A high-strength and low-stiffness rubber elastic pad under a tie plate and its preparation method

Abstract

The present invention belongs to the technical field of railway switch fasteners, and provides a high-strength and low-stiffness rubber elastic pad under the iron pad and a preparation method thereof. The raw materials include, by weight: 65-75 parts of natural rubber, 25-35 parts of cis-butadiene rubber, 38-46 parts of carbon black, 22-28 parts of white carbon black, 5-7 parts of zinc oxide, 2-4 parts of stearic acid, 3-5 parts of antioxidant, 2-6 parts of coupling agent, 1-3 parts of microcrystalline wax, 3-5.4 parts of accelerator, and 1-3 parts of masterbatch S-80; the coupling agent is composed of 1-3 parts of 3-octanoylthio-1-propyltriethoxysilane and 1-3 parts of ethyltrimethoxysilane. The method provided by the present invention reduces the production cost of the elastic pad, and at the same time, the elastic pad has the advantages of high strength and low stiffness.

Description

Technical Field

[0001] The present invention belongs to the technical field of railway switch fasteners, and relates to a rubber elastic pad under a high-strength and low-stiffness tie plate and a preparation method thereof. Background Art

[0002] The elastic pad under the tie plate is a key component of railway fasteners and is widely used in heavy-haul railways at home and abroad. It is used to provide track elasticity, buffer the high-speed impact vibration generated when the vehicle passes through the rail, and protect the subgrade and sleepers. The elastic pad under the tie plate is mostly prepared by injection molding of thermoplastic polyester elastomer material (TPEE), which has excellent chemical stability and good processability. However, TPEE is expensive and prone to an increase in static stiffness during long-term storage, resulting in insufficient shock absorption effect for the train, inability to effectively reduce noise and vibration, and greater impact and vibration on the train.

[0003] In the prior art, in addition to thermoplastic polyester elastomer (TPEE), rubber materials, polyurethane (PU), and thermoplastic polyurethane elastomer (TPU) are also widely used; rubber is an ideal material selection due to its low cost, good shock absorption effect, and excellent weather resistance, but there are also some deficiencies in actual applications: the strength is not high enough, and the static stiffness may also increase during long-term storage, affecting its shock absorption effect. Summary of the Invention

[0004] The present invention provides a rubber elastic pad under a high-strength and low-stiffness tie plate and a preparation method thereof, which reduce the production cost of the elastic pad and have the advantages of high strength and low stiffness.

[0005] The technical solution of the present invention is realized as follows:

[0006] A rubber elastic pad under a high-strength and low-stiffness tie plate, the raw materials by weight include: 65-75 parts of natural rubber, 25-35 parts of cis-butadiene rubber, 38-46 parts of carbon black, 22-28 parts of white carbon black, 5-7 parts of zinc oxide, 2-4 parts of stearic acid, 3-5 parts of antioxidant, 2-6 parts of coupling agent, 1-3 parts of microcrystalline wax, 3-5.4 parts of accelerator, 1-3 parts of masterbatch S-80; the coupling agent consists of 1-3 parts of 3-octanoylthio-1-propyltriethoxysilane and 1-3 parts of ethyltrimethoxysilane; the accelerator is selected from two or more of accelerator TMTD, accelerator NOBS, accelerator MBTS, and accelerator DPTT.

[0007] Preferably, the coupling agent consists of 2 parts of 3-octanoylthio-1-propyltriethoxysilane and 2 parts of ethyltrimethoxysilane.

[0008] Preferably, the carbon black consists of 19 - 23 parts of carbon black N330 and 19 - 23 parts of carbon black N650.

[0009] Preferably, the anti - aging agent is selected from one or more of anti - aging agent AW, anti - aging agent 4020, and anti - aging agent H71.

[0010] Preferably, the anti - aging agent consists of 1 - 2 parts of anti - aging agent AW, 1 - 2 parts of anti - aging agent 4020, and 1 - 2 parts of anti - aging agent H71.

[0011] Preferably, the accelerator consists of 0.2 - 0.4 parts of accelerator TMTD, 1 - 3 parts of accelerator NOBS, 1 - 2 parts of accelerator MBTS, and 0.2 - 0.6 parts of accelerator DPTT.

[0012] The preparation method of the above - mentioned high - strength and low - stiffness rubber elastic pad under the iron tie plate includes the following steps:

[0013] A. Prepare materials;

[0014] B. Plasticate natural rubber, and after standing for 3 - 5 hours, co - plasticate it with cis - butadiene rubber;

[0015] Then add silica, carbon black, zinc oxide, stearic acid, microcrystalline wax, anti - aging agent, and coupling agent for mixing. When the temperature reaches 110 - 120 °C, discharge the material;

[0016] C. Add the material discharged in step B to the open mill. Let the rubber compound fall onto the tray naturally once, and then cut it with a knife and let it fall onto the tray once. Add the accelerator and masterbatch S - 80, adding them close to the rubber surface and adding them evenly back and forth in an S - shape. Finally, add all the remaining material in the basin along the roll surface. After adding, roll the remaining rubber compound onto the roll, cut it with a knife and let it fall onto the tray once, and let it fall onto the tray naturally once; Adjust the roll gap to 0.4 - 1.6 mm, then pass the rubber sheet thinly once, make a triangular wrap, pass it thinly once again, adjust the roll gap and add rubber, and then take off the sheet;

[0017] After taking off the sheet, let it stand for 24 - 28 h, and make the standing - after mixing rubber compound into a rubber embryo.

[0018] D. Place the rubber embryo obtained in step C in a flat vulcanizer for vulcanization. After vulcanization, obtain the finished product; among them, the vulcanization temperature is 150 - 160 °C, the vulcanization time is 10 - 12 min, and the vulcanization pressure is 15 - 17 MPa.

[0019] Preferably, in step B, first pre - emulsify the coupling agent, mix silica with an ethanol solution, and perform ultrasonic oscillation; then when heating the temperature to 75 - 85 °C, adjust the pH value to 4 - 6; when the temperature is stable at 83 - 87 °C, drop - add the pre - emulsified coupling agent. After the drop - addition is completed, stir and react at a rate of 200 - 300 rpm for 3 - 5 h, and age for 1.5 - 2.5 h; then wash, filter by suction, and dry to obtain silica powder;

[0020] Plasticate natural rubber, and then mix it with cis-butadiene rubber after standing for 3 - 5 hours;

[0021] Then add silica powder, carbon black, zinc oxide, stearic acid, microcrystalline wax and antioxidant for mixing. Discharge the material when the temperature reaches 110 - 120 °C;

[0022] The dosage relationship between the silica and the ethanol solution is 20 - 30 g: 180 - 250 mL; the ethanol solution is an ethanol aqueous solution with a mass fraction of 90%.

[0023] Preferably, the specific conditions for plasticating in step B are as follows: temperature is 130 - 140 °C, time is 240 s - 340 s, the pressure of the upper plug is 6 - 8 kg / cm², and the rotation speed is 30 - 40 rpm;

[0024] Preferably, the specific conditions for mixing are as follows: temperature is 70 - 80 °C, time is 110 - 120 s, the pressure of the upper plug is 6 - 8 kg / cm²;

[0025] Preferably, the specific conditions for mixing are as follows: rotation speed is 15 - 20 rpm, and the mixing time is 480 s - 720 s.

[0026] Preferably, the specific steps of pre-emulsification include: adding a coupling agent to deionized water, stirring at a rate of 500 - 1000 rpm, then dropping the emulsifier dodecylphenol polyoxyethylene ether (OP-10). The dosage of the emulsifier is 5% - 20% of the mass of the coupling agent, and continue stirring for 5 - 10 min to form a stable pre-emulsion;

[0027] Preferably, the specific conditions for ultrasonic oscillation are as follows: time is 30 - 50 min, ultrasonic power is 180 - 250 W, and ultrasonic frequency is 33 - 40 kHz;

[0028] Preferably, glacial acetic acid is used to adjust the pH value;

[0029] Preferably, anhydrous ethanol is used for washing;

[0030] Preferably, the specific conditions for drying are as follows: put it into a vacuum drying oven at 85 - 95 °C and dry for 8 - 12 h.

[0031] The working principle and beneficial effects of the present invention are as follows:

[0032] 1. In the present invention, rubber is used instead of TPEE. Natural rubber and cis-butadiene rubber are used as the main rubber types. By adding large materials such as carbon black and silica, its reinforcing performance is enhanced. Adding medium materials such as antioxidants improves the aging performance of the elastic pad under the tie plate. Adding small materials such as accelerators improves the vulcanization efficiency. The overall coordination of the formula makes the pad have the characteristics of high strength and low static stiffness.

[0033] 2. In the present invention, 3-octanoylthio-1-propyltriethoxysilane and ethyltrimethoxysilane are used in combination with other components. After adding ethyltrimethoxysilane for modification, it is connected to the rubber matrix in a physical entanglement manner. 3-octanoylthio-1-propyltriethoxysilane has strong anti-scorch ability, which improves the dispersion of silica in the rubber compound. When the two are used in combination, a part of the sulfur element in the molecular structure can break the chain to generate free sulfur, which participates in vulcanization crosslinking, and a part participates in the chain hanging reinforcement of silica to form a single-chain structure, improving the mechanical strength of the rubber, while also improving the wear resistance and compression properties of the rubber and reducing the viscosity of the rubber compound. Further, the present invention uses a method of modifying silica with a coupling agent. Compared with the method of direct in-situ grafting, the coupling agent can react with the hydroxyl groups on the surface of silica and interact with the rubber molecular chains, making the silica more evenly dispersed in the rubber and enhancing the interfacial bonding force. During the stretching process, stress can be more effectively transmitted and dispersed through silica, thereby improving the tensile strength of the rubber.

[0034] 3. In the present invention, carbon black is used as a filler to improve the strength of the rubber elastic pad. Among them, commercially available carbon black grades can be used, such as carbon black N330, carbon black N650 or carbon black N330. However, if only one type of carbon black, such as carbon black N330, is used, its resistance is not large enough to meet the usage requirements of the rubber pad under the iron pad. If carbon black N330 and carbon black N650 are used simultaneously, not only the strength of the rubber elastic pad is improved, but also its resistance meets the specific usage requirements of the rubber pad. Detailed implementation mode

[0035] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

[0036] In the embodiments of the present invention, there are no special restrictions on the sources of various instruments, equipment, raw materials or reagents used. They are all conventional products that can be obtained through regular commercial channels, or can be prepared according to conventional methods well-known to those skilled in the art. Among them, the chemical name of antioxidant AW is ethoxyquinoline; the chemical name of antioxidant 4020 is N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine; the chemical name of antioxidant H71 is N,N'-diphenyl-1,4-phenylenediamine; the chemical name of accelerator TMTD is tetramethylthiuram disulfide; the chemical name of accelerator NOBS is N-(oxydiethylene)-2-benzothiazole sulfenamide; the chemical name of accelerator MBTS is dibenzothiazole disulfide; the chemical name of accelerator DPTT is dipentamethylenethiuram tetrasulfide; the grade of natural rubber can be No. 1, No. 2 or No. 3 smoked sheet rubber. In the following examples and comparative examples, the grade of natural rubber is No. 3 smoked sheet rubber, i.e., 3# smoked sheet rubber; the grade of cis-butadiene rubber is BR9000; the silica is Degussa VN3 from Germany, which is precipitated silica with a CTAB adsorption specific surface area of 138-168 m² / g; the masterbatch S-80 is purchased from Nanjing Foster Technology Co., Ltd., and the effective sulfur content is ≥80%.

[0037] Example 1

[0038] A high-strength and low-stiffness rubber elastic pad under the iron tie plate, the raw materials by weight include: 75 parts of 3# smoked sheet rubber, 25 parts of cis-butadiene rubber, 19 parts of carbon black N330, 19 parts of carbon black N650, 28 parts of silica, 5 parts of zinc oxide, 4 parts of stearic acid, 1 part of antioxidant AW, 1 part of antioxidant 4020, 1 part of antioxidant H71, 4 parts of coupling agent, 3 parts of microcrystalline wax, 0.4 part of accelerator TMTD, 1 part of accelerator NOBS, 1 part of accelerator MBTS, 0.6 part of accelerator DPTT, 1 part of masterbatch S-80; the coupling agent consists of 1 part of 3-octanoylthio-1-propyltriethoxysilane and 3 parts of ethyltrimethoxysilane;

[0039] The preparation method of the above high-strength and low-stiffness rubber elastic pad under the iron tie plate includes the following steps:

[0040] A. Prepare materials as above;

[0041] B. Plasticate the 3# smoked sheet rubber, temperature: 130 °C, time: 240 s, upper plug pressure: 6 kg / cm², rotation speed 30 rpm. After standing for 5 hours, co-knead with cis-butadiene rubber, temperature: 70 °C, time: 110 s, upper plug pressure: 6 kg / cm²;

[0042] Then add silica, carbon black, zinc oxide, stearic acid, microcrystalline wax, antioxidant and coupling agent for kneading, rotation speed 15 rpm, kneading time 480 s, and discharge the material when the temperature reaches 110 °C;

[0043] C. Add the materials discharged in step B to the open mill. Let the rubber compound drop onto the tray naturally once and then use a cutting knife to make it drop onto the tray once. Add the accelerator and masterbatch S-80. When adding, keep it close to the rubber surface and add it evenly back and forth in an "S" shape to prevent dust from rising. Finally, add all the remaining materials in the basin along the roll surface. After adding, roll the remaining rubber compound onto the rolls, use a cutting knife to make it drop onto the tray once, and let it drop onto the tray naturally once. Adjust the roll gap to 0.4 mm, then apply the rubber for one pass of thin passing, make a triangular bale, do one pass of thin passing again, adjust the roll gap and apply the rubber, and then cut into sheets.

[0044] After cutting into sheets, let it stand for 24 h, and then make the kneaded rubber into rubber embryos.

[0045] D. Place the rubber embryos obtained in step C in a flat vulcanizing machine for vulcanization. After vulcanization, finished products are obtained. The vulcanization temperature is 150 °C, the vulcanization time is 10 min, and the vulcanization pressure is 15 MPa.

[0046] Example 2

[0047] A high-strength and low-rigidity rubber elastic pad under an iron tie plate, the raw materials include by weight: 70 parts of No. 3 smoked sheet rubber, 30 parts of cis-butadiene rubber, 21 parts of carbon black N330, 21 parts of carbon black N650, 25 parts of white carbon black, 6 parts of zinc oxide, 3 parts of stearic acid, 1 part of antioxidant AW, 2 parts of antioxidant 4020, 1 part of antioxidant H71, 4 parts of coupling agent, 2 parts of microcrystalline wax, 0.3 part of accelerator TMTD, 2 parts of accelerator NOBS, 1.5 parts of accelerator MBTS, 0.4 part of accelerator DPTT, 2 parts of masterbatch S-80; the coupling agent is composed of 2 parts of 3-octanoylthio-1-propyltriethoxysilane and 2 parts of ethyltrimethoxysilane;

[0048] The preparation method of the above high-strength and low-rigidity rubber elastic pad under an iron tie plate includes the following steps:

[0049] A. Prepare materials as above.

[0050] B. Plasticate the No. 3 smoked sheet rubber at a temperature of 135 °C for a time of 290 s, with an upper plug pressure of 7 kg / cm² and a rotational speed of 35 rpm. After standing for 4 h, co-knead it with cis-butadiene rubber at a temperature of 75 °C for a time of 115 s, with an upper plug pressure of 7 kg / cm²;

[0051] Then add white carbon black, carbon black, zinc oxide, stearic acid, microcrystalline wax, antioxidant and coupling agent for kneading, with a rotational speed of 18 rpm and a kneading time of 600 s. Discharge the materials when the temperature reaches 115 °C.

[0052] C. Add the materials discharged in step B to the open mill. Let the rubber compound drop onto the tray naturally once, then cut and drop onto the tray once. Add the accelerator and masterbatch S-80. When adding, keep close to the rubber surface and add evenly back and forth in an "S" shape to prevent dust from rising. Finally, add all the remaining materials in the basin along the roll surface. After adding, roll the remaining rubber compound onto the roll, cut and drop onto the tray once, and let it drop onto the tray naturally once. Adjust the roll gap to 1 mm, then apply the rubber for one pass of thin passing, make a triangular bale, do one pass of thin passing again, adjust the roll gap and apply the rubber, and then sheet off.

[0053] After sheeting off, let it stand for 24 h, and then make the kneaded rubber into rubber embryos.

[0054] D. Place the rubber embryos obtained in step C in a flat vulcanizer for vulcanization. After vulcanization, the finished products are obtained. The vulcanization temperature is 155 °C, the vulcanization time is 11 min, and the vulcanization pressure is 16 MPa.

[0055] Example 3

[0056] A high-strength and low-rigidity rubber elastic pad under an iron tie plate, the raw materials by weight include: 65 parts of No. 3 smoked sheet rubber, 35 parts of cis-butadiene rubber, 23 parts of carbon black N330, 23 parts of carbon black N650, 22 parts of white carbon black, 7 parts of zinc oxide, 2 parts of stearic acid, 2 parts of antioxidant AW, 2 parts of antioxidant 4020, 1 part of antioxidant H71, 4 parts of coupling agent, 1 part of microcrystalline wax, 0.2 part of accelerator TMTD, 3 parts of accelerator NOBS, 2 parts of accelerator MBTS, 0.2 part of accelerator DPTT, 3 parts of masterbatch S-80; the coupling agent is composed of 3 parts of 3-octanoylthio-1-propyltriethoxysilane and 1 part of ethyltrimethoxysilane;

[0057] The preparation method of the above high-strength and low-rigidity rubber elastic pad under an iron tie plate includes the following steps:

[0058] A. Prepare materials as above;

[0059] B. Plasticate the No. 3 smoked sheet rubber at a temperature of 140 °C for a time of 340 s, with an upper plug pressure of 8 kg / cm² and a rotation speed of 40 rpm. After standing for 5 h, co-knead with cis-butadiene rubber at a temperature of 80 °C for a time of 120 s, with an upper plug pressure of 8 kg / cm²;

[0060] Then add white carbon black, carbon black, zinc oxide, stearic acid, microcrystalline wax, antioxidant and coupling agent for kneading, with a rotation speed of 20 rpm and a kneading time of 720 s. Discharge the materials when the temperature reaches 120 °C;

[0061] C. Add the material from step B to the mixing mill. Let the rubber fall naturally on the plate once, cut it with a knife and let it fall on the plate once. Add the accelerator and masterbatch S-80. When adding, keep close to the rubber surface and add them evenly in an S-shaped manner to prevent them from lifting. Finally, add all the remaining material in the basin along the roller surface. After adding, put the remaining rubber on the roller, cut it with a knife and let it fall naturally on the plate once; adjust the roller gap to 1.6mm, then apply a thin pass on the glue, make a triangle bag, apply a thin pass on the glue, adjust the roller gap, apply glue, and unload the sheet;

[0062] After unloading, the mixed rubber is left to stand for 28 hours, and the rubber blank is made from the rubber after standing;

[0063] D. Place the rubber blank obtained in step C in a flat vulcanizer for vulcanization to obtain a finished product; the vulcanization temperature is 160° C., the vulcanization time is 12 min, and the vulcanization pressure is 17 MPa.

[0064] Example 4

[0065] A high-strength, low-rigidity rubber elastic pad under an iron pad, the raw materials comprising, by weight, 70 parts of 3# smoked rubber, 30 parts of butadiene rubber, 20 parts of carbon black N330, 26 parts of white carbon black, 20 parts of carbon black N650, 6 parts of zinc oxide, 3 parts of stearic acid, 4 parts of antioxidant 4020, 2 parts of coupling agent, 2 parts of microcrystalline wax, 0.3 parts of accelerator TMTD, 2 parts of accelerator NOBS, 1.5 parts of accelerator MBTS, 0.4 parts of accelerator DPTT, and 2 parts of masterbatch S-80; the coupling agent is composed of 1 part of 3-octanoylthio-1-propyltriethoxysilane and 1 part of ethyltrimethoxysilane;

[0066] The method for preparing the rubber elastic pad under the high-strength and low-rigidity iron pad comprises the following steps:

[0067] A. Prepare the materials as above;

[0068] B. Plasticate 3# tobacco sheet rubber at 135°C for 290 seconds, with a top bolt pressure of 7 kg / cm² and a rotation speed of 35 rpm. After standing for 4 hours, plasticate with butadiene rubber at 75°C for 115 seconds and a top bolt pressure of 7 kg / cm².

[0069] Then add white carbon black, carbon black, zinc oxide, stearic acid, microcrystalline wax, antioxidant and coupling agent and mix them at a speed of 18 rpm for 600 s. Discharge the material when the temperature reaches 115°C.

[0070] C. Add the material from step B to the mixing mill. Let the rubber fall naturally on the plate once, cut it off with a knife once, add the accelerator and masterbatch S-80, keep close to the rubber surface when adding, and add them evenly in an S-shaped manner to prevent them from lifting. Finally, add all the remaining material in the basin along the roller surface. After adding, put the remaining rubber on the roller, cut it off with a knife once, and let it fall naturally on the plate once; adjust the roller distance to 1mm, apply a thin pass on the glue, make a triangle bag, apply a thin pass on the glue, adjust the roller distance, apply glue, and unload the sheet;

[0071] After unloading, the mixed rubber is left for 24 hours to be made into rubber blanks;

[0072] D. Place the rubber blank obtained in step C in a flat vulcanizer for vulcanization to obtain a finished product; the vulcanization temperature is 155° C., the vulcanization time is 11 min, and the vulcanization pressure is 16 MPa.

[0073] Example 5

[0074] A high-strength, low-rigidity rubber elastic pad under an iron pad, the raw materials comprising, by weight, 70 parts of 3# smoked rubber, 30 parts of butadiene rubber, 42 parts of carbon black N650, 23 parts of white carbon black, 6 parts of zinc oxide, 3 parts of stearic acid, 1 part of antioxidant AW, 1 part of antioxidant 4020, 2 parts of antioxidant H71, 6 parts of coupling agent, 2 parts of microcrystalline wax, 2 parts of accelerator TMTD, 2 parts of accelerator NOBS, and 2 parts of masterbatch S-80; the coupling agent is composed of 3 parts of 3-octanoylthio-1-propyltriethoxysilane and 3 parts of ethyltrimethoxysilane;

[0075] The method for preparing the rubber elastic pad under the high-strength and low-rigidity iron pad comprises the following steps:

[0076] A. Prepare the materials as above;

[0077] B. Plasticate 3# tobacco sheet rubber at 135°C for 290 seconds, with a top bolt pressure of 7 kg / cm² and a rotation speed of 35 rpm. After standing for 4 hours, plasticate with butadiene rubber at 75°C for 115 seconds and a top bolt pressure of 7 kg / cm².

[0078] Then add white carbon black, carbon black, zinc oxide, stearic acid, microcrystalline wax, antioxidant and coupling agent and mix them at a speed of 18 rpm for 600 s. Discharge the material when the temperature reaches 115°C.

[0079] C. Add the material from step B to the mixing mill. Let the rubber fall naturally on the plate once, cut it off with a knife once, add the accelerator and masterbatch S-80, keep close to the rubber surface when adding, and add them evenly in an S-shaped manner to prevent them from lifting. Finally, add all the remaining material in the basin along the roller surface. After adding, put the remaining rubber on the roller, cut it off with a knife once, and let it fall naturally on the plate once; adjust the roller distance to 1mm, apply a thin pass on the glue, make a triangle bag, apply a thin pass on the glue, adjust the roller distance, apply glue, and unload the sheet;

[0080] After the lower sheet is parked for 24 hours, the parked kneaded rubber is made into a rubber embryo;

[0081] D. Place the rubber embryo obtained in step C in a flat vulcanizer for vulcanization. After vulcanization, the finished product is obtained; the vulcanization temperature is 155 °C, the vulcanization time is 11 minutes, and the vulcanization pressure is 16 MPa.

[0082] Example 6

[0083] A high-strength and low-stiffness rubber elastic pad under the iron tie plate, the raw materials include by weight: 70 parts of No. 3 smoked sheet rubber, 30 parts of cis-butadiene rubber, 21 parts of carbon black N330, 21 parts of carbon black N650, 25 parts of white carbon black, 6 parts of zinc oxide, 3 parts of stearic acid, 1 part of antioxidant AW, 2 parts of antioxidant 4020, 1 part of antioxidant H71, 4 parts of coupling agent, 2 parts of microcrystalline wax, 0.3 part of accelerator TMTD, 2 parts of accelerator NOBS, 1.5 parts of accelerator MBTS, 0.4 part of accelerator DPTT, 2 parts of masterbatch S-80; the coupling agent consists of 2 parts of 3-octanoylthio-1-propyltriethoxysilane and 2 parts of ethyltrimethoxysilane;

[0084] The preparation method of the above high-strength and low-stiffness rubber elastic pad under the iron tie plate includes the following steps:

[0085] A. The material preparation is the same as above;

[0086] B. First, pre-emulsify the coupling agent, mix white carbon black with an ethanol aqueous solution with a mass fraction of 90%, and perform ultrasonic oscillation; then when the temperature is heated to 80 °C, adjust the pH value to 5; when the temperature is stable at 85 °C, dropwise add the pre-emulsified coupling agent. After the dropwise addition, during the reaction process, reflux condensation is carried out, and at the same time, the reaction is stirred at a rate of 250 rpm for 4 hours and aged for 2 hours; then wash, filter by suction, and dry to obtain white carbon black powder;

[0087] Plasticize the No. 3 smoked sheet rubber, temperature: 135 °C, time: 290 s, upper plug pressure: 7 kg / cm², rotation speed 35 rpm. After parking for 4 hours, it is co-kneaded with cis-butadiene rubber, temperature: 75 °C, time: 115 s, upper plug pressure: 7 kg / cm²;

[0088] Then add white carbon black powder, carbon black, zinc oxide, stearic acid, microcrystalline wax and antioxidant for kneading, rotation speed 18 rpm, kneading time 600 s, and discharge the material when the temperature reaches 115 °C;

[0089] The dosage relationship between the white carbon black and the ethanol aqueous solution is 25 g: 220 mL;

[0090] The specific steps of the pre-emulsification include: adding a coupling agent to deionized water while stirring at a rate of 800 rpm, then dropwise adding an emulsifier, dodecylphenol polyoxyethylene ether, in an amount of 10% of the mass of the coupling agent, and continuing stirring for 8 minutes to form a stable pre-emulsion;

[0091] The ultrasonic oscillation is performed for 40 minutes, the ultrasonic power is 200W, and the ultrasonic frequency is 35kHz; glacial acetic acid is used to adjust the pH value; anhydrous ethanol is used for washing; and drying specifically includes: placing in a vacuum drying oven at 90°C for 10 hours;

[0092] C. Add the material from step B to the mixing mill. Let the rubber fall naturally on the plate once, cut it off with a knife once, add the accelerator and masterbatch S-80, keep close to the rubber surface when adding, and add them evenly in an S-shaped manner to prevent them from lifting. Finally, add all the remaining material in the basin along the roller surface. After adding, put the remaining rubber on the roller, cut it off with a knife once, and let it fall naturally on the plate once; adjust the roller distance to 1mm, apply a thin pass on the glue, make a triangle bag, apply a thin pass on the glue, adjust the roller distance, apply glue, and unload the sheet;

[0093] After unloading, the mixed rubber is left for 24 hours to be made into rubber blanks;

[0094] D. Place the rubber blank obtained in step C in a flat vulcanizer for vulcanization to obtain a finished product; the vulcanization temperature is 155° C., the vulcanization time is 11 min, and the vulcanization pressure is 16 MPa.

[0095] Example 7

[0096] A high-strength, low-rigidity rubber elastic pad under an iron pad, comprising, by weight, 70 parts of 3# smoked rubber, 30 parts of butadiene rubber, 21 parts of carbon black N330, 21 parts of carbon black N650, 25 parts of white carbon black, 6 parts of zinc oxide, 3 parts of stearic acid, 1 part of antioxidant AW, 2 parts of antioxidant 4020, 1 part of antioxidant H71, 4 parts of coupling agent, 2 parts of microcrystalline wax, 0.3 parts of accelerator TMTD, 2 parts of accelerator NOBS, 1.5 parts of accelerator MBTS, 0.4 parts of accelerator DPTT, and 2 parts of masterbatch S-80; the coupling agent is composed of 2 parts of 3-octanoylthio-1-propyltriethoxysilane and 2 parts of ethyltrimethoxysilane;

[0097] The method for preparing the rubber elastic pad under the high-strength and low-rigidity iron pad comprises the following steps:

[0098] A. Prepare the materials as above;

[0099] B. First, pre-emulsify the coupling agent. Blend fumed silica with an aqueous ethanol solution with a mass fraction of 90% and perform ultrasonic oscillation. Then, when the heating temperature reaches 75 °C, adjust the pH value to 6. When the temperature stabilizes at 83 °C, dropwise add the pre-emulsified coupling agent. After the addition is complete, during the reaction process, carry out reflux condensation and stir at a rate of 200 rpm for 3 h, and age for 1.5 h. Then, wash, filter by suction, and dry to obtain fumed silica powder.

[0100] Plasticate the No. 3 smoked sheet rubber at a temperature of 135 °C, for a time of 290 s, with an upper plug pressure of 7 kg / cm² and a rotation speed of 35 rpm. After standing for 4 hours, co-knead it with cis-butadiene rubber at a temperature of 75 °C, for a time of 115 s, and an upper plug pressure of 7 kg / cm².

[0101] Then, add the fumed silica powder, carbon black, zinc oxide, stearic acid, microcrystalline wax, and antioxidant for kneading at a rotation speed of 18 rpm and a kneading time of 600 s. Discharge the material when the temperature reaches 115 °C.

[0102] The dosage relationship between the fumed silica and the aqueous ethanol solution is 20 g: 180 mL.

[0103] The specific steps of the pre-emulsification include: add the coupling agent to deionized water and stir at a rate of 500 rpm. Then, dropwise add the emulsifier dodecylphenol polyoxyethylene ether. The dosage of the emulsifier is 20% of the mass of the coupling agent, and continue to stir for 5 min to form a stable pre-emulsion.

[0104] Perform ultrasonic oscillation for 30 min with an ultrasonic power of 180 W and an ultrasonic frequency of 33 kHz. Use glacial acetic acid to adjust the pH value. Wash with absolute ethanol. The drying specifically includes: put it into a vacuum drying oven at 85 °C and dry for 12 h.

[0105] C. Add the material discharged in step B to the open mill. Let the rubber compound fall onto the tray naturally once and cut it onto the tray once. Add the accelerator and masterbatch S-80. When adding, keep it close to the rubber surface and add it evenly back and forth in an S shape to prevent dusting. Finally, add all the remaining material in the basin along the roll surface. After the addition is complete, roll the remaining rubber compound onto the roll, cut it onto the tray once, and let it fall onto the tray naturally once. Adjust the roll gap to 1 mm, then apply the rubber for thin passing once, make a triangular bale, thin pass once, adjust the roll gap to apply the rubber, and take off the sheet.

[0106] After taking off the sheet, let it stand for 24 h, and make the kneaded rubber compound after standing into rubber embryos.

[0107] D. Place the rubber embryos obtained in step C in a flat vulcanizer for vulcanization. After vulcanization is completed, obtain the finished product. The vulcanization temperature is 155 °C, the vulcanization time is 11 min, and the vulcanization pressure is 16 MPa.

[0108] Example 8

[0109] A high-strength and low-stiffness rubber elastic pad under the iron tie plate, the raw materials by weight include: 70 parts of No. 3 smoked sheet rubber, 30 parts of cis-butadiene rubber, 21 parts of carbon black N330, 21 parts of carbon black N650, 25 parts of white carbon black, 6 parts of zinc oxide, 3 parts of stearic acid, 1 part of antioxidant AW, 2 parts of antioxidant 4020, 1 part of antioxidant H71, 4 parts of coupling agent, 2 parts of microcrystalline wax, 0.3 part of accelerator TMTD, 2 parts of accelerator NOBS, 1.5 parts of accelerator MBTS, 0.4 part of accelerator DPTT, 2 parts of masterbatch S-80; the coupling agent consists of 2 parts of 3-octanoylthio-1-propyltriethoxysilane and 2 parts of ethyltrimethoxysilane;

[0110] The preparation method of the above high-strength and low-stiffness rubber elastic pad under the iron tie plate includes the following steps:

[0111] A. Prepare materials as above;

[0112] B. First, pre-emulsify the coupling agent, mix white carbon black with an ethanol aqueous solution with a mass fraction of 90%, and perform ultrasonic oscillation; then when the temperature is heated to 85 °C, adjust the pH value to 4; when the temperature is stable at 87 °C, dropwise add the pre-emulsified coupling agent. After the dropping is completed, during the reaction process, reflux and condense, and at the same time stir at a rate of 300 rpm for 5 h and age for 2.5 h; then wash, filter by suction, and dry to obtain white carbon black powder;

[0113] Plasticize the No. 3 smoked sheet rubber, temperature: 135 °C, time: 290 s, upper plug pressure: 7 kg / cm², rotation speed 35 rpm. After standing for 4 hours, co-knead with cis-butadiene rubber, temperature: 75 °C, time: 115 s, upper plug pressure: 7 kg / cm²;

[0114] Then add white carbon black powder, carbon black, zinc oxide, stearic acid, microcrystalline wax and antioxidant for kneading, rotation speed 18 rpm, kneading time 600 s, and discharge the material when the temperature reaches 115 °C;

[0115] The dosage relationship between the white carbon black and the ethanol aqueous solution is 30 g: 250 mL;

[0116] The specific steps of the pre-emulsification include: add the coupling agent to deionized water, and at the same time stir at a rate of 1000 rpm, then dropwise add the emulsifier dodecylphenol polyoxyethylene ether. The dosage of the emulsifier is 5% of the mass of the coupling agent, and continue to stir for 10 min to form a stable pre-emulsion;

[0117] The ultrasonic oscillation is for 50 min, the ultrasonic power is 250 W, and the ultrasonic frequency is 40 kHz; the pH value is adjusted using glacial acetic acid; the washing is carried out using anhydrous ethanol; the drying specifically includes: drying in a vacuum drying oven at 95 °C for 12 h;

[0118] C. Add the materials in step B to the open mill. Let the rubber compound drop onto the tray naturally once, then use a cutting knife to make it drop onto the tray once. Add the accelerator and masterbatch S-80. When adding, keep it close to the rubber surface and add it evenly back and forth in an "S" shape to prevent dust from rising. Finally, add all the remaining materials in the basin along the roll surface. After adding, roll the remaining rubber compound onto the rolls, use a cutting knife to make it drop onto the tray once, and let it drop onto the tray naturally once. Adjust the roll gap to 1 mm, then apply the rubber for a single pass of thin passing, make a triangular bale, do a single pass of thin passing again, adjust the roll gap and apply the rubber, and then take off the sheet.

[0119] After taking off the sheet, let it stand for 24 h, and then make the kneaded rubber into rubber embryos.

[0120] D. Place the rubber embryos obtained in step C in a flat vulcanizer for vulcanization. After vulcanization, the finished products are obtained. The vulcanization temperature is 155 °C, the vulcanization time is 11 min, and the vulcanization pressure is 16 MPa.

[0121] Comparative Example 1

[0122] A rubber elastic cushion plate, the raw materials by weight include: 70 parts of No. 3 smoked sheet rubber, 30 parts of cis-butadiene rubber, 21 parts of carbon black N330, 21 parts of carbon black N650, 25 parts of white carbon black, 6 parts of zinc oxide, 3 parts of stearic acid, 1 part of antioxidant AW, 2 parts of antioxidant 4020, 1 part of antioxidant H71, 4 parts of coupling agent, 2 parts of microcrystalline wax, 0.3 part of accelerator TMTD, 2 parts of accelerator NOBS, 1.5 parts of accelerator MBTS, 0.4 part of accelerator DPTT, 2 parts of masterbatch S-80; the coupling agent is 3-octanoylthio-1-propyltriethoxysilane;

[0123] The preparation method of the above-mentioned rubber elastic cushion plate under the high-strength and low-rigidity iron cushion plate includes the following steps:

[0124] A. Prepare materials as above.

[0125] B. Plasticate the No. 3 smoked sheet rubber at a temperature of 135 °C for a time of 290 s, with an upper plug pressure of 7 kg / cm² and a rotation speed of 35 rpm. After standing for 4 h, co-knead it with cis-butadiene rubber at a temperature of 75 °C for a time of 115 s and an upper plug pressure of 7 kg / cm².

[0126] Then add white carbon black, carbon black, zinc oxide, stearic acid, microcrystalline wax, antioxidant and coupling agent for kneading, with a rotation speed of 18 rpm and a kneading time of 600 s. Discharge the materials when the temperature reaches 115 °C.

[0127] C. Add the material from step B to the mixing mill. Let the rubber fall naturally on the plate once, cut it off with a knife once, add the accelerator and masterbatch S-80, keep close to the rubber surface when adding, and add them evenly in an S-shaped manner to prevent them from lifting. Finally, add all the remaining material in the basin along the roller surface. After adding, put the remaining rubber on the roller, cut it off with a knife once, and let it fall naturally on the plate once; adjust the roller distance to 1mm, apply a thin pass on the glue, make a triangle bag, apply a thin pass on the glue, adjust the roller distance, apply glue, and unload the sheet;

[0128] After unloading, the mixed rubber is left for 24 hours to be made into rubber blanks;

[0129] D. Place the rubber blank obtained in step C in a flat vulcanizer for vulcanization to obtain a finished product; the vulcanization temperature is 155° C., the vulcanization time is 11 min, and the vulcanization pressure is 16 MPa.

[0130] Comparative Example 2

[0131] A rubber elastic pad, comprising, by weight, 70 parts of 3# smoked rubber, 30 parts of butadiene rubber, 21 parts of carbon black N330, 21 parts of carbon black N650, 25 parts of white carbon black, 6 parts of zinc oxide, 3 parts of stearic acid, 1 part of antioxidant AW, 2 parts of antioxidant 4020, 1 part of antioxidant H71, 4 parts of coupling agent, 2 parts of microcrystalline wax, 0.3 parts of accelerator TMTD, 2 parts of accelerator NOBS, 1.5 parts of accelerator MBTS, 0.4 parts of accelerator DPTT, and 2 parts of masterbatch S-80; the coupling agent is ethyltrimethoxysilane;

[0132] The method for preparing the rubber elastic pad under the high-strength and low-rigidity iron pad comprises the following steps:

[0133] A. Prepare the materials as above;

[0134] B. Plasticate 3# tobacco sheet rubber at 135°C for 290 seconds, with a top bolt pressure of 7 kg / cm² and a rotation speed of 35 rpm. After standing for 4 hours, plasticate with butadiene rubber at 75°C for 115 seconds and a top bolt pressure of 7 kg / cm².

[0135] Then add white carbon black, carbon black, zinc oxide, stearic acid, microcrystalline wax, antioxidant and coupling agent and mix them at a speed of 18 rpm for 600 s. Discharge the material when the temperature reaches 115°C.

[0136] C. Add the material from step B to the mixing mill. Let the rubber fall naturally on the plate once, cut it off with a knife once, add the accelerator and masterbatch S-80, keep close to the rubber surface when adding, and add them evenly in an S-shaped manner to prevent them from lifting. Finally, add all the remaining material in the basin along the roller surface. After adding, put the remaining rubber on the roller, cut it off with a knife once, and let it fall naturally on the plate once; adjust the roller distance to 1mm, apply a thin pass on the glue, make a triangle bag, apply a thin pass on the glue, adjust the roller distance, apply glue, and unload the sheet;

[0137] After the lower sheet, it is parked for 24 h, and the parked mixed rubber is made into rubber embryos;

[0138] D. Place the rubber embryo obtained in step C in a flat vulcanizing machine for vulcanization. After vulcanization, the finished product is obtained; the vulcanization temperature is 155 °C, the vulcanization time is 11 min, and the vulcanization pressure is 16 MPa.

[0139] Comparative Example 3

[0140] A rubber elastic cushion plate, the raw materials by weight include: 70 parts of No. 3 smoked sheet rubber, 30 parts of cis-butadiene rubber, 21 parts of carbon black N330, 21 parts of carbon black N650, 25 parts of white carbon black, 6 parts of zinc oxide, 3 parts of stearic acid, 1 part of antioxidant AW, 2 parts of antioxidant 4020, 1 part of antioxidant H71, 2 parts of microcrystalline wax, 0.3 part of accelerator TMTD, 2 parts of accelerator NOBS, 1.5 parts of accelerator MBTS, 0.4 part of accelerator DPTT, 2 parts of masterbatch S-80;

[0141] The preparation method of the rubber elastic cushion plate under the above high-strength and low-rigidity iron cushion plate includes the following steps:

[0142] A. The material preparation is the same as above;

[0143] B. Plasticate the No. 3 smoked sheet rubber, temperature: 135 °C, time: 290 s, upper plug pressure: 7 kg / cm², rotation speed 35 rpm. After parking for 4 hours, it is co-mixed with cis-butadiene rubber, temperature: 75 °C, time: 115 s, upper plug pressure: 7 kg / cm²;

[0144] Then add white carbon black, carbon black, zinc oxide, stearic acid, microcrystalline wax and antioxidant for mixing, rotation speed 18 rpm, mixing time 600 s, and discharge the material when the temperature reaches 115 °C;

[0145] C. Add the discharged material in step B to an open mill. The rubber material falls onto the tray naturally once and is cut and falls onto the tray once. Add accelerators and masterbatch S-80, add them close to the rubber surface, add them back and forth evenly in an S shape to prevent dust from rising. Finally, add all the remaining material in the basin along the roll surface. After adding, roll the remaining rubber material onto the roll, cut and fall onto the tray once, and fall onto the tray naturally once; adjust the roll gap to 1 mm, then apply the rubber and thin-pass it once, make a triangular package, thin-pass it once, adjust the roll gap and apply the rubber, and then take off the sheet;

[0146] After taking off the sheet, park for 24 h, and make the parked mixed rubber into rubber embryos;

[0147] D. Place the rubber embryo obtained in step C in a flat vulcanizing machine for vulcanization. After vulcanization, the finished product is obtained; the vulcanization temperature is 155 °C, the vulcanization time is 11 min, and the vulcanization pressure is 16 MPa.

[0148] Comparative Example 4

[0149] A rubber elastic pad, comprising the following raw materials by weight: 70 parts of 3# smoked rubber, 30 parts of butadiene rubber, 21 parts of carbon black N330, 21 parts of carbon black N650, 25 parts of white carbon black, 6 parts of zinc oxide, 3 parts of stearic acid, 1 part of antioxidant AW, 2 parts of antioxidant 4020, 1 part of antioxidant H71, 4 parts of coupling agent, 2 parts of microcrystalline wax, 0.3 parts of accelerator TMTD, 2 parts of accelerator NOBS, 1.5 parts of accelerator MBTS, 0.4 parts of accelerator DPTT, and 2 parts of masterbatch S-80; the coupling agent is composed of 2 parts of 3-octanoylthio-1-propyltriethoxysilane and 2 parts of 3-mercaptopropyltrimethoxysilane;

[0150] The method for preparing the rubber elastic pad under the high-strength and low-rigidity iron pad comprises the following steps:

[0151] A. Prepare the materials as above;

[0152] B. Plasticate 3# tobacco sheet rubber at 135°C for 290 seconds, with a top bolt pressure of 7 kg / cm² and a rotation speed of 35 rpm. After standing for 4 hours, plasticate with butadiene rubber at 75°C for 115 seconds and a top bolt pressure of 7 kg / cm².

[0153] Then add white carbon black, carbon black, zinc oxide, stearic acid, microcrystalline wax, antioxidant and coupling agent and mix them at a speed of 18 rpm for 600 s. Discharge the material when the temperature reaches 115°C.

[0154] C. Add the material from step B to the mixing mill. Let the rubber fall naturally on the plate once, cut it off with a knife once, add the accelerator and masterbatch S-80, keep close to the rubber surface when adding, and add them evenly in an S-shaped manner to prevent them from lifting. Finally, add all the remaining material in the basin along the roller surface. After adding, put the remaining rubber on the roller, cut it off with a knife once, and let it fall naturally on the plate once; adjust the roller distance to 1mm, apply a thin pass on the glue, make a triangle bag, apply a thin pass on the glue, adjust the roller distance, apply glue, and unload the sheet;

[0155] After unloading, the mixed rubber is left for 24 hours to be made into rubber blanks;

[0156] D. Place the rubber blank obtained in step C in a flat vulcanizer for vulcanization to obtain a finished product; the vulcanization temperature is 155° C., the vulcanization time is 11 min, and the vulcanization pressure is 16 MPa.

[0157] Performance Testing

[0158] In order to better illustrate the properties of the pad provided by the embodiment of the present invention, the products prepared in the comparative example and the embodiment were tested for corresponding properties according to TB / T 3395.4. The results are shown in Table 1-2.

[0159] Table 1

[0160]

[0161] Table 2

[0162]

[0163] For the rubber pads prepared in Embodiments 1-8 of the present invention, the static stiffness can be maintained below 47 mm / kN after long-term parking (3 months). It can be seen that the overall coordination of the formula of the present invention endows the pads with the characteristics of high strength and low static stiffness.

[0164] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A rubber elastic pad under a high-strength and low-rigidity tie plate, characterized in that, The raw materials are composed of 65 - 75 parts by weight of natural rubber, 25 - 35 parts of cis - 1,4 - polybutadiene rubber, 38 - 46 parts of carbon black, 22 - 28 parts of silica, 5 - 7 parts of zinc oxide, 2 - 4 parts of stearic acid, 3 - 5 parts of anti - aging agent, 2 - 6 parts of coupling agent, 1 - 3 parts of microcrystalline wax, 3 - 5.4 parts of accelerator, and 1 - 3 parts of masterbatch S - 80; the coupling agent is composed of 1 - 3 parts of 3 - octanoylthio - 1 - propyltriethoxysilane and 1 - 3 parts of ethyltrimethoxysilane; the accelerator is selected from two or more of accelerator TMTD, accelerator NOBS, accelerator MBTS, and accelerator DPTT; The carbon black is composed of 19 - 23 parts of carbon black N330 and 19 - 23 parts of carbon black N650; The anti - aging agent is composed of 1 - 2 parts of anti - aging agent AW, 1 - 2 parts of anti - aging agent 4020, and 1 - 2 parts of anti - aging agent H71; The grade of the natural rubber is No. 3 smoked sheet rubber, and the grade of the cis - 1,4 - polybutadiene rubber is BR9000.

2. The rubber elastic pad under the high-strength and low-rigidity tie plate according to claim 1, characterized in that The coupling agent is composed of 2 parts of 3 - octanoylthio - 1 - propyltriethoxysilane and 2 parts of ethyltrimethoxysilane.

3. The rubber elastic pad under the high-strength and low-stiffness tie plate according to claim 1, characterized in that, The accelerator is composed of 0.2 - 0.4 parts of accelerator TMTD, 1 - 3 parts of accelerator NOBS, 1 - 2 parts of accelerator MBTS, and 0.2 - 0.6 parts of accelerator DPTT.

4. The preparation method of the rubber elastic pad under the high-strength and low-rigidity tie plate according to any one of claims 1-3, characterized in that, It includes the following steps: A. Prepare materials; B. Plasticate the natural rubber, and after standing for 3 - 5 hours, co - plasticate it with cis - 1,4 - polybutadiene rubber; Then add silica, carbon black, zinc oxide, stearic acid, microcrystalline wax, anti - aging agent, and coupling agent for mixing. When the temperature reaches 110 - 120 °C, discharge the material; C. Add the material discharged in step B to the open mill. Let the rubber compound fall onto the tray naturally once and cut with a knife and fall onto the tray once. Add the accelerator and masterbatch S - 80. When adding, keep close to the rubber surface and add it evenly back and forth in an S - shape. Finally, add all the remaining material in the basin along the roll surface. After adding, roll the remaining rubber compound onto the roll, cut with a knife and fall onto the tray once, and fall onto the tray naturally once; Adjust the roll gap to 0.4 - 1.6 mm, then apply the rubber thinly and pass it through once, make a triangular package, pass it through thinly once, adjust the roll gap to apply the rubber, and take off the sheet; After taking off the sheet, let it stand for 24 - 28 h, and make the standing - after mixed rubber compound into rubber embryos; D. Place the rubber embryos obtained in step C in a flat vulcanizer for vulcanization. After vulcanization, the finished product is obtained; among them, the vulcanization temperature is 150 - 160 °C, the vulcanization time is 10 - 12 min, and the vulcanization pressure is 15 - 17 MPa.

5. The preparation method of the rubber elastic pad under the high-strength and low-stiffness tie plate according to claim 4, characterized in that, In step B, first pre - emulsify the coupling agent, mix silica with an ethanol solution, and perform ultrasonic oscillation; then when heating the temperature to 75 - 85 °C, adjust the pH value to 4 - 6; when the temperature is stable at 83 - 87 °C, drop - add the pre - emulsified coupling agent. After the dropping is completed, stir and react at a rate of 200 - 300 rpm for 3 - 5 h, and age for 1.5 - 2.5 h; then wash, filter by suction, and dry to obtain silica powder; Plasticate the natural rubber, and after standing for 3 - 5 hours, co - plasticate it with cis - 1,4 - polybutadiene rubber; Then add silica powder, carbon black, zinc oxide, stearic acid, microcrystalline wax, and anti - aging agent for mixing. When the temperature reaches 110 - 120 °C, discharge the material; The dosage relationship between the silica and the ethanol solution is 20 - 30 g : 180 - 250 mL; the ethanol solution is an ethanol aqueous solution with a mass fraction of 90%.

6. The preparation method of the rubber elastic pad under the high-strength and low-rigidity tie plate according to claim 4, characterized in that, The specific conditions for the mastication in step B are as follows: the temperature is 130 - 140 °C, the time is 240 s - 340 s, the pressure of the upper plug is 6 - 8 kg / cm², and the rotation speed is 30 - 40 rpm; The specific conditions for the incorporation are as follows: the temperature is 70 - 80 °C, the time is 110 - 120 s, and the pressure of the upper plug is 6 - 8 kg / cm²; The specific conditions for the mixing are as follows: the rotation speed is 15 - 20 rpm, and the mixing time is 480 s - 720 s.

7. The preparation method of the rubber elastic pad under the high-strength and low-rigidity tie plate according to claim 5, characterized in that, The specific steps of the pre-emulsification include: adding the coupling agent into deionized water, stirring at a rate of 500 - 1000 rpm, then dropping the emulsifier, and the dosage of the emulsifier is 5% - 20% of the mass of the coupling agent, and continuing to stir for 5 - 10 min to form a stable pre-emulsion; The specific conditions for the ultrasonic oscillation are as follows: the time is 30 - 50 min, the ultrasonic power is 180 - 250 W, and the ultrasonic frequency is 33 - 40 kHz; the pH value is adjusted using glacial acetic acid; the washing is carried out using absolute ethanol; the specific conditions for the drying are as follows: placing it in a vacuum drying oven at 85 - 95 °C and drying for 8 - 12 h.

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