Optical adhesive and laminate for flexible panel

Abstract

This invention provides an optical adhesive and a laminate for flexible panels. The optical adhesive comprises: (A) a resin prepolymer having long straight side chains; (B) a crosslinking agent; and (C) a catalyst. Component (A) is obtained by reacting the following components: 10-40 parts by weight of a soft monomer; 2-15 parts by weight of a hard monomer; 1 part by weight of a hydroxyl (-OH) monomer; and 0.001-0.03 parts by weight of a thermal initiator, wherein the soft monomer comprises a long straight-chain soft acrylate monomer, and the hard monomer comprises an unsaturated ethylene double-bond monomer. Component (B) is 0.02-1 parts by weight relative to 100 parts by weight of component (A); and component (C) is 0.005-0.01 parts by weight.

Description

Technical Field

[0001] This invention relates to an optical adhesive and a laminate for flexible panels. Background Technology

[0002] Traditionally, glass has been used as a protective layer for various display panels. However, glass has disadvantages such as being heavy and easily broken, and it also poses environmental problems due to its high carbon emissions.

[0003] To address the aforementioned issues, and with the trend towards thinner and lighter displays and electronic devices, flexible materials such as acrylic sheets and polycarbonate sheets are increasingly being used to replace glass sheets as protective layers.

[0004] However, panels using flexible boards as protective layers are prone to delamination or warping (unable to return to flatness) during rolled storage and transportation or when subjected to environmental thermal shock. This may be due to creep between the molecules of the adhesive used to bond the panels and the protective layer, or a mismatch between the viscoelasticity and Poisson's ratio of the adhesive and the protective layer.

[0005] Due to the aforementioned possible reasons, thermal stress may easily be generated between the layers of the panel module during flexing or high temperature and humidity testing, which may cause interlayer delamination and degrade the quality of the panel module. Summary of the Invention

[0006] The present invention provides an optical adhesive and a laminate for flexible panels.

[0007] In some embodiments, an optical adhesive is provided, comprising: (A) a resin prepolymer having long straight side chains; (B) a crosslinking agent; and (C) a catalyst. The (A) prepolymer is obtained by reacting a mixture comprising: 10-40 parts by weight of a soft monomer; 2-15 parts by weight of a hard monomer; 1 part by weight of a hydroxyl (-OH)-containing monomer; and 0.001-0.03 parts by weight of a thermal initiator. The soft monomer is a long straight-chain soft acrylate monomer as shown in formula (I), and the hard monomer comprises an unsaturated ethylene double-bonded monomer, wherein n is an integer from 7 to 15. The (B) component is 0.02-1 parts by weight relative to 100 parts by weight of the (A) component; and the (C) component is 0.005-0.01 parts by weight.

[0008]

[0009] In some embodiments, a laminate for a flexible panel is also provided, comprising: the optical adhesive described above; and at least one substrate. The optical adhesive is located on the surface of the substrate. Detailed Implementation

[0010] To enable those skilled in the art to better understand and implement the objectives, technical features, and advantages of the present invention, the following description clarifies the technical features and implementation methods of the present invention and provides further explanation with preferred embodiments. However, the following description of embodiments is not intended to limit the present invention.

[0011] Definitions and Explanations of Terms

[0012] In this specification, Tg represents the glass transition temperature.

[0013] <Optical Adhesive>

[0014] The present invention provides an optical adhesive comprising: (A) a resin prepolymer having long straight side chains; (B) a crosslinking agent; and (C) a catalyst.

[0015] In the following cases, the optical adhesive having the above-described structure may be simply referred to as "the optical adhesive of the present invention" or simply as "optical adhesive". Furthermore, the resin prepolymer with long straight side chains of component (A) may be simply referred to as "component (A) of the present invention" or simply as "component (A)". Similarly, the crosslinking agent of component (B) may be simply referred to as "component (B) of the present invention" or simply as "component (B)"; and the catalyst of component (C) may be simply referred to as "component (C) of the present invention" or simply as "component (C)".

[0016] The optical adhesive of the present invention, by means of component (A) having specific components and component (B) controlling the degree of crosslinking of the optical adhesive, enables the optical adhesive to have good creep resistance and achieve good stress absorption effect, thereby making it suitable as an adhesive layer for flexible panels or flexible composite boards.

[0017] <(A)Component>

[0018] The present invention (A) comprises a resin prepolymer with long straight side chains, obtained by reacting the following components: (a) 10-40 parts by weight of a soft monomer, wherein the soft monomer may be a long straight-chain soft acrylate monomer, or may be a mixture of a long straight-chain soft acrylate monomer (first soft monomer) and a soft monomer with Tg≦0℃ (second soft monomer); (b) 2-15 parts by weight of a hard monomer, wherein the hard monomer may be an unsaturated ethylene double bond monomer or may be a mixture of an unsaturated ethylene double bond monomer (first hard monomer) and the hard acrylate monomer (second hard monomer); (c) 1 part by weight of a hydroxyl (-OH)-containing monomer; and (d) 0.001-0.03 parts by weight of a thermal initiator.

[0019] [Soft monomer]

[0020] In some embodiments, relative to 1 part by weight of the hydroxyl (-OH) monomer in component (c) of component (A), the soft monomer of the present invention (a) may be 10-40 parts by weight, for example 10-30 parts by weight or 10-20 parts by weight.

[0021] In some embodiments, the soft monomer (a) used in component (A) of the present invention may be a long-chain soft acrylate monomer, specifically, as shown in formula (I):

[0022]

[0023] Where n can be an integer from 7 to 15, but is not subject to this restriction.

[0024] In some embodiments, there are no particular limitations on the specific examples of long-chain soft acrylate monomers, for example, the following groups can be selected: n-octyl(meth)acrylate, n-decyl(meth)acrylate, lauryl(meth)acrylate (LA), myristyl(meth)acrylate, and palmityl(meth)acrylate.

[0025] Based on the viewpoint that it can make optical adhesives have better creep resistance and better stress absorption effect, the long straight-chain soft acrylate monomer can be lauryl acrylate (LA), whose structure is shown in formula (I-1).

[0026]

[0027]

[0028] In some embodiments, in addition to the aforementioned long-chain soft acrylate monomer (first soft monomer), the (a) soft monomer of component (A) of the present invention may optionally contain a soft monomer (second soft monomer) with Tg≦0°C. The proportion of the second soft monomer with Tg≦0°C may be up to 60 wt% of the total soft monomer (i.e., the sum of the first soft monomer and the second soft monomer). That is, the second soft monomer may account for 0 wt% to 60 wt% of the total (a) soft monomer, for example, 0 wt%-50 wt%, 0 wt%-45 wt%, 0 wt%-40 wt%, 1 wt%-60 wt%, 1 wt%-50 wt%, or 1 wt%-40 wt%.

[0029] In some embodiments, the soft monomer of the present invention with Tg ≦ 0°C may specifically be selected from, for example, the group consisting of: butyl acrylate, sec-butyl(meth)acrylate, ethyl(meth)acrylate, 2-ethylhexyl(meth)acrylate (2-EHA), ethoxyethyl(meth)acrylate, and isononyl(meth)acrylate.

[0030] Based on the view that it can make optical adhesives have better creep resistance and better stress absorption effect, the soft monomer with Tg≦0℃ can be isooctyl (2-ethylhexyl(meth)acrylate, 2-EHA), whose structure is shown in formula (II).

[0031]

[0032] [Hard monomer]

[0033] In some embodiments, relative to 1 part by weight of the hydroxyl (-OH) monomer in component (c) of the present invention, the hard monomer in component (b) of the present invention may be 2-15 parts by weight, for example 2-10 parts by weight or 3-10 parts by weight.

[0034] In some embodiments, the (b) hard monomer used in this invention may be a hard monomer with Tg ≥ 85°C, but is not limited thereto.

[0035] In some embodiments, the hard monomer of component (b) of the present invention (A) may be an unsaturated ethylene double bond monomer.

[0036] In some embodiments, there are no particular limitations on specific examples of unsaturated ethylene double bond monomers that are the hard monomers of (b) of the present invention, such as acrylonitrile, acrylamide, acryloyl morpholine, and N-vinyl-2-pyrrolidone (NVP).

[0037] Based on the viewpoint that optical adhesives can have better creep resistance and better stress absorption performance, the unsaturated ethylene double bond monomer of the present invention can be N-vinyl-2-pyrrolidone (NVP), the structure of which is shown in formula (III).

[0038]

[0039] In some embodiments, the hard monomer of component (b) of the present invention, in addition to the aforementioned unsaturated ethylene double bond monomer (first hard monomer), may optionally include a hard acrylic monomer (second hard monomer). In some embodiments, the hard acrylic monomer (second hard monomer) may account for up to 40 wt% of the total (b) hard monomers (i.e., the sum of the first hard monomer and the second hard monomer), that is, the hard acrylic monomer (second hard monomer) accounts for 0 wt% to 40 wt% of the (b) hard monomers, for example, 0 wt%-30 wt%, 0 wt%-25 wt%, 1 wt%-40 wt%, 1 wt%-30 wt%, or 1 wt%-25 wt%.

[0040] In some embodiments, there are no particular limitations on the specific examples of the hard acrylic monomer (second hard monomer) of the present invention. For example, it may be selected from the group consisting of: tert-butyl(meth)acrylate, butyl methacrylate, cyclohexyl(meth)acrylate, isobornyl(meth)acrylate (IBOA), and methyl(meth)acrylate.

[0041] Based on the viewpoint that optical adhesives can have better creep resistance and better stress absorption performance, the hard acrylic monomer (second hard monomer) of the present invention can be isobornyl(meth)acrylate (IBOA), the structure of which is shown in formula (IV).

[0042]

[0043] [Hydroxy (-OH) monomers]

[0044] In some embodiments, component (A) of the present invention contains a hydroxyl (-OH) monomer, specifically, it may be selected from, for example, the group consisting of: hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, hydroxybutyl(meth)acrylate (4-HBA), hydroxypentyl(meth)acrylate, and hydroxyhexyl(meth)acrylate.

[0045] Based on the view that it can make the optical adhesive have better creep resistance and better stress absorption effect, (c) the hydroxyl (-OH) monomer can be hydroxybutyl(meth)acrylate (4-HBA), whose structure is shown in formula (V).

[0046]

[0047] [Thermal initiator]

[0048] The content of the thermal initiator (d) used in component (A) of the present invention is not particularly limited and can be adjusted as needed depending on the type and amount of monomer selected and the expected degree of polymerization. In some embodiments, the thermal initiator (d) may be 0.001-0.03 parts by weight relative to 1 part by weight of the hydroxyl (-OH) monomer (c) in component (A) of the present invention.

[0049] In some embodiments, specific examples of thermal initiators may be selected from the group consisting of: azobisisobutyronitrile (AIBN), benzoyl peroxide, cumyl hydroperoxide, dicumyl peroxide, tert-butyl hydroperoxide, tert-butylmonoperoxymaleate, diacetyl peroxide, and dilauroyl peroxide, but are not limited thereto.

[0050] Based on the view that it can make optical adhesives have better creep resistance and better stress absorption effect, the thermal initiator can be azobisisobutyronitrile (AIBN), whose structure is shown in formula (VI).

[0051]

[0052] <(B) Ingredients>

[0053] Component (B) of the present invention is a crosslinking agent used to control the degree of crosslinking of the optical adhesive. Component (B) may be 0.02-1 parts by weight relative to 100 parts by weight of component (A) of the present invention.

[0054] Component (B) of the present invention may be selected as needed, depending on the type and amount of other monomers used and the expected degree of crosslinking.

[0055] In some embodiments, specific examples of component (B) of the present invention may be organic peroxides or isocyanates, but are not limited thereto.

[0056] In some embodiments, examples of organic peroxides include: tetrahydrofuran peroxide, ethylene glycol dimethyl ether peroxide, benzoyl peroxide, methyl ethyl ketone peroxide, triacetone triperoxide, peroxyacetyl nitrate, dicyclooxyethylene, peracetic acid, ether peroxide, and cumene hydroperoxide.

[0057] In some embodiments, the isocyanate may be a monoisocyanate or a polyisocyanate, among which examples of polyisocyanates include: toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), and dicyclohexylmethane diisocyanate (HDI). 12 MDI and lysine diisocyanate (LDI).

[0058] In some embodiments, component (B) of the present invention may also be a commercially available product, for example, one manufactured by Covestro AG. N3200.

[0059] <(C) Ingredients>

[0060] The component (C) of the present invention is a catalyst, and the component (C) may be 0.005-0.01 parts by weight relative to 100 parts by weight of component (A) of the present invention.

[0061] In some embodiments, for environmental protection reasons, component (C) of the present invention may be an organometallic catalyst; specifically, component (C) of the present invention may be a tin-free catalyst.

[0062] In some embodiments, component (C) of the present invention may also be a commercially available product, for example, one manufactured by Borchers (Milliken) Inc. Kat 0243, Kat 15, etc.

[0063] [Laminated material for flexible panels]

[0064] Some embodiments of the present invention may also provide a laminate for a flexible panel, comprising: an optical adhesive; and at least one substrate. The optical adhesive may be located on the surface of the substrate or sandwiched between two substrates to form a three-layer laminate structure.

[0065] In some embodiments, the substrate material may be selected from the group consisting of: polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET), polyvinyl chloride (PVC), thermoplastic polyurethane elastomer (TPU), and styrene-acrylonitrile copolymer (AS) and polyimide (PI).

[0066] Examples and Comparative Examples

[0067] The following examples illustrate the present invention in more detail, but the present invention is not limited to these examples.

[0068] [Synthesis example of resin prepolymer with long straight side chains]

[0069] The resin prepolymers (1) to (7) were prepared using a Soxhlet extractor. First, according to Table 1, 10% of the monomer combination and 25% of the solvent (ethyl acetate) were weighed and placed into a flask. Then, the remaining 90% of the monomer combination, azobisisobutyronitrile as a thermal initiator, and 75% of the solvent (ethyl acetate) were added dropwise over a feeding time of 8 hours. The mixture was stirred at a rate of 200 rpm at a reaction temperature of 80°C for 40 hours. Then, 2,6-dibutyl-p-cresol as a terminator was added and heating was stopped. After cooling, stirring was stopped and the mixture was collected to obtain the resin prepolymers (1) to (7) with long straight side chains.

[0070] Here, the long-chain, soft acrylate monomer (first soft monomer) is lauryl methacrylate (LA); the soft monomer with Tg≦0℃ (second soft monomer) is isooctyl methacrylate (2-EHA); the unsaturated ethylene double bond monomer (first hard monomer) is N-vinyl-2-pyrrolidone (NVP); the hard acrylate monomer (second hard monomer) is isobornyl methacrylate (IBOA); the hydroxyl (-OH)-containing monomer is hydroxybutyl methacrylate (4-HBA); and the thermal initiator is azobisisobutyronitrile (AIBN).

[0071] [Table 1]

[0072]

[0073] [Preparation of optical adhesive]

[0074] Examples 1 to 6 and Comparative Examples 1 to 5

[0075] First, according to Table 2-3, weigh out 300g (approximately 90-100g solid) of resin prepolymer (1) to (7) and 1.86g of 1% catalyst ( Kat 0243 (1.86g) was placed in a beaker, and then different weights of crosslinking agent (According to Table 2) were added. N3200) was added to a beaker and stirred until homogeneous to obtain the optical adhesives (A) to (K) of Examples 1 to 6 and Comparative Examples 1 to 5.

[0076] The optical adhesives (A) to (K) were applied to release film H350A (manufactured by Nan Ya Plastics Industrial Co., Ltd., model: NYN YA*Release Film H350A) using a wet coating method at a machine speed of 0.3-0.5 m / min and an air duct setting of 65℃ / 80℃ / 90℃-120℃. Afterwards, drying was performed using an oven. On the opposite side of the bonding surface between the optical adhesives of Examples 1 to 6 and Comparative Examples 1 to 5 and the release film H350A, release film L150A (manufactured by Nan Ya Plastics Industrial Co., Ltd., model: NYN YA*Release Film L150A) was bonded and wound-cured at 50℃ for 24 hours to obtain a three-layer structure of release film H350A-optical adhesive-release film L150A. Remove the release film sandwiched between the two sides of the optical adhesive to obtain the prepared film (100 μm thick) of optical adhesive (A) to (K). Various physical properties of the optical adhesive are measured by the method described below, and the results are summarized in Table 2-3.

[0077] [Poisson's ratio test]

[0078] Poisson's ratio (γ) is determined by bonding the aforementioned optical adhesives (A) to (K) into a tensile testing machine at room temperature, according to A. The literature "Application of the finite element method in the tensile-shear test of adhesive technology" (doi:10.1016 / S0143-7496(01)00012-4) describes the "method for conducting shear force tests and calculation of Poisson's ratio". The (E) Young's modulus and (G) shear modulus are obtained and calculated using the following formula:

[0079]

[0080] [Relaxation Time (Creep Resistance) Measurement]

[0081] At room temperature, the films formed by the aforementioned optical adhesives (A) to (K) are bonded to a tensile testing machine, stretched to 50% and fixed for 15 minutes. After relaxation, the recovery time required for the adhesive is measured, and the result is taken as the "relaxation time" in seconds.

[0082] [Peel-off adhesion test]

[0083] One side of the aforementioned optical adhesive film (100 μm thick) was bonded to a 1.0 mm support material, and the other side was bonded to a transparent PI film (manufactured by Lusheng Technology Co., Ltd., model: MCF025), resulting in a sample with a width of 24 ± 0.5 mm. The transparent PI film was stretched and peeled at a constant speed of 300 mm / min, with parameters set according to ASTM D3330, thereby measuring the peel adhesion of optical adhesives (A) to (K).

[0084] [Test of Thermal Warpage Deformation under High Temperature and High Humidity]

[0085] As mentioned above, after fabricating the three-layer structure of release film H350A - optical adhesive - release film L150A of Examples 1 to 6 and Comparative Examples 1 to 5, release film L150A was removed and transparent PI was laminated on the surface. Then, release film H350A was removed and polymethyl methacrylate (PMMA) support material was laminated on the surface to create a laminate with a length of 76.4 mm. The laminate was placed on a metal substrate and subjected to a high temperature and high humidity environment of 85°C / 85% for 4 hours. The deformation of the laminate was then measured, and the result is the "thermal warpage deformation under high temperature and high humidity" of optical adhesives (A) to (K).

[0086] [Table 2]

[0087] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Resin prepolymer (3) (3) (4) (5) (6) (7) NVP as a percentage of total weight (wt.%) 17.0 17.0 16.7 16.2 15.5 20.6 IBOA percentage by weight (wt.%) 4.7 4.7 4.7 4.5 4.3 0 4-HBA percentage by weight (wt.%) 4.9 4.9 4.8 4.6 4.4 4.9 2-EHA percentage by weight (wt.%) 31.8 31.8 25.0 15.2 0.0 32.3 LA as a percentage of total weight (wt.%) 41.6 41.6 48.9 59.4 75.7 42.2 Catalyst (1%) weight (g) 1.86 1.86 1.86 1.86 1.86 1.86 Crosslinking agent (g) 0.15 0.23 0.23 0.23 0.23 0.23 Optical adhesive (A) (B) (C) (D) (E) (F) Poisson's ratio 0.43 0.43 0.47 0.48 0.49 0.42 Relaxation time (seconds) 32 40 38 30 25 59 180° peel adhesion (>10 N / in) 11.3 15.5 15.0 14.3 12.8 10.5 Peel-off test (failure interface) OCA-PI OCA-PI OCA-PI OCA-PI OCA-PI OCA-PI High temperature and high humidity warping deformation (<0.1 mm) 0 0 0 0 0 0

[0088] [Table 3]

[0089] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Resin prepolymer (1) (2) (3) (3) (3) NVP as a percentage of total weight (wt.%) 18.8 17.9 17.0 17.0 17.0 IBOA percentage by weight (wt.%) 5.3 5.0 4.7 4.7 4.7 4-HBA percentage by weight (wt.%) 5.4 5.1 4.9 4.9 4.9 2-EHA percentage by weight (wt.%) 70.5 50.2 31.8 31.％ 31.8 LA as a percentage of total weight (wt.%) 0.0 21.8 41.6 41.6 41.6 Catalyst (1%) weight (g) 1.86 1.86 1.86 1.86 1.86 Crosslinking agent (g) 0.23 0.23 0.37 0.07 0.5 Optical adhesive (G) (H) (I) (J) (K) Poisson's ratio 0.43 0.41 0.41 0.46 0.38 Relaxation time (seconds) 420 73 51 20 68 180° peel adhesion (>10 N / in) 17.4 17.0 13.5 8.3 9.7 Peel-off test (failure interface) OCA-PI OCA-PI OCA-PI OCA OCA-PI High temperature and high humidity warping deformation (<0.1 mm) 2.3 0.4 0.2 0 0.3

[0090] Based on the results in Tables 2-3, it can be seen that compared to the optical adhesives (A) to (F) of the present invention, optical adhesives (G) to (H) use fewer long-chain soft acrylate monomers, have longer relaxation times, and exhibit greater thermal warpage deformation under high temperature and humidity. Optical adhesive (I) uses more crosslinking agents, resulting in greater thermal warpage deformation under high temperature and humidity compared to optical adhesives (A) to (F) of the present invention, and also has a longer relaxation time. Furthermore, optical adhesives (J) to (K) use fewer crosslinking agents, resulting in poorer peel test results compared to optical adhesives (A) to (F) of the present invention, and optical adhesive (K) also has a longer relaxation time.

[0091] Furthermore, the peel test results show that after bonding optical adhesives (A) to (K) with polymethyl methacrylate (PMMA) and polyimide (PI) and then performing peel tests, optical adhesive (J) left residue on both sides of PI and PMMA (the cross-linking degree of the optical adhesive was too small, resulting in cohesion failure in the optical adhesive layer), while the other optical adhesives did not leave residue on the PI side (the failure interface was at the OCA-PI interface).

[0092] The comparison results show that the optical adhesives of some embodiments of the present invention have good creep resistance (low relaxation time) and stress absorption effect (low high temperature and high humidity warping deformation), and can be appropriately applied to flexible panels, etc.

[0093] Although the technical content of the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any modifications and refinements made by those skilled in the art without departing from the spirit of the present invention should be included within the scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. An optical adhesive, comprising: (A) Component, a resin prepolymer with long straight side chains; (B) Component, cross-linking agent; as well as (C) Components, catalysts, Component (A) is obtained by reacting the following components: (a) 10-40 parts by weight of soft monomers, including long-chain soft acrylate monomers as shown in formula (I), Where n is an integer from 7 to 15; (b) 2-15 parts by weight of hard monomer; (c) 1 part by weight of the hydroxyl-containing monomer; and (d) 0.001-0.03 parts by weight of thermal initiator, Wherein, relative to 100 parts by weight of component (A), component (B) is 0.02-1 parts by weight; and component (C) is 0.005-0.01 parts by weight.

2. The optical adhesive as described in claim 1, characterized in that, The soft monomer of component (A) accounts for 10-20 parts by weight relative to 1 part by weight of the hydroxyl-containing monomer.

3. The optical adhesive as described in claim 1, characterized in that, The hard monomer of component (A) accounts for 2-10 parts by weight relative to 1 part by weight of the hydroxyl-containing monomer.

4. The optical adhesive as described in claim 1, characterized in that, The soft monomer further comprises: a soft monomer with Tg≦0℃, wherein the soft monomer with Tg≦0℃ accounts for at most 60wt% of the soft monomer in (a).

5. The optical adhesive as described in claim 4, characterized in that, The soft monomer with Tg≦0℃ accounts for 0.1wt%-50wt% of the soft monomer.

6. The optical adhesive as described in claim 1, characterized in that, The hard monomer further comprises: a hard acrylic monomer, wherein the hard acrylic monomer accounts for at most 40 wt% of the hard monomer.

7. The optical adhesive as described in claim 6, characterized in that, The hard acrylic monomer accounts for 1 wt% to 40 wt% of the hard monomer.

8. The optical adhesive as described in claim 1, characterized in that, The unsaturated ethylene double bond monomer is selected from the group consisting of acrylonitrile, acrylamide, acrylamide morpholine, and N-vinyl-2-pyrrolidone.

9. The optical adhesive as described in claim 6, characterized in that, The hard acrylic monomer is selected from the group consisting of: tert-butyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, and methyl methacrylate.

10. The optical adhesive as described in claim 1, characterized in that, The long-chain soft acrylate monomers as shown in formula (I) are selected from the group consisting of: n-octyl methacrylate, n-decyl methacrylate, lauryl methacrylate, myristyl methacrylate, and palmitate methacrylate.

11. The optical adhesive as described in claim 1, characterized in that, The hydroxyl-containing monomer is selected from the group consisting of: hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, hydroxypentyl methacrylate, and hydroxyhexyl methacrylate.

12. The optical adhesive as claimed in claim 4, wherein, The soft monomer with Tg≦0℃ is selected from the group consisting of: n-butyl methacrylate, sec-butyl methacrylate, ethyl methacrylate, isooctyl methacrylate, ethoxyethyl methacrylate, and isononyl methacrylate.

13. A laminate for a flexible panel, comprising: Optical adhesive as described in any one of claims 1 to 12; as well as At least one substrate, The optical adhesive is located on the surface of the substrate. The substrate is made of a material selected from the group consisting of: polymethyl methacrylate, polycarbonate, polyethylene terephthalate, polyvinyl chloride, thermoplastic polyurethane elastomer, styrene-acrylonitrile copolymer, and polyimide.

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