Polyester filament production process with the progress of machinery manufacturing technology and chemical processing technology, the development of a rapid, many kinds. According to the spinning speed can be divided into conventional spinning process, medium-speed spinning process and high-speed spinning process. According to the polyester raw material can be divided into melt direct spinning and chip spinning. Direct spinning method is the melt in the polymerization kettle directly sent to the spinner for spinning; slice spinning method is the polycondensation process of polyester melt by casting, cutting and drying before spinning, the use of screw extruder will be melted into a melt and then spinning slice. According to the process flow there are three-step method, two-step method and one-step method.
1. Conventional spinning process
Conventional spinning, also known as low-speed spinning, is the earliest industrialized production of a process route. Spinning winding stretching twisting a false twist deformation (UDY-DY-TY) of the three-step process route. Spinning speed of 100O ~ 1500m/min, stretching and twisting speed of 600 ~ 1100m/min, false-twist deformation speed of 120 ~ 160m/min, post-processing stretch times of 3.5 ~ 4.2 times (false-twist deformation before processing). It can spin 33～167dtex filament.
Conventional spinning can produce both stretched and deformed silk, which is characterized by mature technology, stable equipment operation, easy to master the technology, better product quality and good dyeing uniformity. Deformation of silk M (M silk for the measured deformation of silk and standard deformation of color absorption difference within half a level of normal dyeing silk) up to 96%. But the process is long, low production efficiency.
2. Medium-speed spinning process
Medium-speed spinning is a two-step process. Spinning speed of 1800 ~ 2500m/min, the production of semi-pre-orientation silk (MOY). Medium-speed spinning has two process routes.
1,MOY-DY process
This process adopts medium speed spinning and low speed stretching. Spinning speed of 1800 ~ 2500m/min, stretching twisting speed of 800 ~ 1200m/min, can be spun 33 ~ 167dtex stretching silk, commonly 75dtex and 50dtex. its productivity is lower than the high-speed spinning, product quality is worse than conventional spinning.
2,MOY-DTY process
This process adopts medium-speed spinning, high-speed stretching deformation, MOY remaining stretch multiples of 2.1 ~ 2.4 times, stretching deformation speed of 400 ~ 500m/min, can be spun 55 ~ 88dtex deformation of the silk, more than 110dtex need to merge two strips of silk into a tube. The productivity and product quality of this process is not as good as POY-DTY process.
3.High speed spinning process
High-speed spinning has a spinning speed of 3000 to 3600 m/min to produce pre-oriented yarn (POY). There are three process routes for high-speed spinning.
1,POY-DTY process
This process adopts high-speed spinning and high-speed stretching and deformation, which is a typical two-step process route, and it is the process route that produces the most deformed silk at present.
The post-processing speed of POY is usually 400-800m/min, and it can spin 50-167dtex deformed yarn (DTY). It is characterized by short process, high production efficiency and low investment in infrastructure. POY can be stored for a long time and transported over long distances; DTY is of excellent quality.
2,POY-TY process
This process adopts high-speed spinning, low-speed false-twisting deformation (rotor-type false-twisting method), can be spun 111 to 167dtex deformed silk. This process route in the technical and economic unreasonable.
3,POY-DY process
This process adopts high-speed spinning and low-speed stretch twisting, and can spin stretch yarns of 55 to 110 dtex. The stretch ratio is 1.3 to 1.7 times, using the general stretch twisting machine. The performance of DY produced by this process is not as good as that of UDY.
4. Spinning and stretching one-step process
This process adopts two processes of spinning and stretching in one spinning and stretching combined machine, which is a one-step process route. There are two kinds of production process, one is the spinning speed of 900 ~ 1500m/min, stretching speed of 3200 ~ 4000m/min, stretch ratio of 3.5 times, can be spun 55 ~ 165dtex stretching filament; the other kind of spinning speed of 2600 ~ 3500m/min, stretching speed of 5100 ~ 5500m/min. The filament produced by this process called FDY.
5.Other Spinning Processes
Polyester filament production process in addition to the above, there are highly oriented yarn (HOY) production process and high crystalline yarn (HCY) production process.
High Orientation Yarn (HOY) is also known as fully oriented yarn. This process uses a one-step ultra-high-speed spinning, spinning winding speed of 5500 ~ 6000 m / min. Due to a substantial increase in the nozzle stretching, fiber orientation greatly improved, but the crystalline particles, amorphous area of low orientation, fiber dyeing performance is better, but the elongation is too large (about 40%), even if the winding speed to 7000 ~ 8000 m / min, the elongation is still Even if the winding speed is increased to 7000-8000m/min, the elongation is still not able to meet the general requirements, and is still in the experimental production stage.
Highly crystallized yarn (HCY) is produced by one-step method of high-speed spinning and heat pipe stretching. In the ordinary high-speed spinning process, in the fiber solidification cluster on the oil before adding a section of the heat pipe, by the hot air will be heated to the filament above the glass transition temperature (below the softening point), so that the solidification of the filament in the coiling traction under the action of further stretching.
Production characteristics of polyester filament yarn
Spinning, stretching and deformation processing of polyester filament yarns are carried out on individual spindles. When the later process is processing the ingot of the former process, although some shortcomings can be improved or compensated by adjusting the process of the later process, some shortcomings not only can't be compensated, but also may be magnified, such as the difference between the ingots. Therefore, reducing the difference between the spindle position is the key to ensure the quality of filament. With the development of spinning technology, polyester filament production has the following production characteristics.
1,High production speed
With the development of filament production technology, spinning speed is getting higher and higher, and now most of them have reached about 3500m/min. Spinning speed increases, the process, equipment, operation and so on put forward higher requirements.
2,Large capacity of roll loading
The net weight of coiled silk cylinder is increased from 3~4kg to 15kg, and that of deformed silk cylinder is increased from 1~2kg to 5kg. the increase of coiling capacity puts forward new requirements on the coiling mechanism, uniformity of the quality of the cylinder silk, and the packing and transportation of the cylinder.
3,High raw material quality requirements
The quality of polyester raw material is closely related to the spinnability of filament and product quality. In addition to the requirements of the quality indicators of the slice - characteristic viscosity, softening point, diethylene glycol content, carboxyl content, ash and cohesive particles qualified, at the same time, the appearance of the shape of the slice, the presence or absence of carbon black particles, the distribution of the relative molecular mass, the moisture content of the spinning is also a great influence on the spinning properties, especially the moisture content of the high-speed spinning of silk has a greater impact on the requirements of the slice of the ancient water rate of not more than 30 ~ 50 ppm. The water content of the slices should not be more than 30~50ppm, and the quality of the raw materials should reach the quality index, be uniform and consistent, and the quality of the slices should be stable and consistent from batch to batch.
4,Strict process control
Filament production requires very strict process parameters. For example, the melt temperature up and down fluctuations of no more than ± 1 ℃, the side of the wind blowing wind speed difference of no more than 0.1m / s, the spinneret requires daily shovel plate surface. Public works (such as water, gas, steam, electricity) also have high requirements.
5. Requirement of total quality management
Filament production is a multi-spindle, multi-machine assembly line operation, frequent operation, labor-intensive, good or bad management work and the relationship between the quality of filament is very close. In order to ensure product quality, it is necessary to implement comprehensive quality management and establish quality assurance system.
6, the requirements of good inspection, packaging, storage and transportation work
In order to ensure the quality of filament, each batch of raw materials are required to test its physical indicators, the winding tube to be tested one by one the appearance of defects, the finished silk dyeing properties to be sampling or all the test, packaging process, different specifications can not be mixed bags. In addition, we should pay attention to the storage and transportation work, storage can not be sunshine and night dew, stacking boxes can not be too high, loading and unloading requirements of the light put, transport to avoid bumps as far as possible.