A UV / moisture dual-curing adhesive and its preparation method

Abstract

This invention belongs to the field of adhesive technology, specifically relating to a UV / moisture dual-curing adhesive and its preparation method. The dual-curing adhesive comprises the following raw materials in parts by weight: 75-90 parts polyurethane acrylate prepolymer, 10-25 parts curing agent, 1-5 parts photoinitiator, 0.01-0.1 parts organometallic catalyst, 0.1-0.3 parts polymerization inhibitor, 1-3 parts coupling agent, and 3-5 parts fumed silica. The polyurethane acrylate prepolymer is prepared by reacting diisocyanate, diol, and hydroxyl acrylate; the diol is a compound of hydrogenated hydroxyl-terminated polybutadiene and polyether diol; the curing agent has a specific molecular structure containing two isocyanates and one unsaturated double bond, which can respond to UV curing and moisture curing respectively, synergistically achieving photocuring and moisture curing with the polyurethane acrylate prepolymer, ensuring uniform overall curing of the adhesive, no uncured residue, improved mechanical properties, and low allergenicity; viscosity is adjusted by regulating the relative amounts of polyurethane acrylate prepolymer and curing agent.

Description

Technical Field

[0001] This invention belongs to the field of adhesive technology, specifically relating to a UV / moisture dual-curing adhesive and its preparation method. Background Technology

[0002] UV-moisture dual-curing adhesives refer to adhesives that simultaneously incorporate UV-curable groups (such as acrylate groups) and moisture-curable groups (such as isocyanate groups or siloxane groups) into the same adhesive system. After UV irradiation, the photoinitiator rapidly initiates the polymerization and cross-linking of the acrylate groups, achieving rapid curing. Subsequently, during room temperature storage, the isocyanate groups or siloxane groups in the system further react with moisture in the air, completing a slow post-curing process, thereby continuously increasing the cross-linking density and final bond strength of the system.

[0003] UV / moisture dual-curing adhesives combine the rapid positioning advantages of UV curing with the deep curing characteristics of moisture curing. They feature fast positioning speed, high curing efficiency, room temperature or low temperature curing capability, small curing equipment size, excellent bond strength, and compatibility with various substrates. These advantages enable them to meet the automated production needs of high-speed production lines, making them widely used in precision industries such as electronics, optical components, and biomedicine. For example, patent CN117567979B discloses a high-temperature resistant, thermally reversible, self-healing UV / moisture dual-curing conformal adhesive, comprising Y-type polyurethane modified acrylate oligomers, self-healing silicone modified acrylate oligomers, and acrylic reactive diluents as raw materials. Patent CN106590512B discloses an adhesive for a touch screen that is dual-cured by ultraviolet light and moisture, which is composed of the following raw materials in weight percentage: polyurethane acrylate: 50-75%; acrylic reactive diluent: 15-40%; silane coupling agent: 3-5%; photoinitiator: 1-5%; thixotropic agent: 1-5%; antioxidant: 0.5-1%; catalyst: 0.5-1%.

[0004] For UV / moisture dual-curing adhesives, acrylate reactive diluents are typically added. Their main function is to reduce adhesive viscosity and assist in the formation of a dense cross-linked network structure, thereby improving bond strength. However, acrylate reactive diluents containing double bonds generally suffer from high volatility and a noticeable irritating odor. More importantly, if the acrylate monomers and reactive diluents in the system are not completely cured, the residual active ingredients can easily cause allergic reactions on human skin, manifesting as symptoms such as itching, pain, erythema, or edema. This problem severely limits their application in wearable electronic products such as smart bracelets, smartwatches, wireless headphones, health monitoring devices, virtual reality glasses, and fitness trackers.

[0005] Therefore, it is necessary to develop a UV / moisture dual-curing adhesive that satisfies mechanical properties, adhesive properties, and aging resistance, while also being low in irritation, low in residue, low in allergens, and safe and environmentally friendly, in order to meet the requirements of long-term close contact use of wearable electronic products. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a UV / moisture-curing adhesive and its preparation method. The curing agent in the adhesive formulation of this invention has a specific molecular structure: containing two isocyanates and one unsaturated double bond, which can respond to UV curing and moisture curing respectively. It works synergistically with the polyurethane acrylate prepolymer to achieve both light curing and moisture curing, ensuring uniform overall curing of the adhesive with no uncured residue, improving mechanical properties, and possessing advantages such as low irritation, low residue, low allergenicity, and safety and environmental friendliness. The UV / moisture-curing adhesive does not contain acrylate reactive diluents; viscosity is adjusted by regulating the relative amounts of the polyurethane acrylate prepolymer and the curing agent.

[0007] To achieve the above objectives, the following technical solution is adopted:

[0008] A UV / moisture-curing adhesive comprises the following raw materials in parts by weight: 75-90 parts polyurethane acrylate prepolymer, 10-25 parts curing agent, 1-5 parts photoinitiator, 0.01-0.1 parts organometallic catalyst, 0.1-0.3 parts polymerization inhibitor, 1-3 parts coupling agent, and 3-5 parts fumed silica. The polyurethane acrylate prepolymer is prepared by reacting diisocyanate, diol, and hydroxyl acrylate; the diol is a compound of hydrogenated hydroxyl-terminated polybutadiene and polyether diol; and the curing agent has the following structural formula (Formula I):

[0009] Formula I

[0010] Where a and b are independently selected from integers from 2 to 5, and R1 is independently one of H and CH3.

[0011] The curing agent is prepared by a method comprising the following steps:

[0012] 1) The amino protection reaction of NH-bis(polyethylene glycol-hydroxy) with an amino protecting agent is used to obtain Boc-N-bis(polyethylene glycol-hydroxy), and the reaction of Boc-N-bis(polyethylene glycol-hydroxy) with benzoyl isocyanate isocyanate compound is obtained.

[0013] 2) Deprotect the Boc-N-diisocyanate compound, and react the resulting deprotected N-diisocyanate compound with an unsaturated acyl chloride compound to obtain a curing agent.

[0014] In step 1), the NH-bis(polyethylene glycol-hydroxy) is selected from one or more of NH-bis(monopolyethylene glycol-hydroxy), NH-bis(dipolyethylene glycol-hydroxy), NH-bis(tripolyethylene glycol-hydroxy), and NH-bis(tetrapolyethylene glycol-hydroxy).

[0015] In step 1), the amino protecting agent is ditert-butyl dicarbonate.

[0016] Furthermore, the molar ratio of NH-bis(polyethylene glycol-hydroxy) and ditert-butyl dicarbonate is 1:1.1-1.5.

[0017] Further, the amino protection reaction specifically involves dissolving NH-bis(polyethylene glycol-hydroxy) in an organic solvent, adding di-tert-butyl dicarbonate and an acid-binding agent, mixing well, and reacting at a controlled temperature to obtain Boc-N-bis(polyethylene glycol-hydroxy).

[0018] Furthermore, the temperature-controlled reaction is carried out at 20-40℃ for 12-24 hours. The organic solvent is selected from one or more combinations of methanol, ethanol, and tetrahydrofuran. The acid-binding agent is selected from one or more combinations of triethylamine, 4-dimethylaminopyridine, and pyridine. The molar ratio of di-tert-butyl dicarbonate to the acid-binding agent is 1:1-1.5.

[0019] Furthermore, after the temperature-controlled reaction is completed, the process includes vacuum distillation concentration, resolution, washing the organic phase with 3-5 wt% citric acid and saturated sodium bicarbonate solution until the pH of the separated aqueous phase is 7, washing with saturated brine, drying, and vacuum distillation concentration. The solvent for resolution is selected from one or more combinations of ethyl acetate, tetrahydrofuran, diethyl ether, and isopropyl ether.

[0020] In step 1), the benzoyl isocyanate compound is selected from one or a combination of two of p-benzoyl isocyanate and 3-isocyanoxybenzoyl chloride. The molar ratio of the Boc-N-bis(polyethylene glycol-hydroxy) and benzoyl isocyanate compounds is 1:2.1-2.2.

[0021] In step 1), the reaction of Boc-N-bis(polyethylene glycol-hydroxy) with benzoyl isocyanate chloride compound specifically involves dissolving Boc-N-bis(polyethylene glycol-hydroxy) and acid-binding agent in an anhydrous organic solvent, and then adding the benzoyl isocyanate chloride compound solution dropwise to react and obtain Boc-N-bisisocyanate compound.

[0022] Further, in step 1), the molar ratio of the benzoyl isocyanate chloride compound and the acid-binding agent is 1:1-1.5. The acid-binding agent is selected from one or more combinations of triethylamine, 4-dimethylaminopyridine, and pyridine. The anhydrous organic solvent is selected from one or more combinations of anhydrous toluene, anhydrous dichloromethane, anhydrous ethyl acetate, and anhydrous tetrahydrofuran. The concentration of the benzoyl isocyanate chloride compound solution is 0.5-1 mol / L. The solvent of the benzoyl isocyanate chloride compound solution is the same as that of the anhydrous organic solvent. The benzoyl isocyanate chloride compound solution is added dropwise over 30-120 minutes. The reaction is carried out under a dry, inert gas atmosphere, at -5 to 5°C, and with stirring at 500-1000 rpm for 1-3 hours.

[0023] In step 1), after the reaction of Boc-N-bis(polyethylene glycol-hydroxy) with benzoyl isocyanate chloride is completed, the process further includes filtration, vacuum distillation, and column chromatography post-treatment. The column chromatography eluent is a mixture of petroleum ether and ethyl acetate with a volume ratio of 2-4:1, preferably 3-4:1.

[0024] Further, in step 2), the deprotection is performed by adding the Boc-N-diisocyanate compound to a trifluoroacetic acid solution for a deprotection reaction to obtain the deprotected product N-diisocyanate compound; the deprotection reaction conditions are 20-40℃ and 1-3 h. The molar ratio of the Boc-N-diisocyanate compound to trifluoroacetic acid is 1:5-10. The concentration of the trifluoroacetic acid solution is 2.5-4 mol / L. The solvent of the trifluoroacetic acid solution is selected from one or more combinations of anhydrous dichloromethane, anhydrous tetrahydrofuran, anhydrous DMF, and anhydrous NMP.

[0025] Step 2) further includes the following post-treatment operations after the deprotection reaction: vacuum distillation, resolution, and recrystallization. The solvent for resolution is selected from one or more combinations of anhydrous tetrahydrofuran, anhydrous diethyl ether, anhydrous methyl tert-butyl ether, and anhydrous ethyl acetate.

[0026] In step 2), the molar ratio of the N-diisocyanate compound to the unsaturated acyl chloride compound is 1:1.05-1.08. The reaction of the N-diisocyanate compound and the unsaturated acyl chloride compound is carried out under a dry, inert gas atmosphere, at -5 to 5°C, and with stirring at 500-1000 rpm for 1-3 hours. After the reaction of the N-diisocyanate compound and the unsaturated acyl chloride compound is completed, further steps include filtration, vacuum distillation, and column chromatography post-treatment. The column chromatography eluent is a mixture of petroleum ether and ethyl acetate with a volume ratio of 1-3:1, preferably 1-2:1.

[0027] In step 2), the reaction of the obtained deprotected product N-diisocyanate compound with the unsaturated acyl chloride compound is specifically as follows: dissolve the N-diisocyanate compound and the acid-binding agent in an organic solvent, add the unsaturated acyl chloride compound solution dropwise to react, and obtain the curing agent.

[0028] Further, the molar ratio of the unsaturated acyl chloride compound to the acid-binding agent is 1:1.1-1.5. The concentration of the unsaturated acyl chloride compound solution is 0.8-1.5 mol / L. The unsaturated acyl chloride compound solution is added dropwise over 30-120 minutes. The solvent of the unsaturated acyl chloride compound solution is selected from one or more combinations of anhydrous toluene, anhydrous dioxane, and anhydrous tetrahydrofuran. The acid-binding agent is selected from one or more combinations of triethylamine, 4-dimethylaminopyridine, and pyridine. The organic solvent is selected from one or more combinations of anhydrous toluene, anhydrous dioxane, and anhydrous tetrahydrofuran.

[0029] The molar ratio of hydrogenated hydroxyl-terminated polybutadiene to polyether diol is 1:1-3.

[0030] The hydrogenated hydroxyl-terminated polybutadiene has a number-average molecular weight of 1500-3500. The polyether diol has a number-average molecular weight of 800-1500.

[0031] The molar ratio of the diisocyanate, diol, and hydroxyacrylate is 1.4-1.7:1:0.4-0.7.

[0032] The diisocyanate is selected from one or more combinations of 1,6-hexylene diisocyanate, isophorone diisocyanate, trimethyl 1,6-hexylene diisocyanate, hexamethylene diisocyanate, 4,4'-diphenylmethane diisocyanate, phenyl diisocyanate, p-phenylene diisocyanate, naphthyl diisocyanate, and tetramethylxylene diisocyanate.

[0033] The hydroxyacrylate is selected from one or more of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, and hydroxypropyl acrylate.

[0034] The polyurethane acrylate prepolymer is prepared by a method comprising the following steps:

[0035] Diisocyanate and catalyst were mixed, and diol was added and heated to react. Hydroxy acrylate and polymerization inhibitor were added and the temperature was controlled to react, thus obtaining polyurethane acrylate prepolymer.

[0036] The heating reaction conditions are 40-60℃ for 0.5-1 h. The temperature control reaction conditions are 70-80℃ for 2-4 h. The catalyst is selected from one or more of organotin catalysts, organozinc catalysts, and organobismuth catalysts. The organotin catalyst is selected from one or more of dibutyltin dilaurate, stannous octanoate, di(dodecyl sulfide)dibutyltin, dibutyltin diacetate, dibutyltin dibutyrate, and dibutyltin dioleate. The organobismuth catalyst is selected from one or more of bismuth neodecanoate, bismuth laurate, bismuth isooctanoate, and bismuth naphthenate. The organozinc catalyst is selected from one or more of zinc isooctanoate, zinc neodecanoate, and zinc naphthenate. The polymerization inhibitor is selected from one or more of p-hydroxyanisole, hydroquinone, p-benzoquinone, and anthraquinone. The amount of catalyst used is 0.1-1 wt‰ of the sum of the masses of diisocyanate, diol, and hydroxyacrylate. The amount of the polymerization inhibitor is 0.1-1 wt‰ of the sum of the masses of diisocyanate, diol, and hydroxyacrylate.

[0037] The photoinitiator is selected from one or a combination of two of the following: benzoin and its derivatives, benzoyl and its derivatives, acetophenone derivatives, α-hydroxy ketone derivatives, α-amino ketone derivatives, benzoyl carbamates, acylphosphine oxides, and sulfur-containing photoinitiators.

[0038] The organometallic catalyst is selected from one or more combinations of organotin catalysts, organozinc catalysts, and organobismuth catalysts. The organotin catalyst is selected from one or more combinations of dibutyltin dilaurate, stannous octanoate, di(dodecyl sulfide)dibutyltin, dibutyltin diacetate, dibutyltin dibutyrate, and dibutyltin dioleate. The organobismuth catalyst is selected from one or more combinations of bismuth neodecanoate, bismuth laurate, bismuth isooctanoate, and bismuth naphthenate. The organozinc catalyst is selected from one or more combinations of zinc isooctanoate, zinc neodecanoate, and zinc naphthenate.

[0039] The polymerization inhibitor is selected from one or a combination of two of p-hydroxyanisole, hydroquinone, p-benzoquinone, and anthraquinone.

[0040] The coupling agent is selected from one or a combination of two of epoxy silane coupling agents and alkenyl silane coupling agents.

[0041] The epoxy silane coupling agent is selected from one or more combinations of 2-(3,4-epoxycyclohexyl)methyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, (3-epoxypropoxypropyl)dimethylethoxysilane, 3-[(2,3)-epoxypropoxy]propylmethyldimethoxysilane, 3-glycidyl etheroxypropyltriethoxysilane, and 3-glycidyl etheroxypropylmethyldiethoxysilane. The alkenyl silane coupling agent is selected from one or more combinations of allyltrimethoxysilane, allyltriethoxysilane, (acrylate oxymethyl)methyldimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 5-hexenyltrimethoxysilane, methylvinyldimethoxysilane, methylvinyldiethoxysilane, and 5-hexenyltriethoxysilane.

[0042] The fumed silica has an average particle size of 5-50 nm and a specific surface area of ​​100-300 m². 2 / g.

[0043] The UV / moisture-curing adhesive may also include 0.1-3 parts of additives, wherein the additives are selected from one or more combinations of leveling agents, antioxidants, and UV absorbers.

[0044] The leveling agent is selected from one or a combination of two of the following: silicone leveling agents and fluorocarbon leveling agents.

[0045] The present invention also provides a method for preparing the above-mentioned UV / moisture-curing adhesive, comprising the following steps:

[0046] A UV / moisture-curing adhesive is obtained by mixing polyurethane acrylate prepolymer, curing agent, photoinitiator, organometallic catalyst, polymerization inhibitor, and coupling agent under light-proof and moisture-proof conditions.

[0047] Compared with the prior art, the beneficial effects of the present invention are:

[0048] First, the curing agent in the curing adhesive formulation of this invention has a specific molecular structure: it contains two isocyanates and one unsaturated double bond, which can respond to UV curing and moisture curing respectively. It works synergistically with the polyurethane acrylate prepolymer to achieve light curing and moisture curing, ensuring that the adhesive is cured uniformly with no uncured residue, improving mechanical properties, and has the advantages of low irritation, low residue, low allergenicity, safety and environmental protection.

[0049] II. The UV / moisture curing adhesive of this invention does not contain acrylate reactive diluents, and viscosity is adjusted by regulating the relative amounts of polyurethane acrylate prepolymer and curing agent. Detailed Implementation

[0050] The present invention will be further described below with reference to specific embodiments, but is not limited to the contents of the specification. Unless otherwise specified, all "parts" mentioned in the embodiments of the present invention are parts by weight. All reagents used are commercially available in the art.

[0051] NH-bis(monopolyethylene glycol-hydroxy) (CAS: 54384-47-3), NH-bis(dipolyethylene glycol-hydroxy) (CAS: 25743-12-8), NH-bis(tripolyethylene glycol-hydroxy) (CAS: 63721-14-2), and NH-bis(tetrapolyethylene glycol-hydroxy) (CAS: 63721-06-2) are all from Shanghai Aladdin.

[0052] Hydrogenated hydroxyl-terminated polybutadiene GI3000 has a number-average molecular weight of 3100 and is sourced from Japan's Soda Corporation.

[0053] Hydrogenated hydroxyl-terminated polybutadiene GI1000 has a number-average molecular weight of 1500 and is sourced from Japan's Soda Corporation.

[0054] PEG800, with a number average molecular weight of 800, is sourced from Haian Petrochemical.

[0055] PEG1500, with a number average molecular weight of 1500, is sourced from Haian Petrochemical.

[0056] Example 1

[0057] 1) Dissolve 1 mol of NH-bis(polyethylene glycol-hydroxy) in 2 L of tetrahydrofuran, add 1.1 mol of di-tert-butyl dicarbonate and 1.1 mol of triethylamine, mix well, and react at 20 °C for 24 h. After the reaction is completed, concentrate by vacuum distillation at 30 °C to remove the solvent and triethylamine. The concentrate is redissolved in ethyl acetate, washed with 5 wt% citric acid, and the organic phase is washed with saturated sodium bicarbonate solution until the pH of the separated aqueous phase is 7. The organic phase is washed with saturated brine, dried with anhydrous sodium sulfate, filtered, and the filtrate is concentrated by vacuum distillation to obtain Boc-N-bis(polyethylene glycol-hydroxy).

[0058] 2) Dissolve 1 mol of Boc-N-bis(polyethylene glycol-hydroxy) and 2.1 mol of triethylamine in 4.5 L of anhydrous ethyl acetate, and add 4.2 L of 0.5 mol / L benzoyl isocyanate solution (solvent is anhydrous ethyl acetate) dropwise. After the addition is completed in 60 min, react for 3 h under a dry nitrogen atmosphere, at -5 °C and with stirring at 800 rpm. After the reaction is completed, filter, remove the solvent and triethylamine by vacuum distillation at 25 °C, and then perform column chromatography. The eluent for column chromatography is a mixture of petroleum ether and ethyl acetate in a volume ratio of 4:1 to obtain the Boc-N-bisisocyanate compound.

[0059] 3) Add 1 mol of Boc-N-diisocyanate compound to 2 L of 2.5 mol / L trifluoroacetic acid solution (solvent is anhydrous ethyl acetate), and deprotect the compound at 20 °C for 3 h. After the reaction is completed, remove the solvent and trifluoroacetic acid by vacuum distillation at 20 °C, and recrystallize the compound in anhydrous ethyl acetate to obtain the deprotected product N-diisocyanate compound.

[0060] 4) Dissolve 1 mol of N-diisocyanate compound and 1.155 mol of triethylamine in 3 L of anhydrous dioxane, and add 1.05 L of 1 mol / L acryloyl chloride solution (solvent is anhydrous dioxane) dropwise. After the addition is completed in 60 min, stir the mixture at 800 rpm for 3 h under a dry nitrogen atmosphere at -5 °C. After the reaction is completed, filter the mixture, remove the solvent and triethylamine from the filtrate by vacuum distillation at 27 °C, and then perform column chromatography. The eluent for column chromatography is a mixture of petroleum ether and ethyl acetate in a volume ratio of 2:1 to obtain the curing agent.

[0061] 5) Mix 1.4 mol of 4,4'-diphenylmethane diisocyanate, 1 wt‰ of the mass of 4,4'-diphenylmethane diisocyanate, hydrogenated hydroxyl-terminated polybutadiene GI3000, PEG800, hydroxyethyl acrylate, and 1 wt‰ of dibutyltin dilaurate. Add 1 mol of a diol prepared by a 1:1 molar ratio of hydrogenated hydroxyl-terminated polybutadiene GI3000 and PEG800 and heat to 40°C for 1 h. Add 0.4 mol of hydroxyethyl acrylate and 0.3 wt‰ of the polymerization inhibitor p-benzoquinone, and control the temperature at 80°C for 4 h to obtain a polyurethane acrylate prepolymer.

[0062] 6) Add 75 kg of polyurethane acrylate prepolymer, 25 kg of curing agent, 5 kg of photoinitiator α,α′-dimethylbenzoyl ketal, 0.1 kg of dibutyltin dilaurate, 0.1 kg of p-benzoquinone, 3 kg of 3-glycidyl ether oxypropyltriethoxysilane, 0.3 kg of BYK-306, and 3 kg of fumed silica AEROSIL R202 to a light-proof mixing vessel. After evacuation, fill the vessel with dry nitrogen and stir at 500 rpm for 1 hour. Then, degas the vessel under vacuum at -0.09 MPa for 20 minutes and discharge the material to obtain the UV / moisture-curing adhesive.

[0063] Example 2

[0064] The rest is the same as in Example 1, except that in step 1), NH-bis(polyethylene glycol-hydroxy) is replaced with an equimolar amount of NH-bis(polyethylene glycol-hydroxy).

[0065] Example 3

[0066] The rest is the same as in Example 1, except that in step 1), NH-bis(monopolyethylene glycol-hydroxy) is replaced with an equimolar amount of NH-bis(tetraethylene glycol-hydroxy).

[0067] Example 4

[0068] The rest is the same as in Example 1, except that in step 6), the amount of polyurethane acrylate prepolymer is 90 kg and the amount of curing agent is 10 kg.

[0069] Example 5

[0070] The rest is the same as in Example 1, except that in step 5), the diol is composed of hydrogenated hydroxyl-terminated polybutadiene GI3000 and PEG800 in a molar ratio of 1:3.

[0071] Example 6

[0072] The rest is the same as in Example 1, except that in step 5), the diol is composed of hydrogenated hydroxyl-terminated polybutadiene GI1000 and PEG1500 in a molar ratio of 1:1.

[0073] Example 7

[0074] 1) Dissolve 1 mol of NH-bis(polyethylene glycol-hydroxy) in 2 L of tetrahydrofuran, add 1.5 mol of di-tert-butyl dicarbonate and 1.1 mol of triethylamine, mix well, and react at 20 °C for 24 h. After the reaction is completed, concentrate by vacuum distillation at 30 °C to remove the solvent and triethylamine. The concentrate is redissolved in ethyl acetate, washed with 5 wt% citric acid, and the organic phase is washed with saturated sodium bicarbonate solution until the pH of the separated aqueous phase is 7. The organic phase is washed with saturated brine, dried with anhydrous sodium sulfate, filtered, and the filtrate is concentrated by vacuum distillation to obtain Boc-N-bis(polyethylene glycol-hydroxy).

[0075] 2) Dissolve 1 mol of Boc-N-bis(polyethylene glycol-hydroxy) and 2.1 mol of triethylamine in 4.5 L of anhydrous ethyl acetate, and add 4.2 L of 0.5 mol / L benzoyl isocyanate solution (solvent is anhydrous ethyl acetate) dropwise. After the addition is completed in 60 min, react for 3 h under a dry nitrogen atmosphere, 0 °C and stirring at 800 rpm. After the reaction is completed, filter, remove the solvent and triethylamine by vacuum distillation at 25 °C, and then perform column chromatography. The eluent for column chromatography is a mixture of petroleum ether and ethyl acetate in a volume ratio of 3:1 to obtain the Boc-N-bisisocyanate compound.

[0076] 3) Add 1 mol of Boc-N-diisocyanate compound to 2 L of 2.5 mol / L trifluoroacetic acid solution (solvent is anhydrous ethyl acetate), and deprotect the compound at 20 °C for 3 h. After the reaction is completed, remove the solvent and trifluoroacetic acid by vacuum distillation at 20 °C, and recrystallize the compound in anhydrous ethyl acetate to obtain the deprotected product N-diisocyanate compound.

[0077] 4) Dissolve 1 mol of N-diisocyanate compound and 1.188 mol of triethylamine in 3 L of anhydrous dioxane, and add 1.08 L of 1 mol / L methacryloyl chloride solution (solvent is anhydrous dioxane) dropwise. After the addition is completed in 60 min, stir the mixture at 800 rpm for 3 h under a dry nitrogen atmosphere at -5 °C. After the reaction is completed, filter the mixture, remove the solvent and triethylamine from the filtrate by vacuum distillation at 27 °C, and then perform column chromatography. The eluent for column chromatography is a mixture of petroleum ether and ethyl acetate in a volume ratio of 1:1 to obtain the curing agent.

[0078] 5) Mix 1.7 mol of hexamethylene diisocyanate with 1 wt‰ of dibutyltin dilaurate (based on the mass of hexamethylene diisocyanate, hydrogenated hydroxyl-terminated polybutadiene GI3000, PEG800, hydroxypropyl methacrylate, and hydrogenated hydroxyl-terminated polybutadiene GI3000 and PEG800). Add 1 mol of diol (based on the molar ratio of hydrogenated hydroxyl-terminated polybutadiene GI3000 and PEG800 of 1:1) and heat to 40°C for 1 h. Add 0.7 mol of hydroxypropyl methacrylate and 0.3 wt‰ of p-benzoquinone (based on the mass of hexamethylene diisocyanate, hydrogenated hydroxyl-terminated polybutadiene GI3000, PEG800, hydroxypropyl methacrylate, and hydrogenation inhibitor) and react at 80°C for 4 h to obtain polyurethane acrylate prepolymer.

[0079] 6) Add 75 kg of polyurethane acrylate prepolymer, 10 kg of curing agent, 5 kg of photoinitiator α,α′-dimethylbenzoyl ketal, 0.1 kg of dibutyltin dilaurate, 0.1 kg of p-benzoquinone, 3 kg of 3-glycidyl ether oxypropyltriethoxysilane, 0.3 kg of BYK-306, and 3 kg of fumed silica AEROSIL R202 to a light-proof mixing vessel. After evacuation, fill the vessel with dry nitrogen and stir at 500 rpm for 1 hour. Then, degas the vessel under vacuum at -0.09 MPa for 20 minutes and discharge the material to obtain the UV / moisture-curing adhesive.

[0080] Comparative Example 1

[0081] The rest is the same as in Example 1, except that in step 5), all the diols are hydrogenated hydroxyl-terminated polybutadiene GI3000.

[0082] Comparative Example 2

[0083] The rest is the same as in Example 1, except that in step 5), all the diols are PEG800.

[0084] The adhesives prepared in the above embodiments and comparative examples were subjected to the following performance tests:

[0085] Tensile shear strength: The tensile shear strength of adhesives was determined according to standard GB / T7124-2008. A shear sheet of PC to aluminum plate (Al) with an overlap area of ​​25.4 mm × 12.7 mm × 0.1 mm was prepared, and then tested using an ultraviolet light source (365 nm, light intensity 3000 mJ / cm²). 2 Irradiation curing for 4 seconds, after which the product is placed in a constant temperature and humidity room at 23±2℃ and 50±10%RH for 7 days under absolute light protection to fully cure, and the tensile shear strength B0 is tested.

[0086] High temperature and high humidity resistance test: The above tensile shear strength test specimens were placed in a constant temperature and humidity chamber, with the temperature and humidity set at 85℃@85%RH. After 250h, the specimens were removed and placed at room temperature to test the shear strength B1. The strength attenuation rate ε compared to the complete UV / moisture curing was calculated. ε = B0 - B1 / B0 × 100%. The smaller the strength attenuation rate ε, the better the high temperature and high humidity resistance of the adhesive after curing.

[0087] Viscosity: Brookfield rotational viscometer, average value obtained from three tests.

[0088] Sensitization test: Skin sensitization test was conducted in accordance with ISO10993-10:2023. Level 0 indicates no sensitization reaction, and levels 1-3 correspond to mild to severe sensitization, respectively.

[0089] Table 1 Performance Tests

[0090]

[0091] As shown in Table 1, the adhesive prepared by this invention has the advantages of low irritation, low residue, and low allergenicity. Furthermore, after complete curing, its tensile shear strength reaches 10.4-13.2 MPa, and the strength loss rate after high-temperature and high-humidity aging is controlled at 0.7-2.9%. The comparative examples demonstrate that hydrogenated hydroxyl-terminated polybutadiene, polyether diol, and curing agent have a significant synergistic effect in improving tensile shear strength.

[0092] The above detailed description is a specific description of one of the feasible embodiments of the present invention. This embodiment is not intended to limit the patent scope of the present invention. All equivalent implementations or modifications that do not depart from the present invention should be included within the scope of the technical solution of the present invention.

Claims

1. A UV / moisture-curing adhesive, characterized in that, The raw materials comprise the following parts by weight: 75-90 parts polyurethane acrylate prepolymer, 10-25 parts curing agent, 1-5 parts photoinitiator, 0.01-0.1 parts organometallic catalyst, 0.1-0.3 parts polymerization inhibitor, 1-3 parts coupling agent, and 3-5 parts fumed silica. The polyurethane acrylate prepolymer is prepared by reacting diisocyanate, diol, and hydroxyl acrylate; the diol is a compound of hydrogenated hydroxyl-terminated polybutadiene and polyether diol; the curing agent has the following structural formula (Formula I): Formula I Where a and b are independently selected from integers from 2 to 5, and R1 is independently one of H and CH3.

2. The UV / moisture-curing adhesive according to claim 1, characterized in that, The curing agent is prepared by a method comprising the following steps: 1) The amino protection reaction of NH-bis(polyethylene glycol-hydroxy) with an amino protecting agent is used to obtain Boc-N-bis(polyethylene glycol-hydroxy), and the reaction of Boc-N-bis(polyethylene glycol-hydroxy) with benzoyl isocyanate isocyanate compound is obtained. 2) Deprotect the Boc-N-diisocyanate compound, and react the resulting deprotected N-diisocyanate compound with an unsaturated acyl chloride compound to obtain a curing agent.

3. The UV / moisture-curing adhesive according to claim 2, characterized in that, In step 1), the NH-bis(polyethylene glycol-hydroxy) is selected from one or more of NH-bis(monopolyethylene glycol-hydroxy), NH-bis(dipolyethylene glycol-hydroxy), NH-bis(tripolyethylene glycol-hydroxy), and NH-bis(tetrapolyethylene glycol-hydroxy); the amino protecting agent is di-tert-butyl dicarbonate; and the benzoyl isocyanate chloride compound is selected from one or a combination of two of p-benzoyl isocyanate chloride and 3-isocyanoxybenzoyl chloride.

4. The UV / moisture-curing adhesive according to claim 2, characterized in that, In step 1), the reaction between Boc-N-bis(polyethylene glycol-hydroxy) and benzoyl isocyanate chloride compound specifically involves dissolving Boc-N-bis(polyethylene glycol-hydroxy) and an acid-binding agent in an anhydrous organic solvent, and then adding the benzoyl isocyanate chloride compound solution dropwise to obtain Boc-N-bisisocyanate compound; the molar ratio of Boc-N-bis(polyethylene glycol-hydroxy) and benzoyl isocyanate chloride compound is 1:2.1-2.

2.

5. The UV / moisture-curing adhesive according to claim 2, characterized in that, In step 2), the reaction of the obtained deprotected product N-diisocyanate compound with the unsaturated acyl chloride compound is specifically as follows: dissolving the N-diisocyanate compound and the acid-binding agent in an organic solvent, and adding the unsaturated acyl chloride compound solution dropwise to react and obtain the curing agent; the molar ratio of the N-diisocyanate compound to the unsaturated acyl chloride compound is 1:1.05-1.

08.

6. The UV / moisture-curing adhesive according to claim 1, characterized in that, The molar ratio of hydrogenated hydroxyl-terminated polybutadiene to polyether diol is 1:1-3; the number-average molecular weight of the hydrogenated hydroxyl-terminated polybutadiene is 1500-3500; and the number-average molecular weight of the polyether diol is 800-1500.

7. The UV / moisture-curing adhesive according to claim 1, characterized in that, The molar ratio of the diisocyanate, diol, and hydroxyacrylate is 1.4-1.7:1:0.4-0.7; the diisocyanate is selected from one or more combinations of 1,6-hexylene diisocyanate, isophorone diisocyanate, trimethyl-1,6-hexylene diisocyanate, hexamethylene diisocyanate, 4,4'-diphenylmethane diisocyanate, phenyl diisocyanate, p-phenylene diisocyanate, naphthyl diisocyanate, and tetramethylxylene diisocyanate; the hydroxyacrylate is selected from one or more combinations of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, and hydroxypropyl acrylate.

8. The UV / moisture-curing adhesive according to claim 1, characterized in that, The polyurethane acrylate prepolymer is prepared by a method comprising the following steps: Diisocyanate and catalyst were mixed, and diol was added and heated to react. Hydroxy acrylate and polymerization inhibitor were added and the temperature was controlled to react, thus obtaining polyurethane acrylate prepolymer.

9. The UV / moisture-curing adhesive according to claim 1, characterized in that, The coupling agent is selected from one or a combination of two of epoxy-based silane coupling agents and alkenyl-containing silane coupling agents; the primary particles of the fumed silica have an average particle size of 5-50 nm and a specific surface area of ​​100-300 m². 2 / g.

10. A method for preparing the UV / moisture-curing adhesive according to any one of claims 1-9, characterized in that, Includes the following steps: A UV / moisture-curing adhesive is obtained by mixing polyurethane acrylate prepolymer, curing agent, photoinitiator, organometallic catalyst, polymerization inhibitor, coupling agent, and fumed silica under light-proof and moisture-proof conditions.

Images