Optical adhesive, preparation method, display module and device

Abstract

The invention discloses an optical adhesive, a preparation method, a display module and a display device, the optical adhesive comprises an acrylate polymer, and the acrylate polymer comprises at least one of a compound 1 and a compound 2. The viscosity of the optical adhesive can be reduced under ultraviolet irradiation, and accurate viscosity reduction can be achieved under ultraviolet irradiation. In the using process, the display screen and the cover plate can be bonded through the optical cement, and when the display screen and the cover plate need to be separated, the optical cement material can be irradiated through ultraviolet rays, so that the bonding force of the optical cement is remarkably reduced, the display screen and the cover plate are conveniently separated, the cover plate is conveniently reworked, maintained and replaced, and the maintenance difficulty and cost are greatly reduced.

Description

Technical Field

[0001] The present invention belongs to the field of display technology, and in particular relates to an optical adhesive, a preparation method, a display module and a device. Background Art

[0002] Smart devices are being used more and more widely, and display screens have become an important component of smart devices. With the rapid development of flexible folding screen technology, the demand for key component transparent optical adhesive (OCA) materials has become increasingly stringent. In terms of ultraviolet light (UV) viscosity reduction, traditional optical adhesives are often difficult to adjust or reprocess after curing. During the processing of the module structure, once the optical adhesive is poorly bonded and bubbles or uneven adhesion occurs, the entire screen often needs to be scrapped, which not only increases production costs, but also causes a waste of resources. In addition, folding screen devices may encounter various unexpected situations during use, such as falling, impact, etc., which may cause damage to the screen cover, make rework complicated, and take a long time, limiting the flexibility of the folding screen during processing and repair. Summary of the invention

[0003] The purpose of the embodiments of the present invention is to provide an optical adhesive, a preparation method, a display module and a device to solve the problem that the optical adhesive has a poor viscosity reduction effect.

[0004] In a first aspect, an embodiment of the present invention provides an optical adhesive, comprising:

[0005] An acrylate polymer, wherein the acrylate polymer comprises: at least one of Compound 1 and Compound 2;

[0006] The structural formula of compound 1 is:

[0007]

[0008] The structural formula of compound 2 is:

[0009]

[0010] Wherein, a, b, c, d and e are integers greater than 1.

[0011] Optionally, the weight average molecular weight of compound 1 and compound 2 are both 1-2 million.

[0012] In a second aspect, an embodiment of the present invention provides a method for preparing an optical adhesive, comprising:

[0013] Adding an acrylic acid ester monomer, an acrylic acid benzophenone derivative and a solvent into a reactor and mixing, introducing an inert gas and raising the temperature to 60-70° C., adding an initiator into the reactor and reacting for 3-5 hours, then raising the reaction temperature to 70-85° C. and reacting for 1.5-4 hours, cooling after the reaction is completed, and treating the product at 55-65° C. for 9-15 hours to obtain an acrylic acid ester polymer;

[0014] Among them, the acrylic acid ester monomers include: 2-ethylhexyl acrylate (2-EHA), n-hexyl acrylate (HA), butyl acrylate (BA), acrylic acid (AA);

[0015] The acrylic acid benzophenone derivative includes at least one of compound E1 and compound E2, and the structural formulas of compound E1 and compound E2 are:

[0016]

[0017] Optionally, the molar ratio of 2-ethylhexyl acrylate, n-hexyl acrylate, butyl acrylate and acrylic acid is (0.3-0.5):(0.1-0.3):(0.1-0.3):(0.05-0.15).

[0018] Optionally, the mass of the acrylic acid benzophenone derivative is 2-6% of the sum of the mass of the acrylic acid ester monomer and the acrylic acid benzophenone derivative.

[0019] Optionally, the solvent includes at least one of ethyl acetate, dimethylformamide, toluene, xylene, and dimethyl sulfoxide; and / or

[0020] The initiator comprises azobisisobutyronitrile; and / or

[0021] The mass of the initiator is 0.2-0.8% of the mass of the acrylic ester monomer.

[0022] Optionally, the step of treating the product at 55-65° C. for 9-15 hours after cooling comprises:

[0023] After cooling, the product was placed in a vacuum environment and treated at 55-65°C for 9-15h.

[0024] In a third aspect, an embodiment of the present invention provides a display module, including:

[0025] A display screen and a cover plate, wherein the display screen and the cover plate are connected via an adhesive layer, and the adhesive layer comprises optical glue;

[0026] The optical adhesive is the optical adhesive described in the above embodiment, or the optical adhesive prepared by the preparation method described in the above embodiment.

[0027] Optionally, the bonding layer is an optical adhesive layer, and the thickness of the optical adhesive layer is 30-70 um.

[0028] In a fourth aspect, an embodiment of the present invention provides a method for reworking a display module, comprising:

[0029] Using ultraviolet light to irradiate the adhesive layer in the display module to be reworked, and peel off the cover plate;

[0030] The display module is the display module described in the above embodiment.

[0031] Optionally, the wavelength of the ultraviolet light is 360nm-460nm, and the intensity is 2000-4200mJ / cm -1 , the irradiation time is 3-5min.

[0032] In a fifth aspect, an embodiment of the present invention provides a display device, including:

[0033] The display module described in the above embodiments.

[0034] The optical adhesive of the embodiment of the present invention includes: an acrylate polymer, and the acrylate polymer includes: at least one of compound 1 and compound 2. The optical adhesive of the present invention can reduce viscosity under ultraviolet light irradiation, and can achieve precise viscosity reduction under ultraviolet light irradiation. During use, the display screen and the cover plate can be bonded by the optical adhesive. When the display screen and the cover plate need to be separated, the optical adhesive material can be irradiated with ultraviolet rays to significantly reduce the adhesion of the optical adhesive, thereby facilitating the separation of the display screen and the cover plate, facilitating the rework and repair and replacement of the cover plate, and greatly reducing the difficulty and cost of repair. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a structural schematic diagram of a display module according to an embodiment of the present invention;

[0036] Figure 2 is a schematic structural diagram of an adhesive film;

[0037] Figure 3 A schematic diagram of a separation film layer after the optical adhesive in the adhesive film is reduced in viscosity;

[0038] Figure 4 is another structural schematic diagram of a display module according to an embodiment of the present invention;

[0039] Figure 5 A schematic diagram of the cross-linking of optical adhesive after ultraviolet light irradiation.

[0040] Reference numerals

[0041] Display screen 10; Cover plate 20;

[0042] Adhesive layer 30;

[0043] Support layer 40; Adhesive material layer 41;

[0044] A first cover plate 21; a second cover plate 22;

[0045] A first optical adhesive layer 31; a second optical adhesive layer 32; a second optical adhesive layer 32;

[0046] Upper protective film 61; Lower protective film 62. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] The terms "first", "second", etc. in the specification and claims of the present invention are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the terms used in this way are interchangeable under appropriate circumstances, so that the embodiments of the present invention can be implemented in an order other than those illustrated or described herein. In addition, the term "and / or" in the specification and claims means at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0049] The optical adhesive of the embodiment of the present invention comprises: an acrylate polymer, wherein the acrylate polymer comprises: at least one of compound 1 and compound 2;

[0050] The structural formula of compound 1 is:

[0051]

[0052] The structural formula of compound 2 is:

[0053]

[0054] Wherein, a, b, c, d and e are integers greater than 1.

[0055] The optical adhesive of the embodiment of the present invention can reduce viscosity under ultraviolet (UV) irradiation by adding benzophenone derivatives to the polymer network, thereby achieving rapid debonding under ultraviolet irradiation. During use, the display screen and the cover plate can be bonded by optical adhesive. When the display screen and the cover plate need to be separated, the optical adhesive material can be irradiated with ultraviolet rays to significantly reduce the adhesion of the optical adhesive, significantly reduce the peel strength between the display screen and the cover plate, and achieve peeling without residue without damaging the display screen, which is convenient for separating the display screen and the cover plate, and easy for rework, repair and replacement of the cover plate, greatly reducing the difficulty and cost of maintenance, which not only optimizes the separation process, reduces the complexity and difficulty of operation, but also greatly improves the flexibility and efficiency of the production line. Helps display manufacturing reduce costs and increase efficiency.

[0056] In some embodiments, the weight average molecular weight of compound 1 and compound 2 may both be 1-2 million. For example, the weight average molecular weight of compound 1 may be 1.2 million, and the weight average molecular weight of compound 2 may be 1.5 million.

[0057] The method for preparing the optical adhesive according to the embodiment of the present invention comprises:

[0058] Adding an acrylic acid ester monomer, an acrylic acid benzophenone derivative and a solvent into a reactor and mixing, introducing an inert gas and raising the temperature to 60-70° C., adding an initiator into the reactor and reacting for 3-5 hours, then raising the reaction temperature to 70-85° C. and reacting for 1.5-4 hours, cooling after the reaction is completed, and treating the product at 55-65° C. for 9-15 hours to obtain an acrylic acid ester polymer;

[0059] Among them, the acrylic acid ester monomers include: 2-ethylhexyl acrylate (2-EHA), n-hexyl acrylate (HA), butyl acrylate (BA), acrylic acid (AA);

[0060] The acrylic acid benzophenone derivative includes at least one of compound E1 and compound E2, and the structural formulas of compound E1 and compound E2 are:

[0061]

[0062]

[0063] When the acrylic acid benzophenone derivative is compound E1, the polymerization process of the acrylic acid ester polymer can be shown as formula (1), which is:

[0064]

[0065] When the acrylic acid benzophenone derivative is compound E2, the polymerization process of the acrylic acid ester polymer can be shown as formula (2), which is:

[0066]

[0067] For example, in the preparation process of optical adhesive, acrylate monomers, acrylic acid benzophenone derivatives and solvents can be added to a reactor and mixed, and the temperature is raised to 65°C after nitrogen gas is introduced, an initiator is added to the reactor and reacted for 4 hours, and then the reaction temperature is raised to 75°C for 3 hours. After the reaction is completed, the temperature is cooled, and the product can be placed in a vacuum at 60°C for 12 hours to obtain an acrylate polymer; wherein the acrylate monomers may include: 2-ethylhexyl acrylate (2-EHA), n-hexyl acrylate (HA), butyl acrylate (BA), acrylic acid (AA), the acrylic acid benzophenone derivative is compound E1 or compound E2, the molar ratio of 2-ethylhexyl acrylate, n-hexyl acrylate, butyl acrylate, and acrylic acid can be 0.5:0.2:0.2:0.1, and the mass of the acrylic acid benzophenone derivative can be 4% of the sum of the masses of the acrylate monomers and the acrylic acid benzophenone derivative. Acrylate monomers are introduced into the HA / BA short straight chain system. The introduction of short straight chain acrylate monomers has the ability of rapid molecular disentanglement, which helps to improve the creep recovery performance of optical adhesives. During the dynamic bending process of high temperature and high humidity, the flexible display device can effectively reduce the risk of cohesive failure of the optical adhesive layer and improve the problem of excessive creases on the flexible screen after repeated bending of the display device. The optical adhesive achieves UV viscosity reduction characteristics under the premise of folding reliability.

[0068] In some embodiments, the molar ratio of 2-ethylhexyl acrylate, n-hexyl acrylate, butyl acrylate, and acrylic acid can be (0.3-0.5): (0.1-0.3): (0.1-0.3): (0.05-0.15). For example, the molar ratio of 2-ethylhexyl acrylate, n-hexyl acrylate, butyl acrylate, and acrylic acid can be 0.3: 0.3: 0.3: 0.1, and the molar ratio of 2-ethylhexyl acrylate, n-hexyl acrylate, butyl acrylate, and acrylic acid can be 0.5: 0.2: 0.2: 0.1. The specific molar ratio can be selected according to actual conditions.

[0069] In other embodiments, the mass of the acrylic acid benzophenone derivative may be 2-6% of the sum of the mass of the acrylic acid ester monomer and the acrylic acid benzophenone derivative. For example, the mass of the acrylic acid benzophenone derivative may be 2%, 4% or 6% of the sum of the mass of the acrylic acid ester monomer and the acrylic acid benzophenone derivative, and the specific mass may be selected according to actual conditions.

[0070] In an embodiment of the present invention, the solvent may include at least one of ethyl acetate, dimethylformamide, toluene, xylene, and dimethyl sulfoxide. For example, the solvent may be ethyl acetate, xylene or dimethylformamide. The solvent may include toluene and xylene. The specific type and amount of the solvent may be selected according to actual conditions.

[0071] The initiator may include azobisisobutyronitrile, and the mass of the initiator may be 0.2-0.8% of the mass of the acrylate monomer. For example, the mass of the initiator may be 0.2%, 0.4%, 0.6% or 0.8% of the mass of the acrylate monomer. The specific type and amount of the initiator may be selected according to actual conditions.

[0072] In some embodiments, the step of treating the product at 55-65° C. for 9-15 hours after cooling may include:

[0073] After cooling, the product is placed in a vacuum environment and treated at 55-65°C for 9-15 hours. For example, after cooling, the product is placed in a vacuum environment and treated at 55°C for 15 hours, or after cooling, the product is placed in a vacuum environment and treated at 65°C for 9 hours. The specific temperature and time can be selected according to the actual situation.

[0074] like Figure 1 As shown, the display module of the embodiment of the present invention includes:

[0075] A display screen 10 and a cover plate 20, wherein the display screen 10 and the cover plate 20 are connected via an adhesive layer 30, and the adhesive layer 30 may include optical glue;

[0076] The optical adhesive is the optical adhesive described in the above embodiment, or the optical adhesive prepared by the preparation method described in the above embodiment.

[0077] The display screen 10 and the cover plate 20 can be bonded together by the adhesive layer 30. When the cover plate 20 is poorly bonded and bubbles or unevenly bonded, or when the cover plate is damaged and needs to be repaired or replaced, the viscosity can be reduced under ultraviolet light. During use, the display screen and the cover plate can be bonded by optical glue. When the display screen and the cover plate need to be separated, the optical adhesive layer material can be irradiated with ultraviolet light to reduce the adhesion of the optical adhesive layer, making it easier to separate the display screen and the cover plate, and to rework, repair and replace the cover plate, greatly reducing the difficulty and cost of repair, and improving the flexibility of the folding screen during processing and repair.

[0078] Optionally, the adhesive layer may be an optical adhesive layer, and the thickness of the optical adhesive layer may be 30-70 um. For example, the thickness of the optical adhesive layer may be 30, 40, 50, 60 or 70 um. The specific thickness may be adjusted and selected according to actual use.

[0079] The cover plate may be a flexible cover plate, such as Figure 4 As shown, the display module may further include: a support layer 40 and a glue layer 41, the glue layer 41 is arranged between the display screen 10 and the support layer 40, and the cover plate 20 is arranged on the side of the display screen 10 away from the support layer 40. The cover plate 20 may include a first cover plate 21 and a second cover plate 22, and the first cover plate 21 and the second cover plate 22 may be flexible cover plates. The first cover plate 21 may be arranged on the side of the display screen 10 away from the support layer 40, and the first cover plate 21 and the display screen 10 are bonded and connected by the first optical glue layer 31, and the second cover plate 22 may be arranged on the side of the first cover plate 21 away from the display screen 10, and the second cover plate 22 and the first cover plate 21 are bonded and connected by the second optical glue layer 32. A protective film 50 may be arranged on the side of the second cover plate 22 away from the display screen 10, and the protective film 50 and the second cover plate 22 may be bonded and connected by the third optical glue layer 33, and the first optical glue layer 31, the second optical glue layer 32, and the third optical glue layer 33 may all be optical glues in the present invention.

[0080] The display module reworking method according to an embodiment of the present invention comprises:

[0081] Using ultraviolet light to irradiate the adhesive layer in the display module to be reworked, and peel off the cover plate;

[0082] The display module is the display module described in the above embodiment.

[0083] In some embodiments of the present invention, the wavelength of the ultraviolet light may be 360nm-460nm, and the intensity may be 2000-4200mJ / cm -1 The irradiation time can be 3-5 minutes. Preferably, the wavelength of the ultraviolet light can be 385nm-420nm, for example, the wavelength of the ultraviolet light can be 380, and the intensity can be 3600mJ / cm -1 The irradiation time can be 4 minutes; the wavelength of the ultraviolet light can be 420, and the intensity can be 2000mJ / cm -1 The irradiation time can be 5 minutes, and the specific wavelength, intensity and irradiation time can be selected according to actual conditions.

[0084] A display device according to an embodiment of the present invention includes:

[0085] The display module described in the above embodiment. The display device having the display module described in the above embodiment is easy to rework and repair and replace, which reduces the difficulty and cost of repair and improves the flexibility in the processing and repair process.

[0086] like Figure 2 and Figure 3As shown, the material of the upper protective film 61 and the lower protective film 62 can be polyethylene terephthalate, and there is an adhesive layer 30 between the upper protective film 61 and the lower protective film 62, and the adhesive layer 30 is an optical adhesive layer. Figure 3 Schematic diagram of separation after viscosity reduction by ultraviolet (UV) irradiation. Figure 5 The cross-linking change process of benzophenone derivatives in optical adhesives under medium ultraviolet light irradiation. Under specific light wave ultraviolet light irradiation, the cross-linking change process of benzophenone derivatives in optical adhesives from the initial state to the response state: Initial benzophenone derivatives: This represents the state of benzophenone derivatives in the optical adhesive before being irradiated with UV light. At this time, they exist in the polymer network of the optical adhesive in some form, but no responsive changes have occurred. UV irradiation: When UV light is irradiated on the optical adhesive, it is absorbed by the benzophenone derivatives. Responsive benzophenone derivatives, after absorbing UV light, the benzophenone derivatives undergo chemical reactions, resulting in changes in their molecular structure or properties. Cross-linking changes: In the responsive state, benzophenone derivatives may initiate or participate in changes in the cross-linking structure in the adhesive polymer network. This change may include the breaking, rearrangement or formation of new cross-linking bonds, which ultimately leads to a decrease in the overall adhesion of the optical adhesive and a debonding effect.

[0087] By introducing UV-sensitive chemicals (such as benzophenone derivatives) into optical adhesives, these sensitive substances will undergo chemical reactions under UV light, causing changes in the cross-linking structure between optical adhesive molecules. The main mechanism is that post-crosslinking captures hydrogen atoms and destroys the cross-linking structure of the optical adhesive; second, post-crosslinking increases the degree of curing, causing the volume of the optical adhesive to shrink, thereby reducing its adhesion and achieving debonding. This monomer has low reactivity under visible light and active free radicals and does not affect the performance of the optical adhesive, but it can promote additional cross-linking through UV-induced reactions. The viscosity of the optical adhesive can be further reduced after UV light exposure by combining it with an organic solvent (ethanol, acetone, etc.).

[0088] The present invention is further described below through some specific embodiments.

[0089] Example 1

[0090] Adding an acrylate monomer, an acrylic acid benzophenone derivative and an ethyl acetate solvent into a reactor and mixing, introducing nitrogen gas and raising the temperature to 60° C., adding an initiator into the reactor and reacting for 5 hours, then raising the reaction temperature to 85° C. and reacting for 1.5 hours, cooling after the reaction is completed, and placing the product in a vacuum at 55° C. for 15 hours to obtain an acrylate polymer;

[0091] Wherein, the acrylic acid ester monomers include: 2-ethylhexyl acrylate (2-EHA), n-hexyl acrylate (HA), butyl acrylate (BA), acrylic acid (AA), the acrylic acid benzophenone derivative is compound E1, the molar ratio of 2-ethylhexyl acrylate, n-hexyl acrylate, butyl acrylate, and acrylic acid can be 3:3:1:0.5, and the mass of the acrylic acid benzophenone derivative can be 2% of the sum of the mass of the acrylic acid ester monomers and the acrylic acid benzophenone derivative;

[0092] The initiator is azobisisobutyronitrile, and the mass of the initiator is 0.2% of the mass of the acrylic ester monomer.

[0093] Example 2

[0094] Adding an acrylate monomer, an acrylic acid benzophenone derivative and an ethyl acetate solvent into a reactor and mixing, introducing nitrogen gas and raising the temperature to 70° C., adding an initiator into the reactor and reacting for 3 hours, then raising the reaction temperature to 70° C. and reacting for 4 hours, cooling down after the reaction is completed, and placing the product in a vacuum at 65° C. for 9 hours to obtain an acrylate polymer;

[0095] Wherein, the acrylic acid ester monomers include: 2-ethylhexyl acrylate (2-EHA), n-hexyl acrylate (HA), butyl acrylate (BA), acrylic acid (AA), the acrylic acid benzophenone derivative is compound E1, the molar ratio of 2-ethylhexyl acrylate, n-hexyl acrylate, butyl acrylate, and acrylic acid can be 3:1:3:1.5, and the mass of the acrylic acid benzophenone derivative can be 6% of the sum of the mass of the acrylic acid ester monomers and the acrylic acid benzophenone derivative;

[0096] The initiator is azobisisobutyronitrile, and the mass of the initiator is 0.8% of the mass of the acrylic ester monomer.

[0097] Example 3

[0098] Adding an acrylic acid ester monomer, an acrylic acid benzophenone derivative and an ethyl acetate solvent into a reactor and mixing, introducing nitrogen gas and raising the temperature to 65° C., adding an initiator into the reactor and reacting for 4 hours, then raising the reaction temperature to 75° C. and reacting for 3 hours, cooling down after the reaction is completed, and placing the product in a vacuum at 60° C. for 12 hours to obtain an acrylic acid ester polymer;

[0099] Wherein, the acrylate monomers include: 2-ethylhexyl acrylate (2-EHA), n-hexyl acrylate (HA), butyl acrylate (BA), acrylic acid (AA), the acrylic acid benzophenone derivative is compound E1, the molar ratio of 2-ethylhexyl acrylate, n-hexyl acrylate, butyl acrylate, and acrylic acid can be 5:2:2:1, and the mass of the acrylic acid benzophenone derivative is 2% of the sum of the mass of the acrylate monomers and the acrylic acid benzophenone derivative;

[0100] The initiator is azobisisobutyronitrile, and the mass of the initiator is 0.4% of the mass of the acrylic ester monomer.

[0101] Example 4

[0102] The difference between Example 4 and Example 3 is that:

[0103] The mass of the acrylic acid benzophenone derivative is 4% of the sum of the mass of the acrylic acid ester monomer and the acrylic acid benzophenone derivative.

[0104] Example 5

[0105] The difference between Example 5 and Example 3 is that:

[0106] The mass of the acrylic acid benzophenone derivative is 6% of the sum of the mass of the acrylic acid ester monomer and the acrylic acid benzophenone derivative.

[0107] Example 6

[0108] Adding an acrylate monomer, an acrylic acid benzophenone derivative and an ethyl acetate solvent into a reactor and mixing, introducing nitrogen gas and raising the temperature to 70°C, adding an initiator into the reactor and reacting for 3 hours, then raising the reaction temperature to 85°C and reacting for 1.5 hours, cooling after the reaction is completed, and placing the product in a vacuum at 65°C for 9 hours to obtain an acrylate polymer;

[0109] Wherein, the acrylate monomers include: 2-ethylhexyl acrylate (2-EHA), n-hexyl acrylate (HA), butyl acrylate (BA), acrylic acid (AA), the acrylic acid benzophenone derivative is compound E2, the molar ratio of 2-ethylhexyl acrylate, n-hexyl acrylate, butyl acrylate, and acrylic acid can be 3:3:1:1.5, and the mass of the acrylic acid benzophenone derivative can be 2% of the sum of the mass of the acrylate monomers and the acrylic acid benzophenone derivative;

[0110] The initiator is azobisisobutyronitrile, and the mass of the initiator is 0.2% of the mass of the acrylic ester monomer.

[0111] Example 7

[0112] Adding an acrylate monomer, an acrylic acid benzophenone derivative and an ethyl acetate solvent into a reactor and mixing, introducing nitrogen gas and raising the temperature to 60° C., adding an initiator into the reactor and reacting for 5 hours, then raising the reaction temperature to 85° C. and reacting for 2 hours, cooling after the reaction is completed, and placing the product in a vacuum at 60° C. for 15 hours to obtain an acrylate polymer;

[0113] Wherein, the acrylate monomers include: 2-ethylhexyl acrylate (2-EHA), n-hexyl acrylate (HA), butyl acrylate (BA), acrylic acid (AA), the acrylic acid benzophenone derivative is compound E2, the molar ratio of 2-ethylhexyl acrylate, n-hexyl acrylate, butyl acrylate, and acrylic acid can be 3:1:3:0.5, and the mass of the acrylic acid benzophenone derivative can be 6% of the sum of the mass of the acrylate monomers and the acrylic acid benzophenone derivative;

[0114] The initiator is azobisisobutyronitrile, and the mass of the initiator is 0.8% of the mass of the acrylic ester monomer.

[0115] Example 8

[0116] Adding an acrylate monomer, an acrylic acid benzophenone derivative and an ethyl acetate solvent into a reactor and mixing, introducing nitrogen gas and raising the temperature to 65° C., adding an initiator into the reactor and reacting for 4 hours, then raising the reaction temperature to 80° C. and reacting for 2.5 hours, cooling after the reaction is completed, and placing the product in a vacuum at 60° C. for 11 hours to obtain an acrylate polymer;

[0117] Wherein, the acrylic acid ester monomers include: 2-ethylhexyl acrylate (2-EHA), n-hexyl acrylate (HA), butyl acrylate (BA), acrylic acid (AA), the acrylic acid benzophenone derivative is compound E2, the molar ratio of 2-ethylhexyl acrylate, n-hexyl acrylate, butyl acrylate, and acrylic acid can be 5:2:2:1, and the mass of the acrylic acid benzophenone derivative is 4% of the sum of the mass of the acrylic acid ester monomers and the acrylic acid benzophenone derivative;

[0118] The initiator is azobisisobutyronitrile, and the mass of the initiator is 0.4% of the mass of the acrylic ester monomer.

[0119] Comparative Example 1

[0120] The difference between Comparative Example 1 and Example 3 is that:

[0121] The mass of the acrylic acid benzophenone derivative is 0% of the sum of the masses of the acrylic acid ester monomer and the acrylic acid benzophenone derivative.

[0122] Comparative Example 2

[0123] The difference between Comparative Example 2 and Example 8 is that:

[0124] The mass of the acrylic acid benzophenone derivative is 0% of the sum of the masses of the acrylic acid ester monomer and the acrylic acid benzophenone derivative.

[0125] The optical adhesives prepared in the embodiments and comparative examples were tested.

[0126] Mix the acrylic polymer and ethyl acetate solvent in a mass ratio of 1:1, take an appropriate amount of glue, apply it on the polyethylene terephthalate film, use a flat coater to coat it, and cure and dry it in an oven. The thickness of the dry glue layer is controlled to be about 50um. Take it out after 3 minutes, stick a release film, and cut it into standard sample size as required for testing.

[0127] The test results of the optical adhesives in the embodiments and comparative examples are shown in Table 1.

[0128] Table 1 Test results of optical adhesives in the embodiments and comparative examples

[0129]

[0130] As can be seen from Table 1, the viscosity of the optical adhesive prepared in the embodiment of the present invention is appropriate, and the viscosity can be reduced under ultraviolet (UV) irradiation, thereby achieving rapid debonding under ultraviolet irradiation. During use, the optical adhesive material can be irradiated with ultraviolet light to significantly reduce the adhesive force of the optical adhesive and reduce the peel strength between the display screen and the cover plate.

[0131] Reliability test of the optical adhesive in the embodiment and comparative example, dynamic bending: the test results of 200,000 U-bends at 25°C; static bending: the test results of 240 hours after U-bend at 25°C. The test results of the optical adhesive in the embodiment and comparative example are shown in Table 2.

[0132] Table 2 Reliability test results of optical adhesives in the embodiments and comparative examples

[0133]

[0134] It can be seen from Table 2 that the optical adhesive prepared in the embodiment of the present invention has good stability after bending and good reliability test, which can meet the needs.

[0135] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. An optical adhesive, characterized in that: include: An acrylate polymer, wherein the acrylate polymer comprises: at least one of Compound 1 and Compound 2; The structural formula of compound 1 is: The structural formula of compound 2 is: Wherein, a, b, c, d and e are integers greater than 1.

2. The optical adhesive according to claim 1, characterized in that: The weight average molecular weights of the compound 1 and the compound 2 are both 1-2 million.

3. A method for preparing an optical adhesive, characterized in that: include: Adding an acrylic acid ester monomer, an acrylic acid benzophenone derivative and a solvent into a reactor and mixing, introducing an inert gas and raising the temperature to 60-70° C., adding an initiator into the reactor and reacting for 3-5 hours, then raising the reaction temperature to 70-85° C. and reacting for 1.5-4 hours, cooling after the reaction is completed, and treating the product at 55-65° C. for 9-15 hours to obtain an acrylic acid ester polymer; Among them, the acrylic acid ester monomers include: 2-ethylhexyl acrylate, n-hexyl acrylate, butyl acrylate, acrylic acid; The acrylic acid benzophenone derivative includes at least one of compound E1 and compound E2, and the structural formulas of compound E1 and compound E2 are:

4. The preparation method according to claim 3, characterized in that: The molar ratio of 2-ethylhexyl acrylate, n-hexyl acrylate, butyl acrylate and acrylic acid is (0.3-0.5):(0.1-0.3):(0.1-0.3):(0.05-0.15).

5. The preparation method according to claim 3, characterized in that: The mass of the acrylic acid benzophenone derivative is 2-6% of the sum of the mass of the acrylic acid ester monomer and the acrylic acid benzophenone derivative.

6. The preparation method according to claim 3, characterized in that: The solvent comprises at least one of ethyl acetate, dimethylformamide, toluene, xylene and dimethyl sulfoxide; and / or The initiator comprises azobisisobutyronitrile; and / or The mass of the initiator is 0.2-0.8% of the mass of the acrylic ester monomer.

7. The preparation method according to claim 3, characterized in that: The step of treating the product at 55-65° C. for 9-15 hours after cooling comprises: After cooling, the product was placed in a vacuum environment and treated at 55-65°C for 9-15h.

8. A display module, characterized in that: include: A display screen and a cover plate, wherein the display screen and the cover plate are connected via an adhesive layer, and the adhesive layer comprises optical glue; The optical adhesive is the optical adhesive described in any one of claims 1-2, or the optical adhesive prepared by the preparation method described in any one of claims 3-7.

9. The display module according to claim 8, characterized in that: The bonding layer is an optical adhesive layer, and the thickness of the optical adhesive layer is 30-70 um.

10. A method for reworking a display module, characterized in that: include: Using ultraviolet light to irradiate the adhesive layer in the display module to be reworked, and peel off the cover plate; The display module is the display module according to any one of claims 8 to 9.

11. The reworking method according to claim 10, characterized in that: The wavelength of the ultraviolet light is 360nm-460nm, and the intensity is 2000-4200mJ / cm -1 , the irradiation time is 3-5min.

12. A display device, characterized in that: include: The display module according to any one of claims 8 to 9.

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