A low water absorption, voltage-resistant polyurethane acrylate adhesive and its preparation method

Abstract

This application relates to the field of polyurethane acrylate adhesives, and more specifically, to a low-water-absorption, voltage-resistant polyurethane acrylate adhesive and its preparation method. It is prepared from the following raw materials in weight percentages: 45-55% polyurethane acrylate, 8-12% polyfunctional glycidyl ether epoxy resin, 1-2% initiator, 4-6% water-repellent agent, and the remainder being an active diluent. The water-repellent agent is composed of fatty alcohol polyoxyethylene (3) ether, polydimethylsiloxane, and sodium methylsiloxane. The low-water-absorption, voltage-resistant polyurethane acrylate adhesive prepared by the above formulation exhibits good voltage resistance and low water absorption, effectively solving problems such as unstable bonding, easy aging, and decreased mechanical properties of components such as connectors, nickel sheets, and negative temperature coefficient thermistors in high-humidity environments. The application of this adhesive will significantly improve the reliability and durability of these components in humid environments, extending their service life.

Description

Technical Field

[0001] This application relates to the field of polyurethane acrylate adhesives, and more specifically, to a low water absorption, voltage-resistant polyurethane acrylate adhesive and its preparation method. Background Technology

[0002] Polyurethane acrylate adhesive is mainly used in components such as connectors, nickel contacts, and negative temperature coefficient (NTC) thermistors to ensure solid bonding of the various parts of the connector, nickel contacts, and NTC thermistors. However, these components are sometimes used in high-humidity environments. For example, connectors are used in weather stations and environmental monitoring equipment, which are typically exposed to the natural environment and susceptible to the effects of rain, fog, and other humid factors. Similarly, components like batteries and fuel cells undergo chemical reactions during operation, leading to increased humidity in the surrounding environment and placing the nickel contacts in a high-humidity environment. NTC thermistors are used in outdoor temperature measurement equipment, such as agricultural meteorological monitoring stations and environmental monitoring equipment, which are also typically exposed to the natural environment and susceptible to the effects of humidity.

[0003] High humidity environments can cause polyurethane acrylate adhesives to increase in size, potentially affecting their physical and chemical properties. Specifically, it can reduce the voltage withstand capability of urethane acrylate adhesives, meaning that under humid conditions, the adhesive's insulation properties may be compromised, increasing the risk of short circuits or electrical faults. Furthermore, adhesion performance will decrease, leading to unstable connections between components, and even potential detachment or breakage. Simultaneously, aging resistance and mechanical properties are also affected by humidity. Prolonged exposure to high humidity may accelerate the aging of polyurethane acrylate adhesives, causing cracking, hardening, or softening, thereby reducing their service life and reliability. Mechanical properties, such as tensile strength and shear strength, may also decrease, affecting the overall stability and durability of components. Summary of the Invention

[0004] In order to reduce the water absorption of polyurethane acrylate adhesive and enhance its voltage resistance, adhesion and aging resistance, this application provides a low water absorption voltage-resistant polyurethane acrylate adhesive and its preparation method.

[0005] In a first aspect, this application provides a low-water-absorption, voltage-resistant polyurethane acrylate adhesive, employing the following technical solution:

[0006] A low-absorption, voltage-resistant polyurethane acrylate adhesive is prepared from the following raw materials by weight percentage:

[0007] 45-55% polyurethane acrylate

[0008] Multifunctional glycidyl ether epoxy resin 8-12%

[0009] Photoinitiator 1-2%

[0010] Water-repellent agent 4-6%

[0011] The remainder is reactive diluent;

[0012] The water-repellent agent is composed of fatty alcohol polyoxyethylene (3) ether, polydimethylsiloxane and sodium methylsiloxane.

[0013] By adopting the above technical solution, polyurethane acrylate is used as the main matrix resin, ensuring good adhesion and physical and mechanical properties. Simultaneously, multifunctional glycidyl ether epoxy resin is added to enhance the crosslinking density and chemical resistance of the colloid, thereby improving its voltage resistance. The water-repellent agent in this application, composed of fatty alcohol polyoxyethylene (3) ether, polydimethylsiloxane, and sodium methylsiloxane, can significantly reduce the water absorption rate of the colloid, effectively preventing moisture from penetrating into the colloid and thus avoiding problems such as increased size and reduced voltage resistance.

[0014] The ethoxy chain segment in the molecular structure of fatty alcohol polyoxyethylene (3) ether can form an effective hydrophobic barrier, preventing the penetration of water molecules. Polydimethylsiloxane and fatty alcohol polyoxyethylene (3) ether work synergistically to form a denser hydrophobic layer, effectively reducing the water absorption rate of the colloid. Sodium methylsiloxane, as an auxiliary component, helps to regulate the overall performance of the hydrophobic agent, making it more stable. That is, the addition of the hydrophobic agent effectively prevents water from penetrating into the interior of the colloid, reducing the risk of size increase and voltage reduction due to water absorption, thereby improving the safety and stability of the circuit. Even in humid environments, the colloid can still maintain good adhesive strength, ensuring a firm connection between components and avoiding detachment or breakage. The hydrophobic agent can also effectively prevent the colloid from aging faster due to water absorption, maintaining its good tensile strength, shear strength and other mechanical properties, extending the service life and reliability of components.

[0015] Preferably, the weight ratio of the fatty alcohol polyoxyethylene (3) ether, the polydimethylsiloxane and the sodium methylsiloxane is 10:(3-5):1.

[0016] By adopting the above technical solution and optimizing the dosage of fatty alcohol polyoxyethylene (3) ether, polydimethylsiloxane, and sodium methylsiloxane, the hydrophobic properties of the polyurethane acrylate adhesive are further enhanced, effectively blocking the penetration of water molecules. This also significantly improves its voltage resistance in high-humidity environments, ensuring the safety and stability of electrical insulation. Simultaneously, this combination maintains stable adhesion of the adhesive under humid conditions, preventing the detachment or breakage of connected components, thereby enhancing the overall durability and reliability of the components. Furthermore, this formulation also helps improve the anti-aging properties and mechanical properties of the adhesive, extending the service life of the components.

[0017] Preferably, the polyurethane acrylate is obtained by the following method:

[0018] 1) Add isooctyl acrylate, methyl methacrylate, acrylamide, organosilicon monomer and initiator to the reactor, heat to 75-85℃, reflux for 2-3 hours to obtain acrylate polymer;

[0019] 2) Add polypropylene glycol and polyether polyol to the reactor, then heat and stir in an oil bath at 110-120℃, and treat under vacuum. When the reactor reaches 110-120℃, add isocyanate and catalyst under nitrogen protection, and react for 1-1.5 hours to end the reaction. Then, vacuum distill to remove bubbles from the product for 0.5 hours. When there are no bubbles in the product, introduce nitrogen, adjust the reaction temperature to 90-95℃, add hydroxyethyl acrylate, and react for 1-1.5 hours to obtain polyurethane polymer.

[0020] 3) Add the acrylate polymer and polyurethane polymer to the reactor, heat to 80-85℃ and react for 2-3 hours to obtain polyurethane acrylate.

[0021] By adopting the above technical solution, acrylate polymers and polyurethane polymers can be effectively combined to form a polyurethane acrylate that combines the advantages of both. The acrylate polymer imparts good weather resistance, water resistance, and gloss to the product, while the polyurethane polymer provides excellent flexibility, abrasion resistance, and adhesion.

[0022] By precisely controlling the polymerization reaction of isooctyl acrylate, methyl methacrylate, acrylamide, organosilicon monomers, and initiators, a structurally stable and high-performance acrylate polymer was obtained. This step not only ensured the regular arrangement of polymer chain segments but also endowed the polymer with good water resistance and weather resistance, effectively reducing the water absorption of polyurethane acrylate. The reaction of polypropylene glycol, polyether polyol, and isocyanate formed a polyurethane polymer, further enhancing the overall hydrophobicity. This enhanced hydrophobicity helps reduce water molecule absorption, improving the product's water resistance. The acrylate polymer and polyurethane polymer are chemically bonded together, further improving the overall structural compactness and hydrophobicity. This compact structure helps reduce water molecule penetration channels, thereby further reducing water absorption.

[0023] Meanwhile, since both acrylate polymers and polyurethane polymers possess good insulating properties, the polyurethane acrylate obtained through copolymerization also exhibits excellent insulating properties. This improved insulation helps reduce the risk of electrical breakdown in products under high voltage, thereby enhancing their voltage withstand capability.

[0024] Preferably, the weight ratio of isooctyl acrylate, methyl methacrylate, acrylamide, organosilicon monomer and initiator is 10:(0.5-1):(2-3):(1-2):(0.2-0.5).

[0025] By adopting the above technical solution and optimizing the ratio of various raw materials, the structure and properties of acrylate polymers can be precisely controlled. The resulting polyurethane acrylate adhesive has lower water absorption, higher voltage resistance, and more stable bonding performance. It can maintain excellent physical and chemical properties in high humidity environments and meet the bonding requirements of various components.

[0026] Preferably, the weight ratio of the polypropylene glycol, the polyether polyol, the isocyanate, the catalyst, and the hydroxyethyl acrylate is 10:(4-8):(6-9):(0.1-0.3):(0.3-0.5).

[0027] By adopting the above technical solution, the synthesis process of polyurethane polymer can be precisely controlled, which not only ensures that the polyurethane polymer has excellent chemical resistance and physical properties, but also provides a stable backbone and functional groups for the subsequent synthesis of polyurethane acrylate.

[0028] Preferably, the weight ratio of the acrylate polymer to the polyurethane polymer is 1:(2-3).

[0029] By adopting the above technical solution, the complementary advantages of both materials in terms of structure and performance can be fully utilized. Acrylic polymers provide good flexibility and weather resistance, while polyurethane polymers enhance chemical resistance and physical strength. This formulation results in a polyurethane-acrylate adhesive with not only lower water absorption and higher voltage resistance, but also more stable bonding performance, maintaining excellent performance in high-humidity environments. This optimized formulation makes the polyurethane-acrylate adhesive more suitable for bonding components under various harsh conditions, improving the overall reliability and durability of the product.

[0030] Preferably, the organosilicon monomer is vinyltriethoxysilane or / and methacryloyloxypropyltrimethoxysilane.

[0031] By precisely controlling the ratio and reaction conditions of these two organosilicon monomers, polyurethane acrylate adhesives with lower water absorption, higher voltage resistance, and more stable bonding performance can be prepared to meet the bonding requirements of various high-requirement components.

[0032] Preferably, the active diluent is at least one selected from neopentyl glycol glycidyl ether, diethylene glycol glycidyl ether, benzyl glycidyl ether, tert-butylphenol glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, n-octanol glycidyl ether, C12-14 alcohol glycidyl ether, phenyl glycidyl ether, o-cresol glycidyl ether, ethylene glycol glycidyl ether, butanediol glycidyl ether, hexanediol glycidyl ether, glycerol glycidyl ether, and trimethylolpropane glycidyl ether.

[0033] By adopting the above technical solutions, not only can the viscosity of the colloid be effectively adjusted, facilitating processing and application, but it can also form good compatibility with main resins such as polyurethane acrylate and multifunctional glycidyl ether epoxy resin. Simultaneously, these active diluents can participate in the polymerization reaction, improving the crosslinking density and stability of the colloid. Therefore, polyurethane acrylate adhesives prepared using these reactive diluents exhibit lower water absorption, higher voltage resistance, and more stable bonding performance, maintaining excellent physical and chemical properties even in high-humidity environments, meeting the bonding requirements of various components.

[0034] Secondly, this application provides a method for preparing a low-water-absorption, voltage-resistant polyurethane acrylate adhesive, using the following technical solution:

[0035] A method for preparing a low-water-absorption, voltage-resistant polyurethane acrylate adhesive includes the following steps:

[0036] Polyurethane acrylate, multifunctional glycidyl ether epoxy resin, photoinitiator, water-repellent agent and reactive diluent are stirred evenly to obtain a low water absorption and voltage resistant polyurethane acrylate adhesive.

[0037] By adopting the above technical solution, polyurethane acrylate, multifunctional glycidyl ether epoxy resin, photoinitiator, hydrophobic agent and reactive diluent can be fully mixed to form a uniform and stable low water absorption voltage resistant polyurethane acrylate adhesive.

[0038] In summary, this application has the following beneficial effects:

[0039] 1. Low water absorption: By introducing a water-repellent agent, the penetration of water molecules is effectively blocked, reducing the water absorption rate and thus maintaining the dimensional stability of the colloid in a high-humidity environment.

[0040] 2. Improved voltage resistance: The addition of water-repellent agent not only reduces water absorption but also enhances the insulation performance of polyurethane acrylate adhesive, reducing the risk of short circuits or electrical failures under humid conditions.

[0041] 3. Stable Adhesion Performance: By using a combination of polyurethane acrylate, polyurethane acrylate adhesive multifunctional glycidyl ether epoxy resin, photoinitiator, water-repellent agent, and reactive diluent, the polyurethane acrylate adhesive maintains stable adhesion performance even in high-humidity environments. This ensures a strong and reliable connection between components, reducing the likelihood of detachment or breakage. Simultaneously, it improves the polyurethane acrylate adhesive's tolerance to humid environments, reduces aging, and extends its service life. Detailed Implementation

[0042] Example

[0043] The polyurethane acrylate used in Examples 1-3 was purchased from Hunan Jinhai Technology Co., Ltd., and its brand name was JS312.

[0044] The multifunctional glycidyl ether epoxy resins used in Examples 1-3 were purchased from Guangzhou Huali Trading Co., Ltd., and the model was American Hansen multifunctional epoxy resin EPON 1031.

[0045] The polydimethylsiloxane used in Examples 1-3 was purchased from Shenzhen Xinyongsheng New Materials Co., Ltd., model number 26710-23-6.

[0046] The polypropylene glycol was purchased from Haian Petrochemical Plant in Jiangsu Province, and its model number is PPG-425.

[0047] Polyether diol D2000, purchased from Haian Petrochemical Plant in Jiangsu Province, brand name DL-2000D.

[0048] Example 1

[0049] A low-water-absorption, voltage-resistant polyurethane acrylate adhesive is prepared by the following method:

[0050] 450g of polyurethane acrylate, 120g of multifunctional glycidyl ether epoxy resin, 20g of photoinitiator (1-hydroxycyclohexylphenyl ketone), 60g of water repellent and 350g of reactive diluent (neopentyl glycol glycidyl ether) were stirred evenly to obtain a low water absorption and voltage resistant polyurethane acrylate adhesive.

[0051] The water-repellent agent is composed of fatty alcohol polyoxyethylene (3) ether, polydimethylsiloxane and sodium methylsiloxane in a weight ratio of 10:3:1.

[0052] Example 2

[0053] A low-water-absorption, voltage-resistant polyurethane acrylate adhesive is prepared by the following method:

[0054] 500g of polyurethane acrylate, 100g of multifunctional glycidyl ether epoxy resin, photoinitiator 15 (phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide), 50g of water repellent and 335g of reactive diluent (diethylene glycol glycidyl ether) were stirred evenly to obtain a low water absorption and voltage resistant polyurethane acrylate adhesive.

[0055] The water-repellent agent is composed of fatty alcohol polyoxyethylene (3) ether, polydimethylsiloxane, and sodium methylsiloxane in a weight ratio of 10:4:1.

[0056] Example 3

[0057] A low-water-absorption, voltage-resistant polyurethane acrylate adhesive is prepared by the following method:

[0058] 500g of polyurethane acrylate, 80g of multifunctional glycidyl ether epoxy resin, 10g of photoinitiator (phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide), 40g of water repellent and 370g of reactive diluent (tert-butylphenol glycidyl ether) were stirred evenly to obtain a low water absorption and voltage resistant polyurethane acrylate adhesive.

[0059] The water-repellent agent is composed of fatty alcohol polyoxyethylene (3) ether, polydimethylsiloxane and sodium methylsiloxane in a weight ratio of 10:5:1.

[0060] Example 4

[0061] A low water absorption, voltage-resistant polyurethane acrylate adhesive, the difference in this Example 1 is that the weight ratio of fatty alcohol polyoxyethylene (3) ether, polydimethylsiloxane and sodium methylsiloxane is 10:10:1.

[0062] Example 5

[0063] A low-absorption, voltage-resistant polyurethane acrylate adhesive, the difference in this Example 1 is that the polyurethane acrylate is obtained by the following method:

[0064] 1) Add 200g of isooctyl acrylate, 10g of methyl methacrylate, 40g of acrylamide, 20g of organosilicon monomer (vinyltriethoxysilane) and 4g of initiator (benzoyl peroxide) to a reactor, heat to 75°C, and reflux for 2 hours to obtain an acrylate polymer.

[0065] 2) Add 400g of polypropylene glycol and 160g of polyether polyol to the reactor, then heat and stir in an oil bath at 110℃, and treat under vacuum. When the reactor reaches 110℃, under nitrogen protection, add 220g of isocyanate (isophorone diisocyanate) and 4g of catalyst (dibutyltin dilaurate), and react for 1 hour to end the reaction. Then, vacuum distillation is carried out to remove bubbles from the product for 0.5 hours. When there are no bubbles in the product, nitrogen is introduced, the reaction temperature is adjusted to 90℃, 12g of hydroxyethyl acrylate is added, and the reaction is carried out for 1 hour to obtain polyurethane polymer.

[0066] 3) Add 200g of acrylate polymer and 400g of polyurethane polymer to the reactor, heat to 80℃ and react for 2h to obtain polyurethane acrylate.

[0067] The difference between Examples 6-7 and Example 5 lies in the types and amounts of raw materials used to prepare the polyurethane acrylate, as well as the experimental parameters. Specific differences are shown in Table 1.

[0068] Table 1. Types, amounts, and experimental parameters of raw materials used in the preparation of polyurethane acrylates.

[0069]

[0070]

[0071] Example 8

[0072] A low-absorption, voltage-resistant polyurethane acrylate adhesive, the difference in this Example 5 is that the weight ratio of acrylate polymer to polyurethane polymer is 1:1.

[0073] Example 9

[0074] A low-absorption, voltage-resistant polyurethane acrylate adhesive, the difference in this Example 5 is that styrene is used instead of vinyltriethoxysilane.

[0075] Comparative Example

[0076] Comparative Example 1

[0077] A polyurethane acrylate adhesive, the difference between this comparative example and Example 1 is that a fatty acid is used instead of a water-repellent agent.

[0078] Comparative Example 2

[0079] A polyurethane acrylate adhesive, the difference between this comparative example and Example 1 is that fatty acid polyoxyethylene ester is used instead of fatty alcohol polyoxyethylene (3) ether.

[0080] Comparative Example 3

[0081] A polyurethane acrylate adhesive, the difference between this comparative example and Example 1 is that ethyl stearate is used instead of polydimethylsiloxane.

[0082] Comparative Example 4

[0083] A polyurethane acrylate adhesive, the difference between this comparative example and Example 1 is that ethyl acetate is used instead of sodium methylsiloxane.

[0084] Comparative Example 5

[0085] A polyurethane acrylate adhesive, the difference between this comparative example and Example 1 is that methyl glycidyl ether epoxy resin is used instead of multifunctional glycidyl ether epoxy resin.

[0086] The methyl glycidyl ether epoxy resin was purchased from Wuhan Kemic Biomedical Technology Co., Ltd., CAS No. 61788-97-4.

[0087] Test Method / Test Method: Water Absorption Rate: The test was conducted according to the standard ASTM D570-05 Test Method for Water Absorption Rate of Plastics. The low water absorption rate voltage-resistant polyurethane acrylate adhesives of Examples 1-9 and the polyurethane acrylate adhesives of Comparative Examples 1-5 were cured to form samples of 76.2mm×25.4mm×3.2mm. The water absorption rate was tested after immersion in water at 23°C for 24 hours. The water absorption rate was calculated according to the formula in the standard.

[0088] Shear strength: The low water absorption and voltage resistant polyurethane acrylate adhesives of Examples 1-9 and Comparative Examples 1-5 were coated between two substrates, namely a stainless steel specimen and a PET substrate, respectively. The tensile shear strength was tested according to GB / T7124-2008.

[0089] Withstand voltage: Refer to GB / T 16927.1-2011.

[0090] Reliability test: 1) The low water absorption and voltage resistant polyurethane acrylate adhesives of Examples 1-9 and the polyurethane acrylate adhesives of Comparative Examples 1-5 were subjected to a double 85 aging test. The conditions were: after being placed in a constant temperature and humidity chamber at 85°C and 85%RH for 1008 hours, they were taken out, dried, and the shear strength was retested.

[0091] 1. The low-absorption, voltage-resistant polyurethane acrylate adhesives of Examples 1-9 and Comparative Examples 1-5 were subjected to high and low temperature aging tests. The conditions were -40℃ / 12h, 120℃ / 12h, for a total of 500h of high-temperature low-temperature cycling. The shear strength of the adhesives was then retested. The experimental data are shown in Table 2.

[0092] Table 2. Experimental data for the examples and comparative examples.

[0093]

[0094] Comparing Example 1 and Comparative Examples 1-4, the water absorption rate of Comparative Examples 1-4 is greater than that of Example 1, and the shear strength is less than that of Example 1. The voltage resistance of Comparative Examples 1 and 3 is lower than that of Example 1. After the double 85 aging test and the high and low temperature aging test, the shear strength change of Comparative Examples 1-4 is greater than that of Example 1. This shows that by adding fatty alcohol polyoxyethylene (3) ether, polydimethylsiloxane and sodium methylsiloxane as water repellents, this application can effectively reduce the water absorption of polyurethane acrylate adhesive and improve its voltage resistance, shear strength and anti-aging properties.

[0095] Comparing Example 1 and Comparative Example 5, Comparative Example 5 has a higher water absorption rate and a lower shear strength than Example 1. After undergoing the double 85 aging test and the high and low temperature aging test, the shear strength change of Comparative Example 5 is greater than that of Example 1. This indicates that adding polyfunctional glycidyl ether epoxy resin can effectively reduce the water absorption of polyurethane acrylate adhesive and improve its shear strength and anti-aging properties.

[0096] Comparing Example 1 and Example 4, the water absorption rate of Example 4 is greater than that of Example 1, and the shear strength is less than that of Example 1. After the double 85 aging test and the high and low temperature aging test, the shear strength change of Example 4 is greater than that of Example 1. This indicates that optimizing the amount of fatty alcohol polyoxyethylene (3) ether, polydimethylsiloxane and sodium methylsiloxane can effectively reduce the water absorption of polyurethane acrylate adhesive and improve its voltage resistance, shear strength and anti-aging properties.

[0097] Compared with Examples 1, Examples 5-7 all have lower water absorption rates and higher shear strengths than Example 1; Examples 5-7 have higher voltage resistance than Example 1; After undergoing double 85 aging test and high and low temperature aging test, the shear strength change of Examples 5-7 is less than that of Example 1.

[0098] Comparing Example 5 and Example 8, the water absorption rate of Example 5 is lower than that of Example 8, and the shear strength is higher than that of Example 1; the voltage resistance of Example 5 is higher than that of Example 8; after the double 85 aging test and the high and low temperature aging test, the shear strength change of Example 5 is less than that of Example 8.

[0099] Comparing Example 5 and Example 9, the water absorption rate of Example 5 is lower than that of Example 9, and the shear strength is higher than that of Example 1; the voltage resistance of Example 5 is higher than that of Example 9; after the double 85 aging test and the high and low temperature aging test, the shear strength change of Example 5 is less than that of Example 9.

[0100] Data from Examples 1, 5-7, 8, and 9 show that the polyurethane polyacrylate prepared in this application can effectively reduce the water absorption of polyurethane acrylate adhesive and improve its voltage resistance, shear strength, and anti-aging properties.

[0101] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A low-absorption, voltage-resistant polyurethane acrylate adhesive, characterized in that, It is prepared from the following raw materials by weight percentage: Polyurethane acrylate 45-55% Multifunctional glycidyl ether epoxy resin 8-12% Photoinitiator 1-2% Water-repellent agent 4-6% The remainder is reactive diluent; The water-repellent agent is composed of AEO-3, polydimethylsiloxane, and sodium methylsiloxane.

2. The low water absorption and voltage-resistant polyurethane acrylate adhesive according to claim 1, characterized in that: The weight ratio of AEO-3, polydimethylsiloxane, and sodium methylsiloxane is 10:(3-5):

1.

3. The low water absorption and voltage-resistant polyurethane acrylate adhesive according to claim 1, characterized in that, The polyurethane acrylate is obtained by the following method: 1) Add isooctyl acrylate, methyl methacrylate, acrylamide, organosilicon monomer and initiator to the reactor, heat to 75-85℃, reflux for 2-3 hours to obtain acrylate polymer; 2) Polypropylene glycol and polyether polyol are added to the reactor, and then heated and stirred in an oil bath at 110-120℃ under vacuum. When the reactor reaches 110-120℃, isocyanate and catalyst are added under nitrogen protection, and the reaction is stopped after 1-1.5h. Vacuum distillation is then carried out to remove bubbles from the product for 0.5h. When there are no bubbles in the product, nitrogen is introduced, the reaction temperature is adjusted to 90-95℃, hydroxyethyl acrylate is added, and the reaction is carried out for 1-1.5h to obtain polyurethane polymer. 3) Add the acrylate polymer and polyurethane polymer to the reactor, heat to 80-85℃ and react for 2-3 hours to obtain polyurethane acrylate.

4. The low water absorption and voltage-resistant polyurethane acrylate adhesive according to claim 3, characterized in that: The weight ratio of isooctyl acrylate, methyl methacrylate, acrylamide, organosilicon monomer and initiator is 10:(0.5-1):(2-3):(1-2):(0.2-0.5).

5. The low water absorption and voltage-resistant polyurethane acrylate adhesive according to claim 3, characterized in that: The weight ratio of the polypropylene glycol, the polyether polyol, the isocyanate, the catalyst, and the hydroxyethyl acrylate is 10:(4-8):(6-9):(0.1-0.3):(0.3-0.5).

6. The low water absorption and voltage-resistant polyurethane acrylate adhesive according to claim 3, characterized in that: The weight ratio of the acrylate polymer to the polyurethane polymer is 1:(2-3).

7. The low water absorption and voltage-resistant polyurethane acrylate adhesive according to claim 3, characterized in that: The organosilicon monomer is vinyltriethoxysilane or / and methacryloyloxypropyltrimethoxysilane.

8. The low water absorption and voltage-resistant polyurethane acrylate adhesive according to claim 1, characterized in that: The active diluent is at least one of the following: neopentyl glycol glycidyl ether, diethylene glycol glycidyl ether, benzyl glycidyl ether, tert-butylphenol glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, n-octanol glycidyl ether, C12-14 alcohol glycidyl ether, phenyl glycidyl ether, o-cresol glycidyl ether, ethylene glycol glycidyl ether, butanediol glycidyl ether, hexanediol glycidyl ether, glycerol glycidyl ether, and trimethylolpropane glycidyl ether.

9. A method for preparing a low-water-absorption, voltage-resistant polyurethane acrylate adhesive as described in any one of claims 1-8, characterized in that, Includes the following steps: Polyurethane acrylate, multifunctional glycidyl ether epoxy resin, photoinitiator, water-repellent agent and reactive diluent are stirred evenly to obtain a low water absorption and voltage resistant polyurethane acrylate adhesive.

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