Line fabric, with its simple and natural style, has the advantages of moisture absorption, breathability, and coolness. Well received by the international market. However, due to the characteristics of the flax fiber, soft finishing of linen fabric is much more difficult than that of cotton. The following is a discussion on the characteristics of flax fiber and the softening and finishing methods of flax fabric.
1. Characteristics of flax fiber:
In textile fiber classification, Flax belongs to cellulose fiber among natural fibers, and among cellulose fibers, flax belongs to bast fiber. Because the flax single fiber is short, its length is 22-38mm (the length of cotton fiber is 25-45mm), so the flax single fiber state cannot be spun. During the bleaching process, it cannot be completely degummed, but can only be partially degummed, leaving a part of the glue. The quality bonds several single fibers together to form technical fibers that meet the requirements of spinning length, which are so-called bundled fibers. The presence of these colloids is one of the reasons why linen fabrics feel hard.
Flax fiber has high crystallinity (about 70%) and high orientation. The intersection angle between the fibril and the fiber axis is less than 10 degrees, so the elongation at break is small (the intersection angle between the fibril and the fiber axis in cotton fiber is 20-30 degrees between) The breaking elongation of the fiber reflects the flexibility of the fiber. Taking 24-count linen yarn as an example, the breaking elongation is 4.2%. Taking 21-count cotton yarn as an example, the breaking elongation is 7.7%, so flax is more rigid than cotton. .
In summary, the reason why linen fabric feels hard is mainly because the bundled fibers contain part of colloid; the flax fiber has high crystallinity and high orientation, so the elongation at break is small, showing high rigidity. Little flexibility.
2. Methods to improve the feel of linen fabrics
According to the characteristics of flax fiber and combined with our factory’s many years of production practice, improving the texture of linen fabrics can start from the following aspects:
2.1 Strengthen fabric pre-treatment.
Flax fiber contains more impurities, about 30%, and needs to be bleached. Remove gradually during the cloth process. Considering the damage to the fiber, it is impossible to completely remove impurities in the bleaching process. Re-bleaching after mercerization has a significant effect on improving the feel of linen fabrics. It can further remove impurities in the fabric, reduce the cohesion between fibers, and make the fibers more comfortable. Relatively loose and soft to the touch.
2.2 Biodegradation method.
Use cellulase to interact with flax fibers to destroy the orderly arrangement in flax fibers, change larger molecular chains into smaller molecular chains, reduce fiber orientation and crystallinity, and increase The elongation of large fibers at break increases their softness and improves the feel of the fabric. Through practice, we feel that simply using cellulase to improve the feel of linen fabrics is not very effective.
2.3 Add softener.
Adding softeners is an important way to improve the feel of linen fabrics. In principle, any softener used for cotton can be used for flax. However, due to the characteristics of flax, processing flax using the method of processing cotton is far from meeting the hand feel requirements. In addition to increasing the dosage, it is important to choose the softener. We also need to work hard on variety. Our factory’s approach is to mainly select reactive softeners, and select different types of softeners according to different colors, such as white, and non-ionic softeners that do not turn yellow. This type of softener has a general feel. The dosage is larger, the general concentration is: 60-80g/1; for sensitive colors, such as navy blue , coffee, scarlet, etc., use softeners based on amino silicone and compounded with weak cations. Amino silicone softeners have a good hand feel, do not react with dyes, and do not cause problems. The disadvantage is that they are easy to stick to the roller when used continuously, and There is a black gelatinous substance that sticks to the cloth surface. It can be used in combination with weak cations to improve the roller sticking situation. The concentration is: about 30g/1, and the compounding ratio is 2:1; for general colors, a weak cationic softener is used, which has a better hand feel. The concentration is about 20g/1, but it is easy to mess up some sensitive colors.
2.4 Pre-shrinking.
When linen fabrics are pre-shrunk, they can not only control the shrinkage rate, but also stretch and rub the fabrics with rubber blankets, making the fabric tissue more fluffy, softer and fuller to the touch.
2.5 washed and finished.
In order to meet the special requirements of customers, linen fabrics are washed and finished. The fabrics are washed first, Spin drying, drying in a drum-type hot air dryer, the fabric is constantly turned over in the dryer, and the high-temperature hot air enters the inside of the fiber to make the fiber fluffy., the fabric has become thicker, the surface has become velvet, and the hand feels very plump.
Among the above hand finishing methods, our factory commonly uses the following three combinations:
(1) Strengthen pre-treatment, especially re-bleaching after mercerization.
(2) Choose different types of softeners according to different colors, choose non-ionic for white; choose amino silicone for sensitive colors It is a softener compounded mainly with weak cations; the general color selection is weak cationic.
(3) Pre-shrunk finishing, while controlling shrinkage, improves the feel of the fabric.
In recent years, our factory has an annual output of 5 million meters of dyed fabrics, most of which are exported to the United States. The above methods are used to basically meet customer requirements. Other finishing methods can be made when customers have special requirements.
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