High-temperature-resistant polyurethane elastomer material and preparation process thereof

Abstract

The invention relates to the technical field of polyurethane elastomers, and discloses a high-temperature-resistant polyurethane elastomer material and a preparation process thereof, 2, 4, 6-tri-(nitronaphthalene-phenyl)-[1, 3, 5] triazine obtained by reaction of 2, 4, 6-tri-(4-bromophenyl)-[1, 3, 5] triazine and 4-nitro-1-naphthol has excellent heat resistance; the aromatic naphthalene ring structure has a rigid structure, the molecular chain of the aromatic naphthalene ring structure is highly regular, and the polyurethane elastomer synthesized by the aromatic naphthalene ring structure has excellent dynamic performance; 2, 4, 6-tri-(aminonaphthalene-phenyl)-[1, 3, 5] triazine after reduction is utilized to prepare a chain extender containing diamine, and the chain extender and isocyanate generate carbamido, so that the tensile strength of the polyurethane elastomer is improved; through the synergistic effect of triazine, naphthalene ring and hydrogen bond, the prepared polyurethane elastomer is excellent in mechanical property and obvious in high temperature resistance advantage.

Description

[0001] This application is a divisional application of application filed on October 10, 2025, with application number 202511440480.8 and invention title "A high-temperature resistant polyurethane elastomer material and preparation process". Technical Field

[0002] This invention relates to the field of polyurethane elastomer technology, specifically to a high-temperature resistant polyurethane elastomer material and its preparation process. Background Technology

[0003] Polyurethane elastomers are a special material with properties between plastics and rubber. They possess high strength, wear resistance, and tear resistance, and have achieved relatively ideal results in various fields. However, due to their low thermal decomposition temperature and poor heat resistance, especially at high temperatures where their mechanical properties are poorly retained, their application range is greatly limited. As people's requirements for material performance become increasingly stringent, many experts and scholars at home and abroad have conducted in-depth research on how to improve the heat resistance of polyurethane elastomers.

[0004] The main chain of polyurethane elastomers is a block polymer composed of alternating flexible soft segments and rigid hard segments. The soft segments, which provide elastic toughness, are composed of polyols, while the hard segments, which provide hardness modulus, are composed of isocyanates and chain extenders. Invention patent CN104448197B discloses a method for synthesizing heat-resistant polyurethane elastomers, which are prepared by reacting polyester polyols, diisocyanates, and MOCA or butanediol as chain extenders. The resulting elastomers exhibit high performance retention at higher temperatures and are suitable for environments with high ambient temperatures. However, the polyurethane elastomers contain a high content of soft segments, resulting in poor mechanical properties. This invention modifies the chain extenders in polyurethane elastomers, utilizing the high thermal decomposition temperature of triazine structures to improve the heat resistance of polyurethane materials and the highly regular molecular structure of naphthalene rings to improve the mechanical properties of polyurethane materials. The combination of these two factors causes the prepared polyurethane elastomer to crosslink into a network structure, increasing its high-temperature resistance and mechanical strength while maintaining rubber-like elastic toughness. Summary of the Invention

[0005] The technical problem solved by this invention is to provide a high-temperature resistant polyurethane elastomer material and its preparation process, thereby solving the problem of poor heat resistance of polyurethane elastomer materials.

[0006] The technical solution of this invention is: A high-temperature resistant polyurethane elastomer material and its preparation process, wherein the preparation process is carried out according to the following steps: Step S1: Add 2,4,6-tris-(4-bromophenyl)-[1,3,5]triazine and N'N-dimethylformamide to a reaction flask equipped with a condenser and thermometer. Stir until homogeneous, then add 4-nitro-1-naphthol and potassium carbonate. After the reaction is complete, cool and filter. Add methanol to the filtrate to precipitate, filter, wash with deionized water and methanol, and dry to obtain 2,4,6-tris-(nitronaphthyl-phenyl)-[1,3,5]triazine. The preparation reaction formula is as follows:

[0007] Step S2: Add zinc powder and 2,4,6-tris-(nitronaphthyl-phenyl)-[1,3,5]triazine sequentially to a solvent of ethanol and deionized water, stir until homogeneous, and then add 27% hydrochloric acid dropwise at 0-10℃. After the reaction is complete, filter the solution, extract the filtrate with chloroform, concentrate and dry the organic phase, and wash with acetone to obtain 2,4,6-tris-(aminonaphthyl-phenyl)-[1,3,5]triazine. The preparation reaction formula is as follows:

[0008] Step S3: Add 100 parts by weight of polycaprolactone polyol to the reaction flask, stir under a nitrogen atmosphere, and then add 40-55 parts of 4,4-diphenylmethane diisocyanate. After the reaction is completed, degas under vacuum for 30-40 minutes to obtain the terminal isocyanate polyurethane prepolymer.

[0009] Step S4: Dissolve 2,4,6-tris-(aminonaphthalene-phenyl)-[1,3,5]triazine in tetrahydrofuran, add it to the isocyanate-terminated polyurethane prepolymer, stir for 10-20 min, degas under vacuum, pour into a preheated mold coated with a release agent, and vulcanize at 100-120℃ for 12-24 h to obtain a high-temperature resistant polyurethane elastomer material.

[0010] Furthermore, in step S1, the amounts of 4-nitro-1-naphthol and potassium carbonate are 110-150% and 35-42% of the amounts of 2,4,6-tris-(4-bromophenyl)-[1,3,5]triazine, respectively.

[0011] Furthermore, in step S1, the reaction temperature is 140-160℃ and the reaction time is 16-24h.

[0012] Furthermore, in step S2, the amounts of zinc powder and 27% hydrochloric acid used are 70%-110% and 40-70% of 2,4,6-tris-(nitronaphthyl-phenyl)-[1,3,5]triazine, respectively.

[0013] Furthermore, in step S2, the reaction temperature is 50-70℃ and the reaction time is 3-8h.

[0014] Furthermore, in step S3, the reaction temperature is 75-85℃ and the reaction time is 2-4h.

[0015] Furthermore, in step S4, the amount of 2,4,6-tris-(aminonaphthalene-phenyl)-[1,3,5]triazine used is 36-63% of the amount of the terminal isocyanate polyurethane prepolymer.

[0016] The beneficial technical effects of this invention are: This invention first reacts 2,4,6-tris-(4-bromophenyl)-[1,3,5]triazine with 4-nitro-1-naphthol to obtain 2,4,6-tris-(nitronaphthyl-phenyl)-[1,3,5]triazine. Then, the nitro group is reduced under the action of zinc powder and hydrochloric acid to obtain 2,4,6-tris-(aminonaphthyl-phenyl)-[1,3,5]triazine. Next, polycaprolactone polyol and 4,4-diphenylmethane diisocyanate are vacuum degassed to obtain a terminal isocyanate polyurethane prepolymer. Finally, 2,4,6-tris-(aminonaphthyl-phenyl)-[1,3,5]triazine is used as a chain extender, and after casting and vulcanization, a high-temperature resistant polyurethane elastomer material is obtained.

[0017] 2,4,6-Tris-(4-bromophenyl)-[1,3,5]triazine, obtained by reacting 2,4,6-tris-(nitronaphthyl-phenyl)-[1,3,5]triazine with 4-nitro-1-naphthol, contains both triazine and naphthalene rings. The triazine ring structure is stable and does not easily decompose at high temperatures, exhibiting excellent heat resistance. When introduced into polyurethane elastomers, it increases the heat resistance of the polyurethane material. The aromatic naphthalene ring structure has a rigid symmetrical structure and highly regular molecular chains. Polyurethane elastomers synthesized from it exhibit excellent dynamic properties, combining good elasticity and high-temperature resistance. Advantages: 2,4,6-tris-(nitronaphthyl-phenyl)-[1,3,5]triazine is reduced to 2,4,6-tris-(aminonaphthyl-phenyl)-[1,3,5]triazine to prepare a chain extender containing diamine. This chain extender can form a urea group with isocyanate, which contains two active hydrogens to form hydrogen bonds. The hydrogen bond has a high relative density, strong intermolecular interaction, and high thermal decomposition temperature. Therefore, the effect of hydrogen bonds improves the tensile strength of polyurethane elastomers. The synergistic effect of triazine, naphthalene ring and hydrogen bonds makes the prepared polyurethane elastomer not only have excellent mechanical properties, but also have the advantage of high temperature resistance. Detailed Implementation

[0018] The following examples further illustrate the above-described content of the present invention, but it should not be construed as limiting the scope of the subject matter of the present invention to the following examples. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention.

[0019] Example 1 Step S1: Add 50g of 2,4,6-tris-(4-bromophenyl)-[1,3,5]triazine and N'N-dimethylformamide to a reaction flask equipped with a condenser and a thermometer, stir well, add 70g of 4-nitro-1-naphthol and 20g of potassium carbonate, react at 150℃ for 18h, cool and filter, add methanol to the filtrate to precipitate, filter, wash with deionized water and methanol, and dry to obtain 2,4,6-tris-(nitronaphthyl-phenyl)-[1,3,5]triazine.

[0020] Step S2: Add 20g of zinc powder and 25g of 2,4,6-tris-(nitronaphthyl-phenyl)-[1,3,5]triazine to a solvent of ethanol and deionized water, stir well, add 15g of 27% hydrochloric acid dropwise at 0℃, react at 70℃ for 4h, filter, extract the filtrate with chloroform, concentrate and dry the organic phase, wash with acetone to obtain 2,4,6-tris-(aminonaphthyl-phenyl)-[1,3,5]triazine.

[0021] Step S3: Add 60g of polycaprolactone polyol to the reaction flask, stir under a nitrogen atmosphere, add 30g of 4,4-diphenylmethane diisocyanate, react at 80℃ for 4h, and then degas under vacuum for 30min to obtain the terminal isocyanate polyurethane prepolymer.

[0022] Step S4: Dissolve 36g of 2,4,6-tris-(aminonaphthalene-phenyl)-[1,3,5]triazine in tetrahydrofuran, add it to 100g of terminal isocyanate polyurethane prepolymer, stir for 20min, degas under vacuum, pour into a preheated mold coated with a release agent, and vulcanize at 110℃ for 16h to obtain a high-temperature resistant polyurethane elastomer material.

[0023] Example 2 Step S1: Add 30g of 2,4,6-tris-(4-bromophenyl)-[1,3,5]triazine and N'N-dimethylformamide to a reaction flask equipped with a condenser and thermometer, stir well, add 40g of 4-nitro-1-naphthol and 11g of potassium carbonate, react at 140℃ for 24h, cool and filter, add methanol to the filtrate to precipitate, filter, wash with deionized water and methanol, and dry to obtain 2,4,6-tris-(nitronaphthyl-phenyl)-[1,3,5]triazine.

[0024] Step S2: Add 24g of zinc powder and 40g of 2,4,6-tris-(nitronaphthyl-phenyl)-[1,3,5]triazine to the solvents of ethanol and deionized water, stir well, add 20g of 27% hydrochloric acid dropwise at 5°C, react at 70°C for 5h, filter, extract the filtrate with chloroform, concentrate and dry the organic phase, wash with acetone to obtain 2,4,6-tris-(aminonaphthyl-phenyl)-[1,3,5]triazine.

[0025] Step S3: Add 200g of polycaprolactone polyol to the reaction flask, stir under a nitrogen atmosphere, add 90g of 4,4-diphenylmethane diisocyanate, react at 75℃ for 4h, and then degas under vacuum for 40min to obtain the terminal isocyanate polyurethane prepolymer.

[0026] Step S4: Dissolve 43g of 2,4,6-tris-(aminonaphthalene-phenyl)-[1,3,5]triazine in tetrahydrofuran, add it to 100g of terminal isocyanate polyurethane prepolymer, stir for 20min, degas under vacuum, pour into a preheated mold coated with a release agent, and vulcanize at 120℃ for 14h to obtain a high-temperature resistant polyurethane elastomer material.

[0027] Example 3 Step S1: Add 100g of 2,4,6-tris-(4-bromophenyl)-[1,3,5]triazine and N'N-dimethylformamide to a reaction flask equipped with a condenser and thermometer, stir well, add 110g of 4-nitro-1-naphthol and 42g of potassium carbonate, react at 160℃ for 22h, cool and filter, add methanol to the filtrate to precipitate, filter, wash with deionized water and methanol, and dry to obtain 2,4,6-tris-(nitronaphthyl-phenyl)-[1,3,5]triazine.

[0028] Step S2: Add 96g of zinc powder and 120g of 2,4,6-tris-(nitronaphthyl-phenyl)-[1,3,5]triazine sequentially to the solvents of ethanol and deionized water, stir well, add 72g of 27% hydrochloric acid dropwise at 10℃, react at 50℃ for 6h, filter, extract the filtrate with chloroform, concentrate and dry the organic phase, wash with acetone to obtain 2,4,6-tris-(aminonaphthyl-phenyl)-[1,3,5]triazine.

[0029] Step S3: Add 150g of polycaprolactone polyol to the reaction flask, stir under a nitrogen atmosphere, add 75g of 4,4-diphenylmethane diisocyanate, react at 85℃ for 4h, and then degas under vacuum for 35min to obtain the terminal isocyanate polyurethane prepolymer.

[0030] Step S4: Dissolve 50g of 2,4,6-tris-(aminonaphthalene-phenyl)-[1,3,5]triazine in tetrahydrofuran, add it to 100g of terminal isocyanate polyurethane prepolymer, stir for 15min, degas under vacuum, pour into a preheated mold coated with a release agent, and vulcanize at 100℃ for 20h to obtain a high-temperature resistant polyurethane elastomer material.

[0031] Example 4 Step S1: Add 40g of 2,4,6-tris-(4-bromophenyl)-[1,3,5]triazine and N'N-dimethylformamide to a reaction flask equipped with a condenser and a thermometer, stir well, add 60g of 4-nitro-1-naphthol and 16g of potassium carbonate, react at 150℃ for 24h, cool and filter, add methanol to the filtrate to precipitate, filter, wash with deionized water and methanol, and dry to obtain 2,4,6-tris-(nitronaphthyl-phenyl)-[1,3,5]triazine.

[0032] Step S2: Add 110g of zinc powder and 100g of 2,4,6-tris-(nitronaphthyl-phenyl)-[1,3,5]triazine to the solvents of ethanol and deionized water, stir well, add 65g of 27% hydrochloric acid dropwise at 0℃, react at 70℃ for 8h, filter, extract the filtrate with chloroform, concentrate and dry the organic phase, wash with acetone to obtain 2,4,6-tris-(aminonaphthyl-phenyl)-[1,3,5]triazine.

[0033] Step S3: Add 50g of polycaprolactone polyol to the reaction flask, stir under a nitrogen atmosphere, add 26g of 4,4-diphenylmethane diisocyanate, react at 80℃ for 3h, and then degas under vacuum for 40min to obtain the terminal isocyanate polyurethane prepolymer.

[0034] Step S4: Dissolve 58g of 2,4,6-tris-(aminonaphthalene-phenyl)-[1,3,5]triazine in tetrahydrofuran, add it to 100g of terminal isocyanate polyurethane prepolymer, stir for 15min, degas under vacuum, pour into a preheated mold coated with a release agent, and vulcanize at 120℃ for 18h to obtain a high-temperature resistant polyurethane elastomer material.

[0035] Example 5 Step S1: Add 10g of 2,4,6-tris-(4-bromophenyl)-[1,3,5]triazine and N'N-dimethylformamide to a reaction flask equipped with a condenser and a thermometer, stir well, add 14g of 4-nitro-1-naphthol and 4g of potassium carbonate, react at 150℃ for 16h, cool and filter, add methanol to the filtrate to precipitate, filter, wash with deionized water and methanol, and dry to obtain 2,4,6-tris-(nitronaphthyl-phenyl)-[1,3,5]triazine.

[0036] Step S2: Add 55g of zinc powder and 60g of 2,4,6-tris-(nitronaphthyl-phenyl)-[1,3,5]triazine to the solvents of ethanol and deionized water, stir well, add 28g of 27% hydrochloric acid dropwise at 5°C, react at 60°C for 5h, filter, extract the filtrate with chloroform, concentrate and dry the organic phase, wash with acetone to obtain 2,4,6-tris-(aminonaphthyl-phenyl)-[1,3,5]triazine.

[0037] Step S3: Add 90g of polycaprolactone polyol to the reaction flask, stir under a nitrogen atmosphere, add 36g of 4,4-diphenylmethane diisocyanate, react at 75℃ for 4h, and then degas under vacuum for 40min to obtain the terminal isocyanate polyurethane prepolymer.

[0038] Step S4: Dissolve 63g of 2,4,6-tris-(aminonaphthalene-phenyl)-[1,3,5]triazine in tetrahydrofuran, add it to 100g of terminal isocyanate polyurethane prepolymer, stir for 20min, degas under vacuum, pour into a preheated mold coated with a release agent, and vulcanize at 120℃ for 18h to obtain a high-temperature resistant polyurethane elastomer material.

[0039] Comparative Example 1 Step S1: Add 100g of polycaprolactone polyol to the reaction flask, stir under a nitrogen atmosphere, add 55g of 4,4-diphenylmethane diisocyanate, react at 85℃ for 4h, and then degas under vacuum for 40min to obtain the terminal isocyanate polyurethane prepolymer.

[0040] Step S2: Dissolve 63g of ethylenediamine in tetrahydrofuran, add it to 100g of terminal isocyanate polyurethane prepolymer, stir for 20min, degas under vacuum, pour into a preheated mold coated with a release agent, and vulcanize at 120℃ for 20h to obtain a high-temperature resistant polyurethane elastomer material.

[0041] Thermogravimetric analysis: Thermogravimetric analysis was used for testing under a nitrogen atmosphere, with a heating rate of 10℃ / min, a sample volume of 20-30mg, and a temperature range of 50-600℃.

[0042] T 50% Temperature at which weight loss reaches 50%, T max : Maximum weightlessness temperature.

[0043]

[0044] As shown in the table above, the heat resistance of polyurethane elastomers increases with the increase of triazine and naphthalene ring content. This is due to the special structure of triazine and naphthalene rings. Triazine rings have a high decomposition temperature, and aromatic naphthalene rings have large steric hindrance and highly regular molecular chains. The combination of the two can hinder the relative movement of molecular chain segments during heating, forming a very stable and rigid system. This allows the polymer to absorb a large amount of heat energy without breaking the main chain, resulting in excellent thermal stability. Compared with the polyurethane elastomer in Comparative Example 1 that does not contain triazine and naphthalene rings, the 50% weight loss temperature increased by 39°C, and the maximum weight loss temperature increased by 40°C. Therefore, the introduction of triazine and naphthalene rings improves the thermal stability and enhances the high-temperature resistance of the elastomer.

[0045] Mechanical property testing: The tensile properties of the elastomer were tested using a universal testing machine. The specimen was prepared with a size of 20 mm × 10 mm × 10 mm and the tensile rate was 200 mm / min.

[0046] Hardness test: Use a hardness tester.

[0047]

[0048] As shown in the table above, when other components are the same, the mechanical properties of the polyurethane elastomer with 2,4,6-tris-(aminonaphthalene-phenyl)-[1,3,5]triazine as the chain extender are better than those of the elastomer with ethylenediamine as the chain extender in Comparative Example 1. With the increase of triazine and naphthalene ring content, the strength and hardness of the polyurethane elastomer increase, but the elongation at break decreases. This is because the polyurethane elastomer containing triazine and naphthalene ring has a relatively regular structure and high crystallinity. With the increase of hard segment content, the number of physical crosslinking points in the molecular chain segments increases, which makes the fracture strength and hardness increase with the increase of hard segment content. At the same time, the increase of hard segment content makes the molecular chains of soft segment movement shorter, which leads to the obstruction of molecular movement and reduces the elongation at break of the material. However, the whole system still has high elasticity and maintains the characteristics of an elastomer.

[0049] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A preparation process for a high-temperature resistant polyurethane elastomer material, characterized in that: The preparation process is carried out according to the following steps: Step S1: Add 2,4,6-tris-(4-bromophenyl)-[1,3,5]triazine and N'N-dimethylformamide to a reaction flask equipped with a condenser and a thermometer, stir until homogeneous, add 4-nitro-1-naphthol and potassium carbonate, cool and filter after the reaction is complete, add methanol to the filtrate to precipitate, filter, wash with deionized water and methanol, and dry to obtain 2,4,6-tris-(nitronaphthyl-phenyl)-[1,3,5]triazine; Step S2: Add zinc powder and 2,4,6-tris-(nitronaphthyl-phenyl)-[1,3,5]triazine sequentially to the solvents of ethanol and deionized water, stir well, add 27% hydrochloric acid dropwise at 0-10℃, filter after the reaction is complete, extract the filtrate with chloroform, concentrate and dry the organic phase, wash with acetone to obtain 2,4,6-tris-(aminonaphthyl-phenyl)-[1,3,5]triazine; Step S3: Add 100 parts by weight of polycaprolactone polyol to the reaction flask, stir under a nitrogen atmosphere, then add 40-55 parts of 4,4-diphenylmethane diisocyanate. After the reaction is completed, degas under vacuum for 30-40 minutes to obtain the isocyanate-terminated polyurethane prepolymer. Step S4: Dissolve 2,4,6-tris-(aminonaphthalene-phenyl)-[1,3,5]triazine in tetrahydrofuran, add it to the isocyanate-terminated polyurethane prepolymer, stir for 10-20 min, degas under vacuum, pour into a preheated mold coated with a release agent, and vulcanize at 100-120℃ for 12-24 h to obtain a high-temperature resistant polyurethane elastomer material; In step S1, the amounts of 4-nitro-1-naphthol and potassium carbonate are 110-150% and 35-42% of the amounts of 2,4,6-tris-(4-bromophenyl)-[1,3,5]triazine, respectively. In step S2, the amounts of zinc powder and 27% hydrochloric acid used are 70%-110% and 40-70% of 2,4,6-tris-(nitronaphthyl-phenyl)-[1,3,5]triazine, respectively.

2. The preparation process of the high-temperature resistant polyurethane elastomer material according to claim 1, characterized in that: In step S1, the reaction temperature is 140-160℃ and the reaction time is 16-24h.

3. The preparation process of the high-temperature resistant polyurethane elastomer material according to claim 1, characterized in that: In step S2, the reaction temperature is 50-70℃ and the reaction time is 3-8h.

4. The preparation process of the high-temperature resistant polyurethane elastomer material according to claim 1, characterized in that: In step S3, the reaction temperature is 75-85℃ and the reaction time is 2-4h.

5. The preparation process of the high-temperature resistant polyurethane elastomer material according to claim 1, characterized in that: In step S4, the amount of 2,4,6-tris-(aminonaphthalene-phenyl)-[1,3,5]triazine used is 36-63% of the amount of the terminal isocyanate polyurethane prepolymer.

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