Ultraviolet curing epoxy packaging ink with high reliability and low moisture penetrability as well as preparation method and application of ultraviolet curing epoxy packaging ink

Abstract

The invention belongs to the technical field of organic thin films, particularly discloses a UV-curable high polymer material, and particularly relates to high-reliability low-moisture-penetrability UV-curable epoxy packaging ink and a preparation method and application thereof.The ink is prepared from, by weight, 40-60 parts of epoxy silane monomers, 3-8 parts of epoxy oligomer resin and 5-15 parts of alicyclic epoxy monomers, 10-20 parts of a diluent, 0-0.5 part of a curing accelerator, 1-5 parts of a photoacid generator and 0.5-3 parts of a photosensitizer. The epoxy silane coupling agent is used as a main body material, can participate in crosslinking in a high proportion in a curing reaction, endows the film with high conversion rate, stability and excellent adhesive force, has the advantages of high heat resistance, chemical resistance, effective water and oxygen blocking and the like, and solves the problems of brittleness and the like of the film by introducing other components for compounding. And an innovative and effective solution is provided for reliable packaging of electronic devices.

Description

Technical Field

[0001] The invention belongs to the technical field of organic thin films, and specifically relates to a UV-curable polymer material, and specifically relates to a high-reliability, low-moisture-permeability UV-curable epoxy packaging ink, and a preparation method and application thereof. Background Art

[0002] Thin film encapsulation technology plays a vital role in the fields of electronic components and OLED organic materials. Large-scale integrated circuits, OLED displays and other components are usually required to be encapsulated and insulated to ensure their normal operation from external factors such as dust, moisture, shock, vibration and chemicals in the atmosphere. Especially for OLED organic materials, because they are extremely sensitive to water vapor and oxygen, effective encapsulation methods must be used to avoid contact between the device and water and oxygen to reduce the aging rate and extend the service life. In addition, encapsulation is not only related to the insulation problem of electronic components, but also has an important impact on their size, heat dissipation and cost. The packaging method has become one of the key factors affecting the performance of electronic components, and may even become a new performance growth point. In the packaging process, in addition to the packaging method, suitable packaging materials are also crucial. At present, plastic packaging accounts for more than 95% of the entire packaging material, among which epoxy packaging materials are among the best with excellent comprehensive performance and special curing methods. They are the most widely used in plastic packaging, accounting for about 90%.

[0003] In recent years, with the rapid development of packaging technology, the performance requirements for packaging materials have been continuously improved. However, most of the existing packaging materials on the market have the following problems and are difficult to meet current needs.

[0004] First, the existing packaging materials have low conversion rates and poor reactivity (or weak cross-linking activity). During the packaging process, this will make it difficult for the material to fully cure, resulting in more residual monomers, which in turn affects the packaging effect and product performance. At the same time, lower reactivity will also prolong the curing time and reduce production efficiency;

[0005] Second, the heat resistance and stability are insufficient. In some specific application scenarios, such as electronic equipment packaging in high temperature environments, the material needs to have good heat resistance to ensure the reliability of the packaging. However, existing packaging materials are prone to deformation and softening at high temperatures, which reduces the protective effect of the packaging.

[0006] The third is poor reliability. This makes the packaging material susceptible to moisture in the atmosphere, resulting in a significant decrease in packaging performance. Moisture intrusion may cause corrosion and short circuits of electronic components, seriously affecting the normal operation of the equipment. In addition, under certain temperature storage, ordinary packaging materials will undergo significant changes, and may even cause damage to display devices and reduce their lifespan. In harsh environments, it is also difficult for ordinary packaging materials to maintain a long-term packaging protection effect.

[0007] Taking China's public patent CN115058147A as an example, the UV-curable monomer used has high surface tension and viscosity at 25°C, which will affect the coating performance and curing effect of the material. At the same time, the organic film formed after photocuring has a low transmittance of 400nm to 780nm wavelengths, which will be limited in some applications that require optical properties. In addition, the optical properties, mechanical properties, thermal properties and reliability of the material have not been studied, which brings uncertainty to practical applications.

[0008] In summary, the disadvantages of current packaging materials can no longer meet the needs of current customers. In order to make up for the above defects, improve the packaging effect of materials, meet the stringent reliability requirements and comprehensive requirements such as chemical resistance, weather resistance, resistance to cold and hot shocks, and extremely low water absorption, it is urgent to develop a packaging material with high reliability and low moisture permeability.

[0009] In view of this, this invention is proposed. Summary of the invention

[0010] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and to provide a high-reliability, low-moisture-permeability UV-curable epoxy packaging ink and its preparation method and application, which are mainly used to solve the many problems of existing packaging materials during use, such as low conversion rate, weak cross-linking activity, insufficient heat resistance and stability, and poor reliability.

[0011] In order to achieve the above object, the present invention adopts the following technical solutions:

[0012] In a first aspect, the present invention provides a high-reliability, low-permeability UV-curable epoxy encapsulation ink, wherein the UV-curable epoxy encapsulation ink comprises the following raw materials in parts by weight: 40 to 60 parts of epoxy silane monomer, 3 to 8 parts of epoxy oligomer resin, 5 to 15 parts of alicyclic epoxy monomer, 10 to 20 parts of diluent, 0 to 0.5 parts of curing accelerator, 1 to 5 parts of photoacid generator and 0.5 to 3 parts of photosensitizer; preferably, the UV-curable epoxy encapsulation ink comprises the following raw materials in parts by weight: 50 to 60 parts of epoxy silane monomer, 3 to 8 parts of epoxy oligomer resin, 5 to 15 parts of alicyclic epoxy monomer, 10 to 20 parts of diluent, 0 to 0.5 parts of curing accelerator, 1 to 5 parts of photoacid generator and 0.5 to 3 parts of photosensitizer. 1-2 parts of epoxy silane monomer, 4-6 parts of epoxy oligomer resin, 10-15 parts of alicyclic epoxy monomer, 15-18 parts of diluent, 0.2-0.3 parts of curing accelerator, 2-4 parts of photoacid generator and 1-2 parts of photosensitizer, that is, the weight ratio of epoxy silane monomer, epoxy oligomer resin, alicyclic epoxy monomer, diluent, curing accelerator, photoacid generator and photosensitizer is (40-60): (3-8): (5-15): (10-20): (0-0.5): (1-5): (0.5-3);

[0013] Wherein, the epoxy silane monomer is an epoxy silane coupling agent.

[0014] Further, the epoxy silane monomer includes one or more of epoxycyclohexylethyltrimethoxysilane (CAS: 3388-04-3), 3-glycidyloxypropyltriethoxysilane (CAS: 2602-34-8), epoxycyclohexylethyltriethoxysilane (CAS: 10217-34-2), 3-glycidylpropoxytrimethoxysilane (CAS: 2530-83-8) or 3-glycidyloxypropylmethyldiethoxysilane (CAS: 2897-60-1).

[0015] The present invention specifically selects a monofunctional epoxy silane coupling agent as the main material. This is because the monofunctional monomers have less steric hindrance, and most of the monomers can actively participate in the cross-linking reaction during the curing reaction. In this way, the system structure will not have the problem of poor curing conversion rate due to steric hindrance, so that the molecular weight distribution of the polymer generated by the reaction is extremely uniform, and there are very few residual monomers, thereby showing an extremely high conversion rate and excellent stability of the film after curing.

[0016] In addition, the cross-linking system is dense and can fully combine with the substrate to form a good interface, thereby obtaining excellent adhesion. This provides strong support for the later high temperature and high humidity reliability verification, fully demonstrating high heat resistance, high chemical corrosion resistance and other properties. More importantly, the siloxane at the end of the chain segment can undergo a hydrolysis reaction with moisture in the air, building a dense cross-linked network structure on the surface of the material film, effectively blocking water and oxygen penetration, and exerting extremely low water absorption and extremely high insulation protection.

[0017] At the same time, the silane molecules at the end of the chain segment will migrate to the surface of the film layer and form covalent bonds with the inorganic materials in the substrate, with strong bonding force and excellent adhesion. It can form a strong bonding point with the ITO surface or SINx surface, thus eliminating the problem of peeling after storage in a high temperature and high humidity environment. In addition, the silanol groups on each silanol molecule can condense with each other to form Si-O-Si bonds, and the silane groups and the functional groups in the silane molecules can form complex chemical bonds with the functional groups in the coating, building a tight interpenetrating network structure, which greatly improves the overall performance of the film and provides excellent reliability and stability.

[0018] Further, the epoxy oligomer resin includes bisphenol A epoxy resin or bisphenol F epoxy resin;

[0019] Wherein, the bisphenol A type epoxy resin includes any one of 2,2-bis[4-(oxyglycidyl)phenyl]propane (CAS: 1675-54-3) and 2,2-bis(4-hydroxycyclohexyl)propane (CAS: 80-04-6);

[0020] The bisphenol F type epoxy resin includes any one of bis[4-(oxyglycidyl)phenyl]methane (CAS: 2095-03-6) and 2-biphenyl glycidyl ether (CAS: 7144-65-2).

[0021] The epoxy oligomer resin used in the present invention has the following advantages: first, it exhibits excellent surface rigidity and excellent scratch resistance, and can provide extremely high packaging protection for the packaged object; second, epoxy resin itself, as an excellent insulating material, has significant advantages in the field of electronic component packaging, and can effectively prevent problems such as short circuits between electronic components to ensure their normal operation. In addition, the epoxy oligomer resin also meets high heat resistance. In the special packaging back-binding process, it can adapt to high temperature environments, ensure the stability and reliability of the packaging, and provide a strong guarantee for the use of electronic components in various complex environments.

[0022] Further, the alicyclic epoxy monomer includes one or more of 3,4-epoxycyclohexylcarboxylic acid-3',4'-epoxycyclohexyl methyl ester (CAS: 2386-87-0), bis((3,4-epoxycyclohexyl)methyl)adipate (CAS: 3130-19-6), dicyclopentadiene diepoxide (CAS: 81-21-0), (3,4,3',4'-diepoxy)dicyclohexane (CAS: 37777-16-5), 3,4-epoxycyclohexanecarboxylic acid methyl ester (CAS: 41088-52-2), 3,4-epoxycyclohexyl methyl methacrylate (CAS: 82428-30-6) or 1,4-cyclohexanedimethanol diglycidyl ether (CAS: 14228-73-0). The molecular weight (MW) of the above substances is between 150 and 400, and in practical use, the molecular weight is preferably between 160 and 370.

[0023] As a functional alicyclic epoxy monomer, it is of great significance to select an alicyclic epoxy monomer with an appropriate molecular weight in the present invention. On the one hand, this monomer can provide a certain degree of flexibility for the material and meet the requirements of high active conversion rate; on the other hand, the molecular structure of the alicyclic epoxy monomer does not contain a benzene ring, which makes it have good weather resistance and anti-ultraviolet aging performance. After curing, it can effectively reduce the yellowing problem of the material and ensure that the material maintains a good appearance and performance during long-term use. This is particularly important for application scenarios that need to be used outdoors or exposed to light for a long time, and provides reliable performance guarantee for the wide application of the material.

[0024] The diluent includes alkyl glycidyl ether or oxetane;

[0025] Wherein, the alkyl glycidyl ether includes any one of octyl glycidyl ether, C12-14 alkyl glycidyl ether, dodecyl glycidyl ether, octadecyl glycidyl ether, glycidyl tert-butyl ether and phenyl glycidyl ether;

[0026] The oxetane includes any one of 3-ethyl-3-oxetanol, 3-ethyl-3-phenylmethoxymethyl-oxetane and 3,3-bis(chloromethyl)oxetane.

[0027] The UV-curable epoxy inkjet ink provided by the present invention cleverly introduces the above-mentioned low-viscosity diluents. These diluents are integrated into the material system during the cross-linking polymerization process, providing it with flexible segments, thereby effectively solving the problem that the film is relatively hard and brittle. Under high-temperature baking conditions, the peeling phenomenon caused by the brittle film can be eliminated. At the same time, the flexible bending performance of the material is also met, so that the ink can adapt to different use conditions and processing requirements in practical applications, laying a solid foundation for its wide application in the fields of electronic packaging and the like.

[0028] Further, the curing accelerator includes an anhydride catalyst or an amine catalyst;

[0029] Wherein, the acid anhydride catalyst includes any one of methyltetrahydrophthalic anhydride, methylnadic anhydride, acetic anhydride, propionic anhydride, butyric anhydride, succinic anhydride, maleic anhydride and phthalic anhydride;

[0030] The amine catalyst includes any one of 2,4,6-tris(dimethylaminomethyl)phenol, benzyldimethylamine, N,N-dimethylcyclohexylamine, bis(2-dimethylaminoethyl)ether, N,N,N',N'-tetramethylalkylenediamine, triethylamine, N,N-dimethylbenzylamine, triethanolamine and N,N'-dimethylpyridine.

[0031] It should be noted that the present invention may also choose not to add a curing accelerator. In this case, only UV light curing is used. If a curing accelerator is added, a light-heat dual curing method can be adopted. During the UV curing process, a portion of heat can be generated, or under certain heating and baking conditions, the reaction activity can be significantly improved. In this way, a very high conversion rate can be achieved in a relatively short period of time, and the cross-linking reaction between monomers can be promoted, thereby effectively shortening the time required for curing. This feature makes the ultraviolet light-curing epoxy encapsulation ink of the present invention have higher efficiency and flexibility in actual production applications, and can meet the needs of different production processes and time requirements.

[0032] Further, the photoacid generator is a cationic photoinitiator, and the cationic photoinitiator includes one or more of triphenyl hexafluorophosphate sulfonium salt, triphenyl tetrakis (pentafluorophenyl) borate sulfonium salt, triaryl hexafluoroantimonate sulfonium salt, triphenyl hexafluoroantimonate sulfonium salt, triphenyl hexafluoroarsenate sulfonium salt, triphenyl tetrafluoroborate sulfonium salt, 4-methylphenyl diphenyl hexafluorophosphate sulfonium salt, 4-(phenylthio) phenyl hexafluorophosphate sulfonium salt, diphenyl hexafluoroantimonate iodonium salt, diphenyl hexafluorophosphate iodonium salt, diphenyl hexafluoroarsenate iodonium salt, diphenyl tetrafluoroborate iodonium salt, ditolyl hexafluoroarsenate iodonium salt or di-tert-butylphenyl hexafluorophosphate iodonium salt.

[0033] Furthermore, the photosensitizer is a hydrogen abstraction type photoinitiator, and the hydrogen abstraction type photoinitiator includes one or more of 2-isopropylthioxanthone, 2,4-diethylthiazolone, 9,10-dibutoxyanthracene, benzophenone, ethyl 4-dimethylaminobenzoate or isopropylthioxanthone.

[0034] The present invention uses a photoacid generator with high activity as an initiator, and is matched with a photosensitizer with mid-band absorption. In the wavelength range of 360nm to 395nm, both have strong absorption capacity, which greatly solves the problem of weak conversion rate of epoxy system. In the case of only ultraviolet light curing, the conversion rate can also be greater than 90%. Moreover, it only needs to be placed at room temperature or a very short heating time to fully meet the conversion rate of more than 97%, which greatly reduces the residual stress of the system, and also meets the extremely low outgas content, providing excellent packaging effects for electronic components.

[0035] In a second aspect, the present invention provides a method for preparing the above-mentioned UV-curing epoxy encapsulation ink, comprising mixing, stirring, filtering and testing 40 to 60 parts of epoxy silane monomer, 3 to 8 parts of epoxy oligomer resin, 5 to 15 parts of alicyclic epoxy monomer, 10 to 20 parts of diluent, 0 to 0.5 parts of curing accelerator, 1 to 5 parts of photoacid generator and 0.5 to 3 parts of photosensitizer at room temperature and in a light-proof environment, to obtain the UV-curing epoxy encapsulation ink after the test is qualified.

[0036] Among them, in order to ensure that the print head will not be affected during inkjet printing, a 0.22μm filter membrane can be used for filtration. The filtered ink is then tested for physical indicators such as viscosity, surface tension, appearance and other indicators.

[0037] In a third aspect, the present invention further provides a use of the above-mentioned UV-curable epoxy encapsulation ink in an organic light-emitting diode, an organic solar cell, a perovskite solar cell or an integrated circuit board encapsulation protective layer.

[0038] Specifically, the encapsulation protection layer includes inorganic layers and organic layers that are alternately arranged in sequence, and the outermost layer is an inorganic layer. The organic layer is made by curing the UV-curable epoxy encapsulation ink through light irradiation; the thickness of the inorganic layer is 5nm to 500nm; the thickness of the organic layer is 0.1μm to 100μm.

[0039] In addition, the UV-curable epoxy encapsulation ink provided by the present invention can be printed on ITO glass or SiNx according to the set size by an IJP inkjet printer. During the printing process, the single-point diffusion of ink droplets, ink droplet speed and ink droplet size, as well as the edge linearity and film thickness uniformity after film formation can be observed; then UV curing is carried out, that is, cross-linking and curing can be carried out to form a dense coating film with a thickness of 5μm to 50μm; then a series of subsequent performance test characterizations are carried out, covering optical properties, conversion rate, mechanical properties, thermal properties, curing shrinkage, water vapor permeability, reliability RA verification, etc. Only when all indicators are qualified, can the UV-curable epoxy inkjet ink with high reliability and low water absorption meet the requirements.

[0040] During the curing process, LED curing lamps are used for curing, with a dry film thickness of 5μm to 50μm, and curing conditions: 365 to 395nm / UV1000 to 1500mj, and heating at 60℃ to 80℃ for 0 to 30min. When a 365nm LED lamp is used for curing, the maximum absorption wavelength range of the photoacid generator is met, the initiation activity is the highest, and no curing accelerator is required; when a 395nm LED lamp is used for curing, depending on the specific application, there is a dark area at a higher thickness, and heating can quickly increase the reaction rate, and a curing accelerator can be appropriately added to increase the curing rate.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1. The UV-curable epoxy encapsulation ink provided by the present invention is mainly composed of epoxy silane monomer, epoxy oligomer resin, alicyclic epoxy monomer, diluent, curing accelerator, photoacid generator and photosensitizer in a specific weight ratio. Among them, the use of epoxy silane coupling agent as the main material has the following many significant advantages: during the curing reaction, most of the epoxy silane coupling agent can actively participate in the cross-linking reaction, fully demonstrating an extremely high conversion rate and excellent stability of the film after curing; in addition, the cross-linking system is tight and dense, and can be fully combined with the substrate to obtain excellent adhesion, which provides strong support for the subsequent high temperature and high humidity reliability verification, and fully reflects the excellent performance of high heat resistance, high chemical corrosion resistance, etc.; at the same time, the material can effectively block the penetration of water and oxygen, exert extremely low water absorption and extremely high insulation protection effect, and eliminate the problem of peeling after high temperature and high humidity storage. Moreover, the interaction of the above components greatly improves the comprehensive performance of the film, providing excellent reliability and stability for the packaging of electronic components.

[0043] 2. The UV-curable epoxy encapsulation ink provided by the present invention introduces oligomer epoxy resin, which has excellent surface rigidity and scratch resistance, and can provide high encapsulation protection for the encapsulated object. At the same time, the ink meets high heat resistance and can adapt to high temperature environments in special encapsulation back-binding processes. In addition, alicyclic epoxy monomers with appropriate molecular weight (160-370) are introduced. This monomer not only provides a certain flexibility for the material, but also meets the high activity conversion rate requirements, and has good weather resistance and UV aging resistance, and can effectively reduce the yellowing problem of the material after curing.

[0044] 3. The UV-curable epoxy encapsulation ink provided by the present invention introduces a low-viscosity diluent, which is cross-linked and polymerized into the material system to provide a flexible segment, successfully solving the problem of the film being hard and brittle. Under high-temperature baking, the peeling phenomenon caused by the brittle film can be eliminated, while meeting the flexible bending performance. In addition, a small amount of curing accelerator can be introduced to generate some heat during UV curing, or to increase the reaction activity under certain heating and baking conditions, thereby achieving a high conversion rate in a shorter time, promoting the cross-linking reaction between monomers, and shortening the time required for curing.

[0045] 4. The UV-curable epoxy packaging ink provided by the present invention uses a highly active photoacid generator as an initiator and is matched with a photosensitizer that absorbs in the mid-wave band. It has strong absorption in the wavelength range of 360nm to 395nm, which greatly solves the problem of weak conversion rate of the epoxy system. It can also meet the conversion rate of >90% under UV curing alone, and only needs to be placed at room temperature or a very short heating time to fully meet the conversion rate of >97%, which greatly reduces the residual stress of the system and meets the extremely low outgas content (liquid outgas is 150ppm to 200ppm; film outgas is 20ppm to 50ppm), providing excellent packaging effects for electronic components. DETAILED DESCRIPTION

[0046] Here, exemplary embodiments will be described in detail, and the embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are only examples consistent with some aspects of the present invention described in detail in the appended claims.

[0047] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with relevant experiments.

[0048] Example 1

[0049] An embodiment of the present invention provides a high-reliability, low-moisture-permeability UV-curable epoxy encapsulation ink, whose raw materials, by weight, include 40 parts of epoxy silane monomer, 4 parts of epoxy oligomer resin, 5 parts of alicyclic epoxy monomer, 15 parts of diluent, 0.1 parts of curing accelerator, 1 part of photoacid generator and 0.5 parts of photosensitizer.

[0050] Specifically, the epoxy silane monomer is epoxycyclohexylethyltrimethoxysilane (CAS: 3388-04-3).

[0051] The epoxy oligomer resin is 2,2-bis[4-(oxyglycidyl)phenyl]propane (CAS: 1675-54-3).

[0052] The alicyclic epoxy monomer is 3,4-epoxycyclohexylcarboxylic acid-3',4'-epoxycyclohexylmethyl ester (CAS: 2386-87-0), MW (molecular weight): 252.31.

[0053] Octyl glycidyl ether was selected as the diluent.

[0054] Methyltetrahydrophthalic anhydride is selected as the curing accelerator.

[0055] The photoacid generator is triphenylsulfonium hexafluorophosphate.

[0056] The photosensitizer is 2,4-diethylthiazolone.

[0057] When preparing the ultraviolet light curing epoxy encapsulation ink, 40 parts of epoxycyclohexylethyltrimethoxysilane (CAS: 3388-04-3), 4 parts of 2,2-bis[4-(oxyglycidyl)phenyl]propane (CAS: 1675-54-3), 5 parts of 3,4-epoxycyclohexylcarboxylic acid-3', 4'-epoxycyclohexylmethyl ester (CAS: 2386-87-0), 15 parts of octyl glycidyl ether, 0.1 parts of methyltetrahydrophthalic anhydride, 1 part of triphenyl hexafluorophosphate sulfonium salt and 0.5 parts of 2,4-diethylthiazolone are mixed and stirred at room temperature and protected from light. The ink is a clear and transparent liquid. In order to ensure that the print head will not be affected during inkjet printing, a 0.22 μm filter membrane is used for suction filtration. The filtered ink is tested by physical indicators to obtain a finished ink product.

[0058] The specific process of forming a cured coating using the UV-curable epoxy encapsulation ink prepared in this embodiment is as follows:

[0059] 1) using an IJP inkjet printer to attach the ink to the surface of the electronic device to be packaged;

[0060] 2) Use LED lamp to cure the surface after inkjet printing. Specifically, irradiate with UV 1000mj in the wavelength range of 360nm to 395nm (in this range, LED lamp can provide efficient ultraviolet light energy), control the temperature at 80℃, and continue curing for 10min to promote the chemical reaction of each component in the ink, achieve rapid curing, and finally form a cured coating with a dry film thickness of 15μm.

[0061] Example 2

[0062] An embodiment of the present invention provides a high-reliability, low-moisture-permeability UV-curable epoxy encapsulation ink, whose raw materials, by weight, include 50 parts of epoxy silane monomer, 6 parts of epoxy oligomer resin, 5 parts of alicyclic epoxy monomer, 10 parts of diluent, 0.2 parts of curing accelerator, 2 parts of photoacid generator and 1 part of photosensitizer.

[0063] Specifically, the epoxy silane monomer is 3-glycidyloxypropyltriethoxysilane (CAS: 2602-34-8).

[0064] The epoxy oligomer resin is bis[4-(oxyglycidyl)phenyl]methane (CAS: 2095-03-6).

[0065] The alicyclic epoxy monomer is 3,4-epoxycyclohexylcarboxylic acid-3',4'-epoxycyclohexylmethyl ester (CAS: 2386-87-0), MW (molecular weight): 252.31.

[0066] The diluent is C12-14 alkyl glycidyl ether.

[0067] Methyltetrahydrophthalic anhydride is selected as the curing accelerator.

[0068] The photoacid generator is triphenylsulfonium hexafluorophosphate.

[0069] The photosensitizer is 9,10-dibutoxyanthracene.

[0070] When preparing the ultraviolet light curing epoxy encapsulation ink, 50 parts of 3-glycidyloxypropyltriethoxysilane (CAS: 2602-34-8), 6 parts of bis[4-(oxyglycidyl)phenyl]methane (CAS: 2095-03-6), 5 parts of 3,4-epoxycyclohexylcarboxylic acid-3',4'-epoxycyclohexylmethyl ester (CAS: 2386-87-0), 10 parts of C12-14 alkyl glycidyl ether, 0.2 parts of methyltetrahydrophthalic anhydride, 2 parts of triphenyl hexafluorophosphate sulfonium salt and 1 part of 9,10-dibutoxyanthracene are mixed and stirred at room temperature and protected from light. The ink is a clear and transparent liquid. In order to ensure that the print head will not be affected during inkjet printing, a 0.22 μm filter membrane is used for suction filtration. The filtered ink is tested by physical indicators to obtain a finished ink product.

[0071] The specific process of forming a cured coating using the UV-curable epoxy encapsulation ink prepared in this embodiment is as follows:

[0072] 1) using an IJP inkjet printer to attach the ink to the surface of the electronic device to be packaged;

[0073] 2) Use LED lamp to cure the surface after inkjet printing. Specifically, irradiate with UV 1300mj in the wavelength range of 360nm to 395nm (in this range, LED lamp can provide efficient ultraviolet light energy), control the temperature at 70℃, and continue curing for 20min to promote the chemical reaction of each component in the ink, achieve rapid curing, and finally form a cured coating with a dry film thickness of 15μm.

[0074] Example 3

[0075] An embodiment of the present invention provides a high-reliability, low-moisture-permeability UV-curable epoxy encapsulation ink, whose raw materials, by weight, include 50 parts of epoxy silane monomer, 6 parts of epoxy oligomer resin, 10 parts of alicyclic epoxy monomer, 18 parts of diluent, 0.3 parts of curing accelerator, 5 parts of photoacid generator and 3 parts of photosensitizer.

[0076] Specifically, the epoxysilane monomer is epoxycyclohexylethyltriethoxysilane (CAS: 10217-34-2).

[0077] The epoxy oligomer resin is 2-biphenyl glycidyl ether (CAS: 7144-65-2).

[0078] The alicyclic epoxy monomer is bis((3,4-epoxycyclohexyl)methyl)adipate (CAS: 3130-19-6), MW (molecular weight): 366.45.

[0079] The diluent is phenyl glycidyl ether.

[0080] The curing accelerator is methyl nadic anhydride.

[0081] The photoacid generator is triphenyltetrakis(pentafluorobenzene)borate sulfonium salt.

[0082] The photosensitizer is benzophenone.

[0083] When preparing the ultraviolet light curing epoxy encapsulation ink, 50 parts of epoxycyclohexylethyltriethoxysilane (CAS: 10217-34-2), 6 parts of 2-biphenyl glycidyl ether (CAS: 7144-65-2), 10 parts of bis((3,4-epoxycyclohexyl)methyl)adipate (CAS: 3130-19-6), 18 parts of phenyl glycidyl ether, 0.3 parts of methyl nadic anhydride, 5 parts of triphenyltetrakis(pentafluorophenyl)borate sulfonium salt and 3 parts of benzophenone are mixed and stirred at room temperature and in a light-proof environment. The ink is a clear and transparent liquid. In order to ensure that the print head will not be affected during inkjet printing, a 0.22 μm filter membrane is required for suction filtration. The filtered ink is tested by physical indicators to obtain a finished ink product.

[0084] The specific process of forming a cured coating using the UV-curable epoxy encapsulation ink prepared in this embodiment is as follows:

[0085] 1) using an IJP inkjet printer to attach the ink to the surface of the electronic device to be packaged;

[0086] 2) Use LED lamp to cure the surface after inkjet printing. Specifically, irradiate with UV 1400mj in the wavelength range of 360nm to 395nm (in this range, LED lamp can provide efficient ultraviolet light energy), control the temperature at 65℃, and continue curing for 15min to promote the chemical reaction of each component in the ink, achieve rapid curing, and finally form a cured coating with a dry film thickness of 20μm.

[0087] Example 4

[0088] An embodiment of the present invention provides a high-reliability, low-moisture-permeability UV-curable epoxy encapsulation ink, whose raw materials, by weight, include 60 parts of epoxy silane monomer, 8 parts of epoxy oligomer resin, 15 parts of alicyclic epoxy monomer, 20 parts of diluent, 0.1 parts of curing accelerator, 1 part of photoacid generator and 2 parts of photosensitizer.

[0089] Specifically, the epoxy silane monomer is 3-glycidyl propoxy trimethoxy silane (CAS: 2530-83-8).

[0090] The epoxy oligomer resin is 2,2-bis(4-hydroxycyclohexyl)propane (CAS: 80-04-6).

[0091] The alicyclic epoxy monomer is dicyclopentadiene diepoxide (CAS: 81-21-0), MW (molecular weight): 164.2.

[0092] The diluent is 3-ethyl-3-oxetanol.

[0093] The curing accelerator is 2,4,6-tris(dimethylaminomethyl)phenol.

[0094] The photoacid generator is triarylsulfonium hexafluoroantimonate.

[0095] The photosensitizer is ethyl 4-dimethylaminobenzoate.

[0096] When preparing the ultraviolet light curing epoxy encapsulation ink, 60 parts of 3-glycidyl propoxy trimethoxy silane (CAS: 2530-83-8), 8 parts of 2,2-bis (4-hydroxycyclohexyl) propane (CAS: 80-04-6), 15 parts of dicyclopentadiene diepoxide (CAS: 81-21-0), 20 parts of 3-ethyl-3-oxetane methanol, 0.1 parts of 2,4,6-tris (dimethylaminomethyl) phenol, 1 part of triaryl hexafluoroantimonate sulfonium salt and 2 parts of ethyl 4-dimethylaminobenzoate are mixed and stirred at room temperature and protected from light. The ink is a clear and transparent liquid. In order to ensure that the print head will not be affected during inkjet printing, a 0.22 μm filter membrane is used for suction filtration. The filtered ink is tested by physical indicators to obtain a finished ink product.

[0097] The specific process of forming a cured coating using the UV-curable epoxy encapsulation ink prepared in this embodiment is as follows:

[0098] 1) using an IJP inkjet printer to attach the ink to the surface of the electronic device to be packaged;

[0099] 2) Use LED lamp to cure the surface after inkjet printing. Specifically, irradiate with UV 1100mj in the wavelength range of 360nm to 395nm (in this range, LED lamp can provide efficient ultraviolet light energy), control the temperature at 60℃, and continue curing for 30min to promote the chemical reaction of each component in the ink, achieve rapid curing, and finally form a cured coating with a dry film thickness of 35μm.

[0100] Example 5

[0101] An embodiment of the present invention provides a high-reliability, low-moisture-permeability UV-curable epoxy encapsulation ink, whose raw materials, by weight, include 40 parts of epoxy silane monomer, 6 parts of epoxy oligomer resin, 15 parts of alicyclic epoxy monomer, 10 parts of diluent, 4 parts of photoacid generator and 2 parts of photosensitizer.

[0102] Specifically, the epoxy silane monomer is 3-glycidyloxypropylmethyldiethoxysilane (CAS: 2897-60-1).

[0103] The epoxy oligomer resin is 2,2-bis[4-(oxyglycidyl)phenyl]propane (CAS: 1675-54-3).

[0104] The alicyclic epoxy monomer is 3,4-epoxycyclohexylcarboxylic acid-3',4'-epoxycyclohexylmethyl ester (CAS: 2386-87-0), MW (molecular weight): 252.31.

[0105] The diluent is 3-ethyl-3-phenylmethoxymethyl-oxetane.

[0106] No curing accelerator is added.

[0107] The photoacid generator is triphenylsulfonium hexafluorophosphate.

[0108] The photosensitizer used was 2-isopropylthioxanthone.

[0109] When preparing the ultraviolet light curing epoxy encapsulation ink, 40 parts of 3-glycidyloxypropylmethyldiethoxysilane (CAS: 2897-60-1), 6 parts of 2,2-bis[4-(oxyglycidyl)phenyl]propane (CAS: 1675-54-3), 15 parts of 3,4-epoxycyclohexylcarboxylic acid-3',4'-epoxycyclohexylmethyl ester (CAS: 2386-87-0), 10 parts of 3-ethyl-3-phenylmethoxymethyl-oxetane, 4 parts of triphenylsulfonium hexafluorophosphate and 2 parts of 2-isopropylthioxanthone are mixed and stirred at room temperature and protected from light. The ink is a clear and transparent liquid. In order to ensure that the print head will not be affected during inkjet printing, a 0.22 μm filter membrane is used for suction filtration. The filtered ink is tested by physical indicators to obtain a finished ink product.

[0110] The specific process of forming a cured coating using the UV-curable epoxy encapsulation ink prepared in this embodiment is as follows:

[0111] 1) using an IJP inkjet printer to attach the ink to the surface of the electronic device to be packaged;

[0112] 2) Use LED lamp to cure the surface after inkjet printing. Specifically, irradiate with UV 1500mj in the wavelength range of 360nm to 395nm (in this range, LED lamp can provide efficient ultraviolet light energy), control the temperature at 60℃, and continue curing for 28min to promote the chemical reaction of each component in the ink, achieve rapid curing, and finally form a cured coating with a dry film thickness of 50μm.

[0113] Comparative Example 1

[0114] The only difference between this comparative example and Example 1 is that 40 parts of epoxy silane monomers are replaced by 40 parts of bisphenol A glycidyl ether.

[0115] Comparative Example 2

[0116] The only difference between this comparative example and Example 1 is that the amount of epoxy silane monomer added is 70 parts, that is, the amount of epoxy silane monomer added is too much.

[0117] Comparative Example 3

[0118] The only difference between this comparative example and Example 1 is that the amount of epoxy silane monomer added is 20 parts, that is, the amount of epoxy silane monomer added is too little.

[0119] Comparative Example 4

[0120] The only difference between this comparative example and Example 1 is that the alicyclic epoxy monomer is replaced by glycerol triglycidyl ether.

[0121] In order to verify the efficacy of the present invention, the applicant tested the inks prepared in Examples 1 to 5 and Comparative Examples 1 to 4 and the cured films formed therefrom. The test items included tests on ink properties, other properties, optical properties, mechanical properties, thermal properties, reliability, etc., as shown in Table 1 below:

[0122] Table 1 Test item introduction

[0123]

[0124]

[0125] It should be noted that the conversion rate of the present invention is tested by the gel rate method. The cured film is weighed and recorded as m1, then immersed in a PMA solution at 60°C for 24 hours, and then taken out and dried at 80°C for 1 hour and weighed as m2. The gel rate = m2 / m1*100%. Continue to soak and weigh according to the above steps until the gel rate is constant, which is the conversion rate.

[0126] The transmittance of this application refers to the transmittance at a wavelength of 380nm~400nm. The existing tests generally have a wavelength of 400nm~700nm, and the test data is the average value of the total band. The test requirements are relatively low, while the requirements of this application are relatively high. As long as the transmittance in the 380nm~400nm band meets the standard, then the transmittance in the 400nm~700nm band will definitely meet the standard.

[0127] The specific results after testing are shown in Table 2 below:

[0128] Table 2 Test results

[0129]

[0130]

[0131] The test results in Table 2 are analyzed as follows:

[0132] It can be seen from the test results of Examples 1 to 5 and Comparative Examples 1 to 4 that the inks using the formula of the present invention are all clear and transparent in appearance, and have suitable viscosity and surface tension. At the same time, it exhibits excellent conversion rate and water vapor permeability, and the optical performance is better than that of the comparative example. In addition, compared with the comparative example, the present embodiment performs excellently in mechanical properties and thermal properties. From the perspective of reliability, the film of the present embodiment has no optical or appearance changes in all aspects, while the comparative example has wrinkling, discoloration or shedding to varying degrees. Specifically, when the amount of epoxy silane monomer added is too much, uneven film thickness, low viscosity and surface tension, and abnormal printing will occur, resulting in reduced reliability; and when the amount of epoxy silane monomer added is too little, the water vapor permeability will be too high, which will eventually lead to reduced adhesion, and then wrinkling, shedding, discoloration and other phenomena to varying degrees will occur, which will also reduce reliability.

[0133] In summary, the present invention selects an epoxy packaging material system to address the many problems of current packaging materials during use, such as weak cross-linking activity, low conversion rate, high water and oxygen permeability, and poor reliability. By introducing a monofunctional epoxy silane monomer with strong cross-linking activity as the main body of the formula, the problem of poor curing conversion rate and a large number of residual monomers due to steric hindrance in the system structure is effectively avoided; secondly, the polymer generated after the curing reaction is evenly distributed and the cross-linking system is dense, thereby obtaining a strong material cohesion, and excelling in reliability verification performance such as high temperature and humidity resistance, chemical resistance, and heat resistance, and can meet the current stringent packaging requirements; at the same time, the silane bonds at the ends of the chain segments can also undergo self-cross-linking reactions to form a network-penetrating structure, which provides the material with good adhesion to the substrate and low curing shrinkage, and the silicon-oxygen bonds exposed outside the structure can combine with the inorganic materials in the substrate to form hydrogen bonds, further improving the adhesion to the substrate. More importantly, it can participate in the hydrolysis reaction with trace water molecules in the air, forming a dense cross-linked network structure on the surface of the material film, thereby effectively blocking the penetration of water and oxygen, and playing an extremely low water absorption role and extremely high insulation protection role.

[0134] In addition, in order to make up for the defect that the material may be brittle due to excessive crosslinking, the present invention introduces a low-viscosity flexible diluent. This diluent can not only fully dissolve other epoxy materials as a diluent, but also provide the material with comprehensive performance of both softness and hardness, meeting the packaging requirements of flexible bending. Combined with epoxy resins, alicyclic epoxy monomers and curing accelerators with appropriate molecular weight and special functional properties, the reaction activity is greatly improved, and the material conversion rate is also greatly improved, providing excellent comprehensive performance for the field of electronic packaging.

[0135] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention.

[0136] It should be understood that the present invention is not limited to what has been described above and that various modifications and changes may be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A high reliability and low moisture permeability UV curing epoxy encapsulation ink, characterized in that: The ultraviolet light curing epoxy encapsulation ink comprises the following raw materials by weight: 40 to 60 parts of epoxy silane monomer, 3 to 8 parts of epoxy oligomer resin, 5 to 15 parts of alicyclic epoxy monomer, 10 to 20 parts of diluent, 0 to 0.5 parts of curing accelerator, 1 to 5 parts of photoacid generator and 0.5 to 3 parts of photosensitizer; Wherein, the epoxy silane monomer is an epoxy silane coupling agent.

2. The high reliability and low moisture permeability UV-curable epoxy encapsulation ink according to claim 1, characterized in that: The epoxysilane monomer includes one or more of epoxycyclohexylethyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, epoxycyclohexylethyltriethoxysilane, 3-glycidylpropoxytrimethoxysilane or 3-glycidyloxypropylmethyldiethoxysilane.

3. The high reliability and low moisture permeability UV-curable epoxy encapsulation ink according to claim 1, characterized in that: The epoxy oligomer resin includes any one of 2,2-bis[4-(oxyglycidyl)phenyl]propane, bis[4-(oxyglycidyl)phenyl]methane, 2-biphenyl glycidyl ether, and 2,2-bis(4-hydroxycyclohexyl)propane.

4. The high reliability and low moisture permeability UV-curable epoxy encapsulation ink according to claim 1, characterized in that: The alicyclic epoxy monomer includes one or more of 3,4-epoxycyclohexylcarboxylic acid-3',4'-epoxycyclohexyl methyl ester, bis((3,4-epoxycyclohexyl)methyl)adipate, dicyclopentadiene diepoxide, (3,4,3',4'-diepoxy)bicyclohexane, 3,4-epoxycyclohexanecarboxylic acid methyl ester, 3,4-epoxycyclohexyl methyl methacrylate or 1,4-cyclohexanedimethanol diglycidyl ether.

5. The high reliability and low moisture permeability UV-curable epoxy encapsulation ink according to claim 1, characterized in that: The diluent includes alkyl glycidyl ether or oxetane; Wherein, the alkyl glycidyl ether includes any one of octyl glycidyl ether, C12-14 alkyl glycidyl ether, dodecyl glycidyl ether, octadecyl glycidyl ether, glycidyl tert-butyl ether and phenyl glycidyl ether; The oxetane includes any one of 3-ethyl-3-oxetanol, 3-ethyl-3-phenylmethoxymethyl-oxetane and 3,3-bis(chloromethyl)oxetane.

6. The high reliability and low moisture permeability UV curing epoxy encapsulation ink according to claim 1, characterized in that: The curing accelerator includes an anhydride catalyst or an amine catalyst; Wherein, the acid anhydride catalyst includes any one of methyltetrahydrophthalic anhydride, methylnadic anhydride, acetic anhydride, propionic anhydride, butyric anhydride, succinic anhydride, maleic anhydride and phthalic anhydride; The amine catalyst includes any one of 2,4,6-tris(dimethylaminomethyl)phenol, benzyldimethylamine, N,N-dimethylcyclohexylamine, bis(2-dimethylaminoethyl)ether, N,N,N',N'-tetramethylalkylenediamine, triethylamine, N,N-dimethylbenzylamine, triethanolamine and N,N'-dimethylpyridine.

7. The high reliability and low moisture permeability UV-curable epoxy encapsulation ink according to claim 1, characterized in that: The photoacid generator is a cationic photoinitiator, and the cationic photoinitiator includes one or more of triphenyl hexafluorophosphate sulfonium salt, triphenyl tetrakis (pentafluorophenyl) borate sulfonium salt, triaryl hexafluoroantimonate sulfonium salt, triphenyl hexafluoroantimonate sulfonium salt, triphenyl hexafluoroarsenate sulfonium salt, triphenyl tetrafluoroborate sulfonium salt, 4-methylphenyl diphenyl hexafluorophosphate sulfonium salt, 4-(phenylthio) phenyl hexafluorophosphate sulfonium salt, diphenyl hexafluoroantimonate iodonium salt, diphenyl hexafluorophosphate iodonium salt, diphenyl hexafluoroarsenate iodonium salt, diphenyl tetrafluoroborate iodonium salt, ditolyl hexafluoroarsenate iodonium salt or di-tert-butylphenyl hexafluorophosphate iodonium salt.

8. The high reliability and low moisture permeability UV-curable epoxy encapsulation ink according to claim 1, characterized in that: The photosensitizer is a hydrogen abstraction type photoinitiator, and the hydrogen abstraction type photoinitiator includes one or more of 2-isopropylthioxanthone, 2,4-diethylthiazolone, 9,10-dibutoxyanthracene, benzophenone, ethyl 4-dimethylaminobenzoate or isopropylthioxanthone.

9. A method for preparing a high-reliability, low-moisture-permeability UV-curable epoxy encapsulation ink according to any one of claims 1 to 8, characterized in that: The UV-curable epoxy encapsulation ink is obtained by mixing and stirring 40 to 60 parts of epoxy silane monomer, 3 to 8 parts of epoxy oligomer resin, 5 to 15 parts of alicyclic epoxy monomer, 10 to 20 parts of diluent, 0 to 0.5 parts of curing accelerator, 1 to 5 parts of photoacid generator and 0.5 to 3 parts of photosensitizer, and filtering.

10. A UV-curable epoxy encapsulation ink prepared by the preparation method according to claim 9, or a use of the UV-curable epoxy encapsulation ink according to any one of claims 1 to 8 in an organic light-emitting diode, an organic solar cell, a perovskite solar cell or an integrated circuit board encapsulation protective layer.

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