Development of the hottest cotton silk blended fin

2022-08-22
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The development of cotton silk blended fine yarn

this paper introduces the experience of successfully producing high-grade cotton silk blended fine yarn on the traditional cotton spinning equipment through the setting of process flow, the modification of key equipment components and the optimization of process parameters, especially the pretreatment of silk raw materials

1 preface

with the continuous improvement of living standards, high-grade new textiles are favored by people. In recent years, our factory has continuously developed modal, Lyocell, Tencel, PTT pure and blended yarn, as well as satin, silk and other products in the process of developing UD belt technology. Recently, we have successfully developed and mass produced CJ/silk (80/20) 9.7 tex blended yarn

2 raw cotton is selected as raw material: long staple cotton 60%, average length 34 mm, average grade 1.4, short staple rate 7.94%, maturity 80

silk: mulberry silk cut into packages, with fineness of 1.17dtex and main body length of 45mm

3 selection of technological process

there are two technological processes to choose from. The first is to mix and pack 50% combed cotton sliver and 50% spun silk, and the raw sliver is pre combined and mixed with combed sliver in a certain proportion on the drawing frame; The second kind is that the raw cotton and silk are respectively frayed and boxed, and they are separated into strips by the carding machine. The combed strips are mixed with the pre merged silk strips in proportion on the drawing frame. After a small amount of trial spinning, the spinning quality of the two processes is compared. The second scheme is obviously better than the first one. The key is that the silk can pass smoothly on the carding machine. Energy efficiency, environmental protection and product quality must be comprehensively considered separately

3.1 spun silk sliver making

a002 disc cotton grabber-a035as mixed cotton opener-fa106a porcupine cotton opener (more suitable for high-energy density battery carding) -a092as cotton feeder-a076c coiler-toyoda carding machine-a272f drawing frame (pre purified and combined)

3.2 combing sliver sliver making

a002 disc grabber-a035as mixed slitter-a034 six roller slitter-fa106 porcupine slitter-a092ast oscillating cotton focus on the development of organic chemical raw materials and new chemical material box feeder-a076c single beater coiler-toyoda carding machine-fa302 pre blending-a191 slitter-a201 D comber

3.3 drawing mixing and spinning

a272f drawing frame (combed cotton and spun silk pre drawing three-way mixing) -a454 roving frame FA503 spinning frame 1332 winding machine

4 technological measures

4.1 pretreatment of spun silk

the specific resistance of spun silk is high. If no measures are taken, it is very easy to generate electrostatic accumulation in the production process, which is not only difficult to operate, but also has numerous yarn defects, serious deterioration of quality, and extremely poor spinnability. Before spinning, we must pretreat the raw materials. The silk bag and flower jar are used for loosening. While loosening, the antistatic agent and 60 ℃ warm water 1:10 mixed solution are sprayed, and then packed and left for 24 hours to ensure full penetration. The moisture content of the silk is controlled at about 16%

4.2 process parameters and measures of each process

4.2.1 the silk with high moisture regain has a certain impact on opening and loosening, and because the fineness of the silk is fine, severe blow will damage the fiber, so it is appropriate to give priority to opening and combing instead of beating. Reduce the distance between the cotton pressing curtain and the corner nail inclined curtain to 40mm on the a035as cotton blending machine, and appropriately speed up the corner nail curtain to increase the loosening effect; In order to prevent rolling, slow down the speed of the horizontal curtain appropriately; Silk contains very little impurities, so the fan speed can be appropriately increased, so as to ensure that the cotton conveying pipeline is unblocked, reduce flower return and increase the recovery of silk. Properly reducing the speed of each beater can reduce the damage to the spun silk. At the same time, combing can replace beating, and full loosening can ensure good roll forming. The beater speed of a035as mixed cotton opener is 583 R/min, the beater speed of fa106a porcupine (carding needle) is 510 R/min, the comprehensive beater speed is 812 R/min, the fan speed is 1240 R/min, the cotton roll roller speed is 12 R/min, the yarn weight is 390g/m, the yarn length is 27m, and the weight unevenness is controlled at about 1.1%

4.2.2 when the carding carding machine is running, there are usually two situations: the first is that the fibers are easy to wind around the cylinder, and the second is that the cotton adsorbs the metal cotton guide roller. The former is because the improper selection of carding elements makes the fibers unable to transfer smoothly, or the fiber oil is added too much, and the adhesion is increased. The latter reason is that the fiber is adsorbed on the surface of the metal roller due to electrostatic effect

the pretreated spun silk will not be adsorbed on the cotton guide roller, but the adsorption must be observed in time in production practice in order to correctly and evenly pretreat the spun silk. The optimization of carding elements and process parameters is as follows

carding element: cylinder clothing 2810 × 1665, pricking roller saw blade 5805 × 07011. The doffer needle cloth is 42ac-4b, and the cover plate needle cloth is h28

main process parameters: take-up roller cylinder spacing 0.18mm, cylinder doffer spacing 0.1mm, cover plate spacing 0.2, 0.18, 0.18, 0.2 mm

with the above carding elements and process parameters, the spun silk is not wrapped around the cylinder, and the cotton is smoothly made

during the operation of the carding machine, we found that there was often strip-shaped thick cotton on the silk cotton, which seriously affected the cotton quality. After careful observation, it was found that the silk loose fibers were very easy to accumulate at the inlet of the large leakage bottom. We cut off two leakage grids (about 35mm) from the large leakage bottom, and appropriately enlarge the distance between the inlet of the leakage bottom. The process parameters are: the inlet of small leakage bottom is 7.9MM, the spacing of the fourth point is 0.79mm, the spacing of the upper opening of the front upper cover plate is 0.55mm, and the spacing of the lower opening of the front lower cover plate is 0.79mm

after operation observation, the accumulation of loose fibers was eliminated, and the spun silk cotton was normal

in order to ensure the normal operation of the carding machine, a vapor mist humidifier is also equipped to control the relative humidity in special areas at 70% - 75%

after taking the above measures, the spun silk can be smoothly sliced on the carding machine table. The carding sliver weight is 19g/5m, the spun silk neps are 35 grains/g, and the raw spun silk sliver Sabouraud stem is 15.6%

4.2.3 draw Silk Green sliver adopts pre drawing. In order to reduce the stretching force and improve the fiber straightness, 5 pieces of pre drawing are combined and a large rear area drafting multiple is adopted. In order to fully mix silk and cotton, we adopt three-way drawing. Because the main length of cotton and silk is different, and considering that the proportion of cotton accounts for 80%, we should take a cautious attitude towards the selection of roller spacing. On the basis of ensuring the quality of sliver, the spacing should be smaller. The drafting of the rear area of each channel is considered from the straightening of the reinforcing fiber, and the corresponding configuration is also made. See Table 1 for specific process parameters

after mixing for three times, the CV value of evenness of sliver quality level is 0.81%, and the CV value of Uster dry sliver is 3.2%

4.2.4 the length distribution of roving spun silk is mm, and the dispersion is large. In the roving process, it is necessary to strengthen the control of floating fibers, and the center distance of rollers should be small; Under the condition of ensuring that the spinning yarn does not come out of the hard end, the control of the roving twist coefficient is too large, which is beneficial to improve the yarn evenness, especially to reduce the details. At the same time, the tension difference between the large and small yarns is strictly controlled within 0.6%, which will improve the yarn weight unevenness to a certain extent

specific process parameters: roving ration 3g/10m, drafting multiple 8.33, rear drafting 1.1 times, roving twist factor 97. Roller center distance is 52.5 mm x 56.5 mm, leather ring jaw is 4.5 mm, front roller speed is about 160 R/min, roving quality level weight unevenness CV value is 1.03%, roving Uster Evenness CV value is 4.52%

4.2.5 spinning in order to improve the quality level, the speed of the front roller of spinning should be appropriately slowed down, and in order to reduce details, a small back draft should be adopted; The use of narrow steel collar is of great benefit to the improvement of yarn quality and the reduction of hairiness; In order to reduce the details caused by the unexpected drafting of roving sliver by the sluggish lifting spindle, we have sorted out the lifting spindle and eliminated the lifting spindle with inflexible rotation

process parameters: drafting multiple of the back area is 1.1, spinning twist coefficient is 336, and the center distance of spinning rollers is 43.5 mm × 63.5 mm, the steel ring adopts PG1/2, 38 diameter narrow edge steel ring, steel ring rss12/0, leather ring pin jaw 3.5 mm, and the front roller speed is about 160 R/min

spinning quality level: yarn weight unevenness CV value is 1.8%, single yarn breaking strength is 18.3cn/tex, single strength CV value is 8.1%, spinning Uster Evenness CV value is 14.3%, details are 19.5 pieces/km, coarse knots are 99 pieces/km, neps are 16 pieces/km, 100000 meter yarn defects (Level 9) are 1.5 pieces (a 1286 pieces, B 14 pieces, H 167 pieces, I 10 pieces), spinning blackboard neps are 32 pieces/g, and the bobbin hairiness is 28 pieces/m above 3mm

5 conclusion

from the perspective of yarn quality, high single yarn strength, less details, less hairiness and better evenness are the greatest success of this spinning production practice, which has also been highly praised by users

our main experience is: we should pay attention to the pretreatment of silk, and we must maintain consistency and uniformity; The adoption of several technical measures in the carding process is the key to the improvement of the state of spun silk and cotton. The separate sliver of spun silk on the carding machine has laid the foundation for the mixing with various proportions of cotton fiber; Light weight, slow speed and small spacing are the keys to improve yarn quality

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