Bio-based reusable light / moisture dual-curing polyurethane hot melt adhesive and preparation method thereof

Abstract

The invention provides a bio-based reusable light / moisture dual-curing polyurethane hot melt adhesive, which is characterized in that a novel bio-based modifier is synthesized through reaction of bio-based mustard oil and 2, 2 '-dithio-diyl diethylamine, and the bio-based modifier has a double bond, a dynamic disulfide bond and a thiourea bond which can be photo-cured, so that the light / moisture dual-curing polyurethane hot melt adhesive has the advantages that the light / moisture dual-curing polyurethane hot melt adhesive can be used for preparing the light / moisture dual-curing polyurethane hot melt adhesive, and the service life of the light / moisture dual-curing polyurethane hot melt adhesive is prolonged; the hot melt adhesive prepared by adopting the modifier not only has the characteristics of short curing time and high initial adhesion strength, but also has reusability, water resistance and heat resistance, belongs to a high-performance and environment-friendly hot melt adhesive, and has a great application prospect in the fields of electronic devices, precious metals and the like which need to be disassembled and recycled.

Description

Technical Field

[0001] The invention belongs to the field of polyurethane hot melt adhesives, and in particular relates to a bio-based reusable light / moisture dual-curing polyurethane hot melt adhesive and a preparation method thereof. Background Art

[0002] Polyurethane hot melt adhesive plays an important role in many industries due to its solvent-free and high-performance characteristics. Polyurethane hot melt adhesive has excellent bonding properties to a variety of materials, including metals, plastics and wood, and can remain stable over a wide temperature range, showing excellent temperature resistance, chemical resistance and aging resistance.

[0003] Traditional polyurethane hot melt adhesives are mainly cured by moisture. After application, moisture in the air reacts with isocyanate groups to achieve curing. However, moisture in the air penetrates slowly, resulting in a long curing time and low initial adhesion strength. At the same time, long-term pressure maintenance is required to achieve the final bonding effect, which reduces production efficiency. At the same time, polyurethane hot melt adhesives are thermosetting materials. Once they react with moisture in the air or substrate to form a cross-linked structure, they are almost impossible to reprocess or remove from the substrate. Once the material is damaged, it can only be replaced, resulting in a huge waste of resources. In addition, most polyurethane raw materials and additives come from non-renewable resources.

[0004] Therefore, it is necessary to develop a new type of green and environmentally friendly polyurethane hot melt adhesive with short curing time, high initial bonding strength, and detachable and reusable properties to meet the needs of current social development. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a bio-based reusable light / wet dual-curing polyurethane hot melt adhesive, which uses renewable and low-cost natural materials as raw materials to synthesize a new type of mustard oil bio-based modifier, which introduces a photocurable double bond to make the system have the performance of light curing on the basis of the original moisture curing, thereby realizing light / wet dual curing. In the curing process, first, after ultraviolet light irradiation, the molecular part is cross-linked to increase the viscosity, achieve rapid positioning, and improve the initial adhesion strength; in the wet curing stage, the isocyanate group is used to react with the moisture in the air to further cross-link the molecular chains, so as to achieve complete curing and obtain the final high bonding strength. In addition, the new bio-based modifier provided by the present invention also introduces dynamic disulfide bonds and thiourea bonds at the same time. Based on the thermal reversibility of dynamic disulfide bonds and thiourea bonds, under certain conditions, the polyurethane hot melt adhesive has detachable and reusable properties, which prolongs the service life of the material, so that it has great application prospects in the fields of electronic devices and precious metals that need to be disassembled and recycled. The polyurethane hot melt adhesive of the present invention can also improve the cohesion of the adhesive by introducing hydrogen bonds formed by thiourea bonds through the bio-based modifier, making the adhesive less likely to be destroyed when subjected to external force, thereby further strengthening the bonding effect. In addition, the introduction of thiourea bonds improves the water resistance and heat resistance of the adhesive.

[0006] The above-mentioned object of the present invention is mainly achieved through the following technical scheme: a bio-based reusable light / moisture dual-curing polyurethane hot melt adhesive, the raw material composition and weight ratio of which are: 25-49 parts of polyester polyol, 20-40 parts of polyether polyol, 21-26 parts of polyisocyanate, 1.5-3.5 parts of bio-based modifier, 1-2 parts of low molecular weight saturated diol, 0.05-0.1 parts of catalyst, 1-2 parts of photoinitiator, 0.5-1 parts of silane coupling agent, and 1-1.5 parts of antioxidant; wherein the bio-based modifier is a compound containing dynamic disulfide bonds, thiourea bonds in the molecular chain and double bonds and amino groups at the chain end, and its structure is shown as follows:

[0007]

[0008] The preparation method of the bio-based modifier comprises the following steps: under the protection of inert gas, bio-based mustard oil and dehydrated 2,2'-dithiodiethylamine are reacted at a mass ratio of (0.68-0.87):1 at room temperature for 2 hours, and after the reaction is completed, the bio-based modifier is sealed and stored to obtain the bio-based modifier.

[0009] Furthermore, the bio-based mustard oil is refined mustard oil, containing more than 90% of the main component allyl isothiocyanate.

[0010] Furthermore, the polyester polyol is one of polybutylene adipate and polycaprolactone polyol with a molecular weight of 1000-2000; the polyether polyol is a polyether polyol with a molecular weight of 1000-2000, one or more of polyether triol, polyethylene glycol, polytetramethylene ether glycol, and polyoxypropylene glycol; the polyisocyanate is one or more of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate; the low molecular weight saturated diol is one or more of ethylene glycol, 1,4-cyclohexanediol, 1,4-butanediol, 1,2-pentanediol, 1,5-pentanediol, 1,6-hexanediol, and 1,3-butanediol.

[0011] Furthermore, the catalyst is one of dibutyltin dilaurate, stannous octoate and stannous chloride.

[0012] Furthermore, the photoinitiator is one or more of 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methylpropiophenone, 4-methylbenzophenone, and 4-phenylbenzophenone.

[0013] Furthermore, the silane coupling agent is one of KH-560, KH-570 and KH-550.

[0014] Furthermore, the antioxidant is one or more of 2,6-di-tert-butyl-p-methylphenol, antioxidant 1010, and antioxidant 168.

[0015] Furthermore, the preparation method of the bio-based reusable light / moisture dual-curing polyurethane hot melt adhesive comprises the following steps:

[0016] (1) Add polyester polyol and polyether polyol into a reaction vessel, heat and stir evenly, remove water in vacuum at 100° C. for 2 h, and then cool to 60° C. under nitrogen protection;

[0017] (2) adding polyisocyanate and organotin catalyst into a reaction vessel under nitrogen protection, reacting at 80° C. under nitrogen protection for 2 h, degassing for 30 min, and then cooling to 60° C. under nitrogen protection;

[0018] (3) adding a low molecular weight saturated diol into the reactor, reacting at 80° C. under nitrogen protection for 1 h, and then cooling to 25° C. under nitrogen protection;

[0019] (4) adding a bio-based modifier and a photoinitiator into the reactor, reacting for 1 hour under nitrogen protection; adding a coupling agent and an antioxidant, continuing to react for 1 hour at 25° C. under nitrogen protection, degassing for 30-50 minutes, then discharging the material and sealing it for storage, thereby obtaining a bio-based reusable light / moisture dual-curing polyurethane hot melt adhesive.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. Compared with single light-curing adhesive, the light / moisture dual-curing polyurethane hot melt adhesive of the present invention has higher final adhesive strength, can meet more application places, and has stronger adhesion to the substrate; compared with the traditional moisture-curing polyurethane hot melt adhesive, due to the introduction of light-curable double bonds at the chain end, the adhesive can have higher initial adhesive strength, achieve rapid positioning, shorten the curing time, and after moisture curing, due to the formation of a tight cross-linking structure, the final adhesive strength is also better.

[0022] 2. The polyurethane hot melt adhesive of the present invention utilizes a bio-based multifunctional modifier to introduce not only double bonds of photocurable groups, but also dynamic disulfide bonds and thiourea bonds. Based on the thermal reversibility of the dynamic disulfide bonds and thiourea bonds, the introduction of dynamic disulfide bonds and thiourea bonds enables the polyurethane hot melt adhesive to have the functions of detachability and reusability, which is very critical for handling the precious electronic components and devices to be bonded and extending the service life of the materials. In addition, the bonding strength of the polyurethane hot melt adhesive after cyclic bonding is still very high, and it has good reusability characteristics.

[0023] 3. The raw material mustard oil used in the bio-based modifier introduced into the polyurethane hot melt adhesive of the present invention is a natural product, a renewable resource, environmentally friendly, and reduces the carbon footprint. Compared with the commonly used acrylic photocuring system, it avoids the problems of acrylic monomers such as high allergenicity, strong odor, and environmental pollution.

[0024] 4. The polyurethane hot melt adhesive of the present invention introduces thiourea bonds through bio-based modifiers, which not only makes the adhesive reusable, but also the hydrogen bonds formed by the thiourea bonds increase the cohesive force of the adhesive, making the adhesive less likely to be damaged when subjected to external forces, thereby further strengthening the bonding effect. The introduction of thiourea bonds also improves the water resistance and heat resistance of the adhesive.

[0025] 5. The polyurethane hot melt adhesive prepared by the present invention has multiple excellent properties by introducing a bio-based modifier. It not only has high initial adhesion strength, but also has the properties of being detachable and reusable. At the same time, the water resistance and heat resistance of the polyurethane hot melt adhesive are improved. It has great application prospects in fields such as electronic devices and precious metals that need to be disassembled and recycled. DETAILED DESCRIPTION

[0026] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0027] Example 1

[0028] Preparation of bio-based modifier: Weigh 38.27 g of refined mustard oil, slowly add 50.77 g of dehydrated 2,2'-dithiodiethylamine into the mustard oil, and stir the reaction at room temperature for 2 hours under a nitrogen atmosphere. After the reaction is completed, seal and store to obtain a bio-based modifier.

[0029] Preparation of light / moisture dual-curing polyurethane hot melt adhesive: Weigh 60g of polybutylene adipate (molecular weight 2000g / mol) and 40g of polyoxypropylene glycol (molecular weight 1000g / mol) and add them into a four-necked bottle, start timing when the temperature reaches 100°C and the vacuum degree reaches -0.09MPa, vacuum dehydrate for 2h, then cool to 60°C, add 35g of diphenylmethane diisocyanate and 1.21g of dibutyltin dilaurate, react at 80°C for 2h, degasse for 0.5h and cool. When the temperature drops to 60°C, add 2.19 g of 1,4-butanediol. When the temperature reaches 80°C, react for 1 hour. When the temperature drops to 25°C, add 3.54 g of the above-prepared bio-based modifier and 2.10 g of 2-hydroxy-2-methylpropiophenone. After reacting for 1 hour, add 1.34 g of KH-560 and 2.01 g of antioxidant 1010. Continue to react for 1 hour. Degassing treatment is performed for 30-50 minutes. The material is discharged and sealed for storage to obtain a bio-based reusable light / moisture dual-curing polyurethane hot melt adhesive 1.

[0030] Example 2

[0031] Preparation of bio-based modifier: Weigh 38.27 g of refined mustard oil, slowly add 50.77 g of dehydrated 2,2'-dithiodiethylamine into the mustard oil, and stir the reaction at room temperature for 2 hours under a nitrogen atmosphere. After the reaction is completed, seal and store to obtain a bio-based modifier.

[0032] Preparation of light / moisture dual-curing polyurethane hot melt adhesive: Weigh 70g of polybutylene adipate (molecular weight 2000g / mol) and 30g of polyoxypropylene glycol (molecular weight 1000g / mol) and add them into a four-necked bottle, start timing when the temperature reaches 100°C and the vacuum degree reaches -0.09MPa, vacuum dehydrate for 2h, then cool to 60°C, add 32.5g of diphenylmethane diisocyanate and 1.19g of dibutyltin dilaurate, react at 80°C for 2h, degas for 0.5h and cool. When the temperature drops to 60°C, add 1.83g of 1,4-butanediol. When the temperature reaches 80°C, react for 1h. Then, when the temperature drops to 25°C, add 4.31g of the above-prepared bio-based modifier and 2.07g of 2-hydroxy-2-methylpropiophenone. After reacting for 1h, add 1.32g of KH-560 and 1.98g of antioxidant 1010. Continue to react for 1h. Degassing treatment is performed for 30-50min. The material is discharged and sealed for storage to obtain a bio-based reusable light / moisture dual-curing polyurethane hot melt adhesive 2.

[0033] Example 3

[0034] Preparation of bio-based modifier: Weigh 34.80 g of refined mustard oil, slowly add 50.77 g of dehydrated 2,2'-dithiodiethylamine into the mustard oil, and stir the reaction at room temperature for 2 h under a nitrogen atmosphere. After the reaction is completed, seal and store to obtain a bio-based modifier.

[0035] Preparation of light / moisture dual-curing polyurethane hot melt adhesive: Weigh 60g of polybutylene adipate (molecular weight 2000g / mol) and 40g of polyoxypropylene glycol (molecular weight 1000g / mol) and add them into a four-necked bottle, start timing when the temperature reaches 100°C and the vacuum degree reaches -0.09MPa, vacuum dehydrate for 2h, then cool to 60°C, add 35g of diphenylmethane diisocyanate and 1.21g of dibutyltin dilaurate, react at 80°C for 2h, degasse for 0.5h and cool. When the temperature drops to 60°C, add 2.19 g of 1,4-butanediol. When the temperature reaches 80°C, react for 1 hour. When the temperature drops to 25°C, add 3.54 g of the above-prepared bio-based modifier and 2.10 g of 2-hydroxy-2-methylpropiophenone. After reacting for 1 hour, add 1.34 g of KH-560 and 2.01 g of antioxidant 1010. Continue to react for 1 hour. Degassing treatment is performed for 30-50 minutes. The material is discharged and sealed for storage to obtain a bio-based reusable light / moisture dual-curing polyurethane hot melt adhesive 3.

[0036] Example 4

[0037] Preparation of bio-based modifier: Weigh 34.80 g of refined mustard oil, slowly add 50.77 g of dehydrated 2,2'-dithiodiethylamine into the mustard oil, and stir the reaction at room temperature for 2 h under a nitrogen atmosphere. After the reaction is completed, seal and store to obtain a bio-based modifier.

[0038] Preparation of light / moisture dual-curing polyurethane hot melt adhesive: Weigh 70g of polybutylene adipate (molecular weight 2000g / mol) and 30g of polyoxypropylene glycol (molecular weight 1000g / mol) and add them into a four-necked bottle, start timing when the temperature reaches 100°C and the vacuum degree reaches -0.09MPa, vacuum dehydrate for 2h, then cool to 60°C, add 32.5g of diphenylmethane diisocyanate and 1.19g of dibutyltin dilaurate, react at 80°C for 2h, degas for 0.5h and cool. When the temperature drops to 60°C, add 1.83g of 1,4-butanediol. When the temperature reaches 80°C, react for 1h. Then, when the temperature drops to 25°C, add 4.31g of the above-prepared bio-based modifier and 2.07g of 2-hydroxy-2-methylpropiophenone. After reacting for 1h, add 1.32g of KH-560 and 1.98g of antioxidant 1010. Continue to react for 1h. Degassing treatment is performed for 30-50min. The material is discharged and sealed for storage to obtain a bio-based reusable light / moisture dual-curing polyurethane hot melt adhesive 4.

[0039] Comparative Example 1

[0040] Preparation of single moisture-cured polyurethane hot melt adhesive: weigh 70g of polybutylene adipate (molecular weight 2000g / mol) and 30g of polyoxypropylene glycol (molecular weight 1000g / mol) and add them to a four-necked bottle. Start timing when the temperature reaches 100°C and the vacuum reaches -0.09MPa. Vacuum dehydration for 2h, then cool to 60°C, add 32.5g of diphenylmethane diisocyanate and 1.19g of dibutyltin dilaurate. When the temperature reaches 80°C, react for 2h, degassing for 0.5h and cooling. When the temperature drops to 60°C, add 2.16g of 1,4-butanediol. When the temperature reaches 80°C, add 1.32g of KH-560 and 1.98g of antioxidant 1010 after 1h of reaction. Continue to react for 1h, degassing for 30-50min, discharge and seal to obtain moisture-cured polyurethane hot melt adhesive.

[0041] Comparative Example 2

[0042] Preparation of acrylic light / moisture dual-curing polyurethane hot melt adhesive: Weigh 70g of polybutylene adipate (molecular weight 2000g / mol) and 30g of polyoxypropylene glycol (molecular weight 1000g / mol) and add them into a four-necked bottle, start timing when the temperature reaches 100°C and the vacuum degree reaches -0.09MPa, vacuum dehydrate for 2h, then cool to 60°C, add 32.5g of diphenylmethane diisocyanate and 1.19g of dibutyltin dilaurate, react at 80°C for 2h, degas for 0.5h and cool. When the temperature drops to 60°C, add 1.83g of 1,4-butanediol. When the temperature reaches 80°C, react for 1h, then add 2.18g of hydroxyethyl acrylate and 2.07g of 2-hydroxy-2-methylpropiophenone. After reacting for 1h, add 1.32g of KH-560 and 1.98g of antioxidant 1010, continue to react for 1h, degas for 30-50min, discharge the material and seal it for storage to obtain acrylic light / moisture dual-curing polyurethane hot melt adhesive.

[0043] Performance Testing:

[0044] The polyurethane hot melt adhesives of Examples 1-4 and Comparative Example 2 were placed in a dispensing machine sleeve and heated at 120°C. The adhesive layer was dispensed on a PC board for shear strength testing with a thickness of 0.1mm, and then pressed with a 1KG weight for 10 minutes. After irradiation with a UV lamp for 60 seconds, the adhesive was placed under standard conditions (25°C, 50% RH), maintained under pressure for 20 minutes, and the 1KG weight was removed. The shear strength at different curing times was tested according to the GB / T7124-2008 test method. The 30-minute shear strength after light curing is the initial adhesive strength, and the shear strength after complete curing is the final adhesive strength.

[0045] The polyurethane hot melt adhesive dispensing machine of the comparative example 1 was heated in the sleeve, the temperature in the sleeve was 120°C, and the adhesive was dispensed on the PC board for shear strength testing, the adhesive layer thickness was 0.1mm, and then pressed with a 1KG weight, placed under standard conditions (25°C, 50% RH) for curing, and the shear strength at different curing times was tested respectively according to the GB / T7124-2008 test method. The shear strength after 30 minutes of glue application and pressing is the initial adhesive strength, and the shear strength after complete curing is the final adhesive strength.

[0046] The polyurethane hot melt adhesives of Examples 1-4 and Comparative Examples 1-2 were tested for their detachability. The fully cured PC board was placed in an oven at 120°C and heated for 1 hour, and the residual adhesive on the substrate was scraped off while it was still hot. The removal rate of the residual adhesive (η) was calculated by the formula:

[0047]

[0048] Among them, m 0 represents the mass of the substrate, and m1 and m 2 They represent the quality of the substrate after applying the glue and after the removal of the residual glue.

[0049] The polyurethane hot melt adhesives of Examples 1-4 and Comparative Examples 1-2 were subjected to a reusability test. The fully cured polyurethane hot melt adhesive film was sandwiched between two PC substrates with a clip, and then placed in an oven at 120°C to melt the hot melt adhesive and bond the substrates. The substrates were then cooled down to room temperature, and after being fully cured, their shear strength was measured as the bonding strength of the polyurethane hot melt adhesive after recycling. Finally, repeated experiments of destruction and repair bonding were performed multiple times to evaluate the reusability of the polyurethane hot melt adhesives of the above Examples and Comparative Examples.

[0050] Table 1: Performance test results of examples and comparative examples

[0051]

[0052] As can be seen from Table 1, compared with Comparative Example 1, the urethane hot melt adhesive of the present invention has higher initial adhesion strength and final adhesion strength than Comparative Example 1 of the existing single moisture curing system due to the introduction of a multi-functional bio-based modifier, and has a shorter curing time, better disassembly and reusability. Comparative Example 1 cannot be bonded after one cycle of destruction under the same post-destruction conditions, and the residual adhesive removal rate is only 20%.

[0053] Compared with the existing acrylic light / moisture dual-curing polyurethane hot melt adhesive comparative example 2, the initial adhesion strength, final adhesion strength and complete curing time of the present invention are not much different, but the shear strength of comparative example 2 is reduced by 65% ​​under the same post-destruction conditions, the residual adhesive removal rate is 60%, the disassembly and reusability are poor, and the introduction of acrylic acid will cause environmental problems such as irritating odor.

[0054] In summary, the present invention uses a new type of bio-based modifier to simultaneously introduce photocurable double bonds, dynamic disulfide bonds and thiourea bonds, and the prepared hot melt adhesive not only has the characteristics of short curing time and high initial adhesion strength, but also has reusability, water resistance and heat resistance. It has great application prospects in fields such as electronic devices and precious metals that need to be disassembled and recycled.

[0055] 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 principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A bio-based reusable light / moisture dual-curing polyurethane hot melt adhesive, characterized in that: The raw material composition and weight ratio of the polyurethane hot melt adhesive are as follows: 25-49 parts of polyester polyol, 20-40 parts of polyether polyol, 21-26 parts of polyisocyanate, 1.5-3.5 parts of bio-based modifier, 1-2 parts of low molecular weight saturated diol, 0.05-0.1 parts of catalyst, 1-2 parts of photoinitiator, 0.5-1 parts of silane coupling agent, and 1-1.5 parts of antioxidant; wherein the bio-based modifier is a compound containing dynamic disulfide bonds, thiourea bonds in the molecular chain, and double bonds and amino groups at the chain ends, and its structure is shown as follows: The preparation method of the bio-based modifier comprises the following steps: under the protection of inert gas, bio-based mustard oil and dehydrated 2,2'-dithiodiethylamine are reacted at a mass ratio of (0.68-0.87):1 at room temperature for 2 hours, and after the reaction is completed, the bio-based modifier is sealed and stored to obtain the bio-based modifier.

2. The bio-based reusable light / moisture dual-curing polyurethane hot melt adhesive according to claim 1, characterized in that: The bio-based mustard oil is refined mustard oil, containing more than 90% of the main component allyl isothiocyanate.

3. The bio-based reusable light / moisture dual-curing polyurethane hot melt adhesive according to claim 1, characterized in that: The polyester polyol is one of polybutylene adipate and polycaprolactone polyol with a molecular weight of 1000-2000; the polyether polyol is one or more of polyether triol, polyethylene glycol, polytetramethylene ether glycol and polyoxypropylene glycol with a molecular weight of 1000-2000; the polyisocyanate is one or more of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate; the low molecular weight saturated diol is one or more of ethylene glycol, 1,4-cyclohexanediol, 1,4-butanediol, 1,2-pentanediol, 1,5-pentanediol, 1,6-hexanediol and 1,3-butanediol.

4. The bio-based reusable light / moisture dual-curing polyurethane hot melt adhesive according to claim 1, characterized in that: The catalyst is one of dibutyltin dilaurate, stannous octoate and stannous chloride.

5. The bio-based reusable light / moisture dual-curing polyurethane hot melt adhesive according to claim 1, characterized in that: The photoinitiator is one or more of 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methylpropiophenone, 4-methylbenzophenone and 4-phenylbenzophenone.

6. The bio-based reusable light / moisture dual-curing polyurethane hot melt adhesive according to claim 1, characterized in that: The silane coupling agent is one of KH-560, KH-570 and KH-550.

7. The bio-based reusable light / moisture dual-curing polyurethane hot melt adhesive according to claim 1, characterized in that: The antioxidant is one or more of 2,6-di-tert-butyl-p-methylphenol, antioxidant 1010, and antioxidant 168.

8. The bio-based reusable light / moisture dual-curing polyurethane hot melt adhesive according to claim 1, wherein the preparation method comprises the following steps: (1) Add polyester polyol and polyether polyol into a reaction vessel, heat and stir evenly, remove water in vacuum at 100° C. for 2 h, and then cool to 60° C. under nitrogen protection; (2) adding polyisocyanate and organotin catalyst into a reaction vessel under nitrogen protection, reacting at 80° C. under nitrogen protection for 2 h, degassing for 30 min, and then cooling to 60° C. under nitrogen protection; (3) adding a low molecular weight saturated diol into the reactor, reacting at 80° C. under nitrogen protection for 1 h, and then cooling to 25° C. under nitrogen protection; (4) adding a bio-based modifier and a photoinitiator into the reactor, reacting for 1 hour under nitrogen protection; adding a coupling agent and an antioxidant, continuing to react for 1 hour at 25° C. under nitrogen protection, degassing for 30-50 minutes, then discharging the material and sealing it for storage, thereby obtaining a bio-based reusable light / moisture dual-curing polyurethane hot melt adhesive.

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