Photocuring adhesive as well as preparation method and application thereof

Abstract

The invention relates to a photocuring adhesive as well as a preparation method and application thereof. The photocuring adhesive is prepared from the following raw materials: an unsaturated polyether oligomer and a photoinitiator, the unsaturated polyether oligomer is prepared from the following raw materials: alkylene oxide and a carboxyl-containing unsaturated initiator; the molecular structure of the unsaturated polyether oligomer has a carbon-carbon double bond and an alkyl side chain; the molar ratio of the alkylene oxide to the carboxyl-containing unsaturated initiator is (1.5-4): 1. The photocuring adhesive provided by the invention can be directly coated in an underwater environment, in-situ cross-linking curing is realized through ultraviolet light triggering, and the photocuring adhesive has good bonding performance on various base materials; the photo-curing adhesive provided by the invention can keep adhesion stability in various complex solution environments, and can be suitable for ocean engineering maintenance, underwater precision packaging and in-situ repair under complex working conditions.

Description

Technical Field

[0001] This invention relates to the field of adhesive technology, and more particularly to a light-curing adhesive, its preparation method, and its application. Background Technology

[0002] Adhesives, as a key basic material for achieving material bonding, play an indispensable role in aerospace, electronics, biomedicine, and daily life. With the increasing global emphasis on deep-sea resource development, the research and development of underwater adhesives that can achieve in-situ bonding directly in an aquatic environment and provide stable adhesion has become an important development direction in the adhesive field.

[0003] However, achieving high-performance bonding in an aquatic environment presents more severe challenges than in air. First, the presence of water molecules causes adhesives to swell or dissolve, leading to a significant decrease in their cohesive strength. Second, water molecules easily form a hydration layer on the substrate surface, creating a physical barrier that hinders effective molecular interactions between the adhesive's active groups and the substrate surface, resulting in interfacial adhesion failure. To overcome these challenges, existing research has explored various technical approaches, but significant performance bottlenecks and environmental limitations remain. First, the raw materials for most existing adhesives are highly dependent on petroleum-based raw materials, especially acrylic UV-curable adhesives. Their production and use often involve the emission of volatile organic compounds, causing resource consumption and posing certain biotoxicity issues, making it difficult to meet increasingly stringent environmental standards and green manufacturing requirements. Second, existing underwater adhesive products exhibit significant performance degradation in complex aquatic environments (such as seawater and acidic / alkaline solutions). Especially under underwater construction conditions, how to enable adhesives to achieve rapid cross-linking and curing while actively repelling interfacial water molecules through their structural characteristics to establish strong wet bonds remains a common technical challenge for underwater adhesives.

[0004] Therefore, developing a novel underwater adhesive that can effectively overcome the hydration layer barrier during in-situ underwater curing and exhibit excellent adhesion strength in various substrates and complex solution environments is of great significance for promoting technological progress in related fields. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a photocurable adhesive, its preparation method, and its application. This photocurable adhesive can be directly coated in an underwater environment and achieves in-situ cross-linking and curing through ultraviolet light triggering. It exhibits excellent adhesion to various substrates. The photocurable adhesive provided by this invention maintains adhesion stability in various complex solution environments and is suitable for marine engineering maintenance, underwater precision packaging, and in-situ repair under complex working conditions.

[0006] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a photocurable adhesive, wherein the raw materials for preparing the photocurable adhesive include unsaturated polyether oligomers and photoinitiators; The raw materials for preparing the unsaturated polyether oligomers include epoxides and carboxyl-containing unsaturated initiators; The unsaturated polyether oligomer has carbon-carbon double bonds and alkyl side chains in its molecular structure. The molar ratio of the epoxide and the carboxyl-containing unsaturated initiator is (1.5-4):1.

[0007] Among them, (1.5-4):1, for example, can be 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1 or 4:1, etc.

[0008] The unsaturated polyether oligomers provided by this invention have carbon-carbon double bonds and alkyl side chains in their molecular structure. The carbon-carbon double bonds form a cross-linked network after UV cross-linking and curing, which can significantly improve the cohesive force of the UV-curable adhesive. The alkyl side chains can exclude interfacial water molecules, enabling in-situ underwater cross-linking and curing of the UV-curable adhesive, and improving its water resistance and underwater adhesion strength. Furthermore, the UV-curable adhesive prepared by this invention also possesses hydroxyl and carbonyl functional groups in its molecular structure, allowing it to form various non-covalent interactions with different substrate surfaces, achieving strong interfacial adhesion.

[0009] The present invention also specifies that the molar ratio of the epoxide and the carboxyl-containing unsaturated initiator is (1.5-4):1. If too much epoxide is added, the double bond will be over-diluted, resulting in insufficient colloidal crosslinking density. After light exposure, the mixture will only slightly thicken and will not form a three-dimensional network. If too little epoxide is added, the balance between cohesive strength and interfacial hydrophobicity cannot be achieved.

[0010] Preferably, the number-average molecular weight of the unsaturated polyether oligomer is 300-3000 g / mol, for example, it can be 300 g / mol, 500 g / mol, 1000 g / mol, 1500 g / mol, 2000 g / mol, 2500 g / mol or 3000 g / mol.

[0011] Preferably, the alkyl side chain is a C1-C16 alkyl straight chain, and C1-C16 can be, for example, C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15 or C16.

[0012] Preferably, the epoxide includes any one or a combination of at least two of the following: propylene oxide, 1,2-epoxidebutane, 1,2-epoxidepentane, 1,2-epoxidehexane, 1,2-epoxideheptane, 1,2-epoxideoctane, 1,2-epoxidenonane, 1,2-epoxidedecane, 1,2-epoxideundecane, 1,2-epoxidedodecane, 1,2-epoxidetridecane, 1,2-epoxidetetradecane, 1,2-epoxidepentadecane, or 1,2-epoxidehexadecane, and more preferably 1,2-epoxidepentane.

[0013] Based on different epoxy alkane, the unsaturated polyether oligomers prepared by this invention have different molecular weights, but all contain carbon-carbon double bonds and alkyl side chains in their molecular structures. This invention preferably uses 1,2-epoxypentane, which ensures that the alkyl chains can effectively exert their hydrophobic effect without affecting the cohesive strength of the material, thus achieving a good balance between the cohesive strength and interfacial strength of the photocurable adhesive.

[0014] Preferably, the carboxyl-containing unsaturated initiator includes itaconic acid.

[0015] This invention preferably uses itaconic acid as an initiator to catalyze the ring-opening reaction of epoxides to obtain unsaturated polyether oligomers with hydrophobic side chains. As a bio-based raw material, it is a renewable resource. Compared with petrochemical-based monomers such as acrylic acid and methacrylic acid, it can reduce the carbon footprint of photocurable adhesives, which is in line with environmental regulations and the development trend of bio-based materials. Itaconic acid has high polarity. Compared with acrylic acid, acrylic acid tends to form linear, highly hydrophilic polymer chains with a high density of freely accessible carboxyl groups, which easily interact with water molecules, leading to swelling and loss of cohesion. In contrast, itaconic acid has a bifunctional carboxyl structure and substituted vinyl groups, which enable it to effectively incorporate into crosslinked or branched networks.

[0016] Preferably, the molar ratio of the epoxide and the carboxyl-containing unsaturated initiator is 2:1.

[0017] This invention optimizes the gelling properties, mechanical properties, and adhesive strength of UV-curable adhesives by controlling the side chain length of the epoxy alkane and its molar ratio with the carboxyl-containing unsaturated initiator, thus adapting to different application needs and performance requirements. Furthermore, by controlling the side chain length of the epoxy alkane and its molar ratio with the carboxyl-containing unsaturated initiator, this invention determines that the UV-curable adhesive achieves optimal molecular chain flexibility and photosensitive double bond density. The preferred epoxy alkane is 1,2-epoxypentane, and the molar ratio of itaconic acid to 1,2-epoxypentane is 1:2. Under this optimal formulation, the UV-curable adhesive ensures that during underwater in-situ curing, it achieves both close molecular contact with the substrate through active interfacial drainage and the formation of a high-strength cohesive network through efficient UV crosslinking, thereby achieving optimal performance and structurally stable in-situ bonding in complex aquatic environments.

[0018] Preferably, the raw materials for preparing the unsaturated polyether oligomers also include a Lewis acid catalyst.

[0019] Preferably, the Lewis acid catalyst comprises a bimetallic cyanide catalyst.

[0020] Preferably, based on the mass percentage of the unsaturated polyether oligomer being 100%, the catalyst accounts for 0.1-0.5% of the total mass of the unsaturated polyether oligomer, for example, it can be 0.1%, 0.2%, 0.3%, 0.4% or 0.5%, etc.

[0021] Preferably, the photoinitiator comprises any one or a combination of at least two of 1-hydroxycyclohexylbenzophenone, 2-hydroxy-2-methyl-1-phenylpropanone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, benzophenone, or 2,2-dimethoxy-2-phenylacetophenone.

[0022] Preferably, the mass ratio of the unsaturated polyether oligomer photoinitiator to the photoinitiator is 1:(0.005-0.05), for example, it can be 1:0.005, 1:0.01, 1:0.02, 1:0.03, 1:0.04 or 1:0.05, etc.

[0023] In a second aspect, the present invention provides a method for preparing the photocurable adhesive as described in the first aspect, the method comprising the following steps: (1) Mix epoxide, carboxyl-containing unsaturated initiator and optionally catalyst, and react to obtain the unsaturated polyether oligomer; (2) The photoinitiator and the unsaturated polyether oligomer obtained in step (1) are mixed to obtain the photocurable adhesive.

[0024] Preferably, the reaction temperature in step (1) is 60-80℃, for example, 60℃, 65℃, 70℃, 75℃ or 80℃, and the reaction time is 8-16 h, for example, 8 h, 10 h, 12 h, 14 h, 15 h or 16 h.

[0025] Thirdly, the present invention provides a method for using the photocurable adhesive as described in the first aspect, the method comprising the following steps: applying the photocurable adhesive as described in the first aspect to a substrate to be bonded, and performing ultraviolet curing to complete the use of the photocurable adhesive.

[0026] Preferably, the substrate to be bonded includes any one of glass, metal or plastic.

[0027] Preferably, the wavelength of the ultraviolet light used for ultraviolet curing is 254-405 nm, for example, it can be 254 nm, 260 nm, 270 nm, 280 nm, 290 nm, 300 nm, 310 nm, 320 nm, 330 nm, 340 nm, 350 nm, 360 nm, 370 nm, 380 nm, 390 nm, 400 nm or 405 nm, etc.

[0028] Preferably, the energy of the ultraviolet light used for ultraviolet curing is 100-1000 mW / cm². 2 For example, it could be 100mW / cm 2 200 mW / cm 2 300 mW / cm 2 400 mW / cm 2 500 mW / cm 2 600 mW / cm 2 700 mW / cm 2 800mW / cm 2 900 mW / cm 2 Or 1000 mW / cm 2 wait.

[0029] Preferably, the UV curing time is 10-20 min, for example, it can be 10 min, 12 min, 14 min, 15 min, 16 min, 18 min or 20 min.

[0030] Compared with the prior art, the present invention has at least the following beneficial effects: (1) The photocurable adhesive provided by the present invention integrates hydrophobic functional units (alkyl side chains) on the molecular side chains, thereby giving the photocurable adhesive the ability to actively repel water molecules at the curing interface, thus effectively breaking the hydration layer barrier on the substrate surface and solving the technical problem that has long plagued the field of underwater bonding.

[0031] (2) The photocurable adhesive provided by the present invention not only ensures that the polymer network has high cohesive strength, but also realizes the efficient construction of interfacial molecular forces, so that the photocurable adhesive system exhibits excellent wet bonding stability and applicability to multipolar substrates during underwater in-situ curing, providing a new idea for the design of bio-based functional materials in complex solution environments.

[0032] (3) The photocurable adhesive provided by the present invention further optimizes the appearance, mechanical properties and bonding strength by adjusting the side chain length of the epoxy alkane and the molar ratio with the carboxyl-containing unsaturated initiator. It can exhibit excellent bonding strength in underwater and humid environments to meet different application needs and performance requirements.

[0033] (4) The photocurable adhesive provided by the present invention has an interface drainage design strategy based on hydrophobic shielding effect, which breaks through the limitations of traditional underwater adhesives that rely only on polar functional groups or simple hydrophobic modification, and solves the problem of VOC emissions and environmental toxicity caused by traditional petroleum-based photocurable systems from the source. Attached Figure Description

[0034] Figure 1 These are the infrared spectra of the unsaturated polyether oligomer and the photocurable adhesive obtained in Example 1 of this invention. Figure 2 This is the 1H NMR spectrum of the unsaturated polyether oligomer obtained in Example 1 of this invention. Detailed Implementation

[0035] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0036] The specific information of the materials used in the following specific embodiments of the present invention is as follows: The bimetallic cyanide catalyst used in the embodiments and comparative examples of this invention was prepared as follows: Solution A was prepared by dissolving Zn(CH3COO)2·2H2O (0.66 g, 3 mmol) and CH3COOH (5 mL) in deionized water (15 mL). Solution B was prepared by dissolving K3[Co(CN)6] (0.5 g, 1.5 mmol) in deionized water (10 mL). Solution A was heated to 80°C in an oil bath with stirring, and then solution B was slowly added dropwise. The flask was immediately removed from the oil bath after the addition was completed. The precipitate was separated from the suspension by centrifugation, washed three times with deionized water, dried under vacuum at 80°C for 12 h, and finally ground to obtain the bimetallic cyanide catalyst. Propylene oxide: CAS No. 75-56-9, refluxed in calcium hydride for 8 hours and then redistilled for use; 1,2-Epoxybutane: CAS No. 106-88-7, refluxed in calcium hydride for 8 h and then redistilled for use; 1,2-Epoxypentane: CAS No. 1003-14-1, refluxed in calcium hydride for 8 h and then redistilled for use; 1,2-Epoxyoctane: CAS No. 2984-50-1, refluxed in calcium hydride for 8 h and then redistilled for use; 1,2-Epoxydecane: CAS No. 2404-44-6, refluxed in calcium hydride for 8 h and then redistilled for use; Itaconic acid: CAS No. 97-65-4, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; 2,2-Dimethoxy-2-phenylacetophenone: CAS No. 24650-42-8, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0037] Example 1 This embodiment provides a photocurable adhesive and its preparation method. The photocurable adhesive is prepared by the following method: (1) Add 1,2-epoxypentane (8.6 g, 0.1 mol), itaconic acid (6.5 g, 0.05 mol), and a bimetallic cyanide catalyst (50 mg) to a 100 mL glass bottle. Stir the reaction mixture and heat it to 75 °C for 10 h. After cooling to room temperature (25 °C), remove the bimetallic cyanide catalyst by filtration to obtain the unsaturated polyether oligomer.

[0038] (2) The unsaturated polyether oligomer and 2,2-dimethoxy-2-phenylacetophenone were mixed at a mass ratio of 1:0.01 to obtain the photocurable adhesive.

[0039] The unsaturated polyether oligomer and photocurable adhesive prepared in Example 1 were characterized using an infrared spectrometer (Thermo Science iS50). The infrared spectra are shown below. Figure 1 As shown, from Figure 1 As can be seen from the above, the carbon-carbon double bonds (1641 cm⁻¹) in the prepared photocurable adhesive are... -1 The disappearance of the characteristic peaks proves the successful synthesis of unsaturated polyether oligomers and photocurable adhesives.

[0040] The unsaturated polyether oligomers prepared in Example 1 were characterized using a nuclear magnetic resonance spectrometer (BRUKER AVANCE III HD 600). The proton nuclear magnetic resonance spectrum is shown below. Figure 2 As shown, from Figure 2 As can be seen from the data, the position with a chemical shift of 5-6 ppm represents the vinyl hydrogen (-C=CH2-, a) signal peak in the itaconic acid unit, and the position with a chemical shift of 0.8-0.9 ppm represents the methyl hydrogen (-CH3, b) signal peak in the 1,2-epoxypentane repeating unit, which proves the successful synthesis of unsaturated polyether oligomers.

[0041] Example 2 This embodiment provides a photocurable adhesive and its preparation method. The photocurable adhesive is prepared by the following method: (1) Add 1,2-epoxypentane (8.6 g, 0.1 mol), itaconic acid (4.34 g, 0.033 mol), and a bimetallic cyanide catalyst (40 mg) to a 100 mL glass bottle. Stir the reaction mixture and heat it to 75 °C for 10 h. After cooling to room temperature (25 °C), remove the bimetallic cyanide catalyst by filtration to obtain the unsaturated polyether oligomer.

[0042] (2) The unsaturated polyether oligomer and 2,2-dimethoxy-2-phenylacetophenone were mixed at a mass ratio of 1:0.01 to obtain the photocurable adhesive.

[0043] Example 3 This embodiment provides a photocurable adhesive and its preparation method. The photocurable adhesive is prepared by the following method: (1) Add 1,2-epoxypentane (8.6 g, 0.1 mol), itaconic acid (3.25 g, 0.025 mol), and bimetallic cyanide catalyst (36 mg) to a 100 mL glass bottle. Stir the reaction mixture and heat it to 75 °C for 10 h. After cooling to room temperature (25 °C), remove the bimetallic cyanide catalyst by filtration to obtain the unsaturated polyether oligomer.

[0044] (2) The unsaturated polyether oligomer and 2,2-dimethoxy-2-phenylacetophenone were mixed at a mass ratio of 1:0.01 to obtain the photocurable adhesive.

[0045] Example 4 This embodiment provides a photocurable adhesive and its preparation method. The photocurable adhesive is prepared by the following method: (1) Add 1,2-epoxypentane (8.6 g, 0.1 mol), itaconic acid (8.72 g, 0.067 mol), and a bimetallic cyanide catalyst (52 mg) to a 100 mL glass bottle. Stir the reaction mixture and heat it to 75 °C for 10 h. After cooling to room temperature (25 °C), remove the bimetallic cyanide catalyst by filtration to obtain the unsaturated polyether oligomer.

[0046] (2) The unsaturated polyether oligomer and 2,2-dimethoxy-2-phenylacetophenone were mixed at a mass ratio of 1:0.01 to obtain the photocurable adhesive.

[0047] Example 5 This embodiment provides a photocurable adhesive and its preparation method, which differs from Embodiment 1 in that: 1,2-epoxypentane (8.6 g, 0.1 mol) is replaced with propylene oxide (5.8 g, 0.1 mol).

[0048] Example 6 This embodiment provides a photocurable adhesive and its preparation method, which differs from Embodiment 1 in that: 1,2-epoxypentane (8.6 g, 0.1 mol) is replaced with 1,2-epoxybutane (7.2 g, 0.1 mol) in equal molar amounts.

[0049] Example 7 This embodiment provides a photocurable adhesive and its preparation method, which differs from Embodiment 1 in that: 1,2-epoxypentane (8.6 g, 0.1 mol) is replaced with 1,2-epoxyoctane (12.8 g, 0.1 mol).

[0050] Example 8 This embodiment provides a photocurable adhesive and its preparation method, which differs from Embodiment 1 in that: 1,2-epoxypentane (8.6 g, 0.1 mol) is replaced with 1,2-epoxydecane (15.6 g, 0.1 mol).

[0051] Comparative Example 1 This comparative example provides a photocurable adhesive and its preparation method, wherein the photocurable adhesive is prepared by the following method: (1) Add 1,2-epoxypentane (8.6 g, 0.1 mol), itaconic acid (2.6 g, 0.019 mol), and bimetallic cyanide catalyst (34 mg) to a 100 mL glass bottle. Stir the reaction mixture and heat it to 75 °C for 10 h. After cooling to room temperature (25 °C), remove the bimetallic cyanide catalyst by filtration to obtain the unsaturated polyether oligomer.

[0052] (2) The unsaturated polyether oligomer and 2,2-dimethoxy-2-phenylacetophenone were mixed at a mass ratio of 1:0.01 to obtain the photocurable adhesive.

[0053] Comparative Example 2 This comparative example provides a photocurable adhesive and its preparation method, wherein the photocurable adhesive is prepared by the following method: (1) 1,2-epoxypentane (8.6 g, 0.1 mol), itaconic acid (2.2 g, 0.016 mol), and bimetallic cyanide catalyst (33 mg) were added to a 100 mL glass bottle. The reaction mixture was stirred and heated to 75 °C for 10 h. After cooling to room temperature (25 °C), the bimetallic cyanide catalyst was removed by filtration to obtain the unsaturated polyether oligomer.

[0054] (2) The unsaturated polyether oligomer and 2,2-dimethoxy-2-phenylacetophenone were mixed at a mass ratio of 1:0.01 to obtain the photocurable adhesive.

[0055] Comparative Example 3 This comparative example provides a photocurable adhesive and its preparation method, wherein the photocurable adhesive is prepared by the following method: (1) Add 1,2-epoxypentane (8.6 g, 0.1 mol), itaconic acid (13 g, 0.1 mol), and a bimetallic cyanide catalyst (65 mg) to a 100 mL glass bottle. Stir the reaction mixture and heat it to 75 °C for 10 h. After cooling to room temperature (25 °C), remove the bimetallic cyanide catalyst by filtration to obtain the unsaturated polyether oligomer.

[0056] (2) The unsaturated polyether oligomer and 2,2-dimethoxy-2-phenylacetophenone were mixed at a mass ratio of 1:0.01 to obtain the photocurable adhesive.

[0057] Test methods The following performance tests were performed on the photocurable adhesives described in the examples and comparative examples: (1) Air adhesion strength: Take a sample with a material size of 100 mm × 25 mm. The substrate of the sample includes glass, ceramic, steel, aluminum, titanium, copper, epoxy resin, and PMMA. Apply 25 mg of the light-curing adhesive provided in the example or comparative example between two sample strips of the same material. The bonding area is 25 mm × 2 mm. Then, at 365 nm and 500 mW / cm², the adhesive is applied to the sample. 2 The samples were cured by irradiation under ultraviolet light for 15 minutes. The bond strength was tested using a universal tensile testing machine at a tensile rate of 5 mm / min. A complete test was performed when the two samples were completely separated. A total of 3 tests were conducted, and the average value was taken.

[0058] (2) Underwater adhesive strength test: First, place the UV-curable adhesive to be tested in a syringe, and perform the coating and bonding operations on the substrate in a water-filled experimental environment. Take a glass sample with a material size of 100 mm × 25 mm, apply 25 mg of the UV-curable adhesive provided in the example or comparative example between two sample strips, with a bonding area of ​​25 mm × 2 mm, and then cure it underwater with 365 nm ultraviolet light for 15 min. The adhesive strength is tested using a universal tensile testing machine at a tensile rate of 5 mm / min. A complete test is performed when the two samples are completely separated. A total of 3 tests are conducted, and the average value is taken.

[0059] (3) Bond strength test under different environments: 50 mg of the UV-curable adhesive provided in the examples or comparative examples was applied between two glass substrates (coating area 25 mm × 4 mm) in artificial seawater (1M NaCl), alkaline solution (pH=12), acidic solution (pH=2), and dimethyl silicone oil. The adhesive was then cured underwater by irradiation with 365 nm UV light for 15 min. The bond strength was tested using a universal tensile testing machine at a tensile rate of 5 mm / min. A complete test was performed when the two samples were completely separated. Three tests were conducted, and the average value was taken.

[0060] (4) Bond strength test under different UV curing times: Take a glass sample with a material size of 100 mm × 25 mm, apply 25 mg of the UV-curable adhesive provided in the example or comparative example between two glass samples, with a bonding area of ​​25 mm × 2 mm, and then irradiate it under 365 nm UV light for 5 min, 10 min, 15 min, and 20 min to cure it. The bond strength is tested using a universal tensile testing machine at a tensile rate of 5 mm / min. The test is completed when the two samples are completely separated. A total of 3 tests are conducted, and the average value is taken.

[0061] The test results are shown in Table 1-4: Table 1 Table 2 Table 3 Table 4 The test results show that: (1) As can be seen from Examples 1 to 8, the photocurable adhesive provided by the present invention can be directly coated in an underwater environment, and in-situ cross-linking and curing are achieved by ultraviolet light triggering. It has good adhesion performance to a variety of substrates. The photocurable adhesive provided by the present invention can maintain adhesion stability in a variety of complex solution environments, and can be used for marine engineering maintenance, underwater precision packaging and in-situ repair under complex working conditions. The adhesive strength of the photocurable adhesive provided by the present invention in air can reach 1.22-12.70 MPa, and the adhesive strength in water can reach 0.87-10.87 MPa.

[0062] (2) As can be seen from Examples 1 to 4 and Comparative Examples 1 to 3, by further limiting the molar ratio of epoxides and carboxyl-containing unsaturated initiators, the present invention cannot effectively form gels if too much or too little of any substance is added.

[0063] (3) As can be seen from Examples 1 and 5-8, the present invention further prefers 1,2-epoxypentane as an epoxyalkane, which ensures that the alkyl chain can play a good role in hydrophobicity without affecting the cohesive strength of the material, and can better balance the cohesive strength and interfacial strength of the adhesive.

[0064] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A light-curing adhesive, characterized in that, The raw materials for preparing the photocurable adhesive include unsaturated polyether oligomers and photoinitiators; The raw materials for preparing the unsaturated polyether oligomers include epoxides and carboxyl-containing unsaturated initiators; The unsaturated polyether oligomer has carbon-carbon double bonds and alkyl side chains in its molecular structure. The molar ratio of the epoxide and the carboxyl-containing unsaturated initiator is (1.5-4):

1.

2. The photocurable adhesive according to claim 1, characterized in that, The number-average molecular weight of the unsaturated polyether oligomer is 300-3000 g / mol.

3. The photocurable adhesive according to claim 1 or 2, characterized in that, The alkyl side chain is a C1-C16 alkyl straight chain; Preferably, the epoxide includes any one or a combination of at least two of the following: propylene oxide, 1,2-epoxidebutane, 1,2-epoxidepentane, 1,2-epoxidehexane, 1,2-epoxideheptane, 1,2-epoxideoctane, 1,2-epoxidenonane, 1,2-epoxidedecane, 1,2-epoxideundecane, 1,2-epoxidedodecane, 1,2-epoxidetridecane, 1,2-epoxidetetradecane, 1,2-epoxidepentadecane, or 1,2-epoxidehexadecane, and more preferably 1,2-epoxidepentane; Preferably, the carboxyl-containing unsaturated initiator includes itaconic acid.

4. The photocurable adhesive according to any one of claims 1-3, characterized in that, The molar ratio of the epoxide and the carboxyl-containing unsaturated initiator is 2:

1.

5. The photocurable adhesive according to any one of claims 1-4, characterized in that, The raw materials for preparing the unsaturated polyether oligomers also include Lewis acid catalysts; Preferably, the Lewis acid catalyst comprises a bimetallic cyanide catalyst; Preferably, the catalyst accounts for 0.1-0.5% of the total mass of the unsaturated polyether oligomer, based on a mass percentage of 100% for the unsaturated polyether oligomer.

6. The photocurable adhesive according to any one of claims 1-5, characterized in that, The photoinitiator includes any one or a combination of at least two of 1-hydroxycyclohexylbenzophenone, 2-hydroxy-2-methyl-1-phenylpropanone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, benzophenone or 2,2-dimethoxy-2-phenylacetophenone. Preferably, the mass ratio of the unsaturated polyether oligomer photoinitiator to the photoinitiator is 1:(0.005-0.05).

7. A method for preparing a photocurable adhesive as described in any one of claims 1-6, characterized in that, The preparation method includes the following steps: (1) Mix epoxide, carboxyl-containing unsaturated initiator and optionally catalyst, and react to obtain the unsaturated polyether oligomer; (2) The photoinitiator and the unsaturated polyether oligomer obtained in step (1) are mixed to obtain the photocurable adhesive.

8. The method for preparing the photocurable adhesive according to claim 7, characterized in that, The reaction temperature in step (1) is 60-80℃, and the reaction time is 8-16 h.

9. A method of using a light-curing adhesive as described in any one of claims 1-6, characterized in that, The method of use includes the following steps: applying the photocurable adhesive according to any one of claims 1-6 onto the substrate to be bonded, and then curing it with ultraviolet light to complete the use of the photocurable adhesive.

10. The method of use according to claim 9, characterized in that, The substrate to be bonded includes any one of glass, metal or plastic; Preferably, the wavelength of the ultraviolet light used for ultraviolet curing is 254-405 nm; Preferably, the energy of the ultraviolet light used for ultraviolet curing is 100-1000 mW / cm². 2 ; Preferably, the UV curing time is 10-20 min.

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