GB484991A - Method of treating napped or like face finished fabric - Google Patents

Abstract

Napped fabrics are dyed and finished in a continuous process by passing them at constant rate relative to, and in brief contact with, a vehicle containing a dyestuff having a low exhaustion rate to impregnate the fabric with the dyestuff containing vehicle, forcing the dyestuff-containing vehicle into the fabric and removing excess thereof by pressure, as by means of press-rolls, and completing the fixation of the dyestuff on the fibres while in transit to finishing devices. The rate of exhaustion of the dyestuff is related to the initial concentration of colouring matter per unit volume of the vehicle. The exhaustion rate is maintained substantially constant between 2 per cent and 15 per cent, and the time of contact may vary between ,03 minutes to 2 minutes. The concentration, temperature, pH value and volume of the bath are maintained constant. The fabric may have both animal and vegetable fibres or their synthetic equivalents in the backing or in the pile or in both, the dye bath then containing dyestuffs which colour uniformly, or complementary dyestuffs may be used one of which has a greater affinity for vegetable than for animal fibres and the other reverse, in such combinations as will produce the required similar or contrasting effects simultaneously. The several dyestuffs are so proportioned in the rehabilitating liquor added to the dye bath as to maintain the concentration of each substantially constant, their rates of exhaustion and relative concentrates being independently determined. The dyestuff vehicle may vary and may be made in the form of a paste by thickening with a water soluble or water dispersible thickener. The vehicle may also contain salts capable of dissociation by heat or steam to release acids or acid vapours or gases capable of reacting with dyestuffs to promote exhaustion into and fixation of dyestuff in and on the fibres. Gaseous vapours or gases may be substituted for or combined with the steam employed in the apparatus for fixing the dye. Suitable dyes may include direct dyes or neutral wool dyes or other dyestuffs depending on the character of the fibres. After fixation or ageing, the exhausted vehicle and any thickener employed is washed from the fabric in a continuous washing operation, the rate of feed of the fabric throughout all the continuous dyeing and finishing operations being from 10 to 30 yards per minute, a certain amount of slack material being provided between certain operations as a reservoir. After washing, the fabric may be treated with acids, or acid materials, metal salts &c. to improve the fastness of the dye, and, after rinsing, hydro-extraction and raising, napping or opening &c. as by tigering, it may be dried in a continuous type of drier. After drying, the material passes continuously at the same rate through synchronized pile-finishing apparatus comprising raising or opening apparatus, nappers, or tigers, beating, shearing, brushing, humidifying, inspection and packing apparatus.