High-adhesion bio-based polyurethane hot melt adhesive and preparation method thereof

Abstract

The invention discloses a high-adhesion bio-based polyurethane hot melt adhesive and a preparation method thereof. Preparation raw materials of the adhesive comprise the following components in parts by weight: 10 to 30 parts of isocyanate, 5 to 20 parts of polyether glycol, 10 to 40 parts of polyphthalic anhydride-diethylene glycol ester glycol, 10 to 40 parts of polysebacic acid 3-methyl-1, 5-pentanediol ester glycol, 15 to 40 parts of bio-based polyol, 10 to 20 parts of tackifying resin, 0.05 to 0.5 part of a catalyst and 10 to 20 parts of a filler. The high-adhesion bio-based polyurethane hot melt adhesive can be obtained by mixing and reacting the raw materials in parts by weight. The performance of the high-adhesion bio-based single-component moisture curing reaction type polyurethane edge sealing hot melt adhesive can meet the use requirements of clients, the use of petroleum-based raw materials is effectively reduced, bio-based raw materials are introduced, and effective support is provided for reproducibility and degradability. The product is suitable for bonding various plates with PVC, PET and other edge sealing materials in the fields of furniture, building materials and the like, and has the characteristics of high initial adhesion, rapid curing, damp and heat resistance and degradability.

Description

Technical Field

[0001] This invention pertains to hot melt adhesive preparation technology, and particularly relates to a high-adhesion bio-based polyurethane hot melt adhesive and its preparation method. Background Technology

[0002] In the field of edge banding for wooden furniture and building materials, while polyurethane hot melt adhesives possess excellent bonding and processing properties, they still have limitations in terms of long-term weather resistance and environmental sustainability. Currently, polyurethane hot melt edge banding adhesives on the market mainly use diphenylmethane diisocyanate (MDI) as the isocyanate component, combined with petroleum-based polyethers or polyester polyols. Although this system is technologically mature, its raw materials are entirely dependent on non-renewable petroleum resources. Therefore, using renewable biomass resources to replace traditional petroleum-based raw materials has become an urgent need and an inevitable trend for technological upgrading in this field.

[0003] In the research and development of bio-based polyurethane adhesives, existing technologies mainly attempt to replace petroleum-based polyols with polyols derived from vegetable oils such as castor oil and soybean oil. Although these bio-based raw materials are renewable, they have significant performance defects: the hydroxyl values ​​of vegetable oil polyols are generally low, resulting in insufficient density of the polymer crosslinking network formed by their reaction with MDI, leading to poor mechanical strength and heat resistance of the final product; the long-chain fatty acids in the molecular structure of vegetable oils result in excessively high product flexibility and insufficient initial tack, easily causing "edge opening" in edge sealing processes; in addition, these bio-based polyols usually have high viscosity and poor flow and processing performance, posing challenges to mixing and application processes in production. Traditional polyurethane hot melt adhesives are difficult to degrade naturally after disposal, causing a serious environmental burden. Although existing research has focused on the development of biodegradable polyurethanes, most solutions require sacrificing the initial properties of the material or require specific conditions to achieve degradation, making it difficult to meet practical application requirements. Especially for MDI systems, due to their inherent chemical stability, achieving controlled degradation is even more challenging.

[0004] In summary, there is an urgent need to develop a bio-based polyurethane hot melt sealing adhesive that combines high bonding strength, good weather resistance, and environmental friendliness. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a highly adhesive bio-based polyurethane hot melt adhesive and its preparation method.

[0006] The objective of this invention is achieved through the following technical solution: In a first aspect, the present invention provides a highly adhesive bio-based polyurethane hot melt adhesive, the raw materials for which comprise the following components by weight: 10-30 parts of isocyanate 5-20 parts of polyether diol 10-40 parts of poly(phthalic anhydride-diethylene glycol) diol 10-40 parts of poly(3-methyl-1,5-pentanediol sebacate) 15-40 parts of bio-based polyols 10-20 parts of tackifying resin Catalyst 0.05~0.5 parts 10-20 parts of filler.

[0007] Furthermore, the hot melt adhesive contains 0.9-2.5% free isocyanate groups by mass; the isocyanate is composed of one or more of diphenylmethane-4,4-diisocyanate (MDI) and 4,4-dicyclohexylmethane diisocyanate mixed in any proportion.

[0008] Furthermore, the hydroxyl value of the poly(phthalic anhydride-diethylene glycol diol), poly(3-methyl-1,5-pentanediol sebacic acid) diol, and the bio-based polyol is 18~60 mgKOH / g, and the acid value is 0.1~2 mgKOH / g.

[0009] Furthermore, the polyether diol is composed of one or more of PPG400, PPG1000, PEG400, and PEG1000 mixed in any proportion.

[0010] Furthermore, the bio-based polyol is composed of one or more of the following: epoxidized castor oil polyol, castor oil, bio-based diol PTMG, and self-made high initial tack and high adhesion bio-based diol, mixed in any proportion.

[0011] Furthermore, the tackifying resin is composed of one or more of Covestro Desmopan® TPU 3695AU, petroleum resin, and rosin resin mixed in any proportion.

[0012] Furthermore, the first catalyst is composed of one or more of DABCO® MB20, DABCO® MB35, and DABCO® MB125 mixed in any proportion.

[0013] Furthermore, the filler is composed of one or more of hydroxymethylated lignin, epoxidized lignin, and fumed silica in any proportion.

[0014] Furthermore, the epoxidized castor oil polyol is prepared through the following steps: (1) Castor oil is mixed with formic acid or acetic acid in a 1:1 molar ratio, and then an oxidant is slowly added dropwise under stirring. After reacting at 20-60°C for 2-6 hours, epoxidized castor oil can be obtained. The oxidant is composed of one or more of peroxyformic acid, peracetic acid or hydrogen peroxide in any proportion. (2) The epoxidized castor oil obtained in step (1) is mixed with the ring-opening agent at a molar ratio of 1:3, and sulfuric acid with a mass concentration of 98% is added. The mixture is reacted at 40-80℃ for 2-5 hours to obtain an intermediate product. The ring-opening agent is methanol or ethylene glycol. The amount of sulfuric acid added is 0.5%-5% of the total mass of the reaction system.

[0015] (3) Neutralize, wash with water and dry the intermediate product of step (2) to obtain epoxidized castor oil polyol.

[0016] Furthermore, the self-made high initial tack and high adhesion bio-based diol is prepared by the following method: A self-made high-tack, high-adhesion bio-based diol with acid value less than 0.5 mgKOH / g and hydroxyl value of 33-39 mgKOH / g can be prepared by esterification and polycondensation of 2,5-furandicarboxylic acid (FDCA), succinic acid, 1,4-butanediol (BDO), 1,3-propanediol (PDO) and terephthalic acid (PTA) in a molar ratio of 0.7~0.9:0.2~0.4:1.0:0.1~0.2:0.1~0.3 and a second catalyst of 0.1%~0.5% of the total reaction mass.

[0017] The second catalyst is composed of one or more of tetrabutyl titanate, zinc acetate, or antimony oxide mixed in any proportion; the esterification polycondensation reaction is carried out under inert gas protection, the reaction temperature is 180~240℃, the reaction pressure is 0.1~0.5 MPa, and the reaction time is 4~10 hours.

[0018] Secondly, the present invention provides a method for preparing a highly adhesive bio-based polyurethane hot melt adhesive, comprising the following steps: S1: Add 5-20 parts by weight of polyether diol, 5-40 parts by weight of epoxidized castor oil polyol, 10-40 parts by weight of polyphthalic anhydride-diethylene glycol diol, 15-40 parts by weight of bio-based polyol, 10-20 parts by weight of tackifying resin, and 0.05-0.5 parts by weight of catalyst to a reactor, heat to 100-150℃ for vacuum dehydration for 2 hours, and then add 10-20 parts by weight of filler for dispersion; S2: Then, dehydrate under vacuum at 120~140℃ for 2 hours, cool down to 90~110℃ and add 10~30 parts by weight of isocyanate, control the R value of the colloid to be 0.9~1.5, and then react at 110~120℃ under vacuum of -0.1MPa for 2 hours before discharging to obtain a high-adhesion bio-based polyurethane hot melt adhesive.

[0019] The present invention has the following advantages over the prior art: (1) The polyurethane hot melt adhesive of the present invention exhibits excellent bonding effect under high temperature conditions, and also has excellent post-bonding strength and material breaking effect performance, ensuring the structural reliability of long-term use; and it shows wide adaptability to a variety of edge sealing strip materials, which can meet the edge sealing process requirements of different substrates. (2) The bio-based content of this invention is over 60%, which greatly reduces the dependence on petroleum-based resources; and the formula and process design take into account the feasibility of large-scale production, enabling large-scale industrial production. (3) The hot melt adhesive exhibits good weather resistance under various environmental conditions, and can adapt to changes in external factors such as temperature and humidity, and maintain stable performance; its final bonding strength is high, which ensures the durability and safety of the edge sealing structure during long-term use. (4) The product incorporates renewable and biodegradable bio-based raw materials, reducing the persistent environmental burden from the source; (5) The preparation method provided is simple, the reaction conditions are mild and easy to control, and no complex equipment or harsh conditions are required, which helps to reduce production energy consumption and operation difficulty; at the same time, the raw materials are widely available and the cost is low. Attached Figure Description Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail with reference to the embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0022] In the examples, epoxidized castor oil polyols were prepared through the following steps: (1) Mix 86.6 kg of commercial castor oil with 12.85 kg of formic acid, and then slowly add 30 kg of peracetic acid and hydrogen peroxide with a mass ratio of 1:2 and a volume concentration of 35% while stirring. After reacting at 25°C for 3 hours, epoxidized castor oil can be obtained. (2) The epoxidized castor oil obtained in step (1) was mixed with 13.4 kg of methanol, and 2.09 kg of sulfuric acid with a mass concentration of 98% was added. The mixture was reacted at 40°C for 3 hours to obtain the intermediate product. (3) Neutralize, wash with water and dry the intermediate product of step (2) to obtain epoxidized castor oil polyol.

[0023] The self-made high initial tack and high adhesion bio-based diol in the example was prepared by the following method: 47.89 kg of 2,5-furandicarboxylic acid (FDCA), 9.07 kg of succinic acid, 34.59 kg of 1,4-butanediol (BDO), 5.84 kg of 1,3-propanediol (PDO), and 19.12 kg of terephthalic acid (PTA) were subjected to an esterification polycondensation reaction with 0.233 kg of tetrabutyl titanate. The esterification polycondensation reaction was carried out under inert gas protection at a reaction temperature of 200℃, a reaction pressure of 0.5 MPa, and a reaction time of 6 hours to obtain a self-made high-tack, high-adhesion bio-based diol with terephthalic acid having an acid value of 0.4 mgKOH / g and a hydroxyl value of 36 mgKOH / g.

[0024] Example 1 In a first aspect, this embodiment provides a highly adhesive bio-based polyurethane hot melt adhesive, the raw materials of which include the following components by weight: 10 parts of isocyanate 5 parts polyether diol 15 parts of poly(phthalic anhydride-diethylene glycol) diol 20 parts of bio-based polyols 10 parts of tackifying resin 0.1 parts of the first catalyst 15 parts of filler.

[0025] Secondly, this embodiment provides a method for preparing a highly adhesive bio-based polyurethane hot melt adhesive, comprising the following steps: S1: Add 2.5 kg PPG1000, 12.5 kg epoxidized castor oil polyol, 7.5 kg poly(phthalic anhydride-diethylene glycol diol), 10.0 kg castor oil, 5.0 kg Desmopan® TPU 3695AU, and 0.05 kg DABCO® MB125 to a reactor, heat to 120~130℃, vacuum dehydrate for 2 hours, and then add 7.5 kg hydroxymethylated lignin for dispersion; S2: Then dehydrate under vacuum at 120~130℃ for 1.5h; after cooling to 100℃, add 5.0kg of diphenylmethane diisocyanate (MDI), control the R value of the colloid at 1.06, then heat to 110~115℃, react for 2h under vacuum of -0.1MPa, then turn off the stirring and discharge the material to obtain a high-adhesion bio-based polyurethane hot melt adhesive, which can be stored in vacuum or nitrogen-protected packaging.

[0026] Example 2 In a first aspect, this embodiment provides a highly adhesive bio-based polyurethane hot melt adhesive, the raw materials of which include the following components by weight: 9 parts of isocyanate 5 parts polyether diol 15.1 parts of poly(phthalic anhydride-diethylene glycol) diol 20.2 parts of bio-based polyols 10 parts of tackifying resin 0.1 parts of the first catalyst 15.1 parts of filler.

[0027] Secondly, this embodiment provides a method for preparing a highly adhesive bio-based polyurethane hot melt adhesive, comprising the following steps: S1: Add 2.5 kg PPG1000, 12.5 kg epoxidized castor oil polyol, 7.5 kg poly(phthalic anhydride-diethylene glycol diol), 5.0 kg castor oil, 5.0 kg Desmopan® TPU 3695AU, and 0.05 kg DABCO® MB125 to a reactor, heat to 120~130℃, vacuum dehydrate for 2 hours, and then add 7.5 kg hydroxymethylated lignin for dispersion; S2: Then dehydrate under vacuum at 120~130℃ for 1.5h; after cooling to 100℃, add 4.50kg of diphenylmethane diisocyanate (MDI), control the R value of the colloid at 1.22, then heat to 110~115℃, react under vacuum of -0.1MPa for 2h, then turn off the stirring and discharge the material to obtain a high-adhesion bio-based polyurethane hot melt adhesive, which can be stored in vacuum or nitrogen-protected packaging.

[0028] Example 3 In a first aspect, this embodiment provides a highly adhesive bio-based polyurethane hot melt adhesive, the raw materials of which include the following components by weight: 9.6 parts isocyanate 5 parts polyether diol 15 parts of poly(phthalic anhydride-diethylene glycol) diol 10 parts of poly(3-methyl-1,5-pentanediol sebacate) diol 10 parts of bio-based polyols 10 parts of tackifying resin 0.1 parts of the first catalyst 15 parts of filler.

[0029] Secondly, this embodiment provides a method for preparing a highly adhesive bio-based polyurethane hot melt adhesive, comprising the following steps: S1: Add 2.5 kg PPG1000, 12.5 kg self-made epoxidized castor oil polyol, 7.5 kg poly(phthalic anhydride-diethylene glycol diol), 5.0 kg poly(3-methyl-1,5-pentanediol sebacic acid) diol, 5.0 kg bio-based diol PTMG, 5.0 kg rosin resin, and 0.05 kg DABCO® MB125 to a reactor, heat to 120~130℃, vacuum dehydrate for 2 hours, and then add 7.5 kg hydroxymethylated lignin for dispersion; S2: Then dehydrate under vacuum at 120~130℃ for 1.5h; cool down to 100℃, add 4.8kg of diphenylmethane diisocyanate (MDI), control the R value of the colloid at 1.34, then heat to 110~115℃, react under vacuum of -0.1MPa for 2h, then turn off the stirring and discharge the material to obtain a high-adhesion bio-based polyurethane hot melt adhesive, which can be stored in vacuum or nitrogen-protected packaging.

[0030] Example 4 In a first aspect, this embodiment provides a highly adhesive bio-based polyurethane hot melt adhesive, the raw materials of which include the following components by weight: 10.5 parts isocyanate 5 parts polyether diol 12.3 parts of poly(phthalic anhydride-diethylene glycol) diol Epoxidized castor oil polyols, 25.7 parts 10.3 parts of tackifying resin 0.1 parts of the first catalyst 15.5 parts of filler.

[0031] Secondly, this embodiment provides a method for preparing a highly adhesive bio-based polyurethane hot melt adhesive, comprising the following steps: S1: Add 2.5kg PEG1000, 12.5kg self-made epoxidized castor oil polyol, 6.0kg poly(phthalic anhydride-diethylene glycol diol), 10.0kg self-made high initial tack, high adhesion bio-based diol, 5.0kg rosin resin, and 0.05kg DABCO® MB35 to a reactor, heat to 120~130℃, vacuum dehydrate for 2 hours, and then add 7.5kg epoxidized lignin for dispersion; S2: Then dehydrate under vacuum at 120~130℃ for 1.5h; cool down to 100℃, add 5.1kg of diphenylmethane diisocyanate (MDI), control the R value of the colloid at 1.26, then heat to 110~115℃, react under vacuum of -0.1MPa for 2h, then turn off the stirring and discharge the material to obtain a high-adhesion bio-based polyurethane hot melt adhesive, which can be stored in vacuum or nitrogen-protected packaging.

[0032] Example 5 In a first aspect, this embodiment provides a highly adhesive bio-based polyurethane hot melt adhesive, the raw materials of which include the following components by weight: 11.2 parts isocyanate 6.1 parts of polyether diol 10.2 parts of poly(phthalic anhydride-diethylene glycol) diol 10.2 parts of poly(3-methyl-1,5-pentanediol sebacate) diol Epoxidized castor oil polyols, 27.5 parts 12.2 parts of tackifying resin 0.1 parts of the first catalyst 12.2 parts of filler.

[0033] Secondly, this embodiment provides a method for preparing a highly adhesive bio-based polyurethane hot melt adhesive, comprising the following steps: S1: Add 3.0 kg PPG400, 13.5 kg self-made epoxidized castor oil polyol, 5.0 kg poly(phthalic anhydride-diethylene glycol diol), 5.0 kg poly(3-methyl-1,5-pentanediol sebacic acid), 5.0 kg self-made high initial tack, high adhesion bio-based diol, 6.0 kg petroleum resin, and 0.05 kg DABCO® MB20 to a reactor, heat to 120~130℃, vacuum dehydrate for 2 hours, and then add 6.0 kg hydroxymethylated lignin for dispersion; S2: Then dehydrate under vacuum at 120~130℃ for 1.5h; cool down to 100℃, add 5.5kg of diphenylmethane diisocyanate (MDI), control the R value of the colloid at 1.38, then heat to 110~115℃, react under vacuum of -0.1MPa for 2h, then turn off the stirring and discharge the material to obtain a high-adhesion bio-based polyurethane hot melt adhesive, which can be stored in vacuum or nitrogen-protected packaging.

[0034] Example 6 In a first aspect, this embodiment provides a high-adhesion bio-based polyurethane hot melt adhesive and its preparation method. The raw materials for preparation include the following components by weight: 11.4 parts isocyanate 5 parts of polyether diol 10.2 parts of poly(phthalic anhydride-diethylene glycol) diol Epoxidized castor oil polyols, 27.5 parts 10.2 parts of tackifying resin 0.1 parts of the first catalyst 15.3 parts of filler.

[0035] Secondly, this embodiment provides a method for preparing a highly adhesive bio-based polyurethane hot melt adhesive, comprising the following steps: S1: Add 2.5 kg PEG1000, 13.5 kg self-made epoxidized castor oil polyol, 5.0 kg poly(phthalic anhydride-diethylene glycol diol), a bio-based polyol composed of 5.0 kg self-made high initial tack, high adhesion bio-based diol and 5.0 kg bio-based diol PTMG, 5.0 kg rosin resin, and 0.05 kg DABCO® MB125 to a reactor, heat to 120~130℃, vacuum dehydrate for 2 hours, and then add 7.5 kg hydroxymethylated lignin for dispersion; S2: Then dehydrate under vacuum at 120~130℃ for 1.5h; cool down to 100℃, add 5.6kg of diphenylmethane diisocyanate (MDI), control the R value of the colloid at 1.43, then heat to 110~115℃, react under vacuum of -0.1MPa for 2h, then turn off the stirring, discharge the material to obtain a high-adhesion bio-based polyurethane hot melt adhesive, which is then stored in vacuum or nitrogen-protected packaging.

[0036] Comparative Example 1 Firstly, this comparative example provides a high-adhesion bio-based polyurethane hot melt adhesive and its preparation method. The raw materials for preparation include the following components by weight: 9 parts of isocyanate 22 parts of polyether diol 42 parts of poly(phthalic anhydride-diethylene glycol) diol 12 parts of epoxidized castor oil polyol 4.9 parts of tackifying resin 0.1 parts catalyst 10 parts of filler.

[0037] Secondly, this comparative example provides a method for preparing a highly adhesive bio-based polyurethane hot melt adhesive, comprising the following steps: S1: Add 11.0 kg PPG1000, 21 kg poly(phthalic anhydride-diethylene glycol) diol, 6.0 kg epoxidized castor oil polyol, 2.45 kg rosin resin, and 0.05 kg dibutyltin dilaurate into a reactor, heat to 120~130℃, dehydrate under vacuum for 2 hours, and then add 5 kg hydroxymethyl lignin for dispersion; S2: Then dehydrate under vacuum at 120~130℃ for 1.5h; cool down to 100℃, add 4.5kg of diphenylmethane diisocyanate (MDI), control the R value of the colloid at 1.15, then heat to 110~115℃, react under vacuum of -0.1MPa for 2h, then turn off the stirring, discharge the material to obtain a high-adhesion bio-based polyurethane hot melt adhesive, which is then stored in vacuum or nitrogen-protected packaging.

[0038] Performance tests were conducted on the high-adhesion bio-based polyurethane hot melt adhesive prepared in Application Examples 1-6 and Comparative Example 1, as well as competing products (adhesion test: the test substrate was a particleboard, and the edge banding strip was a 1mm PVC edge banding strip; aging test: the adhesive was baked at 150℃ for 5 hours, and the changes in viscosity and state of the adhesive were tracked, Brookfield CAP2000+@140℃). The results are shown in Table 1.

[0039] Table 1. Comparison of performance test results of Examples 1-6 and Comparative Example 1 with competing products. As can be seen from Table 1: 1. Regarding initial tack (out-of-machine strength) at 40°C, all examples and comparative examples were superior to or on par with the competing product (32N). Among them, Example 5 achieved 45N, demonstrating the best performance and excellent initial tack properties.

[0040] 2. In the critical 24-hour peel strength (5°C) test, Example 5 significantly outperformed the competitor (86N) and all other examples and comparative examples with a strength of 118N, demonstrating its superior long-term adhesion at low temperatures.

[0041] 3. Regarding stability (indicating viscosity growth rate and colloidal flowability after 5 hours of baking), the competing product showed a 100% viscosity increase and decreased flowability, while all examples demonstrated better stability, with viscosity growth controlled between 45% and 68% and good flowability. In contrast, the comparative example showed an 80% viscosity increase and poor colloidal flowability. Example 5 showed a 68% viscosity growth rate, which, while not the lowest, exhibited good colloidal flowability and overall stability, fully meeting the usage requirements.

[0042] In summary, compared with colloids prepared from petrochemical polyesters and competing products, Example 5 exhibits the best overall performance. It not only possesses the highest 24-hour peel strength (118N) and outstanding initial tack, but also demonstrates good stability and working condition. Furthermore, this embodiment has a bio-based content exceeding 60%, combining excellent performance with environmentally friendly characteristics.

[0043] This invention provides a high-adhesion bio-based polyurethane hot melt adhesive and its preparation method, whose performance meets customer requirements. It effectively reduces the use of petroleum-based raw materials and introduces bio-based raw materials, providing effective support for renewable and degradable materials. The demand for bio-based degradable materials is increasing daily, and the bio-based degradable PUR edge-sealing adhesive of this invention not only has advantages such as good high-temperature adhesion and high final bond strength, but also is degradable, meeting environmental protection requirements, and therefore has broad application prospects in the market. At the same time, the preparation method of this invention is simple and low-cost, which is conducive to large-scale industrial production, meeting the market demand for efficient, environmentally friendly, and low-cost polymer materials and adhesives.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A highly adhesive bio-based polyurethane hot melt adhesive, characterized in that, The raw materials for preparation include the following components by weight: 10-30 parts of isocyanate 5-20 parts of polyether diol 10-40 parts of poly(phthalic anhydride-diethylene glycol) diol 10-40 parts of poly(3-methyl-1,5-pentanediol sebacate) 15-40 parts of bio-based polyols 10-20 parts of tackifying resin 0.05~0.5 parts of the first catalyst 10-20 parts of filler.

2. The high-adhesion bio-based polyurethane hot melt adhesive according to claim 1, characterized in that, The isocyanate contains 0.9-2.5% free isocyanate groups by mass, and the isocyanate is composed of one or more of diphenylmethane-4,4-diisocyanate and 4,4-dicyclohexylmethane diisocyanate mixed in any proportion.

3. The high-adhesion bio-based polyurethane hot melt adhesive according to claim 1, characterized in that, The hydroxyl value of the poly(phthalic anhydride-diethylene glycol diol), poly(3-methyl-1,5-pentanediol sebacic acid) diol, and the bio-based polyol is 18~60 mgKOH / g, and the acid value is 0.1~2 mgKOH / g.

4. The highly adhesive bio-based polyurethane hot melt adhesive according to claim 1, characterized in that, The polyether diol is composed of one or more of PPG400, PPG1000, PEG400, and PEG1000 mixed in any proportion.

5. The highly adhesive bio-based polyurethane hot melt adhesive according to claim 1, characterized in that, The bio-based polyol is composed of one or more of the following: epoxidized castor oil polyol, castor oil, bio-based diol PTMG, and self-made high initial tack and high adhesion bio-based diol, mixed in any proportion; the self-made high initial tack and high adhesion bio-based diol is prepared by the following method: 2,5-furandicarboxylic acid, succinic acid, 1,4-butanediol, 1,3-propanediol and terephthalic acid were mixed in a molar ratio of 0.7~0.9:0.2~0.4:1.0:0.1~0.2:0.1~0.3, and a second catalyst of 0.1%~0.5% of the total mass of the reactants was added to carry out an esterification polycondensation reaction to obtain a self-made bio-based diol with high initial viscosity and high adhesion of terephthalic acid. The second catalyst is composed of one or more of tetrabutyl titanate, zinc acetate, or antimony oxide mixed in any proportion; the esterification polycondensation reaction is carried out under inert gas protection, at a reaction temperature of 180~240℃, a reaction pressure of 0.1~0.5MPa, and a reaction time of 4~10 hours.

6. The high-adhesion bio-based polyurethane hot melt adhesive according to claim 1, characterized in that, The tackifying resin is composed of one or more of Covestro Desmopan® TPU 3695AU, petroleum resin, and rosin resin in any proportion.

7. The highly adhesive bio-based polyurethane hot melt adhesive according to claim 1, characterized in that, The filler is composed of one or more of hydroxymethylated lignin, epoxidized lignin, and fumed silica in any proportion.

8. The high-adhesion bio-based polyurethane hot melt adhesive according to claim 1, characterized in that, The first catalyst is composed of one or more of DABCO® MB20, DABCO® MB35, and DABCO® MB125 mixed in any proportion.

9. The highly adhesive bio-based polyurethane hot melt adhesive according to claim 1, characterized in that, The epoxidized castor oil polyol was prepared by the following steps: (1) Mix castor oil with formic acid or acetic acid in a 1:1 molar ratio, and then slowly add an oxidant while stirring. React at 20-60°C for 2-6 hours to obtain epoxidized castor oil. The oxidant is composed of one or more of peroxyformic acid, peroxyacetic acid or hydrogen peroxide with a volume concentration of 30%-50% in any proportion. (2) The epoxidized castor oil obtained in step (1) is mixed with the ring-opening agent at a molar ratio of 1:3, and sulfuric acid with a mass concentration of 98% is added. The mixture is reacted at 40-80℃ for 2-5 hours to obtain an intermediate product. The ring-opening agent is methanol or ethylene glycol, and the amount of sulfuric acid added is 0.5%-5% of the total mass of the reaction system. (3) Neutralize, wash with water and dry the intermediate product of step (2) to obtain epoxidized castor oil polyol.

10. A method for preparing the high-adhesion bio-based polyurethane hot melt adhesive as described in claim 1, characterized in that, Includes the following steps: S1: Add 5-20 parts by weight of polyether diol, 5-40 parts by weight of self-made epoxidized castor oil polyol, 10-40 parts by weight of polyphthalic anhydride-diethylene glycol diol, 15-40 parts by weight of bio-based polyol, 10-20 parts by weight of tackifying resin, and 0.05-0.5 parts by weight of the first catalyst into the reactor. After heating to 100-150℃ and vacuum dehydrating for 2 hours, add 10-20 parts by weight of filler for dispersion. S2: Then, vacuum dehydrate at 120~140℃ for 2 hours, cool down to 90~110℃ and add 10~30 parts by weight of isocyanate, control the R value of the colloid to be 0.9~1.5, and then react at 110~120℃ and vacuum degree of -0.098 ~ -0.1MPa for 2 hours before discharging to obtain a high-adhesion bio-based polyurethane hot melt adhesive.

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