| 摘要 |
In the dyeing, bleaching and finishing of webs of natural or synthetic textile materials, e.g. cellulosic fibres, by impregnation of the materials with aqueous compositions containing dyeing, bleaching or finishing agents, the materials are heated to effect vaporisation of the residual moisture contained therein and are contacted with the aqueous impregnation composition while the moisture is in the vaporized condition. The transition, from the heating zone to the impregnating liquid is preferably brief so that recondensation of the water vapour contained in the pores of the web is prevented or the intervening zone may be bridged by a steam-filled passage preferably extending fully into the impregnating liquid. The web may first be subjected to condensation heating to vaporisation temperature in a steam or steam/air atmosphere to deposit moisture on the material, such condensation heating when applied to dry textile webs heated to a temperature of 20-100 DEG C yielding 5.5% additional moisture, with reference to the bone dry weight textile material, condensed on the web. Vaporisation which then follows condensation heating is effected by condensation-free heating or heating by direct contact between the web and a heated drum. |
