A slow-bonding steel strand triggered by tension for physical hybrid curing and a method for preparing the same

Abstract

This invention discloses a slow-bonding steel strand with physical mixing-triggered curing and its preparation method, belonging to the field of prestressed construction. The steel strand includes bare steel strand, an outer sheath, an axially tearable separator membrane placed between the two, a highly thixotropic matrix paste and a thixotropic curing paste filled in the first and second chambers on both sides of the separator membrane. During preparation, the steel strand is treated by a straightening and dust removal mechanism, then the separator membrane is wrapped by a half-segment separator membrane wrapping and forming machine, and then the two pastes are filled separately by a dual-chamber filling pumping module mechanism. Afterwards, the outer sheath is wrapped by a PE sleeve extrusion mechanism, then cooled and shaped in a cooling water tank, and finally wound into a coil by a traction and winding mechanism. During tensioning, the axial displacement of the bare steel strand causes the separator membrane to tear, allowing the two pastes to come into contact, mix, and cure. This invention provides controllable curing time, avoids material waste caused by long-term storage and hardening, and simplifies construction operations.

Description

Technical Field

[0001] This invention relates to the field of prestressed construction technology, specifically to a slow-bonding steel strand that undergoes physical mixing and curing triggered by tension, and its preparation method. Background Technology

[0002] Delayed-bonding prestressing technology is a novel prestressing process that falls between bonded and unbonded prestressing. It combines the advantages of simple and feasible construction of unbonded prestressed structures with the excellent force transmission mechanism of bonded prestressed structures. With the increasing scale of large-scale infrastructure projects such as airport terminals, stadiums, bridges, and roads in China, the application of delayed-bonding prestressing technology is also gradually increasing. Delayed-bonding prestressed steel strands typically consist of prestressed steel strands, a delay-bonding agent layer coated around the strands, and a PE protective sheath covering the delay-bonding agent layer. Before tensioning, the delay-bonding agent is fluid, allowing the steel strands to slide freely within the delay-bonding agent layer, making construction as simple as "unbonded prestressing." After tensioning, the delay-bonding agent gradually solidifies, bonding the steel strands to the sheath as a single unit, and establishing an effective bond with the concrete through the transverse and longitudinal ribs on the sheath surface.

[0003] Current delayed-bonding prestressing technology primarily achieves bonding through the natural curing of a single-component delaying agent within the steel strands. This single-component delaying agent typically consists of epoxy resin and a latent curing agent, which slowly hardens over time at room temperature through a chemical reaction. However, this natural curing method has significant technical drawbacks: the curing time is difficult to control precisely, the pot life of the delaying agent (typically 180 days, 270 days, 360 days, 720 days, etc.) is limited, and once the storage period is exceeded, the entire batch of material becomes unusable due to the hardening of the delaying agent, resulting in severe material waste. Furthermore, if the delaying agent has partially hardened before tensioning, it will significantly increase the tensioning resistance, leading to prestress loss and affecting structural safety.

[0004] To address the aforementioned issues, existing technologies have proposed various active intervention curing schemes. One type of scheme accelerates the curing of the adhesive through heating, such as energizing the steel strands, using heat-conducting wires, or employing electromagnetic powder heating. While these heating measures can shorten the curing cycle to some extent, they still have several shortcomings in practical engineering applications: the heating temperature is difficult to control precisely; excessively high temperatures can easily lead to softening, deformation, or even damage to the PE sheath, while excessively low temperatures result in unsatisfactory curing effects; the heating elements in curved steel strands exhibit uneven resistance distribution along their entire length, leading to inconsistent curing degrees along the strand's length; additional power supply equipment and temperature control systems are required, resulting in complex on-site operation and high energy consumption.

[0005] Another approach employs a two-component mixing-triggered curing method. For example, invention patent CN119122289A discloses a method for actively controlling the hardening time of slow-bonding steel strands and a steel strand pre-embedded component. This approach features a coaxially nested double-cavity structure: a first cavity (inner layer) holds the curing agent, and a second cavity (outer layer surrounding the first cavity) holds the slow-bonding agent. After the steel strand is embedded in the concrete structure and tensioned, rotating components located at both ends of the curing agent holding tube rotate the two ends of the tube in opposite directions, causing the curing agent to flow from the first cavity into the second cavity and mix with the slow-bonding agent. However, this scheme is clearly not reasonable or feasible in actual engineering: the steel strand is a flexible component. After being placed in the steel reinforcement cage and concrete is poured, the overall linear shape is stressed, presents a curved state, and has a large length. The rotation operation at both ends cannot be effectively transmitted to the entire length; the torque transmission loss along the steel strand is severe, and the hardener holding tube in the middle section is difficult to break; the hardener only mixes with the slow binder in local areas at both ends, and the slow binder in most areas in the middle fails to come into contact with the hardener, making it impossible to achieve uniform curing along the entire length.

[0006] It is evident that existing slow-bonding steel strands still suffer from the following technical defects in curing control: (1) the curing time of natural curing schemes is uncontrollable, and the limited storage period leads to material waste; (2) the heating intervention scheme is difficult to operate, temperature control is challenging, and energy consumption is high; (3) existing two-component mixing schemes are not feasible for flexible long components and cannot achieve uniform mixing along the entire length. Therefore, there is an urgent need for a slow-bonding steel strand and its preparation method that can actively and reliably control the curing timing of the slow bond during prestressed tensioning construction. Summary of the Invention

[0007] Purpose of the Invention: The purpose of this invention is to address the shortcomings of existing technologies by providing a slow-bonding steel strand that undergoes physical mixing and curing triggered by tension, and its preparation method. This invention aims to solve the problems of uncontrollable curing time and material waste caused by long-term storage and hardening of existing slow-bonding steel strands. It also addresses the difficulties in implementing existing technologies that use heating steel strands, heating wires, electromagnetic powder, etc., for auxiliary hardening, as well as the lack of engineering feasibility and inability to achieve uniform mixing along the entire length of existing two-component mixing schemes on flexible long components.

[0008] Technical solution: The present invention provides a slow-bonding steel strand that cures through physical mixing, comprising a bare steel strand and an outer sheath covering the bare steel strand, and further comprising an axially tearable isolation membrane disposed between the bare steel strand and the outer sheath, the axially tearable isolation membrane extending longitudinally along the bare steel strand and dividing the circumferential space of the bare steel strand into a first chamber and a second chamber that are independent of each other; The first chamber is filled with a first paste, and the second chamber is filled with a second paste; The axially tearable separator is configured such that when the bare steel strand is subjected to tension and undergoes axial displacement, the bare steel strand and the first and second pastes slide axially relative to the outer sheath, applying an axial shear force to the separator; at the same time, due to the inclination of the axis of the bare steel strand, a radial extrusion force is applied to the separator, and the separator tears under the combined action of the axial shear force and the radial extrusion force, allowing the first paste and the second paste to come into contact and mix and solidify.

[0009] Furthermore, the axially tearable separator is made of low-density polyethylene film with a thickness of 0.08mm to 0.12mm.

[0010] Furthermore, the longitudinal edges of the axially tearable separator abut against the inner wall of the outer sheath to form a circumferential constraint on the separator during tensioning.

[0011] Furthermore, the first paste is a highly thixotropic matrix paste, which is an epoxy resin-based paste material.

[0012] Furthermore, the second paste is a thixotropic curing paste that is compatible with the first paste, and the thixotropic curing paste is an amine curing agent paste material.

[0013] Furthermore, the outer sheath is made of high-density polyethylene and is formed by heat-sealing and extrusion.

[0014] A method for preparing a slow-bonding steel strand that cures through physical mixing includes the following steps: S1: Place the bare steel strand on the wire rope unwinding machine for unwinding; S2: The unwound steel strand enters the straightening and dust removal mechanism, and the straightening, surface rust removal and high-pressure dust removal cleaning treatment are completed through the straightening and dust removal unit and the dust removal and rust removal unit. S3: The processed steel strand enters the half-segmented separator film coating forming machine. The half-segmented separator film coating forming machine includes a separator film coating die head, a die head support, and a die head base. The separator film coating die head includes a coating die head chamber, an arc-shaped drag ring type separator injection machine, a rectangular separator film heating forming machine, a soft wheel support shaft, and a silicone soft wheel. The steel strand is stably positioned by the middle arc-shaped drag ring mechanism of the arc-shaped drag ring type separator injection machine. The upper and lower separator film injection machines simultaneously inject PE separator film and lubricant. Then, the upper and lower rectangular heating plates of the rectangular separator film heating forming machine heat and level the separator film, dividing the single steel strand longitudinally into two open chambers that are not connected to each other. S4: The formed steel strands roll laterally through the silicone soft wheels to assist in leveling the isolation membrane structure; S5: The steel strand with the separated cavity covered by the isolation membrane travels to the dual-cavity filling pumping module mechanism. The dual-cavity filling pumping module mechanism includes a module mechanism base, a thixotropic curing paste storage unit, a high thixotropic matrix paste storage unit, a paste power delivery pipeline, and a dual-cavity filling die head. The stirring devices built into the thixotropic curing paste storage unit and the high thixotropic matrix paste storage unit uniformly stir and pump the two types of pastes respectively. The two types of pastes are transported to the dual-cavity filling die head through independent paste power delivery pipelines. The vertical isolation ribs of the dual-cavity filling die head divide the filling die head chamber into a thixotropic curing paste chamber and a high thixotropic matrix paste chamber, which are respectively filled into the left and right cavities of the steel strand. S6: After the paste filling is completed, the steel strand enters the PE sleeve extrusion mechanism. The main extrusion body and extrusion die of the PE sleeve extrusion mechanism uniformly extrude the molten PE plastic and cover the outside of the steel strand to form an outer sheath. S7: Steel strands with PE sheaths enter the cooling water tank and are cooled and shaped by circulating water. S8: The finished steel strand after shaping is drawn and transported at a constant speed by the traction wheel set of the traction winding mechanism and wound into a coil.

[0015] Furthermore, in step S3, in the diaphragm covering die head of the split-section diaphragm covering molding machine, the middle arc-shaped drag ring mechanism of the arc-shaped drag ring diaphragm injection machine stably positions the steel strand, and the upper and lower diaphragm injection machines are respectively supplied by the rolled PE diaphragm built into the cavities on both sides of the die head support.

[0016] Furthermore, in step S5, in the dual-cavity filling pumping module mechanism, the thixotropic curing paste storage unit and the high thixotropic matrix paste storage unit are respectively fixed on the module mechanism base, and each storage unit has a hollow structure inside and is equipped with a stirring device.

[0017] Furthermore, in step S5, the filling mold head chamber of the dual-cavity filling mold head is composed of seamless steel pipe welded together. The filling mold head interface is inserted into the filling mold head chamber to form an injection port and is connected to the paste power delivery pipeline. A gap is reserved inside the vertical isolation rib, and the isolation membrane passes through the gap.

[0018] Beneficial effects: Compared with the prior art, the advantages of the present invention are as follows: 1. This invention physically separates the high thixotropic matrix paste and the thixotropic curing paste through an axially tearable separator. The two pastes do not come into contact with each other during storage and do not undergo a curing reaction. This effectively solves the problem of limited storage period and premature scrapping caused by natural hardening of traditional single-component slow-bonding steel strands, and significantly extends the product's shelf life.

[0019] 2. This invention utilizes the prestressing tensioning process itself as a curing trigger. During tensioning, the axial displacement of the bare steel strand causes the release membrane to tear uniformly along the longitudinal direction, and the two-component paste immediately mixes and begins the curing reaction. Compared to the passive waiting of natural curing methods, this invention achieves active control of the curing timing.

[0020] 3. This invention requires no auxiliary means such as heating steel strands, heating wires, or electromagnetic powder, and does not rely on external power input, thus avoiding the defects of difficult heating and temperature control, and simplifying on-site construction operations. Compared with the unreasonable solution in CN119122289A that requires rotating the two ends of the flexible long component after tensioning, this invention utilizes the tensioning process itself as a trigger, without adding extra construction operations, making it practically feasible in engineering.

[0021] 4. In this invention, the axially tearable separator 203 is made of low-density polyethylene film with a thickness of 0.08mm to 0.12mm, which extends continuously along the entire length of the steel strand. During tensioning, the separator ruptures uniformly along the longitudinal direction under the action of compression and shearing, so that the two pastes are mixed synchronously along the entire length of the steel strand, overcoming the uneven mixing defect caused by point rupture in the discrete capsule type scheme.

[0022] 5. In this invention, the curing shrinkage rate of the high thixotropic matrix paste 204 and the thixotropic curing paste 205 after mixing is less than 0.8%, and the compressive strength reaches more than 30MPa, which can meet the design requirements of prestressed structures for the mechanical properties of the adhesive after curing.

[0023] 6. The preparation method provided by the present invention forms a continuous production line by means of a wire rope unwinding machine, a straightening and dust removal mechanism, a half-separated isolation film coating forming machine, a double-cavity filling pumping module mechanism, a PE sleeve extrusion mechanism, a cooling water tank and a traction winding mechanism. It realizes the integrated production of online forming of isolation film, synchronous filling of two components and continuous sheath coating. The process is reliable and efficient. Attached Figure Description

[0024] Figure 1 This is a production process diagram of the slow-bonding steel strand that is cured by physical mixing as described in this invention; Figure 2 This is a structural composition diagram of the physically mixed and triggered curing slow-bonding steel strand described in this invention; Figure 3 This is a schematic diagram of the structure of the half-segment separation film coating molding machine described in this invention; Figure 4 This is a schematic diagram of the structure of the diaphragm covering die head described in this invention; Figure 5 This is a schematic diagram of the dual-cavity filling pump module mechanism of the present invention; Figure 6 This is a schematic diagram of the dual-cavity filling mold head structure described in this invention.

[0025] In the diagram, 1. Wire rope unwinding machine; 2. Steel strand with a split structure; 201. Bare steel strand; 202. PE plastic sheath; 203. Axially tearable separator; 204. High thixotropic matrix paste; 205. Thixotropic curing paste; 3. Straightening and dust removal mechanism; 4. Split separator membrane coating molding machine; 401. Diaphragm coating die; 4011. Coating die housing; 4012. Arc-shaped drag ring type diaphragm injection machine; 4013. Rectangular diaphragm heating molding machine; 4014. Flexible roller support shaft; 4015. Silicone flexible roller; 4 02. Die head support; 403. Die head base; 5. Dual-cavity filling pump module mechanism; 501. Module mechanism base; 502. Thixotropic curing paste storage unit; 503. High thixotropic matrix paste storage unit; 504. Paste power delivery pipeline; 505. Dual-cavity filling die head; 5051. Filling die head chamber; 5052. Filling die head interface; 5053. Vertical isolation rib; 5054. Thixotropic curing paste chamber; 5055. High thixotropic matrix paste chamber; 6. PE sleeve extrusion mechanism; 7. Cooling water tank; 8. Traction and winding mechanism. Detailed Implementation

[0026] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the embodiments described.

[0027] Example 1: Slow-bonding steel strand like Figure 2 As shown, this embodiment provides a slow-bonding steel strand with a half-splitting structure that is cured by physical mixing, including bare steel strand 201, axially tearable release film 203, high thixotropic matrix paste 204, thixotropic curing paste 205 and PE plastic sheath 202.

[0028] The bare steel strand 201 is composed of multiple high-strength steel wires twisted together, and any number of strands can be used. In this embodiment, a 7-strand steel wire twisting method is used. An axially tearable release film 203 covers the outer circumferential surface of the bare steel strand 201. This release film 203 extends longitudinally along the bare steel strand 201, and its longitudinal edges abut against the inner wall of a PE plastic sheath 202. The PE plastic sheath 202 is formed using a hot-melt extrusion process. During extrusion, the high temperature of the molten PE material creates a hot-melt connection effect on the edges of the low-density polyethylene release film 203, causing a partial circumferential connection between the longitudinal edges of the release film 203 and the inner wall of the PE plastic sheath 202, thus strengthening the bond between the release film 203 and the PE plastic sheath 202 to a certain extent. The release film 203 also divides the circumferential space of the bare steel strand 201 into two independent chambers.

[0029] The first chamber is filled with a high-thixotropic matrix paste 204, and the second chamber is filled with a thixotropic curing paste 205. A PE plastic sheath 202, made primarily of high-density polyethylene, is heat-sealed and extruded over the outside of the release membrane 203.

[0030] The axially tearable separator 203 is made of low-density polyethylene material and has a thickness of 0.08mm to 0.12mm.

[0031] The first paste 204 is a highly thixotropic matrix paste, which can be made of epoxy resin-based paste materials disclosed in the prior art, such as paste-like putty with modified epoxy resin as the matrix. This paste has no flowability when at rest, exhibits high thixotropy, does not self-cure when stored alone, and its viscosity does not change drastically.

[0032] The second paste 205 is a thixotropic curing paste, which can be a curing agent paste material disclosed in the prior art that is compatible with the above-mentioned base paste, such as a paste material with a modified amine curing agent as the curing component. This paste has no flowability when at rest, has high thixotropy, does not self-cur when stored alone, has no drastic change in viscosity, and can solidify and solidify after being mixed with the first paste 204. The curing shrinkage rate is <0.8%, and the compressive strength reaches more than 30 MPa.

[0033] PE plastic sheath 202 is a protective sheath formed on the outside of steel strands through heat sealing and extrusion, with high-density polyethylene as the main material.

[0034] In this embodiment, during storage and transportation, the high thixotropic matrix paste 204 and the thixotropic curing paste 205 are physically separated by an axially tearable release liner 203, preventing them from contacting each other and thus preventing a curing reaction. During on-site tensioning, the axial displacement of the bare steel strand 201 causes the release liner 203 to tear under stress, resulting in a cross-linking curing reaction after the two pastes mix.

[0035] During on-site construction, the slow-bonding steel strands are laid within the reinforcing steel skeleton of the concrete structure according to design requirements. After positioning and fixing, concrete is poured. Once the concrete reaches its design strength, the steel strands are prestressed. During tensioning, the bare steel strands 201 undergo axial displacement, causing the release membrane 203 to tear uniformly along the longitudinal direction through compression and shearing. After the release membrane 203 tears, the high-thixotropic matrix paste 204 and the thixotropic curing paste 205 come into contact and mix. The two pastes undergo a cross-linking curing reaction, with a curing shrinkage rate of less than 0.8% and a compressive strength exceeding 30 MPa, achieving active controlled curing of the slow-bonding steel strands.

[0036] Example 2: Preparation method of slow-bonding steel strand like Figure 1As shown, the production process of the slow-bonding steel strand that is physically mixed and triggered to cure is as follows: the wire rope unwinding machine 1 releases the bare steel strand, which is then processed by the straightening and dust removal mechanism 3 and enters the half-segmented isolation film coating forming machine 4 to complete the isolation film coating and cavitation. Then it enters the double-cavity filling pumping module mechanism 5 to complete the double-cavity paste filling. Subsequently, it passes through the PE sleeve extrusion mechanism 6 to complete the outer sheath extrusion coating, and then passes through the cooling water tank 7 to cool and shape. Finally, it passes through the traction winding machine.

[0037] This embodiment provides a method for preparing a slow-bonding steel strand that is cured by physical mixing, including the following steps: S1: Unwinding procedure.

[0038] The bare steel strand is placed on the wire rope unwinding machine 1 for unwinding. The wire rope unwinding machine 1 carries the bare steel strand and achieves continuous and uniform unwinding of the wire rope.

[0039] S2: Calibration, straightening, and dust removal steps.

[0040] After unwinding, the steel strand enters the straightening and dust removal mechanism 3. The straightening and dust removal mechanism 3 consists of a straightening unit, a dust removal and rust removal unit, and a support and transmission module. The straightening unit straightens the coiled steel strand to eliminate plastic bending deformation; the dust removal and rust removal unit uses high-pressure airflow in conjunction with a wire brush to remove surface rust, oil, and dust impurities from the steel strand.

[0041] S3: Separator film coating and forming step.

[0042] The processed steel strands enter the half-splitting separator film coating forming machine 4. For example... Figure 3 As shown, the semi-segmented separator film coating forming machine 4 includes a separator film coating die head 401, a die head support 402, and a die head base 403. The die head base 403 is connected to the die head support 402 and is used to support the overall device. The die head support 402 supports the separator film coating die head 401, with rolled PE separator films placed inside the cavities on both sides, and is connected to the arc-shaped drag ring type separator film injection machine 4012. The top is integrally formed with the die head base 403.

[0043] like Figure 4 As shown, the diaphragm coating die head 401 includes a coating die head chamber 4011, an arc-shaped drag ring type diaphragm injection machine 4012, a rectangular diaphragm heating and forming machine 4013, a flexible wheel support shaft 4014, and a silicone flexible wheel 4015. The coating die head chamber 4011 is composed of an integral steel plate welded together.

[0044] After the steel strand enters the diaphragm covering die head 401, the middle arc-shaped drag ring mechanism of the arc-shaped drag ring diaphragm injection machine 4012 stably positions the steel strand. The upper and lower diaphragm injection machines simultaneously inject the rolled PE diaphragm and matching lubricant built into the cavities on both sides of the die head support 402 onto the surface of the steel strand. The lubricant can be a grease-based material, which mainly has a lubricating effect on the membrane.

[0045] Subsequently, the steel strands coated with PE diaphragms enter the rectangular diaphragm thermoforming machine 4013. The upper and lower rectangular heating plates of the rectangular diaphragm thermoforming machine 4013 heat the PE diaphragm raw materials. The heating time varies depending on the material. For example, LLDPE is heated at a temperature of 110-125℃ with a heating time of 0.5-2 seconds, which longitudinally divides a single steel strand into two unconnected open chambers.

[0046] S4: Leveling step.

[0047] The formed steel strands pass through silicone flexible rollers 4015. A roller support shaft 4014 passes through the silicone flexible rollers 4015 and connects to the covering mold head chamber 4011. The silicone flexible rollers 4015 roll laterally, assisting in leveling and conveying the formed separator membrane structure, ensuring the separator membrane structure is not damaged during transport.

[0048] S5: Paste filling step.

[0049] The steel strands that have completed the separation membrane covering and cavitating process proceed to the dual-cavity filling pumping module mechanism 5. For example... Figure 5 As shown, the dual-cavity filling pumping module mechanism 5 includes a module mechanism base 501, a thixotropic curing paste storage unit 502, a high thixotropic matrix paste storage unit 503, a paste power delivery pipeline 504, and a dual-cavity filling die head 505.

[0050] The module base 501 supports the upper overall structure. The thixotropic curing paste storage unit 502 and the high thixotropic matrix paste storage unit 503 are respectively fixed on the module base 501. Each storage unit has a hollow structure and is equipped with a stirring device to uniformly stir and pump the thixotropic curing paste and the high thixotropic matrix paste inside. The stirring speed is 10-40 rpm and can be adjusted according to the paste viscosity. The pumping pressure is 0.8-1.5 MPa, and the flow rate is linked to the production line speed for control. It is equipped with a dual-pump synchronous-pressure closed-loop-flow monitoring control mode.

[0051] The two types of pastes are transported to the dual-cavity filling die head 505 via independent paste power delivery pipes 504. For example... Figure 6As shown, the dual-cavity filling mold 505 includes a filling mold chamber 5051, a filling mold interface 5052, a vertical isolation rib 5053, a thixotropic curing paste chamber 5054, and a high thixotropic matrix paste chamber 5055. The filling mold chamber 5051 is constructed from seamless welded steel pipes and is connected to the filling mold interface 5052. The filling mold interface 5052 penetrates the filling mold chamber 5051 to form an injection port and is connected to the paste power delivery pipeline 504. The vertical isolation rib 5053 is connected to the filling mold chamber 5051 and has a pre-reserved gap through which the isolation membrane 203 passes. The vertical isolation rib 5053 divides the filling mold chamber 5051 into two independent chambers: the thixotropic curing paste chamber 5054 and the high thixotropic matrix paste chamber 5055.

[0052] The high-thixotropic matrix paste 204 enters the high-thixotropic matrix paste chamber 5055 via a paste power delivery pipe 504 and a corresponding filling die interface 5052, and is injected into the left chamber of the steel strand. The thixotropic curing paste 205 enters the thixotropic curing paste chamber 5054 via another paste power delivery pipe 504 and a corresponding filling die interface 5052. Under the physical separation of the vertical isolation ribs 5053, the two pastes are respectively filled into the left and right chambers of the steel strand. The optimal fit gap between the vertical isolation ribs and the isolation membrane is about 0.2mm, which is precisely adjusted according to the thickness of the isolation membrane, the characteristics of the paste, and the production line speed.

[0053] S6: Sheath extrusion step.

[0054] After the paste filling is completed, the steel strand enters the PE sleeve extrusion mechanism 6. The PE sleeve extrusion mechanism 6 consists of an extrusion main body and an extrusion die. The extrusion main body heats the high-density polyethylene raw material to a molten state, and the extrusion temperature is controlled in stages from 140℃ to 210℃, while the melt temperature is controlled from 190℃ to 200℃. The extrusion die uniformly extrudes the molten PE plastic and completely covers the outside of the steel strand to form an outer sheath (202). The sheath thickness is controlled from 1.0mm to 1.5mm, and the extrusion speed is controlled from 10m / min to 30m / min, synchronized with the production line speed.

[0055] S7: Cooling and shaping step.

[0056] The steel strand with a PE sheath enters the cooling water tank 7. The cooling water tank 7 consists of the tank body, a supporting and positioning structure, and a circulating temperature control system. The circulating water rapidly cools the steel strand, ensuring the PE sheath is fully cooled and shaped, and the structure is stabilized. The steel strand travels at a uniform speed in the cooling water tank at a production line speed (10m / min), and the circulating water rapidly cools it, ensuring the PE sheath is fully cooled and shaped, and the structure is stabilized. The residence time of the steel strand in the cooling water tank is calculated based on the ratio of the effective cooling length of the tank to the travel speed, i.e., residence time = effective cooling length of the tank ÷ travel speed; taking a production line speed of 10m / min and an effective cooling length of 10m as an example, the residence time of the steel strand in the cooling water tank is 60s.

[0057] S8: Traction and winding steps.

[0058] The finished steel strands, after being shaped, are conveyed at a uniform speed by the traction and winding mechanism 8. The traction and winding mechanism 8 consists of a traction wheel set, a power and speed regulation unit, and wire pressing and positioning components. The linear speed of the traction wheel of the traction and winding mechanism 8 serves as the main speed reference for the entire line, and the steel strand unwinding machine 1 acts as a driven following unit to achieve synchronous control of the production line speed.

[0059] The winding device is driven by a torque motor, and an automatic roll diameter compensation system maintains constant winding tension. A floating tension detection roller with a built-in tension sensor collects the wire harness tension value in real time before winding. The PLC control system, combined with a meter encoder, calculates the real-time roll outer diameter. As the roll outer diameter increases, the output torque of the torque motor is automatically reduced, achieving closed-loop tension control. Tension fluctuations are kept within ±15N throughout the entire process. When the tension exceeds the set threshold, the system automatically reduces speed and issues an audible and visual alarm.

[0060] Through the above control, the cooled, slowly bonded steel strands are pulled, fed, and neatly wound into coils.

[0061] Mechanical structure used in the preparation method of Example 3 3.1 Semi-partitioned separator film coating and forming machine like Figure 3 and Figure 4 As shown, the semi-segmented separator film coating forming machine 4 includes a separator film coating die head 401, a die head support 402, and a die head base 403.

[0062] The die head base 403 is fixedly installed on the mounting plane of the production line to support the overall device. The lower end of the die head bracket 402 is fixedly connected to the die head base 403, and the upper part of the die head bracket 402 supports the diaphragm covering the die head 401. Rolls of PE diaphragm raw materials are placed inside the cavities on both sides of the die head bracket 402. The two cavities are respectively connected to the upper and lower sections of the arc-shaped drag ring type diaphragm injection machine 4012, providing a continuous supply of raw materials for diaphragm injection.

[0063] The diaphragm covering die head 401 includes a covering die head chamber 4011, an arc-shaped drag ring type diaphragm injection machine 4012, a rectangular diaphragm heating and forming machine 4013, a soft wheel support shaft 4014, and a silicone soft wheel 4015.

[0064] The coating die head chamber 4011 is constructed from a single welded steel plate, with an internal channel running along the direction of the steel strand's travel for the strand to pass through. The arc-shaped drag ring diaphragm injection machine 4012 is installed at the front section inside the coating die head chamber 4011, consisting of a central arc-shaped drag ring mechanism and upper and lower diaphragm injection machines. The central arc-shaped drag ring mechanism is arc-shaped, encircling the outer circumference of the steel strand, providing stable positioning and ensuring the strand's shape remains unchanged. The upper and lower diaphragm injection machines are respectively positioned above and below the steel strand, injecting the built-in PE diaphragms and lubricant onto the upper and lower surfaces of the steel strand, causing the PE diaphragm to cover the strand longitudinally and dividing the circumferential space of the steel strand into two symmetrical semi-cylindrical chambers.

[0065] The rectangular diaphragm thermoforming machine 4013 is installed at the rear of the covering die head chamber 4011, adjacent to the arc-shaped drag ring type diaphragm injection machine 4012. The rectangular diaphragm thermoforming machine 4013 consists of upper and lower rectangular heating plates, which are positioned opposite each other, with the spacing between them matching the overall outer diameter of the steel strand and the covering diaphragm. The upper and lower rectangular heating plates heat, level, and solidify the PE diaphragm raw material output from the arc-shaped drag ring type diaphragm injection machine 4012, causing the PE diaphragm to form a stable longitudinal separation structure on the surface of the steel strand.

[0066] The flexible roller support shaft 4014 passes through the silicone flexible roller 4015 and is connected to the rear end of the covering mold head chamber 4011. The silicone flexible roller 4015 is located at the outlet end of the covering mold head chamber 4011 and can roll laterally around the flexible roller support shaft 4014. When the steel strand exits from the covering mold head chamber 4011, the silicone flexible roller 4015 rolls in contact with the surface of the steel strand covered with the release liner, assisting in leveling the formed release liner structure and ensuring that the release liner structure is not damaged.

[0067] 3.2 Dual-cavity filling pump module mechanism like Figure 5 and Figure 6 As shown, the dual-cavity filling pumping module mechanism 5 includes a module mechanism base 501, a thixotropic curing paste storage unit 502, a high thixotropic matrix paste storage unit 503, a paste power delivery pipeline 504, and a dual-cavity filling die head 505.

[0068] The module mechanism base 501 is fixedly installed on the installation plane of the production line, located downstream of the half-separation film covering and forming machine 4, and is used to support the upper overall structure.

[0069] A thixotropic curing paste storage unit 502 is fixedly installed on one side of the module mechanism base 501. It has a hollow interior and is used to store the thixotropic curing paste 205. The storage unit is equipped with a stirring device to uniformly agitate the thixotropic curing paste, preventing sedimentation or segregation during storage and pumping. The storage unit is also equipped with a pumping device to output the paste at a set pressure.

[0070] The high thixotropic matrix paste storage unit 503 is fixedly installed on the other side of the module mechanism base 501. It has a hollow internal structure and is used to store the high thixotropic matrix paste 204. The storage unit is equipped with a stirring device, which can uniformly stir and pump the high thixotropic matrix paste inside.

[0071] The paste delivery pipeline 504 includes two independent delivery lines. One line connects the contact-deformation curing paste storage unit 502 to the corresponding injection port of the dual-cavity filling die 505, and the other line connects the high-thixotropic matrix paste storage unit 503 to the corresponding injection port of the dual-cavity filling die 505. The two lines are independent of each other to ensure that the two pastes do not mix during delivery.

[0072] The dual-cavity filling die head 505 is installed at the upstream end of the module mechanism base 501 and connected to the paste power delivery pipeline 504. The dual-cavity filling die head 505 includes a filling die head chamber 5051, a filling die head interface 5052, a vertical isolation rib 5053, a thixotropic curing paste chamber 5054, and a high thixotropic matrix paste chamber 5055.

[0073] The filling die head chamber 5051 is composed of seamless steel pipe welded together, with a through channel inside along the direction of the steel strand travel for the steel strand carrying the isolation membrane to pass through. The filling die head interface 5052 is located on the side wall of the filling die head chamber 5051, penetrates into the interior of the filling die head chamber 5051 to form an injection port, and is connected to the end of the paste power delivery pipeline 504.

[0074] The vertical isolation rib 5053 is a longitudinally arranged partition structure, fixedly connected to the inner wall of the filling mold head chamber 5051. The vertical isolation rib 5053 divides the internal space of the filling mold head chamber 5051 into two independent chambers: a thixotropic curing paste chamber 5054 and a high thixotropic matrix paste chamber 5055. A gap is reserved inside the vertical isolation rib 5053 to ensure that the isolation membrane passes through the gap without being crushed or damaged when the steel strand carrying the isolation membrane passes through it.

[0075] The thixotropic curing paste chamber 5054 is located on one side of the vertical isolation rib 5053 and is connected to a paste power delivery pipe 504 via a filling die interface 5052. It receives the thixotropic curing paste 205 and injects the paste into one chamber of the steel strand. The high thixotropic matrix paste chamber 5055 is located on the other side of the vertical isolation rib 5053 and is connected to another paste power delivery pipe 504 via a filling die interface 5052. It receives the high thixotropic matrix paste 204 and injects the paste into another chamber of the steel strand.

[0076] When the steel strand carrying the pre-formed separator membrane passes through the double-cavity filling die 505, the two independent chambers simultaneously inject the corresponding paste into the left and right chambers of the steel strand. Under the physical separation of the vertical isolation ribs 5053, the two pastes remain independent of each other and do not mix during the filling process.

[0077] As described above, although the invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the invention itself. Various changes in form and detail may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A slow-bonding steel strand cured by physical mixing, comprising bare steel strand (201) and an outer sheath (202) covering the outside of the bare steel strand, characterized in that: It also includes an axially tearable isolation membrane (203) disposed between the bare steel strand (201) and the outer sheath (202), the axially tearable isolation membrane (203) extending longitudinally along the bare steel strand (201) and dividing the circumferential space of the bare steel strand (201) into a first chamber and a second chamber that are independent of each other; The first chamber is filled with a first paste (204), and the second chamber is filled with a second paste (205). The axially tearable release membrane (203) satisfies the requirement that when the bare steel strand (201) is subjected to tension and undergoes axial displacement, the release membrane (203) allows the first paste (204) to come into contact with and mix with the second paste (205) and solidify.

2. The slow-bonding steel strand according to claim 1, characterized in that: The axially tearable isolation membrane (203) is made of low-density polyethylene film with a thickness of 0.08mm to 0.12mm.

3. The slow-bonding steel strand according to claim 1, characterized in that: The longitudinal sides of the axially tearable isolation membrane (203) abut against the inner wall of the outer sheath (202) to form a circumferential constraint on the isolation membrane during tensioning.

4. The slow-bonding steel strand according to claim 1, characterized in that: The first paste (204) is a highly thixotropic matrix paste, which is an epoxy resin matrix paste material.

5. The slow-bonding steel strand according to claim 1, characterized in that: The second paste (205) is a thixotropic curing paste that is matched with the first paste (204). The thixotropic curing paste is an amine curing agent paste material.

6. The slow-bonding steel strand according to claim 1, characterized in that: The outer sheath (202) is made of high-density polyethylene and is formed by heat-sealing extrusion.

7. A method for preparing a slow-bonding steel strand that cures through physical mixing, characterized in that, Includes the following steps: S1: Place the bare steel strand on the wire rope unwinding machine (1) for unwinding; S2: The unwound steel strand enters the straightening and dust removal mechanism (3), and the straightening, surface rust removal and high-pressure dust removal and cleaning treatment are completed by the straightening and dust removal unit and the dust removal and rust removal unit. S3: The processed steel strand enters the half-segmented isolation film coating forming machine (4). The half-segmented isolation film coating forming machine (4) includes a diaphragm coating die head (401), a die head support (402), and a die head base (403). The diaphragm coating die head (401) includes a coating die head chamber (4011), an arc-shaped drag ring type diaphragm injection machine (4012), a rectangular diaphragm heating forming machine (4013), a soft wheel support shaft (4014), and a silicone soft wheel (4015). The steel strand is stably positioned by the middle arc-shaped drag ring mechanism of the arc-shaped drag ring type diaphragm injection machine (4012). The upper and lower diaphragm injection machines simultaneously inject PE diaphragm and lubricant. Then, the upper and lower rectangular heating plates of the rectangular diaphragm heating forming machine (4013) heat and flatten the diaphragm, dividing the single steel strand longitudinally into two open chambers that are not connected to each other. S4: The formed steel strands are rolled laterally by the silicone soft wheel (4015) to assist in leveling the isolation membrane structure; S5: The steel strand that has completed the separation film covering the cavity moves to the dual-cavity filling pumping module (5). The dual-cavity filling pumping module (5) includes a module base (501), a thixotropic curing paste storage unit (502), a high thixotropic matrix paste storage unit (503), a paste power delivery pipeline (504), and a dual-cavity filling die head (505). The stirring devices built into the thixotropic curing paste storage unit (502) and the high thixotropic matrix paste storage unit (503) uniformly stir and pump the two types of paste. The two types of paste are transported to the dual-cavity filling die head (505) through independent paste power delivery pipelines (504). The vertical isolation ribs (5053) of the dual-cavity filling die head (505) divide the filling die head chamber into a thixotropic curing paste chamber (5054) and a high thixotropic matrix paste chamber (5055), which are respectively filled into the left and right cavities of the steel strand. S6: After the paste filling is completed, the steel strand enters the PE sleeve extrusion mechanism (6). The main body of the PE sleeve extrusion mechanism (6) and the extrusion die head will uniformly extrude the molten PE plastic and cover the outside of the steel strand to form an outer sheath (202). S7: The steel strand with PE sheath enters the cooling water tank (7) and is cooled and shaped by the circulating water. S8: The finished steel strand after shaping is pulled and transported at a constant speed by the traction wheel group of the traction winding mechanism (8) and wound into a coil.

8. The preparation method according to claim 7, characterized in that: In step S3, in the diaphragm covering die head (401) of the half-separated diaphragm covering forming machine (4), the middle arc-shaped drag ring mechanism of the arc-shaped drag ring diaphragm injection machine (4012) stabilizes the steel strand, and the upper and lower diaphragm injection machines are respectively supplied by the rolled PE diaphragm built into the cavities on both sides of the die head support (402).

9. The preparation method according to claim 7, characterized in that: In step S5, in the dual-cavity filling pumping module mechanism (5), the thixotropic curing paste storage unit (502) and the high thixotropic matrix paste storage unit (503) are respectively fixed on the module mechanism base (501). Each storage unit has a hollow structure and is equipped with a stirring device.

10. The preparation method according to claim 7, characterized in that: In step S5, the filling mold head chamber (5051) of the dual-cavity filling mold head (505) is made of seamless steel pipe welded together. The filling mold head interface (5052) is inserted into the filling mold head chamber (5051) to form an injection port and is connected to the paste power delivery pipeline (504). A gap is reserved inside the vertical isolation rib (5053) and the isolation membrane (203) passes through the gap.

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