Bio-based dual-curing adhesives and their preparation methods

Abstract

This invention belongs to the field of adhesive synthesis technology, specifically relating to a bio-based dual-curing adhesive and its preparation method. It is prepared from the following raw materials in parts by weight: 60-80 parts of UV / moisture dual-curing bio-based modified resin, 10-30 parts of acrylate reactive diluent monomer, 1-5 parts of adhesion promoter, 1-5 parts of photoinitiator, and 2-5 parts of thixotropic agent. The bio-based modified resin is prepared using phytol and castor oil as modifying raw materials, significantly improving the resin's flexibility and environmental compatibility. The UV / moisture dual-curing adhesive of this invention has good surface drying effect, strong adhesion, excellent hydrophobic properties, and is environmentally friendly. It also solves the defect of traditional UV adhesives that cannot cure in the absence of light, effectively broadening its application range.

Description

Technical Field

[0001] This invention belongs to the field of adhesive synthesis technology, specifically relating to bio-based dual-curing adhesives and their preparation methods. Background Technology

[0002] Ultraviolet (UV) light curing is a green and environmentally friendly technology that emerged in the 1970s. This technology primarily uses UV light to stimulate a photoinitiator within the system to generate free radicals or cations. These free radicals or cations then further initiate various polymerizations between unsaturated double bonds or epoxy groups and other functional groups, forming a cross-linked cured structure. Simultaneously, UV technology produces low VOC emissions during the curing process, and it offers fast curing speed, energy savings, and minimal environmental pollution, while producing cured films with excellent overall performance. It meets both environmental requirements and the needs of rapid industrial production lines, making it a promising adhesive curing method. However, its application on opaque materials, ultra-thick coatings, colored coatings, and complex-shaped substrates has always been relatively difficult, a major drawback of UV technology. That is, only areas exposed to UV light can cure, while areas not exposed to UV light are difficult to cure completely. This means that adhesives using a single UV curing method cannot meet the required standards. Adopting a UV / moisture dual curing method allows for secondary curing using moisture in the air, enhancing adhesion and effectively expanding the application range of UV curing technology.

[0003] With increasing global awareness of environmental protection and the promotion of sustainable development, UV / moisture dual-curing resins have a very broad market application prospect in the adhesive field. Patent CN112795366A provides a method for preparing a UV / moisture dual-curing polysiloxane sealant, which is obtained by an addition reaction of thiols and olefins. However, the odor of thiols is difficult to eliminate and can be harmful to the body, and the moisture reaction between thiols and vinyl groups is difficult to control, easily reducing the storage stability of the composition. Patent CN109705794A provides a low-viscosity UV / moisture dual-curing polyurethane hot melt adhesive and its preparation method, combining free radical photocuring, cationic photocuring, and moisture curing. However, cationic photocuring has a slow rate, and the cost of the initiator is high. Patent CN119684966A discloses a heat and moisture dual-curing silicone sealant and its preparation method. It is prepared from raw materials including hydroxyl-terminated methylvinyl polysiloxane and alkoxy-terminated polydimethylsiloxane. It allows for rapid positioning and curing, and after curing, exhibits high strength, good adhesion, excellent temperature resistance, and a long shelf life, making it suitable for various applications requiring rapid positioning and assembly. However, this system requires high-temperature pre-curing, therefore it cannot be used on substrates requiring low-temperature curing and good adhesion. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a bio-based dual-curing adhesive with features such as good surface drying effect, strong adhesion, excellent hydrophobic properties, and environmental friendliness.

[0005] The present invention also provides a preparation method, which is simple and has mild reaction conditions.

[0006] The bio-based dual-curing adhesive of the present invention comprises the following raw materials in parts by weight:

[0007] 60-80 parts of UV / moisture dual-curing bio-based modified resin;

[0008] 10-30 parts of acrylate reactive diluent monomer;

[0009] 1-5 parts of adhesion accelerator;

[0010] 1-5 parts of photoinitiator;

[0011] 2-5 parts of thixotropic agent;

[0012] The UV / moisture dual-curing bio-based modified resin is a modified polyurethane resin containing bio-based polyether polyol segments, phytol structural units, and silane coupling agent structural units.

[0013] The preparation of the UV / moisture dual-curing bio-based modified resin includes the following steps:

[0014] a. React bio-based polyether polyol and diisocyanate together to obtain a prepolymer;

[0015] b. The obtained prepolymer and phytol are mixed and reacted. After the reaction is completed, a modified silane coupling agent is added to react, thus obtaining a UV / moisture dual-curing bio-based modified resin.

[0016] The bio-based polyether polyol mentioned in step a is castor oil polyether polyol with a number average molecular weight of 1000~3000 g / mol; the diisocyanate mentioned in step a is one of isophorone diisocyanate, hexamethylene diisocyanate, and dicyclohexylmethane diisocyanate, and the molar ratio of the diisocyanate and the bio-based polyether polyol mentioned in step a is (2~2.1):1.

[0017] The molar ratio of the prepolymer to phytol in step b is 1:(1~1.1).

[0018] The molar ratio of the prepolymer to the modified silane coupling agent in step b is 1:(1~1.1).

[0019] The modified silane coupling agent in step b is obtained by reacting castor oil with isocyanate-based silane, wherein the isocyanate-based silane is one of 3-isocyanate-based propyltrimethoxysilane and 3-isocyanate-based propyltriethoxysilane, and the molar ratio of castor oil to isocyanate-based silane is 1:(1~2).

[0020] The acrylate reactive diluent monomer is 3-methacryloyloxypropyltrimethoxysilane.

[0021] The adhesion promoter is one or more of aminopropyltrimethoxysilane, N-aminoethyl-3-aminopropylmethyldimethoxysilane, N-aminoethyl-3-aminopropyltrimethoxysilane, and N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane.

[0022] The photoinitiator is one or more of the following: alkyl phenyl ketones, benzoyl ketones, acyl phosphate oxides, benzoyl ketones and their derivatives, benzoyl ketones, oxime esters, thioxanthones, aromatic iodonium salts, alkyl iodonium salts, and cumeneferrocene hexafluorophosphate.

[0023] The thixotropic agent is one of fumed silica and organobentonite.

[0024] The preparation method of the bio-based dual-curing adhesive of the present invention includes the following steps: adding UV / moisture dual-curing bio-based modified resin and acrylate reactive diluent monomer into a mixer, stirring at 800~1000 rpm for 0.5~1 hours under vacuum conditions of -0.1~-0.08 MPa; adding adhesion promoter, photoinitiator and thixotropic agent into the mixer, avoiding light, stirring at 800~1000 rpm for 0.5~1 hours under vacuum conditions of -0.1~-0.08 MPa, and then depressurizing with nitrogen to obtain the bio-based dual-curing adhesive.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1) This invention uses phytol, a bio-based material, to modify the prepolymer. The double bond structure of phytol is relatively stable, which ensures the smooth introduction of carbon-carbon double bonds into the resin structure to participate in the UV curing reaction. The aliphatic structure also gives the colloid better flow and adhesion, which is beneficial to the adhesion to the substrate. On the other end, by reacting with the modified silane coupling agent, siloxane groups are introduced, which can not only improve the mechanical properties of the cured product, but also participate in moisture curing in the later stage, increase the crosslinking density between molecules, and enhance the adhesion to the substrate.

[0027] 2) This invention modifies the silane coupling agent with castor oil, which on the one hand improves the environmental friendliness of the coupling agent, and on the other hand, the long flexible molecular chain of castor oil enhances the flexibility of the adhesive. Castor oil has relatively high functionality and contains ester bonds, which enhances the mechanical properties of the colloid and increases the degree of cross-linking between molecules, thereby enhancing the adhesion of the colloid to the substrate.

[0028] 3) This invention uses 3-methacryloxypropyltrimethoxysilane as a diluent monomer. It has both carbon-carbon double bond structure and siloxane group. It can not only participate in the UV curing process, but also accelerate the speed of moisture curing and improve the adhesion and excellent mechanical properties of the colloid.

[0029] 4) The preparation method of the bio-based dual-curing adhesive provided by the present invention is simple, low-cost, and convenient for production conversion. Its molecular structure not only endows it with excellent hydrophobic properties and environmental friendliness, but also has the characteristics of UV rapid curing and can be post-cured by moisture to enhance adhesion. At the same time, UV / moisture dual curing also broadens the application field, especially in the application of bonding opaque materials or dark reaction areas. Detailed Implementation

[0030] The present invention will be further described below with reference to the embodiments.

[0031] Unless otherwise specified, all raw materials used in the examples were commercially available.

[0032] INOVOL C210, Shandong Yinuowei New Materials Co., Ltd. (Propylene glycol as initiator, functionality 2, number average molecular weight 1000 g / mol).

[0033] INOVOL C220, Shandong Yinuowei New Material Co., Ltd. (Propylene glycol as initiator, functionality 2, number average molecular weight 2000 g / mol).

[0034] INOVOL C230, Shandong Yinuowei New Material Co., Ltd. (Propylene glycol as initiator, functionality 2, number average molecular weight 3000 g / mol).

[0035] BP-2790D, Sinochem Dongda (Zibo) Co., Ltd. (castor oil as initiator, functionality 2.7, number average molecular weight 1000 g / mol);

[0036] BP-2740D, Sinochem Dongda (Zibo) Co., Ltd. (castor oil as initiator, functionality 2.7, number average molecular weight 2000 g / mol);

[0037] BP-2730D, Sinochem Dongda (Zibo) Co., Ltd. (castor oil as initiator, functionality 2.7, number average molecular weight 3000 g / mol).

[0038] Fumed silica, AEROSIL® R805, Evonik Industries.

[0039] Preparation of modified silane coupling agent A1: Weigh 100g castor oil (number average molecular weight 930g / mol) and 44g 3-isocyanate-propyltrimethoxysilane and add them to a reaction vessel under nitrogen protection. The reaction temperature is 70℃. Once the reaction is complete, modified silane coupling agent A1 (number average molecular weight 1340g / mol) is obtained.

[0040] Preparation of modified silane coupling agent A2: 100g castor oil and 26.6g 3-isocyanate-propyltriethoxysilane were weighed and added to a reaction vessel under nitrogen protection. The reaction temperature was 80℃. After the reaction was complete, modified silane coupling agent A2 (number average molecular weight of 1177g / mol) was obtained.

[0041] Example 1

[0042] The preparation method of the aforementioned bio-based dual-curing adhesive includes the following steps:

[0043] (1) Preparation of UV / moisture dual-curing bio-based modified resin:

[0044] a. Add 46.62g of isophorone diisocyanate and 100g of BP-2790D to a reaction vessel under nitrogen protection. The reaction temperature is 80℃. Once the reaction is complete, the prepolymer (number average molecular weight is 1444g / mol) is obtained.

[0045] b. Take 100g of prepolymer, add 20.57g of phytol, and keep the reaction at 80℃. After the reaction is complete, add 92.8g of modified silane coupling agent A1 and continue to keep the reaction at 80℃ until the viscosity of the material no longer changes, thus obtaining the UV / moisture dual-curing bio-based modified resin.

[0046] (2) Preparation of adhesive: By mass, 60 parts of the UV / moisture dual-curing bio-based modified resin of step (1) and 30 parts of 3-methacryloyloxypropyltrimethoxysilane were added to a mixer in sequence. The temperature was controlled at 60°C and the vacuum condition was -0.09MPa. The mixture was stirred at 800 rpm for 1 hour. 1 part of aminopropyltrimethoxysilane, 3 parts of 1-hydroxycyclohexylphenyl ketone and 5 parts of fumed silica were added to the mixer. The mixture was kept in the dark and the temperature was controlled at 60°C and the vacuum condition was -0.09MPa. The mixture was stirred at 800 rpm for 1 hour. Nitrogen gas was released to obtain the bio-based dual-curing adhesive.

[0047] Example 2

[0048] The preparation method of the aforementioned bio-based dual-curing adhesive includes the following steps:

[0049] (1) Preparation of UV / moisture dual-curing bio-based modified resin:

[0050] a. Add 17.22g of hexamethylene diisocyanate and 100g of BP-2740D to a reaction vessel under nitrogen protection. The reaction temperature is 80℃. Once the reaction is complete, the prepolymer (number average molecular weight is 2336g / mol) is obtained.

[0051] b. Take 100g of prepolymer, add 13.35g of phytol, and keep the reaction at 80℃. After the reaction is complete, add 52.9g of modified silane coupling agent A2 and continue to keep the reaction at 80℃ until the viscosity of the material no longer changes, thus obtaining the UV / moisture dual-curing bio-based modified resin.

[0052] (2) Preparation of adhesive: By mass, 70 parts of UV / moisture dual-curing bio-based modified resin from step (1) and 20 parts of 3-methacryloyloxypropyltrimethoxysilane were added to a mixer in sequence. The temperature was controlled at 60°C and the vacuum condition was -0.09 MPa. The mixture was stirred at 800 rpm for 1 hour. 5 parts of aminopropyltrimethoxysilane, 1 part of 1-hydroxycyclohexyl phenyl ketone and 3 parts of fumed silica were added to the mixer. The mixture was kept in the dark and the temperature was controlled at 60°C and the vacuum condition was -0.09 MPa. The mixture was stirred at 800 rpm for 1 hour. Nitrogen gas was released to obtain the bio-based dual-curing adhesive.

[0053] Example 3

[0054] The preparation method of the aforementioned bio-based dual-curing adhesive includes the following steps:

[0055] (1) Preparation of UV / moisture dual-curing bio-based modified resin:

[0056] a. Add 17.47g of dicyclohexylmethane diisocyanate and 100g of BP-2730D to a reaction vessel under nitrogen protection. The reaction temperature is 80℃. Once the reaction is complete, the prepolymer (number average molecular weight is 3524g / mol) is obtained.

[0057] b. Take 100g of prepolymer, add 9.27g of phytol, and keep it at 80℃ for reaction. After the reaction is complete, add 41.83g of modified silane coupling agent A1 and continue to keep it at 80℃ for reaction until the viscosity of the material no longer changes, thus obtaining UV / moisture dual-curing bio-based modified resin.

[0058] (2) Preparation of adhesive: By mass, 80 parts of UV / moisture dual-curing bio-based modified resin from step (1) and 10 parts of 3-methacryloyloxypropyltrimethoxysilane were added to a mixer in sequence. The temperature was controlled at 60°C and the vacuum condition was -0.09 MPa. The mixture was stirred at 800 rpm for 1 hour. 4 parts of aminopropyltrimethoxysilane, 5 parts of 1-hydroxycyclohexyl phenyl ketone and 2 parts of fumed silica were added to the mixer. The mixture was kept in the dark and the temperature was controlled at 60°C and the vacuum condition was -0.09 MPa. The mixture was stirred at 800 rpm for 1 hour. Nitrogen gas was released to obtain the bio-based dual-curing adhesive.

[0059] Comparative Example 1

[0060] The preparation method of the aforementioned bio-based dual-curing adhesive includes the following steps:

[0061] (1) Preparation of UV / moisture dual-curing resin:

[0062] a. Add 46.62g of isophorone diisocyanate and 100g of INOVOL C210 to a reaction vessel under nitrogen protection. The reaction temperature is 80℃. Once the reaction is complete, the prepolymer (number average molecular weight is 1444g / mol) is obtained.

[0063] b. Take 100g of prepolymer, add 8.03g of hydroxyethyl acrylate and 0.02g of hydroquinone, and keep it at 80℃ for reaction. After the reaction is complete, add 14.2g of 3-isocyanate-propyltrimethoxysilane and continue to keep it at 80℃ for reaction until the viscosity of the material no longer changes, thus obtaining UV / moisture dual-curing resin.

[0064] (2) Preparation of adhesive: By mass, 60 parts of UV / moisture dual-curing resin from step (1) and 30 parts of hydroxyethyl acrylate were added to a mixer in sequence. The temperature was controlled at 60°C and the vacuum condition was -0.09MPa. The mixture was stirred at 800 rpm for 1 hour. 1 part of aminopropyltrimethoxysilane, 3 parts of 1-hydroxycyclohexyl benzophenone and 5 parts of fumed silica were added to the mixer. The mixture was kept away from light, the temperature was controlled at 60°C and the vacuum condition was -0.09MPa. The mixture was stirred at 800 rpm for 1 hour. Nitrogen gas was released to obtain the dual-curing adhesive.

[0065] Comparative Example 2

[0066] The preparation method of the aforementioned bio-based dual-curing adhesive includes the following steps:

[0067] (1) Preparation of UV / moisture dual-curing resin:

[0068] a. Add 17.22g of hexamethylene diisocyanate and 100g of INOVOL C220 to a reaction vessel under nitrogen protection. The reaction temperature is 80℃. Once the reaction is complete, the prepolymer (number average molecular weight is 2336g / mol) is obtained.

[0069] b. Take 100g of prepolymer, add 13.35g of phytol, and keep it at 80℃ for reaction. After the reaction is complete, add 52.9g of modified silane coupling agent A2 and continue to keep it at 80℃ for reaction until the viscosity of the material no longer changes, thus obtaining UV / moisture dual-curing resin.

[0070] (2) Preparation of adhesive: By mass, 70 parts of UV / moisture dual-curing resin from step (1) and 20 parts of 3-methacryloyloxypropyltrimethoxysilane were added to a mixer in sequence. The temperature was controlled at 60°C and the vacuum condition was -0.09MPa. The mixture was stirred at 800 rpm for 1 hour. 5 parts of aminopropyltrimethoxysilane, 1 part of 1-hydroxycyclohexyl phenyl ketone and 3 parts of fumed silica were added to the mixer. The mixture was kept away from light, and the temperature was controlled at 60°C and the vacuum condition was -0.09MPa. The mixture was stirred at 800 rpm for 1 hour. Nitrogen gas was released to obtain the dual-curing adhesive.

[0071] Comparative Example 3

[0072] The preparation method of the aforementioned bio-based dual-curing adhesive includes the following steps:

[0073] (1) Preparation of UV / moisture dual-curing resin:

[0074] a. Add 17.22g of hexamethylene diisocyanate and 100g of BP-2740D to a reaction vessel under nitrogen protection. The reaction temperature is 80℃. Once the reaction is complete, the prepolymer (number average molecular weight is 2336g / mol) is obtained.

[0075] b. Take 100g of prepolymer, add 5.22g of hydroxyethyl acrylate and 0.02g of hydroquinone, and keep it at 80℃ for reaction. After the reaction is complete, add 10.57g of 3-isocyanate-propyltriethoxysilane and continue to keep it at 80℃ for reaction until the viscosity of the material no longer changes, thus obtaining UV / moisture dual-curing resin.

[0076] (2) Preparation of adhesive: By mass, 70 parts of UV / moisture dual-curing resin from step (1) and 20 parts of hydroxyethyl acrylate were added to a mixer in sequence. The temperature was controlled at 60°C and the vacuum condition was -0.09MPa. The mixture was stirred at 800 rpm for 1 hour. 5 parts of aminopropyltrimethoxysilane, 1 part of 1-hydroxycyclohexyl phenyl ketone and 3 parts of fumed silica were added to the mixer. The mixture was kept in the dark and the temperature was controlled at 60°C and the vacuum condition was -0.09MPa. The mixture was stirred at 800 rpm for 1 hour. Nitrogen gas was released to obtain the dual-curing adhesive.

[0077] Comparative Example 4

[0078] The preparation method of the aforementioned bio-based dual-curing adhesive includes the following steps:

[0079] (1) Preparation of UV / moisture dual-curing resin:

[0080] a. Add 17.47 g of dicyclohexylmethane diisocyanate and 100 g of INOVOL C230 to a reaction vessel under nitrogen protection. The reaction temperature is 80 °C. Once the reaction is complete, the prepolymer (number average molecular weight is 3524 g / mol) is obtained.

[0081] b. Take 100g of prepolymer, add 9.27g of phytol, and keep it at 80℃ for reaction. After the reaction is complete, add 41.83g of modified silane coupling agent A1 and continue to keep it at 80℃ for reaction until the viscosity of the material no longer changes, thus obtaining UV / moisture dual-curing resin.

[0082] (2) Preparation of adhesive: By mass, 80 parts of UV / moisture dual-curing resin from step (1) and 10 parts of 3-methacryloyloxypropyltrimethoxysilane were added to a mixer in sequence. The temperature was controlled at 60°C and the vacuum condition was -0.09MPa. The mixture was stirred at 800 rpm for 1 hour. 4 parts of aminopropyltrimethoxysilane, 5 parts of 1-hydroxycyclohexyl phenyl ketone and 1 part of fumed silica were added to the mixer. The mixture was kept away from light, the temperature was controlled at 60°C and the vacuum condition was -0.09MPa. The mixture was stirred at 800 rpm for 1 hour. Nitrogen gas was released to obtain the dual-curing adhesive.

[0083] The adhesives prepared in Examples 1-3 and Comparative Examples 1-4 were subjected to performance tests, and the test methods are as follows:

[0084] (1) UV curing time: The sample was cured under an LED lamp (300mw / cm²). 2 Irradiation under ultraviolet light (365nm wavelength) until the sample surface is no longer sticky.

[0085] (2) Adhesive hardness test: The sample was tested under an LED light (300mw / cm²). 2After being irradiated with ultraviolet light (365nm wavelength) for 30 seconds, the samples were cured at room temperature (23±2℃) and relative humidity (50±10%) for 7 days. The hardness performance of the samples was then tested in accordance with GB / T 39693.5-2025.

[0086] (3) Tensile strength and elongation at break: The sample was tested under an LED light (300mw / cm²). 2 After being irradiated with ultraviolet light (365nm wavelength) for 30 seconds, the samples were cured at room temperature (23±2℃) and relative humidity (50±10%) for 7 days. The tensile strength and elongation at break of the samples were tested in accordance with GB / T 528-2009.

[0087] (4) Adhesion performance: Apply the product to PVC material for 2-3mm, and test the sample under an LED light (300mw / cm²). 2 The bonding performance after irradiation with 365nm wavelength ultraviolet light for 30s and then curing at room temperature (23±2℃) and relative humidity (50±10%) for 7 days.

[0088] Adhesion performance rating: A cured film that can be completely peeled off the substrate without residue is rated "0"; a cured film that can be peeled off the substrate with trace residue is rated "1". Adhesion performance is assessed based on the amount of residue, with ratings sequentially "2", "3", "4", and "5". A film that cannot be peeled off the substrate even with strong force is rated "5", indicating excellent adhesion performance.

[0089] Table 1. Analysis of Adhesive Performance Indicators

[0090]

[0091] As shown in the table, optimizing the structures of the polyurethane prepolymer and silane coupling agent using phytol and castor oil significantly improved the overall performance of the colloid. Furthermore, the use of 3-methacryloyloxypropyltrimethoxysilane as a diluent monomer, through the synergistic effect of both carbon-carbon double bonds and siloxane groups, enhanced the curing strength of the colloid, significantly improving its adhesiveness and providing excellent mechanical properties. Simultaneously, the use of castor oil-based bio-based polyols not only improved the mechanical properties of the colloid but also enhanced the product's environmental friendliness.

Claims

1. A bio-based dual-cure adhesive, characterized in that, It is prepared from the following parts by weight of raw materials: 60-80 parts of UV / moisture dual-curing bio-based modified resin; 10-30 parts of acrylate reactive diluent monomer; 1-5 parts of adhesion accelerator; 1-5 parts of photoinitiator; 2-5 parts of thixotropic agent; The UV / moisture dual-curing bio-based modified resin is a modified polyurethane resin containing bio-based polyether polyol segments, phytol structural units, and silane coupling agent structural units. The preparation of the UV / moisture dual-curing bio-based modified resin includes the following steps: a. React bio-based polyether polyol and diisocyanate together to obtain a prepolymer; b. Mix the obtained prepolymer with phytol and react them. After the reaction is complete, add a modified silane coupling agent to react, and then obtain a UV / moisture dual-curing bio-based modified resin. The bio-based polyether polyol mentioned in step a is castor oil polyether polyol with a number average molecular weight of 1000~3000 g / mol; The modified silane coupling agent described in step b is obtained by reacting castor oil with isocyanate-based silanes, wherein the isocyanate-based silane is one of 3-isocyanate-propyltrimethoxysilane and 3-isocyanate-propyltriethoxysilane.

2. The bio-based dual cure adhesive of claim 1, wherein, The diisocyanate mentioned in step a is one of isophorone diisocyanate, hexamethylene diisocyanate, and dicyclohexylmethane diisocyanate.

3. The bio-based dual-curing adhesive according to claim 2, characterized in that, The molar ratio of diisocyanate and bio-based polyether polyol in step a is (2~2.1):

1.

4. The bio-based dual-curing adhesive according to claim 1, characterized in that, The molar ratio of the prepolymer to phytol in step b is 1:(1~1.1).

5. The bio-based dual-curing adhesive according to claim 1, characterized in that, The molar ratio of the prepolymer to the modified silane coupling agent in step b is 1:(1~1.1).

6. The bio-based dual-curing adhesive according to claim 1, characterized in that, The molar ratio of castor oil to isocyanate-based silane is 1:(1~2).

7. The bio-based dual-curing adhesive according to claim 1, characterized in that, The acrylate reactive diluent monomer is 3-methacryloyloxypropyltrimethoxysilane.

8. A method for preparing a bio-based dual-curing adhesive according to any one of claims 1 to 7, characterized in that, Includes the following steps: UV / moisture dual-curing bio-based modified resin and acrylate reactive diluent monomers are added to a mixer and stirred under vacuum. Adhesion promoter, photoinitiator and thixotropic agent are added to the mixer and stirred under vacuum in the dark. Nitrogen gas is then released to obtain the bio-based dual-curing adhesive.

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