Patent GB-598476-A (GB)
Title: Improvements in colour-formers and processes of colour photography
IPC: G03C7/327
Filed: 1945-03-23
Abstract: A polymeric dye intermediate, suitable for use in colour photography, which is a hydrophilic ether of a partial cellulose derivative, is obtained by reacting a cellulose derivative of high degree of polymerization which is soluble in water and in water-ethanol mixtures and which contains 0.5 to 1.5 substituent groups per C6 cellulose unit, with a dye intermediate containing a reactive hydroxyl or halide group attached to a non-aromatic hydrocarbon group, the proportions of the reactants being such that the product contains 0.3 to 1 dye intermediate groups per C6 cellulose unit.  As a modification, the water-soluble cellulose derivative may be reacted with a bifunctional connecting compound such as an aldehyde and with a dye-intermediate containing an aldehyde-reactive group.  As another modification, a partial nitrobenzyl ether of cellulose may be reduced and the water-soluble product may be reacted with a dye intermediate which is an acid chloride.  As a further modification, the water-soluble cellulose derivative may be a partial glycollic acid ether and it may be reacted with a dye intermediate containing an amino group.  In all cases the compounds formed are cellulose ethers containing ether groups attached through an alkane hydrocarbon group to a dye intermediate group.  They may be mixed with light-sensitive silver salts to form light-sensitive hydrophilic colour-yielding compositions. These compositions may be coated from solution on to a support in thin layers.  The silver halide may be formed in situ in the cellulose derivative solution.  The cellulose derivative may be a methyl, ethyl, hydroxyethyl, or carboxymethyl ether, or an acetate, propionate, acid phthalate, succinate, or hydroxyacetate. The dye intermediate group may be derived from a b -ketoacylamide (e.g. benzoyl-, p-nitrobenzoyl-, p-nitro-, aceto-, naphthoyl-, or furoyl-acetanilide or p-acetoacetamino-benzoic acid), a pyrazolone (e.g. 1 - phenyl - 3 - methyl - 5 - pyrazolone, or 1 - m - sulphophenyl-3-methyl-5-pyrazolone), indoxyl or thioindoxyl, a N-homo-phthalylamine, e.g. N - homophthalyl - aniline, 2 : 4 - dihydroxy - quinoline, p-nitrobenzyl cyanide, diketo hydrindene, a malonamide (e.g. ethyl N-phenyl malonamide or N : N1-diphenyl malonamide), phenacyl pyridinium bromide, hydroxypyridine, cyanacetanilide or ethyl cyanacetate.  The dye intermediate group may be any phenol, naphthol, or aromatic amine having a coupling position available ortho or para to the aromatic hydroxyl or amine group, or having any active methylene group. The change in water-solubility produced by introduction of the dye-intermediate groups may be balanced by the selection of cellulose derivatives and dye intermediates of appropriate water-solubility.  The cellulosic material may be stirred with caustic soda solution, and a dye intermediate containing an aliphatic chloride, bromide or iodide group, e.g. a halo methyl group is added and the mixture warmed to split off hydrogen halide, thus connecting the colour-forming nuclei to the polymer chain through an ether linkage.  A partial glycollic acid ether may be formed by reacting the hydrophilic polymer with chloracetic acid and sodium hydroxide, and then the carboxylic groups are converted to amides by reaction with dye intermediates containing amino groups.  Nitrobenzyl ethers of the cellulose derivative may be reduced to amino compounds and then reacted with dye intermediates which are acid chlorides.  When using aldehyde as linking material, the aldehyde may be added to a solution or dispersion of the cellulose derivative and dye intermediate in the presence of a catalyst, or a methylol compound of the dye intermediate may be formed first and then condensed with the cellulose derivative, or the methylol compound of the cellulose derivative may be condensed with the dye intermediate.  In an example, methyl cellulose is condensed with o-hydroxy benzyl alcohol, in presence of dioxane and phosphoric acid.  The polymeric dye intermediate is dissolved in aqueous ethyl alcohol and used in making an emulsion for colour photography (see Group XX).  In other examples, sodium cellulose glycolate is reacted with 2-phenyl-4-chlorphenol and formaldehyde in presence of caustic soda to form a mixed glycolic acid ether/2-hydroxy-3-phenyl-5-chlorbenzyl ether of cellulose; methyl cellulose is reacted with a methylol compound of 2-phenyl-4-chlorphenol to form a mixed methyl ether/2-chloro-3-phenyl-5-chlorobenzyl ether of cellulose; methyl cellulose is reacted with 1-phenyl-3-methyl-5-pyrazolone in presence of glacial acetic acid and the product is reacted with paraformaldehyde.  In another example, methyl cellulose, paraformaldehyde, glacial acetic acid and phosphoric acid are heated together and then o-chloroacetoacetanilide is added to form a mixed ether of cellulose.  In another example, sodium N-phenylacetoacetanilide in dioxane is mixed with methyl chloromethyl ether.  The product is reacted with hydroxyethyl cellulose to form a mixed ether of cellulose.  In another example, cellulose acetate is reacted with a condensation product of paraformaldehyde and 1 - N - b - hydroxyethylamino - naphthalene - 6 - sulphonic acid.  In another example, methyl cellulose is reacted with p-nitrobenzyl chloride. The nitro group in the product is then reduced with hydrogen using a platinum oxide catalyst.  The product is acetylated with diketene to give a p-acetoacetamino benzyl ether of cellulose.  The cellulose dye intermediate compounds may be coupled with the oxidation products of colour coupling aromatic primary amino developing agents, formed on development of silver salt images to form quinoneimine (including indamine, indoaniline and indophenol) or azomethine dye images.  They may also be coupled with diazotized aromatic amines p  to form azo dye images.  Specifications 545,443, 545,444, [both in Group XX], and 569,646 are referred to.