The dyeing and finishing process of polyester products
Through the continuous improvement of polyester fiber, polyester products have been more and more favored by everyone. Polyester is widely used in knitting, home textiles, industrial and other industries, the demand is very broad.
Process flow of ordinary polyester (low twist or medium twist) fabric:
Cloth preparation → pre-treatment bleaching (whitening)→ washing → dehydration → drying → Setting (finishing)→ inspection and packaging
Process flow of ordinary polyester (high twist) fabric:
Cloth preparation → Pre-shrinking → preordering → reducing → pre-treatment bleaching (whitening)→ washing → dehydration → drying → setting → inspection
Description of process
1. Spare cloth: select, weigh and sew the blank cloth.
2. Pre-shrinking: The pre-shrinking process is required when the polyester strongly twisted fabric is processed, and the pre-shrinking process is completed in the dyeing equipment. The pre-shrinkage temperature of strongly twisted fabric is higher than that of elastic fabric, up to 130℃. During pre-shrinking, refining agent can be appropriately added to remove various impurities from the fabric. However, the temperature is too high, and the refining agent added during the pre-shrinking is easy to peel off the magazine on the inner wall of the dye VAT, causing pollution to the fabric, and finally affecting the whiteness. In order to improve the deimpurity effect in pre-shrinking stage, an appropriate amount of liquid alkali can be added during pre-shrinking.
3, reservation: strong twist fabric temperature is slightly higher, generally not more than 200℃. The determination of speed is not only related to the thickness of the fabric, moisture content, but also to the length of the setting machine.
4, reduction: strong twist fabric after the scheduled reduction can be completed in the reduction machine, can also be completed in the reduction cylinder. Reducing machine intermittent rope type reducing is easy to control the fabric feel and strength damage. Decrement can be appropriate to add a decrement accelerator.
5. Pretreatment bleaching: the bleaching and whitening of common polyester fabric is usually done in one bath. The temperature is less than 130℃, and the holding time is 40min.
6, washing: before the fabric out of the tank, it is best to add a pickling, which can ensure the feel of the fabric, and can also be washed in general.
7. Drying: Generally, dip rolling stretch drying method is generally adopted, the temperature is controlled at 160-180 ℃, and the time is 30-60s. It can also be dried directly.
Notes for dyeing polyester fabrics
Strong twist fabric needs reducing processing and bleaching and whitening processing. Ordinary fabric can be bleached and whitened by one-bath method by increasing the temperature during refining. When dyeing polyester fabric, the general temperature is controlled at 110 -- 130℃. Generally, when it is 102 -- 110℃, it is easy to produce dye aggregation. If the aggregation is adsorbed by the fiber, it is easy to produce stain, so it should be heated up quickly at this temperature.
Notes for pretreatment and processing of polyester fabrics
1. The grey cloth should not be stacked for too long, so as not to cause uneven internal stress of the fabric and affect the stability of the door size.
2. The temperature of pre-shaping should be controlled below 200℃.
3, bleaching and whitening can also be appropriate to extend the holding time, increase the process temperature.