Surface Tension
Chemical additives reduce the cohesive forces of a liquid to allow it to spread across a solid surface. The wetting agent concentration in a flax treatment bath determines how quickly the moisture can penetrate the naturally waxy exterior of the fibre. Without these surfactants, the liquor would simply sit on the surface of the bundle.
A balanced solution ensures that every fibre in the batch receives the same level of treatment.
Penetration Rate
Rapid absorption is necessary for the efficiency of continuous bleaching and dyeing ranges. If the wetting agent concentration is too low, the core of the yarn may remain dry, leading to patchy results. Increasing the amount of agent can speed up the process, but excessive levels may cause foaming or interfere with other chemicals.
The optimal level is found through laboratory trials for each specific fabric type. High speed lines are particularly sensitive to these settings because the time for absorption is extremely short. Testing is performed with a standard drop test on the fabric surface.
Bath Exhaustion
Monitoring the level of surfactant is necessary to maintain consistency over long production runs. As the fabric passes through the liquor, it carries away a portion of the chemicals, which alters the wetting agent concentration over time. Automatic dosing systems add fresh agent based on the volume of fabric processed.
This constant adjustment prevents the treatment from becoming less effective as the day progresses.
