A process for the production of melt-spun polyethylene industrial yarn

Abstract

The application discloses a production method of melt-spun polyethylene industrial yarn, and the melt-spun polyethylene industrial yarn has high breaking strength, and the strength is greater than or equal to 10.0 cN / dtex; and has high dpf, and the dpf is 10-30D. The production method comprises the following steps: raw material modification; then melt extrusion, liquid cooling, water removal, oiling and raw yarn winding; and finally stretching, setting and finished product winding. The application solves the problems of poor spinnability, short component replacement period (3-4 days) and low breaking strength of melt-spun HDPE fibers.

Description

Technical Field

[0001] This invention relates to a method for producing melt-spun polyethylene industrial yarn. Background Technology

[0002] In 1953, K. Ziegler in Germany used titanium tetrachloride-triethylaluminum as an initiator to coordinate polymerize ethylene into high-density polyethylene (HDPE) under mild temperature and pressure conditions. HDPE is characterized by few branches (1-3 branches / 1000 carbon atoms), high crystallinity (about 90%), and high melting point (125-135℃).

[0003] Ultra-high molecular weight polyethylene (UHMWPE) fiber filaments prepared by solution (gel) spinning can be used to produce high-strength, high-modulus fibers through super-stretching (stretch ratio of over 50). These fibers are characterized by strength > 3 GPa and tensile modulus > 100 GPa. However, the solution spinning process of UHMWPE fibers is complex, with high raw material and processing costs, low spinning yield, and environmental pollution issues. The price of the finished product is more than ten times that of ordinary polyethylene fibers.

[0004] HDPE and UHMWPE have similar molecular structures and good compatibility. There is considerable research on their blending modification, with related authorized invention patents including: Melt spinning blends of UHMWPE and HDPE and fibers madetherefrom, High molecular weight polymer nucleating agent modified ultra-high molecular weight polyethylene blends, and a dense, transcrystalline, ultra-strong, and ultra-wear-resistant polyethylene composite material and its preparation method. Generally, the limiting axial modulus (calculated value) of fiber-forming polymers is in the range of 100-350 GPa, while the modulus obtained by traditional melt spinning and stretching processes is approximately 10% of these values. Therefore, to achieve a high-strength structure in polyethylene fibers, they need high molar mass, as well as highly straightened molecular chains and sufficient molecular chain overlap to establish adequate intermolecular interactions.

[0005] Disadvantages of existing technology:

[0006] ① The melt flow rate (MFR) of spinning grade HDPE is mostly between 0.36-1.0 g / 10 min. Its poor fluidity in the molten state can easily cause problems such as excessive back pressure on the spinneret surface and rupture of the nascent filament melt during melt spinning and extrusion processing, resulting in poor spinnability. The poor fluidity can also easily cause a large amount of degraded HDPE melt to remain near the extrusion holes of the spinneret, resulting in a short component replacement cycle (3-4 days).

[0007] ② Regardless of whether the polyethylene monofilament is produced by water cooling process or the polyethylene multifilament is produced by air cooling process, its breaking strength is lower than 5.5cN / dtex, which is difficult to meet the requirements of the high-end market. Moreover, the excessively high post-stretch ratio is prone to frequent filament breakage, resulting in a high small roll rate and high consumption.

[0008] ③ Polyethylene multifilament can only be made of HDPE with high MFR, which is 20-25% more expensive than HDPE with low MFR. Alternatively, HDPE with low MFR can be used, and cooling masterbatch can be added during melt spinning and extrusion, which greatly weakens the strength of the multifilament. Furthermore, the blending effect of cooling masterbatch and main raw material, as well as the fluctuation of the quality of cooling masterbatch itself, all affect the quality stability of the final product.

[0009] ④ Ordinary polyethylene fiber filaments on the market have a large number of fibers and a small fineness (dpf) of about 4-8 denier. They are prone to producing fly filaments and fuzz during the subsequent weaving process; the products have a softer feel and lower stiffness. Summary of the Invention

[0010] The purpose of this invention is to provide a method for producing melt-spun polyethylene industrial yarn that solves the problems of poor spinnability, short component replacement cycle, and low breaking strength of melt-spun HDPE fibers.

[0011] The technical solution of this invention is:

[0012] A method for producing melt-spun polyethylene industrial yarn, characterized in that: the melt-spun polyethylene industrial yarn has high breaking strength, ≥10.0 cN / dtex; high dpf, where dpf is 10-30D, and dpf refers to the linear density of each filament; the production method includes:

[0013] Step 1: First, HDPE (E308) is quantitatively fed into the twin-screw extruder through the main feed screw. Then, the initiator titanium tetrachloride-trialkylaluminum TiCl4-Al(C2H5)3 is quantitatively fed into the twin-screw extruder through the first side feed to cause the HDPE to undergo a chain extension reaction, obtaining modified particle 1#. Then, particle 1# is quantitatively fed into the twin-screw extruder through the main feed screw. Then, HDPE (M691) is quantitatively fed into the twin-screw extruder through the first side feed. Finally, polyolefin elastomer POE (8003) is quantitatively fed into the twin-screw extruder through the second side feed to obtain the final modified HDPE raw material.

[0014] Step 2: Add the modified HDPE raw material to the hopper of a single-screw extruder, and perform melt spinning extrusion of the precursor yarn. The screw temperature is 225℃-245℃. The coolant mass ratio is polypropylene glycol diglycidyl ether:water = 10:90, and the liquid cooling temperature is 25℃±2℃. After dehydrating the precursor yarn using an industrial yarn water tray, apply oil to the precursor yarn using two oiling rollers. The emulsion concentration is 25%, and the antistatic agent accounts for 5% of the total emulsion mass. Rewind the precursor yarn. The total fineness of the nascent yarn is 2000-20000D, and the spinning speed is 40-120m / min.

[0015] Step 3: Post-stretching of the raw yarn, using a single-stage hot air stretching process in a double-layer hot air oven, with stretching temperatures ranging from 70-120℃ and stretching ratios of 12-14 times; stretching speed of 120-160m / min; relaxation heat setting in a double-layer hot air oven at a temperature of 80-130℃, with an underfeed rate of 5-10%; finished product winding.

[0016] The twin-screw extruder is a meshing co-rotating twin-screw extruder. The screw adopts a modular assembly structure, selecting a combination of shallow groove single-head forward thread element, reverse thread element, and kneading block. The reverse thread facilitates air removal.

[0017] The melt spinning extrusion of the raw yarn uses a screw with an aspect ratio of 25-28 and a helix angle of 17°42';

[0018] The specific method for applying the oil is as follows: Use deionized water with a conductivity of less than 15 μS / cm to prepare the synthetic fiber oiling agent CONOLANCP 120-C into an emulsion with a concentration of 20-25%, and then add 3-5% of the total mass of the emulsion as an antistatic agent, fatty alcohol ether phosphate ester MOA3P.

[0019] Specific winding method: The winding ratio refers to the number of turns of the yarn bobbin in one cycle of the yarn lock's back and forth movement. During the winding process, as the outer diameter of the yarn bobbin increases, the yarn angle gradually decreases and the winding ratio gradually increases, which can easily cause phenomena such as overlapping of opposite yarns and edge collapse. Moreover, the higher the oil content of the yarn bundle, the more mesh fibers on both sides of the yarn bobbin, and the more obvious the overlapping resonance.

[0020] To address the above issues, this invention, based on the yarn bundle linear density, winding speed, and the yarn bundle's inherent properties, precisely adjusts the internal parameters of the servo drive via a PLC program at precise timing. This ensures the winding ratio decreases arithmetically, maintaining it at approximately 6°, meaning that one cycle of the yarn lock's back-and-forth movement corresponds to six rotations of the winding machine's bobbin. During winding, since the yarn angle varies with the winding ratio and yarn outer diameter, this invention uses a thicker bobbin (Φ = 500mm) to achieve a smaller rate of angle change. The minimum yarn spacing is determined by the arithmetically varying winding ratio and yarn angle in actual production. Optimizing the yarn angle and minimum yarn spacing maximizes package weight and ensures smooth unwinding. The raw yarn requires a high-precision constant tension control system at the winding spindle position and a high-performance reciprocating head. The raw yarn winding tension is 0.08-0.10 g / D, and the finished yarn winding tension is 0.13-0.15 g / D. The spacing of the rabbit head heads is adjusted according to the total fineness of the raw yarn, ensuring high smoothness.

[0021] The optimal aging time for the initiator titanium tetrachloride-trialkylaluminum TiCl4-Al(C2H5)3 is 20-24 hours to ensure that the two components TiCl4 and Al(C2H5)3 react fully.

[0022] The screws of the co-rotating twin-screw extruder employ a modular assembly structure. A combination of shallow-groove single-head forward thread elements, reverse thread elements, and kneading blocks is selected. The reverse thread facilitates air removal. Spare parts in the screw assembly include various models of kneading blocks and thread elements. The kneading block models are K90° / 5 / 32, K60° / 5 / 32, and K45° / 5 / 32. The K90° kneading block has the strongest shearing and mixing effect. The kneading blocks are combined according to the material characteristics. Twelve kneading blocks are used before side feed 2, with angles of K45°, K45°, K45°, K60°, K60°, K60°, K60°, K90°, K90°, K90°, K90°, K90°, K90°, K90°, K90°, to ensure thorough mixing of the material. Three kneading blocks are used after side feed 2, with angles of K45°, K60°, and K90°.

[0023] This invention solves the problems of poor spinnability of melt-spun HDPE fibers, short component replacement cycle (3-4 days), and low tensile strength; the product of this invention has high tensile strength and high strength.

[0024] ≥10.0cN / dtex; high dpf, dpf is 10-30D.

[0025] The advantages of this invention also include:

[0026] (1) Blending chain extension polymerization reaction

[0027] HDPE was modified by chain extension and blending using a self-designed twin-screw extruder. First, an initiator TiCl4-Al(C2H5)3 was added in a quantitative amount to carry out the first step of chain extension chemical reaction. Then, HDPE and POE with high MFR were added in a quantitative amount to carry out the second step of blending modification. The amount of initiator, HDPE and POE added was continuously optimized to obtain modified HDPE raw materials with narrow molecular weight distribution and good flowability. The experimental results show that when the initiator, M691, and 8003 are added at 1.5%, 20%, and 10% of the main feedstock, respectively, the resulting modified HDPE raw material has better physical properties. The molecular weight free radical (MRF) increases to 8-10 g / 10 min (test standard GB / T 3682-2000), the molecular weight distribution decreases by 3-4% (test standard GB / T 36214.2-2018), the flowability is significantly improved, and the tensile yield stress is ≥30 MPa (test standard GB / T 1040.2-2006), which is about 20% higher.

[0028] (2) Optimization of the side feeding sequence

[0029] POE has a narrow molecular weight distribution and uniform short branches, which can effectively improve the flowability of HDPE without affecting its mechanical properties. However, its melting point and crystallization temperature are relatively low (between 60-80℃). There are two reasons for quantitatively adding it to the side feeder of the twin-screw extruder: Firstly, because the shear force in the twin-screw extruder is strong, reducing the residence time in the twin-screw extruder can effectively prevent POE from undergoing thermo-oxidative degradation and losing its blending effect, but it does not affect its dispersion effect in the blended chips. Secondly, the molecular structure of POE is similar to that of EPDM rubber. Adding POE at the end prevents it from undergoing a cross-linking reaction with HDPE under the action of the initiator, which would affect the linearity and regularity of the modified chips.

[0030] (3) Selection and combination optimization of twin-screw components

[0031] Taking into account factors such as the properties of auxiliary materials, the order of addition, and the venting method, the screw elements of the twin-screw extruder are optimally configured, which increases the residence time of the chain extension reaction of the two polyethylenes, reduces the residence time of POE, and ensures that POE can be uniformly dispersed in the blend system.

[0032] (4) Processing of high dpf polyethylene industrial yarn

[0033] ① An excessively large aspect ratio of the screw in melt spinning extrusion can cause the free end of the screw to flex and sag, resulting in uneven spacing between the screw and the barrel, which can cause difficulties in later production and maintenance. Modified chips, due to their improved fluidity, have a reduced aspect ratio from 30 to 25, and can also prevent degradation caused by prolonged heating.

[0034] ② Use two oiling rollers to apply oil to the raw yarn to ensure a high success rate of oiling and uniform oil content;

[0035] ③ During the winding process, based on the linear density of the filament bundle, the winding speed, and the physical properties of the filament bundle itself, the PLC program precisely adjusts the internal parameters of the servo drive at precise timing, so that the winding ratio decreases in an arithmetic manner and is always maintained at about 6°, optimizing the yarn angle and the minimum yarn spacing, maximizing the package weight, and ensuring smooth unwinding.

[0036] ④ Modified HDPE chips have excellent tensile properties. In post-stretching and heat setting, the three-stage stretching method is changed to a single-stage stretching method, and the stretching ratio is increased from the original 9-10 times to a maximum of 14 times. This reduces the use of two stretching machines and two drying ovens, saving about 400 kWh of electricity per day and reducing production costs.

[0037] (5) Product performance advantages

[0038] The component replacement cycle of melt-spun high-dpf polyethylene industrial yarn has been increased to 10-14 days, compared with the original 3-4 days. The losses from frequent start-ups and shutdowns and the small roll rate have been significantly reduced, and the finished product quality is stable. The breaking strength of high-dpf polyethylene industrial yarn is ≥10.0cN / dtex, which is nearly 50% higher. The mechanical properties have been significantly improved, which has enhanced the competitiveness of the product. The larger dpf makes the multifilament less prone to breakage during the subsequent weaving process, and the fabric has high stiffness and is not easily deformed.

[0039] The present invention will be further described below with reference to the embodiments. Detailed Implementation

[0040] Example 1

[0041] A method for producing melt-spun polyethylene industrial yarn is as follows:

[0042] Step 1: First, HDPE (E308) is quantitatively fed into the twin-screw extruder through the main feed screw. Then, the initiator titanium tetrachloride-trialkylaluminum TiCl4-Al(C2H5)3 is quantitatively fed into the twin-screw extruder through side feed 1. The initiator accounts for 1.5% of the main feed, resulting in modified particle 1#. Particle 1# is then quantitatively fed into the twin-screw extruder through the main feed screw. Next, HDPE (M691) is quantitatively fed into the twin-screw extruder through side feed 1. Finally, polyolefin elastomer POE (8003) is quantitatively fed into the twin-screw extruder through side feed 2. The addition amounts of M691 and 8003 account for 20% and 10% of the main feed, respectively, resulting in modified HDPE raw material. The melting temperatures of zones one to eight of the twin-screw extruder are 100℃, 110℃, 120℃, 130℃, 130℃, 120℃, 110℃, and 110℃, respectively.

[0043] Step 2: Add the modified HDPE raw material to the hopper of a single-screw extruder and perform melt spinning extrusion of the precursor yarn; the temperatures of each zone of the screw are 245℃, 235℃, 230℃, 225℃, and 225℃ respectively; the mass ratio of the coolant is polypropylene glycol diglycidyl ether:water = 10:90, and the cooling temperature is 10℃; after dehydrating the precursor yarn using an industrial yarn water tray, the precursor yarn is then oiled using two oiling rollers, with an emulsion concentration of 25% and an antistatic agent accounting for 5% of the total emulsion mass; the precursor yarn winding tension is 1300g, the spinning speed is 50m / min, and the precursor yarn specification is 13000D / 96F;

[0044] Step 3: Post-stretching of the raw yarn, stretching oven temperature is 100℃, stretching ratio is 13 times, heat setting oven temperature is 110℃, underfeed rate is 5%, stretching speed is 120m / min (three pulls), winding tension of the take-up machine is 1500g, and the product yarn specification is 1000D / 96F.

[0045] The twin-screw extruder is a co-rotating twin-screw extruder with a modular screw structure. It employs a combination of shallow-groove single-head forward thread elements, reverse thread elements, and kneading blocks. The reverse thread facilitates air removal. The melt-spinning extrusion of the raw yarn uses a screw with a length-to-diameter ratio of 25 and a helix angle of 17°42'. The screw of the co-rotating twin-screw extruder uses a modular screw structure. It employs a combination of shallow-groove single-head forward thread elements, reverse thread elements, and kneading blocks. The reverse thread facilitates air removal. Spare parts in the screw assembly include various models of kneading blocks and thread elements. The kneading block model is K90°.

[0046] The kneading blocks of K90° (K45° / 5 / 32, K60° / 5 / 32, K60° / 5 / 32, K90°) have the strongest shearing and mixing effect. The kneading blocks are combined according to the material characteristics. Twelve kneading blocks are used before side feeding 2, with angles of K45°, K45°, K45°, K60°, K60°, K60°, K60°, K90°, K90°, K90°, K90°, K90°, K90°, K90°, to ensure thorough mixing of the material. Three kneading blocks are used after side feeding 2, with angles of K45°, K60°, and K90°.

[0047] The specific method for applying the oil is as follows: use deionized water with a conductivity of less than 15 μS / cm to prepare the synthetic fiber oiling agent CONOLANCP 120-C into an emulsion with a concentration of 25%, and then add 5% of the total mass of the emulsion as an antistatic agent, fatty alcohol ether phosphate ester MOA3P.

[0048] The specific winding method is as follows: The internal parameters of the servo drive are precisely adjusted at precise timing by the PLC program to make the winding ratio decrease arithmetically and always maintain it at 6°, that is, the yarn bobbin of the winding machine rotates 6 times for one cycle of the wire lock's back and forth movement. During the winding process, since the yarn angle changes with the winding ratio and the outer diameter of the yarn, a bobbin with Φ=500mm is used to obtain a smaller rate of angle change.

[0049] Example 2

[0050] The following is a method for producing high-strength, high-dpf polyethylene industrial yarn:

[0051] Step 1: First, HDPE (E308) is quantitatively fed into the twin-screw extruder through the main feed screw. Then, the initiator titanium tetrachloride-trialkylaluminum TiCl4-Al(C2H5)3 is quantitatively fed into the twin-screw extruder through side feed 1. The initiator accounts for 1.5% of the main feed, resulting in modified particle 1#. Particle 1# is then quantitatively fed into the twin-screw extruder through the main feed screw. Next, HDPE (M691) is quantitatively fed into the twin-screw extruder through side feed 1. Finally, polyolefin elastomer POE (8003) is quantitatively fed into the twin-screw extruder through side feed 2. The addition amounts of M691 and 8003 account for 20% and 10% of the main feed, respectively, resulting in modified HDPE raw material. The melting temperatures of zones one to eight of the twin-screw extruder are 100℃, 110℃, 120℃, 130℃, 130℃, 120℃, 110℃, and 110℃, respectively.

[0052] Step 2: Add the modified HDPE raw material to the hopper of a single-screw extruder. The temperatures of each zone of the screw are 245℃, 235℃, 230℃, 225℃, and 225℃, respectively. The coolant mass ratio is polypropylene glycol diglycidyl ether:water = 10:90, and the cooling temperature is 10℃. After dehydrating the raw yarn using an industrial yarn water tray, the raw yarn is then oiled using two oiling rollers. The emulsion concentration is 25%, and the antistatic agent accounts for 5% of the total emulsion mass. The raw yarn winding tension is 1400g, the spinning speed is 50m / min, and the raw yarn specification is 14000D / 96F.

[0053] Step 3: Post-stretching of raw yarn. The temperature of the stretching oven is 110℃, the stretching ratio is 14 times, the temperature of the heat setting oven is 120℃, the underfeed rate is 5%, the stretching speed is 120m / min (three pulls), the winding tension of the take-up machine is 1500g, and the product yarn specification is 1000D / 96F.

[0054] The twin-screw extruder is a co-rotating twin-screw extruder with a modular screw structure. It employs a combination of shallow-groove single-head forward thread elements, reverse thread elements, and kneading blocks. The reverse thread facilitates air removal. The melt-spinning extrusion of the raw yarn uses a screw with a length-to-diameter ratio of 26 and a helix angle of 17°42'. The screw of the co-rotating twin-screw extruder uses a modular screw structure. It employs a combination of shallow-groove single-head forward thread elements, reverse thread elements, and kneading blocks. The reverse thread facilitates air removal. Spare parts in the screw assembly include various models of kneading blocks and thread elements. The kneading block model is K90°.

[0055] The kneading blocks of K90° (K45° / 5 / 32, K60° / 5 / 32, K60° / 5 / 32, K90°) have the strongest shearing and mixing effect. The kneading blocks are combined according to the material characteristics. Twelve kneading blocks are used before side feeding 2, with angles of K45°, K45°, K45°, K60°, K60°, K60°, K60°, K90°, K90°, K90°, K90°, K90°, K90°, K90°, to ensure thorough mixing of the material. Three kneading blocks are used after side feeding 2, with angles of K45°, K60°, and K90°.

[0056] The specific method for applying the oil is as follows: use deionized water with a conductivity of less than 15 μS / cm to prepare the synthetic fiber oiling agent CONOLANCP 120-C into an emulsion with a concentration of 25%, and then add 5% of the total mass of the emulsion as an antistatic agent, fatty alcohol ether phosphate ester MOA3P.

[0057] The specific winding method is as follows: The internal parameters of the servo drive are precisely adjusted at precise timing by the PLC program to make the winding ratio decrease arithmetically and always maintain it at 6°, that is, the yarn bobbin of the winding machine rotates 6 times for one cycle of the wire lock's back and forth movement. During the winding process, since the yarn angle changes with the winding ratio and the outer diameter of the yarn, a bobbin with Φ=500mm is used to obtain a smaller rate of angle change.

[0058] Example 3

[0059] The following is a method for producing high-strength, high-dpf polyethylene industrial yarn:

[0060] Step 1: First, HDPE (E308) is quantitatively fed into the twin-screw extruder through the main feed screw. Then, the initiator titanium tetrachloride-trialkylaluminum TiCl4-Al(C2H5)3 is quantitatively fed into the twin-screw extruder through side feed 1. The initiator accounts for 1.5% of the main feed, resulting in modified particle 1#. Particle 1# is then quantitatively fed into the twin-screw extruder through the main feed screw. Next, HDPE (M691) is quantitatively fed into the twin-screw extruder through side feed 1. Finally, polyolefin elastomer POE (8003) is quantitatively fed into the twin-screw extruder through side feed 2. The addition amounts of M691 and 8003 account for 20% and 10% of the main feed, respectively, resulting in modified HDPE raw material. The melting temperatures of zones one to eight of the twin-screw extruder are 100℃, 110℃, 120℃, 130℃, 130℃, 120℃, 110℃, and 110℃, respectively.

[0061] Step 2: Add the modified HDPE raw material to the hopper of a single-screw extruder. The temperatures of each zone of the screw are 245℃, 235℃, 230℃, 225℃, and 225℃, respectively. The coolant mass ratio is polypropylene glycol diglycidyl ether:water = 10:90, and the cooling temperature is 10℃. After dehydrating the raw yarn using an industrial yarn water tray, the raw yarn is then oiled using two oiling rollers. The emulsion concentration is 25%, and the antistatic agent accounts for 5% of the total emulsion mass. The raw yarn winding tension is 1450g, the spinning speed is 50m / min, and the raw yarn specification is 14500D / 96F.

[0062] Step 3: Post-stretching of raw yarn. The temperature of the stretching oven is 120℃, the stretching ratio is 14.5 times, the temperature of the heat setting oven is 130℃, the underfeed rate is 5%, the stretching speed is 120m / min (three pulls), the winding tension of the take-up machine is 1500g, and the product yarn specification is 1000D / 96F.

[0063] The twin-screw extruder is a co-rotating twin-screw extruder with a modular screw structure. It employs a combination of shallow-groove single-head forward thread elements, reverse thread elements, and kneading blocks. The reverse thread facilitates air removal. The melt-spinning extrusion of the raw yarn uses a screw with a length-to-diameter ratio of 28 and a helix angle of 17°42'. The screw of the co-rotating twin-screw extruder uses a modular screw structure. It employs a combination of shallow-groove single-head forward thread elements, reverse thread elements, and kneading blocks. The reverse thread facilitates air removal. Spare parts in the screw assembly include various models of kneading blocks and thread elements. The kneading block model is K90°.

[0064] The kneading blocks of K90° (K45° / 5 / 32, K60° / 5 / 32, K60° / 5 / 32, K90°) have the strongest shearing and mixing effect. The kneading blocks are combined according to the material characteristics. Twelve kneading blocks are used before side feeding 2, with angles of K45°, K45°, K45°, K60°, K60°, K60°, K60°, K90°, K90°, K90°, K90°, K90°, K90°, K90°, to ensure thorough mixing of the material. Three kneading blocks are used after side feeding 2, with angles of K45°, K60°, and K90°.

[0065] The specific method for applying the oil is as follows: use deionized water with a conductivity of less than 15 μS / cm to prepare the synthetic fiber oiling agent CONOLANCP 120-C into an emulsion with a concentration of 25%, and then add 5% of the total mass of the emulsion as an antistatic agent, fatty alcohol ether phosphate ester MOA3P.

[0066] The specific winding method is as follows: The internal parameters of the servo drive are precisely adjusted at precise timing by the PLC program to make the winding ratio decrease arithmetically and always maintain it at 6°, that is, the yarn bobbin of the winding machine rotates 6 times for one cycle of the wire lock's back and forth movement. During the winding process, since the yarn angle changes with the winding ratio and the outer diameter of the yarn, a bobbin with Φ=500mm is used to obtain a smaller rate of angle change.

[0067] In specific embodiments, when the post-stretch ratio is 14.5 times, filament breakage occurs more frequently during the stretching process. Examples 1 and 2 are more normal. The physical property data of the products obtained from the three examples are shown in the table below. As can be seen from the table, the high dpf polyethylene industrial filament obtained in Example 2 has the best mechanical properties.

[0068]

[0069] This demonstrates the superior technical effects of the present invention.

Claims

1. A method for producing melt-spun polyethylene industrial yarn, characterized by: The melt-spun polyethylene industrial yarn has high breaking strength, with a strength ≥10.0 cN / dtex; High dpf, dpf is 10-30D, dpf refers to the linear density of each filament; production methods include: Step 1: First, chain-extended and blended modified HDPE is quantitatively fed into the twin-screw extruder through the main feed screw. Then, the initiator titanium tetrachloride-trialkylaluminum TiCl4-Al(C2H5)3 is quantitatively fed into the twin-screw extruder through the first side feed to cause the HDPE to undergo a chain extension reaction, obtaining modified particles 1#. Then, modified particles 1# are quantitatively fed into the twin-screw extruder through the main feed screw. Then, high MFR HDPE is quantitatively fed into the twin-screw extruder through the first side feed. Finally, polyolefin elastomer POE is quantitatively fed into the twin-screw extruder through the second side feed to obtain the final modified HDPE raw material. Step 2: Add the modified HDPE raw material to the hopper of a single-screw extruder, and perform melt spinning extrusion of the precursor yarn. The screw temperature is 225℃-245℃. The coolant mass ratio is polypropylene glycol diglycidyl ether:water = 10:90, and the liquid cooling temperature is 25℃±2℃. After dehydrating the precursor yarn using an industrial yarn water tray, oil the precursor yarn using two oiling rollers. The emulsion concentration is 25%, and the antistatic agent accounts for 5% of the total emulsion mass. The precursor yarn is then wound up. The total fineness of the nascent yarn is 2000-20000D, and the spinning speed is 40-120m / min. Step 3: Post-stretching of the raw yarn, using a single-stage hot air stretching process in a double-layer hot air oven, with a stretching temperature of 70-120℃ and a stretching ratio of 12-14 times; stretching speed of 120-160m / min; relaxation heat setting in a double-layer hot air oven, with a heat setting oven temperature of 80-130℃ and an underfeed rate of 5-10%; finished product winding.

2. The method for producing melt-spun polyethylene industrial yarn according to claim 1, characterized in that: The twin-screw extruder is a meshing co-rotating twin-screw extruder. The screw adopts a modular assembly structure, selecting a combination of shallow groove single-head forward thread element, reverse thread element, and kneading block. The reverse thread facilitates air removal.

3. The method for producing melt-spun polyethylene industrial yarn according to claim 1, characterized in that: The melt spinning extrusion of the raw yarn uses a screw with an aspect ratio of 25-28 and a helix angle of 17°42'; The specific method of oiling: use deionized water with a conductivity of less than 15 μs / cm to prepare an emulsion of CONOLAN CP120-C synthetic fiber oiling agent with a concentration of 25%, and then add 5% of the total mass of the emulsion of antistatic agent fatty alcohol ether phosphate MOA3P. The specific winding method is as follows: The internal parameters of the servo drive are precisely adjusted by the PLC program at precise timing to reduce the winding ratio in an arithmetic manner, so that the winding ratio is always maintained at 6°, that is, the yarn bobbin of the winding machine rotates 6 times for one cycle of the wire lock's back and forth movement; during the winding process, since the yarn angle changes with the winding ratio and the outer diameter of the yarn, a bobbin with Φ=500mm is used to obtain a smaller rate of angle change; the winding tension of the raw yarn is 0.08-0.10g / D, and the winding tension of the finished yarn is 0.13-0.15g / D.

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