Polyurethane elastomers for steel rail energy dissipaters and process for their preparation

Abstract

The present application relates to the technical field of elastomer preparation, in particular to a polyurethane elastomer for a rail energy dissipation member and a preparation process thereof, which comprises the following components: modified stabilizer 10-15 parts by weight, L-lysine diisocyanate 55-65 parts by weight, polyadipate polyol 95-110 parts by weight, dibutyltin dilaurate catalyst 1.5-2.5 parts by weight, 1,4-butanediol chain extender 5-10 parts by weight, silica filler 25-30 parts by weight, 2,6-di-tert-butyl-p-cresol antioxidant 0.5-1.0 parts by weight, ethylenediaminetetramethylene phosphonic acid 1-10 parts by weight, and KH-550 silane coupling agent 1-3 parts by weight; wherein the modified stabilizer is prepared from lauryl alcohol and (R)-2-amino-3-(phenyl selenyl) propionic acid at a mass ratio of 1:0.5-1.1, and the polyurethane elastomer prepared by using the modified stabilizer can improve the flexibility, hydrophobicity and oxidation resistance of the material, thereby improving the mechanical properties, chemical stability and aging resistance of the polyurethane elastomer, prolonging the service life and reducing the maintenance cost.

Description

Technical Field

[0001] This invention relates to the field of elastomer preparation technology, and more specifically, to polyurethane elastomers for energy-consuming components of rails and their preparation process. Background Technology

[0002] Polyurethane elastomers, also known as polyurethane elastomers, are rich in urethane groups in their main chain. They are produced through stepwise addition polymerization of oligomeric polyols such as polyesters, polyethers, or polyolefins with polyisocyanates and chain extenders such as glycols or diamines. Their molecular structure consists of alternating soft and hard segments. The soft segments impart high elasticity, while the hard segments provide strength and rigidity. This structure gives polyurethane elastomers both the flexibility and elasticity of rubber and the strength and wear resistance of plastics. In rail energy-consuming components, polyurethane elastomers are mainly used to manufacture shock-absorbing pads, damping materials, and other key components. Key components, which absorb and disperse the vibration and impact energy generated during train operation, significantly reduce vibration transmission between the rail and the roadbed, reduce noise pollution, and protect the rail and track structure from long-term fatigue damage. Therefore, they have significant advantages in the application of rail energy-consuming components. However, the performance of existing polyurethane elastomers will decline significantly due to aging under long-term sun exposure, and they are also susceptible to corrosion by solvents such as water, alcohol, and acid, resulting in swelling and degradation. In view of this, we propose a polyurethane elastomer for rail energy-consuming components and its preparation process. Summary of the Invention

[0003] The purpose of this invention is to provide a polyurethane elastomer for energy-consuming components of rails and its preparation process, so as to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides a polyurethane elastomer for energy-consuming components of steel rails, comprising the following components: 10-15 parts by weight of modified stabilizer, 55-65 parts by weight of L-lysine diisocyanate, 95-110 parts by weight of polyadipate polyol, 1.5-2.5 parts by weight of dibutyltin dilaurate catalyst, 5-10 parts by weight of 1,4-butanediol chain extender, 25-30 parts by weight of silica filler, 0.5-1.0 parts by weight of 2,6-di-tert-butyl-p-cresol antioxidant, 0.3-0.6 parts by weight of Chimassorb 2020 hindered amine light stabilizer, 1-10 parts by weight of ethylenediaminetetramethylenephosphonic acid, and 1-3 parts by weight of KH-550 silane coupling agent;

[0005] The modified stabilizer is prepared by lauryl alcohol and (R)-2-amino-3-(phenylseleno)propionic acid in a mass ratio of 1:0.5 to 1.1.

[0006] The silica filler is fumed silica with an average particle size of 10-50 nm and a specific surface area of ​​150-300 m² / g. The surface is pretreated with KH-550 silane coupling agent.

[0007] Preferably, the modified stabilizer is prepared by the following method:

[0008] Lauryl alcohol was dissolved in dichloromethane to prepare a lauryl alcohol solution. (R)-2-amino-3-(phenylseleno)propionic acid was dissolved separately in dichloromethane to obtain a (R)-2-amino-3-(phenylseleno)propionic acid solution. Dicyclohexylcarbodiimide was added to the (R)-2-amino-3-(phenylseleno)propionic acid solution, and the mixture was stirred in an ice bath for 25-30 min. Then, 4-dimethylaminopyridine was added, and the mixture was stirred for another 10-15 min. Lauryl alcohol solution was added dropwise, and the temperature was raised to 40-45℃. The reaction was carried out for 4-6 h. The activation degree of the carboxylic acid was monitored by thin-layer chromatography to confirm the carboxylic acid spots. When the ester product spots began to appear, the mixture was filtered and washed with 3-5% (v / v) dilute hydrochloric acid. The mixture was dried over 5-10% (w / v) anhydrous sodium sulfate, and the solvent was removed by rotary evaporation. The mixture was then purified by silica gel column chromatography to obtain the modified stabilizer.

[0009] First, the carboxyl group of (R)-2-amino-3-(phenylseleno)propionic acid is activated by dicyclohexylcarbodiimide to generate an active intermediate. 4-Dimethylaminopyridine acts as a nucleophilic catalyst to accelerate esterification. Next, the activated carboxylic acid reacts with lauryl alcohol to form an ester bond. Therefore, the carboxyl group on (R)-2-amino-3-(phenylseleno)propionic acid is linked to the hydroxyl group on lauryl alcohol, thereby introducing the fatty alcohol group of lauryl alcohol onto (R)-2-amino-3-(phenylseleno)propionic acid.

[0010] The modified (R)-2-amino-3-(phenylseleno)propionic acid has an additional amino group that can react with the isocyanate group on L-lysine diisocyanate. The amino group acts as a nucleophile, attacking the isocyanate group to form a carbamate bond, which then attaches to the L-lysine diisocyanate. This extends the branch length of the polyurethane elastomer, improving the material's flexibility. The longer branches increase the distance between polymer chains, reducing the close packing of molecules, thus making the internal chain segments easier to move, maintaining the material's softness and flexibility. Furthermore, the long branches can also act as a "lubricant" between molecules, reducing friction between molecular chains and making the material... When subjected to stress, it can better absorb energy and dissipate it through plastic deformation rather than brittle fracture. However, excessively long branches can easily lead to a decrease in the wear resistance of polyurethane. The presence of phenyl groups on (R)-2-amino-3-(phenylseleno)propionic acid can increase the rigidity of the polymer chain, thereby mitigating the disadvantage of excessive flexibility of the fatty acid groups on lauryl alcohol in polyurethane elastomers. At the same time, the fatty acid groups on lauryl alcohol are hydrophobic, which can improve the hydrophobicity of polyurethane elastomers, effectively reducing water erosion and making it less prone to water absorption and swelling or performance degradation due to moisture. In railway applications, this means a longer material life, lower maintenance frequency, and effective cost reduction.

[0011] The presence of selenium in (R)-2-amino-3-(phenylseleno)propionic acid, due to the electronic properties of selenium, can act as an antioxidant, helping to scavenge free radicals and thus slowing down the aging process of materials. Selenium compounds also exhibit certain antibacterial properties, affecting the growth of microorganisms. Therefore, introducing selenium into polyurethane materials can endow the materials with certain antibacterial functions, thereby improving the durability and service life of polyurethane elastomers.

[0012] The added ethylenediaminetetramethylenephosphonic acid can react with selenium to form a stable complex, which can be used to reduce the environmental impact of unreacted or exposed selenium.

[0013] Preferably, the lauryl alcohol solution has a mass concentration of 7-9 mg / mL.

[0014] Preferably, the mass concentration of the (R)-2-amino-3-(phenylseleno)propionic acid solution is 14-16 mg / mL.

[0015] Preferably, the molar ratio of the dicyclohexylcarbodiimide to (R)-2-amino-3-(phenylseleno)propionic acid is 1.1 to 1.3:1.

[0016] Preferably, the molar ratio of 4-dimethylaminopyridine to (R)-2-amino-3-(phenylseleno)propionic acid is 0.1 to 0.15:1.

[0017] On the other hand, the present invention provides a process for preparing a polyurethane elastomer for rail energy-consuming components, comprising the following steps:

[0018] L-lysine diisocyanate, polyadipate polyol, and modified stabilizer are mixed and reacted in a water bath at 60-80℃ to obtain a polyurethane prepolymer. The mixture is continuously stirred with a magnetic stirrer at a speed of 200-400 rpm / min for 2-3 hours. Dibutyltin dilaurate catalyst, 1,4-butanediol chain extender, silica filler, 2,6-di-tert-butyl-p-cresol antioxidant, Chimassorb 2020 hindered amine light stabilizer, ethylenediaminetetramethylenephosphonic acid, and KH-550 silane coupling agent are mixed and dehydrated under vacuum at 100-120℃. The mixture and polyurethane prepolymer are then mixed, heated, and stirred at 40-50℃ to obtain a compound. The compound is then injected into a mold and molded at 70-75℃. After demolding, curing, grinding, and cleaning, a polyurethane elastomer for use in rail energy-consuming components is obtained.

[0019] Preferably, the polyadipate polyol is polybutylene adipate with a functionality of 2 and a number-average molecular weight of 1800-2200.

[0020] Preferably, the mixture after vacuum dehydration has a moisture content of less than 0.05%.

[0021] Preferably, the curing temperature is 80-85℃ and the curing time is 24-32h.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] In the polyurethane elastomer used for energy-consuming components of steel rails and its preparation process, a modified stabilizer is used to prepare the polyurethane elastomer. Hydrophobic fatty acid groups on lauryl alcohol are introduced to give the material better hydrophobicity and moisture resistance, avoiding the performance degradation of polyurethane elastomer caused by moisture erosion. The fatty acid groups on lauryl alcohol are used to improve the flexibility of the polyurethane elastomer. The addition of (R)-2-amino-3-(phenylseleno)propionic acid can, on the one hand, use the rigidity of phenyl to alleviate the problem of excessive flexibility of polyurethane elastomer caused by branched fatty acid groups. On the other hand, the electronic properties of selenium help to scavenge free radicals, thereby slowing down the aging process of the material, greatly improving the service life and durability of the material, and reducing maintenance costs. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] The polyurethane elastomer for energy-consuming components of steel rails of the present invention comprises the following components: 10-15 parts by weight of modified stabilizer, 55-65 parts by weight of L-lysine diisocyanate, 95-110 parts by weight of polyadipate polyol, 1.5-2.5 parts by weight of dibutyltin dilaurate catalyst, 5-10 parts by weight of 1,4-butanediol chain extender, 25-30 parts by weight of silica filler, 0.5-1.0 parts by weight of 2,6-di-tert-butyl-p-cresol antioxidant, 0.3-0.6 parts by weight of Chimassorb 2020 hindered amine light stabilizer, 1-10 parts by weight of ethylenediaminetetramethylenephosphonic acid, and 1-3 parts by weight of KH-550 silane coupling agent;

[0026] The modified stabilizer is prepared by lauryl alcohol and (R)-2-amino-3-(phenylseleno)propionic acid in a mass ratio of 0.5 to 1.1.

[0027] Example 1: A polyurethane elastomer for energy-consuming components of steel rails and its preparation process, comprising the following steps:

[0028] Preparation of components: 13 parts by weight of modified stabilizer, 55 parts by weight of L-lysine diisocyanate, 95 parts by weight of polyadipate polyol, 1.5 parts by weight of dibutyltin dilaurate catalyst, 5 parts by weight of 1,4-butanediol chain extender, 25 parts by weight of silica filler, 0.5 parts by weight of 2,6-di-tert-butyl-p-cresol antioxidant, and Chimassorb. The mixture comprises 0.3 parts by weight of hindered amine light stabilizer 2020, 1 part by weight of ethylenediaminetetramethylenephosphonic acid, and 1 part by weight of KH-550 silane coupling agent; wherein the modified stabilizer is prepared by lauryl alcohol and (R)-2-amino-3-(phenylseleno)propionic acid in a mass ratio of 1:0.5; the mass concentration of the lauryl alcohol solution is 7 mg / mL, and the mass concentration of the (R)-2-amino-3-(phenylseleno)propionic acid solution is 14 mg / mL; the molar ratio of dicyclohexylcarbodiimide to (R)-2-amino-3-(phenylseleno)propionic acid is 1.2:1; and the molar ratio of 4-dimethylaminopyridine to (R)-2-amino-3-(phenylseleno)propionic acid is 0.12:1.

[0029] Lauryl alcohol was dissolved in dichloromethane to prepare a lauryl alcohol solution. (R)-2-amino-3-(phenylseleno)propionic acid was dissolved separately in dichloromethane to obtain a (R)-2-amino-3-(phenylseleno)propionic acid solution. Dicyclohexylcarbodiimide was added to the (R)-2-amino-3-(phenylseleno)propionic acid solution, and the mixture was stirred in an ice bath for 30 min. Then, 4-dimethylaminopyridine was added, and the mixture was stirred for another 15 min. Lauryl alcohol solution was added dropwise, and the mixture was heated to 40 °C and reacted for 4 h. The activation degree of the carboxylic acid was monitored by thin-layer chromatography to confirm the carboxylic acid spots. When the ester product spots began to appear, the mixture was filtered and washed with 5% (v / v) dilute hydrochloric acid, dried over 10% (w / v) anhydrous sodium sulfate, and the solvent was removed by rotary evaporation. The mixture was then purified by silica gel column chromatography to obtain the modified stabilizer.

[0030] L-lysine diisocyanate, polyadipate polyol, and modified stabilizer were mixed and reacted in a water bath at 60°C to obtain a polyurethane prepolymer. The mixture was continuously stirred with a magnetic stirrer at a speed of 400 rpm / min for 3 hours. Dibutyltin dilaurate catalyst, 1,4-butanediol chain extender, silica filler, 2,6-di-tert-butyl-p-cresol antioxidant, Chimassorb 2020 hindered amine light stabilizer, and KH-550 silane coupling agent were mixed and vacuum dehydrated at 120°C to a moisture content of less than 0.05%. The mixture, ethylenediaminetetramethylenephosphonic acid, and polyurethane prepolymer were mixed, heated, and stirred at 40°C to obtain a mixture. The mixture was then injected into a mold at 70°C for molding, demolded, and cured at 80°C for 24 hours. After grinding and cleaning, a polyurethane elastomer for use in rail energy-consuming components was obtained.

[0031] Example 2: Polyurethane elastomer for energy-consuming components of rails and its preparation process, including the following steps:

[0032] Preparation of components: 13 parts by weight of modified stabilizer, 55 parts by weight of L-lysine diisocyanate, 95 parts by weight of polyadipate polyol, 1.5 parts by weight of dibutyltin dilaurate catalyst, 5 parts by weight of 1,4-butanediol chain extender, 25 parts by weight of silica filler, 0.5 parts by weight of 2,6-di-tert-butyl-p-cresol antioxidant, and Chimassorb. The mixture comprises 0.3 parts by weight of hindered amine light stabilizer 2020, 1 part by weight of ethylenediaminetetramethylenephosphonic acid, and 1 part by weight of KH-550 silane coupling agent; wherein the modified stabilizer is prepared by lauric acid and (R)-2-amino-3-(phenylseleno)propionic acid in a mass ratio of 1:0.8; the mass concentration of lauryl alcohol solution is 7 mg / mL, and the mass concentration of (R)-2-amino-3-(phenylseleno)propionic acid solution is 14 mg / mL; the molar ratio of dicyclohexylcarbodiimide to (R)-2-amino-3-(phenylseleno)propionic acid is 1.2:1; and the molar ratio of 4-dimethylaminopyridine to (R)-2-amino-3-(phenylseleno)propionic acid is 0.12:1.

[0033] Lauryl alcohol was dissolved in dichloromethane to prepare a lauryl alcohol solution. (R)-2-amino-3-(phenylseleno)propionic acid was dissolved separately in dichloromethane to obtain a (R)-2-amino-3-(phenylseleno)propionic acid solution. Dicyclohexylcarbodiimide was added to the (R)-2-amino-3-(phenylseleno)propionic acid solution, and the mixture was stirred in an ice bath for 30 min. Then, 4-dimethylaminopyridine was added, and the mixture was stirred for another 15 min. Lauryl alcohol solution was added dropwise, and the mixture was heated to 40 °C and reacted for 4 h. The activation degree of the carboxylic acid was monitored by thin-layer chromatography to confirm the carboxylic acid spots. When the ester product spots began to appear, the mixture was filtered and washed with 5% (v / v) dilute hydrochloric acid, dried over 10% (w / v) anhydrous sodium sulfate, and the solvent was removed by rotary evaporation. The mixture was then purified by silica gel column chromatography to obtain the modified stabilizer.

[0034] L-lysine diisocyanate, polyadipate polyol, and modified stabilizer were mixed and reacted in a water bath at 60°C to obtain a polyurethane prepolymer. The mixture was continuously stirred with a magnetic stirrer at a speed of 400 rpm / min for 3 hours. Dibutyltin dilaurate catalyst, 1,4-butanediol chain extender, silica filler, 2,6-di-tert-butyl-p-cresol antioxidant, Chimassorb 2020 hindered amine light stabilizer, and KH-550 silane coupling agent were mixed and vacuum dehydrated at 120°C to a moisture content of less than 0.05%. The mixture, ethylenediaminetetramethylenephosphonic acid, and polyurethane prepolymer were mixed, heated, and stirred at 40°C to obtain a mixture. The mixture was then injected into a mold at 70°C for molding, demolded, and cured at 80°C for 24 hours. After grinding and cleaning, a polyurethane elastomer for use in rail energy-consuming components was obtained.

[0035] Example 3: Polyurethane elastomer for energy-consuming components of rails and its preparation process, including the following steps:

[0036] Preparation of components: 13 parts by weight of modified stabilizer, 55 parts by weight of L-lysine diisocyanate, 95 parts by weight of polyadipate polyol, 1.5 parts by weight of dibutyltin dilaurate catalyst, 5 parts by weight of 1,4-butanediol chain extender, 25 parts by weight of silica filler, 0.5 parts by weight of 2,6-di-tert-butyl-p-cresol antioxidant, and Chimassorb. The mixture comprises 0.3 parts by weight of hindered amine light stabilizer 2020, 1 part by weight of ethylenediaminetetramethylenephosphonic acid, and 1 part by weight of KH-550 silane coupling agent; wherein the modified stabilizer is prepared by lauric acid and (R)-2-amino-3-(phenylseleno)propionic acid in a mass ratio of 1:1.1; the mass concentration of lauryl alcohol solution is 7 mg / mL, the mass concentration of (R)-2-amino-3-(phenylseleno)propionic acid solution is 14 mg / mL; the molar ratio of dicyclohexylcarbodiimide to (R)-2-amino-3-(phenylseleno)propionic acid is 1.2:1; and the molar ratio of 4-dimethylaminopyridine to (R)-2-amino-3-(phenylseleno)propionic acid is 0.12:1.

[0037] Lauryl alcohol was dissolved in dichloromethane to prepare a lauryl alcohol solution. (R)-2-amino-3-(phenylseleno)propionic acid was dissolved separately in dichloromethane to obtain a (R)-2-amino-3-(phenylseleno)propionic acid solution. Dicyclohexylcarbodiimide was added to the (R)-2-amino-3-(phenylseleno)propionic acid solution, and the mixture was stirred in an ice bath for 30 min. Then, 4-dimethylaminopyridine was added, and the mixture was stirred for another 15 min. Lauryl alcohol solution was added dropwise, and the mixture was heated to 40 °C and reacted for 4 h. The activation degree of the carboxylic acid was monitored by thin-layer chromatography to confirm the carboxylic acid spots. When the ester product spots began to appear, the mixture was filtered and washed with 5% (v / v) dilute hydrochloric acid, dried over 10% (w / v) anhydrous sodium sulfate, and the solvent was removed by rotary evaporation. The mixture was then purified by silica gel column chromatography to obtain the modified stabilizer.

[0038] L-lysine diisocyanate, polyadipate polyol, and modified stabilizer were mixed and reacted in a water bath at 60°C to obtain a polyurethane prepolymer. The mixture was continuously stirred with a magnetic stirrer at a speed of 400 rpm / min for 3 hours. Dibutyltin dilaurate catalyst, 1,4-butanediol chain extender, silica filler, 2,6-di-tert-butyl-p-cresol antioxidant, Chimassorb 2020 hindered amine light stabilizer, and KH-550 silane coupling agent were mixed and vacuum dehydrated at 120°C to a moisture content of less than 0.05%. The mixture, ethylenediaminetetramethylenephosphonic acid, and polyurethane prepolymer were mixed, heated, and stirred at 40°C to obtain a mixture. The mixture was then injected into a mold at 70°C for molding, demolded, and cured at 80°C for 24 hours. After grinding and cleaning, a polyurethane elastomer for use in rail energy-consuming components was obtained.

[0039] Example 4: Polyurethane elastomer for energy-consuming components of rails and its preparation process, including the following steps:

[0040] Preparation of components: 13 parts by weight of modified stabilizer, 65 parts by weight of L-lysine diisocyanate, 110 parts by weight of polyadipate polyol, 2.5 parts by weight of dibutyltin dilaurate catalyst, 10 parts by weight of 1,4-butanediol chain extender, 30 parts by weight of silica filler, 1.0 part by weight of 2,6-di-tert-butyl-p-cresol antioxidant, and Chimassorb. The mixture comprises 0.6 parts by weight of hindered amine light stabilizer (2020), 10 parts by weight of ethylenediaminetetramethylenephosphonic acid (EDTA), and 3 parts by weight of KH-550 silane coupling agent. The modified stabilizer is prepared from lauric acid and (R)-2-amino-3-(phenylseleno)propionic acid at a mass ratio of 1:0.8. The lauryl alcohol solution has a mass concentration of 9 mg / mL, and the (R)-2-amino-3-(phenylseleno)propionic acid solution has a mass concentration of 16 mg / mL. The molar ratio of dicyclohexylcarbodiimide to (R)-2-amino-3-(phenylseleno)propionic acid is 1.2:1; the molar ratio of 4-dimethylaminopyridine to (R)-2-amino-3-(phenylseleno)propionic acid is 0.12:1.

[0041] Lauryl alcohol was dissolved in dichloromethane to prepare a lauryl alcohol solution. (R)-2-amino-3-(phenylseleno)propionic acid was dissolved separately in dichloromethane to obtain a (R)-2-amino-3-(phenylseleno)propionic acid solution. Dicyclohexylcarbodiimide was added to the (R)-2-amino-3-(phenylseleno)propionic acid solution, and the mixture was stirred in an ice bath for 30 min. Then, 4-dimethylaminopyridine was added, and the mixture was stirred for another 15 min. Lauryl alcohol solution was added dropwise, and the mixture was heated to 40 °C and reacted for 4 h. The activation degree of the carboxylic acid was monitored by thin-layer chromatography to confirm the carboxylic acid spots. When the ester product spots began to appear, the mixture was filtered and washed with 5% (v / v) dilute hydrochloric acid, dried over 10% (w / v) anhydrous sodium sulfate, and the solvent was removed by rotary evaporation. The mixture was then purified by silica gel column chromatography to obtain the modified stabilizer.

[0042] L-lysine diisocyanate, polyadipate polyol, and modified stabilizer were mixed and reacted in a water bath at 60°C to obtain a polyurethane prepolymer. The mixture was continuously stirred with a magnetic stirrer at a speed of 400 rpm / min for 3 hours. Dibutyltin dilaurate catalyst, 1,4-butanediol chain extender, silica filler, 2,6-di-tert-butyl-p-cresol antioxidant, Chimassorb 2020 hindered amine light stabilizer, and KH-550 silane coupling agent were mixed and vacuum dehydrated at 120°C to a moisture content of less than 0.05%. The mixture, ethylenediaminetetramethylenephosphonic acid, and polyurethane prepolymer were mixed, heated, and stirred at 40°C to obtain a mixture. The mixture was then injected into a mold at 70°C for molding, demolded, and cured at 80°C for 24 hours. After grinding and cleaning, a polyurethane elastomer for use in rail energy-consuming components was obtained.

[0043] Example 5: Polyurethane elastomer for energy-consuming components of rails and its preparation process, including the following steps:

[0044] Preparation of components: 10 parts by weight of modified stabilizer, 55 parts by weight of L-lysine diisocyanate, 95 parts by weight of polyadipate polyol, 1.5 parts by weight of dibutyltin dilaurate catalyst, 5 parts by weight of 1,4-butanediol chain extender, 25 parts by weight of silica filler, 0.5 parts by weight of 2,6-di-tert-butyl-p-cresol antioxidant, and Chimassorb. The mixture comprises 0.3 parts by weight of hindered amine light stabilizer 2020, 1 part by weight of ethylenediaminetetramethylenephosphonic acid, and 1 part by weight of KH-550 silane coupling agent; wherein the modified stabilizer is prepared by lauric acid and (R)-2-amino-3-(phenylseleno)propionic acid in a mass ratio of 1:0.8; the mass concentration of lauryl alcohol solution is 7 mg / mL, and the mass concentration of (R)-2-amino-3-(phenylseleno)propionic acid solution is 14 mg / mL; the molar ratio of dicyclohexylcarbodiimide to (R)-2-amino-3-(phenylseleno)propionic acid is 1.2:1; and the molar ratio of 4-dimethylaminopyridine to (R)-2-amino-3-(phenylseleno)propionic acid is 0.12:1.

[0045] Lauryl alcohol was dissolved in dichloromethane to prepare a lauryl alcohol solution. (R)-2-amino-3-(phenylseleno)propionic acid was dissolved separately in dichloromethane to obtain a (R)-2-amino-3-(phenylseleno)propionic acid solution. Dicyclohexylcarbodiimide was added to the (R)-2-amino-3-(phenylseleno)propionic acid solution, and the mixture was stirred in an ice bath for 30 min. Then, 4-dimethylaminopyridine was added, and the mixture was stirred for another 15 min. Lauryl alcohol solution was added dropwise, and the mixture was heated to 40 °C and reacted for 4 h. The activation degree of the carboxylic acid was monitored by thin-layer chromatography to confirm the carboxylic acid spots. When the ester product spots began to appear, the mixture was filtered and washed with 5% (v / v) dilute hydrochloric acid, dried over 10% (w / v) anhydrous sodium sulfate, and the solvent was removed by rotary evaporation. The mixture was then purified by silica gel column chromatography to obtain the modified stabilizer.

[0046] L-lysine diisocyanate, polyadipate polyol, and modified stabilizer were mixed and reacted in a water bath at 60°C to obtain a polyurethane prepolymer. The mixture was continuously stirred with a magnetic stirrer at a speed of 400 rpm / min for 3 hours. Dibutyltin dilaurate catalyst, 1,4-butanediol chain extender, silica filler, 2,6-di-tert-butyl-p-cresol antioxidant, Chimassorb 2020 hindered amine light stabilizer, and KH-550 silane coupling agent were mixed and vacuum dehydrated at 120°C to a moisture content of less than 0.05%. The mixture, ethylenediaminetetramethylenephosphonic acid, and polyurethane prepolymer were mixed, heated, and stirred at 40°C to obtain a mixture. The mixture was then injected into a mold at 70°C for molding, demolded, and cured at 80°C for 24 hours. After grinding and cleaning, a polyurethane elastomer for use in rail energy-consuming components was obtained.

[0047] Example 6: A polyurethane elastomer for energy-consuming components of rails and its preparation process, comprising the following steps:

[0048] Preparation of components: 15 parts by weight of modified stabilizer, 55 parts by weight of L-lysine diisocyanate, 95 parts by weight of polyadipate polyol, 1.5 parts by weight of dibutyltin dilaurate catalyst, 5 parts by weight of 1,4-butanediol chain extender, 25 parts by weight of silica filler, 0.5 parts by weight of 2,6-di-tert-butyl-p-cresol antioxidant, and Chimassorb. The mixture comprises 0.3 parts by weight of hindered amine light stabilizer 2020, 1 part by weight of ethylenediaminetetramethylenephosphonic acid, and 1 part by weight of KH-550 silane coupling agent; wherein the modified stabilizer is prepared by lauric acid and (R)-2-amino-3-(phenylseleno)propionic acid in a mass ratio of 1:0.8; the mass concentration of lauryl alcohol solution is 7 mg / mL, and the mass concentration of (R)-2-amino-3-(phenylseleno)propionic acid solution is 14 mg / mL; the molar ratio of dicyclohexylcarbodiimide to (R)-2-amino-3-(phenylseleno)propionic acid is 1.2:1; and the molar ratio of 4-dimethylaminopyridine to (R)-2-amino-3-(phenylseleno)propionic acid is 0.12:1.

[0049] Lauryl alcohol was dissolved in dichloromethane to prepare a lauryl alcohol solution. (R)-2-amino-3-(phenylseleno)propionic acid was dissolved separately in dichloromethane to obtain a (R)-2-amino-3-(phenylseleno)propionic acid solution. Dicyclohexylcarbodiimide was added to the (R)-2-amino-3-(phenylseleno)propionic acid solution, and the mixture was stirred in an ice bath for 30 min. Then, 4-dimethylaminopyridine was added, and the mixture was stirred for another 15 min. Lauryl alcohol solution was added dropwise, and the mixture was heated to 40 °C and reacted for 4 h. The activation degree of the carboxylic acid was monitored by thin-layer chromatography to confirm the carboxylic acid spots. When the ester product spots began to appear, the mixture was filtered and washed with 5% (v / v) dilute hydrochloric acid, dried over 10% (w / v) anhydrous sodium sulfate, and the solvent was removed by rotary evaporation. The mixture was then purified by silica gel column chromatography to obtain the modified stabilizer.

[0050] L-lysine diisocyanate, polyadipate polyol, and modified stabilizer were mixed and reacted in a water bath at 60°C to obtain a polyurethane prepolymer. The mixture was continuously stirred with a magnetic stirrer at a speed of 400 rpm / min for 3 hours. Dibutyltin dilaurate catalyst, 1,4-butanediol chain extender, silica filler, 2,6-di-tert-butyl-p-cresol antioxidant, Chimassorb 2020 hindered amine light stabilizer, and KH-550 silane coupling agent were mixed and vacuum dehydrated at 120°C to a moisture content of less than 0.05%. The mixture, ethylenediaminetetramethylenephosphonic acid, and polyurethane prepolymer were mixed, heated, and stirred at 40°C to obtain a mixture. The mixture was then injected into a mold at 70°C for molding, demolded, and cured at 80°C for 24 hours. After grinding and cleaning, a polyurethane elastomer for use in rail energy-consuming components was obtained.

[0051] Comparative Example 1: Polyurethane elastomers were prepared using the method of Example 2 without the addition of a modifier or stabilizer.

[0052] Comparative Example 2: Using the method of Example 2, (R)-2-amino-3-(phenylseleno)propionic acid was directly added to the preparation process of polyurethane elastomer without reacting with lauric acid to prepare a modified stabilizer.

[0053] Comparative Example 3: Using the method of Example 2, lauryl alcohol was directly added to the preparation process of polyurethane elastomer without reacting with (R)-2-amino-3-(phenylseleno)propionic acid to prepare a modified stabilizer.

[0054] This invention relates to a polyurethane elastomer for energy-consuming components of rails, prepared using a modified stabilizer. The performance indicators and testing standards for this polyurethane elastomer for rail energy-consuming components are as follows:

[0055] According to the test methods in GB / T 528-2009 "Determination of Tensile Stress-Strain Properties of Vulcanized Rubber or Thermoplastic Rubber", the tensile strength and elongation at break are tested to reflect the flexibility of the material. Then, samples of the same size are placed in an ultraviolet (UV) aging chamber for 24 hours. The UV aging chamber uses UV-B lamps with a light intensity of 0.65 W / m² / nm@340nm, a temperature of 80℃, and a humidity of 95%. After the predetermined aging time, the test is stopped, and the samples are removed for performance testing. By comparing the tensile strength data before and after aging, the degree of performance degradation is calculated, and the aging rate of the material is evaluated. Tensile strength change rate = (tensile strength before treatment - tensile strength after treatment) / (tensile strength before treatment) × 100%, aging rate = tensile strength change rate ÷ aging time; Immerse samples of the same size and specifications in a 5% sulfuric acid solution for 24 hours, ensuring that the sample surface is fully in contact with the reagent. Remove the samples from the reagent and rinse them thoroughly with clean water to remove any residual reagent. Place the cleaned samples in a ventilated place to air dry naturally. After drying, measure the tensile strength of the samples again, compare the changes in physical properties of the samples before and after immersion, and calculate the rate of change of properties. Tensile strength change rate = (tensile strength after treatment - tensile strength before treatment) / (tensile strength before treatment) × 100%.

[0056] The polyurethane elastomers for rail energy-consuming components prepared in Examples 1-6 and Comparative Examples 1-3 were tested according to the above standards, and the data obtained are shown in Table 1:

[0057] Table 1 Performance data of Examples 1-6 and Comparative Examples 1-3

[0058]

[0059] The above data fully demonstrate that, compared with Comparative Examples 1-3, Examples 1-6 clearly show the effect of the modified stabilizer on the mechanical properties, chemical stability, and anti-aging properties of polyurethane elastomers used in rail energy-consuming components.

[0060] Because this invention uses a modified stabilizer to prepare a polyurethane elastomer for rail energy-consuming components, the performance of the polyurethane elastomer for rail energy-consuming components is effectively improved by the modified stabilizer, as follows:

[0061] As can be seen from Examples 1-3, with the continuous change of the component ratio in the modified stabilizer, the mechanical properties, chemical stability, and anti-aging properties of the polyurethane elastomer used in rail energy-consuming components first increase and then decrease. This is because with the continuous increase of the content of (R)-2-amino-3-(phenylselenopropionic acid) in the modified stabilizer, selenium has an antioxidant effect, which can scavenge free radicals and reduce the aging of materials. Furthermore, the introduction of phenyl and fatty acid groups can regulate the mobility of chain segments and balance the hardness and flexibility of the material, thus improving the overall performance of the polyurethane elastomer. However, excessive addition of (R)-2-amino-3-(phenylselenopropionic acid) will lead to an increase in the phenyl content, making the polyurethane material more rigid, thereby reducing its flexibility and mechanical properties.

[0062] As can be seen from Examples 2 and 4, as the component content in the polyurethane elastomer changes continuously, the mechanical properties, chemical stability, and anti-aging properties of the polyurethane elastomer used in rail energy-consuming components do not change significantly. This indicates that small changes in other components within a certain range, and with consistent magnitudes, will not have a significant impact on the performance of the polyurethane elastomer.

[0063] As can be seen from Examples 2, 5, and 6, the mechanical properties, chemical stability, and anti-aging properties of the polyurethane elastomer used in rail energy-consuming components change continuously with the continuous change of the content of modified stabilizer in the polyurethane elastomer. This is because (R)-2-amino-3-(phenylselenopropionic acid) in the modified stabilizer helps to enhance the stability, mechanical properties, and anti-aging properties of the material, and fatty acid groups help to enhance the hydrophobicity of the material and reduce water erosion. However, excessive modified stabilizer will result in too many active groups in the modified stabilizer, which will lead to excessive cross-linking with isocyanate groups, thereby affecting the process of preparing polyurethane from isocyanate and polyol and reducing the performance of the material.

[0064] Based on the above test experiments, it can be seen that the polyurethane elastomer for rail energy-consuming components prepared according to Example 2 has the best performance, so Example 2 is regarded as the best example.

[0065] A comparison of Example 2 with Comparative Examples 1-3 shows that:

[0066] Comparative Example 1 shows that polyurethane elastomers prepared without the addition of modified stabilizers have poorer mechanical properties, chemical stability, and anti-aging properties when used in rail energy-consuming components. This is because modified stabilizers can balance the hardness and flexibility of the material through fatty acid groups and phenyl groups, allowing it to maintain a certain level of hardness without losing elasticity. At the same time, selenium has strong antioxidant capabilities, which can scavenge free radicals and reduce material aging. Without modified stabilizers, the hydrophobicity of the polyurethane elastomers deteriorates, and the material is more prone to absorbing water and swelling, leading to a decline in performance.

[0067] In Comparative Example 2, (R)-2-amino-3-(phenylseleno)propionic acid was directly added to the preparation process of polyurethane elastomer without reacting with lauryl alcohol to prepare a modified stabilizer. The mechanical properties, chemical stability, and anti-aging properties of the polyurethane elastomer used in rail energy-consuming components were poor. This is because the direct addition of (R)-2-amino-3-(phenylseleno)propionic acid, due to the presence of the phenyl group on (R)-2-amino-3-(phenylseleno)propionic acid, caused the material to become too rigid, thus affecting the overall performance of the material.

[0068] In Comparative Example 3, lauryl alcohol was directly added to the preparation process of polyurethane elastomer without reacting with (R)-2-amino-3-(phenylseleno)propionic acid to prepare a modified stabilizer. The mechanical properties, chemical stability, and anti-aging properties of the polyurethane elastomer used in rail energy-consuming components were poor. This is because lauryl alcohol can improve the flexibility of polyurethane, and the longer branches will make the material too soft, affecting the overall performance of the material.

[0069] In summary, by modifying the phenyl groups on (R)-2-amino-3-(phenylseleno)propionic acid and the fatty acid groups on lauryl alcohol in the stabilizer, the flexibility and rigidity of the material are balanced, promoting the improvement of the mechanical properties of polyurethane elastomers. At the same time, the phenyl group provides stability, the fatty acid group provides hydrophobicity, and the selenium element has antioxidant properties, which improves the anti-aging, water resistance, and chemical stability of polyurethane elastomers, thereby improving the durability and service life of polyurethane elastomers. L-Lysine diisocyanate.

[0070] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A polyurethane elastomer for energy-consuming components of steel rails, characterized in that: The product comprises the following components: 10-15 parts by weight of modified stabilizer, 55-65 parts by weight of L-lysine diisocyanate, 95-110 parts by weight of polyadipate polyol, 1.5-2.5 parts by weight of dibutyltin dilaurate catalyst, 5-10 parts by weight of 1,4-butanediol chain extender, 25-30 parts by weight of silica filler, 0.5-1.0 parts by weight of 2,6-di-tert-butyl-p-cresol antioxidant, 0.3-0.6 parts by weight of Chimassorb 2020 hindered amine light stabilizer, 1-10 parts by weight of ethylenediaminetetramethylenephosphonic acid, and 1-3 parts by weight of KH-550 silane coupling agent; The modified stabilizer is prepared by lauryl alcohol and (R)-2-amino-3-(phenylseleno)propionic acid in a mass ratio of 1:0.5 to 1.

1.

2. The polyurethane elastomer for energy-consuming components of steel rails according to claim 1, characterized in that: The modified stabilizer is prepared as follows: Lauryl alcohol was dissolved in dichloromethane to prepare a lauryl alcohol solution. (R)-2-amino-3-(phenylseleno)propionic acid was dissolved separately in dichloromethane to obtain a (R)-2-amino-3-(phenylseleno)propionic acid solution. Dicyclohexylcarbodiimide was added to the (R)-2-amino-3-(phenylseleno)propionic acid solution, and the mixture was stirred in an ice bath for 25-30 min. Then, 4-dimethylaminopyridine was added, and the mixture was stirred for another 10-15 min. Lauryl alcohol solution was added dropwise, and the temperature was raised to 40-45℃. The reaction was carried out for 4-6 h. The activation degree of the carboxylic acid was monitored by thin-layer chromatography to confirm the carboxylic acid spots. When the ester product spots began to appear, the mixture was filtered and washed with 3-5% (v / v) dilute hydrochloric acid. The mixture was dried over 5-10% (w / v) anhydrous sodium sulfate, and the solvent was removed by rotary evaporation. The mixture was then purified by silica gel column chromatography to obtain the modified stabilizer.

3. The polyurethane elastomer for energy-consuming components of steel rails according to claim 2, characterized in that: The lauryl alcohol solution has a mass concentration of 7-9 mg / mL.

4. The polyurethane elastomer for energy-consuming components of steel rails according to claim 2, characterized in that: The mass concentration of the (R)-2-amino-3-(phenylseleno)propionic acid solution is 14-16 mg / mL.

5. The polyurethane elastomer for energy-consuming components of steel rails according to claim 2, characterized in that: The molar ratio of the dicyclohexylcarbodiimide to (R)-2-amino-3-(phenylseleno)propionic acid is 1.1 to 1.3:

1.

6. The polyurethane elastomer for energy-consuming components of steel rails according to claim 2, characterized in that: The molar ratio of 4-dimethylaminopyridine to (R)-2-amino-3-(phenylseleno)propionic acid is 0.1 to 0.15:

1.

7. A process for preparing a polyurethane elastomer for energy-consuming components of rails, used to prepare the polyurethane elastomer for energy-consuming components of rails as described in any one of claims 1-6, characterized in that: Includes the following steps: L-lysine diisocyanate, polyadipate polyol, and modified stabilizer are mixed and reacted in a water bath at 60-80℃ to obtain a polyurethane prepolymer. The mixture is continuously stirred with a magnetic stirrer at a speed of 200-400 rpm / min for 2-3 hours. Dibutyltin dilaurate catalyst, 1,4-butanediol chain extender, silica filler, 2,6-di-tert-butyl-p-cresol antioxidant, Chimassorb 2020 hindered amine light stabilizer, and KH-550 silane coupling agent are mixed and vacuum dehydrated at 100-120℃. The mixture, ethylenediaminetetramethylenephosphonic acid, and polyurethane prepolymer are then mixed, heated, and stirred at 40-50℃ to obtain a compound. The compound is then injected into a mold and molded at 70-75℃. After demolding, curing, grinding, and cleaning, a polyurethane elastomer for use in rail energy-consuming components is obtained.

8. The preparation process of the polyurethane elastomer for energy-consuming components of rails according to claim 7, characterized in that: The polyadipate polyol is polybutylene adipate.

9. The preparation process of the polyurethane elastomer for energy-consuming components of rails according to claim 7, characterized in that: The mixture after vacuum dehydration has a moisture content of less than 0.05%.

10. The preparation process of the polyurethane elastomer for energy-consuming components of rails according to claim 7, characterized in that: The curing temperature is 80-85℃, and the curing time is 24-32h.

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