A high-strength composite rope core and its preparation method

Abstract

The present invention provides a high-strength composite rope core, which includes an inner layer strand and an outer layer strand. The inner layer strand includes 5 composite steel wire core strands, 4 sisal-polyester double-coated yarns, and several sisal-modified polyvinyl alcohol single-coated yarns. Among them, 4 composite steel wire core strands are helically wrapped around another composite steel wire core strand. The sisal-polyester double-coated yarns are arranged between three adjacent composite steel wire core strands. The sisal-modified polyvinyl alcohol single-coated yarns are filled between the composite steel wire core strands, the sisal-polyester double-coated yarns and the outer layer strand. The cooperation of each layer structure not only greatly improves the strength of the rope core but also improves the oil storage effect inside the rope core. The present invention also provides a preparation method of the high-strength compressive composite rope core. The preparation method of this rope core has a simple and clear operation process, low equipment requirements, strong applicability, superior performance of the produced steel wire rope, and broad development prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of wire rope cores, and particularly relates to a high-strength composite rope core and a preparation method thereof. Background Art

[0002] A wire rope is a helical wire bundle formed by twisting steel wires that meet the requirements of mechanical properties and geometric dimensions together according to certain rules, and is composed of steel wires, a rope core, and grease. The wire rope has high strength, light self-weight, stable operation, and is not likely to break suddenly as a whole, and is reliable in work, and has a wide range of applications in daily life. Due to the unique performance of the wire rope, so far the wire rope is an essential material or component in the fields of metallurgy, mining, oil and gas drilling, machinery, chemical industry, aerospace, etc. Therefore, the quality of the wire rope is also concerned by multiple industries. Among them, the wire rope core is a key link to ensure the quality of the wire rope.

[0003] When the wire rope is applied at the engineering site, the rope core plays a role in radial support and reducing the pressure between strands, and plays a major role in maintaining the stable physical structure of the wire rope. At the same time, the wire rope core should also have good oil-holding capacity so as to release grease between the steel wires for lubrication and reduce the frictional force between the steel wires. Therefore, optimizing the structural design and raw material selection of the rope core can effectively improve the comprehensive performance of the wire rope. While improving the strength and flexibility of the rope core, it does not affect its oil absorption performance, which is of great significance for improving the overall performance of the rope core and even the wire rope, and further improving the use safety of the wire rope. Summary of the Invention

[0004] The purpose of the present invention is to provide a high-strength composite rope core and a preparation method thereof, which can effectively improve the overall strength of the rope core, improve the tensile resistance and flexibility, have good oil storage effect, and the preparation method is simple and easy to implement.

[0005] The present invention provides a high-strength composite rope core, which includes an inner layer strand and an outer layer strand. The inner layer strand includes 5 strands of composite steel wire core strands, 4 sisal-polyester double-coated yarns, and several sisal-modified polyvinyl alcohol single-coated yarns. Among them, 4 strands of composite steel wire core strands helically wrap and twist another strand of composite steel wire core strand. The sisal-polyester double-coated yarns are arranged between adjacent three strands of composite steel wire core strands. The sisal-modified polyvinyl alcohol single-coated yarns are filled between the composite steel wire core strands, the sisal-polyester double-coated yarns, and the outer layer strand. The composite steel wire core strand includes 7 galvanized steel wires and 6 brass-plated steel wires. Among them, 6 galvanized steel wires helically wrap and twist another galvanized steel wire. The brass-plated steel wires are arranged in the gaps between adjacent three galvanized steel wires. The outer layer strand includes several sisal-polyester double-coated yarns, and the sisal-polyester double-coated yarns helically wrap and twist the inner layer strand.

[0006] Preferably, the sisal-polyester double-covered yarn comprises a first sisal yarn, a first polyester filament and a second polyester filament. Its preparation method is to first feed the first polyester filament to cover the first sisal yarn to obtain a first covering layer, and then feed the second polyester filament to cover the outer layer of the first covering layer to obtain a second covering layer.

[0007] Preferably, the sisal-modified polyvinyl alcohol single-covered yarn comprises a second sisal yarn and a modified polyvinyl alcohol filament. The sisal-modified polyvinyl alcohol single-covered yarn is prepared by feeding the modified polyvinyl alcohol filament to cover the outer layer of the second sisal yarn.

[0008] More preferably, the modified polyvinyl alcohol filament is spun from polyvinyl alcohol modified by cellulose nanofibers and graphene oxide.

[0009] Even more preferably, the mass ratio of polyvinyl alcohol, cellulose nanofibers and graphene oxide is 100:6:1.

[0010] Preferably, phosphating treatment is performed on the outer surface of the galvanized steel wire to form a phosphating film on the surface of the galvanized steel wire, and the film weight of the phosphating film is 10 g / m 2. .

[0011] The present invention also provides a preparation method of a high-strength composite rope core, comprising the following steps:

[0012] Step 1, preparation of galvanized steel wire: Pickled carbon steel is pickled, dried after pickling, and then passed through a wire drawing machine after drying to draw the carbon steel into a steel wire with a predetermined diameter. The number of drawing passes is 7-10 passes; the die exit temperature during the wire drawing process of the steel wire is not higher than 300 °C. After drawing, the steel wire is subjected to zinc dipping heat treatment. The zinc bath temperature is 460 °C and the galvanizing time is 70 s; the galvanized steel wire after galvanizing treatment is redrawn through a wire drawing machine, and the compression ratio is selected to be 80-90%. After galvanizing, the steel wire is subjected to stabilization treatment to obtain the galvanized steel wire;

[0013] Step 2, preparation of brass-plated steel wire: Pickled carbon steel is pickled, dried after pickling, and then passed through a wire drawing machine after drying to draw the carbon steel into a steel wire with a predetermined diameter. After copper plating and galvanizing in sequence, thermal diffusion treatment is carried out, and then the steel wire is treated by phosphoric acid pickling to obtain the brass-plated steel wire;

[0014] Step 3, preparation of sisal-polyester double-covered yarn: Use high-strength industrial polyester filaments of 1100D-1300D as the first polyester filament, and use high-strength industrial polyester filaments of 1300D-1500D as the second polyester filament. The sisal fibers are woven into sisal yarns; First, feed the first polyester filament to cover the outer surface of the sisal yarn to obtain a first covering layer, and then feed the second polyester filament to cover the first covering layer to obtain a second covering layer, thereby obtaining the sisal-polyester double-covered yarn;

[0015] Step 4, sisal-modified polyvinyl alcohol single-coated yarn: sisal fibers are woven into sisal yarn, modified polyvinyl alcohol is wet-spun and then subjected to heat stretching treatment to obtain modified polyvinyl alcohol filaments, and the modified polyvinyl alcohol filaments are fed into the sisal yarn surface to be coated to obtain the sisal-modified polyvinyl alcohol single-coated yarn;

[0016] Step 5, preparation of inner layer strands: take 7 galvanized steel wires and 6 brass-plated steel wires, take one galvanized steel wire as the core wire, place the 6 brass-plated steel wires into a stranding machine and spirally wrap and twist the core wire, and then use the stranding machine to spirally wrap and twist the other 6 galvanized steel wires and the brass-plated steel wire to obtain a composite steel wire core strand, wherein each brass-plated steel wire is located between the core wire and two adjacent galvanized steel wires in the outer layer. Use the same method to prepare another 4 composite steel wire core strands, arrange 4 composite steel wire core strands and 4 sisal-polyester double-coated yarns at intervals, spirally wrap and twist another composite steel wire core strand through a stranding machine, and then take a number of sisal-modified polyvinyl alcohol single-coated yarns and continue to spirally wrap and twist until an inner layer strand of a predetermined diameter is formed;

[0017] Step 6: Preparation of outer strands: Take a number of sisal-polyester double-covered yarns and use a twisting machine to spirally wrap the inner strands to obtain the high-strength composite rope core.

[0018] Preferably, the modified polyvinyl alcohol comprises the following preparation steps:

[0019] Step 4.1: Weigh polyvinyl alcohol, cellulose nanofibers and graphene oxide according to proportion;

[0020] Step 4.2: Fully stir and disperse the cellulose nanofibers, graphene oxide and water, add polyvinyl alcohol, heat the solution to 90° C. and continue stirring for 4 hours to completely dissolve the polyvinyl alcohol, and then let it stand to defoam to obtain the modified polyvinyl alcohol.

[0021] Preferably, in step 4, during the wet spinning of modified polyvinyl alcohol, cooled methanol containing 5% by mass of calcium chloride is used as a coagulation solution, and the modified polyvinyl alcohol solution is injected into the flowing coagulation solution through a spinning syringe. After the formed fiber filaments are dried, they are immersed in the methanol solution again for 12 hours, taken out and dried in an oven, and then subjected to heat stretching treatment.

[0022] Preferably, the sisal-polyester double-covered yarn prepared in step 3 and the sisal-modified polyvinyl alcohol single-covered yarn prepared in step 4 are treated with oil.

[0023] The present invention has the following beneficial effects: By setting a composite structure of an inner strand and an outer strand, the inner strand is composed of a composite steel wire core strand, a sisal-polyester double-coated yarn, and a sisal-modified polyvinyl alcohol single-coated yarn. The cooperation of each layer structure not only greatly improves the strength of the rope core but also enhances the oil storage effect inside the rope core. The present invention uses a sisal-polyester double-coated yarn and a sisal-modified polyvinyl alcohol single-coated yarn. Sisal fibers have the characteristics of long length, high strength, good wear resistance, high oil absorption rate, etc. However, the product quality of sisal yarn fluctuates greatly, which will cause problems such as uneven diameter of the fiber rope core, large dispersion, and uneven strength. The form of using synthetic fibers to coat sisal yarn not only makes up for the deficiency of sisal yarn strength but also can reduce the burrs of sisal yarn. The tensile resistance of the coated yarn obtained after coating sisal yarn is increased by 30%-40%. At the same time, the sisal-polyester double-coated yarn or the sisal-modified polyvinyl alcohol single-coated yarn is more wear-resistant, corrosion-resistant, and the diameter is more stable, which has a better effect when used to prepare the rope core. In the present invention, the composite steel wire core strand is composed of galvanized steel wire and brass-plated steel wire. An independent contact rope core structure is adopted, and the brass-plated steel wire is arranged between the contact surfaces of the galvanized steel wires, which can increase the contact area between the steel wires. The brass-plated steel wire is closely attached to the inner and outer galvanized steel wires, increasing the contact area inside the composite steel wire core strand. The stress is evenly dispersed on the contact surface of the brass-plated steel wire and the galvanized steel wire, greatly improving the problem of stress concentration and enhancing the anti-fatigue effect of the rope core.

[0024] The present invention also provides a preparation method of the high-strength compressive composite rope core. The preparation method of this rope core has a simple and clear operation process, low equipment requirements, strong applicability, and the produced steel wire rope has excellent performance and broad development prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic structural diagram of a high-strength composite rope core of the present invention.

[0026] Figure 2 is Figure 1 a schematic structural diagram of the composite steel wire core strand in

[0027] In the figure: 1 - inner strand, 2 - outer strand, 3 - composite steel wire core strand, 4 - sisal-modified polyvinyl alcohol single-coated yarn, 5 - sisal-polyester double-coated yarn, 301 - galvanized steel wire, 302 - brass-plated steel wire. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] The following described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts shall fall within the protection scope of the present invention.

[0029] Such as Figure 1 、2 As shown, this embodiment provides a high-strength composite rope core, including an inner layer strand 1 and an outer layer strand 2. The inner layer strand 1 includes 5 composite steel wire core strands 3, 4 sisal-polyester double-covered yarns 5 and a plurality of sisal-modified polyvinyl alcohol single-covered yarns 4, wherein the 4 composite steel wire core strands 3 are spirally twisted with another composite steel wire core strand 3, the sisal-polyester double-covered yarn 5 is arranged between three adjacent composite steel wire core strands 3, and the sisal-modified polyvinyl alcohol single-covered yarn 4 is filled between the composite steel wire core strand 3, the sisal-polyester double-covered yarn 5 and the outer layer strand 2. The sisal-polyester double-covered yarn 5 includes a first sisal yarn, a first polyester filament and a second polyester filament, and the preparation method thereof is to first feed the first polyester filament to cover the first sisal yarn to obtain a first covering layer, and then feed the second polyester filament to cover the outer layer of the first covering layer to obtain a second covering layer. The sisal-modified polyvinyl alcohol single-coated yarn 4 comprises a second sisal yarn and modified polyvinyl alcohol filaments, and the sisal-modified polyvinyl alcohol single-coated yarn 4 is prepared by feeding modified polyvinyl alcohol filaments and coating the outer layer of the second sisal yarn. The sisal yarn is treated by coating, which not only maintains the high oil absorption effect of the sisal yarn, but also further enhances the strength and wear resistance of the sisal yarn. At the same time, the coating method can also reduce the burrs of the sisal yarn, reduce the shearing and singeing processes, and effectively solve the labor consumption of shearing and singeing and the waste of sisal fibers caused.

[0030] In particular, the modified polyvinyl alcohol filament is spun after polyvinyl alcohol is modified by cellulose nanofibers and graphene oxide. The mass ratio of polyvinyl alcohol, cellulose nanofibers and graphene oxide is 100:6:1. Pure polyvinyl alcohol (PVA) fibers prepared by wet spinning, melt spinning or electrospinning often have poor mechanical properties, which limits their practical use. Cellulose nanofibers (CNF) and graphene oxide (GO) are used as one-dimensional and two-dimensional anisotropic fillers, respectively, with high specific strength, high specific modulus, low specific gravity, small size effect and interface effect, which can effectively improve the mechanical properties of PVA fibers. After the addition of CNF and GO, the hydrogen bonds in the system will be enhanced, and the formation of hydrogen bonds between PVA and CNF and GO is a favorable condition for the formation of high-strength and high-modulus PVA fibers. Since the fiber surface prepared by pure PVA is smooth and the interior is dense, after the addition of CNF and GO, the surface of the fiber becomes rough and the interior becomes loose and porous. Therefore, hot stretching is required. After hot stretching, the diameter of the fiber becomes significantly smaller, and lines appear on the surface along the fiber direction, showing the anisotropy of its structure. At the same time, the holes inside the fiber become smaller and appear denser, which is of great help in improving the overall performance of the modified polyvinyl alcohol filament. After 3 times stretching at 175°C, the ultimate tensile strength of the modified polyvinyl alcohol filament can reach 1.5GPa, and the elongation is 25.3%, which is a considerable effect.

[0031] The composite steel wire core strand 3 includes 7 galvanized steel wires 301 and 6 brass-plated steel wires 302, wherein the 6 galvanized steel wires 301 are spirally twisted with another galvanized steel wire 301, and the brass-plated steel wire 302 is arranged in the gap between three adjacent galvanized steel wires 301. The outer strand 2 includes a plurality of sisal-polyester double-covered yarns 5, and the sisal-polyester double-covered yarns 5 are spirally twisted with the inner strand 1. In particular, the outer surface of the galvanized steel wire 301 is phosphated to form a phosphating film on the surface of the galvanized steel wire 301, and the film weight of the phosphating film is 10g / m 2. . The brass-plated steel wire 302 is arranged between the galvanized steel wires 301, and fits tightly with the galvanized steel wires 301, thereby increasing the contact area inside the composite steel wire core strand 3, and can evenly disperse the stress on the contact surface, thereby avoiding the problem of wire breakage caused by stress concentration. The brass-plated steel wire 302 has high toughness and plasticity, and can be more tightly plastically combined with the galvanized steel wire 301, thereby preventing wear and breakage in the early stage of the running-in of the two steel wires. The composite steel wire core strand 3 composed of the galvanized steel wire 301 and the brass-plated steel wire 302 has a good effect on improving the supporting capacity of the rope core. Furthermore, a layer of phosphating film is added to the surface of the galvanized steel wire 301. The phosphating film has the property of improving the friction performance of the metal surface and promoting sliding, and can improve the corrosion resistance and wear resistance of the rope-making steel wire. At the same time, the phosphate film is also porous, and lubricating grease can penetrate into the pores of the phosphate film, which is conducive to storing more grease inside the wire rope core. The combined effect of the phosphate film and grease can effectively improve the lubrication effect and anti-corrosion ability between the steel wires, thereby improving the wear resistance of the steel wire.

[0032] This embodiment also provides a method for preparing a high-strength composite rope core, which is used to prepare the high-strength composite rope core, comprising the following steps:

[0033] Step 1, preparation of galvanized steel wire: pickling the selected carbon steel, drying after pickling, and passing the carbon steel through a wire drawing machine after drying to draw it into a steel wire of a predetermined diameter, with 7-10 drawing passes; the die temperature during the steel wire drawing process is not higher than 300°C, and the steel wire is subjected to a galvanizing heat treatment after drawing, the zinc liquid temperature is 460°C, and the galvanizing time is 70s; the galvanized steel wire is drawn again through a wire drawing machine, and the compression rate is selected to be 80-90%, and the steel wire is stabilized after galvanizing to obtain the galvanized steel wire 301.

[0034] Step 2, preparation of brass-plated steel wire: pickling the selected carbon steel, drying after pickling, passing the carbon steel through a wire drawing machine after drying, drawing it into a steel wire of a predetermined diameter, copper-plating and galvanizing in turn, and then performing heat diffusion treatment, and then the steel wire is pickled with phosphoric acid to obtain the brass-plated steel wire 302.

[0035] Step 3, preparation of sisal-polyester double-covered yarn: using 1100D-1300D high-strength industrial polyester filament as the first polyester filament, using 1300D-1500D high-strength industrial polyester filament as the second polyester filament, and weaving sisal fiber into sisal yarn; first feeding the first polyester filament so that it is coated on the outer surface of the sisal yarn to obtain a first coating layer, and then feeding the second polyester filament so that it is coated on the first coating layer to obtain a second coating layer, thereby obtaining the sisal-polyester double-covered yarn 5, and the sisal-polyester double-covered yarn 5 is treated with oil.

[0036] Step 4, preparation of sisal-modified polyvinyl alcohol single-coated yarn: sisal fiber is woven into sisal yarn, modified polyvinyl alcohol is wet-spun and then subjected to heat stretching treatment to obtain modified polyvinyl alcohol filaments, the modified polyvinyl alcohol filaments are fed into the sisal yarn surface to be coated to obtain the sisal-modified polyvinyl alcohol single-coated yarn 4, and the sisal-modified polyvinyl alcohol single-coated yarn 4 is treated by oil immersion.

[0037] Step 5, preparation of inner layer strands: 7 galvanized steel wires 301 and 6 brass-plated steel wires 302 are taken, one of which is a galvanized steel wire 301 as a core wire, and the 6 brass-plated steel wires 302 are placed in a stranding machine to spirally wrap and twist the core wire, and the other 6 galvanized steel wires 301 are then spirally wrapped and twisted with the core wire and the brass-plated steel wire 302 by the stranding machine to obtain a composite steel wire core strand 3, wherein each brass-plated steel wire 302 is located between the core wire and two adjacent galvanized steel wires 301 in the outer layer. Another 4 composite steel wire core strands 3 are prepared in the same way, and 4 composite steel wire core strands 3 and 4 sisal-polyester double-coated yarns 5 are arranged at intervals, and another composite steel wire core strand 3 is spirally wrapped and twisted by a stranding machine, and then a number of sisal-modified polyvinyl alcohol single-coated yarns 4 are taken and spirally wrapped and twisted until an inner layer strand 1 of a predetermined diameter is formed. It should be noted that rope cores with different diameters can be produced by controlling the number of twisted sisal-modified polyvinyl alcohol single-coated yarns according to different needs, and the diameter of the composite steel wire core strands can also be changed to achieve changes.

[0038] Step 6: Preparation of outer strands: Take a number of sisal-polyester double-covered yarns 5 and use a twisting machine to spirally wrap the inner strands 1 to obtain the high-strength composite rope core.

[0039] Wherein, the modified polyvinyl alcohol comprises the following preparation steps:

[0040] Step 4.1: Weigh polyvinyl alcohol, cellulose nanofibers and graphene oxide according to proportion;

[0041] Step 4.2: Fully stir and disperse the cellulose nanofibers, graphene oxide and water, add polyvinyl alcohol, heat the solution to 90° C. and continue stirring for 4 hours to completely dissolve the polyvinyl alcohol, and then let it stand to defoam to obtain the modified polyvinyl alcohol.

[0042] In step 4, when wet spinning the modified polyvinyl alcohol, a coagulation solution containing 5% by mass of calcium chloride and cooled methanol is used. The solution of the modified polyvinyl alcohol is injected into the flowing coagulation solution through a spinning syringe. The formed fiber filaments are dried and then soaked in methanol solution for 12 h again, taken out, dried in an oven and then subjected to hot stretching treatment.

[0043] The breaking resistance of the 10 mm high-strength composite rope core prepared by the above method reaches 100 KN - 120 KN, the oil content is as high as 25% - 35%, and the flexibility is good.

[0044] In the present invention, a rope core with a composite structure including an inner strand and an outer strand is provided. The inner strand is composed of a composite steel wire core strand, a sisal-polyester double-coated yarn and a sisal-modified polyvinyl alcohol single-coated yarn combined in a specific structure. The outer strand uses a sisal-modified polyvinyl alcohol single-coated yarn. The combination of sisal yarn and different synthetic fiber filaments improves the oil content effect and flexibility of the rope core, and also improves the tensile capacity of the rope core. The composite steel wire core strand combines galvanized steel wire and brass-plated steel wire, which further improves the strength of the rope core and also enhances the supporting force of the rope core. The performance of the rope core is excellent, and the steel wire rope prepared with this rope core can also greatly improve the overall performance of the steel wire rope. The present invention also provides a method for preparing the high-strength composite rope core. The method is simple and easy to operate and has strong applicability.

[0045] The present invention has been described in detail in combination with the embodiments. In addition, it should be noted that, in the above specific embodiments, the various specific technical features described can be combined and changed in any suitable way without contradiction. The present invention will not further describe various possible combination methods. In addition, other variations and combinations according to the various technical features of the present invention should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A high-strength composite rope core, comprising an inner strand and an outer strand, characterized in that: The inner layer strands include 5 composite steel wire core strands, 4 sisal-polyester double-coated yarns, and several sisal-modified polyvinyl alcohol single-coated yarns. Among them, 4 composite steel wire core strands are helically wrapped around another composite steel wire core strand. The sisal-polyester double-coated yarns are arranged between three adjacent composite steel wire core strands, and the sisal-modified polyvinyl alcohol single-coated yarns are filled between the composite steel wire core strands, sisal-polyester double-coated yarns, and the outer layer strands. The composite steel wire core strand includes 7 galvanized steel wires and 6 brass-plated steel wires. Among them, 6 galvanized steel wires are helically wrapped around another galvanized steel wire, and the brass-plated steel wires are arranged in the gaps between three adjacent galvanized steel wires. The outer layer strands include several sisal-polyester double-coated yarns, and the sisal-polyester double-coated yarns are helically wrapped around the inner layer strands.

2. The high-strength composite rope core according to claim 1, characterized in that: The sisal-polyester double-coated yarn includes a first sisal yarn, a first polyester filament, and a second polyester filament. Its preparation method is to first feed the first polyester filament to coat the first sisal yarn to obtain a first coating layer, and then feed the second polyester filament to coat the outer layer of the first coating layer to obtain a second coating layer.

3. The high-strength composite rope core according to claim 1, characterized in that: The sisal-modified polyvinyl alcohol single-coated yarn includes a second sisal yarn and a modified polyvinyl alcohol filament. The sisal-modified polyvinyl alcohol single-coated yarn is prepared by feeding the modified polyvinyl alcohol filament to coat the outer layer of the second sisal yarn.

4. The high-strength composite rope core according to claim 3, characterized in that: The modified polyvinyl alcohol filament is spun from polyvinyl alcohol modified by cellulose nanofibers and graphene oxide.

5. The high-strength composite rope core according to claim 4, characterized in that: The mass ratio of polyvinyl alcohol, cellulose nanofibers, and graphene oxide is 100:6:

1.

6. The high-strength composite rope core according to claim 1, characterized in that: Phosphatize the outer surface of the galvanized steel wire to form a phosphate coating on the surface of the galvanized steel wire, and the coating weight of the phosphate coating is 10 g / m 2. .

7. A preparation method of a high-strength composite rope core for preparing the high-strength composite rope core according to any one of claims 1 to 6, characterized in that, It includes the following steps: Step 1, Preparation of galvanized steel wires: The selected carbon steel is pickled, dried after pickling, and then passed through a wire drawing machine after drying to draw the carbon steel into steel wires with a predetermined diameter. The number of drawing passes is 7 - 10 passes. The temperature of the steel wire during the drawing process does not exceed 300 °C. After drawing, the steel wire is subjected to zinc dipping heat treatment. The temperature of the zinc solution is 460 °C, and the galvanizing time is 70 s. The galvanized steel wire after galvanizing treatment is redrawn through a wire drawing machine, and the compression ratio is selected to be 80 - 90%. After galvanizing, the steel wire is subjected to stabilization treatment to obtain the galvanized steel wire. Step 2, Preparation of brass-plated steel wires: The selected carbon steel is pickled, dried after pickling, and then passed through a wire drawing machine after drying to draw the carbon steel into steel wires with a predetermined diameter. After copper plating and galvanizing in sequence, heat diffusion treatment is carried out, and then the steel wire is treated by phosphoric acid pickling to obtain the brass-plated steel wire. Step 3, Preparation of sisal-polyester double-coated yarns: Use high-strength industrial polyester filaments of 1100D - 1300D as the first polyester filament and high-strength industrial polyester filaments of 1300D - 1500D as the second polyester filament. The sisal fibers are woven into sisal yarns. First, feed the first polyester filament to coat the outer surface of the sisal yarn to obtain a first coating layer, and then feed the second polyester filament to coat the first coating layer to obtain a second coating layer, thereby obtaining the sisal-polyester double-coated yarn. Step 4. Sisal-modified polyvinyl alcohol single-coated yarn: Take sisal fibers and spin them into sisal yarn. After wet spinning the modified polyvinyl alcohol and then performing hot stretching treatment, obtain modified polyvinyl alcohol filaments. Feed the modified polyvinyl alcohol filaments to coat the surface of the sisal yarn to obtain the sisal-modified polyvinyl alcohol single-coated yarn; Step 5. Preparation of the inner layer strands: Take 7 galvanized steel wires and 6 brass-plated steel wires. Using 1 galvanized steel wire as the core wire, place the 6 brass-plated steel wires into a stranding machine to helically wrap the core wire. Then, helically wrap the other 6 galvanized steel wires around the core wire and the brass-plated steel wires to obtain a composite steel wire core strand, where each brass-plated steel wire is located between the core wire and two adjacent outer galvanized steel wires; Prepare another 4 composite steel wire core strands in the same way. Interleave 4 of the composite steel wire core strands and 4 sisal-polyester double-coated yarns, helically wrap them around another composite steel wire core strand using a stranding machine, and then take several sisal-modified polyvinyl alcohol single-coated yarns to continue helically wrapping until an inner layer strand with a predetermined diameter is formed; Step 6: Preparation of the outer layer strands: Take several sisal-polyester double-coated yarns and helically wrap them around the inner layer strand using a stranding machine to obtain the high-strength composite rope core.

8. The preparation method of a high-strength composite rope core according to claim 7, characterized in that: The preparation steps of the modified polyvinyl alcohol are as follows: Step 4.1: Weigh polyvinyl alcohol, cellulose nanofibers, and graphene oxide in proportion; Step 4.2: Thoroughly stir and disperse the cellulose nanofibers, graphene oxide, and water, add polyvinyl alcohol, heat the solution to 90 °C, continuously stir for 4 h until the polyvinyl alcohol is completely dissolved, and then let it stand to defoam to obtain the modified polyvinyl alcohol.

9. The preparation method of a high-strength composite rope core according to claim 7, characterized in that: When performing wet spinning of the modified polyvinyl alcohol in Step 4, use a coagulation solution containing 5% by mass of calcium chloride in methanol. Inject the solution of the modified polyvinyl alcohol into the flowing coagulation solution through a spinning syringe. After the formed fiber filaments are dried, soak them in methanol solution for 12 h again, take them out, dry them in an oven, and then perform hot stretching treatment.

10. The preparation method of a high-strength composite rope core according to claim 7, characterized in that: Perform oil immersion treatment on the sisal-polyester double-coated yarn obtained in Step 3 and the sisal-modified polyvinyl alcohol single-coated yarn obtained in Step 4.

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