Fabric Fading Problems
Pigment dyes are dispersed in a gluey resin and spread across the top of the fabric surface. They can either be printed (screen or roller) as a single uniform shade all over; or applied in several colours to form multi-coloured patterns.
After application the print is passed through a heated oven which bonds the gluey resin onto the woven fabric by surface adhesion to the exposed yarns. There is not usually very much physical adhesion in that the resin does not flow into the yarns and lock around them. Curing time and temperature are critical if a good bond is to be achieved.
There are various ways of avoiding fading problems:-
- Abrasion in use will cause progressive breakdown of a pigment print whenever it is rubbed. This can be a particular problem on the arm of an upholstered chair; on the edge of a fitted bedspread or on the leading edge of a curtain handled twice a day for opening and closing.
- The print can be washing off by the use of too much mechanical action in laundering. There is a big difference in the mechanical action associated with different wash processes and the bar or broken bar beneath the washtub symbol on the care label indicates the precautions needed. This is every bit as important as wash temperature.
- Washing at a higher wash temperature than that specified on the care label tends to cause softening of the resin so that more is rubbed off than it is at lower temperatures. This means that it is difficult to put pigment printed linen through a process which incorporates an implied thermal disinfection stage because this calls either for three minutes at 71˚C or ten minutes at 65˚C.
- Incorrect ironing will cause rapid breakdown of certain pigment prints depending on temperature resistance of the resin used. Repeated abrasion at the wear edges during ironing will cause white lines or white bands at the folds and double thickness points. This is not always immediately obvious because the resin is pushed into the weave without colour loss. However; the progressively broken down resin then becomes washed off in the next laundry process to reveal the characteristic and excessive fading.
- Ironing temperature is probably more critical than ironing abrasion and some resins can only safely withstand a one dot iron (110˚C).