Bio-based polyurethane buffer material

Abstract

The invention relates to the technical field of polyurethane, in particular to a bio-based polyurethane buffer material. The material is prepared by foaming and curing a bio-based polyurethane prepolymer. The bio-based polyurethane prepolymer is prepared by the following steps: modifying attapulgite with branched polyol containing quaternary ammonium salt and polytetrahydrofuran ether glycol, and then reacting with raw materials such as soybean oil-based polyol, polytetrahydrofuran ether glycol, isophorone diisocyanate and the like. The bio-based polyurethane buffer material provided by the invention has high compression strength and compression modulus, the hysteresis loss rate is lower than 20%, the elastic recovery rate is higher than 99%, and the bio-based polyurethane buffer material shows excellent rebound resilience and energy absorption capacity, and has excellent adaptability and durability in the fields of high rebound resilience and lightweight design.

Description

Technical Field

[0001] The present invention relates to the technical field of polyurethanes, and particularly to a bio-based polyurethane buffer material. Background Art

[0002] With the continuous progress of technology and the rapid development of industry, the demand for high-performance materials is increasing day by day, especially in the field of buffer materials. Traditional polyurethane materials are widely used in the fields of automobiles, construction, electronics, medical treatment, etc. due to their excellent elasticity, wear resistance and processing performance. However, traditional polyurethane materials often exhibit problems such as a decrease in mechanical properties and a weakening of elastic recovery ability under high temperature, high pressure or long-term use environments, which limits their application in some high-end fields.

[0003] In recent years, with the enhancement of environmental awareness and the requirements of sustainable development, bio-based materials have gradually become a research hotspot. Bio-based polyurethane materials have received extensive attention due to their renewable and degradable characteristics. However, bio-based polyurethane materials generally have inferior mechanical properties and elastic recovery ability compared to petroleum-based polyurethane materials, which has become the main obstacle to their popularization and application.

[0004] To overcome this technical problem, researchers have begun to explore ways to improve the performance of bio-based polyurethane materials through modification means. Attapulgite, as a natural mineral filler, has been widely used in the modification of polymer materials due to its unique layered structure and excellent mechanical properties. However, the compatibility between attapulgite and the polyurethane matrix is poor, resulting in unsatisfactory dispersion and reinforcement effects in polyurethane materials. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a bio-based polyurethane buffer material to improve the mechanical properties and elastic recovery ability of bio-based polyurethane.

[0006] Based on the above purpose, the present invention provides a bio-based polyurethane buffer material, which is obtained by foaming and curing a bio-based polyurethane prepolymer;

[0007] Preferably, the foaming is carried out at 30 - 40 °C for 10 - 15 min.

[0008] Preferably, the curing is carried out at room temperature for 20 - 28 h.

[0009] The preparation steps of the bio-based polyurethane prepolymer are as follows:

[0010] (1) Under nitrogen protection, diethanolamine and pentaerythritol tetraacrylate are dissolved in methanol, and stirred at room temperature for 20 - 28 h. After the reaction is completed, the solvent is removed by vacuum distillation, and the obtained crude product is purified by column chromatography to obtain a branched polyol containing tertiary amine;

[0011] (2) Under nitrogen protection, dissolve the tertiary amine-containing branched polyol and hydroquinone in dichloromethane. After stirring evenly, add benzyl chloride dropwise. Heat the reaction system to 40 - 50 °C and reflux with stirring for 20 - 28 h. After the reaction is completed, cool to precipitate a solid, wash it, and dry it under vacuum to obtain a quaternary ammonium salt-containing branched polyol;

[0012] (3) Add the quaternary ammonium salt-containing branched polyol and polytetrahydrofuran ether diol to a mixed solution of deionized water and absolute ethanol. After stirring evenly, add attapulgite, heat to 70 - 80 °C, and reflux with stirring for 5 - 7 h. After the reaction is completed, filter under reduced pressure, wash it, and dry it under vacuum to obtain modified attapulgite;

[0013] (4) Mix soybean oil-based polyol, polytetrahydrofuran ether diol, modified attapulgite, stannous octoate, dimethylcyclohexylamine, and deionized water, stir once, and then add isophorone diisocyanate and polyether-modified silicone oil, stir twice to obtain a bio-based polyurethane prepolymer.

[0014] Preferably, in the step (1), the weight ratio of diethanolamine, pentaerythritol tetraacrylate, and methanol is 2.8:2:8 - 12.

[0015] Preferably, in the step (1), the eluent for column chromatography purification is a mixture of ethyl acetate and petroleum ether with a volume ratio of 1:50.

[0016] Preferably, in the step (2), the weight ratio of the tertiary amine-containing branched polyol, hydroquinone, dichloromethane, and benzyl chloride is 1.5 - 4.5:0.5 - 2.5:5 - 15:0.5 - 1.5.

[0017] Preferably, in the step (3), the weight ratio of the quaternary ammonium salt-containing branched polyol, polytetrahydrofuran ether diol, deionized water, absolute ethanol, and attapulgite is 1.5 - 4.5:0.5 - 4:100 - 150:100 - 150:5 - 15.

[0018] Preferably, in the step (3), the weight-average molecular weight of the polytetrahydrofuran ether diol is 500 - 700.

[0019] Preferably, in the step (4), the weight ratio of the soybean oil-based polyol, polytetrahydrofuran ether diol, modified attapulgite, stannous octoate, dimethylcyclohexylamine, deionized water, isophorone diisocyanate, and polyether-modified silicone oil is 40 - 60:20 - 40:5 - 15:0.4 - 0.6:2 - 3:3 - 5:40 - 70:3 - 8.

[0020] Preferably, in the step (4), the weight-average molecular weight of the polytetrahydrofuran ether diol is 1500 - 2500.

[0021] Preferably, in the step (4), the hydroxyl value of the soybean oil-based polyol is 240-260 mgKOH / g, and the viscosity is 11000-13000 mPa·s.

[0022] Preferably, in the step (4), the first stirring is carried out at a speed of 2000-3000 r / min for 60-100 s, and the second stirring is carried out at a speed of 1000-2000 r / min for 30-60 s.

[0023] Advantages of the present invention:

[0024] The present invention provides a bio-based polyurethane buffer material with high compressive strength and compressive modulus, enabling it to effectively resist deformation when subjected to external pressure, providing reliable support and protection for various applications. Its hysteresis loss rate is less than 20%, and the elastic recovery rate is higher than 99%, indicating that the material can quickly recover to its original shape after experiencing deformation, with excellent resilience and energy absorption capacity. These characteristics make the material show more excellent adaptability and durability in fields requiring high resilience and lightweight design.

[0025] In addition, by using quaternary ammonium salt-containing branched polyol and low molecular weight polytetrahydrofuran ether diol to intercalate and modify attapulgite, the prepared polyurethane buffer material has been significantly improved in mechanical properties and elastic characteristics. This modification method effectively improves the compatibility between attapulgite and the polyurethane matrix, promotes the formation of the polyurethane network, and thus can more effectively disperse stress when stressed, reducing the risk of permanent deformation. Specific embodiments

[0026] To make the purpose, technical solutions and advantages of the present invention clearer and more understandable, the following further details the present invention with specific embodiments.

[0027] In the specific embodiments of the present invention, the attapulgite is a powder passed through a 200-mesh sieve; the hydroxyl value of the soybean oil-based polyol is 252 mgKOH / g, and the viscosity is 12000 mPa·s; the polytetrahydrofuran ether diol is purchased from Shandong Weishang Chemical Co., Ltd.; the model of the polyether modified silicone oil is Dow Corning DC193.

[0028] Example 1:

[0029] (1) Under nitrogen protection, 2.8 g of diethanolamine and 2 g of pentaerythritol tetraacrylate are dissolved in 8 g of methanol, and stirred at room temperature for 20 h. After the reaction is completed, the solvent is removed by vacuum distillation, and the obtained crude product is purified by column chromatography (the eluent is ethyl acetate / petroleum ether, volume ratio 1:50) to obtain a tertiary amine-containing branched polyol;

[0030] (2) Under nitrogen protection, 1.5 g of a branched polyol containing a tertiary amine and 0.5 g of hydroquinone were dissolved in 5 g of dichloromethane. After stirring evenly, 0.5 g of benzyl chloride was added dropwise. The reaction system was heated to 40 °C and stirred under reflux for 20 h. After the reaction was completed, it was cooled to precipitate a solid. The product was washed with ether and then dried under vacuum to obtain a branched polyol containing a quaternary ammonium salt;

[0031] (3) 1.5 g of a branched polyol containing a quaternary ammonium salt and 0.5 g of polytetrahydrofuran ether diol with a weight average molecular weight of 650 were added to a mixed solution of 100 g of deionized water and 100 g of absolute ethanol. After stirring evenly, 5 g of attapulgite was added. The mixture was heated to 70 °C and stirred under reflux for 5 h. After the reaction was completed, it was filtered under reduced pressure. The obtained solid was washed successively with water and ethanol, and finally dried under vacuum to obtain modified attapulgite;

[0032] (4) 40 g of a soybean oil-based polyol, 20 g of polytetrahydrofuran ether diol with a weight average molecular weight of 2000, 5 g of modified attapulgite, 0.4 g of stannous octoate, 2 g of dimethylcyclohexylamine, and 3 g of deionized water were mixed and stirred at a speed of 2000 r / min for 60 s. Then, 40 g of isophorone diisocyanate and 3 g of polyether-modified silicone oil were added and stirred at a speed of 1000 r / min for 30 s to obtain a bio-based polyurethane prepolymer;

[0033] (5) The bio-based polyurethane prepolymer was poured into a mold for foaming, foamed at 30 °C for 10 min, and then cured at room temperature for 20 h to obtain a bio-based polyurethane buffer material.

[0034] Example 2:

[0035] (1) Under nitrogen protection, 2.8 g of diethanolamine and 2 g of pentaerythritol tetraacrylate were dissolved in 10 g of methanol. The reaction was stirred at room temperature for 24 h. After the reaction was completed, the solvent was removed by distillation under reduced pressure. The obtained crude product was purified by column chromatography (the eluent was ethyl acetate / petroleum ether, volume ratio 1:50) to obtain a branched polyol containing a tertiary amine;

[0036] (2) Under nitrogen protection, 3 g of a branched polyol containing a tertiary amine and 1 g of hydroquinone were dissolved in 8 g of dichloromethane. After stirring evenly, 1 g of benzyl chloride was added dropwise. The reaction system was heated to 45 °C and stirred under reflux for 24 h. After the reaction was completed, it was cooled to precipitate a solid. The product was washed with ether and then dried under vacuum to obtain a branched polyol containing a quaternary ammonium salt;

[0037] (3) Add 3 g of quaternary ammonium salt-containing branched polyol and 2 g of polytetrahydrofuran ether diol with a weight average molecular weight of 650 to a mixed solution of 120 g of deionized water and 120 g of absolute ethanol. After stirring evenly, add 10 g of attapulgite, heat to 75 °C, reflux and stir for 6 h. After the reaction is completed, perform suction filtration under reduced pressure. The obtained solid is washed successively with water and ethanol, and finally dried in vacuo to obtain modified attapulgite;

[0038] (4) Mix 50 g of soybean oil-based polyol, 30 g of polytetrahydrofuran ether diol with a weight average molecular weight of 2000, 10 g of modified attapulgite, 0.5 g of stannous octoate, 2.5 g of dimethylcyclohexylamine and 4 g of deionized water, stir at a speed of 2500 r / min for 80 s, then add 55 g of isophorone diisocyanate and 5 g of polyether-modified silicone oil, and stir at a speed of 1500 r / min for 45 s to obtain a bio-based polyurethane prepolymer;

[0039] (5) Pour the bio-based polyurethane prepolymer into a mold for foaming, foam at 35 °C for 12 min, and then cure at room temperature for 24 h to obtain a bio-based polyurethane buffer material.

[0040] Example 3:

[0041] (1) Under nitrogen protection, dissolve 2.8 g of diethanolamine and 2 g of pentaerythritol tetraacrylate in 12 g of methanol, stir and react at room temperature for 28 h. After the reaction is completed, remove the solvent by distillation under reduced pressure. The obtained crude product is purified by column chromatography (the eluent is ethyl acetate / petroleum ether, volume ratio 1:50) to obtain a tertiary amine-containing branched polyol;

[0042] (2) Under nitrogen protection, dissolve 4.5 g of tertiary amine-containing branched polyol and 2.5 g of hydroquinone in 15 g of dichloromethane. After stirring evenly, add 1.5 g of benzyl chloride dropwise, heat the reaction system to 50 °C, reflux and stir for 28 h. After the reaction is completed, cool to precipitate a solid. The product is washed with ether and then dried in vacuo to obtain a quaternary ammonium salt-containing branched polyol;

[0043] (3) Add 4.5 g of quaternary ammonium salt-containing branched polyol and 4 g of polytetrahydrofuran ether diol with a weight average molecular weight of 650 to a mixed solution of 150 g of deionized water and 150 g of absolute ethanol. After stirring evenly, add 15 g of attapulgite, heat to 80 °C, reflux and stir for 7 h. After the reaction is completed, perform suction filtration under reduced pressure. The obtained solid is washed successively with water and ethanol, and finally dried in vacuo to obtain modified attapulgite;

[0044] (4) Mix 60 g of soybean oil-based polyol, 40 g of polytetrahydrofuran ether diol with a weight average molecular weight of 2000, 15 g of modified attapulgite, 0.6 g of stannous octoate, 3 g of dimethylcyclohexylamine, and 5 g of deionized water, stir at a speed of 3000 r / min for 100 s, then add 70 g of isophorone diisocyanate and 8 g of polyether-modified silicone oil, and stir at a speed of 2000 r / min for 60 s to obtain a bio-based polyurethane prepolymer;

[0045] (5) Pour the bio-based polyurethane prepolymer into a mold for foaming, foam at 40 °C for 15 min, and then cure at room temperature for 28 h to obtain a bio-based polyurethane buffer material.

[0046] Comparative Example 1:

[0047] The difference between Comparative Example 1 and Example 2 is that the quaternary ammonium salt-containing branched polyol in step (3) is replaced with a tertiary amine-containing branched polyol;

[0048] The specific steps are as follows:

[0049] (1) Under nitrogen protection, dissolve 2.8 g of diethanolamine and 2 g of pentaerythritol tetraacrylate in 10 g of methanol, stir and react at room temperature for 24 h. After the reaction is completed, remove the solvent by vacuum distillation. The obtained crude product is purified by column chromatography (the eluent is ethyl acetate / petroleum ether, volume ratio 1:50) to obtain a tertiary amine-containing branched polyol;

[0050] (2) Add 3 g of the tertiary amine-containing branched polyol and 2 g of polytetrahydrofuran ether diol with a weight average molecular weight of 650 to a mixed solution of 120 g of deionized water and 120 g of absolute ethanol. After stirring evenly, add 10 g of attapulgite, heat to 75 °C, reflux and stir for 6 h. After the reaction is completed, filter under reduced pressure. The obtained solid is washed successively with water and ethanol, and finally dried in vacuum to obtain modified attapulgite;

[0051] (3) Mix 50 g of soybean oil-based polyol, 30 g of polytetrahydrofuran ether diol with a weight average molecular weight of 2000, 10 g of modified attapulgite, 0.5 g of stannous octoate, 2.5 g of dimethylcyclohexylamine, and 4 g of deionized water, stir at a speed of 2500 r / min for 80 s, then add 55 g of isophorone diisocyanate and 5 g of polyether-modified silicone oil, and stir at a speed of 1500 r / min for 45 s to obtain a bio-based polyurethane prepolymer;

[0052] (4) Pour the bio-based polyurethane prepolymer into a mold for foaming, foam at 35 °C for 12 min, and then cure at room temperature for 24 h to obtain a bio-based polyurethane buffer material.

[0053] Comparative Example 2:

[0054] The difference between Comparative Example 2 and Example 2 is that the polytetrahydrofuran glycol with a weight-average molecular weight of 650 in step (3) is replaced with polytetrahydrofuran glycol with a weight-average molecular weight of 2000;

[0055] The specific steps are as follows:

[0056] (1) Under nitrogen protection, 2.8 g of diethanolamine and 2 g of pentaerythritol tetraacrylate are dissolved in 10 g of methanol, and the mixture is stirred at room temperature for 24 h. After the reaction is completed, the solvent is removed by vacuum distillation. The obtained crude product is purified by column chromatography (the eluent is ethyl acetate / petroleum ether, volume ratio 1:50) to obtain a branched polyol containing a tertiary amine;

[0057] (2) Under nitrogen protection, 3 g of the branched polyol containing a tertiary amine and 1 g of hydroquinone are dissolved in 8 g of dichloromethane. After stirring evenly, 1 g of benzyl chloride is added dropwise. The reaction system is heated to 45 °C and stirred under reflux for 24 h. After the reaction is completed, the mixture is cooled to precipitate a solid. The product is washed with ether and then dried in vacuo to obtain a branched polyol containing a quaternary ammonium salt;

[0058] (3) 3 g of the branched polyol containing a quaternary ammonium salt and 2 g of polytetrahydrofuran glycol with a weight-average molecular weight of 2000 are added to a mixed solution of 120 g of deionized water and 120 g of absolute ethanol. After stirring evenly, 10 g of attapulgite is added, and the mixture is heated to 75 °C and stirred under reflux for 6 h. After the reaction is completed, it is filtered under reduced pressure. The obtained solid is washed successively with water and ethanol, and finally dried in vacuo to obtain modified attapulgite;

[0059] (4) 50 g of soybean oil-based polyol, 30 g of polytetrahydrofuran glycol with a weight-average molecular weight of 2000, 10 g of modified attapulgite, 0.5 g of stannous octoate, 2.5 g of dimethylcyclohexylamine, and 4 g of deionized water are mixed and stirred at a speed of 2500 r / min for 80 s. Then, 55 g of isophorone diisocyanate and 5 g of polyether-modified silicone oil are added, and the mixture is stirred at a speed of 1500 r / min for 45 s to obtain a bio-based polyurethane prepolymer;

[0060] (5) The bio-based polyurethane prepolymer is poured into a mold for foaming, foamed at 35 °C for 12 min, and then cured at room temperature for 24 h to obtain a bio-based polyurethane buffer material.

[0061] Comparative Example 3:

[0062] The difference between Comparative Example 3 and Example 2 is that the branched polyol containing a quaternary ammonium salt in step (3) is replaced with cetyltrimethylammonium chloride;

[0063] The specific steps are as follows:

[0064] (1) Add 3 g of cetyltrimethylammonium chloride and 2 g of polytetrahydrofuran ether diol with a weight average molecular weight of 650 to a mixed solution of 120 g of deionized water and 120 g of absolute ethanol. After stirring evenly, add 10 g of attapulgite, heat to 75 °C, reflux and stir for 6 h. After the reaction is completed, carry out vacuum filtration. The obtained solid is washed successively with water and ethanol, and finally dried in vacuum to obtain modified attapulgite;

[0065] (2) Mix 50 g of soybean oil-based polyol, 30 g of polytetrahydrofuran ether diol with a weight average molecular weight of 2000, 10 g of modified attapulgite, 0.5 g of stannous octoate, 2.5 g of dimethylcyclohexylamine and 4 g of deionized water, stir at a speed of 2500 r / min for 80 s, then add 55 g of isophorone diisocyanate and 5 g of polyether-modified silicone oil, and stir at a speed of 1500 r / min for 45 s to obtain a bio-based polyurethane prepolymer;

[0066] (3) Pour the bio-based polyurethane prepolymer into a mold for foaming, foam at 35 °C for 12 min, and then cure at room temperature for 24 h to obtain a bio-based polyurethane buffer material.

[0067] Comparative Example 4:

[0068] The difference between Comparative Example 4 and Example 2 is that the modified attapulgite in step (3) is replaced with attapulgite;

[0069] The specific steps are as follows:

[0070] (1) Mix 50 g of soybean oil-based polyol, 30 g of polytetrahydrofuran ether diol with a weight average molecular weight of 2000, 10 g of attapulgite, 0.5 g of stannous octoate, 2.5 g of dimethylcyclohexylamine and 4 g of deionized water, stir at a speed of 2500 r / min for 80 s, then add 55 g of isophorone diisocyanate and 5 g of polyether-modified silicone oil, and stir at a speed of 1500 r / min for 45 s to obtain a bio-based polyurethane prepolymer;

[0071] (2) Pour the bio-based polyurethane prepolymer into a mold for foaming, foam at 35 °C for 12 min, and then cure at room temperature for 24 h to obtain a bio-based polyurethane buffer material.

[0072] Performance test:

[0073] Use a universal testing machine to test and analyze the mechanical properties of the polyurethane buffer material, and determine it by the method of ASTM D3574-05. The specimen size is 50 mm × 25 mm (diameter × thickness), and the compression rate is 50 mm / min.

[0074] Compression hardness: The polyurethane cushioning material was subjected to a 50% compression hardness test, and the compression modulus was measured according to the GB / T8813-2008 standard method. The results are shown in Table 1.

[0075] Hysteresis loss and elastic recovery: Hysteresis loss tests were conducted on polyurethane cushioning materials. The foam was rapidly compressed to 75% strain, and then the stress was unloaded at the same rate until the indenter was reset. The hysteresis loss rate and elastic recovery rate of the foam were calculated according to the following formulas. The results are shown in Table 1.

[0076]

[0077] Table 1 Performance test results

[0078]

[0079]

[0080] Data Analysis:

[0081] From the data of Examples 1-3 in Table 1, it can be seen that the bio-based polyurethane cushioning material prepared by the present invention has high compressive strength and compression modulus, which indicates that the material exhibits excellent mechanical properties when subjected to external pressure. This high strength and high modulus property means that the material can effectively resist deformation and provide good support and protection when subjected to impact or compression. In addition, its hysteresis loss rate is less than 20% and its elastic recovery rate is higher than 99%, which indicates that the material can quickly return to its original shape after deformation and has excellent resilience and energy absorption capacity. Such performance makes the bio-based polyurethane cushioning material exhibit better adaptability and durability in various applications, especially in situations where high resilience and lightweight design are required.

[0082] As can be seen from the data of Example 2 and Comparative Example 1 in Table 1, relative to the branched polyol containing tertiary amine, the branched polyol containing quaternary ammonium salt can effectively improve the compressive strength and compression modulus of polyurethane cushioning material, the most important thing is, significantly reduce the hysteresis loss rate and improve the elastic recovery rate, this is mainly due to the quaternary ammonium salt in the branched polyol containing quaternary ammonium salt can be intercalated in the interlayer of attapulgite by ion exchange, on the one hand improve the interlayer spacing of attapulgite, on the other hand introduce polyol, so that attapulgite can be cross-linked by the polyol and diisocyanate in the interlayer, thereby improving the mechanical properties and elastic properties of polyurethane material. Specifically, the introduction of quaternary ammonium salt not only enhances the compatibility between attapulgite and polyurethane matrix, but also promotes the formation of polyurethane network, and the attapulgite of uniformly dispersed intercalation modification in the polyurethane network can more effectively disperse stress when stressed, reducing the permanent deformation of material.

[0083] From the data of Example 2 and Comparative Example 2 in Table 1, it can be seen that during the intercalation modification, low-molecular-weight polytetrahydrofuran ether diol can more effectively improve the buffering performance of the polyurethane buffer material. This is mainly because low-molecular-weight polytetrahydrofuran ether diol has lower steric hindrance and can be more effectively intercalated into attapulgite, thus cooperating with the quaternary ammonium salt-containing branched polyol and diisocyanate to form a more stable crosslinked structure, which helps to improve the flexibility and impact resistance of the polyurethane material, enabling the material to better restore its shape when subjected to external forces and reducing the risk of damage and deformation.

[0084] From the data of Example 2 and Comparative Example 3 in Table 1, it can be seen that compared with the traditional cetyltrimethylammonium chloride intercalation modification, the intercalation modification with the quaternary ammonium salt-containing branched polyol prepared by the present invention can significantly improve the compression performance and recovery performance of the polyurethane buffer material. This is mainly because the quaternary ammonium salt-containing branched polyol effectively regulates the layer spacing of attapulgite and improves the compatibility of attapulgite in the polyurethane matrix.

[0085] From the data of Example 2 and Comparative Example 4 in Table 1, it can be seen that compared with directly adding attapulgite, the attapulgite intercalation modified with the quaternary ammonium salt-containing branched polyol and polytetrahydrofuran ether diol with a weight average molecular weight of 650 can significantly improve the compression performance and recovery performance of the polyurethane buffer material. This is mainly because the quaternary ammonium salt-containing branched polyol and polytetrahydrofuran ether diol coordinately regulate the interlayer structure of attapulgite and promote the formation of the polyurethane network structure.

[0086] Those of ordinary skill in the art should understand that: the discussion of any above embodiment is only exemplary and is not intended to imply that the scope of the present invention is limited to these examples; under the concept of the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the present invention as described above, which are not provided in detail for the sake of brevity.

Claims

1. A bio-based polyurethane buffer material, characterized in that, It is obtained by foaming and curing a bio-based polyurethane prepolymer; The preparation steps of the bio-based polyurethane prepolymer are as follows: (1) Under nitrogen protection, dissolve diethanolamine and pentaerythritol tetraacrylate in methanol, stir and react at room temperature for 20 - 28 h. After the reaction is completed, remove the solvent by vacuum distillation. The obtained crude product is purified by column chromatography to obtain a branched polyol containing tertiary amine; (2) Under nitrogen protection, dissolve the branched polyol containing tertiary amine and hydroquinone in dichloromethane. After stirring evenly, dropwise add benzyl chloride. Heat the reaction system to 40 - 50 °C and reflux and stir for 20 - 28 h. After the reaction ends, cool to precipitate a solid, wash, and dry in vacuum to obtain a branched polyol containing quaternary ammonium salt; (3) Add the branched polyol containing quaternary ammonium salt and polytetrahydrofuran ether diol to a mixed solution of deionized water and absolute ethanol. After stirring evenly, add attapulgite, heat to 70 - 80 °C, reflux and stir for 5 - 7 h. After the reaction is completed, filter under reduced pressure, wash, and dry in vacuum to obtain modified attapulgite; (4) Mix soybean oil-based polyol, polytetrahydrofuran ether diol, modified attapulgite, stannous octoate, dimethylcyclohexylamine, and deionized water, stir once, then add isophorone diisocyanate and polyether-modified silicone oil, and stir twice to obtain a bio-based polyurethane prepolymer; In step (3), the weight ratio of the branched polyol containing quaternary ammonium salt, polytetrahydrofuran ether diol, deionized water, absolute ethanol, and attapulgite is 1.5 - 4.5:0.5 - 4:100 - 150:100 - 150:5 - 15; In step (3), the weight-average molecular weight of the polytetrahydrofuran ether diol is 500 - 700; In step (4), the weight ratio of soybean oil-based polyol, polytetrahydrofuran ether diol, modified attapulgite, stannous octoate, dimethylcyclohexylamine, deionized water, isophorone diisocyanate, and polyether-modified silicone oil is 40 - 60:20 - 40:5 - 15:0.4 - 0.6:2 - 3:3 - 5:40 - 70:3 - 8.

2. The bio-based polyurethane buffer material according to claim 1, characterized in that In step (1), the weight ratio of diethanolamine, pentaerythritol tetraacrylate, and methanol is 2.8:2:8 - 12.

3. The bio-based polyurethane buffer material according to claim 1, characterized in that, In step (1), the eluent for column chromatography purification is a mixture of ethyl acetate and petroleum ether with a volume ratio of 1:

50.

4. The bio-based polyurethane buffer material according to claim  1, wherein In step (2), the weight ratio of the branched polyol containing tertiary amine, hydroquinone, dichloromethane, and benzyl chloride is 1.5 - 4.5:0.5 - 2.5:5 - 15:0.5 - 1.

5.

5. The bio-based polyurethane buffer material according to claim 1, wherein In step (4), the weight-average molecular weight of the polytetrahydrofuran ether diol is 1500 - 2500.

6. The bio-based polyurethane buffer material according to claim 1, wherein In step (4), the hydroxyl value of the soybean oil-based polyol is 240 - 260 mgKOH / g, and the viscosity is 11000 - 13000 mPa·s.

7. The bio-based polyurethane buffer material according to claim 1, characterized in that, In step (4), the first stirring is: stirring at a speed of 2000 - 3000 r / min for 60 - 100 s, and the second stirring is: stirring at a speed of 1000 - 2000 r / min for 30 - 60 s.

8. The bio-based polyurethane buffer material according to claim 1, wherein The foaming is: foaming at 30 - 40 °C for 10 - 15 min.

9. The bio-based polyurethane buffer material according to claim 1, characterized in that, The curing is: curing at room temperature for 20 - 28 h.

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