A supramolecular host-guest photoinitiator with adjustable curing rate and adhesive

Abstract

This invention discloses a supramolecular host-guest photoinitiator with adjustable curing rate and an epoxy adhesive. The supramolecular host-guest photoinitiator comprises a supramolecular host compound and a guest photoinitiator encapsulated therein. The supramolecular host compound has a macrocyclic structure with 2-30 repeating units, and the guest photoinitiator includes a cationic photoinitiator. In the supramolecular host-guest photoinitiator, the molar ratio of the supramolecular host compound to the guest photoinitiator is (0.8-1.5):1, and the mass percentage of carbon and hydrogen is (40-75):(3-8). The UV epoxy adhesive, comprising the supramolecular host-guest photoinitiator with adjustable curing rate, forms a delayed curing window after UV light irradiation. The adhesive exhibits excellent flow and coating properties. After the window period, the adhesive can continue to polymerize and cure independently of light irradiation, and the curing rate can be adjusted by controlling heat input.

Description

[0001] This application is a divisional application of the invention patent application with application number 202511177318.1 and invention title "Adjustable curing rate supramolecular host-guest photoinitiator and epoxy adhesive". Technical Field

[0002] This invention relates to the field of adhesives, and more particularly to a supramolecular host-guest photoinitiator with adjustable curing rate and an epoxy adhesive, as well as a method for preparing the epoxy adhesive and its application. Background Technology

[0003] In recent decades, UV-curable epoxy adhesives have been widely used in fields such as precision electronic device packaging due to their significant advantages, including fast curing speed, ease of use, and high bonding strength. However, when the substrate to be bonded cannot be penetrated by ultraviolet light, such as when the adhesive is applied to a non-transparent substrate or a substrate with added UV absorbers, the photoinitiator cannot be activated by light, preventing successful UV curing and greatly limiting the application scenarios of UV-curable adhesives.

[0004] To address the aforementioned challenges, those skilled in the art have proposed solutions combining UV with other curing methods, such as UV / moisture dual curing and UV / heat dual curing. However, these solutions all have their own drawbacks, such as poor compatibility between material components, difficulty in dispersion, insufficient bonding strength, limitations on material types to avoid unwanted side reactions, and inapplicability to environments with special construction requirements. Another relatively more effective solution is to develop delayed-curing adhesives that do not cure immediately after light exposure, but only begin curing after the substrate is joined. In recent years, based on specific formulation designs, resin structure designs, and the selection of photoinitiators, several UV delayed-curing adhesives have been developed. For example, invention patent application CN118307767A discloses an epoxy resin UV delayed-curing agent, which, when used to prepare resin compositions for display element encapsulation, exhibits excellent properties such as delayed curing, strong moisture barrier ability, and strong adhesion. When applied to the encapsulation of display elements, it can provide better protection for the display elements. This invention achieves a certain delay time through structural design of the epoxy compound. For example, invention patent CN115895549B discloses a UV-delayed curing adhesive for sealing cylindrical batteries, its preparation method, and its application. This adhesive includes components such as naphthalene-type epoxy resin, bridged-ring epoxy resin, toughening agent, reactive diluent, and photoinitiator. This invention obtains a UV-delayed curing adhesive by compounding fast-curing epoxy resin and slow-curing epoxy resin. The above solutions all focus on modifying or compounding epoxy resins as their main research direction, achieving relatively good control of curing rate and delayed curing. However, these strategies are only effective for certain specific formulation ranges. When the formulation contains highly reactive resins (such as alicyclic epoxy resins), the system will still cure rapidly. Therefore, the universality of the above solutions is still insufficient.

[0005] In summary, how to provide a comprehensive UV-delayed curing solution that can achieve the delay effect for most adhesive formulations, and allow for manual control of the delay window and the entire curing process according to actual process requirements, has become a pressing technical problem to be solved in this field. Summary of the Invention

[0006] To address the shortcomings of the existing technologies, this invention provides a supramolecular host-guest photoinitiator with adjustable curing rate and a UV epoxy adhesive, along with their preparation method and applications. The supramolecular host-guest photoinitiator, comprising a supramolecular host compound and a guest photoinitiator encapsulated therein, is added to an epoxy adhesive composition to obtain a UV epoxy adhesive with adjustable curing rate. This adhesive exhibits significant delayed curing characteristics after light exposure, and based on different macroring sizes, the initiator can provide an adjustable delay window. After complete curing, the cured system possesses advantages such as high adhesion and good moisture barrier properties.

[0007] In a first aspect, the present invention provides a supramolecular host-guest photoinitiator with adjustable curing rate, comprising a supramolecular host compound and a guest photoinitiator encapsulated therein, wherein the supramolecular host compound has a macrocyclic structure with 2-30 repeating units, and the guest photoinitiator comprises a cationic photoinitiator. In the supramolecular host-guest photoinitiator, the molar ratio of the supramolecular host compound to the guest photoinitiator is (0.8-1.5):1, and the mass percentage of carbon and hydrogen is (40-75):(3-8).

[0008] Supramolecular host compounds are a class of macrocyclic compounds that can form relatively stable host-guest complexes with some small molecule guest compounds through non-covalent interactions such as electrostatics, hydrogen bonding, and π-π. Based on this, the present invention prepares a series of photoinitiators with supramolecular host-guest structures. Upon exposure to UV light, the guest photoinitiator molecules undergo photolysis to generate active species that induce the polymerization of epoxy cationic compounds. However, unlike traditional photoinitiators, the active species is initially bound by the macrocyclic host molecule and cannot efficiently induce polymerization. Therefore, a delayed window period, such as 3-30 min, preferably 5-20 min, can be provided in the early stages of the reaction. Due to the existence of chemical reaction equilibrium, a small amount of active species induces slow polymerization. When polymerization reaches a certain level and / or the system temperature rises, the reaction equilibrium is broken, and the active species is released, thereby accelerating the polymerization rate.

[0009] Regarding the specific types of cationic photoinitiators, different photoinitiators can be selected based on the polymerization mechanism of different monomers. These include, but are not limited to, iodonium salts, thiodonium salts, ferrocene salts, quaternary ammonium salts, diazonium salts, phosphonium salts, bromonium salts, chloride salts, and any initiator capable of generating cations under UV light irradiation. The inclusion of the photoinitiator by the supramolecular host compound effectively provides a sustained-release effect, exhibiting good overall versatility in delayed curing. Furthermore, by selecting the type and amount of the supramolecular host compound and guest photoinitiator, the delayed curing window can be effectively adjusted according to the application requirements.

[0010] Furthermore, the supramolecular host compound has the structure shown in Formula I:

[0011] R1 is an independent repeating unit selected from at least one main structure of cyclophenylene, crown ether, calixarene, columnar aromatics, cyclodextrin, and cucurbituril, where n is a positive integer selected from 2 to 30; R2 and Ra independently include at least one of the following: hydrogen atom, substituted or unsubstituted alkyl group, substituted or unsubstituted heterochain alkyl group, substituted or unsubstituted aromatic ring group, substituted or unsubstituted alkoxy group, substituted or unsubstituted alkylthio group, substituted or unsubstituted cycloalkyl group, halogen atom, hydroxyl group, carbonyl group, carboxyl group, ester group, acyl group, amino group, mercapto group, and carboxyl salt. * is the bonding site between Ra and the macrocyclic structure.

[0012] Furthermore, Ra includes the structure shown in Formula II:

[0013] Rb includes at least one of hydrogen atom, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C1-C10 heterochain alkyl, and substituted or unsubstituted C1-C6 alkoxy. R5 is independently selected from one of the following groups: .

[0014] This invention not only employs a supramolecular host compound to encapsulate and slow-release the guest photoinitiator therein, but also further extends the delayed curing window by introducing reactive functional groups (such as epoxy group R5) onto the macrocycle of the supramolecular host compound. Furthermore, by utilizing the highly reactive functional groups and their reactivity with epoxy groups, the modified supramolecular host-guest photoinitiator can induce polymerization while the supramolecular host compound participates in the epoxy curing reaction, effectively preventing adhesion failure caused by the migration of the supramolecular host compound.

[0015] Preferably, the supramolecular host-guest photoinitiator has the structure shown in Formula III:

[0016] R3 + The cationic portion of the cationic photoinitiator is selected from at least one of iodonium ion, thionium ion, ferrocene ion, quaternary ammonium ion, diazo ion, phosphonium ion, bromium ion, and chloride ion; R4 is a substituent of the cationic moiety in a cationic photoinitiator, selected from at least one of the following: hydrogen atom, substituted or unsubstituted alkyl group, substituted or unsubstituted heterochain alkyl group, substituted or unsubstituted aromatic ring group, substituted or unsubstituted alkoxy group, substituted or unsubstituted alkylthio group, substituted or unsubstituted cycloalkyl group, halogen atom, hydroxyl group, carbonyl group, carboxyl group, ester group, acyl group, amino group, mercapto group, and carboxyl salt. X - This refers to anion or anionic group that acts as a counterion to a cationic photoinitiator.

[0017] After combining with supramolecular host compounds, the affinity of cationic photoinitiators for materials such as resins is significantly enhanced, making them more soluble in various adhesive formulations used subsequently, thus solving problems such as poor solubility and high processing difficulty of some cationic photoinitiators.

[0018] Preferred, X - Selected from BF4 - PF6 - SbF6 - B(Ar)4 - At least one of the following: halogens and halide-like ions, p-toluenesulfonate (-OTs) and its derivatives, trifluoromethanesulfonate (-OTf) and its derivatives, and methanesulfonate (-OMs) and its derivatives.

[0019] The reaction equation for introducing highly reactive functional groups onto the macrocycle of the supramolecular host compound and forming a highly reactive supramolecular host-guest photoinitiator can be found in the following equation:

[0020] Among them, halogenated reagents include all halogenated reagents, including but not limited to hydrochloric acid, hydrobromic acid, p-toluenesulfonyl chloride, hydroiodic acid, phosphorus pentachloride, phosphorus trichloride, phosphorus tribromide, thionyl chloride, oxalyl chloride, etc.

[0021] Taking [8]-CPP∝I as an example, the following reaction equation demonstrates the delayed curing mechanism of supramolecular host-guest photoinitiators:

[0022] When [8]-CPP∝I is exposed to UV light, the guest photoinitiator molecule undergoes photolysis to generate HPF6, an active species that induces the polymerization of epoxy cationic compounds. However, initially, this active species is bound by the supramolecular macrocycle and cannot efficiently induce polymerization, resulting in a delayed curing window in the early stages of the reaction. Under chemical reaction equilibrium, a small amount of active species breaks free from its binding and induces slow polymerization. When polymerization reaches a certain level and / or the system temperature rises, the reaction equilibrium is broken, and the active species are rapidly released, exhibiting the typical polymerization rate of UV photocuring.

[0023] Secondly, the present invention also provides a UV epoxy adhesive with adjustable curing rate, comprising, by weight, the following components: 1-10 parts epoxy resin; 0.1-0.5 parts of supramolecular host-guest photoinitiator; 0.01-5 parts of silane coupling agent; 0-0.3 parts photosensitizer; 0-10 parts of reactive diluent; The supramolecular host-guest photoinitiator is the aforementioned supramolecular host-guest photoinitiator.

[0024] Specifically, the epoxy resin is selected from any epoxy resin, including but not limited to at least one of bisphenol A glycidyl ether epoxy resin, bisphenol F glycidyl ether epoxy resin, a mixture of bisphenol A and bisphenol F glycidyl ether epoxy resins, rubber-toughened glycidyl ether epoxy resin, aliphatic epoxy resin, and alicyclic epoxy resin. This invention employs a supramolecular host-guest photoinitiator with adjustable curing rate, thereby significantly reducing the limitations on the specific types and properties of epoxy resins, effectively overcoming the technical bottlenecks of traditional material selection limitations and difficulty in controlling the curing rate.

[0025] The silane coupling agent is selected from any silane coupling agent, including but not limited to 3-glycidoxypropyltrimethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, (3-epoxypropylpropoxy)trimethoxysilane, (3-epoxypropylpropoxy)triethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, etc.

[0026] The photosensitizer is selected from any photosensitizer, including but not limited to 2-isopropylthioxanthraquinone, camphorquinone, anthraquinone and its derivatives, methylene blue, porphyrin and its derivatives, etc.

[0027] The reactive diluent is selected from any reactive diluent, including but not limited to benzyl glycidyl ether (and its derivatives), alkyl glycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, allyl glycidyl ether, trifunctional glycidyl ether, tetrafunctional glycidyl ether, etc.

[0028] The UV epoxy adhesive with adjustable curing rate provided by this invention, after UV light irradiation initiation, does not cure immediately like traditional UV-cured adhesives due to the inclusion and slow-release effect of the supramolecular host compound on the guest photoinitiator. Instead, it provides a delayed curing function, forming a delayed curing window before the curing rate rapidly increases. During this window, the curing rate of the adhesive is very low (e.g., below 15%), and the adhesive exhibits excellent flow and coating properties, meeting flexible application requirements. UV light irradiation initiation can also be performed after application, allowing for a longer delayed curing time for bonding low UV transmittance components. After the window period, the adhesive can continue to initiate polymerization reactions independently of light irradiation, automatically completing subsequent curing, thus solving the problem that low UV transmittance components cannot be cured with UV adhesives.

[0029] Preferably, the adhesive thickness is 0.2-1 mm, and the wavelength is 200-500 nm with a curing energy of 200-20000 mJ / cm². 2After UV irradiation, the UV epoxy adhesive undergoes delayed curing, with a delayed curing window of 5 to 30 minutes and a degree of curing below 10% within the window. There are no particular limitations on the adhesive thickness; it depends on the bonding requirements. The UV irradiation time can be determined based on the adhesive thickness. For example, with an adhesive thickness of 0.2-1 mm, UV irradiation for 2-20 seconds is sufficient. After the window period, subsequent curing can proceed slowly at room temperature in the absence of light. For instance, after UV irradiation at room temperature, the adhesive reaches sufficient initial strength in about 15-35 minutes and is fully cured in about 1 hour. Alternatively, it can be cured rapidly under heating conditions. For example, heating the adhesive to 50-70°C can achieve near-complete curing within 1 minute. Heating can also be used within the window period. Once all curing preparations are complete, the window period can be broken by increasing the temperature to improve work efficiency.

[0030] Based on the use of supramolecular host-guest photoinitiators with adjustable curing rates, this invention can effectively control the curing rate of UV epoxy adhesives through various means such as initiator component design, application condition control, light source control, and temperature control, which has great advantages in use and promotion value.

[0031] Thirdly, the present invention also provides a method for preparing the aforementioned UV epoxy adhesive with adjustable curing rate, comprising the following steps: S1. After dissolving the guest photoinitiator, a supramolecular host compound is added to the solution, and crystals are precipitated by the reaction. S2. Remove the solvent, clean the crystal and vacuum dry it to obtain the supramolecular host-guest photoinitiator; S3. Mix the supramolecular host-guest photoinitiator with epoxy resin, silane coupling agent, and optionally photosensitizer and reactive diluent to obtain the UV epoxy adhesive.

[0032] Further, in step S1, the guest photoinitiator is dissolved in a solvent, which includes, but is not limited to, at least one selected from methanol, ethanol, acetone, chloroform, water, diethyl ether, toluene, benzene, 1,4-dioxane, N,N-dimethylacetamide, tetrahydrofuran, acetonitrile, dichloromethane, ethyl acetate, petroleum ether, n-hexane, isopropanol, and tert-butanol. A low-boiling-point solvent is preferred for easier subsequent removal.

[0033] Furthermore, in step S1, the reaction is carried out at a temperature of -20 to 200°C and a rotation speed of 10 to 2000 rpm, and the reaction atmosphere is selected from at least one of helium, nitrogen, oxygen, and air.

[0034] Furthermore, in step S2, after removing part of the solvent, the mixture is cooled to room temperature, an inert solvent is added to the remaining liquid, the mixture is filtered, and the crystal filter cake is washed and filtered multiple times with the aforementioned solvent before being placed in a vacuum oven to dry.

[0035] Furthermore, removing a portion of the solvent includes removing 30-70% of the total solvent.

[0036] Furthermore, the inert solvent includes, but is not limited to, at least one of n-hexane, petroleum ether, diethyl ether, and n-heptane. It is used to promote the further precipitation of the reaction product generated in step S1.

[0037] Fourthly, based on the aforementioned supramolecular host-guest photoinitiator and UV epoxy adhesive with adjustable curing rate, this invention provides an application of using a UV epoxy adhesive with adjustable curing rate for bonding low UV transmittance components.

[0038] Preferably, the application steps include the following: The UV epoxy adhesive is irradiated with UV light and then initiated, allowing it to enter a delayed curing window. During the window period, the UV epoxy adhesive is bonded to the low UV transmission component; The UV epoxy adhesive may be selected using any of the following post-curing methods: (1) Room temperature, light-free, slow curing; (2) Rapid curing upon heating; (3) Control the heating temperature and adjust the curing rate.

[0039] Furthermore, the UV epoxy adhesive is applied to the substrate before, after, or simultaneously with the UV light irradiation of the UV epoxy adhesive to enter the delayed curing window.

[0040] Low UV transmittance components typically refer to components with a UV transmittance of less than 20%, such as non-transparent substrates (e.g., metals, ceramics, carbon fibers, black / dark plastics), substrates containing UV absorbers (e.g., certain weather-resistant coatings, sun-protective packaging materials, optical protective films), and multilayer composite substrates (e.g., glass with a UV-shielding layer, UV-resistant films). In specific applications, the UV transmittance of some medical packaging, electronic display protective films, and high-end optical films must be controlled below 5%, while the transmittance of some aerospace optical windows must be controlled below 1%.

[0041] The UV epoxy adhesive with adjustable curing rate of the present invention actually demonstrates at least two adjustment methods in application. The first adjustment is achieved by selecting material components such as supramolecular host-guest photoinitiators to obtain an adjustable window period, providing a basic setting for delayed curing. The second adjustment is achieved by adjusting the curing temperature of the post-curing process, thereby controlling the post-curing start point and curing rate, realizing flexible setting of the curing rate throughout the process.

[0042] The present invention has at least the following beneficial effects: (1) The supramolecular host-guest photoinitiator of the present invention, through the inclusion and slow-release effect of the supramolecular host compound on the guest photoinitiator, does not immediately induce rapid polymerization of its initiating target, thus forming a delayed curing window. During the window period, a small amount of active species induces slow polymerization. When the polymerization reaches a certain level and / or the system temperature rises, the reaction equilibrium is broken and the window period ends, and the active species are rapidly released to accelerate polymerization, thereby providing a photocuring polymerization technology with adjustable curing rate. Furthermore, based on the differences in the macrocyclic structure of the supramolecular host compound, the delayed window period can be artificially controlled, thereby providing different operating windows according to specific process requirements, greatly improving the convenience and user-friendliness of construction.

[0043] (2) The UV epoxy adhesive of the present invention utilizes the controllability of the curing rate of the supramolecular host-guest photoinitiator, and can be applied to the substrate surface before, after or simultaneously with UV light excitation. By utilizing the flow state maintained by the adhesive during the delayed curing window, the low UV transmission component is bonded to the adhesive, and can be cured at room temperature in the absence of light, thus solving the problem that low UV transmission components cannot be cured with UV adhesive.

[0044] (3) The present invention improves the affinity between cationic photoinitiators and materials such as resins by using the macrocyclic structure of supramolecular main compounds, making them easier to dissolve in adhesive formulations and solving the problem of high process difficulty caused by the poor solubility of cationic photoinitiators.

[0045] (4) The present invention also introduces reactive functional groups on the macrocycle of the supramolecular host compound, which not only further extends the delayed curing window period, but also utilizes the highly active reactive functional groups and epoxy groups to enable the modified supramolecular host-guest photoinitiator to play an induction polymerization role while enabling the supramolecular host compound to participate in the epoxy curing reaction, effectively avoiding adhesion failure caused by the migration of the supramolecular host compound. Detailed Implementation

[0046] To better understand the above technical solutions, a detailed description of the solutions will be provided below in conjunction with the specification and specific implementation methods. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0048] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0049] A supramolecular host-guest photoinitiator with adjustable curing rate comprises a supramolecular host compound and a guest photoinitiator encapsulated therein, wherein the molar ratio of the supramolecular host compound to the guest photoinitiator is (0.8-1.5):1, and the mass percentage of carbon and hydrogen is (40-75):(3-8). The supramolecular host-guest photoinitiator has the structure shown in Formula III.

[0050] (1) The supramolecular host compound has a macrocyclic structure with 2-30 repeating units, preferably as shown in Formula I:

[0051] R1 is an independent repeating unit selected from at least one main structure of cyclophenylene, crown ether, calixarene, columnar aromatics, cyclodextrin, and cucurbituril, where n is a positive integer selected from 2 to 30; R2 and Ra independently include at least one of the following: hydrogen atom, substituted or unsubstituted alkyl group, substituted or unsubstituted heterochain alkyl group, substituted or unsubstituted aromatic ring group, substituted or unsubstituted alkoxy group, substituted or unsubstituted alkylthio group, substituted or unsubstituted cycloalkyl group, halogen atom, hydroxyl group, carbonyl group, carboxyl group, ester group, acyl group, amino group, mercapto group, and carboxyl salt, where * is the bonding site between Ra and the macrocyclic structure. Preferably, Ra includes the structure shown in Formula II:

[0052] Rb includes at least one of hydrogen atom, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C1-C10 heterochain alkyl, and substituted or unsubstituted C1-C6 alkoxy. R5 is independently selected from one of the following groups: .

[0053] (2) Guest photoinitiators include cationic photoinitiators, which are represented in the structural formula III of supramolecular host-guest photoinitiators as follows: R3 + The cationic portion of the cationic photoinitiator is selected from at least one of iodonium ion, thionium ion, ferrocene ion, quaternary ammonium ion, diazo ion, phosphonium ion, bromium ion, and chloride ion; R4 is a substituent of the cationic moiety in a cationic photoinitiator, selected from at least one of the following: hydrogen atom, substituted or unsubstituted alkyl group, substituted or unsubstituted heterochain alkyl group, substituted or unsubstituted aromatic ring group, substituted or unsubstituted alkoxy group, substituted or unsubstituted alkylthio group, substituted or unsubstituted cycloalkyl group, halogen atom, hydroxyl group, carbonyl group, carboxyl group, ester group, acyl group, amino group, mercapto group, and carboxyl salt. X - The anion or anionic group representing the counterion of a cationic photoinitiator is preferably X. - Selected from BF4 - PF6-, SbF6 - B(Ar)4 - At least one of the following: halogens and halide-like ions, p-toluenesulfonate (-OTs) and its derivatives, trifluoromethanesulfonate (-OTf) and its derivatives, and methanesulfonate (-OMs) and its derivatives.

[0054] Specifically, the supramolecular host-guest photoinitiators with adjustable curing rates of the present invention include, but are not limited to, the following types: [7]-CPP∝I, [8]-CPP∝I, [9]-CPP∝I, [9]-CPP∝OI, etc., based on cyclophenylene rings, for example: (1.1) [9]-CPP∝I structure is as follows:

[0055] (1.2) [9]-CPP∝OI structure is as follows:

[0056] (2) Crown ethers such as 18-C-6∝Fe, 18-C-6∝S, 24-C-8∝S, etc., for example: (2.1) The structural formula of 18-C-6∝Fe is as follows:

[0057] (2.2) The structural formula of 24-C-8∝S is as follows:

[0058] (3) Based on calixarene, CA[6]∝I, etc., the structural formula of CA[6]∝I is as follows:

[0059] (4) Supramolecular host-guest photoinitiators with highly reactive functional groups on the supramolecular macrocycle, for example: (4.1) The side-chain epoxy-substituted 18-C-6∝Fe (also known as epoxy-18-C-6∝Fe) has the following structural formula:

[0060] (4.2) The side chain has unsaturated double bonds of 18-C-6∝Fe (also called ene-18-C-6∝Fe), with the following structural formula:

[0061] (4.3) The side chain has an oxocyclic butane 18-C-6∝S (also called ox-18-C-6∝S), with the following structural formula:

[0062] A UV epoxy adhesive with adjustable curing rate, comprising, by weight, the following components: (1) 1-10 parts of epoxy resin, selected from any epoxy resin, such as at least one of bisphenol A type glycidyl ether type epoxy resin, bisphenol F type glycidyl ether type epoxy resin, a mixture of bisphenol A type and bisphenol F type glycidyl ether type epoxy resin, rubber toughening type glycidyl ether epoxy, aliphatic epoxy resin, and alicyclic epoxy resin. (2) 0.1-0.5 parts of the aforementioned supramolecular host-guest photoinitiator; (3) 0.01-5 parts of silane coupling agent, any silane coupling agent, such as 3-glycidoxypropyltrimethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, (3-epoxypropylpropoxy)trimethoxysilane, (3-epoxypropylpropoxy)triethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, etc. (4) 0-0.3 parts of photosensitizer, any photosensitizer, such as 2-isopropylthioxanthraquinone, camphorquinone, anthraquinone and its derivatives, methylene blue, porphyrin and its derivatives, etc.; (5) 0-10 parts of reactive diluent, any reactive diluent, such as benzyl glycidyl ether (and its derivatives), alkyl glycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, allyl glycidyl ether, trifunctional glycidyl ether, tetrafunctional glycidyl ether, etc.

[0063] The adhesive thickness and UV light source can be selected according to actual needs. Generally, an adhesive thickness of 0.2-1mm is sufficient for bonding requirements. The UV light wavelength should be 200-500nm, and the curing energy should be 200-20000mJ / cm². 2 It can meet the requirements for initiation and curing, and the degree of curing is easy to control.

[0064] Using the aforementioned UV epoxy adhesive formulation, with an application thickness of 0.2-1 mm, a wavelength of 200-500 nm and a curing energy of 200-20000 mJ / cm² are applied. 2 After UV light irradiation (approximately 2-20 seconds), the UV epoxy adhesive undergoes delayed curing. The delayed curing window is between 5 and 30 minutes, and the degree of curing within the window is below 10%. After the window period, subsequent curing can proceed slowly at room temperature in the absence of light. For example, after UV light irradiation at room temperature, the adhesive can achieve sufficient initial strength in about 15-35 minutes and be fully cured in about 1 hour. Alternatively, it can be cured rapidly under heating conditions. For example, heating the adhesive to 50-70°C can achieve near-complete curing within 1 minute. Heating can also be used within the window period. Once all curing preparations are complete, the window period can be broken by increasing the temperature to improve work efficiency.

[0065] A method for preparing the aforementioned UV epoxy adhesive with adjustable curing rate includes the following steps: S1. Dissolve the guest photoinitiator in a solvent, add the supramolecular host compound to the solution, and react at a temperature of -20~200℃ and a rotation speed of 10-2000rpm to precipitate crystals; S2. Remove some of the solvent by rotary evaporation and cool to room temperature. Add an inert solvent to the residual liquid, filter, and then wash the crystal filter cake several times (at least 3 times) with a small amount of the aforementioned solvent, filter, and then dry in a vacuum oven to obtain the supramolecular host-guest photoinitiator. S3. Mix the supramolecular host-guest photoinitiator with epoxy resin, silane coupling agent, and optionally photosensitizer and reactive diluent to obtain the UV epoxy adhesive.

[0066] An application of the aforementioned UV epoxy adhesive with adjustable curing rate for bonding low UV transmittance components includes the following application steps: Before, after, or simultaneously with the application of the UV epoxy adhesive to the substrate, the UV epoxy adhesive is irradiated with UV light and the UV epoxy adhesive is initiated, allowing the UV epoxy adhesive to enter a delayed curing window. During the window period, the UV epoxy adhesive is bonded to the low UV transmission component; The UV epoxy adhesive may be selected using any of the following post-curing methods: (1) Slow curing at room temperature without light. After UV light exposure, the adhesive can achieve sufficient initial strength in about 15-35 minutes and is fully cured in about 1 hour. (2) Rapid curing by heating: If the adhesive is heated to 50-70℃, it can be basically completely cured within 1 minute; (3) Control the heating temperature and adjust the curing rate.

[0067] Example 1 The supramolecular host-guest photoinitiator and UV epoxy adhesive sample with adjustable curing rate of Example 1 were prepared by the following steps: (1) Synthesis of supramolecular host-guest photoinitiators 2 mmol of diphenyliodonium hexafluorophosphate was dissolved in methanol, and then 2 mmol of 8-cyclop-phenylene([8]-CPP) was added to the solution. The [8]-CPP dissolved and crystals precipitated. After the reaction was complete, half of the methanol was removed by rotary evaporation, the mixture was cooled to room temperature, n-hexane was added, and the mixture was filtered. The filter cake was washed three times with a small amount of methanol and then dried in a vacuum oven to obtain colorless crystals 8-[CPP]∝I.

[0068] The reaction equation for the synthesis of 8-[CPP]∝I is as follows:

[0069] Elemental analysis: Theoretical value: C 61 H 46 F6IP: %C(69.72), %H(4.41); Actual values: %C (69.65), %H (4.55).

[0070] (2) Preparation of UV epoxy adhesive 0.2 parts by mass of supramolecular host-guest photoinitiator 8-[CPP]∝I, 0.1 parts by mass of photosensitizer ITX, 2.5 parts by mass of bisphenol A epoxy resin, 2.5 parts by mass of 2021p epoxy resin, and 0.05 parts by mass of silane coupling agent are thoroughly stirred and mixed evenly to obtain the UV epoxy adhesive.

[0071] Example 2 The supramolecular host-guest photoinitiator and UV epoxy adhesive sample with adjustable curing rate in Example 2 were prepared by the following steps: (1) Synthesis of supramolecular host-guest photoinitiators 2 mmol of diphenyliodonium hexafluorophosphate was dissolved in methanol, followed by the addition of 2 mmol of 7-cyclop-phenylene([7]-CPP). The [7]-CPP dissolved and crystals precipitated. After the reaction was complete, half of the methanol was removed by rotary evaporation, the mixture was cooled to room temperature, hexane was added, and the mixture was filtered. The filter cake was washed three times with a small amount of methanol. Finally, the mixture was dried in a vacuum oven to obtain colorless crystals 7-[CPP]∝I.

[0072] The reaction equation for the synthesis of 7-[CPP]∝I is as follows:

[0073] Elemental analysis: Theoretical value: C 54 H 38 F6IP: %C(67.65), %H(4.00); Actual values: %C (67.56), %H (4.12). (2) Preparation of UV epoxy adhesive The difference from Example 1 is that the supramolecular host-guest photoinitiator used is 0.19 parts by weight of 7-[CPP]∝I.

[0074] Example 3 The supramolecular host-guest photoinitiator and UV epoxy adhesive sample with adjustable curing rate in Example 3 were prepared by the following steps: (1) Synthesis of supramolecular host-guest photoinitiators 2 mmol of diphenyliodonium hexafluorophosphate was dissolved in methanol, followed by the addition of 2 mmol of 9-cyclop-phenylene([9]-CPP). The [9]-CPP dissolved and crystals precipitated. After the reaction was complete, half of the methanol was removed by rotary evaporation, the mixture was cooled to room temperature, hexane was added, and the mixture was filtered. The filter cake was washed three times with a small amount of methanol. Finally, the mixture was dried in a vacuum oven to obtain colorless crystals 9-[CPP]∝I.

[0075] The reaction equation for the synthesis of [9]-CPP∝I is as follows:

[0076] Elemental analysis: Theoretical value: C 67 H 50 F6IP: %C(71.40), %H(4.47); Actual values: %C (71.46), %H (4.39).

[0077] (2) Preparation of UV epoxy adhesive The difference from Example 1 is that the supramolecular host-guest photoinitiator used is 0.22 parts by mass of 9-[CPP]∝I.

[0078] Example 4 The supramolecular host-guest photoinitiator and UV epoxy adhesive sample with adjustable curing rate in Example 4 were prepared by the following steps: (1) Synthesis of supramolecular host-guest photoinitiators Two mmol of methoxy-substituted diphenyliodide antimonate was dissolved in methanol, followed by the addition of two mmol of 9-cyclop-phenylene([9]-CPP). The [9]-CPP dissolved and crystals precipitated. After the reaction was complete, half of the methanol was removed by rotary evaporation, the mixture was cooled to room temperature, hexane was added, and the mixture was filtered. The filter cake was washed three times with a small amount of methanol. Finally, the mixture was dried in a vacuum oven to obtain colorless crystals 9-[CPP]∝OI.

[0079] The reaction equation for the synthesis of [9]-CPP∝OI is as follows:

[0080] Elemental analysis: Theoretical value: C 66 H 46 F6IOSb: %C(65.33), %H(3.93); Actual values: %C (65.01), %H (4.02).

[0081] (2) Preparation of UV epoxy adhesive The difference from Example 1 is that the supramolecular host-guest photoinitiator used is 0.24 parts by mass of 9-[CPP]∝OI.

[0082] Example 5 The supramolecular host-guest photoinitiator and UV epoxy adhesive sample with adjustable curing rate in Example 5 were prepared by the following steps: (1) Synthesis of supramolecular host-guest photoinitiators 2 mmol of di-p-tolylphenyliodonium salt was dissolved in methanol, and then 2 mmol of calix[6]arene (CA[6]) was added to the solution. The CA[6] dissolved and crystals precipitated. After the reaction was complete, half of the methanol was removed by rotary evaporation, the mixture was cooled to room temperature, n-hexane was added, and the mixture was filtered. The filter cake was washed three times with a small amount of methanol. Finally, the mixture was dried in a vacuum oven to obtain colorless crystals CA[6]∝I.

[0083] The reaction equation for the synthesis of CA[6]∝I is as follows:

[0084] Elemental analysis: Theoretical value: C 80 H 50 BF 20 IO6: %C (59.13), %H (3.10); Actual values: %C (58.88), %H (3.11).

[0085] (2) Preparation of adhesive composition The difference from Example 1 is that the supramolecular host-guest photoinitiator used is 0.31 parts by mass of CA[6]∝I.

[0086] Example 6 The supramolecular host-guest photoinitiator and UV epoxy adhesive sample with adjustable curing rate in Example 6 were prepared by the following steps: (1) Synthesis of supramolecular host-guest photoinitiators 2 mmol of ferrocene hexafluorophosphate was dissolved in methanol, followed by the addition of 2 mmol of 18-crown-6 (18-C-6). The 18-C-6 dissolved, precipitating crystals. After the reaction was complete, half of the methanol was removed by rotary evaporation. The solution was cooled to room temperature, and hexane was added. The mixture was filtered, and the filter cake was washed three times with a small amount of methanol. Finally, the solution was dried in a vacuum oven to obtain colorless crystals of 18-C-6∝Fe.

[0087] The reaction equation for the synthesis of 18-C-6∝Fe is as follows:

[0088] Elemental analysis: Theoretical value: C 22 H 34 F6FeO6P: %C (44.39), %H (5.76); Actual values: %C (44.44), %H (5.81).

[0089] (2) Preparation of UV epoxy adhesive 0.12 parts by weight of supramolecular host-guest photoinitiator 18-C-6∝Fe, 2.5 parts by weight of bisphenol F epoxy resin, 2.5 parts by weight of 2021p epoxy resin, and 0.05 parts by weight of silane coupling agent are thoroughly stirred and mixed evenly to obtain the UV epoxy adhesive.

[0090] Example 7 The supramolecular host-guest photoinitiator and UV epoxy adhesive sample with adjustable curing rate in Example 7 were prepared by the following steps: (1) Synthesis of supramolecular host-guest photoinitiators Two mmol of the antimonate salt of thioonium was dissolved in methanol, followed by the addition of two mmol of 18-crown-6 (18-C-6). The 18-C-6 dissolved and crystals precipitated. After the reaction was complete, half of the methanol was removed by rotary evaporation. The mixture was cooled to room temperature, and n-hexane was added. The mixture was filtered, and the filter cake was washed three times with a small amount of methanol. Finally, it was dried in a vacuum oven to obtain colorless crystals of 18-C-6∝S.

[0091] The reaction equation for the synthesis of 18-C-6∝S is as follows:

[0092] Elemental analysis: Theoretical value: C 31 H 41 F6O6S2Sb: %C(74.8), %H(5.11).

[0093] Actual values: %C (74.23), %H (4.98).

[0094] (2) Preparation of UV epoxy adhesive The difference from Example 6 is that the supramolecular host-guest photoinitiator used is 0.16 parts by weight of 18-C-6∝S.

[0095] Example 8 The supramolecular host-guest photoinitiator and UV epoxy adhesive sample with adjustable curing rate in Example 8 were prepared by the following steps: (1) Synthesis of supramolecular host-guest photoinitiators Two mmol of the antimonate salt of thioonium was dissolved in methanol, followed by the addition of two mmol of 24-crown-8 (24-C-8). The 24-C-8 dissolved, precipitating crystals. After the reaction was complete, half of the methanol was removed by rotary evaporation. The solution was cooled to room temperature, and hexane was added. The mixture was filtered, and the filter cake was washed three times with a small amount of methanol. Finally, the solution was dried in a vacuum oven to obtain colorless crystals of 24-C-8∝S.

[0096] The reaction equation for the synthesis of 24-C-8∝S is as follows:

[0097] Elemental analysis: Theoretical value: C 35 H 49 F6O8S2Sb: %C(46.83), %H(5.50); Actual values: %C (46.54), %H (5.23).

[0098] (2) Preparation of UV epoxy adhesive 0.17 parts by weight of 24-C-8∝S, 5 parts by weight of 2021p epoxy resin, and 0.05 parts by weight of silane coupling agent are thoroughly stirred and mixed evenly to obtain the UV epoxy adhesive.

[0099] Example 9 The supramolecular host-guest photoinitiator and UV epoxy adhesive sample with adjustable curing rate of Example 9 were prepared by the following steps: (1) Synthesis of supramolecular host-guest photoinitiator epoxy-18-C-6∝Fe, the reaction equation is as follows:

[0100] S1. Dissolve 2 mmol of hydroxymethyl-substituted 18-crown-6 (18-C-6) in dichloromethane, then add 2.5 mmol of p-toluenesulfonyl chloride TsCl and a catalytic amount of DMAP to the solution. After the reaction is complete as monitored by TLC, pour the reaction solution into water, extract with dichloromethane, evaporate the solvent, and use the crude product directly for the next step of the reaction.

[0101] S2. Dissolve 2 mmol of glycidol in tetrahydrofuran, then add NaH at 0°C, and allow to return to room temperature. React for half an hour. Add the crude product obtained in step S1 to this reaction solution. After the reaction is complete, quench the reaction with water, extract with dichloromethane, dry, and evaporate to dryness. Further column chromatography of the crude product yields 18-crown-6 with epoxy-substituted side chains (a supramolecular host compound with reactive functional groups).

[0102] S3. The steps for synthesizing the supramolecular host-guest photoinitiator epoxy-18-C-6∝Fe using 18-crown-6 with side-chain epoxy substitution and ferrocene hexafluorophosphate are the same as in Example 6.

[0103] Elemental analysis: Theoretical value: C 26 H 40 F6FeO8P: %C (45.83), %H (5.92); Actual values: %C (45.66), %H (5.79).

[0104] (2) Preparation of UV epoxy adhesive The difference from Example 6 is that the supramolecular host-guest photoinitiator used is 0.13 parts by mass of epoxy-18-C-6∝Fe.

[0105] Example 10 The supramolecular host-guest photoinitiator and UV epoxy adhesive sample with adjustable curing rate of Example 10 were prepared by the following steps: (1) Synthesis of supramolecular host-guest photoinitiator ene-18-C-6∝Fe, the reaction equation is as follows:

[0106] The specific synthesis method of ene-18-C-6∝Fe is similar to that in Example 9, except that in step S2, 2 mmol of hydroxypropyl vinyl ether is dissolved in tetrahydrofuran.

[0107] Elemental analysis: Theoretical value: C 28 H 44 F6FeO8P: %C (47.40), %H (6.85); Actual values: %C (47.29), %H (6.68).

[0108] (2) Preparation of UV epoxy adhesive The difference from Example 6 is that the supramolecular host-guest photoinitiator used is 0.14 parts by mass of ene-18-C-6∝Fe.

[0109] Example 11 The supramolecular host-guest photoinitiator and UV epoxy adhesive sample with adjustable curing rate of Example 11 were prepared by the following steps: (1) Synthesize the supramolecular host-guest photoinitiator ox-18-C-6∝S. The reaction equation is as follows:

[0110] The specific synthesis method of ox-18-C-6∝S is similar to that of Example 9, except that in step S2, 2 mmol of 3-methyl-3-hydroxymethyloxetane is dissolved in tetrahydrofuran.

[0111] Elemental analysis: Theoretical value: C 37 H 51 F6O8S2Sb: %C(48.11), %H(5.57); Actual values: %C (48.01), %H (5.55).

[0112] (2) Preparation of UV epoxy adhesive The difference from Example 6 is that the supramolecular host-guest photoinitiator used is 0.18 parts by mass of ox-18-C-6∝S.

[0113] Comparative Example 1 This comparative example provides an adhesive composition that, unlike Example 1, does not use a supramolecular host-guest photoinitiator, but instead directly adds 0.1 parts by weight of diphenyliodonium hexafluorophosphate.

[0114] Comparative Example 2 This comparative example provides an adhesive composition that, unlike Example 6, does not use a supramolecular host-guest photoinitiator but directly adds 0.06 parts by weight of ferrocene hexafluorophosphate.

[0115] Comparative Example 3 This comparative example provides an adhesive composition that, unlike Example 8, does not use a supramolecular host-guest photoinitiator, but instead directly adds 0.08 parts by mass of a thioonium salt antimonate.

[0116] Comparative Example 4 This comparative example provides an adhesive composition that, unlike Example 6, does not use a supramolecular host-guest photoinitiator. Instead, 0.07 parts by weight of ferrocene hexafluorophosphate and 0.05 parts by weight of 18-crown-6 ether are mixed evenly with other materials during the preparation of the adhesive composition.

[0117] Tests and Results 1. The acid-producing performance of the supramolecular host-guest photoinitiators used in Examples 1 to 11 and the initiators used in Comparative Examples 1 to 3 was tested.

[0118] The concentration was set at 1.5 × 10⁻⁶. -5 A dilute acetonitrile solution of mol / L photoinitiator was prepared, with the photosensitizer ITX added at a molar ratio of 0.5:1. A few drops of Rhodamine B solution were added as a pH indicator. The mixture was thoroughly mixed, and then the prepared solution was placed under 365 nm ultraviolet light (light intensity 300 mW / cm²). 2 The solution was irradiated under a light source, and the time for color change (in minutes) was recorded. The test results are shown in Table 1.

[0119] Table 1

[0120] The solution color change time of Examples 1-11 was all above 5 minutes. Compared with Comparative Examples 1-3, which directly added the corresponding cationic photoinitiators, they showed a significant delay effect. The main reason is the inclusion and sustained-release effect of the supramolecular host compound on the guest photoinitiator. Furthermore, due to the different composition and ratio of the supramolecular host and guest photoinitiators in each example, a wide range of different delayed color change times were also observed. This provides a particularly advantageous delayed window period that can adapt to different curing requirements and has great practical application value.

[0121] 2. The adhesive samples obtained from each embodiment and comparative example were evaluated in the following aspects, and the test results are shown in Table 2: 2.1 Delay Window: A 0.5 mm thick adhesive layer was prepared using a coating machine and placed under 365 nm ultraviolet light (light intensity: 300 mW / cm²).2 Irradiate for 10 seconds. Gently pick at the adhesive layer with a toothpick every 1 minute. The time when the adhesive layer begins to string is defined as the delayed curing window (unit: min).

[0122] 2.2 Time required to reach 0.1 MPa strength: Samples were prepared using the chip shearing method, with glass substrates bonded together, the bonding area being 3 mm × 3 mm. The cured adhesive was tested every 2 minutes using a Dage chip pusher, and the time required for the strength value to first exceed 0.1 MPa (unit: min) and the actual strength value measured at that time (unit: MPa) were recorded.

[0123] 2.3 Bond strength after 5 min: The adhesive film was heated at 60℃ for 1 min, and the shear strength (unit: MPa) was tested after 5 min.

[0124] 2.4 Final strength: Record the shear strength (unit: MPa) after 24 h.

[0125] Table 2

[0126] As can be seen from the comparison, the adhesive samples of Examples 1-11 exhibit a delayed curing window period that basically corresponds to the delayed color change time in Table 1, indicating their effectiveness and reliability in adhesive applications. In contrast, Comparative Examples 1-3 do not have a window period; their adhesive samples were observed to cure rapidly after UV irradiation, essentially completing curing within 1 minute, and reaching a high bond strength value at 2 minutes.

[0127] Comparative Example 4 incorporated the same supramolecular host compound and guest photoinitiator as Example 6. The macrocyclic structure of the supramolecular host compound also exhibited a certain delay effect on the guest photoinitiator. However, since the two did not react in advance to form a stable supramolecular host-guest photoinitiator, the window of delayed curing was too short. In practical applications, there was not enough time to perform accurate bonding operations. It can be seen that the simple mixed slow-release effect is limited. Only by using the supramolecular host compound to encapsulate the guest photoinitiator to prepare a supramolecular host-guest photoinitiator can it have a practical delayed curing effect and application value.

[0128] The preferred embodiments of the present invention have been described above, which are intended to make the spirit of the present invention clearer and easier to understand, and are not intended to limit the present invention. All modifications, substitutions and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A supramolecular host-guest photoinitiator with adjustable cure rate, characterized in that, This includes supramolecular host compounds and guest photoinitiators encapsulated within them; Guest photoinitiators include cationic photoinitiators; The supramolecular host compound has the macrocyclic structure shown in Formula I: ； R1 is an independent repeating unit selected from at least one main structure of cyclophenylene, crown ether, calixarene, columnar aromatics, cyclodextrin, and cucurbituril, where n is a positive integer selected from 2 to 30; R2 and Ra independently include at least one of the following: hydrogen atom, substituted or unsubstituted alkyl group, substituted or unsubstituted heterochain alkyl group, substituted or unsubstituted aromatic ring group, substituted or unsubstituted cycloalkyl group, halogen atom, hydroxyl group, carboxyl group, amino group, mercapto group, and carboxyl salt. * is the bonding site between Ra and the macrocyclic structure.

2. The supramolecular host-guest photoinitiator of claim 1, wherein, Ra includes the structure shown in Equation II: ； Rb includes at least one of substituted or unsubstituted C1-C10 alkyl groups and substituted or unsubstituted C1-C10 heterochain alkyl groups; R5 is independently selected from one of the following groups: 。 3. The supramolecular host-guest photoinitiator of claim 1, wherein, Supramolecular host-guest photoinitiators have the structure shown in Formula III: ； R3 + R3 is selected from at least one of iodonium ion, sulfonium ion, arene iron ion, quaternary ammonium ion, diazonium ion, phosphonium ion, bromonium ion, and chloronium ion; R4 is a substituent of the cationic moiety in a cationic photoinitiator, selected from at least one of hydrogen atoms, substituted or unsubstituted alkyl groups, substituted or unsubstituted heterochain alkyl groups, substituted or unsubstituted aromatic ring groups, and substituted or unsubstituted cycloalkyl groups. X - represents an anion or anion group as a counterion of the cationic photoinitiator.

4. The supramolecular host-guest photoinitiator of claim 3, wherein, X - Selected from BF4 - PF6 - SbF6 - B(Ar)4 - At least one of the following: halogens and halide-like ions, p-toluenesulfonate, trifluoromethanesulfonate, and methanesulfonate.

5. The supramolecular host-guest photoinitiator according to any one of claims 1 to 4, wherein the host is a cyclodextrin. The supramolecular host-guest photoinitiator includes at least one of the following structures: (1) At least one of [7]-CPP∝I, [8]-CPP∝I, [9]-CPP∝I, and [9]-CPP∝OI based on cyclophenylene; (2) At least one of the crown ethers 18-C-6∝Fe, 18-C-6∝S, and 24-C-8∝S; (3) CA[6]∝I based on calixarene; (4) It has highly reactive functional groups on the macrocyclic structure of the supramolecular host compound.

6. The supramolecular host-guest photoinitiator of claim 5, wherein, The supramolecular host-guest photoinitiator has highly reactive functional groups on the macrocyclic structure of the supramolecular host compound, including at least one of the following structures: (1) 18-C-6∝Fe with side-chain epoxy substitution; (2) 18-C-6∝Fe with unsaturated double bonds in the side chain; (3) The side chain has 18-C-6∝S of oxobutane.

7. A method for preparing a supramolecular host-guest photoinitiator as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. After dissolving the guest photoinitiator, a supramolecular host compound is added to the solution, and crystals are precipitated by the reaction. S2. Remove the solvent, clean the crystal and vacuum dry it to obtain the supramolecular host-guest photoinitiator.

8. The production method according to claim 7, wherein In step S1, the guest photoinitiator is dissolved using a low-boiling-point solvent, wherein the low-boiling-point solvent includes at least one of methanol, diethyl ether, dichloromethane, ethyl acetate, petroleum ether, n-hexane, isopropanol, and tert-butanol. In step S2, some of the low-boiling-point solvent is removed, the mixture is cooled to room temperature, an inert solvent is added to the residual liquid, the mixture is filtered, and the crystal filter cake is washed and filtered multiple times with a small amount of the low-boiling-point solvent. The mixture is then placed in a vacuum oven to dry, thereby obtaining the supramolecular host-guest photoinitiator.

9. The production method according to claim 8, wherein The inert solvent includes at least one of n-hexane, petroleum ether, diethyl ether, and n-heptane.

10. A UV epoxy adhesive with adjustable curing rate, characterized in that, Includes the supramolecular host-guest photoinitiator as described in any one of claims 1-6.

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