Problems that are common in yarn mercerization include mercerized flowers, yellow spots, brittle damage and random yarns.
(1) Mercerized flower: The yarn cover is not fully flattened and straightened, the yarn is tied too tightly, the yarn is broken, and the yarn moisture content is inconsistent or partial. Air drying, the tension of the yarn covering roller of the mercerizing machine, the roller pressure, the concentration and temperature of the mercerizing alkali solution are uneven, the alkali solution contains a large amount of calcium ions or magnesium ions, and the water washing or pickling after mercerization is not timely, sufficient, and uneven. It is easy to cause mercerizing defects. Mercerized flowers are generally not easy to find in appearance and can only be discovered after dyeing. If the main cause of mercerized flowers is mercerization, mercerization can be performed again.
(2) Macular blemishes: If the mercerizing liquid is contaminated with iron, the generated iron hydroxide will adhere to the yarn, which will cause macular blemishes. Macular blemishes are generally easy to spot on the outside. It can be removed by treatment with 2~3g/L oxalic acid solution at 50~60°C.
(3) Brittle damage: The yarn after mercerization is not washed in time and air-dried with alkali; it is not washed in time after washing and air-dried with acid; it is not washed after pickling. 7, Drying with acid can easily cause yarn brittleness.
(4) Random yarn: If the hollow tube or rotary device of the jet-type hank washing machine is not smooth enough, or the operation is careless, the cotton yarn can easily become entangled in the hollow tube. on, causing random yarn defects. Slightly messy yarns can be patiently separated and used, but severe ones cannot be undone. </p
