In recent years, far-infrared fibers and their fabrics have become popular in the domestic market, and various researches have ignited the upsurge of research and development of far-infrared fibers and their fabrics, which are mainly related to the special health care functions of far-infrared textiles, but in the case of far-infrared polypropylene, Based on short fiber varieties, the research on spinning and post-processing of high-speed spinning far-infrared polypropylene filaments, especially fine-denier far-infrared polypropylene filaments with a monofilament linear density of about 1 dtex has not been reported, in order to fill this gap. The National Engineering Research Center for Synthetic Fibers conducted a research project in 1999. In 2000, the project passed the identification of new products in Shanghai. At present, it has the ability to mass production. The functional health-care textiles made by 82/72fDTY are put on the market. After being welcomed by the majority of users, the study selected high-efficiency far-infrared masterbatch and cooling masterbatch. The method of full granulation was used to first obtain far-infrared PP, and then focus on the spinning process and deformation process. Propylene Y2600, Shanghai Petrochemical Co., Ltd. Plastics Division; far infrared masterbatch 1; cooling masterbatch A; oil agent, Germany Henkel company students A-2 type of special polypropylene spinning oil 1.2 pelletizing equipment and process GH-10 high-speed mixer, Beijing Plastic Machinery Plant; SH-35 type twin-screw kneading extruder, Shanghai Chemical Machinery four plants.
Granulation temperature 190~210C, the process flow is as follows: polypropylene far infrared masterbatch (20%)>mixer> twin-screw extruder cooling masterbatch (3%) - let one> pelletizer 1> dry one> Far-infrared PP 13 spinning deformation equipment wire machine, SW46SSD winding head; spinneret: 0. 72f, spinning speed company FK6V-900MF216 ingot texturing machine 14 test crystallization performance Japanese science 3134 X-ray diffractometer, Cu target , working voltage 35kV, propagation speed Cs in 20, sample sound velocity orientation factor is obtained according to the formula fs=1-(G/Cs)2, Cu takes 1.45km/s birefringence Japan Nikon polarized microscope fineness German Textechno fiber test Changyi strong stretch Germany Textechno company Stimamat type automatic stretching instrument crimping Germany Textechno company automatic crimping machine 2 results and discussion 2.1 spinning temperature on the fiber structure performance from the known, add cooling masterbatch far infrared PP Although the viscous flow activation energy is slightly decreased, it is still high, and the viscous flow activation energy is one of the indicators of the sensitivity of the melt viscosity to temperature. The higher the viscous flow activation energy, the narrower the control range of the spinning temperature. , especially spinning fine denier polypropylene, even tiny temperature waves It is also easy to affect the performance of the fiber and the stability of the spinning. Therefore, when the far-infrared PP is spun at high speed, the spinning temperature should be strictly controlled.
Physical property data obtained by spinning far-infrared polypropylene at 500 m/min. It can be seen from Table 1 that as the spinning temperature increases, the intensity of the far-infrared PP-POY decreases, the elongation increases, the unevenness of the strip first decreases and then rises, and the birefringence value also decreases slightly. The spinning principle is basically the same. Because 250C is close to the boiling temperature of the biphenyldiphenyl ether, the temperature control system has poor stability, and there are many floating filaments during spinning, and the spinnability is poor. The temperature above 265C is likely to cause thermal degradation, resulting in a decrease in strength, and the phenomenon of floating monofilament also gradually increases with the increase of spinning temperature. Therefore, the general spinning temperature is controlled at about 258C, and the spinning temperature of Table 1 is good for POY. Spinnability. Structural properties affect the dry U value, 厶nX spinnability is better, better than the difference 2.2 spinning speed on the performance of far-infrared fiber structure Table 2 lists the spinning temperature of 260C spinning far-infrared polypropylene spinning The impact of speed on its structural performance.
Table 2 Effect of spinning speed on fiber structure performance V/Line density/head stretch is large, the axial velocity gradient on the spinning process is large, the spinning tension is increased, resulting in fiber orientation, and the orientation further induces crystallization, resulting in mechanical properties The spinning speed is increased and monotonous (within the test speed range), which is consistent with the conventional melt spinning principle. Polypropylene has various crystal forms such as aå©, YS and quasi-hexagon, during the forming process. Different crystal structures are often obtained with the change of processing conditions. The X-ray diffraction patterns of far-infrared POY with different spinning speeds can be seen from Table 2. As the spinning speed increases, the far-infrared fiber strength and elongation Decrease, crystallinity addition, birefringence plus orientation plus. This is because, as the spinning knows, with the increase of the spinning speed, the crystal form of the fiber is gradually changed while the crystallinity is increased, the content of the quasi-hexagonal crystal form is gradually decreased, and the content of the a crystal form is gradually increased. At a spinning speed of 2700 m/min, the crystal form completely changed to the T crystal form. Although the spinning speed is higher at 2700m/min, the spinning tension is larger and the cake is difficult to unwind. Further post-processing studies show that: a crystal form is relatively stable, which is not conducive to post-processing, and the final product obtained. The mechanical properties are poor. Quasi-hexagonal crystal form is a relatively complex and incomplete crystal form, easy to process, and gradually converted into a more stable a crystal form during processing. See to ensure that the far-infrared PP-POY crystal form is quasi-hexagonal ( Mainly), therefore it is recommended that the spinning speed should not exceed 2500m/min. 2.3 Effect of cooling forming conditions on fiber structure properties When spinning polypropylene high-speed spinning, even if the cooling masterbatch is added, the spinning temperature is still higher than the melting point of 90C or even 10C. In the above, in the cooling forming stage, more heat is released than the polyester. If it is difficult to smoothly form the molding under the cooling condition of the polyester spinning, the length of the spinning tunnel during the forming of the polypropylene is generally greater than that of the polyester but due to the spinning used. The wire device is mainly for polyester varieties, and it is difficult to adapt to the needs of high-speed spinning of polypropylene from the length of the spinning nozzle. Practice has proved that it is feasible to adopt a method to appropriately reduce the side blowing temperature. The test results are shown in Table 3. Table 3: Effect of blowing temperature on fiber structure performance 4 Influence of oil position on fiber structure performance Far-infrared PP high-speed spinning When the spinning tension is higher than that of polyester, and the excessive spinning tension is not conducive to the fiber package forming, the yarn is generally bundled in advance to reduce the spinning tension and facilitate the winding of the fiber. To improve the quality of the silk cake, but the position of the bundle should not be too high, otherwise the fiber is not fully solidified, and it is easy to produce undesirable phenomena such as silk and wool, which leads to the dryness of the fiber strip. The results of the research on the selection of different oiling positions for spinning are shown in Table 5. Table 5 Effect of the oiling position of the bundle on the fiber structure properties. Dry U value, % bundle oiling position / mm dry U value, spinning tension / Note: Bunching The oiling position is the distance from the bundling point to the spinneret.
It is known from Table 3 that as the side blowing temperature is increased from 15C to 21C, the extension of the far-infrared pY and the birefringence decrease, which is related to the downward movement of the fiber freezing point and the decrease of the spinning tension. If the side blowing temperature is lower than 15C, the fiber If the cooling rate is too fast, the tensile stress of the nozzle will be higher, the filaments will be easily produced and the strips will be higher. On the contrary, if the temperature is higher than 21C, the fiber cooling effect is not good, and it is possible to join the filaments, which may lead to the rise of the strips. Generally, the side blowing temperature is about 18C. It is better to reduce the side blowing temperature than the large speed. However, for the fiber performance and spinning stability, the side blowing speed is too large, which not only affects the fiber. The strips are also easy to cause the phenomenon of floating filaments on the premise of the selected side blowing temperature. The effects of wind speed on the structural properties of the fibers are studied in the experiment. The results are shown in Table 4. Table 4: Effect of wind speed on fiber structure properties The dry U value, as shown in Table 4, the side blowing speed is too high or too low, which leads to the high dry value of the fiber strip, the side blowing speed is about 0.4 m / s, and the far infrared PP-POY strip is the smallest. Therefore, The side blowing speed should be about 4 m/s. It can be seen from Table 5 that as the oil position of the bundle moves downward, the fiber strength increases slightly, the elongation decreases, the spinning tension is gradually increased, and the strip dry value is the smallest at 920 mm. Considering the above factors, the cluster is When the oil position is about 920mm from the spinneret, the final éš¹25 stretch false twist deformation process selects the influence factors of the deformation false twist process. There are two hot box temperatures, D/Y ratio, draw ratio, processing speed, etc. Because far-infrared polypropylene fine-denier filaments have small slenderness, even small structural defects are easily amplified and deteriorated during deformation processing. In addition, far-infrared PP-POY strips are higher than polyester, and the breakage rate generated during bombing is low. With less wool, you must choose a relatively low processing speed. In addition, since the far-infrared fine-denier polypropylene has low bending strength and can be fully deformed only under low tension, the selection of the stretching ratio should not be too large. The reasonable deformation process should ensure that the obtained DTY is substantially free of wool and stiffening. , tight wire, and easy to produce, unwind, stable production process, low breakage rate.
Based on the above considerations, the far-infrared POY stretching false twisting process is determined. See Table 6. The quality index of DTY is shown in Table 7. The far-infrared DTY developed by the weaving unit test has good weaving performance and is in full compliance. Post-processing requirements Table 6 Far-infrared PP-POY main deformation process conditions Fiber specification Stretch ratio False deformation speed / Table 7 Far-infrared PP-DTY fiber quality index Tah7ThequalityindexofFIPP-DTY Fiber specification Line density / Line density e / Strength Uniform X,% elongation unevenness KE,%KB,%(dtex 3 Conclusion The high-speed spinning process is used to develop far-infrared fine-denier polypropylene. The spinning temperature range is narrower, the temperature control needs to be stricter, and the spinning temperature should be controlled. 258C should maintain its crystal structure mainly in quasi-hexagonal crystal form. It is recommended that the spinning speed should not exceed 2. Develop far-infrared polypropylene on non-polypropylene special spinning equipment, and the side blowing temperature should be reduced accordingly, which is suitable for the research system. The cooling condition is: the side blowing temperature is 18C, and the speed is about 0.4m/s. Increasing the oiling position of the bundle is beneficial to reduce the spinning tension and improve the package quality. The better oiling position of the bundle is 920mm from the spinneret. e system of the present study, the deformation process is preferred: The first
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