Preparation method of optical OCA (Optical Clear Adhesive) and application of optical OCA in folding screen of mobile phone

Abstract

The invention discloses a preparation method of an optical OCA (Optical Clear Adhesive) and application of the optical OCA in a mobile phone folding screen, and relates to the technical field of optical cement, the optical OCA is prepared from the following raw materials in parts by weight: 50 parts of acrylate prepolymers, 2-4 parts of 3-allyl-2-mercapto-3H-quinazoline-4-ketone, 1-3 parts of diallyl disulfide, 1-3 parts of 3-[N, N-dimethyl formamide], 1-3 parts of 2, 3, 5-trimethyl-1, 3-pentanediol monoisobutyronitrile, 1-3 parts of 2, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3 The preparation method comprises the following steps: adding 3-5 parts of N, N-dimethyl-[2-(2-methylpropane-2-enoyloxy) ethyl] ammonium] propane-1-sulfonic acid inner salt, 1-3 parts of allyl succinimido carbonate, 2-4 parts of dicyclopentene methacrylate, 1-3 parts of 1, 3, 5-triacryloyl hexahydro-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5- The invention relates to a graphene quantum dot photoinitiator which is prepared from the following components in parts by weight: 1-3 parts of 1, 3, 5-triazine, 0.8-1.2 parts of a photoinitiator, 1-3 parts of an aziridine cross-linking agent, 1-3 parts of graphene quantum dots, 0.8-1.2 parts of a coupling agent and 40-50 parts of a diluent. The optical OCA adhesive is high in light transmittance and bonding strength, good in weather resistance and excellent in folding resistance.

Description

Technical Field

[0001] The present invention relates to the field of optical adhesive technology, and in particular to a method for preparing optical OCA adhesive and its application in mobile phone folding screens. Background Art

[0002] With the rapid development of electronic display technology, foldable mobile phone screens, with their unique foldable features and larger display space, are gradually becoming a new trend in the consumer electronics field. In the manufacturing of foldable mobile phones, optical OCA adhesives are a key material for connecting the display panel and cover plate. Its performance directly affects the display quality and folding reliability of the screen. Therefore, it is particularly important to develop optical OCA adhesives with excellent comprehensive performance and performance stability suitable for foldable mobile phone applications.

[0003] The ideal optical OCA adhesive for mobile phone folding screens needs to have both high light transmittance and bonding strength, excellent flexibility and folding resistance, good weather resistance and stability. However, when traditional optical OCA adhesive is applied to complex optical systems such as folding screens, its light transmittance will drop significantly due to multiple folding and light refraction, resulting in reduced screen brightness and color distortion, affecting the user's visual experience. In addition, the optical OCA adhesives on the market also have more or less technical defects such as insufficient bonding strength, insufficient flexibility and folding resistance, and weather resistance and stability still need to be further improved.

[0004] For example, the Chinese invention patent with authorization announcement number CN113249038B discloses a method for preparing OCA optical adhesive, which uses 3-(2-furyl)-2-propyl acrylate containing a furan group as a comonomer, copolymerizes it with monomers such as hydroxyethyl acrylate and polyethylene glycol monomethyl ether methacrylate, and adds polyamine as a cross-linking agent, so that the prepared OCA optical adhesive has good thermal stability, adhesion and light transmittance. However, the optical OCA adhesive prepared in this way does not have good bending resistance. When used in the bonding of folding screen components, the folding screen will produce creases during long-term use, affecting the use of folding mobile phones and reducing the service life of folding mobile phones, which does not meet actual needs.

[0005] It can be seen that this field still needs a method for preparing optical OCA glue with high transmittance and bonding strength, good weather resistance and excellent folding resistance, and its application in mobile phone folding screens. Summary of the Invention

[0006] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a method for preparing an optical OCA glue with high light transmittance and bonding strength, good weather resistance and excellent folding resistance, as well as its application in mobile phone folding screens.

[0007] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: an optical OCA glue, comprising the following raw materials in parts by weight: 50 parts of acrylate prepolymer, 2-4 parts of 3-allyl-2-mercapto-3H-quinazolin-4-one, 1-3 parts of diallyl disulfide, 3-5 parts of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt, 1-3 parts of allyl succinimidyl carbonate, 2-4 parts of dicyclopentene methacrylate, 1-3 parts of 1,3,5-triacryloylhexahydro-1,3,5-triazine, 0.8-1.2 parts of photoinitiator, 1-3 parts of aziridine crosslinker, 1-3 parts of graphene quantum dots, 0.8-1.2 parts of coupling agent, and 40-50 parts of diluent.

[0008] Preferably, the preparation method of the acrylic ester prepolymer comprises the following steps: under the protection of an inert gas atmosphere, adding isooctyl acrylate, an initiator, a chain transfer agent, an emulsifier, and deionized water into a reactor, stirring and reacting at a constant temperature of 68-72°C for 3-5 hours, then adding a mixed solution of styrene, hydroxyethyl acrylate, and itaconic acid dropwise thereto, and completing the addition within 1 hour. After the addition is completed, the temperature is raised to 78-82°C, and the stirring is continued to keep warm and react for 3-5 hours, cooled, dialyzed, and freeze-dried to obtain the acrylic ester prepolymer.

[0009] Preferably, the inert gas is any one of nitrogen, helium, neon and argon.

[0010] Preferably, the chain transfer agent is 2-(dodecylthiocarbonylthio)-2-methylpropionic acid.

[0011] Preferably, the initiator is azobisisobutyronitrile; and the emulsifier is emulsifier OP-10.

[0012] Preferably, the mass ratio of isooctyl acrylate, initiator, chain transfer agent, emulsifier, deionized water, styrene, hydroxyethyl acrylate, and itaconic acid is 50:0.1:0.1:3:100:15:5:5.

[0013] Preferably, the photoinitiator is benzoin ethyl ether.

[0014] Preferably, the aziridine crosslinking agent is aziridine crosslinking agent XR-100.

[0015] Preferably, the particle size of the graphene quantum dots is 3-5 nm.

[0016] Preferably, the coupling agent is at least one of silane coupling agent KH550, silane coupling agent KH560, and silane coupling agent KH570.

[0017] Preferably, the diluent is at least one of butyl acrylate, hydroxyethyl methacrylate, isobornyl acrylate, and tetrahydrofurfuryl acrylic acid.

[0018] Another object of the present invention is to provide a method for preparing the optical OCA glue, comprising the following steps: mixing the raw materials evenly, vacuum degassing, and evenly coating them on a PET release film through a slit coater, curing them with ultraviolet light for 15-20 minutes, and then baking them in hot air at 80°C for 4-6 minutes to obtain the optical OCA glue.

[0019] Preferably, the UV curing energy is 500-800 mJ / cm².

[0020] Another object of the present invention is to provide an application of the optical OCA glue in a folding screen of a mobile phone, comprising the following steps: laminating the prepared optical OCA glue between the display panel and the cover plate of the folding screen, and laminating them through a hot pressing process, with a hot pressing temperature of 60-80°C, a pressure of 0.5-1MPa, and a time of 1-2 minutes.

[0021] Due to the application of the above technical solution, the present invention has the following beneficial effects: (1) The preparation method of the optical OCA glue disclosed in the present invention has a short process flow, low energy consumption, low dependence on equipment, high preparation efficiency and finished product qualification rate, is suitable for continuous large-scale production, and has high promotion and application value.

[0022] (2) The optical OCA adhesive disclosed in the present invention is made of the following raw materials in parts by weight: 50 parts of acrylate prepolymer, 2-4 parts of 3-allyl-2-mercapto-3H-quinazolin-4-one, 1-3 parts of diallyl disulfide, 3-5 parts of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt, 1-3 parts of allyl succinimidyl carbonate, 2-4 parts of dicyclopentene methacrylate, 1-3 parts of 1,3,5-triacryloylhexahydro-1,3,5-triazine, 0.8-1.2 parts of photoinitiator, 1-3 parts of aziridine crosslinking agent, 1-3 parts of graphene quantum dots, 0.8-1.2 parts of coupling agent, and 40-50 parts of diluent. The interaction and synergy of the various raw materials results in optical OCA adhesives with high light transmittance and bond strength, excellent weather resistance, and superior folding resistance. The simultaneous introduction of mercaptoquinazolinone, zwitterionic salts, succinimidyl carbonate, dicyclopentenylmethyl, ester groups, and triazine structures, through the multiple effects of electronic, steric, and conjugated effects, results in optical OCA adhesives with even higher light transmittance and bond strength, as well as better weather resistance and folding resistance.

[0023] (3) The optical OCA adhesive disclosed in the present invention introduces disulfide bonds through diallyl disulfide, and introduces a zwitterionic salt structure into 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt. The structural rearrangement of the zwitterionic structure and the rupture of the disulfide bond form a dual dissipation path. During the structural rearrangement process, the polar environment of the zwitterionic structure promotes the thiol-disulfide exchange reaction of the disulfide bond. The combined effect of the two can effectively improve the folding resistance, bonding performance, mechanical properties and optical stability, and endow the material with self-healing ability. The acrylic prepolymer soft segment and graphene quantum dots form a dual mechanism of "energy dissipation-stress conduction", which effectively improves the bending resistance and enhances the stability of the bonding performance. The quantum confinement effect of the graphene quantum dots can effectively enhance the tearing strength of the adhesive layer.

[0024] (4) The application of the optical OCA glue disclosed in the present invention in the folding screen of mobile phones has a simple and easy application method and convenient operation and control. It can significantly extend the service life of the equipment and reduce maintenance costs, providing core material support for the folding screen field. DETAILED DESCRIPTION

[0025] The following description is intended to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are merely examples, and those skilled in the art may conceive of other obvious variations.

[0026] Example 1 An optical OCA adhesive is prepared from the following raw materials in parts by weight: 50 parts of an acrylate prepolymer, 2 parts of 3-allyl-2-mercapto-3H-quinazolin-4-one, 1 part of diallyl disulfide, 3 parts of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt, 1 part of allyl succinimidyl carbonate, 2 parts of dicyclopentene methacrylate, 1 part of 1,3,5-triacryloylhexahydro-1,3,5-triazine, 0.8 parts of a photoinitiator, 1 part of an aziridine crosslinking agent, 1 part of a graphene quantum dot, 0.8 parts of a coupling agent, and 40 parts of a diluent.

[0027] The method for preparing an acrylate prepolymer comprises the following steps: adding isooctyl acrylate, an initiator, a chain transfer agent, an emulsifier, and deionized water to a reactor under the protection of an inert gas atmosphere, stirring and reacting at a constant temperature of 68° C. for 3 hours, then dripping a mixed solution of styrene, hydroxyethyl acrylate, and itaconic acid into the reactor, completing the dripping within 1 hour, heating the mixture to 78° C. after completion of the dripping, continuing to stir and react at this temperature for 3-5 hours, cooling, dialyzing, and freeze-drying to obtain the acrylate prepolymer; the inert gas is nitrogen; the chain transfer agent is 2-(dodecylthiocarbonylthio)-2-methylpropionic acid; the initiator is azobisisobutyronitrile; the emulsifier is emulsifier OP-10; the mass ratio of isooctyl acrylate, initiator, chain transfer agent, emulsifier, deionized water, styrene, hydroxyethyl acrylate, and itaconic acid is 50:0.1:0.1:3:100:15:5:5; and the photoinitiator is benzoin ethyl ether. GPC analysis showed that the acrylic prepolymer had Mn = 5000Da, M W / M n =1.15.

[0028] The aziridine crosslinking agent is aziridine crosslinking agent XR-100; the particle size of the graphene quantum dots is 3-5 nm; the coupling agent is silane coupling agent KH550; and the diluent is butyl acrylate.

[0029] A method for preparing the optical OCA adhesive comprises the following steps: uniformly mixing the raw materials, vacuum degassing, and uniformly coating the mixture on a PET release film using a slit coater, curing the mixture with UV light for 15 minutes, and then drying the mixture in hot air at 80°C for 4 minutes to obtain the optical OCA adhesive; the UV curing energy is 500mJ / cm².

[0030] An application of the optical OCA glue in a folding screen of a mobile phone includes the following steps: laminating the prepared optical OCA glue between the display panel and the cover plate of the folding screen, and laminating them through a hot pressing process, with a hot pressing temperature of 60°C, a pressure of 0.5 MPa, and a time of 1 minute.

[0031] Example 2 An optical OCA adhesive is prepared from the following raw materials in parts by weight: 50 parts of an acrylate prepolymer, 2.5 parts of 3-allyl-2-mercapto-3H-quinazolin-4-one, 1.5 parts of diallyl disulfide, 3.5 parts of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt, 1.5 parts of allyl succinimidyl carbonate, 2.5 parts of dicyclopentene methacrylate, 1.5 parts of 1,3,5-triacryloylhexahydro-1,3,5-triazine, 0.9 parts of a photoinitiator, 1.5 parts of an aziridine crosslinker, 1.5 parts of graphene quantum dots, 0.9 parts of a coupling agent, and 43 parts of a diluent.

[0032] The preparation method of the acrylic ester prepolymer comprises the following steps: under the protection of an inert gas atmosphere, adding isooctyl acrylate, an initiator, a chain transfer agent, an emulsifier, and deionized water into a reactor, stirring and reacting at a constant temperature of 69° C. for 3.5 hours, then dripping a mixed solution of styrene, hydroxyethyl acrylate, and itaconic acid into the reactor, completing the dripping within 1 hour, heating the mixture to 79° C. after completion of the dripping, continuing to stir and react at this temperature for 3.5 hours, cooling, dialyzing, and freeze-drying to obtain the acrylic ester prepolymer; the inert gas is helium; the chain transfer agent is 2-(dodecylthiocarbonylthio)-2-methylpropionic acid; the initiator is azobisisobutyronitrile; the emulsifier is emulsifier OP-10; and the mass ratio of the isooctyl acrylate, initiator, chain transfer agent, emulsifier, deionized water, styrene, hydroxyethyl acrylate, and itaconic acid is 50:0.1:0.1:3:100:15:5:5.

[0033] The photoinitiator is benzoin ethyl ether; the aziridine crosslinker is aziridine crosslinker XR-100; the particle size of the graphene quantum dots is 3-5 nm; the coupling agent is silane coupling agent KH560; and the diluent is hydroxyethyl methacrylate.

[0034] A method for preparing the optical OCA adhesive comprises the following steps: uniformly mixing the raw materials, vacuum degassing, and uniformly coating the mixture on a PET release film using a slit coater, curing the mixture with UV light for 16 minutes, and then drying the mixture in hot air at 80°C for 4.5 minutes to obtain the optical OCA adhesive; the UV curing energy is 600mJ / cm².

[0035] An application of the optical OCA glue in a folding screen of a mobile phone includes the following steps: laminating the prepared optical OCA glue between the display panel and the cover plate of the folding screen, and laminating them through a hot pressing process, with a hot pressing temperature of 65°C, a pressure of 0.6 MPa, and a time of 1.2 minutes.

[0036] Example 3 An optical OCA adhesive is prepared from the following raw materials in parts by weight: 50 parts of an acrylate prepolymer, 3 parts of 3-allyl-2-mercapto-3H-quinazolin-4-one, 2 parts of diallyl disulfide, 4 parts of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt, 2 parts of allyl succinimidyl carbonate, 3 parts of dicyclopentene methacrylate, 2 parts of 1,3,5-triacryloylhexahydro-1,3,5-triazine, 1 part of a photoinitiator, 2 parts of an aziridine crosslinker, 2 parts of graphene quantum dots, 1 part of a coupling agent, and 45 parts of a diluent.

[0037] The preparation method of the acrylic ester prepolymer comprises the following steps: under the protection of an inert gas atmosphere, adding isooctyl acrylate, an initiator, a chain transfer agent, an emulsifier, and deionized water into a reactor, stirring and reacting at a constant temperature of 70° C. for 4 hours, then dripping a mixed solution of styrene, hydroxyethyl acrylate, and itaconic acid into the reactor, completing the dripping within 1 hour, heating the mixture to 80° C. after completion of the dripping, continuing to stir and react at this temperature for 4 hours, cooling, dialyzing, and freeze-drying to obtain the acrylic ester prepolymer; the inert gas is neon; the chain transfer agent is 2-(dodecylthiocarbonylthio)-2-methylpropionic acid; the initiator is azobisisobutyronitrile; the emulsifier is emulsifier OP-10; and the mass ratio of the isooctyl acrylate, initiator, chain transfer agent, emulsifier, deionized water, styrene, hydroxyethyl acrylate, and itaconic acid is 50:0.1:0.1:3:100:15:5:5.

[0038] The photoinitiator is benzoin ethyl ether; the aziridine crosslinker is aziridine crosslinker XR-100; the particle size of the graphene quantum dots is 3-5 nm; the coupling agent is silane coupling agent KH570; and the diluent is isobornyl acrylate.

[0039] A method for preparing the optical OCA adhesive comprises the following steps: uniformly mixing the raw materials, vacuum degassing, and uniformly coating the mixture on a PET release film using a slit coater, curing the mixture with UV light for 17 minutes, and then drying the mixture in hot air at 80°C for 5 minutes to obtain the optical OCA adhesive; the UV curing energy is 650mJ / cm².

[0040] An application of the optical OCA glue in a folding screen of a mobile phone includes the following steps: laminating the prepared optical OCA glue between the display panel and the cover plate of the folding screen, and laminating them through a hot pressing process, with a hot pressing temperature of 70°C, a pressure of 0.7 MPa, and a time of 1.5 minutes.

[0041] Example 4 An optical OCA adhesive is prepared from the following raw materials in parts by weight: 50 parts of an acrylate prepolymer, 3.5 parts of 3-allyl-2-mercapto-3H-quinazolin-4-one, 2.5 parts of diallyl disulfide, 4.5 parts of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt, 2.5 parts of allyl succinimidyl carbonate, 3.5 parts of dicyclopentene methacrylate, 2.5 parts of 1,3,5-triacryloylhexahydro-1,3,5-triazine, 1.1 parts of a photoinitiator, 2.5 parts of an aziridine crosslinker, 2.5 parts of graphene quantum dots, 1.1 parts of a coupling agent, and 48 parts of a diluent.

[0042] The preparation method of the acrylic ester prepolymer comprises the following steps: under the protection of an inert gas atmosphere, adding isooctyl acrylate, an initiator, a chain transfer agent, an emulsifier, and deionized water into a reactor, stirring and reacting at a constant temperature of 71° C. for 4.5 hours, then dripping a mixed solution of styrene, hydroxyethyl acrylate, and itaconic acid into the reactor, completing the dripping within 1 hour, heating the mixture to 81° C. after completion of the dripping, continuing to stir and react at this temperature for 4.5 hours, cooling, dialyzing, and freeze-drying to obtain the acrylic ester prepolymer; the inert gas is argon; the chain transfer agent is 2-(dodecylthiocarbonylthio)-2-methylpropionic acid; the initiator is azobisisobutyronitrile; the emulsifier is emulsifier OP-10; and the mass ratio of the isooctyl acrylate, initiator, chain transfer agent, emulsifier, deionized water, styrene, hydroxyethyl acrylate, and itaconic acid is 50:0.1:0.1:3:100:15:5:5.

[0043] The photoinitiator is benzoin ethyl ether; the aziridine crosslinker is aziridine crosslinker XR-100; the particle size of the graphene quantum dots is 3-5 nm; the coupling agent is a mixture of silane coupling agent KH550, silane coupling agent KH560, and silane coupling agent KH570 in a mass ratio of 1:2:1; and the diluent is a mixture of butyl acrylate, hydroxyethyl methacrylate, isobornyl acrylate, and tetrahydrofurfuryl acrylic acid in a mass ratio of 1:2:1:2.

[0044] A method for preparing the optical OCA adhesive comprises the following steps: uniformly mixing the raw materials, vacuum degassing, uniformly coating the mixture on a PET release film using a slit coater, curing the mixture with UV light for 19 minutes, and then drying the mixture in hot air at 80°C for 5.5 minutes to obtain the optical OCA adhesive; the UV curing energy is 750mJ / cm².

[0045] An application of the optical OCA glue in a folding screen of a mobile phone includes the following steps: laminating the prepared optical OCA glue between the display panel and the cover plate of the folding screen, and laminating them through a hot pressing process, with a hot pressing temperature of 75°C, a pressure of 0.9 MPa, and a time of 1.8 minutes.

[0046] Example 5 An optical OCA adhesive is prepared from the following raw materials in parts by weight: 50 parts of an acrylate prepolymer, 4 parts of 3-allyl-2-mercapto-3H-quinazolin-4-one, 3 parts of diallyl disulfide, 5 parts of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt, 3 parts of allyl succinimidyl carbonate, 4 parts of dicyclopentene methacrylate, 3 parts of 1,3,5-triacryloylhexahydro-1,3,5-triazine, 1.2 parts of a photoinitiator, 3 parts of an aziridine crosslinker, 3 parts of graphene quantum dots, 1.2 parts of a coupling agent, and 50 parts of a diluent.

[0047] The preparation method of the acrylic ester prepolymer comprises the following steps: under the protection of an inert gas atmosphere, adding isooctyl acrylate, an initiator, a chain transfer agent, an emulsifier, and deionized water into a reactor, stirring and reacting at a constant temperature of 72° C. for 5 hours, then dripping a mixed solution of styrene, hydroxyethyl acrylate, and itaconic acid into the reactor, completing the dripping within 1 hour, heating the mixture to 82° C. after completion of the dripping, continuing to stir and react at this temperature for 5 hours, cooling, dialyzing, and freeze-drying to obtain the acrylic ester prepolymer; the inert gas is nitrogen; the chain transfer agent is 2-(dodecylthiocarbonylthio)-2-methylpropionic acid; the initiator is azobisisobutyronitrile; the emulsifier is emulsifier OP-10; and the mass ratio of the isooctyl acrylate, initiator, chain transfer agent, emulsifier, deionized water, styrene, hydroxyethyl acrylate, and itaconic acid is 50:0.1:0.1:3:100:15:5:5.

[0048] The photoinitiator is benzoin ethyl ether; the aziridine crosslinker is aziridine crosslinker XR-100; the particle size of the graphene quantum dots is 3-5 nm; the coupling agent is silane coupling agent KH560; and the diluent is tetrahydrofurfuryl acrylic acid.

[0049] A method for preparing the optical OCA adhesive comprises the following steps: uniformly mixing the raw materials, vacuum degassing, and uniformly coating the mixture on a PET release film using a slit coater, curing the mixture with UV light for 20 minutes, and then drying the mixture in hot air at 80°C for 6 minutes to obtain the optical OCA adhesive; the UV curing energy is 800mJ / cm².

[0050] An application of the optical OCA glue in a folding screen of a mobile phone includes the following steps: laminating the prepared optical OCA glue between the display panel and the cover plate of the folding screen, and laminating them through a hot pressing process, with a hot pressing temperature of 80°C, a pressure of 1 MPa, and a time of 2 minutes.

[0051] Comparative Example 1 This example provides a preparation method of optical OCA glue and its application in mobile phone folding screens, which is basically the same as Example 1, except that 3-allyl-2-mercapto-3H-quinazoline-4-one and diallyl disulfide are not added.

[0052] Comparative Example 2 This example provides a preparation method of optical OCA glue and its application in mobile phone folding screens, which is basically the same as Example 1, except that 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid salt and dicyclopentene methacrylate are not added.

[0053] The optical OCA adhesives involved in Examples 1-5 and Comparative Examples 1-2 were subjected to relevant performance tests. The test results are shown in Table 1. The thickness of each adhesive film of the test samples was controlled to be 50 μm. The test method is as follows: (1) Light transmittance: Refer to GB / T 2410-2008 for light transmittance test; (2) Peel strength: Refer to GB / T 2792-2014 to test the 180° peel strength between the stainless steel plate.

[0054] (3) Folding resistance: A folding test machine is used to test folding screen samples with OCA adhesive. The folding angle is 180° and the folding speed is 30 times / minute. After folding 300,000 times, the OCA adhesive layer is observed to see if cracks or delamination occur, and whether the touch function is normal. If there are no cracks or delamination in the adhesive layer and the touch function is normal, the folding resistance performance passes. Otherwise, it fails.

[0055] (4) Weather resistance test: Place the OCA glue sample in an environment of 85℃ / 85%RH. After 1000 hours, test and calculate the peel strength retention rate of the sample. The larger the value, the better the weather resistance.

[0056] Table 1 As can be seen from Table 1, the optical OCA glue involved in each embodiment of the present invention has higher bonding performance, light transmittance, weather resistance and folding resistance than the comparative example product. The combined use of 3-allyl-2-mercapto-3H-quinazolin-4-one, diallyl disulfide, 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid salt and dicyclopentene methacrylate is beneficial to improving the above properties.

[0057] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. An optical OCA adhesive, characterized in that: The invention comprises the following raw materials in parts by weight: 50 parts of acrylate prepolymer, 2-4 parts of 3-allyl-2-mercapto-3H-quinazolin-4-one, 1-3 parts of diallyl disulfide, 3-5 parts of 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt, 1-3 parts of allyl succinimidyl carbonate, 2-4 parts of dicyclopentene methacrylate, 1-3 parts of 1,3,5-triacryloylhexahydro-1,3,5-triazine, 0.8-1.2 parts of photoinitiator, 1-3 parts of aziridine crosslinking agent, 1-3 parts of graphene quantum dots, 0.8-1.2 parts of coupling agent, and 40-50 parts of diluent.

2. The optical OCA adhesive according to claim 1, characterized in that: The preparation method of the acrylic ester prepolymer comprises the following steps: under the protection of an inert gas atmosphere, adding isooctyl acrylate, an initiator, a chain transfer agent, an emulsifier, and deionized water into a reaction kettle, stirring and reacting at a constant temperature of 68-72° C. for 3-5 hours, then dripping a mixed solution of styrene, hydroxyethyl acrylate, and itaconic acid into the reaction kettle, and completing the dripping within 1 hour. After the dripping is completed, heating the mixture to 78-82° C., continuing to stir and react at the same temperature for 3-5 hours, cooling, dialyzing, and freeze-drying to obtain the acrylic ester prepolymer.

3. The optical OCA adhesive according to claim 2, characterized in that: The inert gas is any one of nitrogen, helium, neon and argon; and the chain transfer agent is 2-(dodecylthiocarbonylthio)-2-methylpropionic acid.

4. The optical OCA adhesive according to claim 2, characterized in that: The initiator is azobisisobutyronitrile; the emulsifier is emulsifier OP-10; the mass ratio of isooctyl acrylate, initiator, chain transfer agent, emulsifier, deionized water, styrene, hydroxyethyl acrylate, and itaconic acid is 50:0.1:0.1:3:100:15:5:

5.

5. The optical OCA adhesive according to claim 1, characterized in that: The photoinitiator is benzoin ethyl ether; the aziridine crosslinker is aziridine crosslinker XR-100.

6. The optical OCA adhesive according to claim 1, characterized in that: The particle size of the graphene quantum dots is 3-5 nm; the coupling agent is at least one of silane coupling agent KH550, silane coupling agent KH560, and silane coupling agent KH570.

7. The optical OCA adhesive according to claim 1, characterized in that: The diluent is at least one of butyl acrylate, hydroxyethyl methacrylate, isobornyl acrylate, and tetrahydrofurfuryl acrylic acid.

8. A method for preparing an optical OCA adhesive according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: uniformly mixing the raw materials, vacuum degassing, uniformly coating the raw materials on a PET release film through a slit coater, curing the film with ultraviolet light for 15-20 minutes, and then drying the film in hot air at 80°C for 4-6 minutes to obtain an optical OCA adhesive.

9. The method for preparing the optical OCA adhesive according to claim 8, characterized in that: The UV curing energy is 500-800mJ / cm².

10. Application of the optical OCA adhesive according to any one of claims 1 to 7 in a mobile phone folding screen, characterized in that: The method comprises the following steps: laminating the prepared optical OCA glue between the display panel and the cover plate of the folding screen, and laminating them through a hot pressing process, with a hot pressing temperature of 60-80°C, a pressure of 0.5-1MPa, and a time of 1-2 minutes.

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