Low temperature resistant polyurethane elastomers and methods for making the same

Abstract

The application belongs to the technical field of polyurethane elastomer materials, and particularly relates to a low-temperature-resistant polyurethane elastomer and a preparation method thereof. The polyurethane elastomer material is composed of components A and B, and the mass ratio of the components A and B is (0.02-1):1. The component A is a curing agent component, which is physically mixed from polyhydric alcohol 1, a chain extension crosslinking agent and an organic metal catalyst, and the mass ratio is 100:0-200:0.01-1.0. The component B is a prepolymer component, which is obtained by the reaction of polyether polyol 2, epoxy resin, organic amine and polyisocyanate, and the mass ratio is 100:8-55:1.5-10:10-150. The polyurethane elastomer provided by the application has excellent mechanical properties, and the glass transition temperature reaches-80 to-50 DEG C, and the low-temperature resistance is excellent.

Description

Technical Field

[0001] This invention belongs to the field of polyurethane elastomer material technology, and particularly relates to a low-temperature resistant polyurethane elastomer material and its preparation method. Background Technology

[0002] Polyurethane elastomer (TPU) possesses a unique structure of soft and hard block copolymers, which endows its products with excellent comprehensive mechanical properties: superior mechanical properties, wear resistance, oil resistance, aging resistance, and a wide range of adjustable hardness. These excellent comprehensive properties are not found in many other commercially available rubbers and plastics, making TPU the preferred material in many application fields. To keep pace with societal progress and rapid technological development, the requirements for the use of polyurethane elastomers are becoming increasingly stringent. While polyether-type polyurethane elastomers have good low-temperature resistance, due to their molecular structure, the molecular chains undergo significant crystallization at extreme low temperatures. This manifests as a sharp increase in hardness, loss of elasticity, and a drastic decrease in the compressive cold resistance coefficient. When used as a sealant in such low-temperature environments, oil leakage is highly likely due to low-temperature crystallization, severely limiting the application of TPU. Therefore, maintaining the high elasticity of TPU at low temperatures is a primary research task. Polyester-based TPU has higher strength, abrasion resistance, and oil resistance, but its hydrolysis resistance and low-temperature resistance are relatively poor, and its physical properties drop sharply at low temperatures. Polyether-based TPU has better flexibility, but its physical and mechanical properties are poor, especially its mechanical properties at low temperatures, which cannot meet the requirements of some applications with high mechanical performance. However, there is currently no preparation method that can simultaneously improve the flexibility and mechanical properties of thermoplastic polyurethane at low temperatures.

[0003] Patent CN105482055A discloses a low-temperature resistant polyurethane elastomer and its preparation method. It uses polyester polyol and MDI to synthesize a prepolymer, and small molecule chain extenders or crosslinking agents as curing agents. The final prepared sample exhibits good low-temperature resistance, with a glass transition temperature of -50 to -20°C and a low-temperature hardness of 70A to 100A Shore A. However, this technology has the following drawbacks: ① The polyol raw material used is polyester polyol, which is costly; ② During the preparation of component A (prepolymer), the polyester polyol and plasticizer are not dehydrated, resulting in an uncertain NCO value for the prepolymer, which may lead to significant differences in the molecular structure of the subsequently synthesized elastomer; ③ When using plasticizers, a certain degree of phase separation may occur, affecting the performance of the elastomer.

[0004] Patent CN107254161A discloses a two-component low-temperature resistant polyurethane elastomer and its preparation method. It uses oligomeric polyols and polyisocyanates to prepare a prepolymer, and a small-molecule chain extender / crosslinker as the curing system. The final sample exhibits good low-temperature resistance, and its hardness does not change significantly compared to room temperature. This technology improves the flexibility of the molecular chain by introducing organosilicon into the main chain. However, the examples used dimethyl silicone oil, which lacks groups capable of reacting with isocyanates or polyols. Therefore, this technology merely blends dimethyl silicone oil with the polymer, resulting in easy transfer of the dimethyl silicone oil and poor softening effect.

[0005] Patent CN111205426A discloses a method for preparing a low-temperature resistant polyurethane elastomer, using a mixture of caprolactone diol and hydroxyl-terminated polyallyl glycidyl ether-polybutanediol-polyallyl glycidyl ether triblock copolymer ether as the soft segment, and coating the surface of nano-titanium dioxide with ferric hydroxide. This technology uses triblock copolymer ether as the main soft segment structure; however, this triblock polymer is synthesized using a cationic polymerization mechanism, which involves harsh synthesis conditions, a complex polymerization mechanism, and is prone to side reactions such as chain transfer and isomerization, resulting in an unstable product structure that ultimately affects the elastomer's performance.

[0006] Therefore, developing a polyurethane elastomer material with excellent physical and mechanical properties and low-temperature resistance is one of the problems that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0007] To address the numerous shortcomings of existing technologies, this invention provides a low-temperature resistant polyurethane elastomer material and its preparation method. The polyurethane elastomer material comprises component A and component B, with a mass ratio of A to B of (0.02–1):1. Component A is a curing agent component, formed by the physical mixing of polyol 1, a chain extender / crosslinker, and a catalyst. Component B is a prepolymer component, obtained by reacting polyether polyol 2, epoxy resin, organic amine, and polyisocyanate. The polyurethane elastomer provided by this invention exhibits excellent mechanical properties, and its glass transition temperature T0 is high. g It reaches -80 to -50℃, demonstrating excellent low-temperature resistance.

[0008] The mechanism of this invention is as follows: By introducing epoxy resin into the main molecular chain of the polyurethane prepolymer, the epoxy resin acts as a reinforcing agent for the polyurethane material. Combined with the high strength of the cured epoxy resin, the flexible polyurethane molecular chains and the rigid epoxy resin molecular chains interpenetrate, and the reactive groups between the two components form an interpenetrating network structure through chemical reaction. This significantly improves the tensile strength and elongation at break of the polymer material. Furthermore, this invention optimizes the polyurethane formulation, controlling the proportion of soft segments in the polyurethane by controlling the NCO value of the prepolymer (NCO% adjustable within the range of 4.50% to 23.00%), and changing the type of polyol to control the type of soft segments, thereby improving the toughness and cold resistance of the material.

[0009] The specific technical solution of the present invention is as follows: A low-temperature resistant polyurethane elastomer material is composed of component A and component B, with a mass ratio of component A to component B of (0.02 to 1):1.

[0010] Component A is a curing agent component, which is formed by physically mixing polyol 1, chain extender and crosslinker and catalyst, with a mass ratio of 100:0 to 200:0.01 to 1.0, preferably 100:30 to 150:0.1 to 0.6.

[0011] More preferably, the composition of component A, by mass parts, is as follows: Polyol 1 100 parts, 85.71 parts of chain extender / crosslinker, 0.15 parts catalyst.

[0012] The polyol 1 is one or a combination of polyether DL-1000, 1,4-butanediol, polyether DL-2000, and PTMG-1000. The chain extender / crosslinker is one or more of 3,3'-dichloro-4,4'-diaminodiphenylmethane (MOCA), triethanolamine, diethyltoluenediamine, 2,4-diamino-3,5-dimethylthiotoluene, and trimethylolpropane. The catalyst is one or a combination of organobismuth, organotin, organozinc, organolead, and organic amines.

[0013] Component B is a prepolymer component, which is obtained by reacting polyether polyol 2, epoxy resin, organic amine and polyisocyanate, with a mass ratio of 100:8-55:1.5-10:10-150, preferably 100:10-50:3.5-8.5:20-140.

[0014] More preferably, the composition of component B, by mass parts, is as follows: Polyether polyol 2, 100 parts 45 parts epoxy resin Organic amines: 6.2 parts 138 parts of polyisocyanate.

[0015] The polyether polyol 2 is one or a combination of polyether DL-2000, polyether DL-1000, polyether 330N, PTMG-1000, PPG-1000 and HB-80; the epoxy resin is one of E-51, E-20, E-44 and E-68; the organic amine is one of 1,6-hexanediamine, ethylenediamine, diethyltoluenediamine, and 2,4-diamino-3,5-dimethylthiotoluene; and the polyisocyanate is one of toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and polymethylene polyphenyl isocyanate.

[0016] Preferably, the polyether polyol 2 is two or more combinations of polyether DL-2000, polyether DL-1000 and HB-80; the epoxy resin is one of E-51, E-20 and E-44; the organic amine is one of 1,6-hexanediamine, ethylenediamine, and 2,4-diamino-3,5-dimethylthiotoluene; and the polyisocyanate is one of toluene diisocyanate and diphenylmethane diisocyanate.

[0017] The glass transition temperature of the low-temperature resistant polyurethane elastomer material obtained above is -80 to -50℃.

[0018] Furthermore, the present invention provides a method for preparing the above-mentioned low-temperature resistant polyurethane elastomer material, the specific steps of which are as follows: (1) Mix polyol 1, chain extender and catalyst in proportion, and dehydrate at 100-120℃ and vacuum degree of 0.05-0.1MPa for 1-2 hours under stirring at 250-400 rpm until the moisture content is below 0.05wt%. After depressurization and cooling to room temperature, seal and store to obtain curing agent component, i.e. component A. (2) Polyether polyol 2 and epoxy resin are dehydrated for 1 to 2 hours under stirring at 300 to 400 rpm and at 100 to 120°C and vacuum of 0.05 to 0.10 MPa until the moisture content is below 0.05 wt%. Nitrogen gas is then added to depressurize and the temperature is lowered to 30 to 60°C. Then organic amine is added and reacted at 250 to 350 rpm for 1 to 3 hours. After the reaction is complete, polyisocyanate is added and the temperature is raised to 70 to 90°C to continue the reaction for 1.5 to 2.5 hours. The NCO% is controlled within the range of 4.50% to 23.00% to obtain the prepolymer component, i.e. component B, which is protected by nitrogen gas for later use. (3) Mix component A and component B in proportion and stir at 300-1000 rpm for 20-40 seconds using a high-speed mixer. Pour the mixture into a mold and cure it at 80-100℃. Demold it after 20-60 minutes and vulcanize it at 70-90℃ for 8-14 hours to obtain a low-temperature resistant polyurethane elastomer.

[0019] In the technical solution of this invention, component A is a physical mixture, with no chemical reaction occurring between its components, and their chemical properties are almost unaffected by each other. Component B is a prepolymer, in which epoxy resin undergoes a ring-opening reaction with organic amine to produce hydroxyl groups; polyether alcohol and epoxy resin produce hydroxyl groups, and excess polyisocyanate undergoes a grafting reaction to form an interpenetrating network structure. This structure significantly improves the comprehensive mechanical properties of the polymer material, thereby enhancing the material's service life and application range, and is accompanied by a certain amount of free isocyanate. Finally, the active hydroxyl groups provided by the polyether polyol in component A and the aromatic amine groups provided by the chain extender and crosslinking agent react with the free isocyanate in component B under the action of a catalyst to generate a polyurethane elastomer material. The soft segment of the polyurethane elastomer material is mainly composed of polyol and epoxy resin, while the hard segment is mainly composed of polyisocyanate, benzene rings present in some polyols, and aromatic amines.

[0020] Compared with the prior art, the present invention has achieved the following beneficial effects: This invention introduces epoxy resin as a reinforcing agent onto the main chain of polyurethane molecules, resulting in a low-temperature resistant polyurethane elastomer with excellent mechanical properties. Furthermore, by selecting polyols with good molecular chain flexibility from the polyols used in the synthesis of polyurethane, a glass transition temperature T0 is achieved. g It reaches temperatures of -80 to -50℃, exhibits excellent low-temperature resistance, and is suitable for low-temperature applications. Detailed Implementation

[0021] The invention will be further illustrated below with specific implementation examples. These examples are only for further elaboration of the invention and are not intended to represent all implementation examples. All other implementation examples created based on this invention are within the scope of protection of this invention. Unless otherwise specified, conventional techniques are used in the following embodiments.

[0022] Example 1: A low-temperature resistant polyurethane elastomer material and its preparation method, the specific steps of which are as follows: (1) Mix 25g DL-1000, 20g triethanolamine, 15g 1,4-butanediol and 0.075g dibutyltin dilaurate, and dehydrate at 110℃ and 0.05MPa under stirring at 300rpm until the moisture content is below 0.05wt%. Then depressurize, cool to room temperature and seal to obtain curing agent component, i.e. component A. (2) 100g HB-80 and 30g epoxy resin E-51 were stirred at 350rpm and dehydrated at 110℃ and 0.05MPa for 1 hour until the moisture content was below 0.05wt%. Nitrogen gas was then added to depressurize and cool to 40℃. 8g 1,6-hexanediamine was then added and reacted at 350rpm for 2.5h. After the reaction was completed, 27g toluene diisocyanate was added and the temperature was raised to 80℃ and the reaction was continued for 2h to obtain a prepolymer with NCO%=7.70%, i.e. component B. Nitrogen gas was then used for protection.

[0023] (3) Mix the prepared components A and B at a mass ratio of 0.04:1, stir at 400 rpm for 30 seconds using a high-speed mixer, pour into a mold, cure at 80°C, demold after 60 min, and vulcanize at 80°C for 12 h to obtain a low-temperature resistant polyurethane elastomer.

[0024] Example 2: A low-temperature resistant polyurethane elastomer material and its preparation method, the specific steps of which are as follows: (1) Mix 30g DL-2000, 15g triethanolamine, 15g 1,4-butanediol and 0.075g dibutyltin dilaurate, and dehydrate at 110℃ and 0.05MPa under stirring at 275rpm until the moisture content is below 0.05wt%. Then depressurize, cool to room temperature and seal to obtain curing agent component, i.e. component A; (2) 100g HB-80 and 20g epoxy resin E-20 were dehydrated for 1.5 hours at 105℃ and 0.05MPa under stirring at 350rpm until the moisture content was below 0.05wt%. Nitrogen gas was then added to depressurize and the temperature was lowered to 30℃. 3.2g diethyltoluene diamine was then added and the mixture was stirred at 300rpm for 1.5h. After the reaction was completed, 30g toluene diisocyanate was added and the temperature was raised to 80℃ for another 1.5h to obtain a prepolymer with NCO%=9.38%, i.e. component B. Nitrogen gas was then used for protection. (3) Mix the prepared components A and B at a mass ratio of 0.14:1, stir at 350 rpm for 40 seconds using a high-speed mixer, pour into a mold, cure at 80°C, demold after 50 min, and vulcanize at 80°C for 14 h to obtain a low-temperature resistant polyurethane elastomer.

[0025] Example 3: A low-temperature resistant polyurethane elastomer material and its preparation method, the specific steps of which are as follows: (1) Mix 50g DL-2000, 5g 1,4-butanediol, 45g triethanolamine and 0.075g dibutyltin dilaurate, and dehydrate at 110℃ and 0.05MPa for 2 hours under stirring at 350rpm until the moisture content is below 0.05wt%. After depressurization and cooling to room temperature, seal and store to obtain the curing agent component, i.e. component A; (2) 100g HB-80 and 20g epoxy resin E-44 were dehydrated for 1.5 hours at 105℃ and 0.05MPa under stirring at 325rpm until the moisture content was below 0.05wt%. Nitrogen gas was then added to depressurize and the temperature was lowered to 50℃. 4.6g 1,6-hexanediamine was then added and the mixture was stirred at 350rpm for 2 hours. After the reaction was completed, 35g toluene diisocyanate was added and the temperature was raised to 80℃ for another 1.5 hours to obtain a prepolymer with NCO%=10.49%, i.e. component B. Nitrogen gas was then used for protection. (3) Mix the prepared components A and B at a mass ratio of 0.21:1, stir at 350 rpm for 40 seconds using a high-speed mixer, pour into a mold, cure at 80°C, demold after 50 min, and vulcanize at 80°C for 14 h to obtain a low-temperature resistant polyurethane elastomer.

[0026] Example 4: A low-temperature resistant polyurethane elastomer material and its preparation method, the specific steps of which are as follows: (1) Mix 10g DL-2000, 15g DL-1000, 30g 2,4-diamino-3,5-dimethylthiotoluene and 0.053g dibutyltin dilaurate, and dehydrate for 2h at 110℃ and 0.05MPa under stirring at 350rpm until the moisture content is below 0.05wt%. After depressurization and cooling to room temperature, seal and store to obtain the curing agent component, i.e. component A; (2) 100g HB-80 and 45g epoxy resin E-51 were dehydrated for 1.5 hours at 105℃ and 0.05MPa under stirring at 330rpm until the moisture content was below 0.05wt%. Nitrogen gas was then added to depressurize and the temperature was lowered to 50℃. 6.2g ethylenediamine was then added and the mixture was stirred at 350rpm for 2 hours. After the reaction was completed, 138g diphenylmethane diisocyanate was added and the temperature was raised to 80℃ to continue the reaction for 1.5 hours to obtain a prepolymer with NCO%=22.95%, i.e. component B. Nitrogen gas was then used for protection. (3) Mix the prepared components A and B at a mass ratio of 0.33:1, stir at 350 rpm for 40 seconds using a high-speed mixer, pour into a mold, cure at 80°C, demold after 50 min, and vulcanize at 80°C for 14 h to obtain a low-temperature resistant polyurethane elastomer.

[0027] Example 5: A low-temperature resistant polyurethane elastomer material and its preparation method, the specific steps of which are as follows: (1) Mix 35g DL-1000, 50g 2,4-diamino-3,5-dimethylthiotoluene and 0.05g dibutyltin dilaurate, and dehydrate for 2h at 110℃ and 0.05MPa under stirring at 250rpm until the moisture content is below 0.05wt%. After depressurization and cooling to room temperature, seal and store to obtain curing agent component, i.e. component A; (2) 100g HB-80 and 50g epoxy resin E-44 were dehydrated for 1.5 hours at 105℃ and 0.05MPa under stirring at 350rpm until the moisture content was below 0.05wt%. Nitrogen gas was then added to depressurize and the temperature was lowered to 60℃. 6.0g ethylenediamine was then added and the mixture was stirred at 300rpm for 1.5 hours. After the reaction was completed, 95g diphenylmethane diisocyanate was added and the temperature was raised to 80℃ to continue the reaction for 1.5 hours to obtain a prepolymer with NCO%=18.17%, i.e. component B. Nitrogen gas was then used for protection. (3) Mix the prepared components A and B at a mass ratio of 0.15:1, stir at 300 rpm for 35 seconds using a high-speed mixer, pour into a mold, cure at 75°C, demold after 40 min, and vulcanize at 80°C for 10 h to obtain a low-temperature resistant polyurethane elastomer.

[0028] Example 6: A low-temperature resistant polyurethane elastomer material and its preparation method, the specific steps of which are as follows: (1) Mix 30g PTMG-1000, 20g 1,4-butanediol, 10g triethanolamine and 0.09g DY-20, and dehydrate at 120℃ and 0.05MPa under stirring at 320rpm until the moisture content is below 0.05wt%. Then depressurize, cool to room temperature and seal to obtain curing agent component, i.e. component A; (2) 80g DL-1000, 20g DL-2000 and 20g epoxy resin E-20 were dehydrated for 1.5 hours at 105℃ and 0.05MPa under stirring at 350rpm until the moisture content was below 0.05wt%. Nitrogen gas was then added to depressurize and the temperature was lowered to 30℃. 5.8g 1,6-hexanediamine was then added and the mixture was stirred at 350rpm for 1.5 hours. After the reaction was completed, 15g toluene diisocyanate was added and the temperature was raised to 80℃ for another 1.5 hours to obtain a prepolymer with NCO%=4.95%, i.e. component B. Nitrogen gas was then used for protection. (3) Mix the prepared components A and B at a mass ratio of 0.07:1, stir at 350 rpm for 40 seconds using a high-speed mixer, pour into a mold, cure at 80°C, demold after 50 min, and vulcanize at 80°C for 14 h to obtain a low-temperature resistant polyurethane elastomer.

[0029] Example 7: A low-temperature resistant polyurethane elastomer material and its preparation method, the specific steps of which are as follows: (1) Mix 30g PTMG-1000, 20g DL-1000, 19g 1,4-butanediol, 35g triethanolamine and 0.10g stannous octoate, and dehydrate for 1h at 110℃ and 0.05MPa under stirring at 250rpm until the moisture content is below 0.05wt%. After depressurization and cooling to room temperature, seal and store to obtain the curing agent component, i.e. component A; (2) 80g HB-80, 20g DL-2000 and 40g epoxy resin E-20 were dehydrated for 1 hour at 120℃ and 0.05MPa under stirring at 350rpm until the moisture content was below 0.05wt%. Nitrogen gas was then added to depressurize and the temperature was lowered to 30℃. 6.01g ethylenediamine was then added and the mixture was stirred at 350rpm for 1.5h. After the reaction was completed, 35g toluene diisocyanate was added and the temperature was raised to 80℃ for another 1.5h to obtain a prepolymer with NCO%=9.23%, i.e. component B. Nitrogen gas was then used for protection. (3) Mix the prepared components A and B at a mass ratio of 0.05:1, stir at 350 rpm for 40 seconds using a high-speed mixer, pour into a mold, cure at 80°C, demold after 50 min, and vulcanize at 80°C for 14 h to obtain a low-temperature resistant polyurethane elastomer.

[0030] Example 8: A low-temperature resistant polyurethane elastomer material and its preparation method, the specific steps of which are as follows: (1) Mix 50g DL-2000, 60g 1,4-butanediol and 0.3g pentamethyldiethylenetriamine, and dehydrate at 115℃ and 0.05MPa under stirring at 325rpm until the moisture content is below 0.05wt%. After depressurization and cooling to room temperature, seal and store to obtain curing agent component, i.e. component A; (2) 60g HB-80, 40g DL-1000 and 10g epoxy resin E-51 were dehydrated for 1 hour at 120℃ and 0.05MPa under stirring at 350rpm until the moisture content was below 0.05wt%. Nitrogen gas was then added to depressurize and the temperature was lowered to 30℃. 4.55g diethyltoluene diamine was then added and the mixture was stirred at 300rpm for 1.5h. After the reaction was completed, 100g diphenylmethane diisocyanate was added and the temperature was raised to 80℃ and the reaction was continued for 1.5h to obtain a prepolymer with NCO%=15.57, i.e. component B. Nitrogen gas was then used for protection. (3) Mix the prepared components A and B at a mass ratio of 0.26:1, stir at 350 rpm for 20 seconds using a high-speed mixer, pour into a mold, cure at 80°C, demold after 50 min, and vulcanize at 80°C for 14 h to obtain a low-temperature resistant polyurethane elastomer.

[0031] Comparative Example 1: A low-temperature resistant polyurethane elastomer material and its preparation method, the specific steps of which are as follows: (1) Mix 10g DL-2000, 50g diethyltoluene diamine and 0.05g dibutyltin dilaurate, and dehydrate at 110℃ and 0.05MPa for 2h under stirring at 350rpm until the moisture content is below 0.05wt%. After depressurization and cooling to room temperature, seal and store to obtain curing agent component, i.e. component A; (2) 100g of HB-80 was dehydrated at 110℃ and 0.05MPa under stirring at 300rpm for 1.5h until the moisture content was below 0.05wt%. Nitrogen gas was then added to depressurize and the temperature was lowered to 30℃. 50g of diphenylmethane diisocyanate was added and the temperature was raised to 80℃ under stirring at 350rpm for 1.5h to obtain a prepolymer with NCO%=8.87%, i.e. component B. Nitrogen gas was then added for protection and left to use. (3) Mix the prepared components A and B at a mass ratio of 0.12:1, stir at 300 rpm for 35 seconds using a high-speed mixer, pour into a mold, cure at 75°C, demold after 40 min, and vulcanize at 80°C for 10 h to obtain a low-temperature resistant polyurethane elastomer.

[0032] Comparative Example 2: A low-temperature resistant polyurethane elastomer material and its preparation method, the specific steps of which are as follows: (1) Mix 10g DL-2000, 50g diethyltoluene diamine and 0.05g dibutyltin dilaurate, and dehydrate for 2h at 110℃ and 0.05MPa under stirring at 300rpm until the moisture content is below 0.05wt%. After depressurization and cooling to room temperature, seal and store to obtain the curing agent component, i.e. component A; (2) 100g of HB-80 and 25g of E-20 were dehydrated at 110℃ and 0.05MPa under stirring at 350rpm for 1.5h until the moisture content was below 0.05wt%. Nitrogen gas was then used for pressure relief. 50g of diphenylmethane diisocyanate was added under N2 atmosphere, and the temperature was raised to 80℃ for 1.5h to obtain a prepolymer with NCO%=7.61%, i.e., component B. Nitrogen gas was then used for pressure relief. (3) Mix the prepared components A and B at a mass ratio of 0.13:1, stir at 300 rpm for 35 seconds using a high-speed mixer, pour into a mold, cure at 75°C, demold after 40 min, and vulcanize at 80°C for 10 h to obtain a low-temperature resistant polyurethane elastomer.

[0033] Comparative Example 3: A low-temperature resistant polyurethane elastomer material and its preparation method, the specific steps of which are as follows: (1) Mix 10g DL-1000, 50g 2,4-diamino-3,5-dimethylthiotoluene and 0.05g dibutyltin dilaurate, and dehydrate for 2h at 110℃ and 0.05MPa under stirring at 300rpm until the moisture content is below 0.05wt%. After depressurization and cooling to room temperature, seal and store to obtain the curing agent component, i.e. component A; (2) 100g of EP-330N and 50g of epoxy resin E-44 were dehydrated for 1.5h at 105℃ and 0.05MPa under stirring at 325rpm until the moisture content was below 0.05wt%. Nitrogen gas was then added to depressurize and the temperature was lowered to 60℃. 6.0g of ethylenediamine was then added and the mixture was stirred at 300rpm for 1.5h. After the reaction was completed, 95g of diphenylmethane diisocyanate was added and the temperature was raised to 80℃ for another 1.5h to obtain a prepolymer with NCO%=8.36%, i.e. component B. Nitrogen gas was then used for protection. (3) Mix the prepared components A and B at a mass ratio of 0.22:1, stir at 300 rpm for 35 seconds using a high-speed mixer, pour into a mold, cure at 75°C, demold after 40 min, and vulcanize at 80°C for 10 h to obtain a low-temperature resistant polyurethane elastomer.

[0034] Performance testing The polyurethane elastomer materials prepared in Examples 1-5 and Comparative Examples 1-3 were subjected to tensile property and glass transition temperature tests. The tensile property tests were conducted according to the method described in GB / T 528-2009, and the glass transition temperature tests were conducted according to the method described in GB / T 29611-2023.

[0035] The relevant detection index results for the example are as follows: Table 1. Main properties of polyurethane elastomer materials prepared in Examples 1-5 and Comparative Examples 1-3

[0036] As shown in the table above, in Comparative Example 1, the amount of crosslinking agent in component A was relatively high, resulting in an overly dense and rigid network structure in the final polymer, which in turn reduced tensile strength and elongation at break. Component B, which does not contain epoxy resin or the organic amine compounds that react with it, showed a significant decrease in tensile strength and elongation at break. This indicates that the present invention, by mixing polyether polyol and epoxy resin as soft segments, can effectively improve the mechanical properties of the material.

[0037] In Comparative Example 2, no organic amine was used as a ring-opening agent for epoxy resin in component B. Epoxy resin was simply mixed into component B. The resulting Tg values ​​were two, indicating significant phase separation in the material, which also had a certain impact on the final mechanical properties.

[0038] In Comparative Example 3, replacing the polyether polyol with excellent low-temperature performance with the highly reactive polyether polyol EP-330N significantly reduced the surface drying time of the material, but also significantly decreased its low-temperature performance. This invention utilizes both the excellent low-temperature properties of polyether polyol and the superior mechanical properties of epoxy resin to improve the overall performance of polyurethane. The resulting polyurethane elastic exhibits excellent mechanical properties, with a Tg reaching -80 to -50℃, demonstrating excellent low-temperature resistance.

[0039] The differences in mechanical properties in Examples 1-8 are mainly determined by the different hard segment contents of the system. In this invention, the soft segments of the polyurethane elastomer material are mainly composed of polyols and epoxy resins, while the hard segments are mainly composed of polyisocyanates, benzene rings present in some polyols, and aromatic amines. As the NCO value of the prepolymer increases and the hard segment content of the polyisocyanate increases, the mechanical properties of the material also improve significantly.

[0040] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. The description of the above embodiments can help understand the principles and methods of the present invention. However, the above embodiments are not unique and should not be construed as limiting the present invention. At the same time, those skilled in the art can make flexible changes to the specific implementation methods and application scope based on the principles and methods of the present invention.

Claims

1. A low-temperature resistant polyurethane elastomer material, characterized in that, The polyurethane elastomer material is composed of component A and component B, and the mass ratio of component A to component B is 0.02 to 1:

1. The A component is a curing agent component, which is formed by physically mixing polyol 1, chain extender and crosslinker and organometallic catalyst, with a mass ratio of 100:0 to 200:0.01 to 1.

0. Component B is a prepolymer component, obtained by reacting polyether polyol 2, epoxy resin, organic amine and polyisocyanate, with a mass ratio of 100:8~55:1.5~10:10~150.

2. The low-temperature resistant polyurethane elastomer material according to claim 1, characterized in that, The mass ratio of polyol 1, chain extender, crosslinking agent, and organometallic catalyst in component A is 100:30-150:0.1-0.6; the mass ratio of polyether polyol 2, epoxy resin, organic amine, and polyisocyanate in component B is 100:10-50:3.5-8.5:20-140.

3. The low-temperature resistant polyurethane elastomer material according to claim 2, characterized in that, The composition of component A, by mass parts, is as follows: Polyol 1 100 parts, 85.71 parts of chain extender / crosslinker, 0.15 parts catalyst; The composition of component B, in parts by mass, is as follows: Polyether polyol 2 100 parts, 45 parts epoxy resin Organic amines: 6.2 parts 138 parts of polyisocyanate.

4. The low-temperature resistant polyurethane elastomer material according to any one of claims 1-3, characterized in that, The polyol 1 is one or a combination of polyether DL-1000, 1,4-butanediol, polyether DL-2000, and PTMG-1000; the chain extender / crosslinker is one or more of 3,3'-dichloro-4,4'-diaminodiphenylmethane, triethanolamine, diethyltoluenediamine, 2,4-diamino-3,5-dimethylthiotoluene, and trimethylolpropane; and the catalyst is one or a combination of organobismuth, organotin, organozinc, organolead, and organic amines.

5. The low-temperature resistant polyurethane elastomer material according to any one of claims 1-3, characterized in that, The polyether polyol 2 is one or a combination of polyether DL-2000, polyether DL-1000, polyether 330N, PTMG-1000, PPG-1000, and HB-80; the epoxy resin is one of E-51, E-20, E-44, and E-68; the organic amine is one of 1,6-hexanediamine, ethylenediamine, diethyltoluenediamine, and 2,4-diamino-3,5-dimethylthiotoluene; and the polyisocyanate is one of toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and polymethylene polyphenyl isocyanate.

6. The low-temperature resistant polyurethane elastomer material according to claim 5, characterized in that, The polyether polyol 2 is two or more combinations of polyether DL-2000, polyether DL-1000 and HB-80; the epoxy resin is one of E-51, E-20 and E-44; the organic amine is one of 1,6-hexanediamine, ethylenediamine, and 2,4-diamino-3,5-dimethylthiotoluene; and the polyisocyanate is one of toluene diisocyanate and diphenylmethane diisocyanate.

7. The low-temperature resistant polyurethane elastomer material according to claim 1, characterized in that, The glass transition temperature of the low-temperature resistant polyurethane elastomer material is -80 to -50℃.

8. A method for preparing the low-temperature resistant polyurethane elastomer material according to any one of claims 1-6, characterized in that, The specific steps are as follows: (1) Mix polyol 1, chain extender and catalyst in proportion, and dehydrate at 100-120℃ and vacuum degree of 0.05-0.1MPa for 1-2 hours under stirring at 250-400 rpm until the moisture content is below 0.05wt%. After depressurization and cooling to room temperature, seal and store to obtain curing agent component, i.e. component A. (2) Polyether polyol 2 and epoxy resin are dehydrated for 1 to 2 hours under stirring at 300 to 400 rpm and at 100 to 120°C and vacuum of 0.05 to 0.10 MPa until the moisture content is below 0.05 wt%. Nitrogen gas is then added to depressurize and the temperature is lowered to 30 to 60°C. Then organic amine is added and reacted at 250 to 350 rpm for 1 to 3 hours. After the reaction is complete, polyisocyanate is added and the temperature is raised to 70 to 90°C to continue the reaction for 1.5 to 2.5 hours. The NCO% is controlled within the range of 4.50% to 23.00% to obtain the prepolymer component, i.e. component B, which is protected by nitrogen gas for later use. (3) Mix component A and component B in proportion and stir at 300-1000 rpm for 20-40 seconds using a high-speed mixer. Pour the mixture into a mold and cure it at 80-100℃. Demold it after 20-60 minutes and vulcanize it at 70-90℃ for 8-14 hours to obtain a low-temperature resistant polyurethane elastomer.

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