GB996068A - Fugitive dyestuffs - Google Patents

Abstract

The invention comprises fugitive dyestuffs of the formula <FORM:0996068/C3/1> where R is a dyestuff radical, n is at least 15, x is 1 to 6 and the product of n and x is at least 30. Preferably x is 1 or 2 and when x is 1, n is 50 to 200, and when x is 2, n is 25 to 100. The radical R may be derived not only from true dyestuffs but also from compounds which merely contain a chromophoric group, e.g. nitroanilines and chlorodinitrobenzene. R is preferably an azo dye radical linked to the ethelenoxy groups by at least one nitrogen atom. These compounds may be prepared by reacting ethylene oxide or polyethylene glycol with a primary or secondary aromatic amine and coupling the product with an aromatic amine diazonium salt. Other radicals represented by R include nitroso, nitro, diphenylmethane, triarylmethane, xanthene, acridene, methine, thiazole, indamine, azine, oxazine and anthraquinone. The dyestuff preferably contains a sulphonic acid radical, e.g. in the form of a salt. Other methods of preparing the compounds comprise: (1) anthraquinones having Cl, Br or I attached to the nucleus may be reacted with excess polyethylene glycol monoamine; (2) an anthraquinone carboxylic acid may be reacted with polyethylene glycol; (3) an aromatic bromine compound, e.g. 2-bromo-anthraquinone, may be reacted with polyethylene glycol in the presence of sodium; (4) a nitrophenol may be reacted with polyethylene glycol and then reduced to the amino compound which can be diazotized and coupled; (5) a compound of the formula R11N(R1)(CH2CH2O)nH, where R1\h is alkyl or aryl or (CH2CH2O)nH and R11 is aromatic with chloro, nitro, methoxy or other substituents but having at least one unsubstituted reactive position, may be reacted with sodium nitrite and an acid to produce a nitroso tint; this can also be reduced to a primary amino group and coupled as above to obtain azo dyes. Examples are given of the preparation of polyethenoxy derivatives of aniline, naphthylamine and their derivatives and their subsequent conversion to dyes.ALSO:Fugitive dyestuffs used for identification of fibres comprise compounds of the formula R[(CH2CH2O)nH]x where R is a dyestuff radical, n is at least 15, x is 1 to 6 and the product of n and x is at least 30. The radical R is preferably an azo or anthraquinone dye radical but may also be nitroso, nitro, diphenylmethane, triarylmethane, xanthene, acridene, methine, thiazole, indamine, azine and oxazine. Suitable fibres are cotton, wool, viscose, cellulose esters, nylon, polyacrylonitriles and polyesters and paper. They may be treated by spraying with an aqueous solution of the dye, drying and optionally baking and steaming, or by boiling in the dye solution and drying. The tint is removed by washing with water or aqueous soap or detergent. The dyes may be temporarily insolubilised by reaction with water soluble polyacrylic acid. Thus the dyed fibres may be mixed with others and passed into an aqueous solution of polyacrylic acid, e.g. in a slashing operation, and no bleeding on to the untinted fibres occurs. The dyes may be resolubilised with a ketonic solvent or a mild detergent scour.