Film Modification
Chemical modification of protective yarn coatings involves adding specific agents to the sizing mixture to increase the elasticity of the starch film. In linen yarn preparation, size film plasticization is necessary to prevent the protective layer from cracking under the high tension of the loom. Starch alone forms a hard, brittle film that flitters and sheds during the dynamic motion of weaving.
Introducing plasticizing agents, such as animal fats, synthetic wax, or glycerine, softens the film and enhances its elastic recovery.
Coating Flexibility
Elasticity of the protective coating prevents the yarn from shedding starch and breaking during the intense mechanical stresses of shed formation. When proper size film plasticization is achieved, the coated flax or cotton warp yarn can stretch without rupturing the protective shell. This flexibility allows the yarn to absorb the rapid tension peaks that occur during the pick insertion.
Without adequate plasticizer, the starch film breaks off as fine dust, leaving the bare fibers exposed to friction. This dust accumulation can clog loom components and lead to frequent production halts.
Sizing Adjustments
Selecting the correct ratio of plasticizer to starch depends on the fiber type and ambient humidity of the weaving room. This balance ensures optimal weaving performance and yarn protection.
