A compactly structured composite core and a method for producing the same

Abstract

The application provides a compact composite core and a preparation method thereof. A plurality of composite fiber strands containing a second steel core, an elastic buffer fiber bundle and a high-strength fiber bundle are arranged on the outer circumferential side of a first steel core to form a composite fiber layer, and a filler wire is arranged in the outer gap between adjacent composite fiber strands. The overall carrying capacity of the core is further improved, the core has excellent elastic buffer performance and flexibility, impact load can be effectively absorbed and stress can be dispersed. Meanwhile, the first thermosetting resin layer and the second thermosetting resin layer can form radial constraint and shaping support for the internal structure of the core, effectively prevent the core from being loose and dislocated, improve the supporting performance of the core, and protect the internal structure of the core to prolong the service life. Finally, a steel wire strand layer is arranged between the first thermosetting resin layer and the second thermosetting resin layer, so that the tensile strength and torsional resistance of the core are significantly improved.

Description

Technical Field

[0001] This invention relates to the field of wire rope technology, specifically to a compact composite rope core and its preparation method. Background Technology

[0002] Composite core is the core component of high-performance wire rope. Its structural design and material properties directly determine the overall load-bearing capacity, flexibility, fatigue resistance and service life of the wire rope.

[0003] In heavy-load conditions such as elevator traction, mine hoisting, port loading and unloading, construction machinery, and bridge cables, steel wire ropes need to withstand frequent tensile, bending, torsion and alternating impact loads, and are exposed to harsh environments such as dust, humidity, salt spray and corrosive media for a long time. This places extremely stringent requirements on the structural compactness, tensile strength, shock absorption performance, torsional performance and corrosion resistance of the rope core.

[0004] While ordinary fiber rope cores offer good flexibility, their low tensile strength makes them prone to permanent compressive deformation under long-term stress. This leads to a reduction in wire rope diameter, a looser structure, and uneven inter-strand pressure, accelerating internal wire wear and breakage, resulting in a shorter service life. Ordinary steel core ropes, while possessing high tensile strength, suffer from poor flexibility, insufficient shock absorption, and a low bending fatigue life. Under frequent bending conditions, they are prone to early wire breakage and have poor torsional resistance, easily leading to kinking and loosening of strands. Existing composite rope cores generally suffer from insufficient structural compactness, weak interlayer bonding, and easy delamination. Internal gaps easily accumulate impurities and moisture, accelerating internal corrosion and wear. Furthermore, poor stress matching between the fiber layer and the steel wire strand layer easily leads to stress concentration, causing premature breakage of the rope core at weak points. These issues prevent them from meeting the long-term stable use requirements of high-performance steel wire ropes under heavy loads and harsh conditions.

[0005] Therefore, it is necessary to provide a composite rope core with a compact structure to solve the problems of loose structure, insufficient comprehensive performance and short service life of composite rope cores in the prior art. Summary of the Invention

[0006] In view of the need for high strength and long service life in existing steel wire ropes, the present invention provides a composite rope core with a compact structure and a method for manufacturing the same.

[0007] A tightly structured composite rope core includes a first steel core and a composite fiber layer, a first thermosetting resin layer, a steel wire strand layer, and a second thermosetting resin layer sequentially wrapped around the first steel core. The composite fiber layer includes several composite fiber strands spirally twisted around the outer surface of the first steel core, with a reinforcing steel wire positioned between the external gaps of adjacent composite fiber strands. Each composite fiber strand includes a second steel core and several composite fiber bundles spirally twisted around the second steel core. Each composite fiber bundle includes an elastic cushioning fiber bundle and several high-strength fiber bundles spirally twisted around the elastic cushioning fiber bundle. Both the first and second thermosetting resin layers are made of modified polyurethane resin. A first fiber mesh is wrapped around the outside of the first thermosetting resin layer. The steel wire strand layer includes several outer steel wires spirally compacted and twisted around the outer periphery of the first fiber mesh. A second fiber mesh is wrapped around the outer periphery of each steel wire strand layer, and the second thermosetting resin is disposed on the outer periphery of the second fiber mesh. The first steel core, reinforcing steel wire, second steel core, and outer steel wire are all made of stainless steel wire.

[0008] Preferably, the elastic fiber bundle is a polyurethane elastic fiber bundle, and the high-strength fiber bundle is spun from a mixture of aramid fiber filaments, ultra-high molecular weight polyethylene fiber filaments and modified carbon fiber filaments in a mass percentage ratio of 5:3:2.

[0009] Preferably, the first fiber mesh and the second fiber mesh are both one of glass fiber mesh, ultra-high molecular weight polyethylene fiber mesh or basalt fiber mesh.

[0010] Preferably, the modified polyurethane resin is composed of a polyurethane matrix, a low-viscosity epoxy resin modifier, nano-calcium carbonate filler, a polyolefin elastomer toughening agent, a silane coupling agent, functional additives, and zinc stearate.

[0011] Preferably, the twist direction of the composite fiber strand is opposite to that of the outer steel wire.

[0012] Preferably, the diameter of the first steel core cross-section is 2.5 to 3 times the diameter of the composite fiber strand cross-section, and the diameter of the first steel core cross-section is 2 to 3 times the diameter of the outer steel wire cross-section.

[0013] This invention also provides a method for preparing a tightly structured composite rope core, comprising the following steps: Step S1: Select duplex stainless steel wire rod, perform heat treatment, pickling, and phosphating in sequence, and then continuously draw it through several passes to obtain stainless steel wire with a cross-sectional diameter of 1-4 mm; Step S2: Select stainless steel wire with the corresponding cross-sectional diameter as the first steel core, reinforcing steel wire, second steel core, and outer steel wire; Step S3: After loosening and straightening the elastic buffer fibers, arrange them parallel along the axial direction and twist them with low twist to form an elastic buffer fiber bundle; then, with the elastic buffer fiber bundle as the center, evenly spirally twist several high-strength fiber bundles around the outside of the elastic buffer fiber bundle in the circumferential direction, and perform pre-tensioning treatment to obtain a composite fiber bundle; Step S4: Arrange the second steel core and several composite fiber bundles with a splitter, deform them through a pre-deformer, guide them to the same converging point, and then twist them to obtain a composite fiber strand; then arrange the first steel core, several composite fiber strands, and several filler wires with a splitter, and perform pre-deformation... Step S5: The pre-prepared modified polyurethane resin is added to the extruder, and the initial rope strand is continuously extruded and coated through the extruder head of the extruder, so that a first thermosetting resin layer is formed on the outside of the rope strand; Step S6: After the first thermosetting resin layer is extruded and output, a first fiber mesh is spirally wrapped around the outer periphery of the first thermosetting resin layer, and the first fiber mesh is thermally bonded and fixed by hot pressing to obtain an intermediate rope strand; Step S7: The intermediate rope strand and several outer steel wires are arranged with a splitter, deformed by a pre-deformer, introduced to the same joining point, twisted into a strand, and then spirally wrapped around the outer periphery with a second fiber mesh to obtain the initial rope core; Step S8: The initial rope core is continuously extruded and coated through the extruder head of the extruder, so that a second thermosetting resin layer is formed on the outside of the initial rope core to obtain the composite rope core.

[0014] Preferably, in step S3, the method for preparing the high-strength fiber bundle is as follows: S31, select carbon fiber filaments, place them in acetone solution for 24 hours, wash the carbon fiber thoroughly with anhydrous ethanol solution 3 to 5 times, and then dry them at 60 to 80°C for 4 to 6 hours; S32, immerse the dried carbon fiber filaments in concentrated nitric acid for 2-3 hours for surface acidification, then wash them thoroughly with deionized water until the pH of the washing solution is 7, and then dry them at 80°C to obtain acidified carbon fiber filaments; S33, select silane coupling agents KH-550 and KH-560, and compound them at a mass ratio of 1:1, then add anhydrous ethanol and deionized water at a volume ratio of 4:1 to prepare a compound silane coupling agent solution with a mass concentration of 2%-3%, then place the acidified carbon fiber filaments in the compound silane coupling agent solution and perform ultrasonic treatment at 70°C. S34. After 0.8 hours, modified carbon fiber filaments are obtained; S35. Aramid fiber filaments, ultra-high molecular weight polyethylene fiber filaments, and the modified carbon fiber filaments are weighed out in a mass percentage ratio of 5:3:2, and then an antistatic agent is sprayed onto the surface of the weighed fiber filaments and left to stand for 8-12 hours; S36. The three pretreated fiber filaments are fed into a cotton blending machine for uniform mixing. After mixing, the fibers are fed into a cotton opener for opening and impurity removal; S37. The opened fiber filaments are fed into a cotton cleaning device for more fine opening. Then, they enter the carding process to obtain a raw sliver, which is then drawn into a finished sliver. The finished sliver is then drawn and twisted into a fine yarn on a yarn machine. The yarn is then fed into a twisting machine for low-twist twisting treatment and pre-tensioned under a tension control of 0.1-0.3 cN / dtex to obtain the high-strength fiber bundle.

[0015] Preferably, the preparation process of the modified polyurethane resin is as follows: Step S51, select the following by mass percentage: 55%–57% polyurethane matrix, 18%–20% low-viscosity epoxy resin modifier, 6%–10% nano-calcium carbonate filler, 4%–8% polyolefin elastomer toughening agent, 0.8%–1.2% silane coupling agent, 2%–4.5% functional additives, and 0.5% zinc stearate; S52, add 60% of the selected silane coupling agent to the nano-calcium carbonate filler and place it in a high-speed mixer, stirring for 15–20 min at 80–90°C and 500–600 r / min to complete the surface modification, and cool to room temperature for later use; at the same time, preheat the polyurethane matrix in a constant temperature environment of 40–50°C for 30 min; S53, put the preheated polyurethane matrix and low-viscosity epoxy resin modifier into a reaction vessel, raise the temperature to 85–95°C, and stir at 300–400 r / min. Stir at 00 r / min for 30-40 min to ensure full fusion and grafting reaction; S54, add pretreated nano-calcium carbonate filler and polyolefin elastomer toughening agent to the reactor in sequence, keep the temperature constant, and continue stirring for 20-25 min to ensure uniform dispersion of filler and toughening agent in matrix; S55, add the remaining 40% of silane coupling agent, zinc stearate and functional additives to the reactor, cool to 60-70℃, and stir for 15-20 min; simultaneously turn on the ultrasonic homogenizer and ultrasonically treat with 300-400W power for 10-15 min to eliminate air bubbles and ensure uniform mixing of components; S56, feed the uniformly mixed modified polyurethane resin melt into a twin-screw extruder, control the extrusion temperature at 170-190℃ and the extrusion speed at 180-220 r / min for continuous granulation to obtain modified polyurethane resin granules.

[0016] Preferably, the thickness of the first thermosetting resin layer is 0.5 mm, and the thickness of the second thermosetting resin layer is 0.8 mm.

[0017] The beneficial effects of this invention are as follows: This invention provides a tightly structured composite rope core, with a first steel core as the central load-bearing matrix. A composite fiber layer is formed on the outer periphery of the first steel core by a plurality of composite fiber strands comprising a second steel core, elastic buffer fiber bundles, and high-strength fiber bundles. Filler steel wires are placed in the outer gaps between adjacent composite fiber strands, further enhancing the overall load-bearing capacity of the rope core while endowing it with excellent elastic buffering performance and flexibility, effectively absorbing impact loads and dispersing stress. Simultaneously, the first and second thermosetting resin layers provide radial constraint and shaping support for the internal structure of the rope core, effectively preventing loosening and misalignment, improving the support performance of the rope core, and protecting the internal structure, thus extending its service life. Finally, the addition of a steel wire strand layer between the first and second thermosetting resin layers significantly improves the tensile strength and torsional resistance of the rope core.

[0018] In addition, by setting a fiber mesh on the outer side of the second thermosetting resin layer, wear and damage to the inner and outer sides of the first thermosetting resin layer, the second thermosetting resin layer and the steel wire strand layer are effectively avoided; at the same time, the fiber mesh can increase the interfacial friction between the first thermosetting resin layer, the second thermosetting resin layer and the steel wire strand layer, effectively suppressing the circumferential and radial misalignment and slippage of the steel wire strand layer under the reciprocating load, and further improving the compactness of the rope core structure.

[0019] The present invention also provides a method for preparing a composite rope core with a compact structure, which makes the composite rope core have the characteristics of compact structure, high tensile and torsional strength, and is not easy to disperse, so that it can be used in a variety of working conditions and has a long service life. Attached Figure Description

[0020] Figure 1 A schematic diagram of a tightly structured composite rope core provided by the present invention; Figure 2 This is a schematic diagram of a method for preparing a tightly structured composite rope core, as provided by the present invention. Attached Figure Labels

[0021] 1. First steel core; 2. Composite fiber layer; 21. Composite fiber strand; 211. Second steel core; 212. Composite fiber bundle; 3. First thermosetting resin layer; 4. Steel wire strand layer; 41. Outer steel wire; 5. Second thermosetting resin layer; 6. Reinforcing steel wire; 7. First fiber web; 8. Second fiber web. Detailed Implementation

[0022] The embodiments described below are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0023] refer to Figure 1 As shown, a tightly structured composite rope core includes a first steel core 1 and a composite fiber layer 2, a first thermosetting resin layer 3, a steel wire strand layer 4, and a second thermosetting resin layer 5 sequentially wrapped around the first steel core 1.

[0024] The first steel core 1 serves as the central component of the rope core, providing a stable covering foundation for the outer structure. This ensures that the outer structures can be arranged in an orderly manner around it, while also providing rigid support for the rope core and bearing the load.

[0025] Specifically, the composite fiber layer 2 includes a plurality of composite fiber strands 21 spirally twisted around the outer surface of the first steel core 1, and a reinforcing steel wire 6 is provided in the external gap between adjacent composite fiber strands 21.

[0026] The reinforcing steel wire 6 can fill the gaps between the composite fiber strands 21, improve the structural density and support of the rope core, make the rope core more evenly stressed during use, and avoid structural damage caused by local stress concentration.

[0027] The composite fiber strand 21 includes a second steel core 211 and a plurality of composite fiber bundles 212 spirally twisted around the second steel core 211.

[0028] The second steel core 211 provides rigid support for the composite fiber bundle. The spiral twisting method ensures a tight bond between the composite fiber bundle and the second steel core 211, preventing tensile breakage and loosening when the composite fiber bundle 212 is subjected to stress alone. Furthermore, the composite structure of the steel core and the composite fiber bundle allows the composite fiber strands 21 to possess both sufficient strength to assist in load-bearing and good flexibility to adapt to bending and winding conditions of the rope core, thereby improving the rope core's applicability and service life.

[0029] In this embodiment, the composite fiber bundle 212 includes an elastic buffer fiber bundle and several high-strength fiber bundles spirally twisted around the elastic buffer fiber bundle.

[0030] The elastic fiber bundle is a polyurethane elastic fiber bundle, and the high-strength fiber bundle is spun from a mixture of aramid fiber filaments, ultra-high molecular weight polyethylene fiber filaments and modified carbon fiber filaments in a mass percentage ratio of 5:3:2.

[0031] Polyurethane elastic fiber bundles possess excellent elasticity, toughness, and abrasion resistance, effectively providing cushioning and shock absorption. They also exhibit good chemical stability and are not prone to aging. High-strength fiber bundles are spun from three types of fiber filaments: aramid fiber filaments provide high tensile strength and heat resistance, modified carbon fiber filaments enhance rigidity and corrosion resistance, and ultra-high molecular weight polyethylene fiber filaments improve abrasion resistance and toughness. This blended spinning process gives the high-strength fiber bundles excellent mechanical properties, while also being lightweight and high-strength. This allows for increased load-bearing capacity of the rope core while reducing its overall weight, and simultaneously ensuring a compact fiber bundle structure, providing support for the overall tightness of the rope core.

[0032] Both the first thermosetting resin layer 3 and the second thermosetting resin layer 5 are made of modified polyurethane resin.

[0033] Specifically, by setting the first thermosetting resin layer 3 and the second thermosetting resin layer 5, radial constraint and shaping support can be formed on the internal structure of the rope core, effectively preventing the rope core from becoming loose and misaligned, and improving the support performance of the rope core.

[0034] Meanwhile, taking advantage of the excellent adhesion and fluidity of modified polyurethane resin, when the first thermosetting resin layer 3 and the second thermosetting resin layer 5 are set, the molten modified polyurethane resin can penetrate into the inter-strand gaps of the composite fiber strand 21 and the steel wire strand layer 4. After curing, each strand is tightly bonded to the first thermosetting resin layer 3 and the second thermosetting resin layer 5 into a tightly structured whole, which significantly improves the structural density and integrity of the rope core and effectively avoids the problem of slippage or loosening of each strand of the rope core during long-term use.

[0035] In addition, modified polyurethane resin has excellent wear resistance, corrosion resistance and aging resistance. The protective layer it forms can effectively isolate external moisture, dust and corrosive media, protect the internal structure of the rope core, and its good toughness can adapt to the bending deformation of the rope core, avoid structural loosening caused by resin layer cracking, and balance protection and structural tightness, thereby extending the service life of the rope core.

[0036] In this embodiment, the modified polyurethane resin is composed of a polyurethane matrix, a low-viscosity epoxy resin modifier, nano-calcium carbonate filler, a polyolefin elastomer toughening agent, a silane coupling agent, functional additives, and zinc stearate.

[0037] Low-viscosity epoxy resin modifiers and zinc stearate improve the flowability of modified polyurethane resin, facilitating its penetration into the interstrand gaps and curing to bond the strands during the coating process to form a thermosetting resin layer. Nano-calcium carbonate filler fills the fine pores within the modified polyurethane resin, increasing its density and reducing shrinkage, preventing shrinkage voids after curing into a thermosetting resin layer. Polyolefin elastomer toughening agents enhance the toughness of the thermosetting resin layer, preventing it from becoming brittle due to excessive rigidity and avoiding voids that could disrupt the tight core structure. Silane coupling agents strengthen the bond between the resin and adjacent strands, ensuring a tight fit. Functional additives specifically optimize the processing and performance of the modified polyurethane resin, improving its curing rate and molding effect.

[0038] The first thermosetting resin layer 3 is wrapped with a first fiber mesh 7; the steel wire strand layer 4 includes a plurality of outer steel wires 41 spirally compacted and twisted around the outer periphery of the first fiber mesh 7. The steel wire strand layer 4 is wrapped with a second fiber mesh 8, and the second thermosetting resin layer 5 is disposed around the outer periphery of the second fiber mesh 8.

[0039] In this embodiment, the first fiber mesh 7 is one of glass fiber mesh, ultra-high molecular weight polyethylene fiber mesh, or basalt fiber mesh.

[0040] Both the first fiber mesh 7 and the second fiber mesh 8 can act as a transition buffer, effectively preventing wear and damage to the inner and outer surfaces of the first thermosetting resin layer 3, the second thermosetting resin layer 5, and the steel wire strand layer 4. At the same time, the first fiber mesh 7 and the second fiber mesh 8 can increase the interfacial friction between the first thermosetting resin layer 3, the second thermosetting resin layer 5, and the steel wire strand layer 4, effectively suppressing circumferential and radial misalignment and slippage of the steel wire strand layer 4 under reciprocating load, improving the bonding stability between the steel wire strand layer 4 and the inner structure, and ensuring the structural integrity and stability of the rope core during long-term torsion and bending operations.

[0041] In this embodiment, the twist direction of the composite fiber strand 21 is opposite to that of the outer steel wire 41. The reverse twisting method can effectively counteract the twisting stress of the composite fiber strand 21 and the outer steel wire 41, preventing the rope core from loosening and deforming during the stress process, and improving the overall structural stability of the rope core.

[0042] In this embodiment, the cross-sectional diameter of the first steel core 1 is 2.5 to 3 times the cross-sectional diameter of the composite fiber strand 21, and the cross-sectional diameter of the first steel core 1 is 2 to 3 times the cross-sectional diameter of the outer steel wire 41. This cross-sectional diameter setting helps ensure that the first steel core 1 has sufficient rigid support within the rope core, and makes the structure compact after the strands are twisted together. This helps to achieve an optimized match between mechanical properties and structural compactness, improving the overall structural stability and load-bearing capacity of the rope core.

[0043] In this embodiment, the first steel core 1, the reinforcing steel wire 6, the second steel core 211, and the outer steel wire 41 are all made of stainless steel wire, which makes the rope core highly corrosion resistant, strong, and long-lasting.

[0044] refer to Figure 1 and Figure 2 As shown, the present invention also provides a method for preparing a tightly structured composite rope core, comprising the following steps: Step S1: Select duplex stainless steel wire rod, perform heat treatment, pickling, and phosphating in sequence, and then draw it through several passes to obtain stainless steel wire with a cross-sectional diameter of 1-4 mm.

[0045] Step S2: Select stainless steel wires with corresponding cross-sectional diameters as the first steel core 1, reinforcing steel wire 6, second steel core 211, and outer steel wire 41.

[0046] Step S3: After the elastic buffer fibers are opened and straightened, they are arranged parallel along the axial direction and twisted at a low twist to form an elastic buffer fiber bundle; then, with the elastic buffer fiber bundle as the center, several high-strength fiber bundles are evenly spirally twisted around the outside of the elastic buffer fiber bundle and pre-tensioned to obtain a composite fiber bundle 212.

[0047] The method for preparing the high-strength fiber bundle 212 is as follows: Step S31: Select carbon fiber filaments, place them in acetone solution for 24 hours, wash them thoroughly with anhydrous ethanol solution 3 to 5 times, and then dry them at 60 to 80°C for 4 to 6 hours.

[0048] Step S32: Immerse the dried carbon fiber filaments in concentrated nitric acid for 2-3 hours to acidify the surface. Then wash thoroughly with deionized water until the pH of the washing solution is 7, and dry at 80°C to obtain acidified carbon fiber filaments.

[0049] Step S33: Select silane coupling agents KH-550 and KH-560 and compound them at a mass ratio of 1:1. Then add anhydrous ethanol and deionized water at a volume ratio of 4:1 to prepare a compound silane coupling agent solution with a mass concentration of 2%-3%. Then place the acidified carbon fiber filament in the compound silane coupling agent solution and perform ultrasonic treatment at 70°C for 0.8h to obtain modified carbon fiber filament.

[0050] The modified carbon fibers obtained after acidification and compounding with silane coupling agents have significantly improved interfacial compatibility when blended with aramid fibers and ultra-high molecular weight polyethylene fibers. The fibers are more tightly bound together during blending, effectively avoiding delamination and peeling in subsequent blending, and significantly improving the overall internal structure of the high-strength fiber bundles.

[0051] Step S34: Weigh out aramid fiber, ultra-high molecular weight polyethylene fiber, and modified carbon fiber in a mass percentage ratio of 5:3:2 respectively. Then spray antistatic agent on the surface of the weighed fiber and let it stand for 8-12 hours.

[0052] Allowing the antistatic agent to stand for 8-12 hours allows it to spread evenly on the fiber surface, penetrate and absorb, forming a stable antistatic protective layer. This solves the problems of static adsorption, entanglement, flyaways and breakage caused by high-speed friction in subsequent processes such as blending, opening, carding and twisting of microfiber filaments.

[0053] Step S35: The three types of pretreated fibers are fed into a cotton blending machine for uniform mixing. After the fibers are mixed, they are fed into a cotton opener for opening and impurity removal.

[0054] Step S36: The opened fiber filaments are fed into the opening and cleaning equipment. After the fiber filaments are opened more finely, they enter the carding process to obtain the raw sliver. After the raw sliver is drawn, it is then drawn and twisted into fine yarn on the yarn machine. It is then sent to the twisting machine for low twisting treatment. After pre-tensioning treatment under the condition of tension control at 0.1~0.3cN / dtex, the high-strength fiber bundle is obtained.

[0055] This high-strength fiber bundle preparation method enables the thorough and uniform blending of aramid fibers, ultra-high molecular weight polyethylene fibers, and modified carbon fibers in a specific ratio. This achieves deep synergy and complementarity in the performance of the three fibers, compensating for the shortcomings of individual fibers and enhancing the interfacial compatibility and bonding strength between dissimilar fibers through the use of modified carbon fibers. Consequently, the resulting high-strength fiber bundle possesses comprehensive characteristics such as high strength and modulus, impact and wear resistance, heat and corrosion resistance, dimensional stability, and creep resistance, significantly improving the overall mechanical strength, structural stability, and long-term reliability of the fiber bundle.

[0056] Step S4: Arrange the second steel core 211 and several composite fiber bundles 212 using a splitter, deform them through a pre-deformer, guide them to the same joining point, and then twist them to obtain composite fiber strands 21; then arrange the first steel core 1, several composite fiber strands 2 and several filler wires 6 using a splitter, deform them through a pre-deformer, guide them to the same joining point, and apply oil to twist them to obtain an initial rope strand.

[0057] Step S5: Add the pre-prepared modified polyurethane resin into the extruder, and then allow the initial rope strands to be continuously extruded and coated through the extruder head of the extruder, so that a first thermosetting resin layer 3 is formed on the outside of the rope strands.

[0058] The preparation process of the modified polyurethane resin is as follows: Step S51: Select by mass percentage: 55%–57% polyurethane matrix, 18%–20% low viscosity epoxy resin modifier, 6%–10% nano calcium carbonate filler, 4%–8% polyolefin elastomer toughening agent, 0.8%–1.2% silane coupling agent, 2%–4.5% functional additives, and 0.5% zinc stearate.

[0059] Step S52: Add 60% of the selected silane coupling agent to the nano-calcium carbonate filler and place it in a high-speed mixer. Stir for 15-20 minutes at 80-90℃ and 500-600r / min to complete the surface modification. Cool to room temperature for later use. At the same time, preheat the polyurethane matrix in a constant temperature environment of 40-50℃ for 30 minutes.

[0060] Step S53: Add the preheated polyurethane matrix and low-viscosity epoxy resin modifier into the reactor, heat to 85-95℃, and stir at 300-400 r / min for 30-40 min to ensure full fusion and grafting reaction; Step S53: Add the pretreated nano-calcium carbonate filler and polyolefin elastomer toughening agent to the reactor in sequence, keep the temperature constant, and continue stirring for 20-25 min to ensure uniform dispersion of the filler and toughening agent in the matrix. Step S55: Add the remaining 40% of silane coupling agent, zinc stearate and functional additives to the reactor, cool to 60-70℃, and stir for 15-20 minutes; at the same time, turn on the ultrasonic homogenizer and ultrasonically treat with 300-400W power for 10-15 minutes to eliminate air bubbles in the system and make the components evenly mixed.

[0061] Step S56: Feed the uniformly mixed modified polyurethane resin melt into a twin-screw extruder and continuously granulate by controlling the extrusion temperature at 170-190℃ and the extrusion speed at 180-220r / min to obtain modified polyurethane resin granules.

[0062] The modified polyurethane resin prepared by this method has the characteristics of high strength, excellent thermal stability, and strong interfacial bonding. It also has good fluidity during processing and can be bonded to high-strength fiber bundles and steel wire strands 4. It has strong adhesion and can withstand long-term stress without cracking or falling off. After being made into a thermosetting resin layer, it can significantly improve the overall structural strength and service life of the rope core.

[0063] Step S6: After the first thermosetting resin layer 3 is extruded and output, a first fiber mesh 7 is spirally wrapped around the periphery of the first thermosetting resin layer 3, and the first fiber mesh 3 is thermally bonded and fixed by hot pressing to obtain an intermediate rope strand.

[0064] Step S7: Arrange the intermediate rope strands and several outer steel wires 41 using a splitter, deform them through a pre-deformer, guide them to the same joining point, twist them into strands, and then spirally wrap a second fiber net 8 around the outer periphery to obtain the initial rope core. Step S8: The initial rope core is continuously extruded and coated through the extrusion head of the extruder, so that a second thermosetting resin layer 5 is formed on the outside of the initial rope core, thus obtaining the composite rope core.

[0065] The present invention provides a method for preparing a composite rope core with a compact structure, wherein the composite rope core comprises a first steel core 1 and a composite fiber layer 2, a first thermosetting resin layer 3, a steel wire strand layer 4 and a second thermosetting resin layer 5 sequentially covering the first steel core 1, and has the characteristics of compact structure, high tensile strength, not easy to disperse and long service life.

[0066] In this embodiment, the thickness of the first thermosetting resin layer 3 is 0.5 mm, and the thickness of the second thermosetting resin layer 5 is 0.8 mm.

[0067] The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A composite rope core with a compact structure, characterized in that, It includes a first steel core and a composite fiber layer, a first thermosetting resin layer, a steel wire strand layer and a second thermosetting resin layer sequentially covering the first steel core; The composite fiber layer includes several composite fiber strands spirally twisted around the outer surface of the first steel core, and a reinforcing steel wire is provided in the external gap between adjacent composite fiber strands. The composite fiber strand includes a second steel core and several composite fiber bundles spirally twisted around the second steel core; the composite fiber bundle includes an elastic buffer fiber bundle and several high-strength fiber bundles spirally twisted around the elastic buffer fiber bundle. Both the first thermosetting resin layer and the second thermosetting resin layer are made of modified polyurethane resin; a first fiber mesh is wrapped around the outside of the first thermosetting resin layer; the steel wire strand layer includes a plurality of outer steel wires that are spirally compacted and twisted around the outer periphery of the first fiber mesh; a second fiber mesh is wrapped around the outer periphery of each steel wire strand layer, and the second thermosetting resin is disposed on the outer periphery of the second fiber mesh. The first steel core, the reinforcing steel wire, the second steel core, and the outer steel wire are all made of stainless steel wire.

2. The composite rope core with a compact structure according to claim 1, characterized in that, The elastic fiber bundle is a polyurethane elastic fiber bundle, and the high-strength fiber bundle is spun from a mixture of aramid fiber filaments, ultra-high molecular weight polyethylene fiber filaments and modified carbon fiber filaments in a mass percentage ratio of 5:3:

2.

3. The composite rope core with a compact structure according to claim 1, characterized in that, Both the first fiber mesh and the second fiber mesh are one of glass fiber mesh, ultra-high molecular weight polyethylene fiber mesh or basalt fiber mesh.

4. The composite rope core with a compact structure according to claim 1, characterized in that, The modified polyurethane resin is composed of a polyurethane matrix, a low-viscosity epoxy resin modifier, nano-calcium carbonate filler, a polyolefin elastomer toughening agent, a silane coupling agent, functional additives, and zinc stearate.

5. The composite rope core with a compact structure according to claim 1, characterized in that, The twist direction of the composite fiber strand is opposite to that of the outer steel wire.

6. The composite rope core with a compact structure according to claim 1, characterized in that, The diameter of the first steel core cross section is 2.5 to 3 times the diameter of the composite fiber strand cross section, and the diameter of the first steel core cross section is 2 to 3 times the diameter of the outer steel wire cross section.

7. A method for preparing a tightly structured composite rope core, characterized in that, Includes the following steps: Step S1: Select duplex stainless steel wire rod, perform heat treatment, pickling, and phosphating in sequence, and then draw it through several passes to obtain stainless steel wire with a cross-sectional diameter of 1-4 mm. Step S2: Select stainless steel wires with corresponding cross-sectional diameters as the first steel core, reinforcing steel wire, second steel core, and outer steel wire; Step S3: After the elastic buffer fibers are opened and straightened, they are arranged parallel along the axial direction and twisted at a low twist to form an elastic buffer fiber bundle; then, with the elastic buffer fiber bundle as the center, several high-strength fiber bundles are evenly spirally twisted around the outside of the elastic buffer fiber bundle and pre-tensioned to obtain a composite fiber bundle. Step S4: Arrange the second steel core and several composite fiber bundles using a splitter, deform them through a pre-deformer, guide them to the same joining point, and then twist them to obtain a composite fiber strand; then arrange the first steel core, several composite fiber strands and several filler wires using a splitter, deform them through a pre-deformer, guide them to the same joining point, and apply oil to twist them to obtain an initial rope strand. Step S5: Add the pre-prepared modified polyurethane resin into the extruder, and then let the initial rope strands pass through the extruder head of the extruder for continuous extrusion coating, so that a first thermosetting resin layer is formed on the outside of the rope strands. Step S6: After the first thermosetting resin layer is extruded and output, a first fiber mesh is spirally wrapped around the outer periphery of the first thermosetting resin layer. The first fiber mesh is thermally bonded and fixed by hot pressing to obtain an intermediate rope strand. Step S7: Arrange the intermediate rope strands and several outer steel wires using a splitter, deform them through a pre-deformer, guide them to the same joining point, twist them into strands, and then spirally wrap a second fiber net around the outer periphery to obtain the initial rope core. Step S8: The initial rope core is continuously extruded and coated through the extruder head of the extruder, so that a second thermosetting resin layer is formed on the outside of the initial rope core, thus obtaining the composite rope core.

8. The method for preparing a tightly structured composite rope core according to claim 7, characterized in that, In step S3, the method for preparing the high-strength fiber bundle is as follows: S31. Select carbon fiber filaments and place them in acetone solution for 24 hours. Then, wash the carbon fiber thoroughly with anhydrous ethanol solution 3 to 5 times and dry it at 60 to 80°C for 4 to 6 hours. S32. Immerse the dried carbon fiber filaments in concentrated nitric acid for 2-3 hours to acidify the surface. Then wash thoroughly with deionized water until the pH of the washing solution is 7. Dry at 80°C to obtain acidified carbon fiber filaments. S33. Select silane coupling agents KH-550 and KH-560 and compound them in a mass ratio of 1:

1. Then add anhydrous ethanol and deionized water in a volume ratio of 4:1 to prepare a compound silane coupling agent solution with a mass concentration of 2%-3%. Then place the acidified carbon fiber filament in the compound silane coupling agent solution and sonicate it at 70°C for 0.8h to obtain modified carbon fiber filament. S34. Weigh out aramid fiber, ultra-high molecular weight polyethylene fiber and modified carbon fiber respectively in a mass percentage ratio of 5:3:

2. Then spray antistatic agent on the surface of the weighed fiber and let it stand for 8-12 hours. S35. The three types of pretreated fibers are fed into a cotton blender for uniform mixing. After the fibers are mixed, they are fed into a cotton opener for opening and removing impurities. S36. The opened fiber filaments are fed into the opening equipment for more detailed opening. Then, they enter the carding process to obtain the raw sliver, which is then drawn to obtain the finished sliver. Subsequently, the sliver is drawn and twisted into fine yarn on a yarn machine. Then, it is sent to a twisting machine for low-twist twisting treatment. Finally, it is pre-tensioned under tension control of 0.1 to 0.3 cN / dtex to obtain the high-strength fiber bundle.

9. The method for preparing a tightly structured composite rope core according to claim 7, characterized in that, The preparation process of the modified polyurethane resin is as follows: Step S51: Select the following by mass percentage: 55%–57% polyurethane matrix, 18%–20% low-viscosity epoxy resin modifier, 6%–10% nano-calcium carbonate filler, 4%–8% polyolefin elastomer toughening agent, 0.8%–1.2% silane coupling agent, 2%–4.5% functional additives, and 0.5% zinc stearate; S52. Add 60% of the selected silane coupling agent to the nano-calcium carbonate filler and place it in a high-speed mixer. Stir for 15-20 minutes at 80-90℃ and 500-600r / min to complete the surface modification. Cool to room temperature for later use. At the same time, preheat the polyurethane matrix in a constant temperature environment of 40-50℃ for 30 minutes. S53. Add the preheated polyurethane matrix and low-viscosity epoxy resin modifier into the reactor, heat to 85-95℃, and stir at 300-400r / min for 30-40min to allow the two to fully fuse and undergo a grafting reaction. S54. Add the pretreated nano-calcium carbonate filler and polyolefin elastomer toughening agent to the reactor in sequence, keep the temperature constant, and continue stirring for 20-25 minutes to ensure that the filler and toughening agent are evenly dispersed in the matrix. S55. Add the remaining 40% of silane coupling agent, zinc stearate and functional additives to the reactor, cool to 60-70℃, and stir for 15-20 minutes; at the same time, turn on the ultrasonic homogenizer and ultrasonically treat with 300-400W power for 10-15 minutes to eliminate air bubbles in the system and make the components evenly mixed. S56. The uniformly mixed modified polyurethane resin melt is fed into a twin-screw extruder granulator. The extrusion temperature is controlled at 170-190℃ and the extrusion speed is controlled at 180-220r / min for continuous granulation to obtain modified polyurethane resin granules.

10. The method for preparing a tightly structured composite rope core according to claim 7, characterized in that, The thickness of the first thermosetting resin layer is 0.5 mm, and the thickness of the second thermosetting resin layer is 0.8 mm.

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