Abstract: Bamboo fiber velvet fabric is made of bamboo fiber/cotton blended yarn and polyester fiber. The company’s technical personnel have developed and innovated many aspects of their dyeing and finishing technology based on some characteristics of bamboo fiber and velvet fabrics. Finally, this bamboo fiber velvet fabric was successfully developed and recognized by customers.
With the improvement of living standards, people are eager to return to nature, and their awareness of environmental protection and health care is getting higher and higher. , the requirements for clothing fabrics are becoming higher and higher. The previous single fabric varieties such as pure cotton or polyester cotton can no longer meet the requirements of consumers, so a series of fabrics such as modal, viscose, soybean fiber, bamboo fiber, etc. High-quality fiber fabrics with environmental protection and health care functions are becoming more and more popular among people. These special new fiber fabrics bring high economic benefits to textile and garment enterprises due to their high added value. At the same time, due to the particularity of these new fibers, they often bring some problems to the production of enterprises, especially dyeing and finishing processing. technical challenge.
1 Fabric Development
1.1 Fabric Organizational Structure
32/1C35 bamboo 65+75 D/36F velvet. Cotton fiber accounts for 29.5%, bamboo fiber accounts for 55%, and polyester fiber accounts for 15.5%. The ground yarn is 75 D/36F, and the loop yarn is 32/1C35 bamboo 65 blended yarn.
1.2 Characteristics of Bamboo Fiber
This kind of velvet uses Bamboo fiber is bamboo pulp fiber, which is made by beating bamboo into pulp and then spinning it. Its processing method is similar to that of viscose, so it has some characteristics of viscose. It is precisely because of this special processing method that this bamboo pulp fiber is different from ordinary bamboo fiber. The breaking strength, elasticity and dyeability of the fiber have been reduced to a certain extent, which brings certain difficulties to the dyeing and finishing process. However, this kind of bamboo pulp fiber still has some advantages of ordinary bamboo fiber: it has good air permeability, moisture absorption and release, strong wear resistance, good drape and wearing comfort, and it also has the characteristics of ordinary bamboo fiber. antibacterial health benefits.
1.3 Features of the fabric
This bamboo fiber velvet fabric is It is because the weaving of bamboo fiber gives the fabric more excellent functions: the fabric has the characteristics of soft, smooth, shiny, good moisture absorption and breathability, and good drape. Compared with ordinary polyester-cotton velvet varieties, this kind of bamboo fiber velvet Especially the suede gives it a silky feel.
1.4 Dyeing and finishing technology of fabrics
The combination of bamboo-cotton blended fiber and polyester brings special functionality to this new type of velvet fabric, but at the same time, this new type of fabric also brings technical difficulties to the dyeing and finishing process. The company is relatively mature in the dyeing and finishing process of traditional polyester-cotton velvet, but this process is not suitable for bamboo fiber velvet. Due to the decrease in breaking strength and elasticity of bamboo pulp fibers and the intolerance of bamboo fibers to alkali and oxidants, the dyeability of fabrics is reduced, resulting in the suede of fabrics processed by conventional processes being very unsightly: the suede is messy and irregular, and the cloth surface is The creases are severe and there is no velvet look at all. To this end, based on the characteristics of this bamboo fiber velvet, the company optimized and developed and innovated the process from dyes, auxiliaries, dyeing processes, finishing processes and equipment, and developed a complete set of processing techniques to solve the problem. The quality problem of the fabric was eliminated, and a new type of bamboo fiber velvet fabric was successfully developed.
The comparison between the old and new process flows is as follows:
a. The old process flow
Weaving → opening → ring drying → shearing → seaming → dyeing → dehydration → ring drying → shearing → shaping.
b. New process flow:
Weaving direct opening Roll → shake cloth and leave for 24 hours → 130°C ring drying → shearing → pre-shaping → seaming → dyeing → dehydration → whole pile → drying → shearing → shaping.
1.4.1 Weaving
Required after the weaving machine is Directly open the roll to avoid coil clutter caused by long-term storage and extrusion of the blank fabric, and reduce fabric creases.
1.4.2 Leave the blank for 24 hours after shaking the cloth
The blank is shaken After opening the fabric tube, let it park in a natural state for 24 hours to allow the fabric blank to fully shrink evenly, ensure that the blank is in a stable and uniform state before proceeding to the next process, and reduce quality problems such as creases, uneven shrinkage, and uneven weight of the gray fabric.
1.4.3130℃ ring drying
Tumble drying was used before The machine rolls the blank at 90°C once before shearing. The production efficiency is very low and the effect is not very satisfactory. Now the air softener is used to 130°C ring drying for 30 minutes, the production efficiency has been greatly improved, and now it is switched to 130°C high temperature ring drying, so that The ground yarn polyester yarn shrinks and grasps the loop yarn, which greatly reduces the problem of loop yarn falling off after shearing.
1.4.4 Blank shearing
After ring drying at 130℃ The loops of the blanks should be in the same direction and stand up. Use a shearing machine to cut the loops. The shearing should be sufficient to avoid missing cuts or unequal shearing caused by blunt shearing knives. This step is critical and directly determines the final velvet effect.
1.4.5 Preforming
Previously made polyester-cotton velvet blanks After shearing, it is dyed directly without pre-shaping, because the elasticity of bamboo fiber is reduced.��Pre-shaping before dyeing can make the bamboo fiber as stable as possible before dyeing. Through comparative experiments, the effect of the pre-shaped cloth surface is significantly better than that of the non-pre-shaped cloth surface. The suede surface of the fabric is smooth, flat and not messy.
The specific process is as follows:
8 boxes of shaping machine
Temperature l90℃
Vehicle speed l8 m/min
Air volume 100%
Overfeed 20%
1.4.6 Seaming
Sewing after pre-shaping, with the suede side facing inward, this can reduce the lint of the fabric. The friction of the surface in the dyeing machine and the impact of the dye liquor on the suede surface.
1.4.7 Dyeing
a. Improvement of pre-treatment process
Due to the characteristics of bamboo pulp fibers that are not resistant to strong alkali and oxidants, the old process of caustic soda and hydrogen peroxide for oxygen bleaching before dyeing was replaced by very mild alkaline soda ash and a small amount of Hydrogen peroxide is used to pre-treat the fabric; at the same time, an oxygen bleaching protective agent for bamboo fiber is added to reduce damage to the bamboo fiber, avoid destroying the bamboo fiber, and make the fabric better reflect the functions of bamboo fiber.
b. Improvement of dyeing process
Due to the The reaction of fibers to reactive dyes is very different, and the dyeing synchronization and dyeing rate of the two fibers are different. Therefore, when selecting reactive dyes, after comparative experiments, there is little difference in the dyeing synchronization and dyeing rate of the two fibers. dye, so that the overall color of the final fabric is more uniform and beautiful. When choosing polyester disperse dyes, try to choose dyes that stain lightly, have good fastness, and have a relatively low dyeing temperature (125°C) to reduce the damage to bamboo fibers caused by high temperatures.
Use a large bath ratio when dyeing, increase the amount of softener in the high-temperature and low-temperature baths in the dye vat, and control the dyeing machine drum speed and dyeing pressure to make the fabric run smoothly. Reduces the friction and squeezing of fabrics in the dye vat.
1.4.8 Soft
Use water-absorbent materials that do not contain fatty acids Silicone oil makes the fabric feel fluffy, soft, smooth, and has good drape. It also ensures the moisture absorption and release function of the fabric. It can also improve the elasticity of the bamboo fiber, so that the velvet that falls down during the dyeing process can bounce back as much as possible.
1.4.9 Dehydration
This kind of fabric is in a wet state It is very easy to produce extrusion marks. These extrusion marks are difficult to eliminate in the subsequent shaping and finishing process. Therefore, dehydration should be arranged as soon as possible after the dyeing comes out of the vat, reduce the amount of dehydration at one time, and arrange the next process as soon as possible after dehydration. The production process is carried out to reduce quality problems such as creases in the fabric.
1.4.10 Finishing and drying
The test adopted A new type of whole pile drying technology. The traditional ring drying technology not only has low production efficiency, high production costs and high labor intensity for employees, but also produces severe hairiness when processing this fabric. The new technology not only completely solves the above problems, but also gives the fabric an ideal gloss effect.
1.4.11 Secondary shearing
Dried fabric Secondary shearing is required to cut off some miscellaneous hair on the velvet surface caused during the dyeing and drying process to make the velvet surface of the fabric brighter and smoother.
1.4.12 Secondary shaping
Fabric after shearing Then perform secondary shaping to make the fabric smooth and stable in shape.
The specific process is as follows:
8 boxes of shaping machine
Temperature l30℃
Vehicle speed l8 m/min
Air volume l00%
Overfeed 20 %
1.4.13 Cloth inspection and storage
2Conclusion
We have developed and innovated the fabric through a series of dyeing and finishing processes, so that the suede effect of the bamboo fiber velvet fabric has reached the previous level. The effect of polyester-cotton velvet, and the fabric is softer and brighter, giving people a silk-like feeling. The fabric maintains the unique functions of bamboo fiber varieties and is recognized by customers. </p
