Polyamide (nylon) wire
DATE：2022/10/24 8:27:45 / READ： / SOURCE：This station
Polyamide (nylon) wire
Polyamide monofilament is used to be called nylon filament. The production method is the same as that of polyethylene wire and polypropylene wire. First, the polyamide material is plasticized and melted in the extruder, and then extruded through the die spinneret to form the monofilament preform. Then, it is cooled and shaped after hot stretching, which is the finished wire. The polyamide monofilament extrusion molding production line is shown in Figure 9-6. The structure and function of the auxiliary machine in the production line are identical to those of the auxiliary machine for PE filament extrusion molding.Polyamide monofilament has high tensile strength, abrasion resistance, good toughness, non-toxic and good chemical stability. Therefore, it is mostly used as fishing line, fishing net, rope, mesh bag, daily necessities, toothbrush, mosquito net, etc.
(1) Polyamide with a mass of 140000~160000 was selected for spinning. When the relative molecular weight is less than 14000, the fluidity of the molten material is too good, and the extrusion operation is difficult to form; When the relative molecular weight is greater than 160000, the melt has high viscosity, poor fluidity, and the wire is easy to break during drawing. PA1010 material from Tianjin Zhonghe Chemical Plant and Jilin Shijinggou Joint Chemical Plant is used to extrude PA monofilament.
(2) Generally, small single screw extruders with medium screw diameter of 45mm or 65mm are selected for equipment conditions. The screw structure is required to be equidistant and abrupt, and the length diameter ratio L/D=(20~25): 1. The compression ratio is 3. The structure of the forming die is shown in Figure 9-2.
The drive system in the traction and stretching device (see Figure 9-6) can be driven by three traction rollers and one speed regulating motor; Speed can also be adjusted separately. The speed ratio of the first traction stretching roller to the second traction stretching roller is 35 times; The speed ratio of the second traction stretching roll to the third traction stretching roll is 13 times. In order to ensure the constant coiling tension of the coiling wire, the coiling motor is required to be a torque motor.
(3) Forming process
① Extruder plasticizing raw material temperature control (from feeding section to homogenizing section) 130~160 ℃, 160~200 ℃, 200~240 ℃.
② Mold temperature of forming wire blank 230~250 ℃
③ The water temperature in the cooling and setting water tank for the wire blank is 25~35 ℃. The distance between the liquid level of cooling water and the spinneret hole is adjustable and controlled within the range of 15~40mm. The liquid level shall be stable during operation.
④ The rotation speed of three groups of traction stretching rolls is 45m/min for one group of rolls, 150m/min for two groups of rolls, and 200m/min for three groups of rolls.
⑤ The drawing temperature of the wire blank is about 95 ℃. To prevent the wire blank from sliding on the roll surface during drawing, the monofilament can be wound on the roll for several more cycles.
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