Patent GB-421606-A (GB)
Title: Improvements in textile printing
Filed: 1933-06-26
Abstract: Vat dyes, dyeing with; printing.--Sulphuric ester salts of leuco vat dyestuffs are applied to textiles in dyeing, printing or stencilling processes in conjunction with dibenzylsulphanilic acid or a soluble salt thereof or a solution of either in diethylene glycol or other polyhydric alcohol.  The process is of particular value with such sulphuric ester salts of low solubility, e.g. Indigosol brown IRRD, Indigosol pink IR extra, Indigosol red violet IRH and Soledon brilliant purple RR.  The following examples are specified: (1) White cotton cloth is printed with a paste containing Indigosol brown IRRD, hot water, starch tragacanth thickening and the sodium salt of dibenzylsulphanilic acid and the printed goods are dried, aged for 5 minutes, passed through a bath at 35 DEG  C. containing sodium bichromate and sulphuric acid, washed and soap-boiled.  (2) White cotton cloth is printed with a paste containing Indigosol pink IR extra, diethylene glycol, hot water, starch tragacanth thickening, sodium nitrite and the sodium salt of dibenzylsulphanilic acid and the printed goods are dried, passed through a dilute sulphuric acid bath at 70 DEG  C., washed and soap-boiled.  (3) The goods are similarly printed using the dyestuff Indigosol brilliant pink 13B, dried, aged for 5 minutes and developed as in (2).  (4) Cotton cloth is passed through a solution at 20 DEG  C. containing the potassium salt of the tetrasulphuric acid ester of 3 : 3<1>-dichlorodianthrahydroquinoneazine (cf. Specification 334,902, [Class 2 (iii)]), gum tragacanth, the sodium salt of dibenzylsulphanilic acid and sodium nitrite, squeezed, dried, treated for 3 minutes in a dilute sulphuric acid bath at 50 DEG  C., p rinsed, soap-boiled, rinsed and dried.  (5) Cotton cloth is similarly dyed, using the dyestuff Indigosol brown IRRD.  (6) Cotton cloth is worked for 45 minutes in a bath at 50 DEG  C. containing Soledon brilliant purple RR, sodium chloride and the sodium salt of dibenzylsulphanilic acid, squeezed, treated for 5 minutes in a cold bath containing sulphuric acid and sodium nitrite, rinsed, soap-boiled, rinsed and dried.  (7) Cotton cloth is worked for 30 minutes in a bath at 70 DEG  C. containing Indigosol brown IRRD, sodium sulphate, the sodium salt of dibenzylsulphanilic acid and sodium nitrite, squeezed, worked for 3 minutes in a dilute sulphuric acid bath at 50 DEG  C., rinsed, soap-boiled, rinsed and dried.  (8) A paste containing Indigosol pink IR extra, hot water, diethylene glycol, the sodium salt of dibenzylsulphanilic acid, a thickening and sodium nitrite is brush stencilled on to cotton fabric which is then dried, aged for 5 minutes, passed through a dilute sulphuric acid bath at 65 DEG  C., washed and soap-boiled.  (9) An aqueous solution containing Indigosol brown IRRD powder, diethylene glycol, the sodium salt of dibenzylsulphanilic acid and sodium nitrite is spray stencilled on to a fabric which is then dried, aged and developed as in (8).  Dibenzylsulphanilic acid is obtained by treating sulphanilic acid with an appropriate excess of benzyl chloride in caustic soda solution for 48 hours at 30--35 DEG  C., acidifying with hydrochloric acid, filtering off the precipitate and washing it with hot water.