A POK monofilament and its melt spinning process

Abstract

The present application relates to the field of POK material preparation, and in particular to a POK monofilament and its melt spinning process. The melt spinning process comprises the following steps: feeding the raw material components into a three-stage gradual single screw extruder without a mixing structure to melt and extrude the melt through blending, and the plasticized uniform melt is quantitatively extruded into the spinning assembly so that the primary monofilament is extruded through the spinneret of the spinning assembly, and the polyketone primary monofilament is spun; after the polyketone primary monofilament is cooled and formed by 50-60°C cooling water, two drafting treatments are carried out successively under 80-85°C hot water conditions and 140-150°C hot air conditions; finally, it is shaped under 150-170°C hot air conditions to obtain the POK monofilament. Using the spinning process scheme of the present application, the POK polymer monofilament has good spinnability and is not easy to break during the spinning process, and high-quality POK polymer monofilaments with uniform wire diameter, smooth surface, no crystal points, and excellent mechanical properties can be obtained on a large scale. The spinning process of the present application is simple and convenient to operate, without difficult operations and expensive raw materials, and can be applied to large-scale industrial production.

Description

Technical Field

[0001] The present application relates to the field of POK material preparation, and in particular to a POK monofilament and a melt spinning process thereof. Background Art

[0002] POK polymer, also known as polyketone in English, is a new type of thermoplastic engineering plastic. It belongs to semi-crystalline aliphatic polyketone. The linear molecular chain structure produced by the perfect alternation of carbon monoxide and olefins gives it balanced properties, mainly including hydrolysis resistance, impact resistance, wear resistance, chemical resistance, and gas barrier properties, making this polymer widely applicable to various types of products.

[0003] At present, only Hyosung of South Korea mass-produces POK fibers in the world. The relevant patents applied for by Hyosung of South Korea (for example, the application number KR1020100133500, the name of the preparation method of polyketon fiber) also disclose the corresponding preparation scheme of POK silk used by the company. For the research on the preparation process of POK fiber, there is also the preparation method of polyketone fiber disclosed in US Patent US5820806, which adopts wet spinning process. In addition, the current application of POK at home and abroad is limited to large-scale products such as plastics of various shapes and pipes and rods. Most of the production process development of POK fibers at home and abroad is also an alloy of POK and other polymers.

[0004] Since POK polymer has high viscosity, especially the longer the high temperature residence time, the higher the viscosity will be, and it is accompanied by gelation and carbonization phenomena, so it is very difficult to spin it. That is, its spinnability is very poor, the spinning process is prone to breakage, and the drafting is poor. The monofilament will show problems such as degradation, agglomeration, and yellowing defects during the spinning process, which makes it very difficult to produce monofilaments on an industrial scale.

[0005] At present, there is no corresponding report on other new commercial large-scale production of POK monofilaments to break the market monopoly of existing POK fiber production. In particular, the development of a new spinning process that can produce POK monofilaments with uniform diameter, smooth surface without crystal points, excellent mechanical properties, good spinnability and not easy to break on a large scale, and simple operation and convenient preparation process is still blank. Therefore, the development of a new spinning process that can produce POK monofilaments with uniform diameter, smooth surface without crystal points, excellent mechanical properties, good spinnability and not easy to break on a large scale, and simple operation and convenient preparation process is exactly the problem that those skilled in the art are committed to solving. Summary of the invention

[0006] In order to solve the problems of the prior art mentioned in the technical background, the present application provides a melt spinning process of POK monofilament, and its technical solution is as follows: The present application provides a melt spinning process of a POK monofilament, which comprises the following steps: Spinning: The raw material components are fed into a single screw extruder to be blended and melted to extrude the melt, and the uniformly plasticized melt is quantitatively extruded into a spinning assembly so that the primary monofilaments are extruded through the spinneret of the spinning assembly, and the polyketone primary monofilaments are spun; Shaping: After the polyketone primary monofilament is cooled and formed by cooling water at 50-60°C, it is subjected to two drawing treatments in 80-85°C hot water and 140-150°C hot air conditions in sequence; finally, it is shaped by hot air at 150-170°C to obtain the POK monofilament; The raw material components include polyketone chips and calcium stearate lubricant; in the single-screw extruder, the screw is a three-stage gradual change type without a mixing structure, the compression ratio of the screw is 2.5-2.8, the aspect ratio is 25-30, the temperature of each zone in the single-screw extruder is 205-215°C, and the screw pressure is 8-10MPa; in the two-pass drawing treatment, the total drawing multiple is 5-5.5 times, and the drawing multiple under the 80-85°C hot water condition accounts for 80-85% of the total drawing multiple.

[0007] In some embodiments, the calcium stearate lubricant accounts for 0.05-0.1% by weight of the polyketone slice.

[0008] In some embodiments, the polyketone chips have a melt index of 35 g / 10 min (220° C. / 2.16 kg).

[0009] In some embodiments, the raw material components consist of polyketone chips and calcium stearate lubricant.

[0010] In some embodiments, in the single-screw extruder, the three-stage gradual-change screw without a mixing structure is respectively a feeding section, a compression section and a metering section along the material transmission direction (i.e., along the length direction from feeding to discharging); wherein the length of each section of the feeding section, the compression section and the metering section accounts for 35%, 30% and 35% of the total length of the screw, respectively; along the material transmission direction, the depth of the thread groove of the feeding section and the metering section remains unchanged, the depth of the thread groove of the compression section gradually changes from deep to shallow, and there are no cylindrical pins with protrusions or diamond block mixing structures on the compression section and the metering section.

[0011] In some embodiments, a drying step is also included: drying the raw material components at (85-95)°C for more than 3 hours to remove surface moisture.

[0012] In some embodiments, the steps include: Dry the raw material components in a hub honeycomb dehumidifier at (85-95)°C for more than 3 hours; The raw material components are fed into a three-stage gradual change single screw extruder without a mixing structure to melt and extrude the melt, and the uniformly plasticized melt is quantitatively extruded into a spinning assembly through a metering pump, so that the primary monofilament is extruded through the spinneret of the spinning assembly to spin the polyketone primary monofilament; After the polyketone primary monofilament is cooled and formed by cooling water at 50-60°C, it is first drawn in a hot water tank at 80-85°C, and then drawn in a hot air box at 140-150°C; in the two-drawing treatment, the total drawing multiple is 5-5.5 times, and the drawing multiple under the 80-85°C hot water condition accounts for 80-85% of the total drawing multiple; The drawn monofilament enters a hot air oven at 150-170° C. for shaping to obtain the POK monofilament.

[0013] In some embodiments, a winding step is also included: the shaped monofilaments are oiled and cooled, and then wound onto a reel in sequence for use.

[0014] The present application also provides a POK monofilament, which is produced by the melt spinning process of the POK monofilament as described above.

[0015] In some embodiments, the diameter of the POK monofilament is 0.08-1.5 mm.

[0016] Compared with the prior art, the melt spinning process of POK monofilament provided in this application has the following beneficial effects: By adopting the spinning process scheme of the present application, the POK polymer monofilament has good spinnability and is not easy to break during the spinning process, and high-quality POK polymer monofilament with uniform wire diameter, smooth surface without crystal points, and excellent mechanical properties can be produced on a large scale. The spinning process of the present application scheme is simple and convenient to operate, without difficult operations and expensive raw materials, and can be applied to large-scale industrial production. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0018] The present application provides an implementation example of a melt spinning process of a POK monofilament, and the specific steps are as follows: 1. POK chips with a melt index of 35g / 10min (220℃ / 2.16kg) were used as the melt extrusion material. In order to improve the fluidity and extrusion stability of the melt, 0.05-0.1% of calcium stearate lubricant by weight of the POK chips was added to the POK chips, and the chips were dried in a wheel hub honeycomb dehumidifier at (85-95)℃ for more than 3 hours to remove surface moisture.

[0019] 2. Feeding the raw material components into a single screw extruder, blending and melting to extrude the melt, obtaining a uniformly plasticized melt, and quantitatively extruding the uniformly plasticized melt into each spinning assembly through a metering pump, and finally extruding polyketone primary monofilaments through a spinneret; Among them, a specific single-screw extruder is used for melt extrusion. The screw is a three-stage gradual type without a mixing structure. The compression ratio of the screw is controlled between 2.5-2.8, the aspect ratio is between 25-30, the temperature of each zone in the single-screw extruder is controlled between 205-215°C, and the screw pressure is controlled to 8-10MPa in order to increase the shear force and improve the fluidity of the melt.

[0020] Among them, the three-stage gradual change screw without mixing structure is a feed section, a compression section and a metering section in the material transmission direction; wherein the length of each section of the feed section, the compression section and the metering section accounts for 35%, 30% and 35% of the total length of the screw respectively; along the material transmission direction, the thread groove depth of the feed section and the metering section remains unchanged, the thread groove depth of the compression section gradually changes from deep to shallow, and there are no cylindrical pins with protrusions or diamond-shaped block mixing structures on the compression section and the metering section. Among them, the diameter of the screw is D, the pitch of the threaded part of the screw is equal, the pitch is 1D (the pitch is equal to the diameter of the screw), the helix angle is 17.66°, the screw ridge width is 0.1D (i.e. 0.1 times the diameter of the screw), and the screw groove depth is 0.15-0.20D.

[0021] 3. The polyketone nascent monofilament enters a 50-60°C water bath for rapid cooling and molding; 4. After the cooled and formed nascent monofilament is pulled by the pulling roller, it is first drawn in a hot water tank at 80-85℃, and then enters a hot air box at 140-150℃ for a second drawing; in the two drawing treatments, the total drawing multiple is 5-5.5 times, and the drawing multiple under the condition of 80-85℃ hot water accounts for 80-85% of the total drawing multiple. The drawn monofilament enters a hot air box at 150-170℃ for shaping in order to eliminate certain internal stress and improve the thermal stability of the monofilament.

[0022] 5. Finally, after oiling and cooling, the monofilament can be rolled up onto the reel in order for later use.

[0023] The diameter of the obtained monofilament can be controlled to any value between 0.08-1.5 mm according to the requirements of product design.

[0024] The present application also provides the following embodiments and comparative examples: Example 1 1. Raw materials and preparation: The raw material components consist of POK chips with a melt index of 35 g / 10 min (220° C. / 2.16 kg) and calcium stearate lubricant, and the amount of lubricant added is 0.05% of the weight of the POK chips.

[0025] 2. Preparation process: (1) POK slices were mixed with calcium stearate lubricant and then dried in a wheel hub honeycomb dehumidifier at 90 °C for 4 h.

[0026] (2) feeding the raw material components into a three-stage gradient single screw extruder without a mixing structure to melt and extrude the melt, and the uniformly plasticized melt is quantitatively extruded into a spinning assembly through a metering pump, so that the primary monofilaments are extruded through the spinneret of the spinning assembly to obtain polyketone primary monofilaments; and then the polyketone primary monofilaments are placed in a 50° C. water bath for rapid cooling and forming; The screw is a three-stage gradual change type without a mixing structure, the compression ratio of the screw is 2.5, the aspect ratio is 25, the temperature of each zone is set at 205-210°C, and the screw pressure is controlled at 8MPa. Specifically: The three-stage gradual change screw without mixing structure is composed of the feed section, compression section and metering section in the material transmission direction; wherein, the length of each section of the feed section, compression section and metering section accounts for 35%, 30% and 35% of the total length of the screw respectively; along the material transmission direction, the thread groove depth of the feed section and metering section remains unchanged, the thread groove depth of the compression section gradually changes from deep to shallow, and there are no cylindrical pins with protrusions or diamond-shaped block mixing structures on the compression section and metering section. The diameter of the screw is D, the pitch of the threaded part of the screw is equal, the pitch is 1D, the helix angle is 17.66°, the screw ridge width is 0.1D, and the screw groove depth is 0.15D.

[0027] The single screw extruder has 5 sections of barrel along the material conveying direction, namely, zone 1 to zone 5 along the material conveying direction, and the temperature of each zone is set at 205-210℃. The temperatures from zone 1 to zone 5 are 205℃, 208℃, 210℃, 210℃, and 210℃ respectively. Among them, the feed port is located in zone 1.

[0028] (3) After cooling, the nascent monofilament is pulled by a pulling roller and first enters a hot water tank at 80°C for a first stretching, with a stretching multiple of 4.25 times. It then enters a hot air box at 140°C for a second stretching, and finally the total stretching multiple of the second stretching reaches 5.25 times. The stretched monofilament enters a hot air box at 150°C for shaping. After oiling and cooling, the monofilament is wound onto a bobbin.

[0029] Example 2 1. Raw materials and preparation: Raw materials and preparation: The raw material components consist of POK chips with a melt index of 35g / 10min (220℃ / 2.16kg) and calcium stearate lubricant. The lubricant addition amount is 0.08% of the weight of the POK chips.

[0030] 2. Preparation process: (1) POK slices were mixed with calcium stearate lubricant and then dried in a wheel hub honeycomb dehumidifier at 90 °C for 4 h.

[0031] (2) feeding the raw material components into a three-stage gradient single screw extruder without a mixing structure to melt and extrude the melt, and the uniformly plasticized melt is quantitatively extruded into a spinning assembly through a metering pump, so that the primary monofilaments are extruded through the spinneret of the spinning assembly to obtain polyketone primary monofilaments; and then the polyketone primary monofilaments are placed in a 55° C. water bath for rapid cooling and forming; The screw is a three-stage gradual change type without a mixing structure, the compression ratio of the screw is 2.65, the aspect ratio is 28, the temperature of each zone is set at 208-212°C, and the screw pressure is controlled at 9MPa. Specifically: The three-stage gradual change screw without mixing structure is composed of the feed section, compression section and metering section in the material transmission direction; wherein the length of each section of the feed section, compression section and metering section accounts for 35%, 30% and 35% of the total length of the screw respectively; along the material transmission direction, the thread groove depth of the feed section and metering section remains unchanged, the thread groove depth of the compression section gradually changes from deep to shallow, and there are no cylindrical pins with protrusions or diamond-shaped block mixing structures on the compression section and metering section. The diameter of the screw is D, the pitch of the threaded part of the screw is equal, the pitch is 1D, the helix angle is 17.66°, the screw ridge width is 0.1D, and the screw groove depth is 0.18D.

[0032] The single screw extruder has 5 sections of barrel along the material conveying direction, namely, zone 1 to zone 5 along the material conveying direction, and the temperature of each zone is set at 208-212℃. The temperatures from zone 1 to zone 5 are 208℃, 210℃, 212℃, 212℃, and 212℃ respectively. Among them, the feed port is located in zone 1.

[0033] (3) After cooling, the newly-spun monofilament is pulled by a pulling roller and first enters a hot water tank at 83°C for a first stretching, with a stretching multiple of 4.45 times. It then enters a hot air box at 145°C for a second stretching, and finally the total stretching multiple of the second stretching reaches 5.4 times. After stretching, the monofilament enters a hot air box at 160°C for shaping. After oiling and cooling, the monofilament is wound onto a bobbin.

[0034] Example 3 1. Raw materials and preparation: Raw materials and preparation: The raw material components consist of POK chips with a melt index of 35g / 10min (220℃ / 2.16kg) and calcium stearate lubricant. The amount of lubricant added is 0.1% of the weight of the POK chips; 2. Preparation process: (1) POK slices were mixed with calcium stearate lubricant and then dried in a wheel hub honeycomb dehumidifier at 90 °C for 4 h.

[0035] (2) feeding the raw material components into a three-stage gradient single screw extruder without a mixing structure to melt and extrude the melt, and the uniformly plasticized melt is quantitatively extruded into a spinning assembly through a metering pump, so that the primary monofilaments are extruded through the spinneret of the spinning assembly to obtain polyketone primary monofilaments; and then the polyketone primary monofilaments are placed in a 60° C. water bath for rapid cooling and forming; The screw is a three-stage gradual change type without a mixing structure, the compression ratio of the screw is 2.8, the aspect ratio is 30, the temperature of each zone is set at 210-215°C, and the screw pressure is controlled at 10MPa. Specifically: The three-stage gradual change screw without mixing structure is composed of the feed section, compression section and metering section in the material transmission direction; wherein the length of each section of the feed section, compression section and metering section accounts for 35%, 30% and 35% of the total length of the screw respectively; along the material transmission direction, the thread groove depth of the feed section and metering section remains unchanged, the thread groove depth of the compression section gradually changes from deep to shallow, and there are no cylindrical pins with protrusions or diamond-shaped block mixing structures on the compression section and metering section. The diameter of the screw is D, the pitch of the threaded part of the screw is equal, the pitch is 1D, the helix angle is 17.66°, the screw ridge width is 0.1D, and the screw groove depth is 0.20D.

[0036] There are 5 sections of cylinder along the material conveying direction, namely, zone 1 to zone 5, and the temperature of each zone is set at 210-215℃. The temperatures from zone 1 to zone 5 are 210℃, 212℃, 215℃, 215℃, and 215℃ respectively. The feeding port is located in zone 1.

[0037] (3) After cooling, the newly-spun monofilament is pulled by a pulling roller and first enters a hot water tank at 85°C for a first stretching, with a stretching multiple of 4.65 times. It then enters a hot air box at 150°C for a second stretching, and finally the total stretching multiple of the second stretching reaches 5.5 times. After stretching, the monofilament enters a hot air box at 170°C for shaping. After oiling and cooling, the monofilament is wound onto a bobbin.

[0038] Comparative Example 1 (no lubricant added): The only difference from Example 1 is that in the raw materials and preparation steps, only POK slices are used, no lubricant is added, and other preparation process parameters are the same as those in Example 1.

[0039] Comparative Example 2 (too much calcium stearate lubricant added): The only difference from Example 1 is that in the raw material and preparation steps, the amount of calcium stearate lubricant added is 0.2% of the weight of the POK slices. Other preparation process parameters are the same as those of Example 1, except that the amount of lubricant added is larger.

[0040] Comparative Example 3 (small amount of calcium stearate lubricant added): The only difference from Example 1 is that in the raw material and preparation steps, the amount of calcium stearate lubricant added is 0.04% of the weight of the POK slices. The other preparation process parameters are the same as those of Example 1, except that the amount of lubricant added is slightly smaller.

[0041] Comparative Example 4 (using a three-stage gradual change single screw extruder with a pin mixing structure): The only difference from Example 1 is that a three-stage gradual change single screw extruder with a pin mixing structure is used to replace the three-stage gradual change single screw extruder without a mixing structure in Example 1, that is, the metering section of the screw is provided with a cylindrical pin mixing structure with a protrusion, and the specific position of the cylindrical pin mixing structure with a protrusion is located at the end of the metering section, accounting for about 5% of the length of the metering section.

[0042] Other preparation process parameters are the same as those in Example 1.

[0043] Comparative Example 5 (compression ratio is greater than the limited range): The only difference from Example 2 is that the compression ratio of the three-stage gradual change single screw extruder without a mixing structure is 3; the other preparation process parameters are the same as those of Example 2.

[0044] Comparative Example 6 (compression ratio is less than the limited range): The only difference from Example 2 is that the compression ratio of the three-stage gradual change single-screw extruder without a mixing structure is 2.3; the other preparation process parameters are the same as those in Example 2.

[0045] Comparative Example 7 (aspect ratio is less than the specified range): The only difference from Example 2 is that the length-to-diameter ratio of the three-stage gradual-change single-screw extruder without a mixing structure is 23; the other preparation process parameters are the same as those in Example 2.

[0046] Comparative Example 8 (the aspect ratio is greater than the limited range): The only difference from Example 2 is that the length-to-diameter ratio of the three-stage gradual-change single-screw extruder without a mixing structure is 33; the other preparation process parameters are the same as those in Example 2.

[0047] Comparative Example 9 (hot water tank drawing temperature is less than the limited range): The only difference from Example 3 is that the hot water tank drawing temperature is 75°C, and the other preparation processes are the same as Example 3.

[0048] Comparative Example 10 (hot water tank drawing temperature is greater than the limit range): The only difference from Example 3 is that the hot water tank drawing temperature is 90°C, and the other preparation processes are the same as Example 3.

[0049] Comparative Example 11 (total draft ratio is greater than the limited range): The only difference from Example 3 is that the total stretching multiple is 5.7 times, of which the stretching multiple of one stretching in the 85°C hot water tank accounts for 84.55% of the total stretching multiple (the proportion of one stretching in the hot water tank in this comparative example is consistent with that in Example 3), and the other preparation processes are the same as those in Example 3.

[0050] Comparative Example 12 (total draft ratio is less than the limited range): The only difference from Example 3 is that the total stretching multiple is 4.8 times, of which the stretching multiple of one stretching in the 85°C hot water tank accounts for 84.55% of the total stretching multiple (the proportion of one stretching in the hot water tank in this comparative example is consistent with that in Example 3), and the other preparation processes are the same as those in Example 3. The properties of the POK monofilaments obtained in the examples and comparative examples are shown in Table 1-2: Table 1 Performance of POK monofilament obtained in Examples 1-3

[0051] Table 2 Comparative Example 1 - Properties of the POK monofilament obtained

[0052] In Table 1-2, the test standard for breaking strength is GBT 14344-2008 Test method for tensile properties of chemical fiber filaments.

[0053] Table 1-2 Data analysis: The POK monofilament produced by the process scheme of the present application has excellent mechanical strength, smooth and uniform wire diameter and no crystal points, and there is no problem of wire breakage in production.

[0054] By comparing the examples with the comparative examples, it can be clearly seen that the specific process parameters and screw structure adopted in the present application are crucial for preparing high-quality POK monofilaments, ensuring that the monofilaments have uniform and stable diameters, smooth surfaces and excellent mechanical properties.

[0055] In summary, the above-mentioned application scheme has the following innovative design concepts and effects: The present application adopts a three-stage gradual change single screw extruder without a mixing structure to blend and melt extrude the melt. Specifically, the compression ratio of the single screw extruder is controlled between 2.5-2.8, and the aspect ratio is between 25-30. The POK primary monofilament is spun under a low-temperature high-shear melt extrusion spinning process. After being cooled and formed by 50-60°C cooling water, it is stretched in two passes in a 80-85°C hot water tank and a 140-150°C hot air box. The total stretching multiple is controlled between 5-5.5 times. Finally, it is shaped in a 150-170°C hot air box to obtain a large-diameter monofilament. The monofilament diameter can be controlled to any value between 0.08-1.5mm according to the requirements of product design.

[0056] By adopting the spinning process scheme of the present application, the POK polymer monofilament has good spinnability and is not easy to break during the spinning process, and high-quality POK polymer monofilament with uniform wire diameter, smooth surface without crystal points, and excellent mechanical properties can be produced on a large scale. The spinning process of the present application scheme is simple and convenient to operate, without difficult operations and expensive raw materials, and can be applied to large-scale industrial production.

[0057] Technological innovation: 1. POK is a semi-crystalline polymer with high melt viscosity, poor fluidity, and great difficulty in spinning. It is prone to melt fracture, i.e., crystal point fibers, during extrusion. In order to improve its fluidity and extrusion stability, a specific proportion of calcium stearate lubricant is added for blending and spinning. The desired effect of this application is achieved by combining a specific formula of raw material components with a specific melt spinning process.

[0058] 2. The processing temperature range of POK is narrow. The longer the residence time at high temperature, the greater the viscosity will be, and it will be accompanied by gel and carbonization. Under the premise of ensuring plasticization, the material is suitable for low-temperature extrusion. In order to adapt to the processing characteristics of POK, this application adopts a specific single-screw extruder. The screw adopts a three-stage gradual change without a mixing structure, and focuses on controlling the compression ratio between 2.5-2.8 and the aspect ratio between 25-30. The screw with this structural design can ensure sufficient shear force and plasticization time, while avoiding the problem of the melt staying in the mixing zone for too long or residual gel and carbonized material in dead corners, thereby ensuring the stability of melt extrusion.

[0059] 3. In order to obtain monofilaments with uniform and stable wire diameters, it is extremely important to reasonably allocate the drawing temperature and the drawing multiple, especially the drawing in the hot water tank. The control of the thin neck point is particularly important. If the drawing temperature is lower than the specified range of this application or the drawing multiple is greater than the specified range of this application, stress whitening or even broken wires will occur. If the drawing temperature is greater than the specified range of this application or the drawing multiple is lower than the specified range of this application, the effective orientation will be reduced and even the thin neck cannot be completely achieved. Through the innovative design of the inventor of this application, combined with the state of the monofilament spun according to a specific process in the previous step, the drawing temperature of POK in the hot water tank is limited to 80-85°C, and the drawing multiple accounts for 80-85% of the total drawing multiple as the best process control point. This application controls the total drawing multiple of the two drawing steps in the drawing step, the drawing temperature and the drawing multiple in the first drawing, and optimizes the raw material formula, the optimized spinning process, and the optimization of the drawing and shaping process in the later stage to obtain the desired effect of the present application.

[0060] It should be noted that: The "sequentially along the material conveying direction" mentioned herein is a conventional way of expressing the order of screw elements in the art. It is well known in the art that the art generally defaults to expressing the order according to the material conveying direction, that is, the order of the processing steps.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A melt spinning process for POK monofilament, characterized in that: The following steps are involved: Spinning: The raw material components are fed into a single screw extruder to be blended and melted to extrude the melt, and the uniformly plasticized melt is quantitatively extruded into a spinning assembly so that the primary monofilaments are extruded through the spinneret of the spinning assembly, and the polyketone primary monofilaments are spun; Shaping: After the polyketone primary monofilament is cooled and formed by cooling water at 50-60°C, it is subjected to two drawing treatments in 80-85°C hot water and 140-150°C hot air conditions in sequence; finally, it is shaped by hot air at 150-170°C to obtain the POK monofilament; The raw material components include polyketone chips and calcium stearate lubricant; in the single-screw extruder, the screw is a three-stage gradual change type without a mixing structure, the compression ratio of the screw is 2.5-2.8, the aspect ratio is 25-30, the temperature of each zone in the single-screw extruder is 205-215°C, and the screw pressure is 8-10MPa; in the two-pass drawing treatment, the total drawing multiple is 5-5.5 times, and the drawing multiple under the 80-85°C hot water condition accounts for 80-85% of the total drawing multiple.

2. The melt spinning process of POK monofilament according to claim 1, characterized in that: The calcium stearate lubricant accounts for 0.05-0.1% of the weight of the polyketone slice.

3. The melt spinning process of POK monofilament according to claim 1, characterized in that: The melt index of the polyketone chips is 35 g / 10 min.

4. The melt spinning process of POK monofilament according to claim 1, characterized in that: The raw material components consist of polyketone slices and calcium stearate lubricant.

5. The melt spinning process of POK monofilament according to claim 1, characterized in that: In the single-screw extruder, the three-stage gradual-change screw without a mixing structure is a feeding section, a compression section and a metering section in sequence along the material transmission direction; Among them, the lengths of the feeding section, compression section and metering section account for 35%, 30% and 35% of the total length of the screw respectively; along the material transmission direction, the depths of the thread grooves of the feeding section and the metering section remain unchanged, the depth of the thread grooves of the compression section gradually decreases from deep to shallow, and there are no cylindrical pins with protrusions or diamond block mixing structures on the compression section and the metering section.

6. The melt spinning process of POK monofilament according to claim 1, characterized in that: The method also includes a drying step: drying the raw material components at (85-95)°C for more than 3 hours.

7. The melt spinning process of POK monofilament according to claim 1, characterized in that: The following steps are involved: Dry the raw material components in a hub honeycomb dehumidifier at (85-95)°C for more than 3 hours; The raw material components are fed into a three-stage gradual change single screw extruder without a mixing structure to melt and extrude the melt, and the uniformly plasticized melt is quantitatively extruded into a spinning assembly through a metering pump, so that the primary monofilament is extruded through the spinneret of the spinning assembly to spin the polyketone primary monofilament; After the polyketone primary monofilament is cooled and formed by cooling water at 50-60°C, it is first drawn in a hot water tank at 80-85°C, and then drawn in a hot air box at 140-150°C; in the two-drawing treatment, the total drawing multiple is 5-5.5 times, and the drawing multiple under the 80-85°C hot water condition accounts for 80-85% of the total drawing multiple; The drawn monofilament enters a hot air oven at 150-170° C. for shaping to obtain the POK monofilament.

8. The melt spinning process of POK monofilament according to claim 1, characterized in that: The process also includes a winding step: after the shaped monofilaments are oiled and cooled, they are wound onto a reel in sequence for later use.

9. A POK monofilament, characterized in that: The method is prepared by the melt spinning process of the POK monofilament as described in any one of claims 1 to 8.

10. The POK monofilament according to claim 9, characterized in that: The diameter of the POK monofilament is 0.08-1.5 mm.

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