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Talking about the points for attention in the dyeing and finishing of composite fabrics

In the domestic textile market in the past two years, the demand for moisture-absorbing and sweat-wicking textiles has gradually increased, which has attracted the attention of people in the industry. The uses of moisture-absorbing and perspiration fibers include pure spinning, or blending or interweaving with cotton, wool, silk, hemp and other chemical fibers and synthetic fibers; they can be woven or knitted, and have good development prospects.


The performance of moisture-wicking fabrics Moisture-wicking fabrics have deep dyeing properties. Because the surface of the moisture-absorbing and sweat-wicking polyester has concave and convex shapes and narrow grooves, the incident light can be diffused and absorbed by the fibers for many times, reducing reflected light, resulting in deep dyeing. The property is greatly increased, and the dyeing brightness and deep dyeing are improved.


Moisture-wicking fabrics also have low fuzzing and pilling. After Coolplus II is scouring by NaOH5-7g/L, 100℃-120℃ for 30 minutes, the polyester will lose part of the weight with alkali treatment (similar to alkali loss), and the fiber will lose weight. Its strength is also reduced, and its anti-pilling performance can reach grade 3. Based on the above reasons, the weave specification of Coolplus II should be properly designed to be tighter to prevent the fabric from being too loose after scouring.


Several Problems in Dyeing and Finishing The dyeing and finishing technology of moisture wicking fabrics (pure and blended) can basically refer to the technological process and technical conditions of conventional polyester and polyester-cotton blended fabrics. However, the special structure of the moisture-absorbing and sweat-wicking polyester must ensure that it will not be damaged, otherwise it will affect the performance of the product.



The main concerns are:
1. Moisture-wicking polyester is mainly special-shaped fiber, and most of the surface has a micro-groove structure. The surface area of ​​the same fineness is 20-50% larger than that of conventional circular fibers. Therefore, high-temperature alkali treatment in pretreatment should be carefully considered.


2. For the same reasons as above, disperse dyes dye quickly, so to dye cotton blended fabrics with good homochromatic properties, the original recipe for dyeing cotton (or dyeing polyester) must be properly adjusted.


3. When the moisture-absorbing and perspiring fabric is softened, it is not suitable to use hydrophobic varieties, otherwise it will affect the wicking effect of the fabric and reduce its moisture-absorbing and perspiring function. Moisture absorption and perspiration can be improved, and it is better to choose durable varieties.


4. The newly launched moisture wicking agent is mainly a compound of water-dispersible polyester as the main component. The source of the development of this additive can be traced back to the 1960s and 1970s by the British ICl company. Permalose to the market, where Permalose-T is used for polyester fabrics, and Permalose-TG is used for polyester-cotton blended fabrics.


Water-dispersible polyester is a block copolymer of terephthalic acid (ethylene glycol) and polyethylene oxide. Depending on the molecular weight and melting point of the block copolymer, the melting point is about 50-60 °C, and it is easy to disperse in water. It is gelatinous when the concentration is high. The molecular structure of the water-dispersed block copolymer has the same benzene ring as the polyester molecular structure. At high temperature, the molecular segments are anchored on the surface of the polyester, so that the polyester is changed from the original hydrophobic surface to a durable water-based surface.


The application methods of water-dispersible embedded copolymers include rolling baking process and high temperature dipping process. The former requires heat treatment at 160℃-170℃ for 3-5min, and the latter requires heat treatment at 130℃ for 30min. Ingredients) is about 1-1.5%, and the treatment effect is better and stable in the high-temperature dipping process. After the moisture-absorbing and sweat-wicking finishing, in addition to significantly improving the moisture-absorbing and sweat-wicking function, it also has antistatic and easy decontamination effects.