Patent GB-705171-A (GB)
Title: Colour photography
IPC: G03C7/29
Filed: 1950-12-28
Abstract: Azo dyes, useful in colour photography on account of their ability to charge colour with variations in pH, possess the general formula X-A-N=N-B-Y, wherein A and B represent aromatic radicals, X represents an electropositive group (e.g. a hydroxy, amino or alkylated or arylated amino group or an amino group acylated with an organic sulphonic acid), and Y represents a substituent, preferably an electronegative group (e.g. a nitro, sulpho, sulphone, sulphamide, carboxylic acid, ester or amide, keto, nitrile, vinyl or azo group), or wherein B and Y together represent the residue of a coupling component comprising a reactive methylene group.  When Y represents an azo group -N=N-Z, the dyes are disazo dyes (primary, secondary or derived from the tetrazotized diamines) of the general formula X-A-N= N-B-N=N-Z, wherein Z may be identical with or different from the residue X-A.  Preferred dyes are those of the following general formulae: <FORM:0705171/IV(c)/1> (wherein R1 represents hydrogen or a monovalent substituent, R11 represents hydrogen or a hydroxy, ether or acylamino group, and Y represents a nitro, sulpho, sulphone, sulphonamide, vinyl or azo group), <FORM:0705171/IV(c)/2> (wherein X represents a dialkylamino group, R represents an ether or acylamino group, and R1 represents hydrogen or a sulpho, sulphone or sulphonamide group), <FORM:0705171/IV(c)/3> (wherein X represents a dialkylamino group and BY the residue of pyrazolone), and <FORM:0705171/IV(c)/4> (wherein NR2 represents an amino group in which R is hydrogen or an organic residue).  In some cases dyes not sensitive to pH charges may be simultaneously employed.  Specific dyestuffs mentioned in the examples include: (Examples 1-3) 4-nitraniline-2-sulphonic acid --> 1-p-toluenesulphamino-5-naphthol, 2.5-dichlorosulphanilic acid --> 1-naphthol; (Example 4) sulphanilic acid --> 2.5-dimethoxyaniline --> 1-naphthol, 4-acetylamino-1-naphthylamine-6-sulphonic acid --> 1-naphthol, metanilic acid --> salicoyl-anhydroamino-benzyl-alcohol; (Example 5) 4-nitro-1-diazonaphthalene-6-sulphonic acid coupled with naphthalene-1, 5-di-(sulphonaphthionyl - 1' - 5' - aminonaphthol); (Example 6) 4.4'-diaminoazobenzene \sQ 1-naphthol, 4-amino-2, 5-dimethoxyazobenzene-4'-sulphonic acid --> 1-toluenesulphamino-5-naphthol, a polymeric dye metanilic acid --> anhydroaminobenzyl-alcohol-salol reaction product, 4.4'-diaminophenyl ether \sQ adipyl-H-acid; (Example 7) 4-nitraniline-2-sulphonic acid --> 1 (naphthalene-2-sulphamino-5-naphthol, aniline-2.5-disulphonic acid --> 1-naphthylamine --> 2-ethoxy-1-naphthylamino-6-sulphonic acid --> phenyl J acid, 4-nitraniline-2-sulphonic acid --> N-N-(di-n-butyl)-m-phenetidine, benzidine-2-2'-disulphonic acid \sQ adiphyl H acid, metanilic acid --> N, N', N"-trisalicylylmelamine; (Example 8) 4-nitraniline-2-sulphonic acid \sQ 2.6-di-(piperidinomethyl)-1.5-dihydroxynaphthalene, 4.4'-diaminostilbene-2-2'-disulphonic acid \sQ 2-decanoyl-1-naphthol, m-sulphobenzoic ester of 2-naphthylamino-6.8-disulphonic acid --> p-cresol.  Example 9 and various lists specify numerous other dyes. Specifications 395,718, 397,159, 397,188 [all in Group XX], 516,883 and 682,665 are referred to.