Patent GB-413713-A (GB)
Title: Improvements in processes of printing or dyeing animal fibres
IPC: D06P1/28
Filed: 1932-11-14
Abstract: Animal fibres are dyed or printed with vat-dyes by applying to the fibre an ester salt of a leuco vat-dye and an ammonium salt or an alkyl ester of a non-volatile organic acid as a compound capable of splitting off acid when steamed but free from any tendency to cause dissociation of the ester salt, and either (a) the fibre is steamed to fix the ester-salt thereon in the unchanged leuco form and development then obtained by treatment in a mineral acid bath containing a chlorate or bromate, or (b) lead chromate being also added to the printing paste, the fibre is then steamed to fix the ester-salt thereon in the unchanged leuco form and development effected in a mineral acid bath.  The specified substances which split off acid when steamed but do not cause dissociation of the ester salts are ammonium thiocyanate, diethyltartrate, ammonium oxalate and ammonium tartrate.  In Examples: (1) the leuco sulphuric ester of 1-oxy-4-chlornaphthalene-4<1>-methyl-5<1>-chloro-7<1> -methoxyindol-2-indigo is made into a paste with glycerine, thiodiglycol, tragacanth mucilage, ammonium thiocyanate and water and printed on muslin-de-laine, dried, steamed and developed at 75--95 DEG  C. in a bath containing sulphuric acid, sodium chlorate and ammonium vanadate; (2) wool or silk is printed with a paste comprising an ester salt of a leuco vat dye, sodium benzylaniline sulphonate, glycerine, ethyleneglycol - monoethylether, tragacanth, gum mucilage, ammonium thiocyanate and lead chromate, dried, steamed and developed in a dilute hydrochloric acid bath at 85 DEG  C. Specifications 186,057, 203,681, 281,336, 298,648, and 313,407, [all in Class 15 (ii)], are referred to.  The Specification as open to inspection under Sect. 91 comprises a process wherein an ester salt of a leuco compound of a vat-dye is applied to the fibre, fixed thereon unchanged by steaming, and then developed by passing through a mineral acid bath; the presence during the steaming operation of a compound capable of splitting off acid when steamed but free from any tendency to cause dissociation of the ester salt is a modification of this process.  In further Examples: (3) muslin-de-laine or silk is printed with the ester salt of the leuco compound of 5.6.7<1>-trichloro-(2)-oxythionaphthene - 5<1> . 7<1> - dichloro - 2<1> - indolindigo in a paste with glycerine, ammonium vanadate, British gum and ammonium thiocyanate, dried, steamed and developed in a bath of dilute sulphuric acid and sodium chlorate; the above ester salt may be replaced by that of the leuco compound of 5.7.5<1>.7<1>-tetrabromoindigo or 4 . 4<1> - dimethyl - 6 . 6<1> - dichlorthioindigo; (4) muslin-de-laine is padded with the sulphuric ester salt of leucodibenzpyrenequinone in a paste with glycerine, thiodiglycol, diethyltartrate, ammonium vanadate and tragacanth mucilage, dried, steamed and developed as in (3) : (5) bleached wool or silk is printed with a paste of the sulphuric ester salt of the leuco compound of 4 . 4<1> - dimethyl - 6 . 6<1> - dichlorthioindigo, glycerine, ethyleneglycol monoethylether, ammonium thiocyanate, sodium acetate, tragacanth, British gum, and lead chromate, dried, steamed and developed in a bath of dilute hydrochloric and oxalic acids; instead of the above ester salt there may be-used that of the leuco compound of 5.7 : 5<1>.7<1>-tetrabromindigo, 5 . 6 . 7 - trichloro - (2) oxythionaphthene - 5<1> - 7<1> - dichloro - (2<1>) - indolindigo and 4 - chlornaphthalene - 2 : 4<1> - methyl-5<1> - chloro - 7 - methoxyindol - 2 - indigo.  This subject-matter does not appear in the Specification as accepted.