After the sizing, the improvement of the warp yarn performance should be enhanced, stretched, wear-resistant, and applied to the hairiness. The filaments are sizing, so that the individual filaments adhere to each other, have a bundle property, prevent the filaments from fluffing or breaking, and can inhibit the elasticity of the filaments, and are easy to operate. Short-fiber warp yarns and strong twist yarns also need to be sizing to suppress retraction for smooth production. The ultimate goal of sizing is: good pulp shaft, less weaving, low number of broken ends, high weaving efficiency, and improved warp yarn weavability.
The specific requirements are:
(1) Increase the breaking strength of the yarn. Appropriate increase in strength is necessary, but if the excessive increase in sizing strength is inevitable, it will inevitably make the yarn hard and brittle, lose its elasticity, and easily break the head. The cotton yarn reinforcement rate is generally controlled at 25% to 40%, polyester/cotton yarn l0% to 25%, pure polyester yarn 10% to 20%, polyester/viscose and pure viscose yarn >25%.
(2) Maintain the elongation at break of the yarn. The yarn yarn original yarn elongation is generally 7%, and should be kept at 4%-5% after sizing to facilitate weaving, so the elongation reduction rate is ≤30%, polyester/cotton, polyester/viscose yarn ≤25%, pure viscose yarn ≤ 35%.
(3) Improve the wear rate. Since the current wear test has not been standardized, the wear rates of various slurry formulations vary greatly.
(4) Hairiness reduction rate. Using YGl7lB yarn hairiness tester and BT-2 online hairiness tester, the yarn hairiness comparison before and after sizing, the advanced index of hairiness reduction rate is more than 75%.
(5) Shaft rate. It is required that the sizing yarn has no broken head, long head, sticky joint, twisted head, light pulp pilling, weaving without burrs, etc., and the advanced level has a good axial rate of 60% or more.
(6) The number of warp breaks on looms. Shuttle looms should be less than 1 /(platform h) and shuttleless looms require less than 10-15 weft breaks of 100,000 weft.
As a gray fabric for printing, dyeing and finishing, besides the requirement of weavability, it also requires easy desizing, and the desizing waste liquor has no pollution to the environment. It must be considered in the selection and proportion of slurry.
As a finished fabric, it is required to give the fabric a unique style and feel, and it must be adjusted appropriately in terms of sizing type, oil agent and sizing rate.