Optical adhesive and method of making and using same

Abstract

The present application relates to the technical field of optical glue, in particular to an optical glue, a preparation method and application thereof. The optical glue comprises an acrylic resin and a crosslinking agent; the amount of the crosslinking agent is 0.1wt%-0.5wt% of the acrylic resin; the acrylic resin is mainly prepared by copolymerization of acrylic ester monomers; the acrylic ester monomers comprise 5wt%-10wt% of an acrylic ester compound as shown in Formula I; wherein R1 is selected from alkylene with a carbon number of 1-3. In the optical glue of the present application, a certain amount of monomers with both F atoms and boric acid groups is introduced into the acrylic resin, which helps to improve the high-temperature resistance and weather resistance of the optical glue, and balance the peeling force, initial adhesion and cohesion of the optical glue, so as to meet the requirements of the optical glue for vehicle-mounted display.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical glue, in particular to an optical glue and a preparation method and application thereof. BACKGROUND

[0002] Optical glue (OCA) for vehicle display is a key material for automobile display screen (such as central control screen, instrument panel, HUD, etc.), which directly affects the display effect, touch sensitivity, durability and safety. After the optical glue for vehicle display is tested for temperature resistance (95℃×1000h) and weather resistance (85℃ / 85%×1000h), the optical glue is required to have no yellowing, back foaming, warping and other defects.

[0003] At present, the optical glue for vehicle display is mainly prepared by using solvent type acrylic resin and UV curing acrylic resin. However, the optical glue prepared by using acrylic resin has poor weather resistance and temperature resistance, and is prone to yellowing and back foaming.

[0004] Therefore, the present application is proposed. SUMMARY

[0005] The present application aims to provide an optical glue and a preparation method and application thereof. The optical glue has good temperature resistance and weather resistance, and has balanced three forces (peeling force, initial adhesion and cohesion).

[0006] In order to achieve the above-mentioned purpose of the present application, the first aspect of the present application provides an optical glue, which comprises an acrylic resin and a crosslinking agent; the amount of the crosslinking agent is 0.1wt%-0.5wt% of the acrylic resin.

[0007] The acrylic resin is mainly prepared by copolymerization of acrylic ester monomers; the acrylic ester monomers comprise 5wt%-10wt% of an acrylic ester compound as shown in Formula I.

[0008]

[0009] wherein R1 is selected from alkylene with carbon number of 1-3.

[0010] In the specific embodiment of the present application, the acrylic ester monomers comprise the following components by mass percentage: hard monomer 10%-20%, soft monomer 70%-80%, functional monomer 3%-5%, polar monomer 1%-2% and acrylic ester compound as shown in Formula I 5%-10%.

[0011] In the specific embodiment of the present application, the hard monomer comprises methyl acrylate and / or methyl methacrylate.

[0012] In the detailed description of the present application, the soft monomer includes butyl acrylate and / or isooctyl acrylate.

[0013] In the detailed description of the present application, the functional monomer is a hydroxyl-containing acrylate monomer. Further, the functional monomer includes at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate and hydroxypropyl methacrylate.

[0014] In the detailed description of the present application, the polar monomer includes acrylamide.

[0015] In the detailed description of the present application, the acrylate resin further includes an initiator and an organic solvent. Further, the amount of the initiator is 0.1wt% to 0.3wt% of the total amount of the acrylate monomers; and the amount of the organic solvent is 80wt% to 120wt% of the total amount of the acrylate monomers.

[0016] In the detailed description of the present application, the crosslinking agent is an isocyanate crosslinking agent.

[0017] The second aspect of the present application provides a preparation method of the optical adhesive of the first aspect of the present application, including the following steps: (a) proportionally mixing components to obtain a mixture; (b) coating the mixture on the surface of a release film, and after drying treatment, covering the release film to obtain the optical adhesive.

[0018] The third aspect of the present application provides an application of the optical adhesive of the first aspect of the present application in a vehicle-mounted display device.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] (1) In the optical adhesive of the present application, a certain amount of monomer with both F atom and boric acid group is introduced into the acrylate resin. The boric acid group dehydrates and condenses by itself under high temperature condition, not only forming a crosslinking network but also generating new crosslinking points, which helps to improve the high temperature resistance of the optical adhesive. Meanwhile, the introduction of F atom makes the acrylate resin have low surface energy, endowing the acrylate resin with excellent water resistance, and making the optical adhesive have excellent weather resistance.

[0021] (2) The optical adhesive of the present application has no yellowing, back foaming, warping and other defects after the temperature resistance test at 95℃×1000h and the weather resistance test of double 85×1000h, meeting the use requirements of vehicle-mounted display device. DETAILED DESCRIPTION

[0022] The technical solutions of the present application will be described clearly and completely in combination with specific embodiments below, but those skilled in the art will understand that the following described embodiments are part of the embodiments of the present application, not all the embodiments, and are only used to illustrate the present application, and should not be regarded as limiting the scope of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application. The specific conditions are not specified in the embodiments, and are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are not specified by the manufacturer, and are conventional products that can be purchased on the market.

[0023] Acrylic resin is one of the main resin matrices for preparing optical adhesive for vehicle display. However, the acrylic resin contains a large number of ester groups, carbonyl groups, hydroxyl groups and other groups, which are easy to form hydrogen bonds with water molecules; and the ester groups are prone to hydrolysis reaction under humid heat environment. The vehicle environment is exposed to high temperature and high humidity environment for a long time, which accelerates the penetration of water molecules, resulting in yellowing, back foaming, warping and other problems of the optical adhesive for vehicle display. Therefore, it is of great significance to develop an optical adhesive with good weather resistance for the development of vehicle display.

[0024] The present application provides an optical adhesive in the first aspect, comprising an acrylic resin and a crosslinking agent; the amount of the crosslinking agent is 0.1wt%-0.5wt% of the acrylic resin; the acrylic resin is mainly prepared by copolymerization of acrylic ester monomers; the acrylic ester monomers include 5wt%-10wt% of acrylic ester compounds as shown in formula I;

[0025]

[0026] wherein R1 is selected from alkylene groups with carbon number of 1-3.

[0027] In the optical adhesive of the present application, a certain amount of monomers with F atoms and boronic acid groups are introduced into the acrylic resin. The boronic acid groups dehydrate and condense under high temperature conditions, not only forming a crosslinking network but also generating new crosslinking points, which helps to improve the high temperature resistance of the optical adhesive. At the same time, the introduction of F atoms makes the acrylic resin have low surface energy, endowing the acrylic resin with excellent water resistance. After crosslinking reaction with the crosslinking agent, the optical adhesive has excellent high temperature resistance, weather resistance, and can ensure the balance of peel strength, initial tack and cohesion.

[0028] In the acrylic ester compound as shown in Formula I, R1may be at least one of methylene, ethylene or propylene. In different embodiments, the acrylic ester compound as shown in Formula I in the acrylic ester monomer can account for 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt% or a range formed by any two of them, for example, 6wt%~8wt% and the like. Research has found that when the acrylic ester compound as shown in Formula I in the acrylic ester monomer accounts for too low, the improvement of the weather resistance of the optical adhesive is not obvious; when the acrylic ester compound as shown in Formula I in the acrylic ester monomer accounts for too high, the three forces of the optical adhesive cannot be considered.

[0029] In different embodiments, the amount of crosslinking agent can be 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt% or a range formed by any two of them of the acrylic resin.

[0030] In the specific embodiments of the present application, the acrylic ester monomer includes the following components by mass percentage: hard monomer 10%~20%, soft monomer 70%~80%, functional monomer 3%~5%, polar monomer 1%~2% and acrylic ester compound as shown in Formula I 5%~10%. A certain amount of acrylic ester compound as shown in Formula I is introduced into the acrylic resin of the present application to improve the high temperature resistance and weather resistance of the optical adhesive, and at the same time, the amount of hard monomer, soft monomer, functional monomer and polar monomer is adjusted to meet the above conditions to further balance the three forces of the optical adhesive.

[0031] In different embodiments, the amount of each type of monomer in the acrylic ester monomer can be as follows by mass percentage:

[0032] The amount of hard monomer can be 10%, 12%, 15%, 18%, 20% or a range formed by any two of them;

[0033] The amount of soft monomer can be 70%, 72%, 75%, 78%, 80% or a range formed by any two of them;

[0034] The amount of functional monomer can be 3%, 3.5%, 4%, 4.5%, 5% or a range formed by any two of them;

[0035] The amount of polar monomer can be 1%, 1.2%, 1.5%, 1.8%, 2% or a range formed by any two of them;

[0036] The amount of acrylic ester compound as shown in Formula I can be 5%, 6%, 7%, 8%, 9%, 10% or a range formed by any two of them.

[0037] The acrylate compound shown as Formula I can be prepared according to the following route:

[0038]

[0039] Specifically, the compound A and the compound B are subjected to esterification under the action of a condensing agent (such as DCC and DMAP) to obtain the acrylate compound shown as Formula I. In the esterification reaction, the boronic acid has low reactivity and does not affect the esterification reaction process of forming the compound shown as Formula I.

[0040] In actual operation, the esterification reaction includes: after the compound A, the compound B and the DMAP are uniformly mixed and stirred, the DCC is added, and then the reaction is carried out at 10-30°C for 6-10h to obtain the acrylate compound shown as Formula I. Among them, the molar ratio of the compound A to the compound B can be 1:1, the molar ratio of the DMAP to the compound A is 0.1:1, and the molar ratio of the DCC to the compound A is 1.1:1. The specific reaction temperature and reaction time can be adjusted according to the reaction progress.

[0041] In the specific embodiment of the present application, the acrylate compound shown as Formula I has the following structural formula:

[0042]

[0043] When the structure of the acrylate compound shown as Formula I is as shown above, the structural formula of the corresponding compound B is as follows:

[0044]

[0045] In the specific embodiment of the present application, the hard monomer includes methyl acrylate and / or methyl methacrylate.

[0046] In the specific embodiment of the present application, the soft monomer includes butyl acrylate and / or isooctyl acrylate.

[0047] In the specific embodiment of the present application, the functional monomer is a hydroxyl-containing acrylate monomer. Further, the functional monomer includes at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate and hydroxypropyl methacrylate.

[0048] In the specific embodiment of the present application, the polar monomer includes acrylamide. The introduction of an appropriate amount of acrylamide in the acrylate resin of the present application is more helpful to improve the initial adhesion of the optical glue.

[0049] In the specific embodiments of the present application, the acrylic resin further comprises an initiator and an organic solvent. Further, the initiator is used in an amount of 0.1wt% to 0.3wt% of the total amount of the acrylic monomers, for example, 0.1wt%, 0.15wt%, 0.2wt%, 0.25wt%, 0.3wt% or a range between any two of them; and the organic solvent is used in an amount of 80wt% to 120wt% of the total amount of the acrylic monomers, for example, 80wt%, 90wt%, 100wt%, 110wt%, 120wt% or a range between any two of them.

[0050] In the specific embodiments of the present application, the initiator is at least one of peroxide initiator and azo initiator, and the specific type is not limited, as long as it can initiate the polymerization reaction of the acrylic monomers, for example, dibenzoyl peroxide, azobisisobutyronitrile, etc.; and the organic solvent includes, but is not limited to, at least one of ethyl acetate, toluene, xylene, butyl acetate.

[0051] In the specific embodiments of the present application, the preparation of the acrylic resin comprises: weighing the raw materials (acrylic monomers, initiator and solvent) in proportion, and reacting at 85-95℃ for 6-12h under a protective atmosphere. In the preparation of the acrylic resin, the protective atmosphere can be nitrogen, but is not limited thereto; the reaction temperature can be 85℃, 88℃, 90℃, 92℃, 95℃ or any value between any two of them, and the reaction time can be 6h, 8h, 10h, 12h, etc.

[0052] In the specific embodiments of the present application, the weight average molecular weight of the acrylic resin can exemplarily be 0.9-1.5 million, but is not limited thereto; and the molecular weight distribution width of the acrylic resin can exemplarily be 3.5-4.5, but is not limited thereto.

[0053] In the specific embodiments of the present application, the crosslinking agent is an isocyanate crosslinking agent. The isocyanate crosslinking agent can react with the hydroxyl group in the acrylic resin, etc., to achieve crosslinking. For example, in different embodiments, the isocyanate crosslinking agent is a multifunctional isocyanate crosslinking agent, including but not limited to any one or more of HDI trimer, TDI trimer, IPDI trimer.

[0054] In the specific embodiments of the present application, the optical adhesive further comprises a solvent. Further, the solvent includes at least one of ethyl acetate, toluene, xylene and butyl acetate.

[0055] The amount of solvent in the optical adhesive can be adjusted according to actual needs to ensure the coating requirements of the optical adhesive and the drying time requirements after coating. For example, the amount of solvent can be 5wt%-40wt% of the acrylic resin, such as 5wt%, 10wt%, 15wt%, 20wt%, 30wt%, 40wt%, etc., but is not limited thereto.

[0056] The second aspect of the present application provides a preparation method of the optical adhesive of the first aspect of the present application, comprising the following steps: (a) mixing the components in proportion to obtain a mixture; (b) coating the mixture on the surface of a release film, and after drying treatment, covering the release film to obtain the optical adhesive.

[0057] The coating thickness of the mixture can be adjusted according to the actual thickness requirements of the optical adhesive, such as controlling the thickness of the optical adhesive layer formed after the mixture is coated and dried to be 50-300μm, but is not limited thereto. The release film can include polyethylene terephthalate (PET) film, polyimide (PI) film, polyethylene (PE) film, oriented polypropylene (OPP) film, composite release film and the like. Since the release film will be removed in actual use, the thickness of the release film has less effect on the actual use of the product, and the thickness of the release film can be freely selected according to actual needs without special limitation, for example, it can be 25-100μm, and specifically it can be 25μm, 40μm, 60μm, 80μm, 100μm or any value between any two end values.

[0058] In actual operation, the drying temperature in the drying treatment can be 110-130℃, and the drying time can be 5-20min.

[0059] The third aspect of the present application provides the application of the optical adhesive of the first aspect of the present application in a vehicle-mounted display device.

[0060] Example 1

[0061] The present embodiment provides a preparation method of an optical adhesive, comprising the following steps:

[0062] (1) Preparation of an acrylate compound as shown in Formula I:

[0063] Into a four-necked flask with a stirrer, a thermometer, a nitrogen inlet tube, a reflux condenser and a dropping funnel, 1mol of 2-hydroxyethyl acrylate, 1mol of 3-fluoro-4-carboxyphenylboronic acid and 0.1mol of DMAP were added, stirred uniformly, then 1.1mol of DCC was added, and reacted at 25℃ for 8 hours to obtain an acrylate compound as shown in Formula I.

[0064]

[0065] (2) Preparation of an acrylic resin:

[0066] Into a four-necked flask with stirrer, thermometer, nitrogen inlet tube, reflux condenser, dropping funnel, 13 g of methyl acrylate, 74 g of butyl acrylate, 4 g of 2-hydroxyethyl acrylate, 2 g of acrylamide, 7 g of the compound of Formula I, 0.2 g of dibenzoyl peroxide and 100 g of toluene were added. The mixture was reacted at 90°C for 8 h, then cooled to 40°C and discharged to obtain an acrylic resin. The weight average molecular weight Mw of the acrylic resin was 115 x 10 4 , and the Mw / Mn molecular weight distribution width was 4.

[0067] (3) Preparation of optical adhesive

[0068] The acrylic resin prepared in step (2) of 100 g, isocyanate crosslinking agent (Desmodur N3390) of 0.3 g and ethyl acetate of 20 g were weighed according to the proportion, mixed uniformly to obtain a mixture; the mixture was coated on the surface of a 75 μm thick release film substrate (such as PET), dried at 120°C for 10 min to obtain an adhesive layer with a thickness of 250 μm, and a 50 μm thick PET release film was coated on the other side of the adhesive layer to obtain an optical adhesive.

[0069] Example 2

[0070] This example refers to the preparation method of the optical adhesive of Example 1, the only difference being that the amount of each monomer in step (2) of preparing the acrylic resin is different.

[0071] Step (2) of this example includes: into a four-necked flask with stirrer, thermometer, nitrogen inlet tube, reflux condenser, dropping funnel, 13 g of methyl acrylate, 71 g of butyl acrylate, 4 g of 2-hydroxyethyl acrylate, 2 g of acrylamide, 10 g of the compound of Formula I, 0.2 g of dibenzoyl peroxide and 100 g of toluene were added. The mixture was reacted at 90°C for 8 h, then cooled to 40°C and discharged to obtain an acrylic resin. The weight average molecular weight Mw of the acrylic resin was 105 x 10 4 , and the Mw / Mn molecular weight distribution width was 3.6.

[0072] Example 3

[0073] This example refers to the preparation method of the optical adhesive of Example 1, the only difference being that the amount of each monomer in step (2) of preparing the acrylic resin is different.

[0074] The step (2) of the present example comprises: adding methyl acrylate 13 g, butyl acrylate 76 g, 2-hydroxyethyl acrylate 4 g, acrylamide 2 g, compound of formula I 5 g, dibenzoyl peroxide 0.2 g and toluene 100 g into a four-necked flask with stirrer, thermometer, nitrogen inlet tube, reflux condenser and dropping funnel, reacting at 90°C for 8 h, then discharging at 40°C to obtain an acrylic resin. The weight average molecular weight Mw of the acrylic resin is 99 x 10 4 , and the Mw / Mn molecular weight distribution width is 3.7.

[0075] Example 4

[0076] The present example refers to the preparation method of the optical adhesive of Example 1, and the difference is only that the amount of each monomer is different in the step (2) of preparing the acrylic resin.

[0077] The step (2) of the present example comprises: adding methyl acrylate 15 g, butyl acrylate 74 g, 2-hydroxyethyl acrylate 4 g, compound of formula I 7 g, dibenzoyl peroxide 0.2 g and toluene 100 g into a four-necked flask with stirrer, thermometer, nitrogen inlet tube, reflux condenser and dropping funnel, reacting at 90°C for 8 h, then discharging at 40°C to obtain an acrylic resin. The weight average molecular weight Mw of the acrylic resin is 120 x 10 4 , and the Mw / Mn molecular weight distribution width is 3.9.

[0078] Example 5

[0079] The present example refers to the preparation method of the optical adhesive of Example 1, and the difference is only that the amount of each monomer is different in the step (2) of preparing the acrylic resin.

[0080] The step (2) of the present example comprises: adding methyl acrylate 11 g, butyl acrylate 74 g, 2-hydroxyethyl acrylate 4 g, acrylamide 4 g, compound of formula I 7 g, dibenzoyl peroxide 0.2 g and toluene 100 g into a four-necked flask with stirrer, thermometer, nitrogen inlet tube, reflux condenser and dropping funnel, reacting at 90°C for 8 h, then discharging at 40°C to obtain an acrylic resin. The weight average molecular weight Mw of the acrylic resin is 125 x 10 4 , and the Mw / Mn molecular weight distribution width is 3.6.

[0081] Comparative Example 1

[0082] Comparative Example 1 refers to the preparation method of the optical adhesive of Example 1, and the difference is that the amount of each monomer is different in the step (2) of preparing the acrylic resin.

[0083] Step (2) of Comparative Example 1 includes: adding methyl acrylate 14 g, butyl acrylate 80 g, 2-hydroxyethyl acrylate 4 g, acrylamide 2 g, dibenzoyl peroxide 0.2 g, and toluene 100 g into a four-necked flask with a stirrer, a thermometer, a nitrogen inlet tube, a reflux condenser, and a dropping funnel, reacting at 90°C for 8 h, then discharging at 40°C to obtain an acrylic resin. The weight average molecular weight Mw of the acrylic resin is 120 x 10 4 , and the Mw / Mn molecular weight distribution width is 3.5.

[0084] Comparative Example 2

[0085] Comparative Example 2 refers to the preparation method of the optical adhesive of Reference Example 1, except that the amount of each monomer is different in step (2) of preparing the acrylic resin.

[0086] Step (2) of Comparative Example 2 includes: adding methyl acrylate 13 g, butyl acrylate 70 g, 2-hydroxyethyl acrylate 4 g, acrylamide 2 g, a compound represented by Formula I 11 g, dibenzoyl peroxide 0.2 g, and toluene 100 g into a four-necked flask with a stirrer, a thermometer, a nitrogen inlet tube, a reflux condenser, and a dropping funnel, reacting at 90°C for 8 h, then discharging at 40°C to obtain an acrylic resin. The weight average molecular weight Mw of the acrylic resin is 95 x 10 4 , and the Mw / Mn molecular weight distribution width is 4.6.

[0087] Comparative Example 3

[0088] Comparative Example 3 refers to the preparation method of the optical adhesive of Reference Example 1, except that the compound represented by Formula I is replaced by an equal amount of a compound represented by Formula II in step (2) of preparing the acrylic resin.

[0089] The preparation of the compound represented by Formula II includes: adding 1 mol of 2-hydroxyethyl acrylate, 1 mol of 4-carboxyphenylboronic acid, and 0.1 mol of DMAP into a four-necked flask with a stirrer, a thermometer, a nitrogen inlet tube, a reflux condenser, and a dropping funnel, stirring uniformly, then adding 1.1 mol of DCC, and reacting at 25°C for 8 h to obtain an acrylate compound represented by Formula II.

[0090]

[0091] Experimental Example

[0092] In order to compare and illustrate the properties of the optical adhesives prepared by different examples and comparative examples, the optical adhesives prepared by the examples and comparative examples are tested as follows, and the test results are shown in Table 1.

[0093] 25℃ peel strength: tested according to GB / T 2792-2014; the test substrate is 304 mirror stainless steel plate;

[0094] Rolling ball initial adhesion: tested according to GB / T 4852-2002;

[0095] 80℃ holding adhesion: tested according to GB / T 4851-2014; the test substrate is 304 mirror stainless steel plate;

[0096] Temperature resistance test: remove the release film on one side of the optical adhesive to be tested, use a press roller to adhere the optical adhesive to be tested on the side of the polarizing sheet to the surface of the polarizing sheet, then remove the release film on the other side, use a press roller to adhere the optical adhesive on the side to the glass cover plate; then place the assembly in a high-pressure defoaming machine for 50 min, then place it at 95℃ for 1000 h, visually observe the appearance, whether there are defects such as back foaming and warping, if not, it is passed;

[0097] Weather resistance test: remove the release film on one side of the optical adhesive to be tested, use a press roller to adhere the optical adhesive to be tested on the side of the polarizing sheet to the surface of the polarizing sheet, then remove the release film on the other side, use a press roller to adhere the optical adhesive on the side to the glass cover plate; then place the assembly in a high-pressure defoaming machine for 50 min, then place it at a temperature of 85℃ and a relative humidity of 85% in a constant temperature and humidity environment for 1000 h, visually observe the appearance, whether there are defects such as back foaming and warping, if not, it is passed.

[0098] Table 1: Test results of different optical adhesives

[0099]

[0100] From the above test results, it can be seen that the optical adhesive of the present application not only has good temperature resistance and weather resistance, but also has good peel strength, initial adhesion and cohesion, which can meet the requirements of optical adhesives for vehicle display.

[0101] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An optical adhesive, characterized in that, It includes acrylic resin and a crosslinking agent; the amount of the crosslinking agent is 0.1 wt% to 0.5 wt% of the acrylic resin; The acrylic resin is mainly obtained by copolymerization of acrylate monomers; the acrylate monomers include the following components by mass percentage: 10%–20% hard monomers, 70%–80% soft monomers, 3%–5% functional monomers, 1%–2% polar monomers, and 5%–10% acrylate compounds as shown in Formula I; ； R1 is selected from alkylene groups having 1 to 3 carbon atoms.

2. The optical adhesive according to claim 1, characterized in that, The hard monomers include methyl acrylate and / or methyl methacrylate.

3. The optical adhesive according to claim 1, characterized in that, The soft monomers include butyl acrylate and / or isooctyl acrylate.

4. The optical adhesive according to claim 1, characterized in that, The functional monomer is a hydroxyl-containing acrylate monomer.

5. The optical adhesive according to claim 4, characterized in that, The functional monomer includes at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, and hydroxypropyl methacrylate.

6. The optical adhesive according to claim 1, characterized in that, The polar monomer includes acrylamide.

7. The optical adhesive according to claim 1, characterized in that, The acrylic resin also includes an initiator and an organic solvent.

8. The optical adhesive according to claim 7, characterized in that, The amount of the initiator is 0.1 wt% to 0.3 wt% of the total amount of the acrylate monomers.

9. The optical adhesive according to claim 7, characterized in that, The amount of the organic solvent used is 80wt% to 120wt% of the total amount of the acrylate monomers.

10. The optical adhesive according to claim 1, characterized in that, The crosslinking agent is an isocyanate crosslinking agent.

11. A method for preparing the optical adhesive according to any one of claims 1 to 10, characterized in that, Includes the following steps: (a) Mix the components in proportion to obtain a mixture; (b) The mixture is coated onto the surface of a release film, dried, and then covered with a release film to obtain the optical adhesive.

12. The application of the optical adhesive according to any one of claims 1 to 10 or the optical adhesive prepared by the preparation method according to claim 11 in an automotive display device.

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