Effect of heat and moisture treatment on the quality of cotton yarn and knitted products

After the yarn is doubled, the yarn is subjected to moist heat finishing using water vapor, so that the yarn is initially shaped and the internal stress of the yarn is eliminated as much as possible. It is understood that most enterprises in China's cotton spinning industry do not use steaming machines to process cotton yarns. The humidity control of cotton yarns is realized through workshop storage and natural resurgence; only a few cotton spinning enterprises use traditional steaming machines to shape the strong twist yarns. . In contrast, cotton mills in North America and Europe basically use a steaming machine to process cotton yarn. The main purpose of steaming yarn is to steam and wet the cotton yarn with saturated steam to improve the strength and elongation of the cotton yarn, reduce the yarn hairiness, maintain the uniform friction coefficient of the cotton yarn, reduce the unwinding tension, and stabilize the twist of the cotton yarn. Thereby improving the quality of the cotton yarn. ? Processing cotton yarn with steaming machine can improve the strength, elongation at break and reduce hairiness of cotton yarn, which has a positive impact on the processing performance of cotton yarn. Therefore, the treatment of cotton yarn with a steaming machine can significantly improve the warp sizing rate and the loom efficiency. The cotton yarn treated by the steaming machine is evenly humidified, the yarn is not easy to yellow, and the steaming effect is uniform. After the cotton yarn is treated by saturated steam, the moisture regaining rate is increased. The reason why the application of the steaming machine in China's cotton spinning industry is not popular is because of the unfavorable factors such as uneven processing of the cotton yarn by the steaming machine and easy yellowing of the cotton yarn. With the development of shuttleless looms and knitting circular machines, higher demands are placed on yarn quality, and more and more yarn buyers are required to perform steaming treatment. The author introduces the processing technology of cotton yarn for knitting by vacuum low-temperature steaming machine, and discusses the improvement of the breaking strength, elongation at break and fracture work of knitting yarn, and the reduction of weaving breaks and cloths.

2 Steaming process and effect?
Test conditions: Steaming and knitting tests were carried out at Baosheng Garment Qingdao Co., Ltd., and dyeing was carried out at Baosheng Garment Qingdao Co., Ltd. and Jifa Huacheng Dyeing Co., Ltd. The test was completed in the Textile Laboratory of Qingdao University. The test conditions are as follows. ?
Test yarn: 18.2 tex cotton carded knitting yarn produced by Yinhe Textile Co., Ltd.
Steaming process: 65 ° C × 10 min + 75 ° C × 30 min, after cooling for 1 h, weaving on the machine. Weaving variety: plain jersey. ?
2 . 1 Physical indicators of yarn before and after steaming ?
The yarn performance test results after steaming (240h) using the above steaming process are shown in Table 1. It can be seen from Table 1 that the quality of the yarn after steaming is greatly improved. Due to the adjustment of Qingda's laboratory, after the steam was finished on February 24, 2008, the test was not carried out until March 6, 2008, and there was a data after the steaming of the test. The yarn was not broken due to improper operation. , resulting in a minimum strength of only 64cN. Despite this, the strength of the yarn is still increased by 6% and the work of breaking is increased by 18.8%. ?





2.2 Quality test of knitted products before and after steaming ?
Test conditions and results before steaming: 150.8 kg of yarn, 39.2 kg of woven fabric, 111.3 kg of yarn, and a weaving rate of 99.24%. Test conditions and results after steaming: 111.3 kg of yarn (the weight of the last steamed yarn), three pieces of woven fabric weighing 61.8 kg, the remaining yarn 49.1 kg, and the weaving rate of 99.35%. The results of knitting breaks, dropped cloths and broken holes before and after steaming are shown in Table 2. The results of the test of the break, the cloth and the hole of the 100 kg knitted fabric before and after the steaming were shown in Fig. 1 (after 240 hours of steaming). ?
As can be seen from the knitting process, the broken ends and the holes are significantly reduced. 18.2tex cotton carded cotton knit plain jersey before steaming, average 23 breaks per 100kg of rough cloth, 15.3 times of cloth loss, 7.65 holes; and 18.2tex cotton carded cotton knit plain jersey after steaming On average, it is 14.6 times per 100kg cloth break, 0 times off, and 3.24 holes. After steaming, the breakage is reduced by 36.5%, the hole is reduced by 57.65%, and the cloth is reduced by 100%. ?
2.3 Dyeing and finishing test of knitted products before and after steaming ?
The dyeing test was carried out at the instant Huacheng Dyeing Co., Ltd., and the results of the comparative test of the light blank before and after the steaming were listed in Table 3.
It can be seen from Table 3 that the dyeing yield increased by 1.26% after steaming, the lateral shrinkage and skew were reduced by 20% and 50.77%, respectively, and the straight shrinkage increased by 4.88%, which required further experimental research. ?
3 Conclusion ?
After the steaming treatment of 18.2tex cotton knit yarn by vacuum low-temperature steaming machine, the yarn and knitting quality are obviously improved, the weaving breakage is reduced, the dyeing rate is improved, and the quality and production efficiency of knitting products are effectively improved. .
The effect of breaking holes and increasing the production rate. ?
1 Analysis of factors affecting steaming ?
When steaming the yarn, the weaving gauze room is often used, and then steamed and then steamed. The method needs reasonable control in time and temperature, and the required time is long, and the shaping effect is difficult to ensure. The test is processed by a vacuum low-temperature steaming machine, which can overcome the above shortcomings and has a good shaping effect. In the process of steaming, there are certain requirements for the temperature, humidity and steaming time of the steamed yarn. The temperature should be suitable. If the temperature is too high, the yarn will be yellow, and the yarn will be too low. The greater the number of processed yarns or the higher the twist, the corresponding steaming time should be lengthened until the desired setting effect is achieved. ?