Improvements in dyeing

摘要

534,903. Dyeing textiles. ELLIS. G. H., and WESSON, A. J. Sept. 20, 1939, No. 26252. [Class 15 (ii)] Surface-saponified cellulose ester textile materials, e.g., such as are obtainable by the processes of Specifications 304,596 or 309,377, [both in Class 15 (ii)], are coloured in dark shades by applying thereto or forming thereon one or more dyestuffs for the cellulose ester core and one or more dyestuffs for the cellulose sheath, the latter dyestuff or dyestuffs imparting a grey or other neutral shade in the absence of the former dyestuff or dyestuffs. Dischargeable dark shades are obtainable by the use of a dischargeable direct cotton dyestuff for the sheath and a dischargeable cellulose acetate dyestuff for the core. The sheath and the core may be dyed from a single bath or from separate baths and the saponifying agent may be incorporated in the dyebath. In examples, (1) a fabric made of surface-saponified cellulose acetate yarns is dyed from a soap or sulphated fatty alcohol bath at 75-80‹ C. containing a direct cotton colour, e.g., chlorazol fast black BKS or Benzo fast grey BM capable of yielding a grey or blackish shade on the cellulose sheath, and a dispersed cellulose acetate dyestuff, e.g., 4 41-diamino-3 : 31-dinitrodiphenylmethane, 4-nitro-21: 51:dimethyl- 41 - aminoazobenzene or 1 - methylamino - 4 - #-hydroxyethylaminoanthraquinone, capable of yielding a pale or medium primary or. secondary shade, e.g., yellow, orange, red, blue or green, on the cellulose acetate core, common salt being added toward the end of the dyeing operation to assist the exhaustion of the direct cotton colour; a table is given showing the dark shades obtainable with various combinations of dyestuffs ; alternatively, the cellulose acetate and direct cotton dyestuffs may be applied separately in either order, the former from a soap bath and the latter from a salt bath ; (2) a similar fabric is similarly dyed a full maroon by treatment in a soap bath containing Diazo fast green GFL for the sheath. and aminoazobenzene for the core, followed by diazotization on the fibre and development with #-naphthol. The use of vat and sulphur dyestuffs also is specified.