What is the objective of warp sizing? The ultimate goal of sizing is a better sizing beam, fewer weaving defects, lower number of ends, higher weaving efficiency. More detailed requirements are as followed.
“a slurry with adhesive material as the main body is applied to the warp yarn, which acts on the surface of the warp yarn to a certain depth, and after drying, it forms a sizing structure that integrates the size and the yarn.”
1 Increasing yarn breaking strength
It is necessary to increase the strength appropriately, but if being increased too much, it will inevitably make the yarn hard and brittle, lose its elasticity, and easily break. The reinforcement rate of pure cotton yarn is generally controlled at 25%-40%, polyester/cotton yarn 10%-25%, pure polyester yarn 10%-20%, polyester/viscose and pure viscose yarn>25%.
2 Maintaining yarn elongation at break
The elongation of raw cotton yarn is generally 7%. After sizing, it should be kept at 4%-5% to facilitate weaving. Therefore, the elongation reduction rate is ≤30%, polyester/cotton and polyester/viscose yarn ≤25%, and pure viscose yarn ≤ 35%.
3 Improving the abrasion ratio
As the current wear resistance test has not been standardized, the abrasion ratio of various sizing formulations is also very different.
4 Hairiness reduction rate
Using YG17lB yarn hairiness tester and BT-2 online hairiness tester to compare yarn hairiness before and after sizing, the index of hairiness reduction rate is more than 75%.
5 Good warp beam rate
It is required that the sizing has no broken ends, no long ends, no sticking, no twisted ends, no light sizing, and no fuzzing or pilling, and no edge pulling or other defects in weaving. And the advanced level of good warp beam rate is above 60%.
6 The number of broken warps in looms
The number for one set of shuttle looms should be under 1pcs per h And for shuttleless looms with 100,000 wefts, the number of broken warp should be 10-15 pcs or less.
The improvement of warp performance after sizing should lie in strengthen, maintain elongation, wear resistance, and hairiness. Through sizing, the single filament adheres to each other, which can prevent the filaments from fluffing or breaking, and can inhibit the elasticity of the filaments, which is convenient for operation. Spun warp stretch yarns and strong twisted yarns also need to be sized to prevent shrinkage, then they can be produced smoothly.
The water-soluble polyester resin by Decon can guarantee the super coating and infiltration property of various sized yarn. The intact sizing film rate can reach 75% or above.
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