High-temperature-resistant and high-air-permeability vehicle-mounted OCA adhesive and preparation method thereof

Abstract

The invention discloses a high-temperature-resistant and high-air-permeability vehicle-mounted OCA adhesive and a preparation method thereof. The OCA adhesive comprises the following raw material components in parts by weight: 40-80 parts of 2-ethylhexyl acrylate; 5 to 20 parts of tetrahydrofuran acrylate; 5 to 20 parts of hydroxybutyl acrylate; 10 to 30 parts of cyclohexyl acrylate; 1.5 to 6 parts of nano particles; 0.45 to 1.8 parts of a photoinitiator; 0.5 to 2 parts of a silane coupling agent; and 0.05 to 0.2 part of 1, 6-hexanediol diacrylate. The OCA optical cement is prepared by adopting a UV curing process, and performance optimization is realized through molecular structure design; according to the invention, a non-benzene-ring cyclic structure and nano particles are utilized to synergistically act to improve the air permeability of the material, and then the cross-linking agent, the coupling agent, the inorganic nano particles and the photoinitiator are added to prepare the high-temperature-resistant and air-permeable OCA optical adhesive by a UV method.

Description

Technical Field

[0001] This invention relates to the field of optical adhesive materials, and in particular to a high-temperature resistant and highly breathable automotive OCA adhesive and its preparation method. Background Technology

[0002] With the accelerated development of automotive intelligence and electrification, the number and size of in-vehicle displays have experienced explosive growth. Industry data shows that in 2023, the average number of screens per vehicle reached 2.3, a 115% increase compared to 2018, directly driving the compound annual growth rate of demand for optical pressure-sensitive adhesives (OCA) to exceed 18%. However, due to the drastic temperature changes (-40℃ to 85℃ or even higher) and the confined space of the vehicle interior, coupled with continuous sunlight exposure (UV and IR), the durability of OCA is severely tested. Currently, polycarbonate (PC) and glass are commonly used as substrates for in-vehicle screens. When the ambient temperature reaches above 80℃, the molecular chain movement of PC material intensifies, ester bonds break, and CO2 gas is generated. The dense cross-linked network of traditional OCA hinders gas escape, creating localized pressure. Finally, when the gas accumulates to a critical value, it breaks through the adhesive layer interface, forming visible bubbles, severely affecting display quality and product yield. This OCA product maintains over 95% adhesion even under high temperature and high humidity conditions. Its unique feature is that, even under ultra-high temperature conditions, the material's air permeability can effectively reduce the air pressure between the adhesive layer and the PC surface caused by the release of carbon dioxide from the PC substrate, thereby preventing the formation of bubbles and ensuring that OCA and the PC substrate maintain good adhesion at high temperatures.

[0003] Publication No. CN 118978880 A discloses a high-performance OCA optical adhesive suitable for automotive environments and its preparation process. The specific implementation process is as follows: First, ethyl acetate is used as a solvent to fully dissolve a modified polyester material, forming a homogeneous mixed solution. Then, this solution is compounded with a polyacrylate matrix material, and various functional additives such as heat stabilizers, performance enhancers, crosslinking modifiers, silane coupling agents, and photoinitiators are added sequentially. After thorough mixing, the final product is obtained. Although this optical adhesive exhibits excellent high-temperature resistance, experimental verification shows that its overall performance still has certain limitations, making it difficult to simultaneously meet multiple requirements such as high-temperature stability, tolerance to humid and hot environments, and UV protection. Especially in actual automotive applications, due to long-term exposure to sunlight and UV radiation, the adhesive is prone to photoaging, leading to problems such as adhesive performance degradation and material yellowing, which in turn affects the image clarity and visual effect of automotive display devices. This technical defect directly restricts the long-term reliability of the product in harsh automotive environments.

[0004] CN119931513 A discloses a method for preparing an automotive OCA (Optical Adhesive Carrier). This method involves mixing and stirring isooctyl acrylate, isobornyl acrylate, acryloylmorpholine, dodecyl acrylate, N-vinylpyrrolidone, a crosslinking agent, and a photoinitiator, followed by filtration and degassing to obtain an acrylic adhesive. The resulting acrylic adhesive is then coated onto a release film and irradiated with a halogen lamp to obtain the automotive OCA optical adhesive. Test data shows that the optical adhesive maintains over 97% tackiness after rigorous environmental testing, including high temperature and humidity (85℃ / 85%RH), Q-SUN UV aging, and thermal cycling from -40℃ to 85℃, demonstrating excellent weather resistance. However, this patented technology does not address the optimization of material permeability, which may lead to interfacial bubble problems due to gas release from the substrate at high temperatures. Future research could improve the material's permeability by introducing microporous structures or adding permeability enhancers, thereby further improving the long-term reliability of the product under extreme temperature conditions. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a high-temperature resistant and highly breathable automotive OCA adhesive and its preparation method, addressing the shortcomings of the prior art.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a high-temperature resistant and highly breathable automotive OCA adhesive, comprising the following raw material components by weight: 40-80 parts of isooctyl acrylate; 5-20 parts of tetrahydrofuran acrylate; 5-20 parts of hydroxybutyl acrylate; 10-30 parts of cyclohexyl acrylate; 1.5-6 parts of nanoparticles; 0.45-1.8 parts of photoinitiator; 0.5-2 parts of silane coupling agent; 0.05-0.2 parts of 1,6-hexanediol diacrylate.

[0007] Preferably, the nanoparticles are nano-SiO2.

[0008] Preferably, the photoinitiator comprises 0.15-0.6 parts of type 184 photoinitiator and 0.3-1.2 parts of type 651 photoinitiator.

[0009] Preferably, the silane coupling agent is silane coupling agent A-172.

[0010] Preferably, the high-temperature resistant and highly breathable automotive OCA adhesive comprises the following raw material components in parts by weight: 60 parts of isooctyl acrylate; 10 parts of tetrahydrofuran acrylate; 10 parts of hydroxybutyl acrylate; 20 parts of cyclohexyl acrylate; 3 parts of nano-SiO2; 0.3 parts of type 184 photoinitiator; 0.6 parts of type 651 photoinitiator; 1 part of silane coupling agent A-172; 0.1 parts of 1,6-hexanediol diacrylate.

[0011] Preferably, the high-temperature resistant and highly breathable automotive OCA adhesive comprises the following raw material components in parts by weight: 60 parts of isooctyl acrylate; 5 parts of tetrahydrofuran acrylate; 10 parts of hydroxybutyl acrylate; 25 parts of cyclohexyl acrylate; 3 parts of nano-SiO2; 0.3 parts of type 184 photoinitiator; 0.6 parts of type 651 photoinitiator; 1 part of silane coupling agent A-172; 0.1 parts of 1,6-hexanediol diacrylate.

[0012] Preferably, the high-temperature resistant and highly breathable automotive OCA adhesive comprises the following raw material components in parts by weight: 60 parts of isooctyl acrylate; 15 parts of tetrahydrofuran acrylate; 10 parts of hydroxybutyl acrylate; 15 parts of cyclohexyl acrylate; 3 parts of nano-SiO2; 0.3 parts of type 184 photoinitiator; 0.6 parts of type 651 photoinitiator; 1 part of silane coupling agent A-172; 0.1 parts of 1,6-hexanediol diacrylate.

[0013] Preferably, the high-temperature resistant and highly breathable automotive OCA adhesive comprises the following raw material components in parts by weight: 60 parts of isooctyl acrylate; 20 parts of tetrahydrofuran acrylate; 10 parts of hydroxybutyl acrylate; 10 parts of cyclohexyl acrylate; 3 parts of nano-SiO2; 0.3 parts of type 184 photoinitiator; 0.6 parts of type 651 photoinitiator; 1 part of silane coupling agent A-172; 0.1 parts of 1,6-hexanediol diacrylate.

[0014] This invention also provides a method for preparing the high-temperature resistant and highly breathable automotive OCA adhesive as described above, comprising the following steps: Step 1: Mix isooctyl acrylate, tetrahydrofuran acrylate, hydroxybutyl acrylate, cyclohexyl acrylate and type 184 photoinitiator, purge with nitrogen to remove air, and stir. Step 2: Turn on the UV lamp for irradiation. After the temperature of the reactants reaches the target level, turn off the UV lamp. At this point, prepolymer 1 is obtained. Step 3: Add type 651 photoinitiator, type 172 silane coupling agent, nanoparticles and HDDA to prepolymer 1, stir, degas and coat to obtain the high temperature resistant and high air permeability automotive OCA adhesive.

[0015] Preferably, the preparation method of the high-temperature resistant and highly breathable automotive OCA adhesive includes the following steps: Step 1: Add isooctyl acrylate, tetrahydrofuran acrylate, hydroxybutyl acrylate, cyclohexyl acrylate and type 184 photoinitiator into a glass reactor, purge the air from the reactor with nitrogen and keep the temperature at 20-30℃, and stir at 75-300 r / min for 10-40 min. Step 2: Turn on the UV lamp to irradiate the glass reactor, controlling the irradiation energy to 500-2000 mJ / cm². 2 After the temperature of the reactants rises by 10-30°C, the UV lamp is turned off, and prepolymer 1 is obtained. Step 3: Add type 651 photoinitiator, type 172 silane coupling agent, nanoparticles and HDDA to prepolymer 1, stir, degas and coat to obtain the high temperature resistant and high air permeability automotive OCA adhesive.

[0016] The beneficial effects of this invention are: This invention provides a high-temperature resistant and highly breathable automotive OCA adhesive and its preparation method. The invention uses a UV curing process to prepare the OCA optical adhesive and achieves performance optimization through molecular structure design. The invention utilizes the synergistic effect of non-benzene ring cyclic structures and nanoparticles to enhance the breathability of the material. Then, a crosslinking agent, coupling agent, inorganic nanoparticles, and photoinitiator are added to prepare the high-temperature resistant and breathable OCA optical adhesive via a UV method.

[0017] This invention selects isooctyl acrylate and hydroxyethyl acrylate as flexible segments to ensure the colloid has good flexibility and initial tack. Simultaneously, it innovatively uses cyclohexyl acrylate and tetrahydrofuran acrylate to replace traditional benzene-ring-containing monomers. These two cyclic monomers significantly improve UV aging resistance due to their shorter UV absorption cutoff wavelength (<250nm), and their rigid cyclic structure also endows the molecular chain with higher thermal stability, improving high-temperature resistance by more than 30%. Furthermore, through the synergistic effect of cyclic monomers and inorganic nanoparticles, this invention constructs a nanoscale porous structure with a size controlled in the 10-50nm range within the colloid, effectively improving air permeability and mitigating interfacial bubble problems at high temperatures. Compared with traditional OCA in terms of weather resistance and air permeability, this design is more suitable for harsh environments such as automotive displays.

[0018] This invention provides an automotive OCA that combines high temperature resistance and breathability. Under high temperature conditions, gas concentrates on the bonding surface, and the nanoscale pores in the material allow gas to pass through smoothly, thereby solving the problem of air bubbles after automotive OCA bonding under high temperature conditions. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to embodiments, so that those skilled in the art can implement it based on the description.

[0020] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0021] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials and reagents used in the following examples are commercially available. For examples where specific conditions are not specified, conventional conditions or conditions recommended by the manufacturer are followed. For reagents or instruments whose manufacturers are not specified, they are all commercially available products.

[0022] This invention provides a high-temperature resistant and highly breathable automotive OCA adhesive, comprising the following raw material components in parts by weight: 40-80 parts of isooctyl acrylate; 5-20 parts of tetrahydrofuran acrylate; 5-20 parts of hydroxybutyl acrylate; 10-30 parts of cyclohexyl acrylate; 1.5-6 parts of nanoparticles; 0.45-1.8 parts of photoinitiator; 0.5-2 parts of silane coupling agent; 0.05-0.2 parts of 1,6-hexanediol diacrylate.

[0023] In a preferred embodiment, the nanoparticles are nano-SiO2.

[0024] In a preferred embodiment, the photoinitiator comprises 0.15-0.6 parts of type 184 photoinitiator and 0.3-1.2 parts of type 651 photoinitiator.

[0025] In a preferred embodiment, the silane coupling agent is silane coupling agent A-172.

[0026] In a preferred embodiment, the high-temperature resistant and highly breathable automotive OCA adhesive comprises the following raw material components in parts by weight: 60 parts of isooctyl acrylate; 10 parts of tetrahydrofuran acrylate; 10 parts of hydroxybutyl acrylate; 20 parts of cyclohexyl acrylate; 3 parts of nano-SiO2; 0.3 parts of type 184 photoinitiator; 0.6 parts of type 651 photoinitiator; 1 part of silane coupling agent A-172; 0.1 parts of 1,6-hexanediol diacrylate.

[0027] In a preferred embodiment, the high-temperature resistant and highly breathable automotive OCA adhesive comprises the following raw material components in parts by weight: 60 parts of isooctyl acrylate; 5 parts of tetrahydrofuran acrylate; 10 parts of hydroxybutyl acrylate; 25 parts of cyclohexyl acrylate; 3 parts of nano-SiO2; 0.3 parts of type 184 photoinitiator; 0.6 parts of type 651 photoinitiator; 1 part of silane coupling agent A-172; 0.1 parts of 1,6-hexanediol diacrylate.

[0028] In a preferred embodiment, the high-temperature resistant and highly breathable automotive OCA adhesive comprises the following raw material components in parts by weight: 60 parts of isooctyl acrylate; 15 parts of tetrahydrofuran acrylate; 10 parts of hydroxybutyl acrylate; 15 parts of cyclohexyl acrylate; 3 parts of nano-SiO2; 0.3 parts of type 184 photoinitiator; 0.6 parts of type 651 photoinitiator; 1 part of silane coupling agent A-172; 0.1 parts of 1,6-hexanediol diacrylate.

[0029] Preferably, the high-temperature resistant and highly breathable automotive OCA adhesive is characterized by comprising the following raw material components in parts by weight: 60 parts of isooctyl acrylate; 20 parts of tetrahydrofuran acrylate; 10 parts of hydroxybutyl acrylate; 10 parts of cyclohexyl acrylate; 3 parts of nano-SiO2; 0.3 parts of type 184 photoinitiator; 0.6 parts of type 651 photoinitiator; 1 part of silane coupling agent A-172; 0.1 parts of 1,6-hexanediol diacrylate.

[0030] This invention also provides a method for preparing the above-mentioned high-temperature resistant and highly breathable automotive OCA adhesive, comprising the following steps: Step 1: Mix isooctyl acrylate, tetrahydrofuran acrylate, hydroxybutyl acrylate, cyclohexyl acrylate and type 184 photoinitiator, purge with nitrogen to remove air, and stir. Step 2: Turn on the UV lamp for irradiation. After the temperature of the reactants reaches the target level, turn off the UV lamp. At this point, prepolymer 1 is obtained. Step 3: Add type 651 photoinitiator, type 172 silane coupling agent, nanoparticles and HDDA to prepolymer 1, stir, degas and coat to obtain high temperature resistant and high air permeability automotive OCA adhesive.

[0031] In a preferred embodiment, the preparation method of the high-temperature resistant and highly breathable automotive OCA adhesive includes the following steps: Step 1: Add isooctyl acrylate, tetrahydrofuran acrylate, hydroxybutyl acrylate, cyclohexyl acrylate and type 184 photoinitiator into a glass reactor, purge the air from the reactor with nitrogen and keep the temperature at 20-30℃, and stir at 75-300 r / min for 10-40 min. Step 2: Turn on the UV lamp to irradiate the glass reactor, controlling the irradiation energy to 500-2000 mJ / cm². 2 After the temperature of the reactants rises by 10-30°C, the UV lamp is turned off, and prepolymer 1 is obtained. Step 3: Add type 651 photoinitiator, type 172 silane coupling agent, nanoparticles and HDDA to prepolymer 1, stir, degas and coat to obtain high temperature resistant and high air permeability automotive OCA adhesive.

[0032] In a preferred embodiment, the preparation method of the high-temperature resistant and highly breathable automotive OCA adhesive includes the following steps: Step 1: Add isooctyl acrylate, tetrahydrofuran acrylate, hydroxybutyl acrylate, cyclohexyl acrylate and type 184 photoinitiator into a glass reactor, purge the air from the reactor with nitrogen and keep at 25°C, stirring at 150 R / min for 20 min. Step 2: Turn on the UV lamp to irradiate the glass reactor, controlling the irradiation energy to 1000 mJ / cm². 2 After the temperature of the reactants rises by 15°C, the UV lamp is turned off, and prepolymer 1 is obtained. Step 3: Add type 651 photoinitiator, type 172 silane coupling agent, nanoparticles and HDDA to prepolymer 1, stir, degas and coat to obtain high temperature resistant and high air permeability automotive OCA adhesive.

[0033] The OCA optical adhesive prepared by UV polymerization in this invention has at least the following improvements: First, in terms of monomer selection, the traditional acrylate monomers containing benzene ring structures were abandoned, and cyclohexane acrylate was used instead as the main raw material. This improvement significantly enhances the material's resistance to yellowing and high temperature resistance, because the cyclohexane structure has a lower UV absorption cutoff wavelength than the benzene ring, thus exhibiting superior UV aging resistance.

[0034] Secondly, the OCA material of the present invention forms a nanoscale channel network inside the material by adding nanoparticles (nano SiO2); this unique microstructure gives the material good air permeability. When in a high-temperature environment, these nanochannels can provide a flow path for the gas accumulated between the interfaces, which can effectively reduce the interfacial gas pressure and thus significantly reduce the generation of interfacial defects such as bubbles.

[0035] This invention innovatively combines high-temperature resistance with breathability, successfully developing a new type of automotive OCA material. This material not only maintains excellent bonding strength under high-temperature environments but also possesses unique breathability, achieving a fundamental shift from the traditional "blocking" approach to the "ventilation" concept. Compared to conventional automotive OCA products, this innovative design fundamentally solves the technical problem of interface bubble formation under high-temperature conditions by establishing an effective exhaust channel, demonstrating more reliable long-term performance.

[0036] The above is the general concept of the present invention. Based on this, detailed embodiments and comparative examples are provided below to further illustrate the present invention.

[0037] Example 1 A high-temperature resistant and highly breathable automotive OCA adhesive, comprising the following raw material components in parts by weight: 60 parts isooctyl acrylate; 10 parts tetrahydrofuran acrylate; 10 parts hydroxybutyl acrylate; 20 parts cyclohexyl acrylate; 3 parts nano-SiO2 (particle size 5-150 nm); 0.3 parts type 184 photoinitiator; 0.6 parts type 651 photoinitiator; 1 part silane coupling agent A-172; 0.1 parts 1,6-hexanediol diacrylate.

[0038] The preparation method of this automotive OCA adhesive includes the following steps: Step 1: Add isooctyl acrylate, tetrahydrofuran acrylate, hydroxybutyl acrylate, cyclohexyl acrylate and type 184 photoinitiator into a glass reactor, purge the air from the reactor with nitrogen and keep at 25°C, stirring at 150 R / min for 20 min. Step 2: Turn on the UV lamp to irradiate the glass reactor, controlling the irradiation energy to 1000 mJ / cm². 2 The reaction begins as the temperature rises continuously. After the temperature of the reactants rises by 15°C, the UV lamp is turned off, and prepolymer 1 is obtained. Step 3: Add type 651 photoinitiator, type 172 silane coupling agent, nano SiO2 and HDDA to prepolymer 1, stir, degas and coat to obtain a 250µm thick high temperature resistant and high air permeability automotive OCA adhesive.

[0039] Example 2 The only difference between this example and Example 1 is the ratio of the raw material components. Specifically, this example includes the following raw material components by weight: 60 parts isooctyl acrylate; 5 parts tetrahydrofuran acrylate; 10 parts hydroxybutyl acrylate; 25 parts cyclohexyl acrylate; 3 parts nano-SiO2 (particle size 5-150 nm); 0.3 parts type 184 photoinitiator; 0.6 parts type 651 photoinitiator; 1 part silane coupling agent A-172; 0.1 parts 1,6-hexanediol diacrylate.

[0040] Example 3 The only difference between this example and Example 1 is the ratio of the raw material components. Specifically, this example includes the following raw material components by weight: 60 parts of isooctyl acrylate; 15 parts of tetrahydrofuran acrylate; 10 parts of hydroxybutyl acrylate; 15 parts of cyclohexyl acrylate; 3 parts of nano-SiO2 (particle size 5-150 nm); 0.3 parts of type 184 photoinitiator; 0.6 parts of type 651 photoinitiator; 1 part of silane coupling agent A-172; 0.1 parts of 1,6-hexanediol diacrylate.

[0041] Example 4 The only difference between this example and Example 1 is the ratio of the raw material components. Specifically, this example includes the following raw material components by weight: 60 parts isooctyl acrylate; 20 parts tetrahydrofuran acrylate; 10 parts hydroxybutyl acrylate; 10 parts cyclohexyl acrylate; 3 parts nano-SiO2 (particle size 5-150 nm); 0.3 parts type 184 photoinitiator; 0.6 parts type 651 photoinitiator; 1 part silane coupling agent A-172; 0.1 parts 1,6-hexanediol diacrylate.

[0042] Example 5 The difference between this example and Example 1 lies in the thickness of the OCA. The specific steps in this example are as follows (all figures are parts by weight): Step 1: Add 60 parts of isooctyl acrylate, 10 parts of hydroxybutyl acrylate, 10 parts of tetrahydrofuran acrylate, 20 parts of cyclohexyl acrylate and 0.3 parts of type 184 photoinitiator into the reactor, purge the air in the reactor with nitrogen and keep the solution at an initial temperature of 25°C, and stir at 150 R / min for 20 min. Step 2: Turn on the UV lamp for irradiation (1000mJ / cm²). 2 In the reaction vessel, wait for the temperature to rise continuously to indicate the start of the reaction. When the temperature rises by about 15°C, turn off the UV lamp. At this point, prepolymer 1 is obtained. Step 3: Add 0.6 parts of type 651 photoinitiator, 1 part of type 72 silane coupling agent, 3 parts of nanoparticles and 0.1 parts of 1,6-hexanediol diacrylate (HDDA) to prepolymer 1, stir, degas and coat to obtain a 250µm thick automotive OCA adhesive.

[0043] Comparative Example 1 The difference between this example and Example 1 is that the crosslinking agent HDDA is not added. The specific steps in this example are as follows (all figures are parts by weight): Step 1: Add 60 parts of isooctyl acrylate, 10 parts of tetrahydrofuran acrylate, 10 parts of hydroxybutyl acrylate, 20 parts of cyclohexyl acrylate and 0.3 parts of type 184 photoinitiator into the reactor, purge the air in the reactor with nitrogen and keep the solution at an initial temperature of 25°C, and stir at 150 R / min for 20 min. Step 2: Turn on the UV lamp for irradiation (1000mJ / cm²). 2 In the reaction vessel, wait for the temperature to rise continuously to indicate the start of the reaction. After the temperature rises by 15°C, turn off the UV lamp. At this point, prepolymer 1 is obtained. Step 3: Add 0.6 parts of type 651 photoinitiator, 1 part of type 72 silane coupling agent and 3 parts of nanoparticles to prepolymer 1, stir, degas and coat to obtain a 250µm thick automotive OCA adhesive.

[0044] Comparative Example 2 The difference between this example and Example 1 is that no nanoparticles (SiO2) are added. The specific steps in this example are as follows (all parts by weight): Step 1: Add 60 parts of isooctyl acrylate, 10 parts of tetrahydrofuran acrylate, 10 parts of hydroxybutyl acrylate, 20 parts of cyclohexyl acrylate and 0.3 parts of type 184 photoinitiator into the reactor, purge the air in the reactor with nitrogen and keep the solution at an initial temperature of 25°C, and stir at 150 R / min for 20 min. Step 2: Turn on the UV lamp for irradiation (1000mJ / cm²). 2 In the reaction vessel, wait for the temperature to rise continuously to indicate the start of the reaction. When the temperature rises by 15°C, turn off the UV lamp. At this point, prepolymer 1 is obtained. Step 3: Add 0.6 parts of type 651 photoinitiator, 1 part of type 72 silane coupling agent and 0.1 parts of 1,6-hexanediol diacrylate (HDDA) to prepolymer 1, stir, degas and coat to obtain a 250µm thick automotive OCA adhesive.

[0045] Comparative Example 3 The difference between this example and Example 1 is that cyclohexyl acrylate is not added. The specific steps in this example are as follows (all parts by weight): Step 1: Add 90 parts of isooctyl acrylate, 10 parts of tetrahydrofuran acrylate, 10 parts of hydroxybutyl acrylate and 0.3 parts of type 184 photoinitiator into the reactor, purge the air in the reactor with nitrogen and keep the solution at an initial temperature of 25°C, and stir at 150 R / min for 20 min. Step 2: Turn on the UV lamp for irradiation (1000mJ / cm²). 2 In the reaction vessel, wait for the temperature to rise continuously to indicate the start of the reaction. When the temperature rises by 15°C, turn off the UV lamp. At this point, prepolymer 1 is obtained. Step 3: Add 0.6 parts of type 651 photoinitiator, 1 part of type 72 silane coupling agent, 3 parts of nanoparticles and 0.1 parts of 1,6-hexanediol diacrylate (HDDA) to prepolymer 1, stir, degas and coat to obtain a 250µm thick automotive OCA adhesive.

[0046] Comparative Example 4 The difference between this example and Example 1 is that tetrahydrofuran acrylate is not added. The specific steps in this example are as follows (all figures are parts by weight): Step 1: Add 70 parts of isooctyl acrylate, 10 parts of hydroxybutyl acrylate, 20 parts of cyclohexyl acrylate and 0.3 parts of type 184 photoinitiator into the reactor, purge the air in the reactor with nitrogen and keep the solution at an initial temperature of 25°C, and stir at 150 R / min for 20 min. Step 2: Turn on the UV lamp for irradiation (1000mJ / cm²). 2 In the reaction vessel, wait for the temperature to rise continuously to indicate the start of the reaction. When the temperature rises by about 15°C, turn off the UV lamp. At this point, prepolymer 1 is obtained. Step 3: Add 0.6 parts of type 651 photoinitiator, 1 part of type 72 silane coupling agent, 3 parts of nanoparticles and 0.1 parts of 1,6-hexanediol diacrylate (HDDA) to prepolymer 1, stir, degas and coat to obtain a 250µm thick automotive OCA adhesive.

[0047] Performance testing The performance of the automotive OCA optical adhesives prepared in Examples 1-5 and Comparative Examples 1-4 was tested: 1. Test the bonding properties and air permeability of OCA optical adhesive at room temperature; 2. The adhesion of OCA optical adhesive after aging at 85℃ / 85%RH for 14 days; 3. Test the adhesion of OCA optical adhesive at 95℃; 4. Peel off the light side release film of the prepared OCA and attach it to a 100 µm PET film. Then peel off the heavy side release film and attach it to a 200 µm PC board. After degassing, let it stand for one day and then age it for 1500 hours each under Q-Sun, cold and hot cycling (-40℃~85℃) and high temperature of 100℃. Observe the number of bubbles on the surface, which are in the order of no bubbles, very few bubbles, a few bubbles and a lot of bubbles.

[0048] The test results are shown in Table 1 below: Table 1 As can be seen from the above, the difference between Examples 2-4 and Example 1 lies in the change of raw material ratio. From the results, all four OCAs exhibited high viscosity, high temperature resistance and air permeability at both room temperature and high temperature. The difference between Example 1 and Example 5 lies in the thickness of the OCA. The results show that the greater the thickness of the OCA, the higher the viscosity, while other properties are not significantly different.

[0049] Compared with Example 1, Comparative Example 1 is different in that it does not contain a crosslinking agent. The results show that the viscosity and high temperature resistance of Example 1 are significantly higher. This is because the crosslinking agent makes the crosslinking between molecular chains more uniform, resulting in higher viscosity. The increase in the degree of crosslinking increases the modulus of OCA, thereby significantly improving the high temperature resistance.

[0050] The difference between Comparative Example 2 and Example 1 lies in whether or not nanoparticles were added. The results show that both exhibit high viscosity and high temperature resistance, but show a significant difference in air permeability. This is because the nanopores between the nanoparticles allow gas to pass through better, thereby increasing the air permeability of OCA.

[0051] Comparative Examples 3 and 4 differ from Example 1 in that they contain cyclohexyl acrylate and tetrahydrofuran acrylate. The results show that when the cyclic acrylate monomers are absent in the OCA, the viscosity, high temperature resistance, and air permeability of the OCA decrease. This is because the introduction of cyclic structures can increase the rigidity of the molecular chains, which can improve the viscosity and high temperature resistance of the OCA. The presence of cyclic structures in the OCA increases the gaps between molecular chains, resulting in a large number of pores in the OCA, thereby increasing the air permeability of the material.

[0052] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details.

Claims

1. A high-temperature resistant and highly breathable automotive OCA adhesive, characterized in that, Includes the following raw material components by weight: 40-80 parts of isooctyl acrylate; 5-20 parts of tetrahydrofuran acrylate; 5-20 parts of hydroxybutyl acrylate; 10-30 parts of cyclohexyl acrylate; 1.5-6 parts of nanoparticles; 0.45-1.8 parts of photoinitiator; 0.5-2 parts of silane coupling agent; 0.05-0.2 parts of 1,6-hexanediol diacrylate.

2. The high-temperature resistant and highly breathable automotive OCA adhesive according to claim 1, characterized in that, The nanoparticles are nano-SiO2.

3. The high-temperature resistant and highly breathable automotive OCA adhesive according to claim 1, characterized in that, The photoinitiator consists of 0.15-0.6 parts of type 184 photoinitiator and 0.3-1.2 parts of type 651 photoinitiator.

4. The high-temperature resistant and highly breathable automotive OCA adhesive according to claim 1, characterized in that, The silane coupling agent is silane coupling agent A-172.

5. The high-temperature resistant and highly breathable automotive OCA adhesive according to claim 1, characterized in that, Includes the following raw material components by weight: 60 parts of isooctyl acrylate; 10 parts of tetrahydrofuran acrylate; 10 parts of hydroxybutyl acrylate; 20 parts of cyclohexyl acrylate; 3 parts of nano-SiO2; 0.3 parts of type 184 photoinitiator; 0.6 parts of type 651 photoinitiator; 1 part of silane coupling agent A-172; 0.1 parts of 1,6-hexanediol diacrylate.

6. The high-temperature resistant and highly breathable automotive OCA adhesive according to claim 1, characterized in that, Includes the following raw material components by weight: 60 parts of isooctyl acrylate; 5 parts of tetrahydrofuran acrylate; 10 parts of hydroxybutyl acrylate; 25 parts of cyclohexyl acrylate; 3 parts of nano-SiO2; 0.3 parts of type 184 photoinitiator; 0.6 parts of type 651 photoinitiator; 1 part of silane coupling agent A-172; 0.1 parts of 1,6-hexanediol diacrylate.

7. The high-temperature resistant and highly breathable automotive OCA adhesive according to claim 1, characterized in that, Includes the following raw material components by weight: 60 parts isooctyl acrylate; 15 parts tetrahydrofuran acrylate; 10 parts hydroxybutyl acrylate; 15 parts cyclohexyl acrylate; 3 parts nano-SiO2; 0.3 parts type 184 photoinitiator; 0.6 parts of type 651 photoinitiator; 1 part of silane coupling agent A-172; 0.1 parts of 1,6-hexanediol diacrylate.

8. The high-temperature resistant and highly breathable automotive OCA adhesive according to claim 1, characterized in that, Includes the following raw material components by weight: 60 parts of isooctyl acrylate; 20 parts of tetrahydrofuran acrylate; 10 parts of hydroxybutyl acrylate; 10 parts of cyclohexyl acrylate; 3 parts of nano-SiO2; 0.3 parts of type 184 photoinitiator; 0.6 parts of type 651 photoinitiator; 1 part of silane coupling agent A-172; 0.1 parts of 1,6-hexanediol diacrylate.

9. A method for preparing a high-temperature resistant and highly breathable automotive OCA adhesive as described in any one of claims 1-8, characterized in that, Includes the following steps: Step 1: Mix isooctyl acrylate, tetrahydrofuran acrylate, hydroxybutyl acrylate, cyclohexyl acrylate and type 184 photoinitiator, purge with nitrogen to remove air, and stir. Step 2: Turn on the UV lamp for irradiation. After the temperature of the reactants reaches the target level, turn off the UV lamp. At this point, prepolymer 1 is obtained. Step 3: Add type 651 photoinitiator, type 172 silane coupling agent, nanoparticles and HDDA to prepolymer 1, stir, degas and coat to obtain the high temperature resistant and high air permeability automotive OCA adhesive.

10. The preparation method of the high-temperature resistant and highly breathable automotive OCA adhesive according to claim 9, characterized in that, Includes the following steps: Step 1: Add isooctyl acrylate, tetrahydrofuran acrylate, hydroxybutyl acrylate, cyclohexyl acrylate and type 184 photoinitiator into a glass reactor, purge the air from the reactor with nitrogen and keep the temperature at 20-30℃, and stir at 75-300 r / min for 10-40 min. Step 2: Turn on the UV lamp to irradiate the glass reactor, controlling the irradiation energy to 500-2000 mJ / cm². 2 After the temperature of the reactants rises by 10-30°C, the UV lamp is turned off, and prepolymer 1 is obtained. Step 3: Add type 651 photoinitiator, type 172 silane coupling agent, nanoparticles and HDDA to prepolymer 1, stir, degas and coat to obtain the high temperature resistant and high air permeability automotive OCA adhesive.

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