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Nylon monofilament shrinkage is directly proportional to hot box temperature

An important factor that affects the elasticity of nylon and ammonia air coated yarns is the stretch ratio of the spandex yarn. When using the same spandex, the elasticity of nylon and ammonia air coated yarn increases as the spandex stretch ratio increases. However, due to the general heat resistance of spandex, downstream customers still have heat treatment processes such as printing, dyeing and molding. If the stretch ratio is too high, it will easily lead to spandex breakage, resulting in horizontal lines or defects on the fabric surface. According to the customer's requirement for product elasticity, combined with the physical properties of spandex, the authors set the spandex stretch ratio to 3.3 times.

D/Y ratio is the ratio of friction line speed to output roller W2 line speed. too large or too small D/Y will easily lead to tangle or stiffness of nylon monofilament and affect the air coating effect of web ware. Therefore, choosing the right D/Y ratio is also one of the key points to ensure the web degree.

Hot box temperature.

The relevant data shows that the shrinkage of nylon monofilament is directly proportional to the hot box temperature. When the process conditions such as speed and nylon monofilament drafting ratio are kept constant, the curl shrinkage and curl stability of nylon filaments increase with the increase of hot box temperature, which affects the elasticity of coated filaments. However, if the temperature is too high, it will produce molten tight spot filaments, which will affect the air coating effect of the networker. In a comparative test, the nylon monofilament can maintain good elasticity and crimp when the processing speed is 720m/min and the hot box temperature is 170c.

Feeding angle and overfeed ratio.

The installation position of the networker directly affects the feeding angle of nylon ammonia coated yarn. The feeding angle is the angle between the yarn and the network channel before it enters the networker. Based on experience, the network works better when the feeding angle of nylon monofilament and spandex yarn is 15~25°.

The overfeed ratio (W1/W2) is the speed ratio between the second roller and the auxiliary roller, which will directly affect the tension of the yarn bundle. Within a certain range, the higher the overfeed ratio, the lower the tension of the filament bundle, the easier it is for the monofilament to saddle through the networker, and the network degree will rise. However, the overfeed ratio is at a certain extent, the monofilament tends to drift out of the web roller, leading to head breakage.

Therefore, when the feeding angle is 25° and the overfeed ratio (W/W2) is 1.080, the coated filament product has good webbing.

Web nozzle and web pressure.

The network effect that affects the quality of gold ammonia air coated wire mainly depends on the network nozzle structure [71. At present, domestic and foreign markets. There are many forms of network nozzles, including round, V-shaped, etc. Different forms of nozzles have a great impact on the difference in the quality of air-coated wire mesh, of which double circular and V-shaped nozzles have good network effects. In addition, the networker's hole type, aperture and length ratio will also affect the network effect. Round nozzles are particularly suitable for high-speed networks, so the authors chose a high-speed network nozzle with a 1.1 mm aperture.

Another important factor affecting the quality of nylon ammonia air-coated filaments is the network pressure. Compressed air has a great influence on the air packing process. Through the test, it was found that when the compressed air pressure was 0.05mpa, the filament bundle was still in a loose state and the monofilament could only be loosened and could not be connected. When the pressure reached 0.10mpa, the communication between nylon and spandex began to form, but the network degree and network fastness was low. As the pressure keeps increasing, when it reaches 0.15mpa or more, the compressed air has enough energy to drive the monofilament and form the network point after blowing away the filament. As the pressure increases, the gas injection speed also increases accordingly, the network degree also increases accordingly, the network point distribution tends to be uniform, and the looseness of the AC point changes with the change of air pressure and the change of AC degree. However, when the network degree reaches a certain value, the pressure increases again and the network degree no longer increases significantly because the pressure is too large and part of the kinetic energy forms useless vortices outside the filament.
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