Fish plate, preparation method thereof and steel rail insulation joint

Abstract

The invention provides a fishplate, a preparation method thereof and a steel rail insulation joint, and is characterized in that the fishplate is prepared by compression molding of a laminated body containing epoxy resin prepreg; wherein the epoxy resin prepreg is prepared from 60 to 70 weight percent of reinforcing material and 30 to 40 weight percent of base material; the reinforcing material is multi-axial fiber cloth, and the multi-axial fiber cloth comprises 70 to 85 weight percent of glass fiber and 15 to 30 weight percent of aramid fiber according to the total weight of the multi-axial fiber cloth; the fishplate disclosed by the invention has good mechanical properties, a static bending test can reach 910KN or more, the overall shear strength can reach 510KN or more, the fatigue strength can reach 2 * 106 times, and the fishplate also has good insulating property and is particularly suitable for connection of heavy haul railway steel rails.

Description

Technical Field

[0001] The present invention relates to the technical field of heavy-haul railway rail connections, and particularly to a fishplate and a preparation method thereof, and a rail insulating joint. Background Art

[0002] A freight heavy-haul railway dedicated line is a railway that specifically runs large-axle-load freight cars or trains with extremely large freight volumes. The heavy-haul railway rails are connected together by fishplates and bolts. When the train wheels pass through the rail joints, the fishplates will be affected by various external forces periodically. For the heavy-haul railway steel fishplates, the metal fishplates are prone to fatigue damage under the action of large-load dynamic impact forces. When it exceeds its fatigue limit, it may cause the metal fishplate to suddenly break transversely, resulting in derailment accidents of the train, seriously affecting the driving safety of heavy-haul trains.

[0003] In order to solve the problems such as poor insulation reliability of existing heavy-haul railway steel fishplates, fiber-reinforced composite material heavy-haul railway rail fishplates with high strength, good fatigue resistance, and excellent insulation performance are developed. Summary of the Invention

[0004] Aiming at the problems of poor insulation reliability and mechanical properties of heavy-haul railway steel fishplates in the prior art, the present invention provides a fishplate and a preparation method thereof, and a rail insulating joint. The fishplate of the present invention has the advantages of high strength, good fatigue resistance, and excellent insulation performance, and is particularly suitable for the connection of heavy-haul railway rails.

[0005] The inventors of the present invention have found through research that a laminate containing an epoxy resin prepreg is prepared by using a multi-axial fiber cloth containing specific contents of glass fiber and aramid fiber as a reinforcing material and a matrix material for model molding to obtain a fishplate, which has good mechanical strength and fatigue resistance, and also has good insulation performance.

[0006] Based on the above research, in the first aspect, the present invention provides a fishplate, which is obtained by compression molding a laminate containing an epoxy resin prepreg;

[0007] Wherein, the epoxy resin prepreg includes 60-70 wt% of a reinforcing material and 30-40 wt% of a matrix material;

[0008] The reinforcing material is a multi-axial fiber cloth. Based on the total amount of the multi-axial fiber cloth, the multi-axial fiber cloth includes 70-85 wt% of glass fiber and 15-30 wt% of aramid fiber.

[0009] In the present invention, the multi-axial fiber cloth refers to a fiber fabric in which fibers in multiple axial directions are introduced in the fabric plane direction, forming a non-crimping fiber fabric with multiple axial directions. The arrangement angles of the fibers in each axial direction are 0°, +30°, +45°, +60°, +90°, -30°, -45° or -60°. The composition of the fibers in each axial direction can be the same or different.

[0010] In a preferred embodiment of the present invention, the epoxy resin prepreg comprises 62-68 wt% of a reinforcing material and 32-38 wt% of a matrix material.

[0011] In a preferred embodiment of the present invention, the multi-axial fiber cloth is prepared by mixing and weaving raw materials including glass fibers and aramid fibers.

[0012] In a preferred embodiment of the present invention, the surface gram weight of the multi-axial fiber cloth is 1000-2200 g / m 2 , preferably 1200-1800 g / m 2 .

[0013] In a preferred embodiment of the present invention, the tensile modulus of the glass fiber > 90 Gpa, preferably 95-97 Gpa. Using glass fibers with this preferred tensile modulus can improve the bending resistance of the fishplate.

[0014] In a preferred embodiment of the present invention, the breaking strength of the aramid fiber > 30 cN / dtex and the initial modulus > 70 N / tex. Using aramid fibers with this preferred performance can effectively improve the fatigue resistance of the fishplate.

[0015] In a preferred embodiment of the present invention, the aramid fiber is para-aramid fiber.

[0016] In a preferred embodiment of the present invention, the matrix material comprises epoxy resin.

[0017] A preferred embodiment of the present invention, the epoxy resin comprises 100 parts by weight of bisphenol A epoxy resin, 20-50 parts by weight of alicyclic epoxy resin, 20-40 parts by weight of epoxy toughening resin and 3-15 parts by weight of epoxy curing agent; preferably, the epoxy resin comprises 100 parts by weight of bisphenol A epoxy resin, 25-45 parts by weight of alicyclic epoxy resin, 25-35 parts by weight of epoxy toughening resin and 4-12 parts by weight of epoxy curing agent. Using the epoxy resin with the preferred component content can effectively improve the mechanical strength and insulation performance of the fishplate. The inventor further studies and finds that, relative to 100 parts by weight of bisphenol A epoxy resin, if the dosage of the epoxy curing agent is less than 5 parts by weight, the curing crosslinking density of the epoxy resin will be relatively low, thus affecting the properties such as the mechanical strength of the cured material; if the usage amount exceeds 15 parts by weight, it is not conducive to the molding operation. Using the preferred dosage of the epoxy curing agent of the present invention can effectively improve the mechanical strength of the matrix material, and further make the prepared fishplate have better mechanical properties.

[0018] A preferred embodiment of the present invention, the viscosity of the bisphenol A epoxy resin is 8000-15000 mPa·s (for example, it can be any value among 8000 mPa·s, 9000 mPa·s, 10000 mPa·s, 11000 mPa·s, 12000 mPa·s, 13000 mPa·s, 14000 mPa·s and 15000 mPa·s or any value between any two values). Using this preferred viscosity can effectively improve the interfacial bonding between the resin matrix and the reinforcing fibers and improve the comprehensive mechanical properties of the fishplate.

[0019] A preferred embodiment of the present invention, the alicyclic epoxy resin is selected from at least one of diglycidyl 4,5-epoxycyclohexane-1,2-dicarboxylate, tetraglycidylamine 4,4-diaminodiphenylmethane and triglycidyl p-aminophenol, preferably diglycidyl 4,5-epoxycyclohexane-1,2-dicarboxylate and / or triglycidyl p-aminophenol. Using this preferred alicyclic epoxy resin can enable the resin system to better infiltrate the reinforcing material, improve the interfacial bonding between the resin matrix and the reinforcing material, improve the comprehensive properties of the fishplate, and can also effectively improve the heat resistance of the fishplate and have a higher heat distortion temperature under load.

[0020] A preferred embodiment of the present invention, the epoxy toughening resin is selected from at least one of carboxyl-terminated liquid nitrile rubber, hyperbranched resin and reactive toughening resin, preferably carboxyl-terminated liquid nitrile rubber. Using this preferred epoxy toughening resin can further improve the toughness of the fishplate and has more excellent bending resistance.

[0021] A preferred embodiment of the present invention, the epoxy curing agent is an aromatic urea-based epoxy curing agent.

[0022] In a preferred embodiment of the present invention, the particle size of the epoxy curing agent is 2 - 20 μm, preferably 5 - 15 μm. With this preferred particle size, it has better miscibility with epoxy resin, which is beneficial to improving the comprehensive mechanical properties of the fishplate material.

[0023] In a preferred embodiment of the present invention, the thickness of the laminate is 40 - 60 mm, preferably 45 - 55 mm.

[0024] In a preferred embodiment of the present invention, the total content of glass fiber and aramid fiber extending along the length direction of the fishplate in the fishplate is 70 - 95 wt%, preferably 75 - 90 wt%. With this preferred content, it is beneficial to improving the mechanical strength of the fishplate.

[0025] In the second aspect, the present invention provides a method for preparing the fishplate described in the first aspect, and the preparation method includes the following steps:

[0026] Step (1): Mix and impregnate the reinforcing material and the matrix material to obtain an epoxy resin prepreg laminate;

[0027] Step (2): Cut the obtained laminate including the epoxy resin prepreg and lay it up according to the shape and thickness of the fishplate to obtain a preform;

[0028] Step (3): Mold the obtained preform by compression molding to obtain the fishplate.

[0029] In a preferred embodiment of the present invention, in step (1), before mixing the reinforcing material and the matrix material, under stirring conditions, add the epoxy curing agent to the mixture of bisphenol A epoxy resin, alicyclic epoxy resin and epoxy toughening resin, stir evenly and grind to obtain the matrix material.

[0030] In a preferred embodiment of the present invention, in step (2), the method further includes putting the obtained preform into a preheated mold, closing the mold, and keeping warm.

[0031] In a preferred embodiment of the present invention, in step (2), the temperature for keeping warm is 80 - 90 °C, and the time for keeping warm is 20 - 40 min.

[0032] In a preferred embodiment of the present invention, in step (3), the method of integral compression molding includes performing first compression molding, second compression molding and third compression molding on the preform in sequence.

[0033] A preferred embodiment of the present invention, the conditions for the first compression molding include: the first compression molding temperature is 100 - 105 °C, the first compression molding time is 10 - 20 min, and the first compression molding pressure is 2 ± 0.5 MPa.

[0034] A preferred embodiment of the present invention, the conditions for the second compression molding include: the second compression molding temperature is 120 - 125 °C, the second compression molding time is 5 - 15 min, and the second compression molding pressure is 5 ± 0.5 MPa.

[0035] A preferred embodiment of the present invention, the conditions for the third compression molding include: the third compression molding temperature is 135 - 140 °C, the third compression molding time is 20 - 30 min, and the third compression molding pressure is 10 ± 0.5 MPa.

[0036] A preferred embodiment of the present invention, in step (3), before the first compression molding, the preform is heated to the first compression molding temperature at a rate of 0.5 - 1 °C / min.

[0037] A preferred embodiment of the present invention, in step (3), before the second compression molding, the material treated by the first compression molding is heated from the first compression molding temperature to the second compression molding temperature at a rate of 0.5 - 1 °C / min.

[0038] A preferred embodiment of the present invention, in step (3), before the third compression molding, the material treated by the second compression molding is heated from the second compression molding temperature to the third compression molding temperature at a rate of 0.5 - 1 °C / min.

[0039] A preferred embodiment of the present invention, before performing step (3), the preform is preheated.

[0040] A preferred embodiment of the present invention, the conditions for the preheating include: the preheating temperature is 80 - 90 °C, and the preheating time is 20 - 40 min.

[0041] A preferred embodiment of the present invention, in step (3), the method for the overall compression molding further includes cooling the fishplate obtained after the third compression molding from the third compression temperature to 80 - 90 °C at a rate of 0.5 - 1.5 °C / min.

[0042] In a third aspect, the present invention provides a rail insulating joint, which includes a rail end insulating member 1, the fishplate 2 described in the first aspect or the fishplate 2 prepared by the preparation method described in the second aspect, a locknut 3, a bolt spacer 4, an inner spacer 5, a flat washer 6, a bolt 7, and a sleeve 8.

[0043] Compared with the prior art, a fishplate, a preparation method thereof and a rail insulating joint according to the present invention have the following beneficial effects:

[0044] (1) The fishplate of the present invention has excellent comprehensive mechanical properties, including excellent bending resistance (up to more than 910 KN) and fatigue resistance (up to more than 2×10 6 times or more), and high overall shear strength (up to more than 510 KN).

[0045] (2) The fishplate provided by the present invention has excellent overall insulation performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a sectional view of a rail insulating joint. DETAILED DESCRIPTION OF THE INVENTION

[0047] The following is to specifically describe the preferred embodiments of the present invention to explain the principle of the present invention, and is not used to limit the scope of the present invention.

[0048] The materials used in the following examples and comparative examples are specifically as follows:

[0049] Bisphenol A epoxy resin (viscosity 12000 - 15000 mPa·s): purchased from South Asia New Materials Co., Ltd., with the brand name NPEL-128;

[0050] Bisphenol A epoxy resin (viscosity 8000 - 11000 mPa·s): purchased from Baling Petrochemical Co., Ltd., with the brand name E54

[0051] Carboxyl-terminated butadiene acrylonitrile rubber: purchased from Tianyuan Aerospace Materials (Yingkou) Technology Co., Ltd., with the brand name TY-CTBN25;

[0052] Aromatic urea epoxy curing agent (particle size 10 μm): purchased from Degussa Chemical (Shanghai) Co., Ltd., with the brand name ecure20;

[0053] Aromatic urea epoxy curing agent (particle size 15 μm): purchased from Degussa Chemical (Shanghai) Co., Ltd., with the brand name ecure30;

[0054] Aramid fiber (para-aramid fiber, breaking strength > 30 cN / dtex, initial modulus > 70 N / tex): purchased from Sinopec Yizheng Chemical Fiber Co., Ltd., with the brand name 1414;

[0055] Glass fiber (tensile modulus 90 GPa): purchased from China National Bluestar (Group) Co., Ltd., with the brand name E7;

[0056] Glass fiber (tensile modulus 95 GPa): purchased from China National Bluestar (Group) Co., Ltd., with the brand name E8.

[0057] Preparation Example 1

[0058] Step (1): Mix 10 kg of bisphenol A epoxy resin (viscosity 12,000 - 15,000 mPa·s), 2.5 kg of diglycidyl 4,5-epoxycyclohexane-1,2-dicarboxylate, and 3 kg of carboxyl-terminated nitrile rubber and stir evenly. Then add 0.7 kg of aromatic urea-based epoxy curing agent (particle size 10 μm), continue to stir evenly, and then mill twice through a three-roll mill to obtain a matrix material;

[0059] Step (2): Preparation of 33.8 kg of multi-axial fiber cloth: a) Mix glass fiber and aramid fiber as the yarn for yarn arrangement according to a weight ratio of 5:1; b) Arrange the first yarn with a yarn arrangement spacing of 6 mm and an arrangement pattern of arranging one and leaving one; c) Arrange the second yarn on the upper layer of the first yarn with an arrangement direction perpendicular to the first yarn and a yarn arrangement spacing of 3 mm; d) Arrange the third yarn on the upper layer of the second yarn. The third yarn is arranged within the spaces formed by the arrangement of the first yarn, with an arrangement direction parallel to the first yarn and a yarn arrangement spacing of 6 mm and an arrangement pattern of arranging one and leaving one; e) The third yarn moves downward and the first yarn moves upward, with both moving heights of 8 mm to pull the second yarn to form an opening of 14.5 mm; f) Use a yarn feeding device to introduce the target yarn to be introduced into the opening channel with a projection angle α of 30° and a height angle β of 0° to complete the introduction of this axial yarn; g) Use a yarn feeding device to introduce the target yarn to be introduced into the opening channel with a projection angle α of 45° and a height angle β of 0° to complete the introduction of this axial yarn; h) Use a yarn feeding device to introduce the target yarn to be introduced into the opening channel with a projection angle α of 60° and a height angle β of 0° to complete the introduction of this axial yarn; i) Make the first yarn and the third yarn return to their original positions to complete the weaving of a 0° / 30° / 45° / 60° / 90° multi-axial fabric (the areal weight of the obtained multi-axial fiber cloth is 1200 g / m 2 , made of a mixture of glass fiber and aramid fiber; among them, the areal weight of the glass fiber is 1000 g / m 2 , the tensile modulus is 90 GPa; the areal weight of the aramid fiber is 200 g / m 2 , the breaking strength > 30 cN / dtex, the initial modulus > 70 N / tex); Immerse the obtained multi-axial fiber cloth with the matrix material to obtain a laminate including an epoxy resin prepreg (thickness 2 mm);

[0060] Step (3): Place the obtained laminate including the epoxy resin prepreg into a flat mold and press and cure at 140 °C and 3 MPa for 15 min to obtain a composite material for performance testing.

[0061] Preparation Example 2

[0062] Step (1): Mix 10 kg of bisphenol A epoxy resin (viscosity 8000 - 11000 mPa·s), 2.5 kg of triglycidyl p-aminophenol, and 2.5 kg of carboxyl-terminated nitrile rubber and stir evenly. Then add 0.6 kg of aromatic urea epoxy curing agent (particle size 10 μm), continue to stir evenly, and then mill twice through a three-roll mill to obtain a matrix material;

[0063] Step (2): Preparation of 29.4 kg of multi-axial fiber cloth (mix glass fiber and aramid fiber in a weight ratio of 3:1 as the yarn for warping to prepare a four-axial fabric, and the preparation method is the same as that in Preparation Example 1; the areal weight of the obtained multi-axial fiber cloth is 1200 g / m 2 , which is made by mixing glass fiber and aramid fiber; among them, the areal weight of glass fiber is 900 g / m 2 , the tensile modulus is 90 GPa; the areal weight of aramid fiber is 300 g / m 2 , the breaking strength > 30 cN / dtex, and the initial modulus > 70 N / tex); Immerse the obtained multi-axial fiber cloth with the matrix material to obtain a laminate (thickness 2 mm) containing epoxy resin prepreg;

[0064] Step (3): Put the obtained laminate containing epoxy resin prepreg into a flat die, press and cure at 140 °C and 3 MPa for 15 min to obtain a composite material for performance testing.

[0065] Preparation Example 3

[0066] Step (1): Mix 10 kg of bisphenol A epoxy resin (viscosity 8000 - 11000 mPa·s), 3.5 kg of diglycidyl 4,5-epoxycyclohexane-1,2-dicarboxylate, and 3.5 kg of carboxyl-terminated nitrile rubber and stir evenly. Then add 0.85 kg of aromatic urea epoxy curing agent (particle size 15 μm), continue to stir evenly, and then mill twice through a three-roll mill to obtain a matrix material;

[0067] Step (2): Preparation of 29.15 kg of multi-axial fiber cloth (mix glass fiber and aramid fiber in a weight ratio of 17:7 as the yarn for warping, and the preparation method is the same as that in Preparation Example 1; the areal weight of the obtained multi-axial fiber cloth is 1200 g / m 2 , which is made by mixing glass fiber and aramid fiber; among them, the areal weight of glass fiber is 850 g / m 2 , the tensile modulus is 90 GPa; the areal weight of aramid fiber is 350 g / m 2, the breaking strength > 30 cN / dtex, the initial modulus > 70 N / tex); The prepared multi-axial fiber cloth is infiltrated with the matrix material to obtain a laminate (with a thickness of 2 mm) containing epoxy prepreg;

[0068] Step (3): Put the prepared laminate containing epoxy prepreg into a flat die, and press and cure it at 140 °C and 3 MPa for 15 min to obtain a composite material for performance testing.

[0069] Example 1

[0070] Step (S1): Cut the laminate containing epoxy prepreg prepared in step (2) of Preparation Example 1 according to the shape of the fishplate, and then lay up the cut laminate according to the thickness (46 mm thickness) and shape of the fishplate to obtain a preform (the total content of glass fiber and aramid fiber along the length direction of the fishplate is 80%);

[0071] Step (S2): Put the obtained preform into a preheated (preheating temperature is 80 °C) fishplate die, close the die, and keep warm for 35 min;

[0072] Step (S3): Then raise the temperature to 100 °C at a heating rate of 0.5 °C / min, and keep warm at 2 MPa for 20 min for the first compression molding; then raise the temperature to 120 °C at a heating rate of 0.5 °C / min, and keep warm at 5 MPa for 10 min for the second compression molding; then raise the temperature to 135 °C at a heating rate of 0.5 °C / min, and keep warm at 10 MPa for 30 min for the third compression molding; then cool down to 80 °C at a cooling rate of 1 °C / min, and open the die to take out the formed fishplate.

[0073] Example 2

[0074] Step (S1): Cut the laminate containing epoxy prepreg prepared in step (2) of Preparation Example 2 according to the shape of the fishplate, and then lay up the cut laminate according to the thickness (46 mm thickness) and shape of the fishplate to obtain a preform (the total content of glass fiber and aramid fiber along the length direction of the fishplate is 75%);

[0075] Step (S2): Put the obtained preform into a preheated (preheating temperature is 90 °C) fishplate die, close the die, and keep warm for 20 min;

[0076] Then, it is heated at a heating rate of 1 °C / min to 100 °C, and kept at 2 MPa for 10 min for the first compression molding; then it is heated at a heating rate of 1 °C / min to 125 °C, and kept at 5 MPa for 10 min for the second compression molding; then it is heated at a heating rate of 1 °C / min to 145 °C, and kept at 10 MPa for 20 min for the third compression molding; then it is cooled at a cooling rate of 1 °C / min to 80 °C, and the mold is opened to take out the well-formed fishplate.

[0077] Example 3

[0078] Step (S1): Cut the laminate including the epoxy resin prepreg obtained in step (2) of Preparation Example 2 according to the shape of the fishplate, and then lay up the cut laminate according to the thickness (46 mm thickness) and shape of the fishplate to obtain a preform (the total content of glass fiber and aramid fiber in the length direction of the fishplate is 75%);

[0079] Step (S2): Put the obtained preform into a preheated (preheating temperature is 85 °C) fishplate mold, close the mold, and keep warm for 25 min;

[0080] Then, it is heated at a heating rate of 1 °C / min to 100 °C, and kept at 2 MPa for 15 min for the first compression molding; then it is heated at a heating rate of 1 °C / min to 120 °C, and kept at 5 MPa for 10 min for the second compression molding; then it is heated at a heating rate of 1 °C / min to 140 °C, and kept at 10 MPa for 25 min for the third compression molding; then it is cooled at a cooling rate of 1 °C / min to 80 °C, and the mold is opened to take out the well-formed fishplate.

[0081] Test Example 1

[0082] The performance test composites prepared in Preparation Examples 1-3 were respectively subjected to the following performance tests, and the test results are shown in Table 1.

[0083] (1) Impact strength: An index to measure the toughness of the material. The impact strength test is carried out according to the determination of the impact performance of plastics by simply supported beam - Part 1: Non - instrumented impact test method of GB / T 1043.1 - 2008; the impact strength specimen adopts a type 1 non - notched specimen, with lateral impact, and the impact angle is perpendicular to the main fiber direction in the specimen (the main fiber direction refers to the arrangement direction with the largest proportion in the multi - axial fiber cloth);

[0084] (2) Flexural strength: The flexural strength test is carried out according to the test method for flexural properties of plastics of GB / T 9341 - 2008;

[0085] (3) Tensile strength and elongation at break: According to the determination of tensile properties of plastics of GB / T 1040 - 2008;

[0086] (4) Density: It refers to the mass per unit volume of the material in the absolutely dense state and is calculated by the following formula: m / v, where m is the mass of the material in the dry state (g), and v is the volume of the material in the absolutely dense state;

[0087] (5) Heat deflection temperature under load: According to GB / T 1634.2-2019 Plastics - Determination of heat deflection temperature under load - Part 2: Plastics and hard rubbers.

[0088] Test Example 2

[0089] The fishplates prepared in Examples 1 - 3 were respectively subjected to the following performance tests, and the test results are shown in Table 2.

[0090] (1) Fishplate insulation performance test: (Conducted with reference to "TBT 2975 - 2018 Rail Bonded Insulated Joints")

[0091] During the test, the test piece should be in a dry state and placed on a dry insulator.

[0092] Insulation resistance test in dry state. Use a 500V megohmmeter to measure the resistance values between the two rails and between the rail and the fishplate.

[0093] Insulation resistance test in wet state. Pour 2L of water at the end plate, and use a multimeter not less than 10V to measure the resistance values between the two rails and between the rail and the fishplate within 1 min - 2 min.

[0094] (2) Fishplate static bending test:

[0095] The length of the fishplate to be tested is 1.2m, and the center of the joint rail gap should be located at the center of the test piece. The test piece is placed on supports with a span of 1000mm, the rail gap is centered, and a concentrated load is applied at the center of the rail gap. During the test, load is applied vertically along the joint, and the loading rate is not greater than 20kN / s. When the specified load is reached, it is stabilized for 30s.

[0096] (3) Fishplate overall shear test: (Conducted with reference to "TBT 2975 - 2018 Rail Bonded Insulated Joints")

[0097] The overall insulated joint test piece should be tested after the bolts are tightened to the specified torque. Saw the test piece into two pieces respectively along the end plate in the middle of the insulated joint test piece and 30mm - 50mm outside the end of the fishplate (the end face slope deviation does not exceed 0.2mm). During the test, load is applied longitudinally along the rail, and the loading speed is not greater than 10kN / s. Each time the load is increased by 150kN, stay for 5s, and then increase the load. When the specified load is reached, it is stabilized for 30s.

[0098] (4) Fishplate fatigue test: (Conducted in reference to "TBT 2975-2018 Rail Bonded Insulated Joints"), and the total number of reciprocating loadings is shown in Table 2.

[0099] Table 1

[0100] Test item Example 1 Example 2 Example 3 <![CDATA[Density (g / cm 3 )]]> 1.95 1.91 1.88 <![CDATA[Impact strength (KJ / m 2 )]]> 553 561 572 Flexural strength (MPa) 1295 1242 1206 Flexural modulus (GPa) 38 36 36 Tensile strength (MPa) 1168 1158 1065 Tensile modulus (GPa) 49 47 46 Elongation at break (%) 2.2 2.4 2.5 Heat distortion temperature under load (°C) 260 250 250 Binder content, % 28.5 28.2 27.9

[0101] Table 2

[0102]

[0103]

[0104] As can be seen from Table 1, the composite materials prepared in Preparation Examples 1-3 have good mechanical properties and relatively high composite heat distortion temperatures.

[0105] As can be seen from Table 2, the fishplates prepared in Examples 1-3 adopting the preferred technical solutions of the present invention have better mechanical properties. The static bending test can reach over 910 KN, the overall shear strength can reach over 510 KN, and the fatigue strength can reach 2×10 6 times or more, and also have good insulation properties (the insulation resistance (dry) can reach 500 MΩ, and the insulation resistance (wet) can reach 100 MΩ).

[0106] It should be noted that the above-described embodiments are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described by referring to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words rather than limiting words. Modifications can be made to the present invention within the scope of the claims of the present invention as stipulated, and the present invention can be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein. On the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. A fishplate, characterized in that, The fishplate is prepared by compression molding a laminate containing an epoxy prepreg; Among them, the epoxy prepreg includes 60-70 wt% of reinforcing material and 30-40 wt% of matrix material; The reinforcing material is a multi-axial fiber cloth. Based on the total amount of the multi-axial fiber cloth, the multi-axial fiber cloth includes 70-85 wt% of glass fiber and 15-30 wt% of aramid fiber.

2. The fishplate according to claim 1, wherein, The epoxy prepreg includes 62-68 wt% of reinforcing material and 32-38 wt% of matrix material.

3. The fishplate according to claim 1 or 2, characterized in that, The surface gram weight of the multi-axial fiber cloth is 1000 - 2200 g / m 2 , preferably 1200 - 1800 g / m 2 ; And / or, the tensile modulus of the glass fiber > 90 GPa, preferably 95-97 GPa; And / or, the breaking strength of the aramid fiber > 30 cN / dtex, and the initial modulus > 70 N / tex; Preferably, the aramid fiber is para-aramid fiber.

4. The fishplate according to any one of claims 1-3, characterized in that The matrix material includes epoxy resin; Preferably, the epoxy resin includes 100 parts by weight of bisphenol A epoxy resin, 20-50 parts by weight of alicyclic epoxy resin, 20-40 parts by weight of epoxy toughening resin, and 3-15 parts by weight of epoxy curing agent; Preferably, the epoxy resin includes 100 parts by weight of bisphenol A epoxy resin, 25-45 parts by weight of alicyclic epoxy resin, 25-35 parts by weight of epoxy toughening resin, and 4-12 parts by weight of epoxy curing agent; Preferably, the viscosity of the bisphenol A epoxy resin is 8000-15000 mPa·s; And / or, the alicyclic epoxy resin is selected from at least one of diglycidyl 4,5-epoxycyclohexane-1,2-dicarboxylate, 4,4-diaminodiphenylmethane tetraglycidylamine, and triglycidyl p-aminophenol, preferably diglycidyl 4,5-epoxycyclohexane-1,2-dicarboxylate and / or triglycidyl p-aminophenol; And / or, the epoxy toughening resin is a carboxyl-terminated liquid nitrile rubber; And / or, the epoxy curing agent is an aromatic urea epoxy curing agent; And / or, the particle size of the epoxy curing agent is 2-20 μm, preferably 5-15 μm.

5. The fishplate according to any one of claims 1-4, characterized in that, The thickness of the laminate is 40-60 mm, preferably 45-55 mm; And / or, the total content of glass fiber and aramid fiber extending along the length direction of the fishplate in the fishplate is 70-95 wt%, preferably 75-90 wt%.

6. The preparation method of the fishplate according to any one of claims 1-5, characterized in that, The preparation method includes the following steps: Step (1): Mix and impregnate the reinforcing material and the matrix material to obtain a laminate containing an epoxy prepreg; Step (2): Cut the obtained laminate containing the epoxy prepreg and lay it according to the shape and thickness of the fishplate to obtain a preform; Step (3): Compression mold the obtained preform to obtain the fishplate.

7. The preparation method according to claim 6, characterized in that, In step (1), before mixing the reinforcing material and the matrix material, under stirring conditions, add the epoxy curing agent to the mixture of bisphenol A epoxy resin, alicyclic epoxy resin, and epoxy toughening resin, stir evenly and grind to obtain the matrix material; And / or, in step (2), the method further includes putting the obtained preform into a preheated mold, closing the mold, and keeping warm; Preferably, in step (2), the temperature for heat preservation is 80 - 90 °C, and the heat preservation time is 20 - 40 min.

8. The preparation method according to claim 6 or 7, characterized in that, In step (3), the method of compression molding includes subjecting the preform to first compression molding, second compression molding, and third compression molding in sequence; Preferably, the conditions for the first compression molding include: the first compression molding temperature is 100 - 105 °C, the first compression molding time is 10 - 20 min, and the first compression molding pressure is 2 ± 0.5 MPa; And / or, the conditions for the second compression molding include: the second compression molding temperature is 120 - 125 °C, the second compression molding time is 5 - 15 min, and the second compression molding pressure is 5 ± 0.5 MPa; And / or, the conditions for the third compression molding include: the third compression molding temperature is 135 - 140 °C, the third compression molding time is 20 - 30 min, and the third compression molding pressure is 10 ± 0.5 MPa.

9. The preparation method according to any one of claims 6-8, characterized in that, In step (3), before the first compression molding, the preform is heated to the first compression molding temperature at a rate of 0.5 - 1 °C / min; And / or, in step (3), before the second compression molding, the material obtained by the first compression molding treatment is heated from the first compression molding temperature to the second compression molding temperature at a rate of 0.5 - 1 °C / min; And / or, in step (3), before the third compression molding, the material obtained by the second compression molding treatment is heated from the second compression molding temperature to the third compression molding temperature at a rate of 0.5 - 1 °C / min; And / or, before step (3), the preform is preheated; Preferably, the conditions for the preheating include: the preheating temperature is 80 - 90 °C, and the preheating time is 20 - 40 min; And / or, in step (3), the method of the overall compression molding further includes cooling the fishplate obtained after the third compression molding from the third compression molding temperature to 80 - 90 °C at a rate of 0.5 - 1.5 °C / min.

10. A rail insulating joint, characterized in that, The rail insulating joint includes a rail end insulating member (1), the fishplate according to any one of claims 1 - 5 or the fishplate prepared by the preparation method according to any one of claims 6 - 9 (2), a lock nut (3), a bolt backing plate (4), an inner backing plate (5), a flat washer (6), a bolt (7), and a sleeve (8).

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