Patent GB-593088-A (GB)
Title: Processes of colour photography and elements therefor
IPC: G03C1/053
Filed: 1945-03-23
Abstract: Hydrophilic polyvinyl alcohol ethers, wherein the dye-intermediate nuclei are each linked to a single carbon atom in the chain of carbon atoms of the polyvinyl alcohol through a single aliphatic ether linkage may be formed by reacting a dye intermediate containing a reactive group (e.g. OH or Cl) attached to a non-aromatic hydrocarbon group with a polyvinyl alcohol, or by linking the dye intermediate groups to the polyvinyl alcohol by means of a bifunctional connecting agent (e.g. formaldehyde, acetaldehyde or benzaldehyde).  A number of ether groups may be introduced into each molecule of the polymer. The polyvinyl alcohol may be derived by complete or partial hydrolysis of a polyvinyl ester such as the acetate, chloracetate, propionate or butyrate with possible further reaction to introduce minor proportions of other modifying groups such as acetal, ester, or ether groups or by complete or partial hydrolysis of an interpolymer of a vinyl ester with minor proportions of other vinyl compounds such as vinyl chloride or alkyl acrylates or methacrylates.  The original dye intermediate may be a phenol, naphthol or aromatic amine having a coupling position o or p to the aromatic OH or NH2 group or may be a reactive methylene compound.  Numerous such intermediates are specified.  A group or atom readily eliminated (e.g. a sulphonic or carboxylic acid group or a halogen atom) may be in the coupling reactive position.  A polyvinyl alcohol containing the group (-CH2-CHOH-)n, in which n is at least 100, and a dye intermediate may be linked by condensation with formaldehyde-yielding material, either by adding formaldehyde to a solution or suspension of the two components in presence of a catalyst or by first condensing the formaldehyde with either component to form a methylol derivative and condensing this derivative with the other component.  The colour-forming nuclei need not be attached directly to the methylene ether group, since the formaldehyde may react with non-colour-forming groups (e.g. amide, mercapto, or aliphatic amino or hydroxyl) in the dye intermediate to form the methylol derivative.  The dye intermediate nuclei may be joined to the polymer chain through other ether groups such as -OCH2COX, -OCH2CH2X, -OCHRX, -OCR2X, -OCH2CH2SX, -OCH2C6H4X, -OCH2OCH2COX, -OCH2CHOHCH2OX, -OCH2CH2NHX, or -OCH2OCH2X, wherein R represents a small alkyl radical and X a dye intermediate group. The change in water-solubility and water-permeability produced by the introduction of the dye intermediate groups may be balanced by the selection of a polyvinyl alcohol of suitable viscosity and solubility, by the introduction into the polymer of groups having the appropriate solubilising or insolubilising effect (e.g. acetal groups from acetaldehyde, butyraldehyde, benzaldehyde, benzaldehyde-o-sulphonic acid, phthalaldehydic acid, or glyoxylic acid; ester groups from acetic, butyric, benzoic, phthalic or succinic; or ether groups (for example with hydroxy acids, e.g. glycollic), which groups may be introduced before or after condensation of the dye intermediate with the polymer, or by the introduction into the dye intermediate of solubilising groups such as sulphonic or carboxylic acid groups.  When used as photographic emulsion layers, the ethers may contain sensitizing dyes, hypersensitizers, antifogging agents, preservatives or hardeners, Example 1 illustrates the production of a dye-forming polymer from saligenin and polyvinyl alcohol by heating together in dioxane containing phosphoric acid.  In example 2, the reaction product of phenol and formaldehyde is further reacted with polyvinyl alcohol in dioxane containing phosphoric acid.  Further examples describe the production of dye-forming polymers from polyvinyl alcohol and (a) 2 - hydroxy - 3 - methyl - 5 - chlorobenzyl alcohol, (b) o-phenylphenol, (c) a -naphthol, formaldehyde and o-sulphobenzaldehyde, (d) 1-phenyl-3-methyl-5-pyrazolone, formaldehyde and o-sulphobenzaldehyde, (e) o-chloracetoacetanilide and formaldehyde, (f) sodium acetoacetanilide and chloro and methyl methyl ether, (g) N-phenylacetoacetanilide and paraformaldehyde, 1-N-hydroxyethylaminonaphthalene, 95 per cent hydrolysed polyvinyl acetate and paraformaldehyde may be reacted and then further reacted with phthalaldehydic acid.  Polyvinyl alcohol may be reacted with p-nitrobenzyl bromide, the nitro group reduced with hydrogen in the presence of platinum oxide catalyst, and the product reacted with diketene to give a partial p-acetoacetaminobenzyl ether of polyvinyl alcohol.  Specifications 545,443, 545,444, [both in Group XX], and 569,646 are referred to.