Integrally formed synthetic railway sleeper, preparation process and preparation apparatus

Abstract

Provided in the present invention are an integrally formed synthetic railway sleeper, a preparation process and a preparation apparatus. The synthetic railway sleeper comprises: a polyurethane resin matrix, wherein continuous glass fibers are longitudinally arranged in the polyurethane resin matrix for the longitudinal reinforcement of the synthetic railway sleeper, and a reinforcing layer consisting of a glass fiber fabric and a polyurethane resin is arranged on the surface of the polyurethane resin matrix; the thickness of the reinforcing layer is 1-10 mm; and the overall density of the synthetic railway sleeper is 0.64-1.4 g / cm3; the polyurethane resin accounts for 35-50% of the total weight of the synthetic railway sleeper; the continuous glass fibers account for 35-60% of the total weight of the synthetic railway sleeper; and the glass fiber fabric accounts for 3-10% of the total weight of the synthetic railway sleeper. The present application can significantly increase the overall strength of synthetic railway sleepers, avoid transverse cracking, and reduce VOCs generated in the production process of synthetic railway sleepers and solid waste pollution caused by polishing.

Description

An integrally molded synthetic railway sleeper, its manufacturing process and manufacturing apparatus Technical Field

[0001] This invention relates to the field of rail transit technology, and more specifically, to an integrally molded synthetic sleeper, its manufacturing process, and its manufacturing apparatus. Background Technology

[0002] Railway sleepers are crucial components in the rail transit sector, distributing the load from trains evenly to the track bed and playing a vital role in the stable and safe operation of rail transit. Currently, the most widely used railway sleepers globally are wooden sleepers and reinforced concrete sleepers. However, wooden sleepers suffer from problems such as susceptibility to decay and aging, uneven strength, and high water absorption. Reinforced concrete sleepers, on the other hand, have drawbacks including high maintenance costs, short lifespan, poor toughness, heavy weight, difficult installation, and challenges in on-site drilling and fabrication. Therefore, in recent years, new synthetic railway sleepers have been extensively researched worldwide.

[0003] Polyurethane foam synthetic railway sleepers are composite materials formed by glass fiber reinforced polyurethane foam, often simply called synthetic sleepers. They are widely used due to their advantages such as lightweight, high strength, corrosion resistance, insulation, good weather resistance, and high production and installation efficiency. However, existing synthetic sleepers also have drawbacks, such as using unidirectional continuous glass fiber reinforcement without transverse fiber reinforcement, which poses a risk of transverse cracking during use. Furthermore, the production process involves spraying a release agent onto the mold surface to facilitate demolding, followed by surface polishing and painting. This complex process also generates significant VOC and dust pollution. Summary of the Invention

[0004] In view of this, the present invention aims to propose an integrally molded synthetic sleeper, a manufacturing process and a manufacturing apparatus. One of the problems to be solved is that the existing synthetic sleepers use unidirectional continuous glass fiber reinforcement but have no transverse fiber reinforcement, which poses a risk of transverse cracking during use. The second problem to be solved is that during production, a release agent needs to be sprayed on the mold surface to facilitate the demolding of the sleeper. After demolding, the product surface needs to be polished and painted, which makes the production process complex and generates a lot of VOC and dust pollution.

[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0006] A one-piece molded synthetic railway sleeper includes a polyurethane resin matrix, with continuous glass fibers longitudinally arranged within the polyurethane resin matrix for longitudinal reinforcement. A reinforcing layer composed of glass fiber fabric and polyurethane resin is disposed on the surface of the polyurethane resin matrix, the thickness of which is 1–10 mm. The overall density of the synthetic sleeper is 0.64–1.4 g / cm³. 3Polyurethane resin accounts for 35-50% of the total weight of the synthetic sleeper; continuous glass fiber accounts for 35-60% of the total weight of the synthetic sleeper; and glass fiber fabric accounts for 3-10% of the total weight of the synthetic sleeper.

[0007] A reinforcing layer is applied to the surface of the synthetic sleeper, which significantly increases the overall strength of the sleeper and prevents lateral cracking. The reinforcing layer is made of polyurethane resin reinforced with fiberglass fabric. The fiberglass fabric is a composite felt of a specific color, which is used to produce synthetic sleepers of the required color. This reduces the painting process and minimizes environmental pollution. The color of the synthetic sleeper can be customized to meet the individual needs of different customers. This ensures that the color of the synthetic sleeper remains consistent throughout the entire production process, which helps to improve the appearance quality of the product and increase its aesthetics and consistency.

[0008] Furthermore, the polyurethane resin is composed of component A and component B in a weight ratio of 100:100-150; wherein component A is a polyol blend and component B is an isocyanate.

[0009] This setup ensures the performance and quality of the polyurethane resin, improving the overall strength and stability of the synthetic sleepers.

[0010] Furthermore, the average hydroxyl value of component A is 300-500 mg KOH / g, the viscosity at 25°C is 500-2000 mPa·s, and the functionality is 3-6; the isocyanate content of component B is 30-32%, the viscosity at 25°C is 200-600 mPa·s, and the functionality is 2-3.

[0011] The polyurethane resin obtained by mixing component A and component B has moderate reactivity and viscosity, which is conducive to the impregnation of continuous glass fibers and glass fiber fabrics. The polyurethane foaming and curing process is stable, and the resulting composite material sleeper has high strength.

[0012] Furthermore, the areal density of the glass fiber fabric is 300–1500 g / m². 2 .

[0013] This design allows for adjustment of the areal density of the fiberglass fabric according to actual application conditions, enabling the production of synthetic sleepers with varying surface reinforcement layer thicknesses to meet different usage requirements.

[0014] This application also provides a manufacturing process for an integrally molded synthetic railway sleeper, used to manufacture the aforementioned integrally molded synthetic railway sleeper, comprising the following steps:

[0015] Step S1: Calculate the number of continuous glass fibers based on the density and glass fiber content of the synthetic sleeper;

[0016] Step S2: Layer the continuous glass fiber according to the calculation results;

[0017] Step S3: Uniformly impregnate the layered continuous glass fibers with polyurethane resin.

[0018] Step S4: Gradually wrap the continuous glass fiber impregnated with polyurethane resin with glass fiber fabric and release paper;

[0019] Step S5: Heat the continuous glass fiber and polyurethane resin after covering the glass fiber fabric and release paper, and the polyurethane resin is cured to form a fiber-reinforced polyurethane synthetic sleeper.

[0020] Step S6: Cut the cured fiber-reinforced polyurethane synthetic sleeper into sections according to the size requirements to obtain the finished synthetic sleeper.

[0021] By calculating the number of continuous glass fibers, the appropriate fiber quantity can be determined based on the density and glass fiber content of the synthetic sleeper, thereby controlling the density and performance of the synthetic sleeper. Layered continuous glass fibers can better bond with polyurethane resin, improving the overall strength and stability of the synthetic sleeper. The overall surface coating with glass fiber fabric not only increases the surface strength of the synthetic sleeper and prevents transverse cracking, but also forms a reinforcing layer on the surface, creating a sandwich structure that improves the overall mechanical properties of the product. Furthermore, wrapping the glass fiber fabric with release paper facilitates product demolding, eliminating the need for release agents and surface polishing, thus reducing VOC and dust pollution during the production process.

[0022] This application also provides a preparation apparatus for an integrally molded synthetic railway sleeper, used to prepare the aforementioned integrally molded synthetic railway sleeper, comprising a yarn frame, a closed impregnation box, a glue injection machine, a felt guide, a felt frame, a track machine, and a sawing machine arranged in sequence. The felt guide includes a first felt guide and a second felt guide, and the felt frame includes a first felt frame and a second felt frame. The yarn frame is used to place continuous glass fibers, the closed impregnation box is used to uniformly impregnate the continuous glass fibers with polyurethane resin, the glue injection machine is used to deliver polyurethane resin into the closed impregnation box, the first felt frame is used to place glass fiber fabric, the first felt guide is used to guide the glass fiber fabric to cover the surface of the continuous glass fibers, the second felt frame is used to place release paper, the second felt guide is used to guide the release paper to cover the surface of the glass fiber fabric, the track machine is equipped with a mold, the mold is used to heat and pressurize the glass fibers impregnated with polyurethane resin, so that the polyurethane resin is cured to form a fiber-reinforced polyurethane synthetic railway sleeper, and the sawing machine is used to cut the fiber-reinforced polyurethane synthetic railway sleeper.

[0023] This setup reduces the number of steps in the production of synthetic sleepers, significantly improves production efficiency, and ensures the quality and consistency of synthetic sleepers.

[0024] Furthermore, the tracked machine includes a lower tracked machine and an upper tracked machine. Baffles are provided on the left and right sides of the tracked machine. The baffles cooperate with the upper tracked machine and the lower tracked machine to form a mold cavity. The synthetic sleeper is solidified and formed in the mold cavity and automatically separates from the mold cavity as the tracked machine rotates.

[0025] This setup not only allows for precise control of the shape and size of the synthetic sleepers, ensuring product consistency and quality, but also improves production efficiency and ease of operation.

[0026] Furthermore, the dispensing machine includes an A-component tank, a B-component tank, a mixing nozzle, and a distributor. The A-component tank and the B-component tank are connected to the mixing nozzle via pipelines. The mixing nozzle is connected to the distributor via a pipeline. The distributor is connected to the sealed impregnation box via a dispensing pipe. The A-component tank is used to store polyurethane resin A, the B-component tank is used to store polyurethane resin B, the mixing nozzle is used to mix polyurethane resin A and polyurethane resin B, and the distributor is used to evenly distribute the mixed polyurethane resin output from the mixing nozzle and input it into the sealed impregnation box.

[0027] This setup ensures that polyurethane resin A and polyurethane resin B are fully mixed to form a uniform mixed polyurethane resin, which is then evenly distributed on the surface of the continuous glass fiber, ensuring uniform impregnation of the glass fiber.

[0028] Furthermore, the traction speed of the mold is 0.3 to 1.0 m / min, the mold temperature is 40 to 90°C, and the curing time of the synthetic sleeper in the mold is 40 to 60 min.

[0029] This setup allows the synthetic sleepers to fully solidify within the mold, improving product quality and production efficiency. Beneficial effects

[0030] Compared with existing technologies, the one-piece molded synthetic railway sleeper, its manufacturing process, and its manufacturing apparatus described in this invention have the following advantages:

[0031] 1) It can significantly increase the overall strength of synthetic sleepers, including but not limited to the finished product's bending strength, the pull-out strength of the spikes, the lateral compressive strength, etc., and can prevent lateral cracking;

[0032] 2) The process of spraying release agent, surface sanding and painting has been reduced, which has reduced VOC and dust pollution in the production process and reduced environmental pollution.

[0033] 3) The entire surface is wrapped with fiberglass cloth reinforcement material. This has several advantages: ① It improves the lateral strength of the composite sleeper and prevents lateral cracking; ② The composite sleeper has a reinforcement layer on the top, bottom, left, and right surfaces, forming a sandwich-like structure that effectively improves the stress safety of the composite sleeper; ③ Release film is used as the release paper during the production process, so there is no release agent on the surface of the product. The entire surface is wrapped with fiberglass cloth, and the sleeper has a neat appearance. No post-processing grinding is required, which reduces pollution and waste of raw materials caused by release agents and grinding dust. If colored surface felt is used, the painting process can be reduced. Attached Figure Description

[0034] Figure 1 is a schematic diagram of the overall structure of the integral molding synthetic sleeper preparation device according to an embodiment of the present invention;

[0035] Figure 2 is a schematic diagram of the felt guide device in Figure 1;

[0036] Figure 3 is a schematic diagram of the structure of the synthetic sleeper according to an embodiment of the present invention;

[0037] Explanation of reference numerals in the attached figures:

[0038] 1. Yarn frame; 11. Continuous glass fiber; 2. Enclosed impregnation box; 3. Glue injection machine; 31. Component A tank; 32. First Component B tank; 33. First mixing nozzle; 34. Diverter; 35. Diverting glue injection tube; 36. Component C tank; 37. Second Component B tank; 38. Second mixing nozzle; 39. Second glue injection tube; 4. Felt guide; 41. First felt guide; 42. Second felt guide; 5. Felt frame; 51. First felt frame; 511. Glass fiber fabric; 52. Second felt frame; 521. Release paper; 6. Track machine; 61. Lower track machine; 62. Upper track machine; 7. Sawing machine; 100. Synthetic sleeper; 101. Polyurethane resin matrix; 102. Reinforcing layer. Detailed Implementation

[0039] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0040] As shown in Figures 1-3, a one-piece molded synthetic railway sleeper includes a polyurethane resin matrix 101, with continuous glass fibers 11 longitudinally arranged within the polyurethane resin matrix 101 for longitudinal reinforcement. A reinforcing layer 102 composed of a glass fiber fabric 511 and polyurethane resin is disposed on the surface of the polyurethane resin matrix 101, the thickness of which is 1–10 mm. The overall density of the synthetic railway sleeper is 0.64–1.4 g / cm³. 3Polyurethane resin accounts for 35-50% of the total weight of the synthetic sleeper 100; continuous glass fiber 11 accounts for 35-60% of the total weight of the synthetic sleeper 100; and glass fiber fabric 511 accounts for 3-10% of the total weight of the synthetic sleeper 100.

[0041] Specifically, the continuous glass fibers 11 are longitudinally arranged within the polyurethane resin matrix 101, which can increase the longitudinal strength and stability of the composite sleeper 100. The fiber fabric reinforcement layer 102 is provided on the surface of the composite sleeper 100, which can significantly increase the transverse strength of the composite sleeper 100 and prevent transverse cracking. The composite sleeper with the added reinforcement layer on the surface forms a sandwich structure, which has higher overall strength. The thickness of the reinforcement layer 102 ranges from 1 to 10 mm, and the appropriate thickness can be flexibly selected according to the specific application scenario, thus expanding the application range. The material ratio in this application can further improve the performance and quality of the composite sleeper 100.

[0042] Preferably, the continuous glass fiber 11 is configured as alkali-free glass fiber direct yarn or ply yarn, with a linear density of 4800-19200 tex.

[0043] Preferably, the fiberglass fabric 511 is a composite felt of a set color, used to produce synthetic sleepers 100 of the required color. This reduces the painting process, lessens environmental pollution, and allows the color of the synthetic sleepers 100 to be customized according to requirements, meeting the personalized needs of different customers. It also ensures that the color of the synthetic sleepers 100 remains consistent throughout the production process, which helps to improve the appearance quality of the product and increase its aesthetics and consistency.

[0044] Preferably, the glass fiber fabric 511 is one or more combinations of continuous felt, stitch-woven felt, chopped strand mat, knitted felt, mesh fabric, and biaxial fabric made of glass fiber, carbon fiber, basalt fiber, nylon fiber, or polyester fiber.

[0045] As a preferred example of the present invention, the polyurethane resin is composed of component A and component B in a weight ratio of 100:100-150; wherein component A is a polyol blend and component B is an isocyanate.

[0046] Specifically, polyols have good elasticity and flexibility, which can increase the durability and impact resistance of the synthetic sleeper 100, and can also provide suitable viscosity and flowability; isocyanates can control the hardness, strength and durability of polyurethane resin, so that the synthetic sleeper 100 has appropriate rigidity and strength. This setting can ensure the performance and quality of polyurethane resin, and ensure the uniform impregnation of polyurethane mixed resin with glass fiber reinforcement, thereby improving the overall strength and stability of the synthetic sleeper 100.

[0047] As a preferred example of the present invention, the average hydroxyl value of component A is 300-500 mg KOH / g, the viscosity at 25°C is 500-2000 mPa·s, and the functionality is 3-6; the isocyanate content of component B is 30-32%, the viscosity at 25°C is 200-600 mPa·s, and the functionality is 2-3.

[0048] Specifically, the average hydroxyl value ranges from 300 to 500 mgKOH / g, providing sufficient reactivity to facilitate the reaction with the isocyanate of component B to form polyurethane resin. The moderate viscosity is beneficial for the mixing of polyurethane components A and B, as well as the uniform impregnation of glass fiber reinforcement. Higher functionality leads to a higher degree of cross-linking of the polyurethane resin, increasing hardness and strength, which helps improve the hardness and strength of the synthetic sleeper. This configuration provides sufficient reactivity and viscosity to facilitate the reaction of component A and component B to form polyurethane resin, and can improve the hardness and strength of the synthetic sleeper.

[0049] As a preferred example of the present invention, the areal density of the glass fiber fabric 511 is 300-1500 g / m². 2 It can be one layer or multiple layers.

[0050] Specifically, the higher the areal density of the fiberglass fabric and the more layers it has, the thicker the reinforcing layer, and the higher the lateral strength of the composite sleeper. The areal density of the 511 fiberglass fabric can be adjusted according to the actual application conditions to produce composite sleepers with different surface reinforcing layer thicknesses.

[0051] Furthermore, the surface fiber fabric reinforcement layer is formed using glass fiber cloth and reinforced polyurethane resin. The reinforced polyurethane resin is composed of a C component and a B component mixed in a weight ratio of 100:100-180, wherein the B component is a polyisocyanate, and the C component is a mixture of the aforementioned A component (polyurethane composite) and polyether urethane resin. After the B and C components are mixed and reacted, a polyurea-urethane block polymer is formed. This block polymer has good strength and toughness, significantly improving the strength and wear resistance of the surface reinforcement layer.

[0052] Furthermore, the water content of component C is ≤0.2%, and after reacting with component B, the foam density is high, resulting in a high-density reinforcing layer, reaching 1.0~1.6 g / cm³. 3 Therefore, it has high surface strength.

[0053] Furthermore, the polyether amine resin is an aliphatic amino-terminated polyether with a molecular weight of 400-2000 and a functionality of 2-3, accounting for 10%-30% of component C. The polyether amine resin exhibits high reactivity with isocyanate; the reaction is exothermic, which accelerates the reaction rate between the polyol resin and component B, and speeds up the curing of the surface reinforcement layer. This reduces the use of catalysts, lowers mold temperature, and reduces production energy consumption.

[0054] In actual use, the stress on sleepers varies under different operating conditions, and the ease with which sleepers may fail also differs significantly between different sections of the same line, leading to varying strength requirements for the sleepers. For example, on the same line, sleepers are more prone to lateral cracking in bridge areas and areas with small radii. Since the core materials of sleepers from the same batch are essentially the same, it is necessary to adjust the thickness of the fiber fabric reinforcement layer on the sleeper surface to adjust the lateral and overall strength of the sleeper. The thickness of the fiber fabric reinforcement layer on the sleeper surface is determined through the following methods:

[0055] (1) Calculate the bending moment of the sleeper

[0056]

[0057] M—positive bending moment borne by the sleeper, kN·m;

[0058] P d —The sleeper bears a dynamic load of kN;

[0059] e—length of the rail support, in meters;

[0060] a1——The distance from the center of the sleeper bearing groove to the sleeper end, in meters;

[0061] b1——Sleeper pressure distribution width, m.

[0062] (2) Test the stress σ on the top surface of the sleeper under different track or different train axle load conditions.

[0063] σ=

[0064] Where σ is the transverse bearing dynamic stress of the sleeper.

[0065] F is the contact area between the rail base or pad and the sleeper;

[0066] R d For the dynamic pressure of the rail.

[0067] (3) The surface strength of the sleeper must be at least three times the stress borne by the top surface of the sleeper to ensure that the sleeper does not break. However, excessive surface strength of the sleeper will cause unnecessary waste and excessive track stiffness, which will have an adverse effect on the track foundation and the comfort of train operation. Therefore, the surface strength of the sleeper has a certain range. The minimum value ensures that it does not break, and the maximum value ensures that the surface strength is not too high. The minimum value is three times the stress borne by the top surface of the sleeper, i.e., 3σ, and the maximum value is 3σ(1+β), where β is the eccentric load factor, which is generally taken as 0.15~0.2.

[0068] The distance from different stress points to the neutral axis is calculated based on the stress and bending moment of the sleeper.

[0069] σ g =

[0070] Where, σ g M is the maximum or minimum value in step (2) above, M is the sleeper bending moment in step (1) above, I is the moment of inertia of the sleeper section, and y is the distance from different stress points to the neutral axis.

[0071] The corresponding y-values ​​are calculated based on the maximum and minimum surface strength values, which represent the distances from the inner and outer sides of the reinforcing layer to the neutral axis. The difference between these two values ​​is the thickness of the reinforcing layer. This allows for adaptive setting of the thickness of the fiber fabric reinforcing layer on the sleeper surface, ensuring sleeper strength under different conditions without increasing the pressure and vibration acceleration on the track bed, thus guaranteeing train operation safety and extending the sleeper's service life.

[0072] This application also provides a manufacturing process for an integrally molded synthetic railway sleeper, used to manufacture the aforementioned integrally molded synthetic railway sleeper, comprising the following steps:

[0073] Step S1: Calculate the number of continuous glass fibers 11 based on the density and glass fiber content of the synthetic sleeper 100;

[0074] Step S2: Layer the continuous glass fiber 11 according to the calculation results;

[0075] Step S3: Uniformly impregnate the layered continuous glass fiber 11 with polyurethane resin.

[0076] Step S4: Cover the continuous glass fiber 11 impregnated with polyurethane resin with a surface glass fiber fabric reinforcement layer 511; wherein the surface glass fiber fabric reinforcement layer is made of glass fiber impregnated with a reinforced polyurethane resin composed of a mixture of component C and component B; after covering the surface glass fiber fabric reinforcement layer 511, cover it with release paper 521.

[0077] Step S5: Heat the continuous glass fiber 11 and polyurethane resin after covering the glass fiber fabric 511 and release paper 521, and the polyurethane resin is cured to form fiber-reinforced polyurethane synthetic sleeper 100.

[0078] Step S6: Cut the cured fiber-reinforced polyurethane synthetic sleeper 100 into sections according to the size requirements to obtain the finished synthetic sleeper 100.

[0079] Specifically, the appropriate number of fibers can be determined based on the density and glass fiber content of the synthetic sleeper 100, and the layering can be controlled. The layered continuous glass fiber 11 can better bond with the polyurethane resin, improving the overall strength and stability of the synthetic sleeper 100. The glass fiber fabric 511 can increase the surface transverse strength of the synthetic sleeper and prevent transverse cracking. The release paper 521 wrapped around the glass fiber fabric 511 facilitates the demolding of the product, eliminating the need for spraying release agent and surface polishing, thus reducing VOC and dust pollution during the production process.

[0080] This application also provides a manufacturing apparatus for an integrally molded synthetic railway sleeper, used to manufacture the aforementioned integrally molded synthetic railway sleeper, comprising a yarn frame 1, a closed impregnation box 2, a glue injection machine 3, a felt guide 4, a felt frame 5, a track machine 6, and a sawing machine 7 arranged sequentially. The felt guide 4 includes a first felt guide 41 and a second felt guide 42, and the felt frame 5 includes a first felt frame 51 and a second felt frame 52. The yarn frame 1 is used to place continuous glass fibers 11, the closed impregnation box 2 is used to coat the surface of the continuous glass fibers 11 with polyurethane resin, and the glue injection machine 3 is used to deliver polyurethane resin into the closed impregnation box 2. The felt frame 51 is used to place the fiberglass fabric 511, the first felt guide 41 is used to guide the fiberglass fabric 511 to cover the surface of the continuous fiberglass 11, the second felt frame 52 is used to place the release paper 521, the second felt guide 42 is used to guide the release paper 521 to cover the surface of the fiberglass fabric 511, the track machine 6 is equipped with a mold, the mold is used to heat and press the continuous fiberglass 11 coated with polyurethane resin, so that the polyurethane resin is cured to form fiber-reinforced polyurethane synthetic sleeper 100, and the sawing machine 7 is used to cut the fiber-reinforced polyurethane synthetic sleeper 100.

[0081] Specifically, the yarn frame 1 is equipped with a yarn separating plate for separating the continuous glass fiber 11 into layers. The continuous glass fiber 11 is drawn out from the yarn frame 1 and passes through the yarn separating plate, the closed impregnation box 2, the first guide felt 41, and the second guide felt 42 in sequence from front to back before entering the track machine 6. The continuous glass fiber 11 moves backward under the compression and traction of the track machine 6. This arrangement can reduce the number of production steps in the composite sleeper, greatly improve production efficiency, and ensure the quality and consistency of the composite sleeper 100.

[0082] Preferably, a release liner can also be used, wherein the release liner / sheet comprises at least one of polyethylene release film, polypropylene release film, polytetrafluoroethylene release film, polyester release film, coated release paper, and nonwoven fabric.

[0083] As a preferred example of the present invention, the track machine 6 includes a lower track machine 61 and an upper track machine 62. Baffles are provided on the left and right sides of the track machine 6. The baffles cooperate with the upper track machine 62 and the lower track machine 61 to form a mold cavity. The composite sleeper 100 is solidified and formed in the mold cavity and automatically separates from the mold cavity as the track machine 6 rotates.

[0084] Specifically, this setup can accurately control the shape and size of the synthetic sleeper 100, ensuring product consistency and quality, while also improving production efficiency and ease of operation.

[0085] As a preferred example of the present invention, the dispensing machine 3 includes an A-component tank 31, a B-component tank 32, a mixing nozzle 33, and a distributor 34. The A-component tank 31 and the B-component tank 32 are respectively connected to the mixing nozzle 33 through pipelines. The mixing nozzle 33 is connected to the distributor 34 through pipelines. The distributor 34 is connected to the closed impregnation box 2 through a dispensing pipe 35. The A-component tank 31 is used to store polyurethane resin A, the B-component tank 32 is used to store polyurethane resin B, the mixing nozzle 33 is used to mix polyurethane resin A and polyurethane resin B, and the distributor 34 is used to evenly distribute the mixed polyurethane resin output from the mixing nozzle 33 and input it into the closed impregnation box 2.

[0086] The glue dispensing machine 3 also includes a C-component tank 36, a second B-component tank 37, a second mixing nozzle 38, and a second dispensing tube 39 disposed downstream of the closed impregnation box 2. The C-component tank 36 and the second B-component tank 37 are connected to the second mixing nozzle 38 through a pipeline. The second mixing nozzle 38 introduces the reinforced polyurethane resin onto the surface glass fiber cloth through the second dispensing tube 39.

[0087] Specifically, the mixing of polyurethane resin A and polyurethane resin B by the mixing gun 33 ensures thorough mixing, forming a uniform mixed polyurethane resin with better flowability and wettability, thus improving the consistency and quality of the composite sleeper 100. The mixed polyurethane resin output from the mixing gun 33 is evenly distributed into the closed impregnation box 2 by the distributor 34, ensuring that the mixed polyurethane resin is evenly distributed on the surface of the continuous glass fiber 11 during the injection process, thereby improving the quality and strength of the composite sleeper 100. This configuration ensures that polyurethane resin A and polyurethane resin B are thoroughly mixed, forming a uniform mixed polyurethane resin, and evenly distributed on the surface of the continuous glass fiber 11, thus improving the quality and strength of the composite sleeper 100.

[0088] Preferably, the mixing nozzle 33 is connected to the distributor 34 and is connected to multiple injection holes of the closed impregnation box 2 through multiple injection tubes 35 to ensure uniform injection of polyurethane resin and uniform impregnation of continuous glass fiber 11.

[0089] As a preferred example of the present invention, the traction speed of the mold is 0.3 to 1.0 m / min, the mold temperature is 40 to 90°C, and the curing time of the composite sleeper 100 in the mold is 40 to 60 min.

[0090] Specifically, by controlling the traction speed, mold temperature, and curing time, the synthetic sleeper 100 can be fully cured in the mold, improving product quality and production efficiency.

[0091] Example 1

[0092] The hydroxyl value of component A of the polyurethane compound is 320±20mgKOH / g, and the viscosity is 1200mPas. Component B is selected as polymeric MDI with an isocyanate index of 31.2%. The mass ratio of component A to component B is set to 100:100. Components A and B are pumped into the dispensing machine in advance for later use.

[0093] By changing the position of the baffle and the distance between the lower tracker 61 and the upper tracker 62, the mold cavity size of the tracker 6 is adjusted to 200mm (width) × 140mm (height), based on a product density of 0.70±0.04g / cm³. 3 With a glass fiber content of 50%, the reinforcing material uses 1030 bundles of 9600tex continuous glass fiber 11 direct yarn. The continuous glass fiber 11 is passed through the closed impregnation box 2 into the mold, and then enters the mold cavity of the track machine 6 under the extrusion and traction. The glass fiber fabric 511 has a width of 700mm and an areal density of 600g / m². 2 The continuous felt consists of two layers. The felt guide 4 uses a layer of PET release paper 521 as the release paper, with a width of 720mm and a surface density of 90g / m³. 2 The glass fiber fabric 511 and the release paper 521 are wrapped together with the continuous glass fiber and then enter the mold.

[0094] When the mold temperature of the track machine 6 is preheated to 50℃, the glue injection machine 3 is turned on to inject glue. After the continuous glass fiber 11 is impregnated with polyurethane resin, glass fiber fabric 511 and release paper 521 are wrapped around it in sequence. The resin flow rate of the glue injection machine 3 is adjusted in time to ensure that the polyurethane resin is evenly impregnated on the continuous glass fiber 11 and the fiber fabric 511. The production speed is controlled at 0.75m / min. After the product is cured in the mold for 40 minutes, demolding begins. After demolding, the product is sawn according to the set length. After sawing, the release paper 521 is cleaned to obtain the finished synthetic sleeper 100. The thickness of the glass fiber fabric reinforcement layer 102 on the surface of the finished synthetic sleeper 100 is 1.5mm.

[0095] Example 2

[0096] The hydroxyl value of component A of the polyurethane compound is 400±20mgKOH / g, and the viscosity is 800mPas. Component B is selected as polymeric MDI with an isocyanate index of 31.2%. The mass ratio of component A to component B is set to 100:120. Components A and B are pumped into the dispensing machine in advance for later use.

[0097] By changing the position of the baffle and the distance between the lower tracker 61 and the upper tracker 62, the mold cavity size of the tracker 6 is adjusted to 230mm (width) × 140mm (height), based on a product density of 0.80±0.04g / cm³. 3 With a glass fiber content of 50%, the reinforcing material uses 840 bundles of 13800tex continuous glass fiber ply yarn. The continuous glass fiber 11 is passed through the closed impregnation box 2 into the mold, and then enters the mold cavity of the track machine 6 under the extrusion and traction. The glass fiber fabric 511 has a width of 750mm and uses 3 layers with a density of 600g / m². 2 The density of the fiberglass mesh + 1 layer is 450g / m². 2 The polyester stitch-woven composite felt is black. The felt guide 4 uses a layer of PE release film as the release paper 521, with a width of 770mm and a surface density of 120g / m³. 2 The glass fiber fabric 511 and the release paper 521 are wrapped together with the continuous glass fiber and then enter the mold.

[0098] When the mold temperature of the track machine 6 is preheated to 60℃, the glue injection machine 3 is turned on to inject glue. After the continuous glass fiber 11 is impregnated with polyurethane resin, glass fiber fabric 511 and release paper 521 are wrapped around it in sequence. The resin flow rate of the glue injection machine 3 is adjusted in time to ensure that the polyurethane resin is evenly impregnated on the continuous glass fiber 11 and the fiber fabric 511. The production speed is controlled at 0.6m / min. After the product is cured in the mold for 50 minutes, demolding begins. After demolding, the product is sawn according to the set length. After sawing, the release paper 521 is cleaned to obtain the black synthetic sleeper 100 finished product. The thickness of the glass fiber fabric reinforcement layer 102 on the surface of the synthetic sleeper 100 finished product is 3mm.

[0099] Example 3

[0100] The hydroxyl value of component A of the polyurethane compound is 480±20mgKOH / g, and the viscosity is 700mPas. Component B is selected as polymeric MDI with an isocyanate index of 31.2%. The mass ratio of component A to component B is set to 100:140. Components A and B are pumped into the dispensing machine in advance for later use.

[0101] By changing the position of the baffle and the distance between the lower tracker 61 and the upper tracker 62, the mold cavity size of the tracker 6 is adjusted to 240mm (width) × 240mm (height), based on a product density of 1.20±0.06g / cm³. 3 With a glass fiber content of 55%, the reinforcing material uses 19200 tex continuous glass fiber ply yarn, totaling 1990 bundles. The continuous glass fiber 11 is passed through the closed impregnation box 2 into the mold, and then extruded and pulled into the mold cavity of the track machine 6. The glass fiber fabric 511 has a width of 980 mm and a ply density of 600 g / m². 2 0° / 90° glass fiber biaxial fabric + 1 layer, density 450g / m 2 The continuous felt, the felt guide 4 uses a layer of PET release paper 521 as the release paper, with a width of 1000mm and a surface density of 120g / m³. 2 The glass fiber fabric 511 and the release paper 521 are wrapped together with the continuous glass fiber and then enter the mold.

[0102] When the mold temperature of the track machine 6 is preheated to 60℃, the glue injection machine 3 is turned on to inject glue. After the continuous glass fiber 11 is impregnated with polyurethane resin, glass fiber fabric 511 and release paper 521 are wrapped around it in sequence. The resin flow rate of the glue injection machine 3 is adjusted in time to ensure that the polyurethane resin is evenly impregnated on the continuous glass fiber 11 and fiber fabric 511. The production speed is controlled at 0.55m / min. After the product is cured in the mold for 50 minutes, demolding begins. After demolding, the product is sawn according to the set length. After sawing, the release paper 521 is cleaned to obtain the finished synthetic sleeper 100. The thickness of the glass fiber fabric reinforcement layer 102 on the surface of the finished synthetic sleeper 100 is 6mm.

[0103] Example 4

[0104] When the continuous glass fiber 11 impregnated with polyurethane resin is covered with a surface glass fiber fabric reinforcement layer 511, the surface glass fiber fabric reinforcement layer is made of glass fiber impregnated with a polyurethane resin composed of a mixture of component C and component B. After covering the surface glass fiber fabric reinforcement layer 511, release paper 521 is then covered. The mass ratio of component B to component C is 140:100, the water content of component C is 0.18%, the polyether amino resin content is 20wt%, and the molecular weight is 1000~1200. Other parameters and conditions in this embodiment are the same as in Example 3.

[0105] Comparative Example 1

[0106] The reinforcing material is made entirely of 9600tex continuous glass fiber direct yarn, with 1120 bundles arranged, and there is no glass fiber fabric reinforcement on the surface.

[0107] All other molding process parameters are the same as in "Example 1".

[0108] Comparative Example 2

[0109] The reinforcing material is made entirely of 13800tex continuous glass fiber yarn, with 900 bundles arranged in a row, and there is no glass fiber fabric reinforcement on the surface.

[0110] All other molding process parameters are the same as in "Example 2".

[0111] Comparative Example 3

[0112] The reinforcing material is made entirely of 9600tex continuous glass fiber direct yarn, with 2180 bundles arranged in a single layer, and no glass fiber fabric reinforcement on the surface.

[0113] All other molding process parameters are the same as in "Example 3".

[0114] Performance testing

[0115] In the above examples and comparative examples, the density was determined according to GB / T1463-2005 "Test Method for Density and Relative Density of Fiber Reinforced Plastics"; the mechanical properties of Examples 1 and 2 and Comparative Examples 1 and 2 were tested according to CJ / T399-2012 "Polyurethane Foam Synthetic Railway Sleepers" standard; the mechanical properties of Examples 3 and Comparative Example 3 were tested according to the provisional technical conditions of TJ / GW161-2018 "HFFP Composite Bridge Sleepers for Railway Steel Beams".

[0116] The fiber-reinforced polyurethane composite railway sleepers obtained in Examples 1-3 and Comparative Examples 1-3 were tested, and the specific results are shown in Table 1.

[0117] Table 1. Performance Comparison of Synthetic Railway Sleeper Products from Examples and Comparative Examples

[0118]

[0119] Note 1. Compressive strength measurements were taken from the product surface;

[0120] 2. The direction along the fiber is vertical; the direction perpendicular to the fiber is horizontal.

[0121] As shown in Table 1, for the embodiment and comparative products with similar densities, except for the vertical compressive strength, the lateral compressive strength, threaded spike pull-out strength, and finished product bending load of the embodiment product are all greater than those of the comparative product. This proves that the surface reinforcement layer of the present invention can significantly increase the overall strength of the synthetic sleeper and has obvious advantages in performance compared with the existing unidirectional fiber reinforced synthetic sleepers.

[0122] In summary, the integrally molded synthetic sleeper, manufacturing process, and manufacturing apparatus described in this application have the following advantages: 1. They can significantly increase the overall strength of the synthetic sleeper 100, avoid lateral cracking, and improve the service life of the synthetic sleeper; 2. They reduce the painting process, reduce environmental pollution, and allow for customization of the color of the synthetic sleeper 100 to meet the personalized needs of different customers. They can ensure that the color of the synthetic sleeper 100 remains consistent throughout the entire production process, which helps improve the appearance quality of the product. They also have good durability and anti-aging properties, ensuring that the color of the synthetic sleeper 100 remains bright and stable even after long-term use; 3. They facilitate product demolding, eliminating the need for spraying release agents and surface polishing, thus reducing VOC and dust pollution during the production process.

[0123] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A one-piece molded synthetic railway sleeper, characterized in that, The composite sleeper (100) comprises a polyurethane resin matrix (101), with continuous glass fibers (11) longitudinally arranged within the polyurethane resin matrix (101) for longitudinal reinforcement. A reinforcing layer (102) composed of glass fiber fabric (511) and polyurethane resin is disposed on the surface of the polyurethane resin matrix (101), the thickness of which is 1–10 mm. The overall density of the composite sleeper is 0.64–1.4 g / cm³. 3 Polyurethane resin accounts for 35-50% of the total weight of the synthetic sleeper (100); continuous glass fiber (11) accounts for 35-60% of the total weight of the synthetic sleeper (100); and glass fiber fabric (511) accounts for 3-10% of the total weight of the synthetic sleeper (100).

2. The integrally molded synthetic railway sleeper according to claim 1, characterized in that, The polyurethane resin is composed of component A and component B in a weight ratio of 100:100-150; wherein component A is a polyol blend and component B is an isocyanate.

3. The integrally formed synthetic tie tie of claim 2, wherein, The average hydroxyl value of component A is 300-500 mg KOH / g, the viscosity at 25°C is 500-2000 mPa·s, and the functionality is 3-6; the isocyanate content of component B is 30-32%, the viscosity at 25°C is 200-600 mPa·s, and the functionality is 2-3.

4. The integrally molded synthetic railway sleeper according to claim 1, characterized in that, The areal density of the glass fiber fabric (511) is 300-1500 g / m³. 2 .

5. A manufacturing process for an integrally molded synthetic railway sleeper, used to manufacture the integrally molded synthetic railway sleeper according to any one of claims 1-4, characterized in that, Including the following steps: Step S1: Calculate the number of continuous glass fibers (11) based on the density and glass fiber content of the synthetic sleeper (100); Step S2: Layer the continuous glass fiber (11) according to the calculation results; Step S3: Uniformly impregnate the layered continuous glass fiber (11) with polyurethane resin. Step S4: Gradually wrap the glass fiber fabric (511) and release paper (521) on the outside of the continuous glass fiber (11) after impregnation with polyurethane resin. Step S5: Heat the continuous glass fiber (11) and polyurethane resin after covering the glass fiber fabric (511) and release paper (521), and the polyurethane resin is cured to form a fiber-reinforced polyurethane synthetic sleeper (100). Step S6: Cut the cured fiber-reinforced polyurethane synthetic sleeper (100) into sections according to the size requirements to obtain the finished synthetic sleeper (100).

6. An apparatus for producing a monolithic synthetic sleeper according to any one of claims 1 to 4, characterized in that The system includes a yarn frame (1), a closed impregnation box (2), a glue injection machine (3), a felt guide (4), a felt frame (5), a track machine (6), and a sawing machine (7) arranged in sequence. The felt guide (4) includes a first felt guide (41) and a second felt guide (42). The felt frame (5) includes a first felt frame (51) and a second felt frame (52). The yarn frame (1) is used to place continuous glass fibers (11). The closed impregnation box (2) is used to uniformly impregnate the continuous glass fibers (11) with polyurethane resin. The glue injection machine (3) is used to deliver polyurethane resin into the closed impregnation box (2). The first felt frame (51) is used to place glass fiber fabric ( 511), the first felt guide (41) is used to guide the glass fiber fabric (511) to cover the surface of the continuous glass fiber (11), the second felt frame (52) is used to place the release paper (521), the second felt guide (42) is used to guide the release paper (521) to cover the surface of the glass fiber fabric (511), the track machine (6) is equipped with a mold, the mold is used to heat and press the continuous glass fiber (11) impregnated with polyurethane resin, so that the polyurethane resin is cured to form a fiber-reinforced polyurethane synthetic sleeper (100), and the sawing machine (7) is used to cut the fiber-reinforced polyurethane synthetic sleeper (100).

7. The apparatus for preparing an integrally molded synthetic railway sleeper according to claim 6, characterized in that, The track machine (6) includes a lower track machine (61) and an upper track machine (62). Baffles are provided on the left and right sides of the track machine (6). The baffles cooperate with the upper track machine (62) and the lower track machine (61) to form a mold cavity. The synthetic sleeper (100) is solidified in the mold cavity and automatically separates from the mold cavity as the track machine (6) rotates.

8. The apparatus for preparing an integrally molded synthetic railway sleeper according to claim 6, characterized in that, The dispensing machine (3) includes an A-component tank (31), a B-component tank (32), a mixing nozzle (33), and a distributor (34). The A-component tank (31) and the B-component tank (32) are connected to the mixing nozzle (33) through pipelines. The mixing nozzle (33) is connected to the distributor (34) through pipelines. The distributor (34) is connected to the closed impregnation box (2) through a dispensing pipe (35). The A-component tank (31) is used to store polyurethane resin A, the B-component tank (32) is used to store polyurethane resin B, the mixing nozzle (33) is used to mix polyurethane resin A and polyurethane resin B, and the distributor (34) is used to evenly distribute the mixed polyurethane resin output from the mixing nozzle (33) and input it into the closed impregnation box (2).

9. The apparatus for manufacturing a monolithic synthetic sleeper according to claim 6, wherein The traction speed of the mold is 0.3 to 1.0 m / min, the mold temperature is 40 to 90℃, and the curing time of the synthetic sleeper (100) in the mold is 40 to 60 min.

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