Pre - treatment of Modal fabrics?

Viscose and Modal fibers are supplied in the pure state and with an incomparably higher degree of whiteness than cotton. Bleaching processes are, therefore, only required for completely white products (reduced quantities of chemicals) or pastel shades.
While tending to be unaffected by the usual chemical concentrations, viscose and Modal fibers react rapidly and intensely on coming into contact with alkali. Both fiber types are capable of being activated by a lye concentration of 4.5% (7°Bé) to such an extent that a distinctly higher dye absorption results.

While a concentration of 4.5% NaOH (7°Bé) represents the upper limit as far as viscose fibers are concerned, Modal fibers can, leaving aside the critical range of 7% to 15% NaOH, be treated with mercerizing lye of 17% to 22% (24–28°Bé). For bleaching products the temperature should not be allowed to exceed 180°C, e.g. heat-setting of blends with PES. Prior to thermal reaction, the fibers must be generally free of alkali residues.

Pre - treatment receipe for white products:

Setabicol BAC :6 g/L

Setalub ACA :1 g/L

Hydrojen Peroxide (50%) :4 g/L

Temperature : 90 - 98°C

Time : 45 - 60 min.


Note: Creases can occure if material is wet and wait. Centrifugal machine should not be used at any stage and it must be dried immediately after all wet processes.