably 70 to 7c of tertiary amino groups present with a suitable quaternizing agent have excellent photographic properties.  
  This invention relates to a light sensitive photographic material comprising at least one silver halide emulsion layer containing anionic organic compounds and a water-soluble or water dispersible cationic polyurethane as mordant for the anionic organic compounds, characterised in that the cationic polyurethane has an average molecular weight of 10,000 to 60,000 and a degree of quaternization of at least 40 7c and contains an alkanediol A which mainly contains amino groups alternating with a diisocyanate D, wherein at least 80 7: of the groups A consist of alike or dissimiliar structural units of formula I R 1L1 -O-CH CH -CH -CH -O- I of which at least 40 7c and preferably 70 to 95 7c are in the quaternized form (formula 11) O-CH CH -III- CH CH O- II and not more than 20 7c of the groups A consist of alike or dissimiliar structural units of the formula III -OR;;-O  
 in which formulae R, represents alkyl containing 2 to and in particular 3 to 6 carbon atoms, preferably n-butyl; R represents alkyl containing I to 4 carbon atoms, preferably methyl or ethyl; X represents a monovalent anion, preferably an aliphatic or aromatic sulfonic acid. a lower aliphatic carboxylic acid or an acid sulfuric acid alkyl ester containing 1 to 4 C atoms, e.g. CH SOJ, CH -C,,H =,SO CH=,COO, cH .,oso.,-, C H OSO or C H OSO and R represents an aliphatic hydrocarbon chain optionally interrupted by O, S, or NCH group; and the groups D represent structural units of formula IV in which R represents a saturated aliphatic or cycloaliphatic hydrocarbon group or an aromatic hydrocarbon group, at least 40 7r and preferably 70 to 90 7( of all the groups R being saturated (aliphatic or cycloaliphatic), R. preferably having the meaning (CH and not more than 7c of the groups R being cycloaliphatic.  
  The building up of the cationic polyurethanes from selectively differing N-alkyl-dialkanolamines or mixtures thereof with other alkanediols and various diisocyanates can be widely varied by choice of the concentration ratios, the sequence in which the individual reactants are added and the reaction temperature employed.  
  The N-alkyl-dialkanolamines which are suitable for synthesizing the cationic urethanes according to the invention are short chain aliphatic dialkanolamines, preferably diethanolamines of the folowing formula la #1 II H0-CH -CH -H-CH -CH -OH in which R has the meaning indicated above.  
  According to the invention. up to 20 mols 7: of these N-alkyl-diethanolamines may be replaced by other alkanediol compounds, e.g. with those of formula Illa HOR OH lllu in which R;, has the meaning already indicated above.  
  Diisocyanates suitable for preparing the cationic polyurethanes according to the invention have the formula [Va OCN--R,-NCO lVu in which R, has the meaning already indicated. R may in particular denote a divalent aliphatic group containing 4 to 9 carbon atoms, preferably a hexamethylene, 2,2,4-trimethylhexamethylene or 2,4,4-trimethylhexamethylene group. Up to 20 of the diisocyanates used for preparing the polyurethanes according to the invention may contain cycloaliphatic groups R,, e.g. groups of the following structures:  
  CH QE-CH or -CH CH CH Up to 60 7( of the diisocyanate used may also contain aromatic groups, e.g. a divalent aromatic group containing 6 to 15 carbon atoms, preferably a benzene, naphthalene, diphenyl methane or substituted diphenylmethane group.  
  Preparation of the cationic polyurethanes is carried out by methods known in the art such as those described in Houben-Weyl Volume 14, part 2, pages 57 98, followed by quaternization with a suitable quaternizing agent.  
  Basic polymers with an average molecular weight of 10,000 to 60,000 used as starting materials for the process according to the invention may also be obtained by the following methods:  
 1. An equimolar or slightly less than equivalent quantity (97 to 100 7c) of an aliphatic diisocyanate is gradually added to a N-alkyl-diethanolamine. The reaction product is then heated at 100 to C to produce resinous polyurethanes with an average molecular weight of between 10,000 and 60,000. the average molecular weight increasing as the molar ratio of the diisocyanate (D) to alkanediol (A) approaches 1. If desired, a portion (up to 20 mols 7r of the alkylethanolamine may be replaced by an equimolar quantity of compounds of formula III a which contain active hydrogen atoms.  
 . A basic prepolymer with hydroxyl terminal groups is obtained by adding a less than equivalent amount of aliphatic diisocyanate to a N- alkyldiethanolamine either without solvent or in an aprotic solution. This prepolymer can be chain lengthened by adding a specified less than equivalent amount of a more highly reactive aromatic diisocyanatc in aprotic solvents at 60 to |00C, polyurethanes with average molecular weights of 10,000 to 60,000 being obtained.  
  Here again, a portion of the N-alkyl-diethanolamine may if desired be replaced by equimolar quantities of compounds of formula [I] a which contain active hydrogen atoms.  
  The cationic polyurethane according to the invention may in addition contain up to 5 7c of impurities which need not be removed when commercial starting compounds are used, for example N-alkyl-diethanolamines of Formula I occasionally contain N-alkylethanolamines. These impurities do not affect the photographic properties of the polyurethanes according to the invention provided they do not amount to more than 5 7: of the total quantity of polymer.  
  The starting compounds which are suitable for preparing the polyurethanes according to the invention are purified by distillation and dried in order to restrict as far as possible the side reactions which normally accompany the polyaddition of diisocyanate and diols, such as branching of the chains due to the incorporation of biuret groups and the like.  
  The choice of a suitable cationic polyurethane used in photographic layers according to the invention to fix anionic organic compounds such as dyes and couplers and in particular conventional anionic colour couplers, white couplers, masking couplers or DIR couplers and filter dyes, screening dyes. antihalation dyes. white toners and UV absorbents can easily be determined by a few laboratory tests carried out as part of the process according to the invention.  
  If a hydrophilic or a more hydrophobic cationic polyurethane is required, the polyurethanes according to requirements by varying the groups R R and R of starting compounds I and ll and the degree of quaternization in accordance with the rule that cationic polyurethanes according to the invention in which groups R and R in the structural units of formula ll together contain 4 to 6 carbon atoms are more hydrophilic in their properties than cationic polymethanes according to the invention in which the total number of carbon atoms in groups R and R is more than 6.  
  If the number of carbon atoms in the group R does not exceed 6 and the proportion of aromatic diisocyanate is less than 25 7t of the total quantity of isocyanate, the first mentioned cationic polyurethanes according to the invention are soluble in water as soon as I the degree of quaternization is higher than 50 7t and readily compatible with hydrophilic binders such as gelatine. The solubility in water may, however, in all cases be improved by salt formation of the unquaternizcd basic N-atoms in the groups of formula I by means of acids so that the cationic polyurethanes according to the invention can be incorporated as homogeneous dispersions in gelatine.  
  The polyurethanes according to the invention are distinguished by excellent properties, namely l. They are photographically inert if in accordance with the invention they are used in photographic materials in the presence of anionic organic compounds, they cause no increase in the development fog. no change in sensitivity and no change in gradation and they have no deleterious effect on the stability of the halide emulsions. They have no undesirable effect on the physical properties of photographic materials and in particular the tendency of the gelatine to swell is not deleteriously affected. Furthermore. the viscosity of the casting solution is increased only to an insignificant extent by the addition of the mordants, and the mordants are compatible with gelatine in practically unlimited quantities.  
 3. ln contact with anionic organic compounds, they have a surprisingly low tendency to flocculate and even colour couplers which have the character of anionic wetting agents due to the incorporation of groups which render them diffusion resistant are compatible with the mordants according to the invention.  
 4. The mordants render anionic organic compounds diffusion resistant at a pH of 5 to 8 and liberate them reversibly under the conditions of development at a pH of 10 and upwards so that diffusible anionic organic compounds can easily be removed completely from the photographic material by washing while diffusion resistant anionic compounds, e.g. the dye formed in the process, are again fixed in a finely divided form in the photographic material after completion of alkaline development.  
 5. The mordants enable anionic organic compounds to be fixed in such high concentrations that excessive loading of the hydrophilic colloid layer by the mordants can be avoided.  
 6. Preparation of the high molecular weight polyurethane mordants according to the invention which have an average molecular weight of 10,000 to 60,000 does not require any complicated methods of purification.  
 The quaternization products according to the invention may be precipitated from solutions which contain lower alcohols by means of aprotic solvents and thus be freed from impurities. They are insoluble in most aprotic solvents, especially if they have a higher degree of quaternization, but they dissolve in water or in mixtures of lower alcohols with certain aprotie solvents such as ethyl acetate, methylene chloride, ethylene chloride or acetone and in this form they can be dispersed or dissolved in gelatine.  
 Examples of the cationic polyurethanes according to the invention are given below Compound Starting compound Ia Starting compound Iva Recurrent units of formula II OH CH obtained by quaternization F 2 2 OCNR -NCO Aromatic R1 on on -on (cycle) ali- H 2:  
 2 2 phatic e anave O-CH C: -1 ;CH CH O- diisocyanate R X R 11101 R mol R :nol R )6 degree of waternization 2%) &#39;l C r: nv 1 H cn l (c.. 0.2a I err sc 8O n u if O- ,8 c 11 C M CO 9O 9 1 0.8 0.2 CZI CH SO 8O Lt II u o u 1 r H I O. 0.09 0 h; C H OSO 8O 2 1 0.9 0.09 n-C E n-C H OSO 8O 6 &#39;1 1 u o o 8 n I 1 n O. J u 2.0, 11 0 11 n C H OO O 0.9 0.2 C H 0 11 0.30 8O 8 1| 1 II 0 8 II o &#39;1 ll 9 u 1 u 0 u 1 II II 90 &#39;1 1 u 0 n 7 :i n 90 1 u 0 II 15 n n 90 1 e .8 0.18 55 residual amine as acetate 5 1 n 0 8 II 0 n it M; II 1 H 0 6 H I! II Site compounds marked with are not claimed Compounds marked with are not claimed.  
  cording to the invention are described in detail below:  
 Compound 1:  
  161 g of n-butyldiethanolamine (1 mol) are added dropwise at 80C to 134.5 g of hexamethylene diisocyanate (0.8 mol) with stirring. 30.2 g of hexamethylene diisocyanate (0.18 mol) are then added all at once and the mixture is heated to 140C for 3 hours with stirring. After cooling, the basic polyurethane is dissolved in 500 ml of ethylene chloride. 88 g of freshly distilled dimethyl sulfite (0.8 mol) in 200 ml of ethanol are then added. The mixture is then heated at 90 to 95C for 16 hours with stirring. The resulting polymer is then precipitated with 1000 ml of acetone.  
  415 g of an 80 7! quaternized polyurethane having an average molecular weight of 10,000 to 20,000 are obtained.  
  The polyurethane obtained is then dissolved in the quantity of water required to produce a total volume of solution of 2,000 ml. The solution obtained in this way is ready for use and can be incorporated by the usual methods in the mixtures ready for casting photographic layers.  
 lf quaternisation is carried out using 88 g of methyl Continued Compound .Starting compound Ia compound I73 Recurrent units of formula II obtained by. quaternization 2 -2&#39; OCNR, NCO Aromatic R1 n diiso- 1- l l l a z 232 1 benave O.-CH CH NGH CH -O l diisocyanate R X 11101 R. mol R mol R degree of nuater- 1 A 4 2 nizetion (H .2 1 Q021 o .8 o .18 0 8 c a oso 80 0 +5 ca (ca 0.9 (oa 0.8 Q. 0.18 0 c H 080&#39; 70 residual amino 5 2 5 O 1 2 6 2H5 2 5 5 converted into acetate 94 ca -(ca 0.9 (CH 0.8 Q- 0.18 c c oso&#39; 58 residual amine 3 5 o 1 2 6 2H5 2A5 5 converted into 5 ac etete 5 CH -(CH 0.75 0.8 0.18 0 8 0 8 080; 80  
 46 GEL-(CH 0.75 0.8 0.18 C H C 050 38 residual amine 9 0 3 5 O 25 2H5 5 converted into 3 acetate 47&#39; CH (CH 0.75 C 0.8 0.18 C C O50 5O residual amine 5 CH 5 O 25 9 2H5 2H5 5 converted into 5 acetate l-B CH5-(CH2)5 0.75 0.6 0. 8 CH3 011550 80 a u r Q9 (3.. (011 0.5 (0H 0.9 0 11 0 8 080 90 CH3 0.5 5 g-( 0.5 0.8 Q. 0.18 8  
  CH; 0-5 5 g-( 0.5 0.8 o .18 CH 011 80 80 52&#39; 08 1 -C H 0 .8 0 18 CH 011 805 80 55&#39; C55 1 -(CH2)6 0.8 0.18 CH (cH n-G H OSO; 8O &#39;2 CH 1 0 98 c 8 C H OS 0 9o methanesulfonate, a reaction time of 6 hours is suffcient instead of the 16 hours indicated above. Substantially the same cationic polyurethane is then obtained. Compound 3:  
  134.5 g of hexamethylene diisocyanate (0.8 mol) are added dropwise to 161 g of n-butyl diethanolamine (1 mol) in 200 ml of anhydrous ethyl acetate at to C with stirring and the reaction mixture is then heated for a further 30 minutes at C. A solution of 32 g of 1,4-diisocyanatobenzene (0.2 mol) in 200 ml of anhydrous ethyl acetate heated to 60C is then added with vigorous stirring in the course of 5 minutes. The viscosity of the solution rises sharply as the temperature is raised to 75C. The solution is then boiled under reflux for 3 hours with stirring. 88 g of freshly distilled dimethyl sulfite (or methylmethane sulfonate) are then added and the reaction mixture is heated under reflux for 16 hours (or 6 hours).  
  The solution ready for use is prepared by adding ethanol to make the total volume up to 200 ml. To prepare a solution ready for use, the cationic polymer may be freed from ethyl acetate adhering to it by precipitating it with 500 ml of acetone and then dissolving it in water.  
 Compound 29:  
  94.5 g of commercial trimethylhexamethylenediisocyanate (0.45 mol) consisting of about 50 71 of 2,2,4-trimethyland about 50 7: of 2.4.4-trimethyl-hexamethylene diisocyanate are added dropwise to 161 g of n-butyl-diethanolamine (1 mol) at 90 to IC with stirring and the reaction mixture is then heated for one hour at 100C. A solution of 75.6 g of hexamethylene diisocyanate (0.45 mol) in 100 ml of ethyl acetate is then added dropwise while the temperature is kept at 90C, and the reaction mixture is then heated for one more hour. 14.4 g of l,4-diisocyanatobenzene (0.09 mol) in 100 ml of ethyl acetate are then added with vig orous stirring and the reaction mixture is heated to 90C for 4 hours. After dilution with 250 ml of ethanol. 123 g of diethylsulfate (0.8 mol) is added dropwise at 60C and the reaction mixture is then heated under reflux after 8 hours.  
  To prepare a solution ready for use, the reaction mixture is stirred into 1000 ml of acetone, and 300 ml of petroleum hydrocarbons (b.p. 60-l0OC) are added. The polymer which separates in the form of a paste is then stirred up twice with 1000 ml portions of acetone and then taken up with 500 ml of ethanol. The volume is then made up to 2,000 ml with water.  
  As already mentioned above, color couplers with various constitutions which contain one or more acid groups such as sulfonic acid or carboxyl groups can be incorporated in a diffusion resistant form in layers of hydrophilic binders such as light sensitive silver halide emulsion layers or light insensitive layers of binder adjacent thereto bymeans of the mordants according to the invention. These color couplers may in general be the usual colorless compounds which react with oxidation products of color developing agents to form azomethine dyes or azo dyes, provided they contain at least one acid group. Reference may be made in this connection to the article by W. Pelz entitled Farbkuppler in Mitteilungen aus den Forschungslaboratorien der Agfa Leverkusen-Munich, Volume lll, page 111. Thus, for example the substances used as cyan couplers are generally compounds which are derived from phenol of a-naphthol, the magenta couplers are generally compounds derived from 2-pyrazolinone-5 or indazolone and the yellow couplers are generally derived from B-keto-carboxylic acid derivatives, e.g. from benzoyl acetanilide. It is customary to use couplers which are not substituted in the coupling position although couplers in which the coupling position is occupied by a substituent which is split off in the reaction with oxidation products of the developer, for example to liberate a development inhibitor, may also be used. It should be mentioned here that the diffusion resistance of couplers which undergo coupling to give rise to a colorless compound, that is to say so-called white couplers which are used e.g. to correct the color gradation or prevent faulty diffusion of developer oxidation products can also be improved with the aid of the mordants according to the invention.  
  It is advantageous to start with acid couplers which are already fairly resistant to diffusion even in the absence of the mordants according to the invention, i.e. couplers which in addition to the acid group contain a molecular group which renders them resistant to diffusion, generally a longer hydrocarbon chain. It has been found that the additional use of the mordants according to the invention substantially improves the diffusion resistance of such couplers, this improvement showing itself in a considerable increase in the sharpness of reproduction of the image. Diffusion of the couplers into adjacent layers and especially lateral diffusion of the resulting dye within the layer in the course of photographic processing and subsequent storage of the photographic material are effectively prevented.  
  Examples of couplers containing acid groups are given in the following table of formulae:  
 ea n-0 11 I 3 @CO-NH- so a so a 5 00-11-011 --m1-co-c a 1 coon coon 21e 33 a 6 --CO-NH NH N l H clo CH-SOH 14* 29 C H -CO-HH--CH -co-&#39;ca -co-na NHCO-CH -CO C OOH COOH C OOH COOH  When cationic mordants and couplers which contain acid groups are mixed in aqueous solution, a complex which is insoluble at all pH values is generally formed, and a homogeneous mixture which does not floeculate can be obtained only if certain procedures are employed.  
  It has unexpectedly been found that the addition of couplers which contain acid groups to gelatine solutions which contain the cationic polyurethane mordants according to the invention is not critical and various methods may be employed.  
  The cationic mordants are generally added to the silver halide emulsion in the form ofa 10 to 25 71 solution in an aqueous gelatine solution which contains at least 1 &#34;/1 of gelatine. The acid coupler is then added in the form of an aqueous. optionally alkaline solution although a fine dispersion can also be obtained by reversing the sequence or adding couplers and mordants simultaneously. Emulsions ready for casting generally contain the mordant in quantities of l to I00 g/kg. preferably 10 to g/kg. The color couplers are used in the usual quantities.  
  The mordants according to the invention may also be used to incorporate dyes of various constitutions which contain one or more acid groups such as sulfonic acid or carboxyl groups in a diffusion resistant form in hydrophilic binder layers. Dyes suitable for this treatment are mainly those from the classes of oxonoles. styryl dyes, triphenylmethane dyes, merocyanines, azo dyes, etc.. The following are examples of suitable dyes:  
 as iron III-complex The polyurethanes according to the invention are particularly suitable for fixing yellow dyes in yellow filter layers because for this purpose mordants must be particularly cfficient and because the concentration of yellow filter dyes is generally higher than that of other filter dyes used in filter layers so that yellow filter layers require mordants which can fix a high concentration of acid yellow dyes. The polyurethane mordants according to the invention are superior also in this respect to the mordants known in the art so that yellow filter layers containing them can be prepared in a thickness which is equal to or not substantially greater than the usual thickness, for example of yellow filter layers containing colloidal metallic silver.  
  The polyurethanes according to the invention manifest equally good properties when they are used together with other anionic dyes mentioned above such as masking dyes, dyes for improving the minimum density in reversal films, antihalation dyes, white toners and UV absorbents in photographic materials.  
  It has surprisingly been found that when the polyurethane mordants according to the invention are introduced as homogeneous phase into the binder, the casting solutions which they form with the classes of dyes or couplers mentioned above are resistant to digestion and undergo a slight increase in viscosity only if a polyurethane with an average molecular weight of more than 40,000 as defined above has been used. This viscosity increasing effect can, however, be diminished by dispersing the mordant in the binder solution as a heterogeneous phase consisting of finely divided discrete particles. It has been proposed in the literature to disperse the mordant either together with a crystalloid or together with a homopolymer or copolymer of acrylic or mcthacrylic acid. ln all such cases, a part of the cationic groups is either enclosed inside the phase or saturated by salt formation so that the full number of cationic groups is no longer available for mordanting purposes. It is therefore necessary to increase the total quantity of mordant used, with the result that the layer is excessively loaded with foreign substances, becomes less permeable to water and is altered in its swelling properties and hardenability. It has surprisingly been found that polyurethanes according to the invention which have a hydrophobic character as defined above or with an average molecular weight of more than 40,000 can easily be introduced into the hydrophilic binder in a form in which they are resistant to digestion by means of mixtures of alcohol with certain aprotic solvents such as ethyl acetate, methylene chloride, ethylene chloride or acetone and that the resulting dispersion which contains finely divided discrete particles in not reduced in its mordanting effect, with the result that the concentration of the mordants need not be increased.  
  The antihalation and filter layers are prepared in the usual manner by casting the gelatine solution of dye and mordant on a photographic material. A wetting agent, preferably a neutral wetting agent such as saponin, may be added so that the solution can be cast more uniformly. The pH of the casting solution is adjusted by the usual methods to a value comparable to that of the emulsion used. The proportions of dyes, mordants,  
 binders, hardeners and wetting agents may be varied I within wide limits and depend on the particular purpose for which the photographic material is intended. The methods used to find the optimum proportions are well known in the Art and need not be described here.  
  The usual, preferably transparent materials may be used as supports for the color photographic materials according to the invention, e.g. foils of cellulose esters, polycarbonates, especially those based on bishydroxyphenyl alkanes, polyesters, especially polyethylene terephthalate, etc.. Glass and paper may, of course, also be used as supports.  
  The emulsions for the light sensitive layers of the material according to the invention may be emulsions of silver halides such silver chloride, silver bromide or mixtures thereof. optionally with a small silver iodide content of up to 10 mols 7!, in one of the conventional materials used as binders such as protein, in particular gelatine, polyvinyl alcohol, polyvinyl pyrrolidone. cellulose derivatives such as carboxyalkylcelluloses, in particular carboxymethylcellulose, or derivatives of alginic acid.  
  These emulsions may be sensitized to certain parts of the spectrum. Suitable spectral sensitizers are, for example, the usual monomethine or polymethine dyes such as cyanines, hemicyanines, streptocyanines, merocyanines, hemioxonoles, oxonoles, azacyanines, styryl dyes and others, including also trinuclear and multinuclear methine dyes such as rhodacyanines, neocyanines, etc.. Sensitizers of this kind have been described in the work by F.K. Hamer &#34;The Cyanine Dyes and Related Compounds (lnterscience Publishers, 1964).  
  The color photographic emulsion layers and filter layers according to the invention may be hardened in the usual manner, for example with formaldehyde or halogenated aldehydes which contain a carboxyl group. such as mucochloric acid, diketones, methanesulfonic acid esters and dialdehydes.  
  Color developers are used for producing the dye images in the photographic materials according to the invention, e.g. the usual aromatic compounds of the paraphenylenediamine series which contain at least one primary amino group. The following are examples of suitable color developers:  
 N,N-dimethyl-p-phenylenediamine,  
 N,N-diethyl-p-phenylenediaminc.  
 monomethyl-p-phenylenediamine,  
 Z-amino-S-diethylaminotoluene,  
 N-butyl-N-tu-sulfobutyl-p-phenylenediamine,  
 2-amino-5-(N-ethyl-N-B-methanesulfonamidoethylamino)-toluene,  
 N-ethyl-N-B-hydroxyethyl-p-phenylenediaminc,  
 N,N-bis-(B-hydroxyethyl)-p-phenylenediamine, and  
 2-amino-5-(N-ethyl-N-B-hydroxyethylamino)- toluene. Other suitable color developers have been described, for example, in J.Amer.Chem. Soc. 73, 3100 (1951).  
  The emulsions may also contain the usual additives such as chemical sensitizers, stabilizers, phasticizers and neutral wetting agents. Even if the use of the mordants in color photographic is mainly important the mordants may be advantageously be used in black and C0ntinued Compound F E zfi lhoa ff liw C =0 on 90 cu NH us 2 882 156 a I ca coo n 0 \NHZ a o Q 9=- CH5 DT-OS 2 009 098 a: Bra en-omen] n The following results are obtained:  
 ca so fa triazine as hardener and 400 mg of saccharose mono- Solution Com- Immediately After 4 hours pound 40 laurate as nonionlc wetting agent (both in aqueous somimg m lution) are added to each of the other solutions and the I I vcuuwdispcrsion Stable solutions are adjusted to pH=6.5 and applied by im- 2 2 stable mersion casting to a cellulose triacetate support to mm? form a yellow filter layer 1.5-2 1. in thickness with a 5 g g 45 color density of 0.8 (measured behind a blue filter). 2 m The following results are obtained from testing the sta e I I u 8 l 2 orange discoloration slight flocculation u 3 3: yellow dlgpersmn Layer Com- Surface Density I pound :l ggg g 5() Before washing After washing 1 2 ll a 32 1 1 clear 08 I 0.79 Ii H f Z 2 clear 0.79 0.80 I: j z 3 3 cloudy 0.82 0.8] I7 *41 discoloration 4 C |em Ix *4: stable 3 8 clear 0.77 0.77 W Stable 5 6 9 clear 0.75 0.74 *5 2 discoloration 7 &#39;2 clear A precipitated a lmatt 0.85 0.86 8 mo&#34; rm 8 9 20 clear 0.80 0.80 fi i 10 2| clear 0.80 0.75 *1 c precipitated l 1 2s slightly 0.68 0.70 I cloudy D I2 26 clear 0.79 0.80 K E 1 I3 clear 0.80 0.76 3;&#34;&#34;5 :Sgf: I4 34 clear 0.83 0.81  
  5U l L &#34;(1 F precipitated *2: clear 2 0&#39;75 1; clear 0.8- 0.80 (1 P -WW l7 *4] matt 0.83 0.80 H vrwplwled I8 *42 mutt 0.83 0.80 19 cloudy 0.70 0.70 2U *52 matt 0.73 0.75 22 B 0.39 0.50 Solutions 2|. 23 and 26 to 28 which contain mor- 34 D uneven. M6 F. G a H alread known in the art are dams A C nd 25 E 0.57 0.56  
 eliminated from further tests.  
 white photographic materials too, for instance, anionic organic compounds such as antihalation compounds or colorless or colored DlR couplers are included in the materials to improve the sharpness and the graininess of the silver image. The following examples will illustrate the invention:  
 EXAMPLE 1 Compoui l ers cannot be obtained with known cationic mordants of the art under the same conditions.  
  It is also shown that cationic polyurethanes which do not conform to the invention are generally less suitable for preparing dye filter layers under the given conditions.  
  80 ml of an aqueous or aqueous alcoholic solution of mordant (compounds l,2.3.4.8,9,l0.l2*.20.2l,25,26,30.34,38, 39*,4l*.42*.45*,52* and comparison compounds A, B, C. D. E. F. G, H and l) are added in each case to 500 ml ofa 2 7: gelatine solution. The structure of the compounds used for comparison are shown in the following Table. The solutions of mordants are adjusted to a concentration of 0.4 equivalents of cationic groups per 1.000 ml. The solutions obtained are clear or milky.  
  75 ml ofa 4 7: solution of Dye l are introduced dropwise with vigorous stirring into the gelatine solutions which contains mordant.  
 FR 2 O03 O03 FR2OO 00 ]5o% 3 3 ca sop W3 Ca -g- 2 CH -I I-CH CH3SOLQ O-CH CH N-CH CH}- The results show that layers 8, l7, 18, 19 and 20 which do not contain cationic polyurethanes according to the invention (compounds *12, *41, *42, *45, *52) are in practice not suitable as filter layers because of the heavy cloudiness. v  
  Usable filter layers cannot be prepared with the mordants B, D and E known in the art by the method indicated.  
  Among the cationic polyurethanes which are not according to the invention. compound *39 is found to be useful.  
  All the layers are completely decolorized by treatment with alkaline baths (10 minutes at 25C in a black-and-white or color developer as indicated in Example 4 followed by minutes irrigation at 20C and drying). Dye 1 therefore remains fixed under the usual conditions and is easily washed out by the photographic process.  
 EXAMPLE 2 Example 2 shows that comparable results are also obtained when using the acid magenta dye l3 and that the cationic polyurethanes according to the invention fix the dye with a higher resistance to digestion and give rise to clear colored layers. It is shown that the mordants known in the art cause such severe flocculation of the dye that clear colored layers cannot be obtained by the simple process indicated.  
  Eighty ml of an aqueous (or aqueous alcoholic) solution or mordant are added in each case to 500 ml of a 2 gelatine solution at 40C (compounds 2. 9. 10. 12*, 20, 21. 41 42* and comparision compounds A, B, C and D).  
  Forty ml ofa 1 7: solution of Dye 13 are added dropwise with vigorous stirring at 40C to the solution which contains mordant. The following results are obtained:  
  The solutions which contain compounds 12*. A and B as mordants are not further tested. 100 mg of 13.5- trisacryloyl-hexahydro-l .3.5-triazinc and 400 mg of saccharose monolaurate are added in each case to the other solutions as in Example 1 and the solutions are adjusted to pH 6.5 and applied by immersion casting to produce layers 2 p. in thickness. The following results are obtained from testing the dry layers:  
 Layer Compound Appearance 1 2 clear 2 9 clear 3 clear 5 clear 6 21 slightly cloudy 7 41 cloudy 8 42* matt(dye precipitated) l I C mattldye precipitated) 12 D matt(dye precipitated) The dye is not washed out of the dried layers by washing (10 minutes at 20C). In the case of layers 8,  
  26 11, and 12. the dye is not completely dissolved out when the layers are treated with alkaline baths (blackand-white or color developers, see Example 4) for 10 minutes.  
 EXAMPLE 3 Example 2 is repeated except that instead of dye 13. 40 ml ofa 1 7: solution ofthe cyan dye 12 are used. The results correspond to those obtained in Example 2. 10  
 Solution Compound Appearance of fresh solution:  
  1 2 cloudy suspension 2 9 cloudy suspensnion l5 3 1(1 cloudy suspension 4 12* dye precipitated 5 20 cloudy suspension 6 21 cloudy suspension 7 41 dye precipitated X 42* dye precipitated 9 A dye precipitated 2O 10 B dye precipitated l l C dye precipitated 12 D dye precipitated Layer Compound Appearance 1 2 clear 2 9 clear a 3 10 clear 4 l2* matt. dye precipitated 5 20 slightly cloudy 6 21 slightly cloudy 7 41 mutt. dye precipitated 8 42* matt. dye precipitated 9 A unevenly cast 10 B unevenly cast l l C unevenly cast 12 D unevenly cast EXAMPLE 4 This example shows that when cationic polyurethanes according to the invention are incorporated in a multilayered color reversal film they give rise to yellow filter layers according to Example 1 which have photographically superior properties to those of a yellow filter layer prepared from colloidal silver (filter yellow) or a yellow filter layer which in addition to an acid yellow dye contains a mordant known in the art or a cationic polyurethane with a composition other than that specified in the invention.  
 45 The improvement in photographic properties is quite clear from the maximum densities obtained and the sensitivity of the individual layers under different storage conditions.  
 A color reversal film is prepared by applying the following layers successively to a layer support of cellulose triacetate which has been covered with an adhesive layer:  
 1. A red sensitized silver halide emulsion containing. per kg, 70 g of gelatine, 32 g of silver (96 7: thereof in the form of bromide and 4 7c in the form of iodide), 6 g of cyan coupler No. 5 and 24 g of cyan coupler No. 4; silver application 0.9 g/m 2. A 2 7: aqueous solution containing. per kg, 3 g of a polymeric white coupler which contains recurrent units of the following formula:  
 O CH  
 mula: 5  
 Silver application 0.8 g/m&#39;-.  
 4. A yellow filter layer Experiment 1: 1000 ml of silver yellow filter solution prepared from 1.8 g of AgNO- and 12 g of gelatine cast to provide a color density of 0.6 (measured behind a blue filter); thickness of layer approx. 1.5 1.;  
 Experiments 2-19: 500 ml of 2 7c gelatine solution to which are added 80 ml of a solution of mordant as described in Example 1 which contains 0.4 equivalents of cationic groups per 1000 ml (Compounds 2,4,9,10*,1 1,12*,20.21.30,34.38.*39. *41,*45.*52. B.D,E) and 75 ml ofa 4 7( solution of yellow dye No. 1, cast to provide a color density of 08 (measured behind a blue filter); thickness of layer 1.4-2  
 5. A nonsensitized coarse-grained silver halide emulsion containing 110 g of gelatine, 70 g of silver (98 7: in the form of bromide and 2 7: in the form of iodide) and 45 g of yellow coupler No.13 per kg;  
 silver application 1.3 g/m A total of 19 lengths of film is obtained. A sample from each length was exposed behind a continuous step wedge after several days storage under normal conditions and then developed by a reversal process as described below.  
  A second sample from each length was stored in-a moist atmosphere for 3 days (at 30C and 80 71 relative humidity) and then exposed and processed in the same manner. Processing: at 20C Black-and-white developer: (7 minutes) made up to 1000 ml with water; pH =10 Short stop bath: (5 minutes) 300 ml of distilled water 30 g of crystallized sodium acetate 5 ml of acetic acid made up to 1000 ml with water; pH 5 Rinsing: 10 minutes Reversal exposure: 2 minutes Colour development: (18 minutes) 300 ml of distilled water 2 g of nitrilotriacetic acid 3.5 g of N.N-diethyl-p-phcnylenediamine 20 g of trisodium phosphate 0.7 g of potassium bromide 0.8 g of hydroxylamine made up to 1000 ml with water and adjusted to pH 5.2  
 &#39; with acetic acid.  
 Rinsing: 5 minutes -Fixing bath: 5 minutes 150 g of ammonium thiosulfate 10 g of anhydrous sodium sulfite 2 g of hexametaphosphate made up with water to 1000 ml; pH 7 Final washing: 5 minutes.  
  The following results are obtained from the photographic assessment:  
 Experiment Yellow Response to normal stora c: Response to storage in moist at No. filter Changes compared with xperiment 1 mospherezChanges compared with normal storage layer Changes in Changes in maximum Sensitivity changes Changes in maximum sensitivity in &#34;/1 density in absolute in /1 density (absolute units units) Yellow purple cyan yellow purple cyan yellow purple cyan yellow purple cvan 1 silver 18.5 19.0 17.5&#34; 2.92 3.0 3.03 1 3 33 23 0.1 +0.06 0.25  
  filter yellow 2 compound +1 0 +0.1 0 +6 30 l 7 0. l +0.05 0. 3  
  Dye l 3 4 +16 +3 +0.15 +0.04 -l3 33 23 0.l2 +0.08 0.3 4 9 +10 3 +0.05 0 l 7 36 0. l 3 0.05 0.2 5 l0 +13 0 +0.07 0 0 27 20 0.l +0.08 0.2 6 ll 0 0 +0.51 -0.05 +13 33 23 0.48 0.-4 0.3 7 *12 76 6 +0.l 0.02 l 3 -l 3 0.3 +0.08 0.3 8 20 0 +7 0 +0.1 ().03 l 3 30 20 0.2 0.05 0.03 J 21 10 +3 +0.18 +0.02 17 23 20 0.] +0.07 0.2 H) 30 -l 7 0 0.2 0 l() 30 23 0. 12 +0.1 0.3 l 1 34 3 7 +0.25 0 +3 30 -1 3 0.2 0. 1 5 0.3 12 38 13 7 0 0 16 33 -10 0.45 +0.06 0.3 13 *3) 0 0.1 0.1 13 -47 3 0.24 0.2 0.3 14 *41 +13 0 0.2 0.04 13 27 10 0.2 +0.24 0.27 15 *45 +20 0 0.05 0.05 0 40 1 7 0.2 +0.1 0.27 16 *52 +73 6 0.46 0.1 37 64 13 +0.4 +0.3 0.23 17 B +30 0.4 0.03 10 1 10 -20 +0.25 +0.4 0.] 18 D +100 +77 0.38 0.2 30 90 20 +0.30 +0.15 0. 1 19 E +63 0.50 0.19 0 66 30 0.] 0.1  
 The values entered with a were not measured &#34;sensitivity given in DIN The results show that both the mordants B. D and E known in the art and the cationic polyurethanes *l l, 12, *39, *41, *45 and *52 which are not in accordance with the invention are markedly inferior to the cationic polyurethanes 2,4,9,l0,20,2l,30 and 34 according to the invention on account of their undesired photographic side effects. The cationic polyurethanes ac cording to the invention are superior because they do not exhibit accelerating effect on development (for increase in sensitivity in the green sensitive layer and in the red sensitive layer, see experiments l7, l8 and 19; reduction in maximum density due to pronounced negative fog especially in the green sensitive layers in experiments l2,l4,l5,l6,l7,l8 and 19 [Compounds 39. 41, 45, 52, B, D and E1). Secondly, the behaviour of the cationic polyurethanes according to the invention under conditions of storage in a moist atmosphere invariably deviates less from the results obtained in Experiment 1 than the behaviour ll,l2,39,41,52, B, D and E.  
  The improvement in properties of the cationic polyurethanes according to the invention as mordants for filter dye 1 compared with those of silver yellow filter layers is clear from the increase in green sensitivity (more advantageous position of the absorption flank of dye 1 compared with that of filter silver yellow) combined with the increase in maximum density in magenta (absence of contact fog in the green sensitive emulsion. hence higher color yield in magenta at the given ratio of AgX to color coupler).  
  It is particularly clear from the results that when silver yellow filter is replaced by a yellow filter layer which contains a cationic polyurethane according .to the invention in combination with a filter dye, neither the ratio of sensitivity to maximum density nor the storage stability of the material is deleteriously affected.  
  Furthermore, the film samples obtained from experiments 7,14,15 and 16 (compounds 12, 41, 45 and 52) have an undesirable cloudiness or surface matting, which was to be expected from the results of Example 1. The samples of film obtained from experiments l7, l8 and I9 (compounds B, D and E) show severe irregularites in casting.  
 What is claimed is:  
  l. A light-sensitive photographic material containing at least one silver halide emulsion layer and having at least one colloidal layer, which contains in said emulsion or in said layer at least one anionic organic compound and a basic mordant for said anionic organic compound comprising a polymer of a water soluble or of compounds water dispersable cationic polyurethane wherein the improvement comprises the cationic polyurethane is a polymer having at least two recurring units prepared from a. an alkancdiol component of which at least mols 7r by weight is one or more amino containing diols of the formula ao- CH2-CH2-N-CH2-CH2-OH and up to 20 mols by weight is one or more diols of the formula HOR;,OH alternating with b. a diisocyanate component selected from the group consisting of aliphatic. cycloaliphatic and aromatic diisocyanates, said diisocyanate component containing at least 40 mols by weight aliphatic or aliphatic and cycloaliphtic diisocyanate and not more than 20 mols 7: by weight of cycloaliphatic diisocyanate; wherein at least 40% by weight of all the tertiary amino groups in the polyurethane are quaternized, and wherein R is an alkyl group containing 2 to 10 carbon atoms, R; is an aliphatic hydrocarbon chain which may be interrupted by one or more -O, S  
  and/or NCH;, groups; said polyurethane having an average molecular weight of 10,000 to 60,000.  
  2. The material as claimed in claim 1 in which 70 to mols 7( by weight of component (b) is hexamethylene diisocyanate.  
  3. The material as claimed in claim 1 in which 70 to by weight of the tertiary amino groups in the polyurethane are quaternized.  
  4. The material as claimed in claim 1 in which the polyurethane is present in a silver halide emulsion layer.  
  5. The material as claimed in claim 4 in which the anionic compound is a color coupler.  
 6. The material as claimed in claim 1 in which the anionic compound is a dyestuff.  
  7. The material as claimed in claim 6 in which the dyestuff is a diffusible filter dye in the absence of said basic mordant.