Standard Linen Yarn Tensile Specifications for Weaving Preparation
Wet-spun linen warps demand a minimum tenacity of 18.5 cN/tex with under 1.2% beaming stretch to maintain loom stop rates below 1.5 per 100,000 picks.
PVA Size
Adhesive Coating
Sizing agents applied to warp yarns before weaving form a protective film that enhances tensile strength and reduces friction. The use of pva size is common in processing linen yarns because the synthetic polymer provides excellent adhesion to flax fibres. This coating prevents the hairy fibres from clinging and tangling during the shedding process, ensuring smooth loom operations.
Loom Performance
Applying the protective polymer coating involves passing the yarn through a heated chemical bath before drying it on heated cylinders. The increased yarn strength and smoothness allow high-speed looms to operate with fewer warp breaks, which boosts the productivity of the weaving mill. Unlike starch, pva size does not become brittle in low humidity, making it ideal for the variable environmental conditions found in weaving sheds.
This stability ensures that the warp yarn retains its flexibility under high mechanical stress.
Desizing Requirement
Finishing processes must completely remove the synthetic polymer before dyeing or bleaching to ensure uniform chemical uptake. Wet-processing mills wash the woven fabric in hot water, as the compound is highly soluble and easily extracted without harsh chemicals. Ensuring complete removal of pva size prevents blotches and uneven coloration in the finished linen fabric.