Patent GB-407066-A (GB)
Title: Improvements in dyeing animal fibres
IPC: D06P1/32
Filed: 1932-09-01
Abstract: Animal fibres such as skins, hair, fur and leather are dyed by treating them with a solution of a compound of the general structure <FORM:0407066/IV/1> wherein R is an alkyl radicle, X1 and X2 are hydrogen atoms or members of a benzene ring and Y is hydrogen or the same radicle <FORM:0407066/IV/2> or mixtures of such compounds, in the presence of an oxidizing agent, blue and green dyeings are obtained.  Suitable compounds include 1.4-naphthohydroquinone-monoalkylethers, 1-hydroxy-4-alkoxyanthracenes, 1-1<1>-dihydroxy-4-4<1>-dialkoxy-2-2<1>-dinaphthyls or dianthranyls. Other readily oxidizable aromatic compounds containing amino or hydroxyl groups such as p-diaminobenzene, p-aminophenol, o-aminophenol or a -naphthol may be added to the solutions.  The fibrous materials may be mordanted with iron, copper, chromium or other metal compounds.  The solution may be neutral, acid or alkaline and the oxidizing agent may act on the compound for some time before the fibres are introduced.  Suitable oxidizing agents include hydrogen peroxide, peroxides such as sodium or barium peroxide, nitrites, chromates, persulphates and perborates.  Emulsifying agents such as oleyl sulphonate, sulphite waste liquor and alkylated naphthalene sulphonic acids may be added to the dyebath.  In examples: (1) skins mordanted with potassium bichromate are introduced into a solution of 1-4-naphthohydroquinone monomethyl ether in aqueous caustic soda with or without the addition of alkylated naphthalene sulphonic acid or sulphite cellulose waste liquid to which has been added hydrogen peroxide, reddish blue shades being obtained.  Copper or iron mordants yield greenish blue shades; (2) skins or leather are introduced into a solution of 1-4-naphthohydroquinone monomethyl ether or the corresponding ethyl or amyl compounds in aqueous caustic soda to which has been added hydrogen peroxide, the skin being dyed blue and the hair black in the presence of a chromium mordant; (3) chrome mordanted skins are introduced into a solution of 1.4-naphthohydroquinone monomethyl ether in aqueous caustic soda to which has been added hydrogen peroxide and the skins, which have been dyed dark-blue shades are introduced, after, if desired rinsing and/or treating with a metal mordant, into a solution of p-p-diaminobenzene in water and hydrogen peroxide. Black shades are obtained; (4) mordanted skins are introduced into a solution of 1-hydroxy-4-methoxy or -ethoxy-anthracene or derivatives thereof in aqueous caustic soda containing hydrogen peroxide or other oxidizing agents such as nitrites, peroxides, chromates, persulphates or perborates to yield olive green shades. r-Diaminobenzene, p- or o-aminophenol or a -naphthol and metallic mordants such as iron, copper or chromium compounds may also be present; (5) mordanted skins are introduced into a solution of 1 - 1<1> - dihydroxy - 4 - 4<1>-dimethoxy-2<1>-2-dinaphthyl or-dianthranyl in aqueous caustic soda containing hydrogen peroxide to obtain blue or olive green shades.  Specification 23193/04, [Class 15], is referred to. 1-Hydroxy-4-alkoxyanthracenes are obtained by partial alkylation of the 1-4-dihydroxy compounds under mild conditions such as by stirring with the alcohol and hydrochloric acid in the cold. 1-1<1>-Dihydroxy-4-4<1>-dialkoxy-2-2<1>-dinaphthyls or dianthranyls are obtained by mild oxidation of the 1-hydroxy-4-alkoxy-naphthalenes or -anthracenes with, for example, air in the presence or absence of alkali.