High damping polyurethane mat and method of making same

Abstract

The application belongs to the technical field of polyurethane, and particularly relates to a high-damping polyurethane pad and a preparation method thereof. The high-damping polyurethane pad is mainly made of component A and component B, wherein the component A mainly comprises, in weight fractions, 50-80 parts of amine ether polyol, 20-40 parts of polyether polyol and 8-10 parts of ethylene glycol; the component B mainly comprises, in weight fractions, 50-100 parts of PTMG3000, 30-50 parts of PTMG650 and 100-150 parts of isocyanate; the mass ratio of PTMG3000 to PTMG650 in the component B is 1:1-2.5:1; the high-damping polyurethane pad and the preparation method thereof have the advantages that the prepared polyurethane pad has high damping, excellent dynamic performance, good aging resistance and low-temperature adaptability; the application further provides a preparation method, and the preparation process is simple and low in cost.

Description

Technical Field

[0001] This invention belongs to the field of polyurethane technology, specifically relating to high-damping polyurethane pads and their preparation methods. Background Technology

[0002] As high-speed railway speeds increase to 350 km / h and above, the axle load of heavy-haul railways also continues to increase, significantly increasing the impact load between wheels and rails. This places more stringent demands on the damping and vibration reduction performance, durability, and long-term service stability of track buffer pads. As a core vibration damping component in the railway track system, the performance of track buffer pads directly affects the service life of the track structure, train safety, and passenger comfort, and is crucial for ensuring the long-term stable operation of railways under high loads.

[0003] Currently, traditional track buffer pad structures mostly use natural or synthetic rubber as the core material. These rubber pads have inherent defects: high stiffness and insufficient elasticity. Under the long-term action of wheel-rail impact loads, they are difficult to effectively buffer and reduce vibration, which can easily lead to track bed wear, sleeper cracking and other track structure damage. At the same time, they can cause excessive vibration and noise, affecting the surrounding environment and the driving experience. In addition, natural or synthetic rubber pads are easily affected by changes in ambient temperature and humidity during long-term service, and are prone to aging, hardening and cracking. They also have a large permanent compression deformation, and the elasticity decay is particularly obvious in low-temperature environments, resulting in a limited service life. They cannot meet the long-term high-load and complex operating conditions of high-speed railways and heavy-haul railways.

[0004] Polyurethane materials, due to their excellent elasticity, wear resistance, aging resistance, and designability, are widely used in vibration damping and cushioning, becoming a preferred material to replace traditional rubber pads. Several related technologies have been disclosed. For example, patent CN114478972A discloses a high-damping polyurethane elastomer made from a mixture of component A and component B. Component A contains raw materials such as polyether polyol A, polyether polyol B, and vegetable oil polyol, while component B contains raw materials such as polyether polyol C, isophorone diisocyanate, and MDI, and is a prepolymer with an isocyanate content of 15%–22%. This elastomer exhibits high damping properties, has no filler added, and good product stability, making it suitable for vibration damping pad preparation. However, it does not consider the key properties required for pads under wheel-rail impact loads, such as resistance to permanent compression deformation and low-temperature elasticity retention, making it difficult to directly adapt to the high-load service requirements of railway tracks. Patent CN114560991A discloses a polyurethane material made from polytetrahydrofuran diol, 2,4-toluene diisocyanate, 1,4-butanediol, and 3,3'-dichloro-4,4'-diaminodiphenylmethane in a specific ratio as raw materials, through prepolymer preparation and vulcanization steps. This material solves the problem of the mutual restriction between the dynamic performance and damping performance of polyurethane materials, and the prepolymer is stable in storage and production. However, the preparation process of this technology is relatively complex, involving multiple temperature control and vulcanization processes, resulting in high production costs. Furthermore, it does not take into account the actual service environment of railway track pads, and the optimization of the material's aging resistance and low-temperature adaptability is insufficient, making it difficult to meet the needs of large-scale production and complex working conditions of track pads.

[0005] Polyether polyols, as the core raw material of polyurethane materials, directly determine the final performance of polyurethane pads. Patents CN117887060A and CN120535721A both disclose amine polyether polyols. Amine ether polyols contain branches, increasing steric hindrance and improving damping effects. CN120535721A discloses that the synergistic effect of amine ether polyols with specific isocyanates also effectively improves damping, making it applicable to vibration damping and buffering. However, the stiffness performance required for heavy-haul railway track pads remains poor. Therefore, although existing polyurethane-related technologies have made some progress in damping performance, dynamic performance, or raw material modification, none have been specifically designed for the high load and complex working conditions of railway track pads (such as long-term wheel-rail impact, temperature and humidity fluctuations, and low-temperature environments). These technologies suffer from imbalances in damping performance and dynamic mechanical properties, insufficient aging resistance and low-temperature adaptability, complex manufacturing processes, and high production costs, failing to meet the high-performance requirements of high-speed and heavy-haul railways for buffer and vibration damping pads. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the above-mentioned defects of the prior art and provide a high-damping polyurethane pad and its preparation method. The prepared polyurethane pad has high damping, excellent dynamic performance, good aging resistance and low temperature adaptability, and the preparation process is simple and low cost.

[0007] The high-damping polyurethane pad of the present invention is mainly made of component A and component B, wherein component A mainly includes, by weight, 50-80 parts of amine ether polyol, 20-40 parts of polyether polyol, and 8-10 parts of ethylene glycol. Component B mainly comprises, by weight, 50-100 parts PTMG3000, 30-50 parts PTMG650, and 100-150 parts isocyanate; the mass ratio of PTMG3000 to PTMG650 in component B is 1:1 to 2.5:1. The preferred blend of PTMG3000 and PTMG650 comprises PTMG3000 (number average molecular weight 3000), a high molecular weight polyether polyol, and PTMG650 (number average molecular weight 650), a low molecular weight polyether polyol, with a mass ratio controlled between 1:1 and 2.5:1. PTMG3000 provides long-chain soft segments, giving the pad excellent elasticity and dynamic adaptability while reducing dynamic stiffness; PTMG650 provides short-chain hard segments, improving the static support stiffness and structural strength of the pad. The synergistic combination of these two components precisely controls the dynamic-to-static stiffness ratio of the pad to below 1.8, making it suitable for the high-load impact conditions of railway tracks and addressing the problem of dynamic-to-static stiffness imbalance in existing polyurethane pads. Based on the high-performance requirements of high-speed railways and heavy-haul railways for buffer and vibration damping pads, and in accordance with the requirement that the dynamic-to-static stiffness ratio be less than 2.0 in TB / T3395.1 and TB / T3395.2, and combined with actual usage conditions (lifespan, effect), this invention is designed to have a ratio below 1.8, which meets the standards of this invention.

[0008] The high molecular weight PTMG3000 and the low molecular weight PTMG650 are compounded to form a "soft segment-hard segment" interpenetrating network structure of polyurethane elastomer, which takes into account both the dynamic cushioning performance and static load-bearing performance of the pad, and avoids the insufficient structural strength caused by a single high molecular weight polyol or the insufficient elasticity caused by a single low molecular weight polyol.

[0009] The amine ether polyol is prepared by reacting N-dodecylethanolamine and propylene oxide at a molar ratio of 1:13-23 at 120-140°C. The resulting amine ether polyol has a functionality of 2 and a number-average molecular weight of 1000-1600.

[0010] Component A, by weight, also includes 0.1 to 0.3 parts silicone oil, 0.1 to 0.2 parts foaming agent, and 0.1 to 0.3 parts catalyst.

[0011] The N-dodecylethanolamine used in this invention has a tertiary amine structure, exhibiting autocatalytic activity, reducing the amount of external catalyst required, and simplifying the formulation system. It is a solid at room temperature with a high melting point; direct synthesis cannot meet the requirements of the prepolymer process. After polymerization with propylene oxide, it forms a long-chain liquid structure, satisfying the process operating conditions for prepolymer synthesis and ensuring raw material compatibility. The dodecyl long chain side chain of the amine ether polyol disrupts the regular arrangement of the polyurethane molecular chains, increasing the internal friction between molecular chain segments. Under external force, it converts mechanical energy into heat energy and dissipates it efficiently, significantly improving the damping performance of the pad and solving the problem of insufficient damping in traditional rubber and ordinary polyurethane pads. The amine ether polyol has a functionality of 2, forming a moderately cross-linked network with isocyanate, balancing elasticity and strength, avoiding excessive rigidity due to over-crosslinking or structural instability due to under-crosslinking.

[0012] The catalyst is one or more of bismuth catalysts, zinc catalysts, amine catalysts and tin catalysts, and is used in an amount of 0.1 to 0.3 parts. It works synergistically with the autocatalytic effect of amine ether polyol to accelerate the mixing reaction rate of components A and B, shorten the curing time, and improve the preparation efficiency. At the same time, the amount can be controlled to avoid the reaction from being too fast and running out of control, or the curing from being too slow and incomplete, thus ensuring the stability of product performance.

[0013] The foaming agent is water, used in amounts of 0.1 to 0.2 parts. It reacts with isocyanate to generate carbon dioxide gas, which works synergistically with silicone oil to achieve microporous structure regulation. The amount is precisely controlled to avoid over-foaming leading to low density and reduced strength of the pad, or under-foaming leading to poor damping performance, thus accurately matching the performance requirements of the pad.

[0014] The preferred silicone oil is DABCO DC6070, used in amounts of 0.1 to 0.3 parts. As a foam stabilizer, it can work synergistically with the polyol and foaming agent in component A to uniformly disperse the bubbles generated during the foaming process, prevent bubble aggregation or excessive size, and form a uniform microporous structure in the pad, further improving the damping performance and buffering effect. At the same time, it improves the processing fluidity of the material and enhances the preparation processability.

[0015] The isocyanate is diphenylmethane diisocyanate, preferably diphenylmethane diisocyanate (MDI-100). The MDI-100 used in this invention reacts efficiently with the hydroxyl groups in amine ether polyols and polyether polyols to form stable urethane bonds, constructing a continuous and uniform polyurethane crosslinking network. This improves the aging resistance, abrasion resistance, and hydrolysis resistance of the pad, making it suitable for the complex temperature and humidity environment of railway tracks. Simultaneously, MDI-100 has moderate reactivity, allowing for synergistic compatibility with various polyols and avoiding uneven network structure caused by excessively fast or slow reactions. The amount of MDI-100 is controlled at 100-150 parts, matching the hydroxyl content of the polyol to ensure complete reaction and no free isocyanate residue, guaranteeing product safety and performance stability. At the same time, it avoids excessive crosslinking due to excessive isocyanate, which could affect the elasticity of the pad.

[0016] The polyether polyol, with a hydroxyl value of 50-60 mgKOH / g and a functionality of 3 (preferably MN3050), is used in combination with an amine ether polyol. The amine ether polyol provides high damping properties. This polyether polyol, with its high molecular weight and 3 functions, constructs a uniform and resilient polyurethane soft segment structure, supplementing the elasticity and flexibility of the pad and mitigating the potential elasticity deficiency when used alone, thus achieving a balance between damping and elasticity. Furthermore, the selected hydroxyl value of 50-60 mgKOH / g is suitable for the reactivity of the amine ether polyol, enabling efficient synergistic reactions with ethylene glycol and isocyanate, accelerating the curing rate, improving preparation efficiency, and avoiding product performance defects caused by uneven local reactions.

[0017] This invention uses ethylene glycol as a small-molecule chain extender, working synergistically with polyether polyols and amine ether polyols. The small-molecule ethylene glycol can insert into the polyurethane molecular chain, reacting rapidly with isocyanate groups to moderately increase the crosslinking density, thereby enhancing the hardness and compression set resistance of the pad and preventing permanent deformation from long-term wheel-rail impact. Simultaneously, its dosage is controllable (8-10 parts), preventing a sudden increase in pad rigidity due to excessive crosslinking, thus ensuring effective cushioning and vibration reduction. The small-molecule ethylene glycol also works synergistically with the polyether polyol to regulate the reaction rate between components A and B, making the mixing reaction process more stable, reducing bubble formation, improving the pad's density and mechanical uniformity, and preventing internal defects caused by excessively rapid reactions.

[0018] The method for preparing the high-damping polyurethane pad of the present invention includes the following steps: (1) Preparation of Component A: Amine ether polyol, polyether polyol, ethylene glycol, silicone oil, foaming agent, and catalyst are mixed according to the weight proportions and stirred evenly to obtain Component A; the stirring speed is 100-300 r / min, the stirring time is 10-20 min, and the stirring temperature is 75-80℃. The stirring temperature in this step is controlled at 75-80℃ to match the reactivity of each raw material and avoid the decomposition of raw materials and premature volatilization of foaming agent due to excessive temperature, or uneven mixing of raw materials due to excessively low temperature; the stirring speed of 100-300 r / min and the stirring time of 10-20 min work together to ensure that each raw material is fully mixed evenly without local agglomeration, thus ensuring the performance stability of Component A.

[0019] (2) Preparation of component B: PTMG3000, PTMG650 and isocyanate are mixed in parts by weight, stirred, heated to 70-75°C and kept at that temperature, and then degassed to obtain component B; wherein, the holding time is preferably 2h and the degassed time is preferably 30min. The holding temperature of 70-75°C and the holding time of 2h in this step work together to ensure that PTMG3000, PTMG650 and isocyanate react fully to form a stable prepolymer and avoid product performance defects caused by incomplete reaction; degassed for 30min can remove air from component B, avoid the generation of bubbles during the mixing reaction, and improve the density and mechanical properties of the pad.

[0020] (3) Mix components A and B at a mass ratio of 1:1 to 1:1.4, allow to mature, and place at room temperature to obtain a high-damping polyurethane pad. The maturation temperature is 95 to 105°C, the maturation time is 40 to 44 hours, and the room temperature placement time is 6 to 8 days. This step uses a mass ratio of 1:1 to 1:1.4 to ensure complete reaction and no raw material residue; the maturation temperature of 95 to 105°C and the maturation time of 40 to 44 hours work together to further improve the polyurethane cross-linked network structure and enhance the mechanical properties, aging resistance, and dimensional stability of the pad; placing at room temperature for 6 to 8 days allows the pad to cool and solidify slowly, avoiding internal stress caused by rapid cooling and ensuring the long-term service stability of the product.

[0021] Compared with the prior art, the beneficial effects of the present invention are: (1) This invention combines customized amine ether polyols with specific polyether polyols, and with the synergistic effect of small molecule chain extender ethylene glycol, which not only solves the defects of insufficient damping, easy aging, and low-temperature elastic decay of traditional rubber pads, but also overcomes the problem of unbalanced damping and dynamic mechanical properties of existing polyurethane technology, achieving a synergistic improvement of high damping performance and excellent mechanical properties. At the same time, it is suitable for high load and complex temperature and humidity conditions of railway tracks, and significantly extends the service life of the pads.

[0022] (2) The present invention optimizes the compounding ratio of PTMG3000 and PTMG650 in component B, constructs an interpenetrating network structure of "soft segment-hard segment", and accurately controls the dynamic and static stiffness ratio of the pad to below 1.8. This solves the problem of insufficient stiffness of polyurethane materials in existing related technologies and their inability to meet the requirements of heavy-load railway tracks. It takes into account both static load-bearing capacity and dynamic buffering and vibration reduction effect, ensuring driving safety and comfort.

[0023] (3) The present invention simplifies the preparation process, eliminates the need for a complex vulcanization process, optimizes the reaction conditions through the synergistic effect of each raw material, and the raw materials are readily available and the amount used is controllable, which reduces production costs and improves production efficiency. At the same time, the self-catalytic effect of amine ether polyols simplifies the formulation system, reduces the amount of catalyst used, ensures stable product performance and enables industrial-scale production, and solves the problems of complex and high cost of existing polyurethane pad preparation processes. Detailed Implementation

[0024] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments.

[0025] Unless otherwise specified, all raw materials used in the examples were commercially available. The parameters of the raw materials used are as follows: Amine ether polyol A was prepared by reacting N-dodecylethanolamine and propylene oxide at a molar ratio of 1:13 at a reaction temperature of 120℃. The resulting product had a functionality of 2 and a number-average molecular weight of 1000. The specific steps were as follows: 273.5g of N-dodecylethanolamine was first added to a high-pressure reactor. The reactor was then purged with nitrogen multiple times to remove air. The temperature was raised to 110℃ and dehydrated under negative pressure for 30 minutes. After removing trace amounts of water from the system, the temperature was further raised to 120℃ and held constant. Propylene oxide (total 754g) was added in three batches at a controlled temperature, with the pressure inside the reactor controlled at 0.20–0.4 MPa. After the propylene oxide was fed, the reactor was kept at 120°C for 2.0 h until the pressure stabilized and no longer dropped, ensuring complete polymerization of the monomer. After the reaction was completed, the temperature was lowered to 80–90°C, and residual propylene oxide and low-boiling substances were removed under high vacuum for 40–60 min. The product was then cooled and discharged to obtain amine ether polyol A, which had a number average molecular weight of 1000 and a functionality of 2.

[0026] Amine ether polyol B was prepared by reacting N-dodecylethanolamine and propylene oxide at a molar ratio of 1:20 at a reaction temperature of 130℃. The resulting product had a functionality of 2 and a number-average molecular weight of 1400. The specific steps were as follows: In a high-pressure reactor, 273.5g of N-dodecylethanolamine was first added. The air inside the reactor was removed by multiple purgings with nitrogen. The temperature was raised to 110℃ and dehydrated under negative pressure for 30 minutes. After removing trace amounts of water from the system, the temperature was raised to 130℃ and kept constant. At this temperature, propylene oxide (total 1160g) was added in four batches. The pressure inside the reactor was controlled at 0.20-0.4MPa. After the propylene oxide was fed, the reactor was kept at 130℃ for 2.0h until the pressure in the reactor stabilized and no longer dropped, ensuring complete polymerization of the monomer. After the reaction is completed, the temperature is lowered to 80-90℃, and residual propylene oxide and low-boiling substances are removed under high vacuum for 40-60 minutes. The product is then cooled and discharged to obtain amine ether polyol B, which has a number-average molecular weight of 1400 and a functionality of 2.

[0027] Amine ether polyol C: N-dodecylethanolamine and propylene oxide were reacted at a molar ratio of 1:23 at a reaction temperature of 140℃. The resulting product had a functionality of 2 and a number-average molecular weight of 1600. The specific steps were as follows: In a high-pressure reactor, 273.5g of N-dodecylethanolamine was first added. The air inside the reactor was removed by multiple purgings with nitrogen. The temperature was raised to 110℃ and dehydrated under negative pressure for 30 min. After removing trace amounts of water from the system, the temperature was raised to 140℃ and kept constant. At this temperature, propylene oxide (totaling 1334g) was added in four batches, with the pressure inside the reactor controlled at 0.20-0.4MPa during the dropwise addition process. After the propylene oxide was completely fed, the reactor was kept at 140℃ for 2.0h until the pressure in the reactor stabilized and no longer decreased, ensuring complete polymerization of the monomer. After the reaction is completed, the temperature is lowered to 80-90℃, and residual propylene oxide and low-boiling substances are removed under high vacuum for 40-60 minutes. The product is then cooled and discharged to obtain amine ether polyol C, which has a number-average molecular weight of 1400 and a functionality of 2.

[0028] MN3050: Polyether polyol, hydroxyl value 56mgKOH / g, functionality 3, Shandong Lanxing Dongda Co., Ltd.; PTMG3000: Polytetrahydrofuran polyol, hydroxyl value 37mgKOH / g, functionality 2, Hyosung Chemical (Jiaxing) Co., Ltd. PTMG650: Polytetrahydrofuran polyol, hydroxyl value 173 mgKOH / g, functionality 2, Hyosung Chemical (Jiaxing) Co., Ltd. Ethylene glycol: hydroxyl value 1807 mgKOH / g, functionality 2, Hengli Petrochemical Co., Ltd.; Silicone oil: DABCO DC6070, Dow Chemical Company; Catalyst: DMCHA (N,N-dimethylcyclohexylamine), Jinan Huifengda Chemical Co., Ltd.; MDI-100: Diphenylmethane diisocyanate, Yantai Wanhua Chemical Group Co., Ltd.; Foaming agent: water.

[0029] Raw materials used for comparison: N-n-Butyldiethanolamine: Functionality 2, Qingdao Zhongke Fengyuan New Materials Co., Ltd.; DL3000D: Polyether polyol, hydroxyl value 36mgKOH / g, functionality 2, Shandong Lanxing Dongda Co., Ltd. 1,4-Butanediol: Hydroxyl value 1122 mgKOH / g, functionality 2, Xinjiang Xinyue Energy Chemical Co., Ltd.

[0030] Example 1 The method for preparing the high-damping polyurethane pad of the present invention includes the following steps: Preparation steps of component A: By weight, 60 parts of amine ether polyol B, 30 parts of MN3050, 10 parts of ethylene glycol, 0.1 parts of silicone oil, 0.1 parts of foaming agent (water), and 0.2 parts of catalyst (DMCHA) are mixed and stirred at 80℃ and 200r / min for 15min until homogeneous to obtain component A.

[0031] Preparation steps of component B: By weight, add 50 parts of PTMG3000, 50 parts of PTMG650 and 130 parts of MDI-100 to the reactor, turn on the stirrer, heat to 72℃ and keep warm for 2 hours, degas for 30 minutes to obtain component B.

[0032] Product preparation: When using, components A and B are mixed and reacted at a mass ratio of 100:127, cured at 100℃ for 42 hours, and placed at room temperature for 7 days to achieve the performance required for use, thus obtaining a high-damping polyurethane pad.

[0033] Example 2 The method for preparing the high-damping polyurethane pad of the present invention includes the following steps: Preparation steps of component A: By weight, 60 parts of amine ether polyol C, 30 parts of MN3050, 10 parts of ethylene glycol, 0.3 parts of silicone oil, 0.15 parts of foaming agent (water) and 0.3 parts of catalyst (DMCHA) are mixed and stirred at 80℃ and 300r / min for 10min until homogeneous to obtain component A.

[0034] Preparation steps of component B: By weight, add 70 parts of PTMG3000, 30 parts of PTMG650 and 150 parts of MDI-100 to the reactor, turn on the stirrer, heat to 75℃ and keep warm for 2 hours, degas for 30 minutes to obtain component B.

[0035] Product preparation: When using, components A and B are mixed and reacted at a mass ratio of 100:110, aged at 100℃ for 42 hours, and placed at room temperature for 7 days to achieve the performance required for use, thus obtaining a high-damping polyurethane pad.

[0036] Example 3 The method for preparing the high-damping polyurethane pad of the present invention includes the following steps: Preparation steps of component A: By weight, 80 parts of amine ether polyol A, 20 parts of MN3050, 8 parts of ethylene glycol, 0.3 parts of silicone oil, 0.15 parts of foaming agent (water), and 0.2 parts of catalyst (DMCHA) are mixed and stirred at 75℃ and 180r / min for 18min until homogeneous to obtain component A.

[0037] Preparation steps of component B: By weight, 70 parts of PTMG3000, 30 parts of PTMG650 and 118 parts of MDI-100 were added to the reactor, stirred, heated to 73°C and kept at that temperature for 2 hours, and degassed for 30 minutes to obtain component B.

[0038] Product preparation: When using, components A and B are mixed and reacted at a mass ratio of 100:119, cured at 100℃ for 42 hours, and placed at room temperature for 7 days to achieve the performance required for use, thus obtaining a high-damping polyurethane pad.

[0039] Example 4 The method for preparing the high-damping polyurethane pad of the present invention includes the following steps: Preparation steps of component A: By weight, mix 50 parts of amine ether polyol C, 40 parts of MN3050, 10 parts of ethylene glycol, 0.3 parts of silicone oil, 0.15 parts of foaming agent (water), and 0.1 parts of catalyst (DMCHA), and stir for 20 minutes at 75℃ and 100r / min until homogeneous to obtain component A.

[0040] Preparation steps of component B: By weight, 70 parts of PTMG3000, 30 parts of PTMG650 and 118 parts of MDI-100 were added to the reactor, stirred, heated to 74℃ and kept at that temperature for 2 hours, and degassed for 30 minutes to obtain component B.

[0041] Product preparation: When using, components A and B are mixed and reacted at a mass ratio of 100:126, aged at 100℃ for 42 hours, and placed at room temperature for 7 days to achieve the performance required for use, thus obtaining a high-damping polyurethane pad.

[0042] Example 5 The method for preparing the high-damping polyurethane pad of the present invention includes the following steps: Preparation steps of component A: By weight, 70 parts of amine ether polyol B, 35 parts of MN3050, 9 parts of ethylene glycol, 0.2 parts of silicone oil, 0.15 parts of foaming agent (water), and 0.2 parts of catalyst (DMCHA) are mixed and stirred at 75℃ and 200r / min for 15min until homogeneous to obtain component A.

[0043] Preparation steps of component B: By weight, add 100 parts of PTMG3000, 40 parts of PTMG650 and 125 parts of MDI-100 to the reactor, turn on the stirrer, heat to 72℃ and keep warm for 2 hours, degas for 30 minutes to obtain component B.

[0044] Product preparation: When using, components A and B are mixed and reacted at a mass ratio of 100:127, aged at 105℃ for 40 hours, and placed at room temperature for 6 days to achieve the performance required for use, thus obtaining a high-damping polyurethane pad.

[0045] Example 6 The method for preparing the high-damping polyurethane pad of the present invention includes the following steps: Preparation steps of component A: By weight, 55 parts of amine ether polyol B, 32 parts of MN3050, 8.5 parts of ethylene glycol, 0.15 parts of silicone oil, 0.12 parts of foaming agent (water), and 0.15 parts of catalyst (DMCHA) are mixed and stirred at 80℃ and 220r / min for 14min until homogeneous to obtain component A.

[0046] Preparation steps of component B: By weight, 60 parts of PTMG3000, 45 parts of PTMG650 and 140 parts of MDI-100 were added to the reactor, stirred, heated to 71℃ and kept at that temperature for 2 hours, and degassed for 30 minutes to obtain component B.

[0047] Product preparation: When using, components A and B are mixed and reacted at a mass ratio of 100:113, cured at 95℃ for 44 hours, and placed at room temperature for 8 days to achieve the performance required for use, thus obtaining a high-damping polyurethane pad.

[0048] Comparative Example 1 The difference between this comparative example and Example 1 is that the amine ether polyol in component A is prepared by reacting N-n-butyldiethanolamine and propylene oxide at a molar ratio of 1:21.5, and the product has a functionality of 2 and a molecular weight of 1400. Otherwise, it is the same as Example 1.

[0049] Comparative Example 2 The difference between this comparative example and Example 1 is that PTMG3000 in component B is replaced with an equal mass of DL3000D; otherwise, they are the same as in Example 1.

[0050] Comparative Example 3 The difference between this comparative example and Example 1 is that the ethylene glycol in component A is replaced with an equal weight of 1,4-butanediol, and components A and B are mixed and reacted in a 100:100 ratio. Otherwise, it is the same as Example 1.

[0051] Comparative Example 4 The difference between this comparative example and Example 1 is that PTMG3000 in component B is 40 parts and PTMG650 is 60 parts; otherwise, they are the same as in Example 1.

[0052] Comparative Example 5 The difference between this comparative example and Example 1 is that no amine ether polyol was added to component A, and it was replaced with an equal mass of MN3050. Otherwise, it is the same as Example 1.

[0053] Comparative Example 6 The difference between this comparative example and Example 1 is that PTMG650 was not added to component B, and only 100 parts of PTMG3000 were used. The preparation of component A was the same as in Example 1. Otherwise, it was the same as in Example 1.

[0054] Performance testing I. Core Performance Parameters 1. Damping performance: Loss factor (tanδ) at 60Hz, tested according to GB / T19466.2-2025 "Differential scanning calorimetry (DSC) for plastics - Part 2: Determination of glass transition temperature and glass transition step height"; loss factor at three temperatures: -40℃ (low temperature condition), 25℃ (normal temperature condition), and 60℃ (high temperature condition).

[0055] 2. Stiffness performance: The ratio of dynamic stiffness to static stiffness and static stiffness are tested in accordance with TB / T3395.1-2015 "Railway Fasteners Part 1: Elastic Bar Fasteners".

[0056] 3. Mechanical properties: tensile strength (unit: MPa) and elongation at break (unit: %), tested according to GB / T10654-2001 "Determination of tensile properties of thermoplastics".

[0057] II. Aging Resistance and Long-Term Service Performance Parameters 1. Compression set (unit: %): Tested according to GB / T7759-2019 "Determination of compression set of vulcanized rubber or thermoplastic rubber", with test conditions of 70℃×22h (simulating long-term service high temperature conditions).

[0058] 2. Aging resistance: Tensile strength retention rate (unit: %) and elongation at break retention rate (unit: %) after hot air aging are tested according to GB / T3512-2014 "Accelerated aging and heat resistance test of vulcanized rubber or thermoplastic rubber in hot air", with test conditions of 100℃×72h.

[0059] 3. Low-temperature elastic properties: Low-temperature brittleness temperature (unit: °C), tested according to GB / T 15256-2014 "Determination of Low-Temperature Brittleness of Vulcanized Rubber (Multiple Sample Method)". Specific performance indicators are shown in Table 1 below. Table 1 Performance test results of Examples 1-6 and Comparative Examples 1-6

[0060] As can be seen from the data in Table 1, the amine ether polyols used in Examples 1-6 have a loss factor of less than 0.41 at 25°C, a dynamic-to-static stiffness ratio of less than 1.8, excellent mechanical properties, a compression set rate of about 3%, a low-temperature brittleness temperature of no more than -40°C, and a tensile strength retention rate of more than 87% after hot air aging.

[0061] Compared with Example 1, Comparative Example 1 uses N-n-butyldiethanolamine and propylene oxide in a molar ratio of 1:21.5 to prepare a polyol with a molecular weight of 1400 to replace the amine ether polyol B. Since the side chain has only four alkyl groups, the degree of damage to the regular arrangement of the molecular structure is low, and it cannot effectively reduce the friction between molecular chain segments. The damping effect is poor and it is difficult to meet the requirements.

[0062] Compared with Example 1, Comparative Example 2 uses DL3000D instead of PTMG3000. Ordinary polyether polyol has a better damping effect at room temperature, but due to the existence of side chain friction, the dynamic-to-static stiffness ratio is higher and it is difficult to meet the requirements.

[0063] Compared with Example 1, Comparative Example 3 uses 1,4-butanediol instead of ethylene glycol. Since 1,4-butanediol has good crystallization and clear phase separation, its damping effect is worse and it is difficult to meet the requirements.

[0064] Compared with Example 1, the mass ratio of PTMG3000 to PTMG650 in Comparative Example 4 is 0.67:1, which exceeds the range of 1:1 to 2.5:1 defined by the present invention. Due to the increase in the amount of PTMG650, the proportion of hard segments will also increase. While the damping effect is improved, the dynamic-static stiffness ratio will also increase, which is difficult to meet the requirements.

[0065] Compared with Example 1, Comparative Example 5 did not use amine ether polyol, but instead used the same mass of MN3050. The dynamic-to-static stiffness ratio was higher than 1.8, which was due to excessive crosslinking, making it difficult to meet the requirements.

[0066] Compared with Example 1, Comparative Example 6 did not use PTMG650, but only PTMG3000. The dynamic-to-static stiffness ratio was reduced, but the damping effect was lower than that of the high-low polyol blend, which was difficult to meet the requirements.

Claims

1. A high-damping polyurethane pad, characterized in that: It includes component A and component B, with a mass ratio of 1:1 to 1:1.

4. Component A includes, by weight, 50 to 80 parts of amine ether polyol, 20 to 40 parts of polyether polyol, 8 to 10 parts of ethylene glycol, 0.1 to 0.3 parts of silicone oil, 0.1 to 0.2 parts of foaming agent, and 0.1 to 0.3 parts of catalyst. Component B comprises, by weight, 50-100 parts PTMG3000, 30-50 parts PTMG650, and 100-150 parts isocyanate; wherein the mass ratio of PTMG3000 to PTMG650 in Component B is 1:1 to 2.5:

1. The amine ether polyol is prepared by reacting N-dodecylethanolamine and propylene oxide at a molar ratio of 1:13-23 at 120-140°C. The resulting amine ether polyol has a functionality of 2 and a number-average molecular weight of 1000-1600. Polyether polyols with a hydroxyl value of 50-60 mgKOH / g and a functionality of 3.

2. The high-damping polyurethane pad according to claim 1, characterized in that: The catalyst is one or more of the following: bismuth catalyst, zinc catalyst, amine catalyst, and tin catalyst.

3. The high-damping polyurethane pad according to claim 2, characterized in that: The foaming agent is water.

4. The high-damping polyurethane pad according to claim 1, characterized in that: The silicone oil is DABCO DC6070.

5. The high-damping polyurethane pad according to claim 1, characterized in that: The isocyanate is diphenylmethane diisocyanate.

6. A method for preparing a high-damping polyurethane pad according to any one of claims 1-5, characterized in that: Includes the following steps: (1) Preparation of component A: Mix amine ether polyol, polyether polyol, ethylene glycol, silicone oil, foaming agent and catalyst according to the weight parts, stir evenly to obtain component A; (2) Preparation of component B: PTMG3000, PTMG650 and isocyanate are mixed in parts by weight, stirred, heated to 70-75℃ and kept at that temperature, and then degassed to obtain component B; (3) Mix and react components A and B, mature them, and place them at room temperature to obtain a high-damping polyurethane pad.

7. The method for preparing the high-damping polyurethane pad according to claim 6, characterized in that: In step (3), the curing temperature is 95-105℃, the curing time is 40-44h, and the room temperature is left for 6-8 days.

8. The method for preparing the high-damping polyurethane pad according to claim 6, characterized in that: In step (1), the stirring speed is 100-300 r / min, the stirring time is 10-20 min, and the stirring temperature is 75-80℃.

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