The main quality problems of Tencel fiber fabrics are uneven fluff, color aberration, color barrier, nephrite, color spot, crease, etc. The main reasons for the fiber fibrillation and wet expansion and variation in fiber dyeing properties are the fibers. . The control and utilization of fiber fibrillation should be strengthened, and appropriate textile dyeing and finishing processes, equipment and dyes should be selected to prevent wrinkles, reduce friction, extrusion and damage during post-processing.
Tencel fiber has the moisture absorption of natural fibers, the high strength of polyester fibers, the drape of viscose fibers and the feel of silk fibers. The product is made with good performance and stable size. Underwear, shirts, skirts, casual clothes, jeans, high-end knitted clothing and industrial products processed by it are deeply loved by consumers. The products have become popular all over the world. my country has introduced technology to mass production and has further replaced viscose fiber. trend. However, there are many product quality problems at present, and the overall level is not high. Among them, the more prominent ones are the whitening color difference, color barrier, and cotton particles defects; peach skin velvet fabrics have uneven fluff; blended and interwoven monochrome The color difference of fabrics is common; the creases, scratches, stains and other defects of thick fabrics are more serious. These defects are related to certain characteristics of Tencel fibers.
1 Analysis of Tencel fiber characteristics and product defects
1.1 Fibrillation on the fiber surface
Tencel fibers have high crystallinity and uniform fiber cross-section, but the bond between the fibers is weak and has no elasticity. If subjected to mechanical friction, the outer layer of the fiber will break, forming furry with a length of about 1 to 4 microns. Especially in wet conditions, it is more likely to occur, and in severe cases, it will also tangle into cotton particles.
Fibrosis has a dual effect. Uneven local fibrillation will cause uneven product appearance, resulting in quality differences, hue differences, and cotton particle defects.
The uniform production of fibrillation can make the fabric look suede, becoming a peach-skin velvet-style fabric, and also making denim clothes more natural and old. Using the fibrillation properties, nonwoven filter materials and special papers can also be made. It can be seen that the fibrillation problem must be controlled and utilized manually.
1.2 Wet expansion of fibers
Tencel fibers have high expansion properties and expand up to 40% in water. This gives the fabric excellent drape and smooth dynamic feeling, but it will make the fabric hard in wet state, especially medium-thick fabrics with larger weight per unit area. This makes the fabric prone to defects such as creases, scratches and stains in dyeing and clothing processing, and these defects have a strong “memory” and will be preserved for a long time.
1.3 Dyeing properties of fibers
Tencel fibers expand greatly after encountering water, and dyes and additives are prone to enter the fibers, so the initial dyeing rate is quite high, which can easily cause color difference between front and back and left and right. In terms of dye selection, the dyes are selected. Variety with high initial dyeing rate should be selected, and the color difference should be controlled by adding salt multiple times and adding alkali multiple times. Its color yield is greater than that of ordinary natural fibers; it is more difficult to dye blended and interwoven fabrics in the same color, so it must be takenConsider strict control of hue.
Dyeing will have an impact on fibrillation, so it is crucial to control the movement of ingredients and dye liquid. Fibration can be controlled by dyeing processes. Due to the presence of surface fibrillation, the stainability may be low on the surface.
When the two-step dyeing of Tencel fiber and wool is used to dye each other, the two fibers have a problem of mutual staining. When it is blended with wool, when it is dyed with reactive dyes and weak acid dyes, the strength of the blended yarn will decrease significantly, affecting the normal weaving.
2 Control and utilization of fibrillation
2.1 Selection of Tencel fiber
Tencel fiber has two models: G-100, which are standard, which are prone to fibrillation. The A-100 type is not easy to produce fibrillation, but its strength is slightly less than 10%. It is more suitable for ordinary dyeing and finishing technology, especially for knitted fabrics, but it cannot produce peach velvet style. Lyecell’s filament fiber Newcell is reported to not produce fibrillation and can be used to interweave with other fibers.
2.2 Effect of yarn and fabric structure on fibrillation
With fabrics with relatively high yarn twist and tight structure, the ends of the short fibers can be firmly bonded into the fabric. In the future, during the wet treatment process, There is a smaller tendency to fibrillation and pilling. Generally, the twist coefficient of ring spindle yarn can be increased to 350~370, and the fur of rotor yarn itself is less used.
2.3 The influence of spinning process on fibrillation
Chemical fibers are generally equal in length, with very low staple fiber ratio, and much less yarn-forming hair feathers than pure cotton, but if the spinning process is improper, it will cause short fibers The rate and hairy feather increase significantly; this is a potential crisis of fibrillation in fabric or garment dyeing and finishing. Breakage, damage, especially fine denier fibers during spinning, are prone to occur, which is the fundamental reason for the increase in the rate of short fibers and hairy feathers.
2.4 The influence of dyeing and finishing process on fibrillation
2.4.1 The influence of dyeing and finishing process on fibrillation
The common dyeing and finishing process flow of Tencel fiber fabrics is as follows:
Among them 1. Suitable for general smooth fabrics, it can be free from primary fibrillation and secondary fibrillation. 2. Suitable for peach skin velvet fabrics, it is generally necessary to perform primary fibrillation first to release the ends of short fibers with different lengths inside the yarn as much as possible, and then remove the fibrils by enzyme treatment, and then dyeing and perform secondary fibrils. Fibre to obtain a peach-skin velvet style with uniform and neat hair.
2.4.2 Control of fibrillation before dyeing
Boiling is the basis for eliminating fibrillation. After burning, it sometimes causes wrinkles in the center of the fabric, so the burning hair can be moved to desizing. conduct.
Cacutone merceration treatment can be added before primary fibrillation to improve the gloss and dyeing properties of the fabric, and can also reduce the impact of fiber fibrillation and the possibility of creases during rope dyeing. However, Tencel fibers are alkali-resistant to It is poor in nature and should be treated with a low alkali cold reactor.
Fibrillation is generally achieved by rubbing and rubbing by dyeing machinery under wet conditions.Fleece fabrics can also be obtained by using a mechanical fleece grinder or a gold steel sander before or after dyeing to obtain fibrillation.
Removing the fibrils is generally solved by the enzyme treatment process, and enzyme preparations with better effects should be selected. Acid enzymes should be used for 100%Tencel fabrics; neutral enzymes should be used for textiles blended with cotton and linen, and both need to be reasonably set to achieve sufficient removal of fibrils and less strength of the fabric.
2.4.3 Dyeing equipment and fibrillation
Tencel fiber fabric dyeing methods are many, and flat-web dyeing equipment (coiling machine, cold rolling stack, rolling dyeing, etc.) are generally not easy to produce fibrillation and Wrinkle markings are suitable for general smooth fabrics. Rope dyeing equipment (air flow dyeing machine, overflow dyeing machine, etc.) is prone to fibrillation and is more suitable for peach velvet fabrics. Airflow dyeing machines are generally recommended abroad, which can withstand sufficient friction and continuously change the contact surface; after adding smoothing agent, it can also prevent the occurrence of creases, and can also undergo continuous primary fibrillation of fabrics, enzyme treatment, dyeing, etc. Functions, such as after-use finishing and drying and dispensing machines, can reduce the tendency of fibrillation after processing, making the product soft and plump.
2.4.4 Dye selection and fibrillation
Tencel fiber fabrics can use direct, active, naftu and other dyes, but more reactive dyes are used. If selected, they can form intersect with the fiber molecular chain. The bi- or tri-active dyes of the combination can reduce or prevent the impact of fibrosis in dyeing; on the contrary, if a peach-skin-style product is to be produced, a mono-active dye should be used.
2.4.5 The influence of resin finishing on fibrillation
Resin finishing is the main process of dyeing post-treatment. It can reduce the swelling and anti-warming effect of Tencel fibers; it can also reduce the wet hardness of the fabric and avoid the tendency of fibrillation in the future. However, the amount of resin should not be too high, otherwise fiber brittle points will be formed, resulting in new fibrillation phenomena, which is also unfavorable for the long-term maintenance of peach velvet. By adding softeners such as amino silicone, fibrillation brittleness can be reduced, the surface properties of the fabric can be improved, and the strength of the fabric can be reduced due to resin finishing.
3 Color difference control of Tencel fiber
The color difference problem of Tencel fiber blended and interwoven products is more prominent. The same color dyeing must be consistent in the two-component fiber dyeing and consistent in the color light and color fastness. To this end, we need to carefully screen the dyes, determine the color difference value of the two fibers, and control the average value of the color difference of each dye with better color properties. When using disolvation method to dye, add anti-dyeing agent to prevent staining. Some factories use loose fibers to dye separately, which can shorten the dyeing time and solve the contradiction between the mutual influence of the two types of fiber dyeing environments, and can meet the rich and comprehensive color hue of the product. In short, high color measurement and dyeing technology and strict Only by managing measures can the consistency of color.
4 Prevention and control of defects such as creases, abrasions, and stains in weaving, dyeing and garment processing
It has been explained before that due to the wet expansion of Tencel fibers, the fabric is promoted.The body becomes hard and is very likely to cause defects such as creases, scratches, stains, etc. after friction, pressurization and folding, especially thick fabrics such as denim. This type of defect is not easy to detect in future processing, but it is very obvious after washing water and is not easy to eliminate. Therefore, prevention must be emphasized.
4.1 Basic points for reducing defects such as creases, abrasions, and stains
(1) To improve the wet expansion of fabrics, you can use Tencel fibers and fibers with less water expansion, such as polyester, nylon, etc. to improve the wet expansion of fabrics. , interweave, and appropriately reduce the density of the fabric warp and weft yarns.
（2）Grey fabric minimizes defects such as cross gears, side braces, creases, dense roads, etc. to prevent local hardness and damage of the fabric.
(3) Try to use roll packaging, without folding or binding with ropes to reduce indentation and crease.
(4) Reduce various physical pressures and frictions artificially on grey cloth, finished cloth, and clothing, and try to prevent damage and puncture of fabrics, nail pressing, knife cutting, etc.
(5) To prevent wrinkles and rubbing during dyeing and finishing, a small amount of smoothing agent and softener should be added.
(6) Use dyeing and cleaning equipment with large drum diameter and low rotation speed to enable the fabric to move freely and reduce wrinkles and abrasions caused by friction and agent pressure.
4.2 Main measures to prevent such defects in clothing processing
(1) Use scissors when cutting, instead of knife;
(2) Do not use pins, staples or clips when tenting. Use spray glue or adhesive paper;
(3) When garment storage or semi-products are transported, try to lay or hang them as flat as possible to avoid flip marks;
(4) Adjust the pressing foot pressure and cloth feeding teeth during sewing It should be correct, do not pull before pushing; use a garden needle, no pointed needle; the wear of the car needle should be replaced in time. The suture density should be controlled to prevent wrinkles from occurring at the seam. Do not use lining on the placket. Cut the sutures, don’t pull them.
(5) Use hot water and smoothing agent when washing clothes, and control the quantity not to exceed 80% of the capacity, and control the temperature and time.
(6) It is recommended to “unsolution-free resin finishing” to avoid crease defects during ironing.
5 Conclusion
(1) Tencel fiber products are environmentally friendly products that conform to the trend of the times. Due to its excellent performance, they will definitely be popular around the world. Although the price is high at present, as the output increases, With the improvement of process and improvement, the price will inevitably decline. It is expected that all or most of the viscose fibers with severe pollution and poor performance in the future will be replaced.
(2) The fibrillation problem of Tencel fibers is the key to dyeing and finishing. In order to avoid fibrillation or use fibrillation to produce peach velvet fabrics, appropriate dyeing and finishing processes, equipment, dyes and fiber varieties must be selected.
(3) The dyeing and finishing process should be based on the fabric raw material structure (Tencel fiber pure spinning, blending, interwoven), fabric structure (density, gram weight), and fabric categories (woven fabrics, knitted fabrics, peach velvet weaving) correctly selected.
(4) The key to Tencel clothing processing is to prevent defects such as creases, scratches, and stains. For this reason, it is necessary to avoid fabric folding, friction, extrusion and damage.
(5) In view of the special requirements of Tencel fiber dyeing and finishing, it is recommended to adopt a closed production and dedicated management model.
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