Prote coating Chemistry
Aqueous solutions containing polyvinyl alcohol are applied to warp yarns to increase their strength and abrasion resistance during weaving. The pva size formulation consists of a specific blend of polymers and antistatic agents tailored for flax fibres. This chemical layer prevents the hairiness of the linen yarn from causing entanglements in the loom shed.
Chemical Application Process
In the sizing department, the warp yarns pass through a heated vat containing the liquid mixture before being dried on large cylinders. The viscosity of the pva size formulation must be carefully controlled to ensure even penetration into the yarn core while leaving a smooth film on the surface. Too much coating makes the yarn brittle, while too little fails to provide the necessary protection against the friction of the healds and reed.
Technicians adjust the concentration based on the yarn count and the complexity of the weave pattern.
Desizing Procedure Consideration
Polyvinyl alcohol is preferred in many Chinese linen mills because it is water-soluble and relatively easy to remove during the finishing process. After weaving, the pva size formulation is washed away in hot water to restore the natural softness and absorbency of the linen. The efficiency of this removal is critical for ensuring that subsequent dyeing and bleaching steps are uniform.
Effective sizing and desizing cycles are essential for maintaining high production standards.
