Bio-based polyurethane elastic interface material and preparation method thereof

Abstract

The invention relates to a bio-based polyurethane elastic interface material and a preparation method thereof, the interface material is prepared by taking bio-based raw materials such as bio-based polyol and bio-based diisocyanate as main components, performing condensation polymerization, then adding a nano reinforced flexibilizer, a polyurethane-grade filler, black paste and a functional auxiliary agent, and performing vacuum stirring and mixing, the product has higher tensile strength, elongation at break, peel strength and high and low temperature resistance, reduces the dependence on fossil resources, is low-carbon and environment-friendly, meets the dual-carbon target and environmental protection requirements, and is particularly suitable for bonding polyurethane mute cotton and the inner wall of a tire in a mute tire.

Description

Technical Field

[0001] This invention relates to the field of polymer interface materials technology, specifically to a bio-based polyurethane elastic interface material and its preparation method for bonding sound-absorbing cotton to the inner wall of automobile tires. This interface material is particularly suitable for the manufacture of quiet tires for new energy vehicles, used to firmly bond polyurethane sound-absorbing cotton to the inner wall of the tire to achieve noise reduction, while also possessing environmentally friendly, high and low temperature resistance, and high bonding strength characteristics. Background Technology

[0002] With the rapid development of the automotive industry, consumers' demands for vehicle comfort are constantly increasing, especially for new energy vehicles, which have higher and higher requirements for noise reduction and comfort. Tire noise, as one of the important factors affecting comfort, is receiving increasing attention. Silent tires reduce cavity resonance and noise by attaching sound-absorbing materials such as polyurethane sound-absorbing cotton to the inner wall, which can significantly reduce in-vehicle noise and improve driving quietness. However, traditional silent tire interface materials have the following problems: (1) Poor environmental performance: Toxic solvents such as toluene and benzene are used in the synthesis process, which have VOC pollution problems and are corrosive to chlorinated butyl rubber, which does not meet environmental protection requirements; (2) Low bio-based content: Traditional petroleum-based interface materials rely on non-renewable resources, which are unsustainable and difficult to meet the needs of sustainable development, and do not meet the "dual carbon" target requirements; (3) Insufficient dynamic performance: The peel strength is not enough, and the silent cotton is easy to fall off during the dynamic use of the tire. The silent cotton bears complex stress during driving, which is easy to cause displacement, delamination problems, sponge peeling, and risk of falling off, which can lead to safety hazards; (4) Insufficient weather resistance: Under extreme climatic conditions, especially in the alternating high and low temperature environment, the bonding performance drops significantly, causing the silent cotton to fall off. Therefore, there is an urgent need for a high-adhesion, high-elasticity, fast-curing, and environmentally friendly interface material in the field of automotive tire noise reduction. This material can build a strong and durable connection between the tire and the noise reduction material. Especially under high-speed driving and complex road conditions, the tire is subjected to huge pressure and vibration, requiring the interface material to have high adhesion to ensure that the noise reduction material is always firmly attached and that the vehicle noise is significantly reduced, providing a solid guarantee for the noise reduction effect.

[0003] In recent years, bio-based polyurethane interface materials have gradually gained popularity due to their environmental friendliness and renewability. For example, bio-based polyols prepared from biomass such as vegetable oils (soybean oil, castor oil, palm oil, etc.) and sugars (glucose, sucrose) have become a focus in the polyurethane materials field as a sustainable alternative to traditional petroleum-based polyols, thanks to their unique performance and environmental advantages. The carbon emissions of their production process are significantly lower than those of petroleum-based processes, making them environmentally friendly and sustainable, and meeting the "dual carbon" target requirements. Bio-based isocyanates, such as 1,5-pentanediisocyanate (PDI), are mainly synthesized from renewable biomass resources such as corn stalks. Their synthesis process is green, low-carbon, environmentally friendly, and has unique advantages for sustainable development, meeting the environmental requirements of industrial upgrading and green health. Bio-based polyurethane interface materials prepared using bio-based polyols and bio-based isocyanates possess excellent adhesive strength, good tensile strength and elongation at break, excellent mechanical properties, outstanding chemical stability, and excellent light resistance, low-temperature resistance, weather resistance, and oil resistance. Therefore, developing a bio-based polyurethane elastic interface material that combines high performance, environmental friendliness, and good weather resistance is of great significance to the development of silent tire technology. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a bio-based polyurethane elastic interface material for tire sound-absorbing cotton and its preparation method. This interface material is mainly based on bio-based raw materials, is environmentally friendly, and after curing, it exhibits high tensile strength, elongation at break, peel strength, good adhesion, and resistance to high and low temperatures. This ensures that the sound-absorbing cotton is not easily displaced and remains firmly attached, making it particularly suitable for the manufacture of quiet tires.

[0005] To achieve the above objectives, the technical solution adopted by the present invention includes the following steps: 1. Bio-based polyurethane elastic interface material, by weight, comprises the following components: 60-80 parts of bio-based polyurethane prepolymer, 6-20 parts of polyurethane-grade functional filler, 5-10 parts of black paste, 2-5 parts of dehydrating agent, 1-2 parts of thixotropic agent, 0.5-10 parts of viscosity modifier, 0.3-1 part of coupling agent, 0.5-3 parts of nano-reinforcing agent, and 3-8 parts of flame retardant.

[0006] 2. According to a preferred embodiment of the present invention, the bio-based polyurethane elastic interface material described in step 1, wherein the nano-reinforcing agent is a multi-walled carbon nanotube. Carbon nanotubes have good mechanical properties and impact resistance, and as a functional filler, they can enhance the mechanical properties of the material. Furthermore, the silane-coupled carbon nanotubes have coupling groups and can be copolymerized in situ into polyurethane molecular chains with end groups. Its performance indicators are: purity ≥97%, inner diameter 3-5 nm, length 10-50 μm, and specific surface area ≥200 m² / g.

[0007] 3. According to a preferred embodiment of the present invention, the bio-based polyurethane elastic interface material described in step 1, wherein the viscosity modifier is a low molecular weight methoxysilane-terminated polyether, which is a functional polymer with polyether as the main chain and methoxysilane groups grafted onto both ends by chemical bonds, and has a molecular weight of 200-400. In addition to regulating viscosity, the low molecular weight methoxysilane-terminated polyether has the characteristics of low VOC, resistance to UV irradiation, resistance to high and low temperatures, high elongation, room temperature humidity curing to form a cross-linked structure, and good curing characteristics. It can adapt to dynamic displacement and avoid adhesion failure caused by material deformation, and is one of the important components of elastic interface materials.

[0008] 4. According to a preferred embodiment of the present invention, in the bio-based polyurethane elastic interface material described in step 1, the thixotropic agent is one or a combination of two of organobentonite and fumed silica.

[0009] 5. According to a preferred embodiment of the present invention, the bio-based polyurethane elastic interface material described in step 1, wherein the flame retardant is one or a combination of several of dimethyl methyl phosphate (DMMP), triethyl phosphate, tris(2-chloropropyl) phosphate (TCPP), tris(2-chloroethyl) phosphate (TCEP), and alkyl sulfonate phenyl ester.

[0010] 6. According to a preferred embodiment of the present invention, the bio-based polyurethane elastic interface material described in step 1, wherein the dehydrating agent is one or a combination of two of triethyl orthoformate and oxazolidine derivatives.

[0011] 7. According to a preferred embodiment of the present invention, the bio-based polyurethane elastic interface material described in step 1, wherein the coupling agent is one or a combination of two of the following: γ-methacryloyloxypropyltrimethoxysilane, 3-epoxypropoxypropyltrimethoxysilane (KH-560), 3-epoxypropoxypropyltriethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, and phenyltriethoxysilane.

[0012] 8. According to a preferred embodiment of the present invention, the bio-based polyurethane elastic interface material described in step 1, wherein the polyurethane-grade filler is one or a combination of two of the following: heavy calcium carbonate, light calcium carbonate, talc, and bentonite.

[0013] 9. According to a preferred embodiment of the present invention, the bio-based polyurethane elastic interface material described in step 1, wherein the bio-based polyurethane prepolymer is obtained by polycondensation reaction and, by weight, comprises the following components: 40-70 parts of bio-based polyol, 8-25 parts of bio-based isocyanate, 10-25 parts of reactive adhesive toughening agent, 0.2-4 parts of antioxidant, 0.05-0.35 parts of catalyst, and 0.2-5 parts of chain extender; the NCO content of the bio-based polyurethane prepolymer is 2.0-10.0%, and the viscosity is 5000-30000 mPa·s (25°C).

[0014] 10. According to a preferred embodiment of the present invention, the condensation reaction of the bio-based polyurethane prepolymer in step 9, wherein the bio-based polyol is one or a combination of two of vegetable oil-based polyols and bio-based polyester polyols; the performance indicators of the vegetable oil-based polyol are hydroxyl value 150-450 mgKOH / g, acid value ≤2.0 mgKOH / g, moisture content ≤0.1%, and functionality 2; the performance indicators of the bio-based polyester polyol are hydroxyl value 50-300 mgKOH / g, acid value ≤2.0 mgKOH / g, moisture content ≤0.1%, and functionality 2.

[0015] 11. According to a preferred embodiment of the present invention, the bio-based polyurethane prepolymer condensation reaction in step 9, wherein the bio-based isocyanate is: bio-based 1,5-pentanediisocyanate (PDI), wherein PDI is prepared by bio-fermentation technology of starch sugar obtained from non-grain sources to obtain lysine, and 1,5-pentanediamine is prepared under the catalysis of lysine bio-decarboxylase, and finally PDI is synthesized; PDI is a novel aliphatic isocyanate derived from renewable biomass, which not only has excellent mechanical properties and chemical stability, but also excellent light and weather resistance, and is widely used in many industries such as adhesives, elastomers and high-grade coatings; its low-carbon, environmentally friendly and sustainable characteristics make it an ideal choice for upgrading and replacement, and for green, healthy and environmentally friendly requirements. Its performance indicators are: purity ≥98%, acidity ≤0.01%, moisture ≤0.1%, color (platinum-cobalt color number) ≤30, and non-volatile matter ≤0.1%.

[0016] 12. According to a preferred embodiment of the present invention, in the polycondensation reaction of the bio-based polyurethane prepolymer in step 9, the reactive adhesive toughening agent is hydroxyl-terminated liquid polybutadiene rubber (HTPB). Since its molecular structure contains primary hydroxyl groups, double bonds, and ether bonds, the primary hydroxyl groups form chemical bonds with the bio-based isocyanate, enhancing interfacial adhesion and improving the toughness and tack of the adhesive. The ether bonds are flexible, and the hydroxyl-terminated liquid polybutadiene rubber can quickly wet the substrate being bonded, improve initial tack, impart good flexibility to the adhesive, prevent embrittlement and cracking in low-temperature environments, and ensure that the bonded area remains elastic when used in cold regions. Its performance indicators are: water content ≤0.1%, hydroxyl value 25.0-36.0 mgKOH / g, and viscosity 4~8 Pa·s (25℃).

[0017] 13. According to a preferred embodiment of the present invention, the bio-based polyurethane prepolymer polycondensation reaction in step 9, wherein the antioxidant is one or a combination of two of antioxidant 1010, antioxidant 1098, antioxidant 3052, and antioxidant GS.

[0018] 14. According to a preferred embodiment of the present invention, the bio-based polyurethane prepolymer polycondensation reaction in step 9, wherein the catalyst is one or a combination of two of the following: stannous octoate, dibutyltin dilaurate, triethylenediamine, and dimorpholinodiethyl ether.

[0019] 15. According to a preferred embodiment of the present invention, the polycondensation reaction of the bio-based polyurethane prepolymer in step 9, wherein the chain extender is one or a combination of two of the following: 1,4-butanediol, ethylene glycol, propylene glycol, triethylene glycol diethylene glycol, neopentyl glycol, etc.

[0020] 16. A method for preparing bio-based polyurethane elastic interface materials, comprising the following preparation steps: Bio-based polyurethane prepolymer, polyurethane-grade filler, dehydrating agent, black paste, and nano-reinforcing toughening agent are added to a mixing tank in proportion and stirred under vacuum until fully mixed. After stopping stirring and releasing the vacuum, flame retardant, coupling agent, and viscosity modifier are added to the mixing tank, and stirred under vacuum again until fully mixed to obtain bio-based polyurethane elastic interface material for tire bonding sound insulation cotton.

[0021] Technical effects of the present invention: 1. Using bio-based polyols and bio-based isocyanates as main raw materials, a bio-based prepolymer is obtained through condensation polymerization reaction as the base material, and then fillers, black paste, and functional additives are added to prepare a bio-based polyurethane elastic interface material. Because bio-based raw materials are used, the dependence on fossil resources and environmental pollution are reduced, which meets the needs of green and sustainable supply chains and conforms to the "dual carbon" target and environmental protection requirements.

[0022] 2. The bio-based polyurethane elastic interface material for tire bonding sound-absorbing cotton of the present invention has high tensile strength and elongation at break, with a tensile strength of over 1.6 MPa and an elongation at break of over 500%, which can meet the requirements of high elasticity and high strength. At the same time, because the isocyanate groups in its molecules form stable chemical bonds with materials such as foam cotton and rubber, it has high bonding strength and peel strength to foam cotton and rubber, such as a 180° peel strength of over 6 N / mm. The sound-absorbing cotton is not prone to displacement, ensuring reliability.

[0023] 3. The bio-based polyurethane elastic interface material for tire bonding sound insulation cotton of the present invention has good high and low temperature resistance, such as a high temperature bonding strength retention rate of 92-94% and a low temperature bonding strength retention rate of 95-97%, ensuring that the sound insulation cotton does not fall off in alternating high and low temperature environments, and meeting the needs of tires for long-term use in outdoor high and low temperature environments.

[0024] The specific implementation is as follows: The present invention will be further described below with reference to specific implementation examples, but this is not intended to limit the scope of protection. Furthermore, the experimental methods described in the following implementation examples are conventional methods unless otherwise specified. The present invention will be described in detail below with reference to the embodiments, but it should be noted that these embodiments are not intended to limit the present invention. Equivalent transformations or substitutions in function, method, or structure made by those skilled in the art based on these embodiments are all within the scope of protection of the present invention. Example

[0025] Unless otherwise specified, the reagents and materials used in the examples are commercially available.

[0026] Preparation of bio-based polyurethane prepolymer (I): 1000g of vegetable oil-based polyol (molecular weight: 1050; hydroxyl value: 105.7mgKOH / g; acid value: 1.2mgKOH / g; functionality: 2), 450g of bio-based polyester polyol (molecular weight: 2000; hydroxyl value: 55.2mgKOH / g; acid value: 1.0mgKOH / g; functionality: 2), 300g of hydroxyl-terminated liquid polybutadiene rubber (molecular weight: 2000; hydroxyl value: 26.1mgKOH / g; functionality: 2), and 6g of antioxidant 1010 were added to a 3L reactor. The reactor was evacuated to -0.09MPa, heated to 110℃ for dehydration for 2 hours, and then cooled to 60℃ to obtain a polymer polyol mixture (component A) for later use.

[0027] 256g of bio-based 1,5-pentanediisocyanate (NCO / OH equivalent ratio of 1.3; purity ≥98%) was poured into a 3L reactor. The above-mentioned polymerized polyol mixture (component A) was added to the reactor (3L). After reacting at 70℃ for 3 hours, 3g of stannous octoate was added, and the reaction continued for 0.5 hours. Then, 20g of chain extender triethylene glycol was added, and the reaction was carried out at 60℃ for 2 hours to obtain bio-based polyurethane prepolymer (I). The NCO content was measured to be 4.8%, and the viscosity was 5530 mPa·s (25℃).

[0028] Preparation of bio-based polyurethane prepolymer (II): 1000g of vegetable oil-based polyol (molecular weight: 1050; hydroxyl value: 105.7mgKOH / g; acid value: 1.2mgKOH / g; functionality: 2), 450g of bio-based polyester polyol (molecular weight: 2000; hydroxyl value: 55.2mgKOH / g; acid value: 1.0mgKOH / g; functionality: 2), and 6g of antioxidant 1098 were added to a 3L reactor. The reactor was evacuated to -0.09MPa, heated to 110℃ for dehydration for 2 hours, and then cooled to 60℃ to obtain a polymerized polyol mixture (component B) for later use.

[0029] 256g of bio-based 1,5-pentanediisocyanate (NCO / OH equivalent ratio of 1.3; purity ≥98%) was poured into a 3L reactor. The above-mentioned polymerized polyol mixture (component B) was added to the reactor (3L). After reacting at 70℃ for 3h, 3g of dibutyltin dilaurate and 6g of bismorpholino diethyl ether were added. After reacting for another 0.5h, 20g of chain extender triethylene glycol was added. The reaction was controlled at 60℃ for 2h to obtain bio-based polyurethane prepolymer (II). The NCO content was measured to be 4.5%, and the viscosity was 6260mPa·s (25℃). Example 1:

[0030] Add 300g of bio-based polyurethane prepolymer (I), 30g of triisopropylphenyl phosphate, and 10g of oxazolidine (ALT-201) dehydrating agent to a vacuum mixing tank, apply vacuum, and stir until the materials are evenly mixed. Stop stirring, close the vacuum, and release the vacuum by purging with nitrogen. Add 30g of dehydrated and dried black paste, 3g of multi-walled carbon nanotubes, 50g of polyurethane-grade talc, 4g of γ-methacryloyloxypropyltrimethoxysilane, 5g of fumed silica, and 6g of methoxysilane-terminated polyether to the vacuum mixing tank and stir until evenly mixed under vacuum. Stop stirring, close the vacuum valve, and release the vacuum by purging with nitrogen to obtain the bio-based polyurethane elastic interface material, which is a black, homogeneous, and fine paste. Store in a container for later use. Example 2:

[0031] Add 300g of bio-based polyurethane prepolymer (I), 30g of alkyl sulfonate phenyl ester, and 10g of triethyl orthoformate to a vacuum mixing tank, evacuate the vacuum, and stir until the materials are uniformly mixed. Stop stirring, close the vacuum valve, and release the vacuum by purging with nitrogen. Add 30g of dehydrated and dried black paste, 3g of multi-walled carbon nanotubes, 50g of polyurethane-grade calcium carbonate, 4g of 3-epoxypropoxypropyltrimethoxysilane, 5g of fumed silica, and 6g of methoxysilane-terminated polyether to the vacuum mixing tank and stir until uniform under vacuum. Stop stirring, close the vacuum valve, and release the vacuum by purging with nitrogen to obtain the bio-based polyurethane elastic interface material, which is a black, homogeneous, and fine paste. Store in a container for later use. Example 3:

[0032] Add 300g of bio-based polyurethane prepolymer (I), 30g of tris(2-chloropropyl) phosphate, and 10g of oxazolidine (ALT-201) dehydrating agent to a vacuum mixing tank, evacuate the tank, and stir until the materials are evenly mixed. Stop stirring, close the vacuum valve, and release the vacuum by purging with nitrogen. Add 30g of dehydrated and dried black paste, 3g of multi-walled carbon nanotubes, 50g of polyurethane-grade calcium carbonate, 4g of 3-epoxypropoxypropyltrimethoxysilane, 5g of fumed silica, and 6g of methoxysilane-terminated polyether to the tank and stir until evenly mixed under vacuum. Stop stirring, close the vacuum valve, and release the vacuum by purging with nitrogen to obtain a bio-based polyurethane elastic interface material, which is a black, homogeneous, and fine paste. Store in a container for later use.

[0033] Comparative Example 1: Add 300g of bio-based polyurethane prepolymer (I), 30g of alkyl sulfonate phenyl ester, and 10g of triethyl orthoformate dehydrating agent to a vacuum mixing tank, evacuate the vacuum, and stir until the materials are uniformly mixed. Stop stirring, close the vacuum valve, and release the vacuum by purging with nitrogen. Add 30g of dehydrated and dried black paste, 50g of polyurethane-grade calcium carbonate, 4g of 3-epoxypropoxypropyltrimethoxysilane, 5g of fumed silica, and 6g of methoxysilane-terminated polyether to the tank and stir under vacuum until uniform. Stop stirring, close the vacuum valve, and release the vacuum by purging with nitrogen to obtain a bio-based polyurethane elastic interface material, which is a black, homogeneous, and fine paste. Store in a container for later use.

[0034] Comparative Example 2: Add 300g of bio-based polyurethane prepolymer (II), 30g of tris(2-chloropropyl) phosphate, and 10g of oxazolidine (ALT-201) dehydrating agent to a vacuum mixing tank, evacuate the tank, and stir until the materials are evenly mixed. Stop stirring, close the vacuum valve, and release the vacuum by purging with nitrogen. Add 30g of dehydrated and dried black paste, 3g of multi-walled carbon nanotubes, 50g of polyurethane-grade calcium carbonate, 4g of 3-epoxypropoxypropyltrimethoxysilane, 5g of fumed silica, and 6g of methoxysilane-terminated polyether to the tank and stir until evenly mixed under vacuum. Stop stirring, close the vacuum valve, and release the vacuum by purging with nitrogen to obtain a bio-based polyurethane elastic interface material, which is a black, homogeneous, and fine paste. Store in a container for later use.

[0035] The performance of the bio-based polyurethane elastic interface materials of Examples 1-3 and Comparative Examples 1-2 was tested, and the test results are shown in Table 1. 1. Determination of tensile strength and elongation at break The bio-based polyurethane elastic interface materials obtained in Examples 1-3 and Comparative Examples 1-2 were tested for tensile strength and elongation at break by preparing standard specimens according to GB / T528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber". 2. Determination of surface drying time According to GB / T13477.5-2002 Test Methods for Building Sealing Materials Part 5: Determination of Surface Drying Time; 3. The bio-based polyurethane elastic interface materials prepared in Examples 1-3 and Comparative Examples 1-2 were applied to cleaned tire slice samples, and sound-absorbing cotton was adhered to the tire. The samples were cured for 5 days at 23°C and 50% humidity. The bonded tire sponge assembly was then tested for peel strength, room temperature bond strength, low-temperature resistance, and high-temperature resistance using the following methods.

[0036] (1) Peel strength test The bonded components were tested according to the GB / T15254 180° peel test for rubber until failure. The test was conducted at room temperature and at a speed of 100 mm / min.

[0037] (2) Determination of bonding strength at room temperature The bonded tire sponge was left at 23°C for 48 hours, and the bonding strength was tested at room temperature (23°C) using a high and low temperature tensile testing machine.

[0038] (3) Low temperature resistance test The bonded tire sponge was left at -20℃ for 48 hours, and the bonding strength at -20℃ was tested in a high and low temperature tensile testing machine.

[0039] Low-temperature bond strength retention rate % = (Low-temperature bond strength ÷ Room temperature bond strength) × 100 (4) High temperature resistance test The bonded tire sponge was left at 100℃ for 48 hours, and the bonding strength was tested at 100℃ using a high and low temperature tensile testing machine.

[0040] High-temperature bond strength retention rate % = (High-temperature bond strength ÷ Room temperature bond strength) × 100 (5) Determination of damp heat aging performance The tensile shear strength retention rate was determined after 1000 hours in an environment of 50℃±2℃ and 90%~95% relative humidity.

[0041]

[0042] As can be seen from Examples 1 to 3 in Table 1, the experimental data of tensile strength and elongation at break show that the bio-based polyurethane elastic interface material of the present invention has good mechanical properties and good flexibility. The test results of peel strength, high temperature bond strength retention rate and low temperature bond strength retention rate show that the bio-based single-component polyurethane elastic interface material also exhibits high bonding strength and high and low temperature resistance.

[0043] As can be seen from Table 1, compared with Example 2, in the process of preparing bio-based polyurethane elastic interface materials, if multi-walled carbon nanotube nano-reinforcing agents are not added, the peel strength of the adhesive decreases and the high and low temperature bonding strength retention rate decreases.

[0044] As can be seen from Table 1, comparing Comparative Example 2 with Example 3, in the synthetic bio-based polyurethane prepolymer (II), without the addition of a hydroxyl-terminated liquid polybutadiene rubber reactive adhesive toughening agent, the elongation at break of the adhesive decreases, and its flexibility deteriorates. This indicates that the bio-based polyurethane elastic interface material of the present invention possesses high and low temperature resistance, high peel strength, and excellent durability, ensuring a tight bond between the sound-absorbing cotton and the tire carcass structure. This allows the sound-absorbing cotton to function stably under various complex working conditions, creating a quiet and comfortable environment for drivers and passengers, contributing to sustainable development and advancing the achievement of carbon neutrality goals.

[0045] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A bio-based polyurethane elastic interface material, characterized in that, By weight, it includes the following components: The composition includes 60-80 parts of bio-based polyurethane prepolymer, 6-20 parts of polyurethane-grade filler, 5-10 parts of black paste, 2-5 parts of dehydrating agent, 1-2 parts of thixotropic agent, 0.5-10 parts of viscosity modifier, 0.3-1 part of coupling agent, 0.5-3 parts of nano-reinforcing agent, and 3-8 parts of flame retardant.

2. The bio-based polyurethane elastic interface material according to claim 1, characterized in that, The nano-reinforcing agent is a multi-walled carbon nanotube with the following performance indicators: purity ≥97%, inner diameter 3-5nm, length 10-50μm, and specific surface area ≥200m² / g.

3. The bio-based polyurethane elastic interface material according to claim 1, characterized in that, The viscosity modifier is a low molecular weight methoxysilane-terminated polyether with a molecular weight of 200-400.

4. The bio-based polyurethane elastic interface material according to claim 1, wherein the bio-based polyurethane prepolymer is obtained by polycondensation reaction, characterized in that, By weight, it includes the following components: 40-70 parts of bio-based polyol, 8-25 parts of bio-based isocyanate, 10-25 parts of reactive adhesive toughening agent, 0.2-4 parts of antioxidant, 0.05-0.35 parts of catalyst, and 0.2-5 parts of chain extender; the NCO content of the bio-based polyurethane prepolymer is 2.0-10.0%, and the viscosity is 5000-30000 mPa·s (25℃).

5. The polycondensation reaction of the bio-based polyurethane prepolymer according to claim 4, wherein the bio-based polyol is one or a combination of two of vegetable oil-based polyols and bio-based polyester polyols; the performance indicators of the vegetable oil-based polyol are: hydroxyl value 150-450 mgKOH / g, acid value ≤2.0 mgKOH / g, moisture ≤0.1%, and functionality 2; the performance indicators of the bio-based polyester polyol are: hydroxyl value 50-300 mgKOH / g, acid value ≤2.0 mgKOH / g, moisture ≤0.1%, and functionality 2.

6. The polycondensation reaction of the bio-based polyurethane prepolymer according to claim 4, wherein the bio-based isocyanate is: bio-based 1,5-pentanediisocyanate (PDI), whose performance indicators are: purity ≥98%, acidity ≤0.01%, moisture ≤0.1%, color (platinum-cobalt color number) ≤30, and non-volatile matter ≤0.1%.

7. The polycondensation reaction of the bio-based polyurethane prepolymer according to claim 4, wherein the reactive adhesive toughening agent is a hydroxyl-terminated liquid polybutadiene rubber with the following performance indicators: hydroxyl value 25.0-36.0 mgKOH / g, water content ≤0.1%, and viscosity 4~8 Pa·s (25℃).

8. A method for preparing bio-based polyurethane elastic interface materials, characterized in that, Includes the following steps: The bio-based polyurethane prepolymer, polyurethane-grade filler, dehydrating agent, black paste, and nano-reinforcing toughening agent are added to a mixing tank in proportion, and the mixture is stirred under vacuum until fully mixed. After stopping the stirring and releasing the vacuum, the flame retardant, coupling agent, and viscosity modifier are added to the mixing tank, and the mixture is stirred under vacuum again until fully mixed to obtain the bio-based polyurethane elastic interface material.

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