A uv conductive frame adhesive for flexible bendable substrate bonding and a preparation method thereof

Abstract

The application relates to a UV conductive frame adhesive for bonding a flexible bendable substrate and a preparation method thereof, and the preparation raw materials comprise polyurethane acrylate, mixed acrylic monomers, a photoinitiator, a coupling agent and conductive fillers. The preparation method is as follows: mixing the polyurethane acrylate and the photoinitiator according to a proportion to obtain an active mixed system; adding the mixed acrylic monomers and the coupling agent to obtain an organic active system; adding the conductive fillers into the organic active system, mixing and obtaining conductive UV adhesive; adding 30% zirconium beads for grinding and vacuumizing, and the conductive frame adhesive is obtained. The UV conductive frame adhesive of the application uses mixed acrylic monomers as raw materials, has no ion risk, and specific proportion mixed monomers can adjust performance, adapt to flexible screens, and promote dispersion of conductive fillers; ATO as the filler has good dispersion, good light transmission, strong barrier and high cost performance; on the process, the zirconium beads grind ATO to preserve the crystal form, stabilize the conductive network and inhibit ion migration; the room temperature UV single-step curing has the advantages of free radical polymerization, is free of drying, and meanwhile, the polyurethane acrylate as a skeleton increases the durability.

Description

Technical Field

[0001] This application relates to the field of conductive UV adhesive technology, specifically to a UV conductive frame adhesive for bonding flexible and bendable substrates and its preparation method. Background Technology

[0002] The rapid development of flexible display devices has placed extremely stringent and diverse performance requirements on conductive adhesives. Key indicators include low volume resistivity, high transmittance (>90%), strong adhesion, bending resistance, and stability under damp heat aging. As a core material for interconnecting flexible electronic devices, conductive adhesives work by bonding conductive fillers to a resin matrix, thereby establishing stable conductive paths.

[0003] Currently, the mainstream conductive adhesive systems include epoxy, silicone, and acrylic systems, each with its own characteristics but also significant drawbacks. Epoxy systems have high crosslinking density and strong interfacial adhesion; however, they are brittle after curing, with prominent stress concentration issues, making them unsuitable for the repeated folding requirements of flexible display devices. Silicone systems offer excellent weather resistance and low modulus, but their poor wettability to the substrate leads to a significant increase in interfacial resistance with damp heat cycling, affecting the stability of device performance. Acrylic systems, due to their advantages such as fast free radical polymerization rate, high adhesive strength, wide adjustable glass transition temperature (Tg) range, and high transparency, have become a research hotspot in the field of flexible optical adhesives.

[0004] However, traditional acrylate conductive adhesives often employ thermosetting or dual-curing processes, which have numerous drawbacks. These processes typically require post-baking at 80-120℃, which exacerbates the warping deformation of flexible substrates and introduces thermal stress. Furthermore, their dense cross-linked network leads to a decrease in yield elongation, limiting the material's application in flexible displays. For example, CN112358841A discloses a UV-thermal dual-curing transparent conductive adhesive using a self-made silicone-blocked epoxy acrylate, but it still requires a second curing at 90℃. This not only narrows the process window and worsens storage stability, but the heating curing process also affects device reliability, causing adhesive layer bulging and accelerating phase separation. Therefore, developing an acrylate conductive adhesive that can achieve single-step UV curing at room temperature, possesses low modulus and high elongation, strong interfacial adhesion, and excellent hygrothermal stability has become a key material challenge that the flexible display industry urgently needs to overcome.

[0005] To address the aforementioned issues, modifications to acrylate conductive adhesives were studied. The modified acrylate conductive adhesives achieved room temperature curing. For example, CN115636912B discloses a method for preparing a UV-curable flexible conductive adhesive resin matrix. This method uses hydroxyl-modified styrene copolymers and acrylic acid as the flexible conductive adhesive resin matrix. The fracture stress of the modified material increased from 22 MPa to 32 MPa, significantly improving flexibility and exhibiting low volume resistivity, thus meeting the performance requirements of flexible electronic materials. However, this modified material has the problem of chloromethyl residue, which may lead to migration corrosion risks, while flexible display devices have extremely strict requirements for ion content. Summary of the Invention

[0006] To address the aforementioned issues, this application provides a UV conductive frame adhesive for bonding flexible and bendable substrates and its preparation method. The aim is to overcome the bottlenecks of flexibility, polarity, and weather resistance while retaining the advantages of rapid UV curing, thus adapting to the integration of multi-layer heterogeneous materials in flexible screens and extreme deformation scenarios.

[0007] Firstly, the UV conductive frame adhesive for bonding flexible and bendable substrates provided in this application adopts the following technical solution:

[0008] A UV conductive frame adhesive for bonding flexible and bendable substrates, the raw materials for which are prepared include the following components:

[0009] The composition includes: 30-60% polyurethane acrylate; 20-50% mixed acrylic monomers; 3-6% photoinitiator; 0.5-5% coupling agent; 10-30% conductive filler; wherein the mixed acrylic monomers include monofunctional acrylic monomers and modified trifunctional acrylic monomers, and the mass ratio of the monofunctional acrylic monomers to the modified trifunctional acrylic monomers is 1:2-6; the conductive filler is nano-inorganic metal oxide ATO with a particle size of 5-10 nm.

[0010] By adopting the above technical solution, the prepared UV conductive frame adhesive not only has good conductivity, but also has the advantages of low volume resistivity, multiple bending capability, high transmittance, and high connection strength, and can be widely used in coating various flexible substrates. Adding nanoparticle ATO as a conductive filler to the system can bring many advantages. It can not only enhance the light transmittance of the material and ensure the stability of conductivity, but also effectively reduce the volume resistivity. Moreover, ATO raw material has a low cost, which has significant advantages in terms of economic benefits.

[0011] ATO is produced by doping antimony into the SnO2 lattice, forming oxygen vacancies, which in turn create free electron migration channels. When ATO is mixed with acrylic resin, the hydroxyl groups (-OH) on its surface will form hydrogen bonds with the acrylate groups (-COOCH3), thereby forming a stable dispersion system.

[0012] Meanwhile, ATO exhibits quantum size effect; when its particle size is less than 1 / 20 of the wavelength of visible light, photon diffraction plays a dominant role, significantly reducing light scattering loss. This gives ATO nanoparticles high transmittance. In terms of grinding, the hardness of ATO matches well with that of zirconium beads. During grinding, the breakage rate of ATO particles can be controlled within 15%, effectively avoiding the problem of decreased conductivity due to over-grinding. Furthermore, ATO is not prone to plastic deformation during grinding, maintaining its original crystal structure and ensuring the stability of the conductive network. In addition, since the SnO2 content on the ATO surface exceeds 90%, it can effectively suppress ion migration.

[0013] Further, the monofunctional acrylic monomer includes one or more of the following: β-carboxyethyl acrylate, isobornyl methacrylate, isobornyl acrylate, cyclotrimethylolpropane methyl acetal acrylate, tetrahydrofuran acrylate, isodeyl acrylate, caprolactone acrylate, isooctyl acrylate, stearic acid acrylate, isodeyl methacrylate, stearic acid methacrylate, (ethoxy)phenol acrylate, 2(ethoxy)phenol acrylate, 4(ethoxy)phenol acrylate, 2-phenoxyethyl methacrylate, o-phenylphenoxyethyl acrylate, ethoxyethoxyethyl acrylate, 4(ethoxy)nonylphenol acrylate, tetrahydrofurfuryl acrylate, cyclotrimethylolpropane acetal acrylate, and trimethylolcyclohexyl acrylate.

[0014] Furthermore, the modified trifunctional acrylic monomer is a trifunctional acrylic monomer incorporating -CH2-CH2-O- or -CH2-CH(CH3)-O-, specifically including one or more of 3(ethoxy)trimethylolpropane triacrylate, 6(ethoxy)trimethylolpropane triacrylate, 9(ethoxy)trimethylolpropane triacrylate, 15(ethoxy)trimethylolpropane triacrylate, 20(ethoxy)trimethylolpropane triacrylate, and 3(propoxy)trimethylolpropane triacrylate.

[0015] By adopting the above technical solution, the monofunctional acrylic monomer and the modified trifunctional acrylic monomer are mixed in a specific ratio, which can adjust the performance of the adhesive in many aspects. This mixing method can not only adjust the curing speed, crosslinking density and flexibility of the adhesive, but also effectively adjust its viscosity, which helps the solid conductive filler to be uniformly dispersed in polyurethane acrylate, thereby reducing resistivity and improving the conductivity of the conductive material.

[0016] Specifically, monofunctional acrylic monomers mainly play a role in regulating viscosity in the system. They can enhance the wettability of the adhesive to the substrate, while controlling the rate of crosslinking reaction and preventing stress concentration caused by excessively fast curing. Modified trifunctional acrylic monomers, by introducing ethoxy or propoxy groups, extend the flexibility of the chain segments, alleviate the rigidity of the trifunctional monomers themselves, and avoid embrittlement of the adhesive layer, thereby improving the bending life of the adhesive layer. At the same time, the trifunctionality ensures that a three-dimensional crosslinking network can be formed after curing, so that the conductive filler can be stably suspended in it.

[0017] During the cross-linking and curing process, the contraction force generated between molecules causes the conductive filler filling the spaces between molecules to form a denser conductive channel, thereby improving the conductivity of the conductive adhesive and reducing the volume resistivity. By flexibly adjusting the types and ratios of monofunctional monomers and modified trifunctional monomers, the key properties of the final adhesive layer, such as hardness, modulus, flexibility, curing shrinkage rate, curing speed, and internal stress, can be precisely controlled, so that it can meet the bending requirements of the flexible substrate and provide the structural support required by the frame adhesive.

[0018] Furthermore, the viscosity of the polyurethane acrylate at 25°C is 2000-40000cps, including one or two of the following: Lankel L-8406, Songda SD7832A, SD860, SD867, SD877, Ruiang GENOMER 4316, GENOMER 5271, and Runao FSP5894.

[0019] By adopting the above technical solution, polyurethane acrylate plays a skeleton role in the formulation, laying the foundation for the adhesive's mechanical properties, flexibility and bending durability. The acrylate double bonds it contains have UV curing properties and can form a cross-linked network structure during the curing process.

[0020] Among them, the polyether or polyester soft segments in the polyurethane chain give the adhesive layer good elasticity, which enables the adhesive layer to adapt well to the repeated bending of the flexible substrate, effectively avoiding breakage during bending and preventing the adhesive layer from cracking or delaminating when bending.

[0021] In addition, the polar groups such as ester and urethane groups in polyurethane acrylate can significantly enhance the interfacial bonding force between the adhesive and the substrate, thereby improving the adhesive performance. Moreover, these polar groups also help to improve the impact resistance and crack resistance of the adhesive layer, making the adhesive layer more durable.

[0022] Further, the photoinitiator is one or more of 2-methyl-1-(4-methylthiophenyl)-2-morpholine-1-propanone, 2-hydroxy-2-methylphenylpropanone, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 1-hydroxycyclohexylphenyl ketone, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 2-benzyl-2-dimethylamino-1-(4-morpholinephenyl)butanone, 2,4-diethylthioxanthrone, benzophenone, and bibenzoyl.

[0023] Furthermore, the coupling agent is a silane coupling agent, including one of 3-chloropropyltrichlorosilane, 3-chloropropyltrimethoxysilane, n-octyltrimethoxysilane, dodecyltrimethoxysilane, 3-glycidyl etheroxypropyldiethoxysilane, and 3-methacryloyloxypropylmethyldiethoxysilane.

[0024] Secondly, the method for preparing a UV conductive frame adhesive for bonding flexible and bendable substrates provided in this application adopts the following technical solution:

[0025] A method for preparing a UV conductive frame adhesive for bonding flexible and bendable substrates includes the following steps:

[0026] S1. Mix polyurethane acrylate and photoinitiator evenly according to the raw material ratio to obtain an active mixture system;

[0027] S2. Add the mixed acrylic monomer and coupling agent to the active mixture to obtain the organic active system;

[0028] S3. Add the conductive filler to the organic active system and mix the conductive UV adhesive.

[0029] S4. Add 30% zirconium by mass and grind, then vacuum to obtain a uniform, bubble-free conductive UV adhesive.

[0030] By adopting the above technical solution

[0031] In summary, this application has the following beneficial effects:

[0032] 1. The raw materials used in the preparation of the UV conductive frame adhesive of this application contain no residual ions in the mixed acrylic monomers, and there is no risk of migration and corrosion. By mixing monofunctional and modified trifunctional acrylic monomers in a specific ratio, the curing speed, crosslinking density, flexibility and viscosity of the adhesive can be adjusted, breaking through the bottleneck of flexibility-polarity-weather resistance, and adapting to flexible screen deformation scenarios. It can also promote the dispersion of solid conductive fillers, reduce resistivity and improve conductivity. The nano-conductive particles ATO have good dispersion, good optical transmittance at high concentrations, and the surface passivation layer has a good water and oxygen barrier effect. In the ATO-acrylic acid system, it can achieve good conductivity and optical performance, and has a higher cost performance.

[0033] 2. In the processing technology of this application, zirconium beads are added to grind ATO. Since the hardness of ATO matches that of zirconium beads well, the particle breakage rate during grinding is controlled within 15%, which makes it less prone to plastic deformation, maintains the original crystal structure, ensures the stability of the conductive network, and effectively inhibits ion migration. In the double 85 test, the volume resistivity change rate of the ATO-acrylic acid system is low, and the performance is more stable.

[0034] 3. The UV conductive frame adhesive of this application adopts room temperature UV single-step curing, which has fast free radical polymerization rate, high bonding strength and high transparency. Compared with traditional acrylic conductive adhesives that are mainly thermosetting or dual-curing, it does not require post-baking at 80-120℃, avoiding problems such as aggravating the warping of flexible substrates, introducing thermal stress, affecting device reliability, causing adhesive layer bulging and accelerating phase separation. At the same time, polyurethane acrylate, as the formulation skeleton, provides the adhesive with mechanical properties, flexibility and bending durability, enhances the interfacial bonding with the substrate, improves the impact resistance and crack resistance of the adhesive layer, and enhances durability. Detailed Implementation

[0035] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments, further clarifies the invention. It should be understood that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0036] The purpose of the present invention will be illustrated by the following examples. The components of the composition are described in parts by weight as a general standard. Unless otherwise specified, for the sake of brevity, "parts" and parts by weight are the same in the embodiments of the present invention.

[0037] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. All reagents and instruments used, unless otherwise specified below, are commercially available products.

[0038] Performance testing

[0039] (a) Conductivity test

[0040] Each UV conductive frame adhesive is uniformly coated on the glass substrate with a thickness of about 50μm, and then UV cured. The curing energy is set according to the actual adhesive characteristics to ensure complete curing. After curing, the sample is cut into appropriate sizes for testing.

[0041] The volume resistivity of the UV conductive frame adhesives prepared in each embodiment and comparative example after curing was measured using a four-probe resistance tester to evaluate their conductivity. The lower the volume resistivity, the better the conductivity.

[0042] (ii) Flexibility test

[0043] A UV conductive adhesive was coated onto a PET film with a thickness of 30 μm. After UV curing, the film was cut into strips of specified size for testing.

[0044] The cured UV conductive frame adhesive was subjected to a bending tester. The sample was fixed on the bending tester and repeatedly bent at a certain bending radius of 2mm. The number of bends was recorded until the conductivity of the sample decreased significantly, for example, the volume resistivity increased by more than 50% of the initial value. This was used to evaluate its flexibility and bending resistance.

[0045] (iii) Transmittance test

[0046] A UV conductive adhesive was coated onto a transparent glass substrate with a thickness of 20 μm, and then tested after UV curing.

[0047] The average transmittance of each sample in the visible light wavelength range of 400-800 nm was measured using a UV-Vis spectrophotometer to evaluate its optical performance.

[0048] (iv) Adhesion performance test

[0049] UV conductive adhesive was uniformly coated onto the surfaces of two clean glass substrates, with a coating area of ​​1 cm². 2 Then, the two substrates are bonded together and UV cured. After curing, the connection strength is tested.

[0050] The cured UV conductive frame adhesive is used to bond two glass substrates. After curing, a push tester is used to push one of the substrates at a certain speed, and the maximum connection strength when the two substrates are separated is recorded to evaluate its bonding strength. The greater the connection strength, the better the bonding performance.

[0051] (v) Stability test for resistance to damp heat aging

[0052] Samples were prepared according to the sample preparation methods for conductivity and flexibility tests, and then placed in a constant temperature and humidity test chamber for testing.

[0053] The cured sample was placed in a constant temperature and humidity test chamber, with the temperature set at 85℃ and the humidity at 85%. After a certain period of 480 hours, it was taken out and its volume resistivity change rate and bending performance change were measured to evaluate its stability under humid and hot conditions. The smaller the volume resistivity change rate and the smaller the bending performance change, the better the stability against humid and hot aging.

[0054] Example 1

[0055] A UV conductive frame adhesive for bonding flexible and bendable substrates, the raw materials used in its preparation are composed of the following components:

[0056] 40% polyurethane acrylate, specifically Lankel L-8406;

[0057] 45% mixed acrylic monomers, of which 7.5% are monofunctional acrylic monomers, specifically β-carboxyethyl acrylate and 37.5% are modified trifunctional acrylic monomers, specifically 6(ethoxy)trimethylolpropane triacrylate.

[0058] 4.5% photoinitiator, specifically 2-hydroxy-2-methylphenylacetone;

[0059] 0.5% coupling agent, specifically 3-glycidyl etheroxypropyl diethoxysilane

[0060] 10% conductive filler, specifically ATO with a particle size of 5-10 nm.

[0061] And it is prepared by the following method:

[0062] S1. Mix polyurethane acrylate and photoinitiator evenly to obtain an active mixture system;

[0063] S2. Add the mixed acrylic monomer and coupling agent to the S1 active mixing system and stir to obtain the organic active system;

[0064] S3. Continue to add conductive filler, mix well, then add 30% zirconium beads by mass and grind. After grinding, vacuum degas to obtain a uniform, bubble-free conductive UV adhesive.

[0065] Examples 2-4

[0066] A UV conductive frame adhesive for bonding flexible and bendable substrates is prepared in a manner basically the same as in Example 1, with the only difference being the amount of each component used. Specific details are shown in the table below.

[0067]

[0068] Example 5

[0069] A UV conductive frame adhesive for bonding flexible and bendable substrates is prepared in a manner similar to that of Example 1, with the only difference being that the monofunctional acrylic monomer in the mixed acrylic monomer is isobornyl acrylate, and the modified trifunctional acrylic monomer is 9(ethoxy)trimethylolpropane triacrylate.

[0070] Example 6

[0071] A UV conductive frame adhesive for bonding flexible and bendable substrates is prepared in a manner similar to that of Example 1, with the only difference being that the monofunctional acrylic monomer in the mixed acrylic monomers is a blend of isoborneol acrylate and β-carboxyethyl acrylate in a specific ratio of 1:1.

[0072] Example 7

[0073] A UV conductive frame adhesive for bonding flexible and bendable substrates is prepared in a manner similar to that of Example 1, with the only difference being that the modified trifunctional acrylic monomer in the mixed acrylic monomers is a blend of 6(ethoxy)trimethylolpropane triacrylate and 9(ethoxy)trimethylolpropane triacrylate in a ratio of 1:1.

[0074] Example 8

[0075] A UV conductive frame adhesive for bonding flexible and bendable substrates is prepared in a manner similar to that of Example 1, with the only difference being that the monofunctional acrylic monomer in the mixed acrylic monomers is a blend of isoborneol acrylate and β-carboxyethyl acrylate in a 1:1 ratio; and the modified trifunctional acrylic monomer is a blend of 6(ethoxy)trimethylolpropane triacrylate and 9(ethoxy)trimethylolpropane triacrylate in a 1:1 ratio.

[0076] Examples 9-11

[0077] A UV conductive frame adhesive for bonding flexible and bendable substrates is prepared in a manner basically the same as in Example 1, with the only difference being the different ratios of monofunctional and modified trifunctional monomers in the mixed acrylic monomers. The specific ratios are shown in the table below.

[0078]

[0079] Comparative Example 1

[0080] A UV conductive frame adhesive for bonding flexible and bendable substrates is prepared in a manner similar to that of Example 1, with the only difference being that the acrylic monomer mixture in the raw materials contains only monofunctional acrylic monomers, specifically β-carboxyethyl acrylate.

[0081] Comparative Example 2

[0082] A UV conductive frame adhesive for bonding flexible and bendable substrates is prepared in a manner similar to that of Example 1, with the only difference being that the acrylic monomer mixture in the raw materials contains only modified trifunctional acrylic monomers, specifically 6(ethoxy)trimethylolpropane triacrylate.

[0083] Comparative Example 3

[0084] A UV conductive frame adhesive for bonding flexible and bendable substrates is prepared in a manner similar to that of Example 1, with the only difference being that the conductive filler used in the preparation is 20nm nano silver powder, purchased from Ningbo Bohuas Brofos-Ag-20.

[0085] Comparative Example 4

[0086] A UV conductive frame adhesive for bonding flexible and bendable substrates is prepared using the same raw materials as in Example 1, except that zirconium beads are not added for grinding in preparation step S3.

[0087] Following the aforementioned performance testing methods, various performance tests were conducted on the UV conductive sealant prepared in each embodiment and comparative example. The test results are shown in the table below.

[0088]

[0089] As can be seen from the table above, Example 1 performed excellently in all performance tests, with a volume resistivity as low as 2.34 × 10⁻⁶. 10 The high resistivity (Ω·cm) is attributed to the reasonable raw material ratio, especially the specific ratio of monofunctional and modified trifunctional acrylic monomers in the mixed acrylic monomers, which effectively promotes the uniform dispersion of solid conductive fillers, thereby reducing resistivity and exhibiting good conductivity. The high bending resistance is also attributed to the synergistic effect of monofunctional acrylic monomers and modified trifunctional acrylic monomers, which adjusts the flexibility and crosslinking density of the adhesive. At the same time, polyurethane acrylate, as a skeleton, provides excellent flexibility and bending durability, giving it excellent flexibility and bending resistance.

[0090] With an average transmittance of 92.0%, the quantum size effect of ATO nanoparticles reduces light scattering loss, giving the frame adhesive high transmittance and meeting the optical performance requirements of flexible display devices. The maximum bonding strength is 35.3 MPa. The polar groups in the polyurethane acrylate enhance the interfacial bonding force between the adhesive and the substrate, demonstrating good adhesion performance.

[0091] In terms of resistance to damp heat aging, the volume resistivity change rate is only 15.3%, and the SnO2 content on the ATO surface exceeds 90%, which effectively inhibits ion migration. This indicates that it has good resistance to damp heat aging. Overall, Example 1 is the optimal example.

[0092] In Examples 2-10, the overall performance was also quite good, although it was slightly inferior to that of Example 1. However, the performance of Example 11 was unsatisfactory. Its conductivity, flexibility, adhesion and resistance to humid heat aging were significantly lower than those of other examples. This is because the ratio of monofunctional monomer to modified trifunctional monomer in Example 11 deviated significantly from the optimal range. When this ratio was out of balance, it had a multifaceted negative impact on the performance of the adhesive layer.

[0093] The performance of Comparative Examples 1-4 was inferior to that of the Example. In terms of conductivity, the volume resistivity was significantly higher than that of the Example. Comparative Examples 1 and 2 had poor conductivity because they were composed of a single acrylic monomer, which could not effectively adjust the adhesive properties. Comparative Example 3 used nano-silver powder as a conductive filler, but its conductivity was not as stable and cost-effective as that achieved by ATO nanoparticles in the ATO-acrylic acid system in the Example. Comparative Example 4 did not add zirconium beads for grinding, and the uneven dispersion of ATO particles also reduced conductivity.

[0094] In terms of flexibility, the number of bends was much lower than in other examples. Comparative Examples 1 and 2 could not form a suitable cross-linking network due to the mixed acrylic monomer components. The nano-silver powder in Comparative Example 3 may have affected the flexibility of the adhesive layer. In Comparative Example 4, the lack of grinding resulted in ATO particles affecting the uniformity of the adhesive layer, all of which reduced flexibility. In terms of transmittance, Comparative Examples 1-4 were all lower than in other examples, indicating that the raw material ratio and preparation process have a significant impact on transmittance. In terms of adhesion performance, the maximum bonding strength was lower than in other examples, possibly due to unreasonable raw material ratio or defects in the preparation process leading to a decrease in interfacial bonding force. In terms of resistance to humid heat aging, the change rate of volume resistivity was much higher than in other examples, indicating that the selection of raw materials and the preparation process have a significant impact on resistance to humid heat aging.

[0095] The above are all modifications that can be made to this embodiment without contributing any inventive step, or solutions that clearly constitute technical teaching, after reading this specification. However, as long as they are within the scope of the claims of this application, they should be protected by patent law.

Claims

1. A UV conductive frame adhesive for bonding flexible and bendable substrates, characterized in that, The raw materials for preparation include the following components: Polyurethane acrylate 30-60%; mixed acrylic monomers 20-50%; photoinitiator 3-6%; coupling agent 0.5-5%; conductive filler 10-30%; The mixed acrylic monomers include monofunctional acrylic monomers and modified trifunctional acrylic monomers, and the mass ratio of the monofunctional acrylic monomers to the modified trifunctional acrylic monomers is 1:2-6. The modified trifunctional acrylic monomer is a trifunctional acrylic monomer in which -CH2-CH2-O- or -CH2-CH(CH3)-O- is introduced, including one or more of 3(ethoxy)trimethylolpropane triacrylate, 6(ethoxy)trimethylolpropane triacrylate, 9(ethoxy)trimethylolpropane triacrylate, 15(ethoxy)trimethylolpropane triacrylate, 20(ethoxy)trimethylolpropane triacrylate, and 3(propoxy)trimethylolpropane triacrylate; The conductive filler is an inorganic metal oxide (ATO) with a particle size of 5-10 nm. Furthermore, the UV conductive frame adhesive for bonding flexible and bendable substrates is prepared by the following method: S1. Mix polyurethane acrylate and photoinitiator evenly according to the raw material ratio to obtain an active mixture system; S2. Add the mixed acrylic monomer and coupling agent to the active mixture to obtain the organic active system; S3. Add the conductive filler to the organic active system and mix the conductive UV adhesive. S4. Add 30% zirconium by mass and grind, then vacuum to obtain a uniform, bubble-free conductive UV adhesive.

2. The UV conductive frame adhesive for bonding flexible and bendable substrates according to claim 1, characterized in that, The monofunctional acrylic monomers include one or more of the following: β-carboxyethyl acrylate, isobornyl methacrylate, isobornyl acrylate, tetrahydrofuran acrylate, isodeyl acrylate, caprolactone acrylate, isooctyl acrylate, stearic acid acrylate, isodeyl methacrylate, stearic acid methacrylate, (ethoxy)phenol acrylate, 2(ethoxy)phenol acrylate, 4(ethoxy)phenol acrylate, 2-phenoxyethyl methacrylate, o-phenylphenoxyethyl acrylate, ethoxyethoxyethyl acrylate, 4(ethoxy)nonylphenol acrylate, tetrahydrofurfuryl acrylate, cyclotrimethylolpropane formal acrylate, and trimethylolcyclohexyl acrylate.

3. The UV conductive frame adhesive for bonding flexible and bendable substrates according to claim 1, characterized in that, The polyurethane acrylate has a viscosity of 2000-40000cps at 25°C, including one or two of the following: Lankel L-8406, Songda SD7832A, SD860, SD867, SD877, Ruiang GENOMER 4316, GENOMER 5271, and Runao FSP5894.

4. The UV conductive frame adhesive for bonding flexible and bendable substrates according to claim 1, characterized in that, The photoinitiator is one or more of the following: 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone, 2-hydroxy-2-methylphenylpropanone, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 1-hydroxycyclohexylphenyl ketone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, 2,4-diethylthioxanthone, benzophenone, and bibenzoyl.

5. The UV conductive frame adhesive for bonding flexible and bendable substrates according to claim 1, characterized in that, The coupling agent is a silane coupling agent, including one of 3-chloropropyltrichlorosilane, 3-chloropropyltrimethoxysilane, n-octyltrimethoxysilane, dodecyltrimethoxysilane, and 3-methacryloyloxypropylmethyldiethoxysilane.

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