To produce bamboo fiber, we need to build a viscose production line! Because bamboo fiber is viscose!
To produce towels, we need to build a spinning and weaving factory, produce bamboo fiber yarn to weave towels, and do simple washing!
To produce clothing, you need to build a clothing factory!
However, countries restrict the launch of viscose production lines, mainly due to pollution and large amounts of water!
Moreover, building a viscose production plant requires at least nearly 100 million yuan, and building a small-scale textile factory requires at least nearly 100 million yuan of capital investment. A few million is enough for a small clothing factory. Taking the analysis of the carding process in the bamboo fiber vortex spinning process as an example. In the production of bamboo fiber yarn produced by vortex spinning, the quality of the carded sliver has a significant impact on the structure and performance of the vortex yarn. Aiming at bamboo fiber performance and vortex spinning process requirements. The carding clothing configuration, licker-in speed, distance between licker-in roller and cotton feed plate, cylinder to doffer speed ratio and relative humidity were analyzed. By improving the fiber uniformity in the card sliver and reducing hooks and neps, the quality of bamboo fiber vortex spinning can be improved.
0Foreword
Bamboo fiber is a new regenerated cellulose fiber made by dissolving and spinning bamboo pulp. It has natural antibacterial properties, good air permeability, unique resilience, It has excellent properties such as instant water absorption, anti-shrinkage, strong longitudinal and transverse strength, and combines the advantages of natural fibers and man-made fibers. It is an environmentally friendly fiber. We used vortex spinning to spin bamboo fiber yarn. Based on the performance characteristics of bamboo fiber and the requirements of the vortex spinning process, we conducted an experimental analysis on the impact of feeding fiber strips on the quality of vortex spinning. We found that a reasonable selection of the carding process is the best way to improve the quality of the vortex spinning yarn. Vortex spinning is the key to quality and yield.
The mechanism of vortex spinning is that the fiber strips are drawn to form fiber bundles. The fiber bundles are twisted and expanded at the end under the control of stable eddy current in the nozzle, and then rotated by the twisting action of the hollow spindle. , completing the twisting effect of the outer wrapping fibers and the yarn core fibers, and the yarn has unique internal and external structural characteristics. The external structure is similar to ring spinning, and the external wrapped fibers are in a spiral shape, forming twist together with the untwisted yarn core, compared to true twisted yarn. There are relatively few wrapping fibers, and some are stretched and wrapped. The arrangement of the internal yarn core fibers directly affects the strength of the yarn. For example, if the fiber distribution is well oriented, the number of fibers bearing stress per unit section is large, the probability of weak loops and details in the yarn strength is small, and the breaking strength of the yarn is increased. If there are many fiber hooks and neps in the feed during vortex spinning, the yarn core fiber will have poor orientation and will easily produce strong weak loops and details. High lint content will also cause fiber loss during vortex spinning production, causing the vortex yarn to break. Intensity decreases. It can be seen that the fiber uniformity, hooks and neps in the feeding fiber strips directly affect the yarn structure and performance of the bamboo fiber vortex yarn, while the quality of the fiber strips mainly depends on the carding and combing of the fibers during the carding process. transfer.
1 Raw material properties and spinning process
1.1 Bamboo fiber properties
Bamboo fiber fineness 1.67 dtex, length 38 mm, moisture regain 10.5%, breaking strength 4.35 cN/dtex, and elongation at break 20.3%.
1.2 Process flow
1.3 Quantification of each process
The bamboo fiber vortex yarn number is 14.7 tex, and the quantification of each spinning process is : Opening roll is 395g/m, carding sliver is 18.84 g/5m, first and second union is 17.85 g/5m, and second union is 16.6 g/5m.
2 The influence of carding process on the quality of bamboo fiber vortex yarn
Combining the performance of bamboo fiber and the process characteristics of vortex spinning, focusing on strengthening the carding and transfer effects during the carding process, Analyze the influence of carding process on the yarn structure and performance of bamboo fiber vortex yarn in terms of reducing the number of fiber hooks and neps, avoiding fiber damage, and controlling short lint.
2.1 Specifications of card clothing
The specifications and parameters of the selected card clothing must meet the requirements of strengthening carding and transfer, so that the carding and transfer can obtain the best configuration during the carding process. and optimal grooming quality.
Considering the fineness, long length, and low impurity content of bamboo fiber, there is a lot of static electricity during the carding process, and it is easy to wrap around the card clothing. Therefore, the card clothing used should be such that the card clothing of the carding machine is less stuffed, the fiber load is light, and the fiber transfer rate is high. , the card sliver has less knots, the cotton net has high definition, the fiber carding is good, and the fiber damage is less. The main specifications and parameters of the card clothing selected for spinning bamboo fiber vortex yarn are shown in Table 1.
Licker-in card clothing: Use high-quality hacksaw blades with good tooth tip sharpness, wear resistance, smoothness, and flatness to avoid wear and damage to fibers by inverted teeth. Appropriately increase the number of tooth tips and base per unit area. The thickness is narrow to improve carding and reduce the burden of carding in the cylinder and flat areas.
Cylinder card clothing: It adopts short teeth and shallow teeth to keep the fiber at the tooth tip during the carding process, increasing the contact length and number of teeth between the cylinder card clothing and the other needle surface, which is beneficial to the fiber Combing and transfer improve the combing effect and even mixing effect. The card clothing has a light load and a high transfer rate, which is beneficial to reducing neps. The use of thin and dense teeth increases the fiber holding and carding capabilities. The thinning of the base thickness increases the transverse density of the card clothing and increases the transverse and longitudinal tooth density ratio, which is beneficial to carding the fiber bundles into single pieces. Fiber, it is beneficial to reduce neps, improve cotton web uniformity, cotton web structure and fiber straightness, improve yarn quality and reduce tooth tip wear. In order to enhance the transfer and release performance during the bamboo fiber carding process and avoid the fibers from wrapping around the card clothing and sharply increasing neps, the working angle can be controlled to be larger.
Doffer card clothing: The main function of doffer card clothing is to condense fibers, fully transfer the single fibers that have been carded from the cylinder in time, and condense them into cotton nets. The doffer card clothing should have sufficient Grasp and hold ability. Therefore, in order to ensure timely, sufficient, and normal transfer of fibers and solve the problem of smooth guidance of high-speed airflow, tooth height, large tooth gap capacity, small working angle, and arc-shaped tooth tips can be used to improve the transfer capacity. The depth of the teeth of the doffer card clothing is increased, and the capacity between the teeth is increased. The gripping force of the doffer card clothing is large, which is beneficial to accommodate more fibers, and is beneficial to the guidance and downward release of airflow in the cylinder and doffer action areas. The use of arc-shaped variable-angle tooth tips can greatly improve the stripping and transfer performance of doffer card clothing. Reducing the tooth tip angle is beneficial to puncturing the fiber layer and condensing the cotton web. It also significantly reduces neps and improves the quality of the cotton web. .
Flat card clothing: The cylinder and flat card clothing are the main carding areas of the carding machine. The carding function is completed simultaneously by the cylinder card clothing and the flat card clothing. The flat card clothing adopts transverse needle points. The arc-shaped curve arrangement with small spacing and gradually thinning longitudinal needle root spacing is conducive to fiber release and transfer. The card clothing load is light and the cover plate flowers are less. It also ensures sufficient carding ability and reduces neps.
2.2 Lick-in noil control
Due to the good length and uniformity of bamboo fiber and less impurities, in order to reduce the carding burden in the cylinder and cover area, it can be strengthened The opening and carding function of the licker-in is to improve the carding degree of the fiber transferred to the cylinder. Therefore, the speed of the licker-in can be appropriately increased (controlled at about 800 r/min). At the same time, the speed ratio between the cylinder and the lick-in roller is also increased, which is beneficial to the transfer of fibers from the lick-in roller to the cylinder, thereby reducing neps and improving the evenness of the yarn. The influence of licker-in speed on bamboo fiber sliver dryness is shown in Figure 1.
Figure 2 shows the effect of the tightest distance between the cotton feed plate and the lick-in roller on the breaking strength of bamboo fiber vortex yarn. The speed of the licker-in roller is high, and the licker-in roller violently opens and combs the fibers held by the cotton feed roller and the cotton feed plate. Improper handling can easily cause fiber damage. In order to avoid excessive damage to the fibers and improve the yarn strength, an arc-shaped cotton feeding plate can be used. The closest distance between the cotton feeding plate and the lick-in roller should be appropriately enlarged. At the same time, waste control should be strengthened, the position of the dust removal knife should be appropriately raised and the installation angle of the dust removal knife should be increased, and the air suction volume should be increased without interfering with the air flow of the licker-in roller air cover. In particular, the suction of the rear belly should be strengthened to eliminate dust removal. Knife and small leak bottom hanging flowers to reduce fiber loss. You can also use a meshless panel leak bottom and reduce the inlet distance. This can prevent a large amount of airflow from entering the leak bottom and cause excessive air pressure, and reduce the accumulation of dust inside the small leak bottom.
2.3 Linear speed ratio between cylinder and doffer
Since the vortex yarn has the internal and external structural characteristics of a spiral outer wrapped fiber and an inner untwisted yarn core, the inner yarn core The arrangement of fibers directly affects the strength of the yarn. The main factors that affect the strength of the yarn are details and strong weak loops. There are many fiber hooks and neps, and the probability of strong weak loops and details is high, resulting in a decrease in the breaking strength of the yarn. It can be seen that not only the carding process should be emphasized to fully card the fibers, but also the transfer effect of the doffer should be paid attention to, reducing the number of fiber hooks and neps, and ensuring the quality of bamboo fiber vortex yarn.
Figure 3 shows the effect of cylinder to doffer line speed ratio (Vc/Vd) on the breaking strength of bamboo fiber vortex yarn. The bamboo fiber selected is thin and long, with low rigidity, low bending strength and good adsorption. It is easy to generate static electricity during the carding process, which will affect fiber transfer. The study found that as the linear speed ratio between cylinder and doffer decreases, the number of fiber hooks in the raw sliver increases significantly, and the yarn dryness and single strength decrease significantly. If the fibers carded in the working area of ??the cylinder cover plate cannot be well transferred by the doffer, they will return to the space between the cylinder and the cover plate to form repeated carding. Excessive repeated carding will increase the amount of short lint and create new fibers. Neps, and affect fiber straightness. According to the performance characteristics of bamboo fiber, while appropriately reducing the doffer speed, reduce the distance between the cylinder and the doffer, appropriately increase the line speed ratio between the cylinder and the doffer, enhance the fiber transfer ability from the cylinder to the doffer, and achieve fast transfer , improve the fiber straightness when the fiber is transferred from the cylinder to the doffer, reduce the occurrence of fiber hooks, enhance the carding degree, improve the elimination of knots and short lint, and improve the quality of the sliver.
2.4 Control of relative humidity
Figure 4 shows the effect of relative humidity on the dryness of bamboo fiber slivers. Because the moisture regain of bamboo fiber is high, but the bamboo fiber is thin and long, there is static electricity during the carding process. The fiber easily adheres to the card clothing, making it difficult to peel off the fiber web. The relative humidity has a very obvious impact on the quality of bamboo fiber yarn and cannot be ignored. . The relative humidity is too high, and the unwinding adhesive layer affects the uniformity of the feeding fibers, increases the carding burden, and the fiber web transfer is poor, resulting in an increase in neps and impurities, making it difficult to peel off the fiber web, and prone to sagging, holes and even breakage; relatively If the humidity is too low, the electrostatic effect will be enhanced, and the fibers will adhere to the card clothing, affecting the transfer of the doffer, which will easily cause the fiber web to float and break, causing the sliver to become fluffy and uneven.
According to bamboo fiber spinning practice, the relative humidity is controlled between 65% and 70% to reduce the adhesion of card clothing and winding of pressure rollers and ensure the quality of the sliver. Before spinning, you can spray an appropriate amount of anti-static agent and anti-slip agent on the fiber to increase the softness and cohesion of the fiber and make it meet the requirements of spinning.
3 Conclusion
(1) High-quality bamboo fiber vortex yarn can be spun using vortex spinning technology. According to the performance characteristics of bamboo fiber and the requirements of vortex spinning process, the choice should be reasonable. The carding process is the key to improving the quality of vortex spinning.
(2) Select card clothing that strengthens carding and transfer and reduces neps and fiber damage to improve the carding and transfer capabilities of the card clothing so that the bamboo fiber can obtain the best carding quality during the carding process. .
(3) Appropriately increase the speed of the licker-in, enhance the opening and carding effect of the licker-in, and at the same time improve the transfer ability of the licker-in fiber to the cylinder, so as to reduce neps and improve the evenness of the yarn.
(4) Appropriately increase the speed ratio between the cylinder and the doffer to achieve fast transfer, significantly improve the fiber straightness of the card sliver, reduce the occurrence of fiber hooks, and improve the quality of bamboo fiber vortex spinning.
(5) The relative humidity in the workshop has a significant impact on the quality of bamboo fiber spinning. Too high or too low relative humidity will obviously affect the quality of the raw sliver. Therefore, it is necessary to strengthen the control of the relative humidity of the environment during the production process. control.