| 摘要 |
1,174,797. Reduction of vat dyes with borohydrides. VENTRON CORP. 7 April, 1967 [14 April, 1966], No. 16039/67. Heading D1B. In a process for vat dyeing using a solution containing an alkali metal borohydride and an alkali metal hydroxide together with an alkali metal nickel cyanide, the alkali metal borohydride and alkali metal nickel cyanide are reacted in absence of the vat dyestuff in concentrated solution in presence of at least one mole of alkali metal hydroxide per mole of alkali metal borohydride for a sufficient time so as to obtain an intense reddish brown colour in the concentrated solution, the concentration of the concentrated solution being substantially greater than that used for the subsequent vatting of vat' dyestuff. Preferably 5 to 25 parts by weight of alkali metal hydroxide per part of alkali metal borohydride are used, the preferred temperature is room temperature to 100‹C and the concentrated solution is 20 times greater than that used for vatting. Dyeings on ' cellulosic materials are obtained e.g. mercerised twill, mercerised poplin and unmercerised nettle. |
