UV thermal dual-curing adhesive and preparation method thereof

Abstract

The embodiment of the invention provides a UV (ultraviolet) thermal dual-curing adhesive and a preparation method thereof. The UV thermal dual-curing adhesive comprises the following components in percentage by mass: 30-55% of a photocuring prepolymer; 5%-25% of an active diluent monomer; 1%-10% of a photoinitiator; 1%-20% of a thermal initiator; 10%-40% of a filler; 0.5%-5% of a coupling agent; 1%-10% of a thixotropic agent; 1%-10% of pigment; 2%-8% of an auxiliary agent; wherein the photocuring prepolymer comprises epoxy resin. According to the UV thermal dual-curing adhesive and the preparation method thereof provided by the embodiment of the invention, the dual-curing adhesive with low shrinkage and low thermal expansion coefficient is obtained by optimizing the structure of the photocuring prepolymer and matching the components, and the prepared adhesive can be rapidly cured under the irradiation of LED 365nm ultraviolet light, or can be thermally cured under the low-temperature condition of 80 DEG C, so that the UV thermal dual-curing adhesive can be widely applied to the field of ultraviolet curing. The product can resist high and low temperature cycle impact of-50 DEG C to 140 DEG C, and has a good application prospect.

Description

Technical Field

[0001] The present application belongs to the technical field of adhesives, and in particular relates to a UV-heat dual-curing adhesive and a preparation method thereof. Background Art

[0002] Currently, products such as optical image stabilization, ultra-high pixel count, and large apertures require active alignment technology for optimal manufacturing. Future products may also require this technology, pushing the packaging and manufacturing of high-end products to the threshold of AA (Active Alignment). During the camera module packaging process, zoom cameras utilize active alignment technology to secure the lens to the base, preventing malfunctions caused by focal length fluctuations and bonding the infrared component to the voice coil motor. To achieve this process requirement, dual-cure (UV + thermosetting) adhesives are required. These adhesives are widely used in automotive camera modules, mobile phone camera modules, security camera modules, and micro camera modules.

[0003] However, current dual-cure adhesives either use acrylate functional groups as curing agents for epoxy resins. Although they have excellent heat and water resistance, they have high curing temperatures and a limited range of applications. Alternatively, they use resins in combination with hydrolysis-resistant polythiol compounds to achieve rapid UV light fixation and low-temperature rapid curing. The cured product has good heat resistance but cannot withstand high temperature and high humidity for a long time.

[0004] Based on this, the current dual-cure adhesives cannot fully meet the current market performance requirements for adhesives, and there is an urgent need to develop a new dual-cure adhesive. Summary of the Invention

[0005] In view of this, the embodiments of the present application provide a UV thermal dual-curing adhesive and a preparation method thereof to solve the technical problem that the existing dual-curing adhesive cannot fully meet the current market performance requirements for adhesives.

[0006] In a first aspect, an embodiment of the present application provides a UV thermal dual curing adhesive comprising the following components in percentage by mass:

[0007] Light-curing prepolymer 30% to 55%;

[0008] Active dilution monomer 5% to 25%;

[0009] Photoinitiator 1% to 10%;

[0010] Thermal initiator 1% to 20%;

[0011] Filler 10% to 40%;

[0012] Coupling agent 0.5% to 5%;

[0013] Thixotropic agent 1% to 10%;

[0014] Pigment 1% to 10%;

[0015] Additives 2% to 8%;

[0016] Wherein, the photocurable prepolymer includes epoxy resin.

[0017] In some embodiments, the photocurable prepolymer further comprises a polyurethane acrylate resin, and the mass ratio of the epoxy resin to the polyurethane acrylate resin is 1 to 5:1.

[0018] In some embodiments, the epoxy resin includes an aromatic glycidyl ether having at least two epoxy groups.

[0019] In some embodiments, the epoxy resin includes a cycloaliphatic epoxy resin having at least two epoxy groups.

[0020] In some embodiments, the aromatic glycidyl ether having at least two epoxy groups is bisphenol A epoxy resin or bisphenol F epoxy resin, and the aromatic glycidyl ether having at least two epoxy groups has an epoxy value of 80 to 120 and a dynamic viscosity of 100 cps to 900 cps at 25°C.

[0021] In some embodiments, the alicyclic epoxy resin having at least two epoxy groups is an epoxidized alicyclic olefin compound obtained by oxidizing an alicyclic olefin compound having two double bonds. The alicyclic epoxy resin having at least two epoxy groups has an epoxy value of 100 to 150 and a dynamic viscosity value of 85 cps to 1000 cps at 25°C.

[0022] In some embodiments, the epoxy resin includes an aromatic glycidyl ether having at least two epoxy groups and an alicyclic epoxy resin having at least two epoxy groups, and the mass ratio of the aromatic glycidyl ether having at least two epoxy groups to the alicyclic epoxy resin having at least two epoxy groups is 1 to 20:100.

[0023] In some embodiments, the cycloaliphatic epoxy resin having at least two epoxy groups is selected from one of Dow ERL-4211, Huntsman CY179, CY184, Daicel 2021p / 2021, Synasia S-06E, and Tytel TT21.

[0024] In some embodiments, the viscosity of the polyurethane acrylate resin is 5000 cps to 20000 cps.

[0025] In some embodiments, the active diluent monomer is selected from at least one of 1,2-epoxy-4-vinylcyclohexane, 3,4-epoxycyclohexyl methacrylate, tetrahydroindene diepoxide, 3,4-epoxycyclohexyl methacrylate, vinylcyclohexene dioxide, triethylene glycol divinyl ether, 3,3'-(oxybismethylene)bis(3-ethyl)oxetane, 3-ethyl-3-oxetane methanol, and diethylene glycol divinyl ether.

[0026] In some embodiments, the photoinitiator is a mixed photoinitiator consisting of a free radical photoinitiator and a cationic photoinitiator, and the mass ratio of the free radical photoinitiator to the cationic photoinitiator is 1 to 5:1.

[0027] In some embodiments, the free radical photoinitiator is at least one of benzoin and its derivatives, benzil ketal and its derivatives, acetophenone, dialkoxyacetophenone, α-hydroxyalkyl phenone, α-aminoalkyl phenone, esterified oxime ketone compound, acylphosphine oxide, aromatic peroxyester, halogenated methyl aromatic ketone, organic sulfur-containing compound, benzoylformate, benzophenone and its derivatives, thioxanthone or its derivatives, bisimidazole or camphorquinone.

[0028] In other embodiments, the free radical photoinitiator is at least one of benzoin methyl ether, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 2-methyl-1-(4-methylthiophenyl)-2-morpholine-1-propanone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2-phenylbenzyl-2-dimethylamine-1-(4-morpholinebenzylphenyl)butanone, dibenzophenone, and 2-isopropylthioxanthone.

[0029] In some embodiments, the cationic photoinitiator is selected from a diazonium salt, a diaryliodonium salt, a triarylsulfonium salt, an alkylsulfonium salt, an iron arene salt, a sulfonyloxyketone, and a triarylsiloxane. Preferably, the cationic photoinitiator is selected from Irgacure 261 or Irgacure 250.

[0030] In some embodiments, the thermal initiator is at least one of a cationic thermal curing agent, an imidazole curing agent, a dicyandiamide curing agent, and an acid anhydride curing agent. Preferably, the cationic thermal initiator includes one of an aromatic sulfonium salt, an aromatic iodonium salt, an aluminum complex, an aromatic diazonium salt, and a pyridinium salt. Preferably, the cationic thermal initiator includes at least one of a hexafluoroantimonate type and an amine-blocked Lewis acid salt.

[0031] In some embodiments, the filler is at least one of silica powder, alumina, barium titanate, talc, bentonite, mica, and aluminum hydroxide.

[0032] In some embodiments, the coupling agent is a silane coupling agent. Preferably, the coupling agent is at least one of γ-ureidopropyltriethoxysilane, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-aminopropyltriethoxysilane, vinyltriethoxysilane, and 3-glycidoxypropyltrimethoxysilane.

[0033] In some embodiments, the thixotropic agent is at least one of hydrophobic fumed silica, organic bentonite, hydrogenated castor oil, and polyvinyl alcohol.

[0034] In some embodiments, the pigment is carbon black.

[0035] In some embodiments, the auxiliary agent includes an adhesion promoter, a leveling agent, a defoaming agent, an antioxidant and a stabilizer, and the mass ratio of the adhesion promoter, the leveling agent, the defoaming agent, the antioxidant and the stabilizer is (1-5): (0.05-3): (0.1-5): (0.1-1): (0.1-3).

[0036] In some embodiments, the adhesion promoter includes at least one of hydroxyalkyl acrylate, acrylic acid, acrylate containing carboxyl functional groups, and phosphate containing unsaturated functional groups. Preferably, the adhesion promoter is one of Deqian 1121, Sartomer CD9051, Union Carbide's A-172 silane coupling agent, and methacrylate phosphate.

[0037] In some embodiments, the leveling agent is silicon-containing or non-silicon-containing. Preferably, the leveling agent is one of BYK333, BYK371, TEGO370, and TEGO410.

[0038] In some embodiments, the stabilizer is at least one of a ferrocene compound, an acid anhydride compound, and a phenol compound. Preferably, the ferrocene compound is ferrocene, methylferrocene, or ethylferrocene; the acid anhydride compound is phthalic anhydride, maleic anhydride, or succinic anhydride; and the phenol compound is hydroquinone, p-methoxyphenol, or 2,6-di-tert-butyl-p-cresol. Preferably, the stabilizer is ferrocene, methylferrocene, ethylferrocene, phthalic anhydride, hydroquinone, and / or p-methoxyphenol.

[0039] In some embodiments, the defoaming agent is the solvent-based defoaming agent 2700 or 3100 of Deqian Company, the defoaming agent Airex900 or Airex920 of Digao Company, etc.; preferably, the defoaming agent is the solvent-based defoaming agent 3100.

[0040] In some embodiments, the antioxidant is a hindered phenol compound. Preferably, the antioxidant is one of BHT, 2246, 1010, and 1076.

[0041] In a second aspect, an embodiment of the present application provides a method for preparing a UV thermal dual-curing adhesive, comprising:

[0042] Providing the components of the UV thermal dual-curing adhesive as described in the first aspect as raw materials;

[0043] Mixing, stirring, and grinding the photocurable prepolymer, the reactive diluent monomer, the filler, the coupling agent, and the pigment to obtain a mixed intermediate;

[0044] Under a yellow light environment, the photoinitiator, the thermal initiator and the auxiliary agent are added to the mixed intermediate to obtain the UV-heat dual-curing adhesive.

[0045] The UV-heat dual-cure adhesive and its preparation method provided in the present application achieve both high bond strength and weather resistance through the epoxy resin's rigid-flexible network, inorganic fillers to reduce thermal expansion, and dual-cure, staged stress release. Epoxy resin, as a dual-functional "framework-buffer" material, provides a low-shrinkage, thermal shock-resistant core carrier. This, combined with the acrylate interpenetrating network structure and filler-based composite effects, ensures reliability. Specifically, photocurable prepolymers are usually the basis of the UV-curing part, and epoxy resin provides structural strength, chemical resistance, etc.; reactive diluent monomers are used to adjust viscosity, participate in the curing reaction, and reduce shrinkage; photoinitiators are used to initiate UV curing, generate free radicals or cations, and start the polymerization reaction; thermal initiators initiate thermal curing of epoxy resins when heated to form a tighter network; fillers are used to reduce shrinkage, adjust the thermal expansion coefficient, and enhance mechanical properties. The filler has a low thermal expansion coefficient, which can reduce the overall linear expansion coefficient and improve resistance to cold and hot shocks; coupling agents enhance the interface bonding between fillers and resins, improve bonding strength and moisture and heat resistance; thixotropic agents prevent sagging during construction and improve operating performance; pigments are used for coloring; additives, including antioxidants, defoaming agents, leveling agents, etc., improve stability and processability.

[0046] In addition, UV curing quickly forms a preliminary structure, while thermal curing further crosslinks to improve final performance. Fillers and coupling agents reduce shrinkage, lower the coefficient of expansion, and enhance resistance to temperature fluctuations. Epoxy resin, as a prepolymer, provides mechanical strength and weather resistance, and dual curing may form an interpenetrating network to improve reliability. Epoxy resin, as the main backbone, provides high bond strength, chemical resistance, and weather resistance. Partial curing may occur during the UV curing stage, and further crosslinking may occur during the thermal curing stage, increasing the crosslink density and reducing internal stress, thereby reducing shrinkage and expansion coefficients while enhancing resistance to thermal shock. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0048] Figure 1 Schematic diagram of the process for preparing the UV thermal dual-curing adhesive provided in the embodiment of the present application. DETAILED DESCRIPTION

[0049] In the following description, specific details such as specific system structures and technologies are provided for illustration rather than limitation to facilitate a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the embodiments of the present application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the embodiments of the present application.

[0050] It should also be understood that the term "and / or" used in the description of the embodiments of the present application and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0051] It should be noted that when an element is referred to as being “fixed on” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or indirectly connected to the other element.

[0052] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0053] In addition, in the description of the embodiments of the present application and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0054] References to "some embodiments" or "some embodiments" described in the specification of the embodiments of the present application mean that one or more embodiments of the embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways. "Multiple" refers to two or more.

[0055] In a first aspect, an embodiment of the present application provides a UV-heat dual-curing adhesive, comprising the following components in percentage by mass:

[0056] Light-curing prepolymer 30% to 55%;

[0057] Active dilution monomer 5% to 25%;

[0058] Photoinitiator 1% to 10%;

[0059] Thermal initiator 1% to 20%;

[0060] Filler 10% to 40%;

[0061] Coupling agent 0.5% to 5%;

[0062] Thixotropic agent 1% to 10%;

[0063] Pigment 1% to 10%;

[0064] Additives 2% to 8%;

[0065] Wherein, the photocurable prepolymer includes epoxy resin.

[0066] The UV-heat dual-cure adhesive provided in this application achieves both high bond strength and weather resistance through the epoxy resin's flexible and rigid network, inorganic fillers that reduce thermal expansion, and the dual-cure, staged stress release process. Epoxy resin, as a dual-functional "framework-buffer" material, provides a low-shrinkage, thermal shock-resistant core carrier. This, combined with the acrylate interpenetrating network structure and filler-based composite effects, ensures reliability. Specifically, photocurable prepolymers are usually the basis of the UV-curing part, and epoxy resin provides structural strength, chemical resistance, etc.; reactive diluent monomers are used to adjust viscosity, participate in the curing reaction, and reduce shrinkage; photoinitiators are used to initiate UV curing, generate free radicals or cations, and start the polymerization reaction; thermal initiators initiate thermal curing of epoxy resins when heated to form a tighter network; fillers are used to reduce shrinkage, adjust the thermal expansion coefficient, and enhance mechanical properties. The filler has a low thermal expansion coefficient, which can reduce the overall linear expansion coefficient and improve resistance to cold and hot shocks; coupling agents enhance the interface bonding between fillers and resins, improve bonding strength and moisture and heat resistance; thixotropic agents prevent sagging during construction and improve operating performance; pigments are used for coloring; additives, including antioxidants, defoaming agents, leveling agents, etc., improve stability and processability.

[0067] In addition, UV curing quickly forms a preliminary structure, while thermal curing further crosslinks to improve final performance. Fillers and coupling agents reduce shrinkage, lower the coefficient of expansion, and enhance resistance to temperature fluctuations. Epoxy resin, as a prepolymer, provides mechanical strength and weather resistance, and dual curing may form an interpenetrating network to improve reliability. Epoxy resin, as the main backbone, provides high bond strength, chemical resistance, and weather resistance. Partial curing may occur during the UV curing stage, and further crosslinking may occur during the thermal curing stage, increasing the crosslink density and reducing internal stress, thereby reducing shrinkage and expansion coefficients while enhancing resistance to thermal shock.

[0068] In applications, the mass percentage of the photocurable prepolymer is any value within the range of 30% to 55%, such as 30%, 35%, 40%, 45%, 50%, 55%, etc., wherein the photocurable prepolymer includes an epoxy resin. The mass percentage of the reactive diluent monomer is any value within the range of 5% to 25%, such as 5%. The mass percentage of the photoinitiator is any value within the range of 1% to 10%, such as 1%. The mass percentage of the thermal initiator is any value within the range of 1% to 20%, such as 1%. The mass percentage of the filler is any value within the range of 10% to 40%, such as 10%, 12%, 15%, 18%, 20%, 25%, 28%, 30%, 35%, 40%. The mass percentage of the coupling agent is any value within the range of 0.5% to 5%, such as 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%. The mass percentage of the thixotropic agent is any value within the range of 1% to 10%, such as 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%. The mass percentage of the pigment is any value within the range of 1% to 10%, such as 1%. The mass percentage of the auxiliary agent is any value within the range of 2% to 8%, such as 2%, 3%, 4%, 5%, 6%, 7%, and 8%.

[0069] In some embodiments, the photocurable prepolymer further comprises a polyurethane acrylate resin, and the mass ratio of the epoxy resin to the polyurethane acrylate resin is 1 to 5:1. In some specific embodiments, the mass ratio of the epoxy resin to the polyurethane acrylate resin is any ratio within the range of 1 to 5:1, such as 1:1, 2:1, 3:2, 3:1, 4:1, 7:2, 9:2, or 5:1. In a preferred embodiment, the mass ratio of the epoxy resin to the polyurethane acrylate resin is 1:1. A high ratio of the polyurethane acrylate resin will increase overall curing shrinkage and negatively impact resistance to high temperature and humidity. A high ratio of the epoxy resin will reduce UV curing speed, increase hardness, deteriorate toughness, and decrease impact resistance. Therefore, the mass ratio of the epoxy resin to the polyurethane acrylate resin is preferably 1 to 5:1, and is preferably controlled at 1:1.

[0070] In some embodiments, the epoxy resin includes an aromatic glycidyl ether having at least two epoxy groups. Aromatic glycidyl ethers (containing a benzene ring structure) have a rigid benzene ring backbone and epoxy groups, resulting in high strength and heat resistance. The conjugated rigid structure of the benzene rings significantly increases the glass transition temperature, imparting excellent high-temperature creep resistance to the adhesive layer. The steric hindrance of the benzene rings inhibits thermal motion of the molecular chain, reducing the thermal expansion coefficient.

[0071] In some embodiments, the epoxy resin includes an alicyclic epoxy resin having at least two epoxy groups. Alicyclic epoxy resins (containing cyclic aliphatic hydrocarbons) include 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate (TTA21), dicyclopentadiene dioxide (ERL-4221), etc., which are cyclic aliphatic hydrocarbon skeletons + epoxy groups, without a benzene ring structure to avoid UV absorption, and have excellent weather resistance, making them suitable for optically transparent adhesives. The cyclic structure has both rigidity and flexibility, high low-temperature impact strength, and resistance to cold and hot cycles. Alicyclic epoxy groups have high reactivity, fast thermal curing, and are suitable for rapid production.

[0072] In some embodiments, the aromatic glycidyl ether having at least two epoxy groups is a bisphenol A epoxy resin or a bisphenol F epoxy resin, and the epoxy value of the aromatic glycidyl ether having at least two epoxy groups is 80 to 120, and the dynamic viscosity value at 25°C is 100cps to 900cps. Among them, bisphenol A epoxy resin or bisphenol F epoxy resin can be obtained by reacting epichlorohydrin with an aromatic alcohol or phenol. By precisely controlling the epoxy value (80-120) and viscosity (100-900cps), bisphenol A / F epoxy resin achieves an optimal balance between curing density, processability and mechanical properties. Bisphenol A focuses on high temperature and high strength scenarios, and bisphenol F adapts to flexible and high permeability requirements. The two are structurally customized through the epichlorohydrin controllable condensation process, ultimately supporting the high reliability performance of the adhesive in extreme environments.

[0073] It should be noted that the epoxy value refers to the number of moles of epoxy groups contained in every 100 grams of resin, usually expressed as eq / 100g. The epoxy value directly affects the crosslinking density of the resin, which in turn affects the mechanical properties, heat resistance and chemical stability after curing. A higher epoxy value means more epoxy groups, which can form a tighter crosslinking network, improve strength and heat resistance, but may increase brittleness. An epoxy value that is too low will lead to insufficient crosslinking, affecting performance. Dynamic viscosity reflects the fluidity of the resin. During the preparation of adhesives, viscosity affects the ease of mixing, coating and processing. Lower viscosity helps to evenly disperse fillers and other ingredients, but too low viscosity may cause sagging or storage stability problems. A dynamic viscosity value in the range of 100-900cps indicates that the resin has moderate fluidity at room temperature, which is convenient for processing while maintaining stability.

[0074] In some embodiments, the cycloaliphatic epoxy resin having at least two epoxy groups is an epoxidized cycloaliphatic olefin compound obtained by oxidizing an alicyclic olefin compound having two double bonds. The cycloaliphatic epoxy resin having at least two epoxy groups has an epoxy value of 100 to 150 and a dynamic viscosity of 85 cps to 1000 cps at 25°C. The cycloaliphatic epoxy resin having at least two epoxy groups has epoxy groups attached to the alicyclic ring, forming a compact, rigid molecular structure. After curing, the resin exhibits a high crosslinking density, a high heat deformation temperature, a Martin heat resistance temperature exceeding 190°C, a thermal decomposition temperature greater than 360°C, low cure shrinkage, high tensile strength, and good thermal stability.

[0075] In some embodiments, the epoxy resin includes an aromatic glycidyl ether having at least two epoxy groups and an alicyclic epoxy resin having at least two epoxy groups, wherein the mass ratio of the aromatic glycidyl ether having at least two epoxy groups to the alicyclic epoxy resin having at least two epoxy groups is 1 to 20:100. The aromatic glycidyl ether having at least two epoxy groups is used to adjust viscosity and performance, while the alicyclic epoxy resin having at least two epoxy groups is used for photocuring. Specifically, the aromatic and alicyclic epoxy resins are compounded in a ratio of 1 to 20:100, achieving an optimal balance between heat resistance, flexibility, and reliability through interpenetrating structural network reinforcement, segmented curing stress release, and precise control of the thermal expansion coefficient. Aromatic epoxy acts as a "rigidity enhancer" and a small amount of addition can significantly improve high-temperature performance and interface strength; alicyclic epoxy acts as a "flexible matrix" to ensure weather resistance and processability; when the two work together, the adhesive can simultaneously meet the harsh working conditions such as extreme temperatures, high-frequency vibrations and long-term aging, making it an ideal choice for precision electronics, optical devices and new energy fields.

[0076] In the application, the alicyclic epoxy resin having at least two epoxy groups is selected from one of Dow ERL-4211, Huntsman CY179, CY184, Daicel 2021p / 2021, Synasia S-06E and Tytel TT21.

[0077] In some embodiments, the viscosity of the polyurethane acrylate resin is 5000 cps to 20000 cps. The viscosity of the polyurethane acrylate resin is controlled within the range of 5000 to 20000 cps, which is resistant to sedimentation and controllable thixotropy, making it suitable for a variety of coating processes; uniform distribution at the nanoscale optimizes the thermal expansion coefficient and mechanical strength; staged stress release achieves low shrinkage and high reliability; and complements epoxy resin, significantly enhancing resistance to cold and hot shocks and durability. In application, the polyurethane acrylate resin is obtained by reacting a polyol with an excess of isocyanate to obtain an isocyanate-terminated prepolymer, which is then reacted with hydroxy acrylate. Since epoxy resin itself has rigidity and poor toughness after curing, polyurethane acrylate resin is used to adjust the toughness of the adhesive after curing. In application, Sartomer's CN969 NS, CN9021NS, CN9006NS, Lancolu L-6390, L-6900, etc. can be selected.

[0078] In some embodiments, the reactive diluent monomer is selected from at least one of 1,2-epoxy-4-vinylcyclohexane, 3,4-epoxycyclohexyl methacrylate, tetrahydroindene diepoxide, 3,4-epoxycyclohexyl methacrylate, vinylcyclohexene dioxide, triethylene glycol divinyl ether, 3,3'-(oxybismethylene)bis(3-ethyl)oxetane, 3-ethyl-3-oxetanol, and diethylene glycol divinyl ether. These reactive diluent monomers are used to adjust the viscosity of the adhesive and promote the curing reaction.

[0079] In some embodiments, the photoinitiator is a mixed photoinitiator consisting of a free radical photoinitiator and a cationic photoinitiator, and the mass ratio of the free radical photoinitiator to the cationic photoinitiator is 1 to 5:1. This achieves a synergistic dual polymerization mechanism, that is, the free radical photoinitiator initiates the free radical polymerization of the acrylate monomer / prepolymer, quickly forming a surface cured layer and providing initial strength. The cationic photoinitiator triggers the cationic ring-opening polymerization of the epoxy resin, continuing deep curing (post-curing effect) to form a dense cross-linked network. In some specific embodiments, the mass ratio of the free radical photoinitiator to the cationic photoinitiator is 1:1, 2:1, 3:2, 3:1, 4:1, 7:2, 9:2, 5:1, or any other ratio within the range of 1 to 5:1. In a preferred embodiment, the mass ratio of the free radical photoinitiator to the cationic photoinitiator is 1:1. In other embodiments, the free radical photoinitiator and the cationic photoinitiator can be mixed in any ratio.

[0080] In some embodiments, the free radical photoinitiator is at least one of benzoin and its derivatives, benzil ketal and its derivatives, acetophenone, dialkoxyacetophenone, α-hydroxyalkyl phenone, α-aminoalkyl phenone, esterified oxime ketone compound, acylphosphine oxide, aromatic peroxyester, halogenated methyl aromatic ketone, organic sulfur-containing compound, benzoylformate, benzophenone and its derivatives, thioxanthone or its derivatives, bisimidazole or camphorquinone.

[0081] In other embodiments, the free radical photoinitiator is at least one of benzoin methyl ether, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 2-methyl-1-(4-methylthiophenyl)-2-morpholine-1-propanone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2-phenylbenzyl-2-dimethylamine-1-(4-morpholinebenzylphenyl)butanone, dibenzophenone, and 2-isopropylthioxanthone.

[0082] In some embodiments, the cationic photoinitiator is selected from a diazonium salt, a diaryliodonium salt, a triarylsulfonium salt, an alkylsulfonium salt, an iron arene salt, a sulfonyloxyketone, and a triarylsiloxane. Preferably, the cationic photoinitiator facilitates epoxy ring-opening polymerization and improves adhesion between the colloid and the substrate. Preferably, the cationic photoinitiator is selected from Irgacure 261 or Irgacure 250.

[0083] In some embodiments, the thermal initiator is at least one of a cationic thermal curing agent, an imidazole curing agent, a dicyandiamide curing agent, and an acid anhydride curing agent. Preferably, the cationic thermal initiator comprises one of an aromatic sulfonium salt, an aromatic iodonium salt, an aluminum complex, an aromatic diazonium salt, and a pyridinium salt. Preferably, the cationic thermal initiator comprises at least one of a hexafluoroantimonate salt and an amine-blocked Lewis acid salt.

[0084] In some embodiments, the filler is at least one of silica powder, alumina, barium titanate, talc, bentonite, mica, and aluminum hydroxide. In practice, the filler particle size ranges from 300 to 500 μm. Exceeding this range, if the particle size is too large, will affect the dispensing process, while if the particle size is too small, it will significantly thicken the adhesive, both of which are detrimental to the application process. Fillers serve to increase the curing strength of the adhesive and to control the thermal expansion coefficient. In practical applications, multiple fillers of different particle sizes can be combined to achieve optimal results.

[0085] In some embodiments, the coupling agent is a silane coupling agent. Preferably, the coupling agent is at least one of γ-ureidopropyltriethoxysilane, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-aminopropyltriethoxysilane, vinyltriethoxysilane, and 3-glycidoxypropyltrimethoxysilane.

[0086] In some embodiments, the thixotropic agent is at least one of hydrophobic fumed silica, organic bentonite, hydrogenated castor oil, and polyvinyl alcohol.

[0087] In some embodiments, the pigment is carbon black.

[0088] In some embodiments, the additives include an adhesion promoter, a leveling agent, a defoaming agent, an antioxidant and a stabilizer, and the mass ratio of the adhesion promoter, the leveling agent, the defoaming agent, the antioxidant and the stabilizer is (1-5): (0.05-3): (0.1-5): (0.1-1): (0.1-3).

[0089] In some embodiments, the adhesion promoter includes at least one of hydroxyalkyl acrylate, acrylic acid, acrylate containing carboxyl functional groups, and phosphate containing unsaturated functional groups. Preferably, the adhesion promoter is one of Deqian 1121, Sartomer CD9051, Union Carbide's A-172 silane coupling agent, and methacrylate phosphate.

[0090] In some embodiments, the leveling agent is silicon-containing or non-silicon-containing. Preferably, the leveling agent is one of BYK333, BYK371, TEGO370, and TEGO410.

[0091] In some embodiments, the stabilizer is at least one of a ferrocene compound, an acid anhydride compound, and a phenol compound. Preferably, the ferrocene compound is ferrocene, methylferrocene, or ethylferrocene; the acid anhydride compound is phthalic anhydride, maleic anhydride, or succinic anhydride; and the phenol compound is hydroquinone, p-methoxyphenol, or 2,6-di-tert-butyl-p-cresol. Preferably, the stabilizer is ferrocene, methylferrocene, ethylferrocene, phthalic anhydride, hydroquinone, and / or p-methoxyphenol.

[0092] In some embodiments, the defoaming agent is the solvent-based defoaming agent 2700 or 3100 produced by Deqian Company, the defoaming agent Airex900 or Airex920 produced by Digao Company, etc.; preferably, the defoaming agent is the solvent-based defoaming agent 3100.

[0093] In some embodiments, the antioxidant is a hindered phenolic compound. Preferably, the antioxidant is one of BHT, 2246, 1010, and 1076.

[0094] The UV heat dual-curing adhesive provided in the embodiment of the present application is a dual-curing adhesive with low shrinkage and low thermal expansion coefficient obtained by optimizing the prepolymer structure and combining the components. The prepared adhesive can be quickly cured under 365nm ultraviolet light from an LED, or can be thermally cured at low temperatures of 80°C. The product is resistant to high and low temperature cycling impacts of -50°C to 140°C and has good application prospects. Among them, when the UV heat dual-curing adhesive provided in the embodiment of the present application is applied to cameras on mobile phones, security systems, and vehicles, the UV curing time is 10 to 15 seconds and the curing energy is 2000mj / cm 2 The curing shrinkage rate (UV+heat curing) is 1.2%, and the temperature resistance range is -50℃~140℃ for one cycle of 30min, lasting 100h.

[0095] The present application also provides a method for preparing a UV heat dual curing adhesive, such as Figure 1 As shown, including:

[0096] S10, providing the components of the UV thermal dual-curing adhesive as described in the first aspect as raw materials;

[0097] S20, mixing, stirring, and grinding the photocurable prepolymer, reactive diluent monomer, filler, coupling agent, thixotropic agent, and pigment to obtain a mixed intermediate;

[0098] S30. Under yellow light, add a photoinitiator, a thermal initiator, and an auxiliary agent to the mixed intermediate to obtain the UV-heat dual-curing adhesive.

[0099] The preparation method of the UV-heat dual-curing adhesive provided in the embodiment of the present application achieves ultra-uniform dispersion of multi-phase components through high-shear mixing-precision grinding, and strictly avoids pre-curing risks in a yellow light environment, ultimately ensuring the low shrinkage and resistance to cold and hot shock of the adhesive. The coordinated dispersion structure of epoxy resin and filler and the precise control of the light / heat curing process are the core process guarantees for achieving high reliability.

[0100] In some embodiments, in step S20, the role of mixing and stirring includes uniformly dispersing the components, especially the mixing between fillers, pigments and prepolymers. If the stirring is insufficient, the filler may clump, affecting the performance of the final product, such as mechanical strength or thermal expansion coefficient. Grinding can further refine the particles, ensure that the fillers and pigments are more evenly dispersed, and improve the stability and performance of the adhesive. Furthermore, during the grinding operation, the mixture of the components needs to be ground to a fineness of 2 to 30 microns, specifically 2μm, 4μm, 6μm, 8μm, 10μm, 12μm, 14μm, 16μm, 20μm, 22μm, 24μm, 26μm, 27μm, 28μm, 30μm, etc., any value within the range of 2 to 30 microns.

[0101] In step S30, UV-curable adhesives are typically sensitive to ultraviolet light under yellow light. Photoinitiators also react to visible light, particularly during the mixing process. This can cause premature polymerization, leading to decreased storage stability or partial curing before application, impacting the final curing effect. Yellow light prevents the photoinitiator from reacting, thus ensuring that after the photoinitiator is added, the adhesive will not prematurely cure during storage or transportation.

[0102] Example

[0103] Example 1

[0104] The present application also provides a UV heat dual curing adhesive and a preparation method thereof. The preparation method of the UV heat dual curing adhesive includes the following steps:

[0105] S10, providing the components of the UV thermal dual-curing adhesive as described in the first aspect as raw materials;

[0106] Provide 35g of epoxy resin (bisphenol A epoxy resin, model epon828, manufacturer HEXION, epoxy value 0.52~0.54eq / 100g, viscosity value 11000~15000cps), 35g of polyurethane acrylate resin (viscosity 8700cps, model CN980NS, manufacturer Sartomer), 10g of 1,2-epoxy-4-vinylcyclohexane as active diluent monomer, 1.5g of γ-ureidopropyltriethoxysilane as coupling agent; 3g of hydrophobic fumed silica as thixotropic agent (model fumed silica A200, manufacturer Evonik) Company, particle size is 0.3um), 5g carbon black as pigment, 2g α-hydroxyalkyl phenone and 2g 1-hydroxycyclohexyl phenyl ketone as photoinitiator, 100g alumina as filler (model BAK-10, manufacturer is Baitu Co., Ltd.), 1.5g hexafluoroantimonate type as thermal initiator (model ICAM-8409, manufacturer Shenzhen Chuchuang Applied Materials Co., Ltd.), 1.5g Deqian 1121 as adhesion promoter, 1g BYK333 as leveling agent, 0.5g ethyl ferrocene as stabilizer, 1g Deqian Company's solvent-based foaming agent 2700 as defoaming agent, 0.3g hindered phenol 2246 as antioxidant;

[0107] S20, 35 g of bisphenol A epoxy resin, 35 g of polyurethane acrylate resin, 10 g of 1,2-epoxy-4-vinylcyclohexane, 1.5 g of γ-ureidopropyltriethoxysilane, 3 g of hydrophobic fumed silica, and 5 g of carbon black as a pigment were mixed and stirred for 1 hour, and ground to obtain a mixed intermediate with a fineness of 10 μm;

[0108] S30, adding a photoinitiator, a thermal initiator, and an auxiliary agent to the mixed intermediate under a yellow light environment to obtain the UV thermal dual curing adhesive;

[0109] Under 570nm yellow light environment, 2g of α-hydroxyalkyl phenone and 2g of 1-hydroxycyclohexyl phenyl ketone were added, and finally 100g of aluminum oxide, 1.5g of hexafluoroantimonate type and 1.5 of Deqian 1121, 1g of leveling agent BYK333, 0.5g of ethyl ferrocene, 1g of Deqian's solvent-based foaming agent 2700, and 0.3g of hindered phenol 2246 were added to obtain a UV thermal dual-curing adhesive.

[0110] Example 2

[0111] The present application also provides a UV heat dual curing adhesive and a preparation method thereof. The preparation method of the UV heat dual curing adhesive includes the following steps:

[0112] S10, providing the components of the UV thermal dual-curing adhesive as described in the first aspect as raw materials;

[0113] Provide 25g of epoxy resin (bisphenol A epoxy resin, model epon828, manufacturer HEXION, epoxy value 0.52~0.54eq / 100g, viscosity value 11000~15000cps), 25g of polyurethane acrylate resin (viscosity 8700cps, model CN980NS, manufacturer Sartomer), 8g of 1,2-epoxy-4-vinylcyclohexane as active diluent monomer, 1.5g of γ-ureidopropyltriethoxysilane as coupling agent; 3g of hydrophobic fumed silica as thixotropic agent (model fumed silica A200, manufacturer Evonik) , particle size of 0.3um), 5g carbon black as pigment, 2.5g α-hydroxyalkyl phenyl ketone and 2.5g 1-hydroxycyclohexyl phenyl ketone as photoinitiator, 100g alumina as filler (model BAK-10, manufacturer Baitu Co., Ltd.), 2g hexafluoroantimonate type as thermal initiator (model ICAM-8409, manufacturer Shenzhen Chuchuang Applied Materials Co., Ltd.), 1g Deqian 1121 as adhesion promoter, 1g BYK333 as leveling agent, 0.5g ethyl ferrocene as stabilizer, 1g Deqian's solvent-based foaming agent 2700 as defoaming agent, and 0.5g hindered phenol 2246 as antioxidant;

[0114] S20, 25 g of bisphenol A epoxy resin, 25 g of polyurethane acrylate resin, 8 g of 1,2-epoxy-4-vinylcyclohexane, 1.5 g of γ-ureidopropyltriethoxysilane, 3 g of hydrophobic fumed silica, and 5 g of carbon black as a pigment were mixed and stirred for 1 hour, and ground to obtain a mixed intermediate with a fineness of 10 μm;

[0115] S30, adding a photoinitiator, a thermal initiator, and an auxiliary agent to the mixed intermediate under a yellow light environment to obtain the UV thermal dual curing adhesive;

[0116] Under 570nm yellow light environment, 2.5g of α-hydroxyalkyl phenone and 2.5g of 1-hydroxycyclohexyl phenyl ketone were added, and finally 100g of aluminum oxide, 2g of hexafluoroantimonate type and 1.5 of Deqian 1121, 1g of leveling agent BYK333, 0.5g of ethyl ferrocene, 1g of Deqian's solvent-based foaming agent 2700, and 0.5g of hindered phenol 2246 were added to obtain a UV thermal dual-curing adhesive.

[0117] Example 3

[0118] The present application also provides a UV heat dual curing adhesive and a preparation method thereof. The preparation method of the UV heat dual curing adhesive includes the following steps:

[0119] S10, providing the components of the UV thermal dual-curing adhesive as described in the first aspect as raw materials;

[0120] Provide 10g epoxy resin (bisphenol A epoxy resin, model Phoenix Epoxy E-51, manufacturer Nantong Xingchen Synthetic Materials Co., Ltd., epoxy value 0.51~0.53eq / 100g, viscosity 3100~7000cps), 25g alicyclic epoxy resin (Dow ERL-4211, epoxy value 7.0-7.9eq / kg, viscosity 250~450cps), 35g polyurethane acrylate resin (viscosity 5000~12000cps, model L-6390, manufacturer Guangdong Lan Kelu New Materials Co., Ltd.), 10g triethylene glycol divinyl ether as active diluent monomer, 1.5g γ-ureidopropyl triethoxysilane as coupling agent; 3g hydrophobic gas phase di Silicon oxide as a thixotropic agent (model: fumed silica R976, manufacturer: Evonik, particle size: 0.2 μm), 5 g of carbon black as a pigment, 2.5 g of α-hydroxyalkyl phenone and 2.5 g of 1-hydroxycyclohexyl phenyl ketone as photoinitiators, 100 g of alumina as a filler (model: BAK-20, manufacturer: Baitu Co., Ltd.), 2 g of hexafluoroantimonate type as a thermal initiator (model: ICAM-8409, manufacturer: Shenzhen Chuchuang Applied Materials Co., Ltd.), 1 g of Deqian 1121 as an adhesion promoter, 1 g of BYK333 as a leveling agent, 0.5 g of ethyl ferrocene as a stabilizer, 1 g of Deqian's solvent-based foaming agent 2700 as a defoaming agent, and 0.5 g of hindered phenol 2246 as an antioxidant;

[0121] S20, 10 g of bisphenol A epoxy resin, 25 g of alicyclic epoxy resin, 35 g of polyurethane acrylate resin, 10 g of triethylene glycol divinyl ether, 1.5 g of γ-ureidopropyltriethoxysilane, 3 g of hydrophobic fumed silica, and 5 g of carbon black as a pigment were mixed and stirred for 1 h, and ground to obtain a mixed intermediate with a fineness of 10 μm;

[0122] S30, adding a photoinitiator, a thermal initiator, and an auxiliary agent to the mixed intermediate under a yellow light environment to obtain the UV thermal dual curing adhesive;

[0123] Under 570nm yellow light environment, 2.5g of α-hydroxyalkyl phenone and 2.5g of 1-hydroxycyclohexyl phenyl ketone were added, and finally 100g of aluminum oxide, 2g of hexafluoroantimonate type and 1.5 of Deqian 1121, 1g of leveling agent BYK333, 0.5g of ethyl ferrocene, 1g of Deqian's solvent-based foaming agent 2700, and 0.5g of hindered phenol 2246 were added to obtain a UV thermal dual-curing adhesive.

[0124] Example 4

[0125] The present application also provides a UV heat dual curing adhesive and a preparation method thereof. The preparation method of the UV heat dual curing adhesive includes the following steps:

[0126] S10, providing the components of the UV thermal dual-curing adhesive as described in the first aspect as raw materials;

[0127] Provide 35g epoxy resin (model is Japan Daicel 2021p / 2021, epoxy value is 7.0-7.9eq / kg, viscosity is 250-450cps), 35g polyurethane acrylate resin (viscosity is 5000-12000cps, model is L-6390, manufacturer is Guangdong Lan Kelu New Materials Co., Ltd.), 10g 3,4-epoxycyclohexyl methacrylate as active diluent monomer, 1.5g γ-ureidopropyl triethoxysilane as coupling agent, 2.5g hydrophobic fumed silica as thixotropic agent (model is fumed silica R976, manufacturer is Evonik, particle size is 0.2um), 5g carbon black as pigment, 3g α-hydroxyalkyl phenyl ketone and 2.5g 1-hydroxycyclohexyl phenyl ketone as photoinitiator, 100g alumina as filler (model BAK-20, manufacturer Baitu Co., Ltd.), 2g hexafluoroantimonate type as thermal initiator (model ICAM-8409, manufacturer Shenzhen Chuchuang Applied Materials Co., Ltd.), 1g Deqian 1121 as adhesion promoter, 1g BYK333 as leveling agent, 0.5g ethyl ferrocene as stabilizer, 1g Deqian's solvent-based foaming agent 2700 as defoaming agent, 0.5g hindered phenol 2246 as antioxidant;

[0128] S20, 35g of epoxy resin, 35g of polyurethane acrylate resin, 10g of 3,4-epoxycyclohexyl methacrylate, 1.5g of γ-ureidopropyltriethoxysilane, 3g of hydrophobic fumed silica, and 5g of carbon black as a pigment were mixed and stirred for 1h, and ground to obtain a mixed intermediate with a fineness of 10μm;

[0129] S30, adding a photoinitiator, a thermal initiator, and an auxiliary agent to the mixed intermediate under a yellow light environment to obtain the UV thermal dual curing adhesive;

[0130] Under 570nm yellow light environment, 3g of α-hydroxyalkyl phenone and 2.5g of 1-hydroxycyclohexyl phenyl ketone were added, and finally 100g of aluminum oxide, 2g of hexafluoroantimonate type and 1.5 of Deqian 1121, 1g of leveling agent BYK333, 0.5g of ethyl ferrocene, 1g of Deqian's solvent-based foaming agent 2700, and 0.5g of hindered phenol 2246 were added to obtain a UV thermal dual-curing adhesive.

[0131] Comparative Example

[0132] Comparative Example 1

[0133] This comparative example is basically the same as Example 3, except that acrylate resin is used instead of polyurethane acrylate resin.

[0134] Performance Testing

[0135] The performance tests were conducted on the UV heat dual curing adhesives of Examples 1 to 4 and Comparative Example 1. The specific test methods are as follows:

[0136] Viscosity: Test the dynamic viscosity at 25°C according to GBT2794-1995-Determination of viscosity of adhesives;

[0137] Preparation method of tensile strength and elongation at break test specimens: Use a polytetrafluoroethylene container with a wedge-shaped groove with a depth of 2 mm, a length of 25 cm, and a width of 20 cm. Evenly pour the UV heat dual-curing adhesive into the polytetrafluoroethylene container, then place the sample under a 365 nm (110 W) LED UV lamp for curing for 10 seconds, then heat and cure at 80 ° C for 30 minutes, take out, and obtain the test specimen. After cutting, tensile strength and elongation at break tests are performed.

[0138] Application performance testing:

[0139] The camera module fixing sample was made with UV heat dual curing adhesive. The camera module and the fixing base were both made of PC. A 22-gauge needle was used to glue the camera module around the contact area with the base. The camera module was cured with a 365nm (110W) LED UV lamp for 10s (curing energy 2000mj / cm 2), then heat and cure at 80℃×30min to obtain samples, and test related properties:

[0140] 1. Push Test: The push-pull tester is based on the principle of mechanics, namely the relationship between force and displacement. The push-pull tester applies a push or pull force to the test sample and measures the displacement caused by the force. The force value and the phenomenon after the test are used to test the bond strength of the adhesive, thereby determining the strength and durability of the sample.

[0141] A. Make at least 3 camera module samples

[0142] B. Install the sample: Install the prepared camera module on the test platform of the push-pull test machine

[0143] C. Test: Generate thrust by controlling voltage, record the thrust when the camera module is pushed away from the fixed base, and repeat the test multiple times to ensure the accuracy of the results.

[0144] 2. Hot and cold shock test (-50~140℃): The hot and cold shock test chamber is mainly used to test the performance of items in a rapid hot and cold alternation environment. The test process is generally as follows:

[0145] A. Place the item to be tested in a thermal shock test chamber and set the chamber to the required temperature range of -50 to 140°C and temperature change rate.

[0146] B. Preheating stage: Preheat the test chamber to the set temperature and maintain it for a period of time to reach a stable state.

[0147] C. Shock test: Perform hot and cold shock tests within the set temperature range. One hot and cold cycle is 0.5 hours, and the shock test cycle is 100 hours.

[0148] D. Test completion: After the test is completed, the test chamber temperature is restored to normal temperature, and the test items are removed for inspection and evaluation.

[0149] 3. Double 85 test: The use of the double 85 test chamber mainly includes the following steps:

[0150] A. Equipment installation: Place the test chamber on a stable surface and ensure the connection of power supply and drainage pipes.

[0151] B. Set test conditions: According to the requirements of the sample to be tested, set the test chamber temperature to 85±2℃ and humidity to 85%RH±5%RH.

[0152] C. Sample placement: Place the sample to be tested on the sample rack in the test chamber and ensure the stability and safety of the sample.

[0153] D. Start the test: Start the test chamber and conduct the test according to the set time.

[0154] E. Data analysis: Based on the test results, evaluate the performance and quality of the tested samples.

[0155] 4. Water absorption test: Water absorption is a measure of the degree to which a substance absorbs water. It refers to the percentage of mass increase when a substance is immersed in water for a certain period of time at a certain temperature. The test method is as follows:

[0156] A. Sample: Use a 50±1mm×3±2mm diameter disc for testing, with no less than 3 samples

[0157] B. Method: First, accurately weigh the sample to the nearest 0.001g. After UV and heat curing, cool to room temperature and weigh the sample as m1. Then, immerse the sample in distilled water at 23±0.5 degrees for 24 hours. After taking it out and drying it, weigh the sample again to the nearest 0.001g as m2. Finally, calculate according to the formula: Wm=(m2–m1) / m1×100%. The sample results are expressed as the arithmetic mean.

[0158] 5. Volume shrinkage test: Volume shrinkage is the ratio of the volume difference before and after curing of the resin system to the volume before curing. It can be expressed as the percentage of the ratio of the density difference before and after curing of the resin system to the density after curing. The test is performed using the pycnometer method:

[0159] A. Sample: Weigh 25g of sample, and after UV and heat curing, cool to room temperature. The sample should be no less than 3

[0160] B. Using 25°C pure water as a reference, calculate the exact volume of the pycnometer. Then use the pycnometer to measure the density of the resin before and after curing, and calculate the volume shrinkage of the cured resin according to the following formula:

[0161] Curing shrinkage = (1 – ρ before / ρ after) × 100%

[0162] Where: ρpre is the resin density before curing, g / cm 3 ; ρ is the density of the cured resin, g / cm 3 .

[0163] Test results

[0164] Table 1 Performance test data

[0165] Example Viscosity tensile strength Elongation at break Example 1 46000cps 10.5kg 11％ Example 2 52000cps 12.4kg 8％ Example 3 38000cps 11.8kg 15％ Example 4 42000cps 10.2kg 12％ Comparative Example 1 45000cps 5.8kg 22％

[0166] Table 1 reveals the dual-cure system's ability to regulate adhesive performance - through the rational design of viscosity (38,000 to 52,000 cps), the examples achieve a balance between tensile strength (10.2 to 12.4 kg) and elongation at break (8% to 15%), while the comparative examples significantly deteriorate in performance due to deviations in the technical route. The overall performance of Example 3 is particularly outstanding, reflecting the technical advantages of formula optimization. Example 2 has the highest viscosity: 52,000 cps, showing the highest tensile strength (12.4 kg), but the lowest elongation at break (8%), indicating that the high-viscosity system is more rigid but has reduced toughness. Example 3 has the lowest viscosity: 38,000 cps, the tensile strength is still relatively high (11.8 kg), and the elongation at break is optimal (15%), indicating that strength and flexibility can be taken into account through formula optimization. The tensile strength of Comparative Example 1 is 5.8 kg, which is significantly lower than that of the examples. Because the dual-cure system is not used, the mechanical properties collapse. Its elongation at break is as high as 22%, because the use of polyurethane acrylate results in a loose network structure, low strength but artificially high ductility. The viscosity of Examples 1-4 is concentrated in the range of 38,000 to 52,000 cps, the tensile strength is all greater than 10 kg, and the elongation at break is controlled at 8% to 15%, indicating that the strength-toughness balance is achieved through the synergy of dual curing and the optimization of the filler / resin ratio. Example 3 has the best comprehensive performance: moderate viscosity (38,000 cps), strength close to the maximum value (11.8 kg), and optimal flexibility (15% elongation at break), which is suitable for high strain scenarios (such as flexible electronics).

[0167] Table 2 Application performance test data

[0168]

[0169] According to the analysis in Table 2, the data verifies the core advantages of the UV thermal dual-curing adhesive design. Through light-heat segmented curing, filler-thermal expansion regulation and hydrophobic interface construction, the examples comprehensively surpass the comparative examples in key indicators such as thrust, shrinkage, and weather resistance. Example 3 has the best comprehensive performance (thrust 5.8kg, shrinkage 1.2%, water absorption 0.02%), making it an ideal choice for high-reliability applications, while the failure of comparative example 1 warns of the risks of single curing systems and formula defects. The thrust of Examples 1 to 4 is between 5.1kg and 5.8kg, while that of Comparative Example 1 is only 3.8kg, which is significantly lower. In terms of shrinkage, the examples are between 1.2% and 1.6%, while Comparative Example 1 is as high as 4.6%. The water absorption of the examples is between 0.02% and 0.08%, while that of Comparative Example 1 is 0.38%. All examples passed the hot and cold shock test, and Comparative Example 1 also passed, but in the double 85 test, Comparative Example 1 fell off, while all examples passed the test.

[0170] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0171] The above-described embodiments are only used to illustrate the technical solutions of the embodiments of the present application, rather than to limit them. Although the embodiments of the present application are described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the embodiments of the present application, and should all be included in the protection scope of the embodiments of the present application.

Claims

1. A UV heat dual curing adhesive, characterized in that: The following components are included in mass percentage: Light-curing prepolymer 30% to 55%; Active dilution monomer 5% to 25%; Photoinitiator 1% to 10%; Thermal initiator 1% to 20%; Filler 10% to 40%; Coupling agent 0.5% to 5%; Thixotropic agent 1% to 10%; Pigment 1% to 10%; Additives 2% to 8%; Wherein, the photocurable prepolymer includes epoxy resin.

2. The UV heat dual curing adhesive according to claim 1, characterized in that The photocurable prepolymer further comprises polyurethane acrylate resin, and the mass ratio of the epoxy resin to the polyurethane acrylate resin is 1 to 5:

1.

3. The UV heat dual curing adhesive according to claim 1, characterized in that: The epoxy resin includes an aromatic glycidyl ether having at least two epoxy groups; And / or, the epoxy resin includes an alicyclic epoxy resin having at least two epoxy groups.

4. The UV heat dual curing adhesive according to claim 3, characterized in that: The aromatic glycidyl ether having at least two epoxy groups is bisphenol A epoxy resin or bisphenol F epoxy resin. The epoxy value of the aromatic glycidyl ether having at least two epoxy groups is 80-120, and the dynamic viscosity value at 25° C. is 100 cps-900 cps.

5. The UV heat dual curing adhesive according to claim 3, characterized in that: The alicyclic epoxy resin having at least two epoxy groups is an epoxidized alicyclic olefin compound obtained by oxidizing an alicyclic olefin compound having two double bonds. The alicyclic epoxy resin having at least two epoxy groups has an epoxy value of 100 to 150 and a dynamic viscosity of 85 cps to 1000 cps at 25°C.

6. The UV heat dual curing adhesive according to claim 1, characterized in that: The epoxy resin includes an aromatic glycidyl ether having at least two epoxy groups and an alicyclic epoxy resin having at least two epoxy groups, and the mass ratio of the aromatic glycidyl ether having at least two epoxy groups to the alicyclic epoxy resin having at least two epoxy groups is 1 to 20:

100.

7. The UV heat dual curing adhesive according to claim 2, characterized in that: The viscosity of the polyurethane acrylate resin is 5000 cps to 20000 cps.

8. The UV heat dual curing adhesive according to any one of claims 1 to 7, characterized in that: The active diluent monomer is selected from at least one of 1,2-epoxy-4-vinylcyclohexane, 3,4-epoxycyclohexyl methacrylate, tetrahydroindene diepoxide, 3,4-epoxycyclohexyl methacrylate, vinylcyclohexene dioxide, triethylene glycol divinyl ether, 3,3'-(oxybismethylene)bis(3-ethyl)oxetane, 3-ethyl-3-oxetane methanol, and diethylene glycol divinyl ether; And / or, the photoinitiator is a mixed photoinitiator consisting of a free radical photoinitiator and a cationic photoinitiator, and the mass ratio of the free radical photoinitiator to the cationic photoinitiator is 1 to 5:1; And / or, the thermal initiator is at least one of a cationic thermal curing agent, an imidazole curing agent, a dicyandiamide curing agent, and an acid anhydride curing agent; And / or, the filler is at least one of silicon micropowder, aluminum oxide, barium titanate, talc, bentonite, mica, and aluminum hydroxide; And / or, the coupling agent is a silane coupling agent, including at least one of γ-ureidopropyltriethoxysilane, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-aminopropyltriethoxysilane, vinyltriethoxysilane, and 3-glycidoxypropyltrimethoxysilane; And / or, the thixotropic agent is at least one of hydrophobic fumed silica, organic bentonite, hydrogenated castor oil, and polyvinyl alcohol; and / or, the pigment is carbon black; And / or, the auxiliary agent includes an adhesion promoter, a leveling agent, a defoaming agent, an antioxidant and a stabilizer, and the mass ratio of the adhesion promoter, the leveling agent, the defoaming agent, the antioxidant and the stabilizer is (1-5): (0.05-3): (0.1-5): (0.1-1): (0.1-3).

9. The UV heat dual curing adhesive according to claim 8, characterized in that: The adhesion promoter is selected from at least one of hydroxyalkyl acrylate, acrylic acid, acrylate containing carboxyl functional group, and phosphate containing unsaturated functional group; The leveling agent includes at least one of BYK333, BYK371, TEGO370, and TEGO410; The stabilizer is at least one of ferrocene compounds, acid anhydride compounds and phenol compounds.

10. A method for preparing a UV thermal dual curing adhesive, characterized in that: include: Providing the components of the UV heat dual curing adhesive according to any one of claims 1 to 9 as raw materials; Mixing, stirring, and grinding the photocurable prepolymer, the reactive diluent monomer, the filler, the coupling agent, the thixotropic agent, and the pigment to obtain a mixed intermediate; Under a yellow light environment, the photoinitiator, the thermal initiator and the auxiliary agent are added to the mixed intermediate to obtain the UV-heat dual-curing adhesive.

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