The use of circular knitting machines is an important application direction of polyester drawn textured yarn (DTY), and horizontal stripes on fabric surfaces are a common problem during the use of circular knitting machines. Through communication with customers and investigation and research, we found that there are many reasons for the horizontal bars of circular knitting machines, and DTY balance time is one of the important factors. This project explores the impact of DTY balancing time on the horizontal stripes of circular knitting machines, as well as the impact of the length of balancing time on DTY performance.
1 Test Plan
Plan 4 different DTY balancing plans: ① Same raw materials, same machine, same machine Ingot position, daily fixed time sample retention balance; ② Same raw materials, same machine, same ingot position, day and night temperature difference sampling balance; ③ Different machines, same batch number, different time sampling balance; ④ Same DTY, different environments (indoor, outdoors) for a period of time.
Determine three types of yarn properties that are directly related to customer use as verification methods, and analyze the impact of different balancing times on DTY, which are: ① garter thickness; ② curl shrinkage, curl stability, Shrinkage in boiling water; ③ Bundling of filaments.
2 Test process and results
1 Same raw materials, same machine, same spindle position, sample retention at fixed time every day 1 test method
Starting from January 24, 2013, select one of the spinning positions corresponding to POY of a certain 75dtex/144f specification DTY to hang yarn separately, and process it at the 1-5# spindle positions of a fixed machine with texturing. The production team will work early every day Leave samples at spindles 1 to 5 of the doffing, and place the silk rolls in the workshop. The technical team knits socks every half month to observe the thickness changes of the white garters, and sends them to the inspection room to measure their boiling water shrinkage, curl shrinkage and curl stability, and take photos of the bundled properties of the threads at different equilibrium times for comparison.
2 Test results
The results of the garter comparison test show that the thickness of the white garter belt basically does not change within 7 days of equilibrium. After 7 days, the thickness gradually decreases compared with the standard silk garter belt. Thinning; the dyeing performance of dyed garters does not change compared with standard silk under the above equilibrium time.
From Figures 1 to 3, it can be seen that the shrinkage rate of DTY boiling water shows an overall increasing trend as the equilibrium time prolongs, but the change range is large and unstable; the curl shrinkage rate increases as the equilibrium time prolongs. It shows a decreasing trend, and the change amplitude decreases and basically stabilizes after 25 days of equilibrium; the change amplitude of the curl stability is not large, and it basically stabilizes after 25 days of equilibrium.
It can be seen from Figure 4 that the bundling properties of the silk strips began to change after 10 days of equilibrium, and the changes were obvious after 1 month.
2 Same raw materials, same machine, same spindle position, day and night temperature difference sampling balance
1 Test method
Select Silk rolls on the same machine and in the same spindle position were doffed separately under the condition of different temperature and humidity between day and night, and the garters were compared. After being placed in the same environment for equilibrium, the boiling water shrinkage and crimp shrinkage indicators were compared and tested, and the test conditions See Table 1.
2 Test results
The garter comparison test results show: No. 611 and 613 white garters dropped There is no difference in thickness or after dyeing. It can be seen from Table 2 that in the case of a small number of samples, the temperature difference between day and night has basically no effect on the physical properties of the silk roll within the range of 25°C.
It can be seen from Figure 5: there is no difference in the bundling properties of the silk strips
3 Different machines, the same batch number, and sampling balance at different times
1 Test method
The workshop currently has four machines of the same batch number: B02, C02, D01, and D02. Production machines take samples every 3 days. Comparisons were performed at the same equilibration time. 2 Test results
The results of the garter comparison test show that the garter comparison between each machine has not changed. Randomly select silk rolls from three machines for comparison. From Table 3, we can see that the physical indicators of the silk samples do not change much.
It can be seen from Figure 6 that the clustering properties of D01 and B02 are slightly better than those of D02 and C02.
4 The same DTY, different environments (indoor, outdoor) are balanced for a period of time 1 test method
The same group of DTY Take two parts of samples and store them indoors (temperature 20-25℃) and outdoors (temperature 0-10℃).Place it and observe the changes in the garters. 2 Test results
After 7 days of equilibrium under indoor environmental conditions, the thickness of the garters begins to change; under outdoor temperature, the thickness of the garters does not begin to change until about 10 days of equilibrium.
3 Test Conclusion
Judging from the above four test results, the difference in balancing time has an impact on DTY silk rolls: as the balancing time increases, the silk The bundling properties of the strips are changing, and the white garter belt becomes transparent, but it has no effect on dyeing; the shrinkage rate in boiling water increases, the curl shrinkage rate decreases, and basically stabilizes after 25 days of equilibrium; after 7 days of equilibrium at 20-25°C, The transparency of the garters begins to change, and it does not begin to change until about 10 days at 0 to 10°C, and basically stabilizes after 20 days of equilibrium. Therefore, when the temperature is low in winter, you can consider increasing the temperature in the balancing room to shorten the balancing time.
4 Suggestions
This discussion on the relationship between DTY balancing time and physical properties is based on test data from the front-line production site, which reflects the garter style and physical indicators during the DTY balancing process. , the change process of the clustering state. This performance is directly related to the customer’s use. If DTY products with the same batch number and different balancing times are mixed over a large time span, it may affect the style of the cloth, leading to problems such as horizontal stripes on the cloth. . Actively communicating with customers and using DTY raw materials based on the principle of first in, first out and no mixing at different times should reduce customer complaints and complaints, and have very positive significance in promoting mutual benefit and long-term cooperation between the upstream and downstream of chemical fiber and weaving. </p
