GB669028A - Improvements in coloured fluorescent artificial textile materials - Google Patents

Abstract

Artificial filaments exhibit substantially the same colour when viewed in white light as when viewed in ultra-violet light, due to the presence therein, distributed throughout the material of the filaments, of a finely-divided fluorescent inorganic pigment and an organic non-fluorescent dye of good resistance to ultra-violet light, the dye imparting to the filaments a colour in white light which is substantially the same as that imparted by the fluorescent pigment in ultra-violet light. Fluorescent pigments used are zinc sulphide, cadmium sulphide, cadmium tungstate, mercuric oxide, magnesium dichromate, barium chromate, thorium dichromate and rhodium thiocyanate. Several non-fluorescent dyes are referred to. The artificial filaments can have a basis of cellulose acetate or other organic derivative of cellulose or of regenerated cellulose. The filaments containing the fluorescent pigment can be produced by extruding into a setting medium a spinning solution containing the finely divided pigment. Filaments having a basis of cellulose acetate or other organic derivative of cellulose can be dyed with a water-insoluble dye having direct affinity for the filaments when applied thereto as an aqueous dispersion. Filaments having a basis of regenerated cellulose can be dyed by means of a direct cotton dye. According to one process the filaments containing the fluorescent pigment are produced by extruding and setting into filaments a cellulose ester solution containing a finely-divided fluorescent pigment, stretching the filaments to a substantial degree and thereafter saponifying them substantially completely.ALSO:Artificial filaments exhibt substantially the same colour when viewed in white light as when viewed in ultra-violet light, due to the presence therein, distributed throughout the material of the filaments, of a finely divided fluorescent inorganic pigment and an organic non-fluorescent dye of good resistance to ultra-violet light, the latter imparting to the filaments a colour in white light which is substantially the same as that imparted by the fluorescent pigment in ultra-violet light. Fluorescent pigments used are zinc sulphide, cadmium sulphide, cadmium tungstate, mercuric oxide, magnesium dichromate, barium chromate, thorium dichromate, and rhodium thiocyanate. Several non-fluorescent dyes are referred to. The artificial filaments can have a basis of cellulose acetate or other organic derivative of cellulose or of regenerated cellulose. The filaments containing the fluorescent pigment can be produced by extruding into a setting medium a spinning solution containing the finely divided pigment. Filaments having a basis of cellulose acetate or other organic derivative of cellulose can be dyed with a water-insoluble dye having direct affinity for the filaments when applied thereto as an aqueous dispersion. Filaments having a basis of regenerated cellulose can be dyed by means of a direct cotton dye. In one example a mixture of 1 part by weight of zinc sulphide and 400 parts by weight of a 25 per cent solution of cellulose acetate in acetone is extruded through a spinning jet into warm air where the volatile solvent is removed. The yarn obtained is then dyed in hank form with a 30 : 1 aqueous dye bath comprising 0.5 per cent of 4-nitro-21 - methyl - 41 - dihydroxyethyl - amino - azobenzene (based on the weight of the yarn) dispersed with the aid of sulphonated ricinoleic acid. Dyeing is effected at a temperature of 180 DEG F. The yarn has a bright red colour. The yarn may also be dyed by padding the hank with a solution of 0.5 parts by weight of Fast Red A (C.I. No. 176) in 30 parts by weight of a 25 per cent aqueous solution of ethyl alcohol containing 2 per cent of sodium thiocyanate at 68 DEG F. In another example a mixture of 1 part by weight of a mixture of zinc sulphide and cadmium sulphide and 400 parts by weight of a 25 per cent solution of cellulose acetate in acetone is extruded as in the first example. The yarns obtained are then dyed in hank form in an aqueous dye bath containing 0.5 per cent (based on the weight of the yarn) of the azo dyestuff formed by coupling diazotized p-amino-acetanilide with p-cresol, the dye bath being maintained at 180 DEG F. The yarn has a bright yellow colour. The yarn may also be dyed by a liquid containing 0.5 parts by weight of Artol Yellow SG dissolved in 30 parts by weight of a 25 per cent aqueous solution of ethyl alcohol containing 2 per cent of sodium thiocyanate. The dyeing is effected by padding with the dye liquid at 68 DEG F.