OCA optical adhesive and preparation method therefor, and touch screen

Abstract

The present application relates to the technical field of optical adhesives and in particular to an OCA optical adhesive and a preparation method therefor, and a touch screen. The OCA optical adhesive comprises the following components in parts by weight: 85-95 parts of a modified silicone prepolymer, 5-15 parts of a crosslinking agent, 0.01-0.1 part of a first photoinitiator, and 0.1-2 parts of a functional additive. The modified silicone prepolymer is mainly prepared from the following components in parts by weight: 30-60 parts of vinyl-terminated siloxane, 40-70 parts of a monomer, 0.01-1 part of a second photoinitiator, and 0.002-0.2 parts of a chain transfer agent. The functional additive comprises: (a) tetrabutylammonium bromide; and (b) an optional additional additive selected from at least one of aluminum acetylacetonate and triphenylphosphine. In the present application, a host resin is modified with silicone, and at the same time, a specific functional additive is introduced into the system, so that when bonding a low-surface-energy substrate, the bonding performance can be significantly improved, and the fitting performance can be ensured.

Description

OCA optical adhesive, preparation method thereof and touch screen TECHNICAL FIELD

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

[0002] With the development of domestic electronic industry, electronic touch display has been widely popularized. As the bonding material of touch display screen, OCA optical adhesive can be used as an important material for filling and bonding.

[0003] Acrylic system is a main system in optical adhesive. The adhesive is prepared by mixing resin, functional monomer, diluent monomer, photoinitiator and additive, and then film is formed and cured. The bonding force of acrylic system adhesive to PET and glass substrates is very large, but the bonding force to substrates with low surface energy is very low, which is difficult to effectively bond. In the prior art, in order to improve the bonding performance of OCA optical adhesive to low surface energy substrates, various substances are introduced, but the improvement of bonding performance is limited.

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

[0005] The following is a summary of the subject matter described in detail in this document. This summary is not intended to limit the scope of protection of the claims.

[0006] One object of the present application is to provide an OCA optical adhesive, which has excellent bonding performance to low surface energy substrates, and also has good high temperature resistance and bonding stability.

[0007] Another object of the present application is to provide a preparation method of OCA optical adhesive.

[0008] Still another object of the present application is to provide a touch screen.

[0009] In order to achieve the above object, the present application provides an OCA optical adhesive, which comprises the following components in parts by weight: modified organosilicon prepolymer 85-95 parts, crosslinking agent 5-15 parts, first photoinitiator 0.01-0.1 parts and functional additive 0.1-2 parts.

[0010] The modified organosilicon prepolymer is mainly prepared from the following components in parts by weight: end-vinyl siloxane 30-60 parts, monomer 40-70 parts, second photoinitiator 0.01-1 parts and chain transfer agent 0.002-0.2 parts.

[0011] The functional additive comprises:

[0012] (a) tetrabutylammonium bromide;

[0013] (b) optionally, other auxiliary agents selected from at least one of aluminum acetylacetonate and triphenylphosphine.

[0014] In the detailed description of the application, the mass ratio of the tetrabutylammonium bromide to the other auxiliary agents is 3:(1-9).

[0015] In the detailed description of the application, the mass ratio of the end-vinyl siloxane in the modified silicone prepolymer to the functional auxiliary agent is (50-200):1.

[0016] In the detailed description of the application, the crosslinking agent includes at least one of 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, ethylene glycol dimethacrylate, cyclohexane dimethanol diacrylate, pentaerythritol triacrylate, tris(2-hydroxyethyl) isocyanurate triacrylate, trimethylolpropane triacrylate, ditrimethylolpropane acrylate, and dipentaerythritol hexaacrylate.

[0017] In the detailed description of the application, the first photoinitiator and the second photoinitiator each independently include at least one of photoinitiator TPO, photoinitiator 184, and photoinitiator 1173.

[0018] In the detailed description of the application, the viscosity of the modified silicone prepolymer is 2500-4000 cps.

[0019] In the detailed description of the application, the end-vinyl siloxane is methyl vinyl polysiloxane. Further, the viscosity of the end-vinyl siloxane is 200-1000 cps.

[0020] In the detailed description of the application, the monomer includes at least one of isooctyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, vinyl acetate, acrylamide, methyl methacrylate, methyl acrylate, acrylic acid, hydroxyethyl acrylate, hydroxypropyl acrylate, maleic anhydride, isobutyl acrylate, 2-phenoxyethyl acrylate, and 4-acryloyl morpholine.

[0021] In the detailed description of the application, the chain transfer agent includes at least one of ethyl mercaptan, butyl mercaptan, dodecyl mercaptan, and phenyl mercaptan.

[0022] Another aspect of the application provides a preparation method of the OCA optical adhesive as described above, including the following steps: mixing the components in proportion, and then ultraviolet curing and forming.

[0023] In the detailed description of the application, in the ultraviolet curing, the ultraviolet wavelength is 200-400 nm, and the ultraviolet energy is 600-1000 mj / cm 2 .

[0024] Another aspect of the present application provides a touch screen comprising the OCA optical glue described above.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] (1) The present application uses organic silicon to modify the main resin, reduces the surface energy of the whole system, and promotes the wetting of the system on the surface of the low surface energy substrate; at the same time, specific functional additives are introduced into the system, the functional additives can be arranged on the surface of the OCA optical glue, and the bonding performance is significantly improved when bonding the low surface energy substrate, and the bonding performance is ensured.

[0027] (2) The preparation process of the OCA optical glue of the present application is simple, safe and environmentally friendly, and has excellent economic benefit, production benefit and environmental benefit.

[0028] Other aspects can be appreciated upon reading and understanding the detailed description. DETAILED DESCRIPTION

[0029] The technical solutions of the present application will be described in detail below in conjunction with specific embodiments, 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 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, which 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, which are conventional products that can be purchased on the market.

[0030] One aspect of the present application provides an OCA optical glue, comprising the following components by weight fraction: modified organic silicon prepolymer 85-95 parts, crosslinking agent 5-15 parts, first photoinitiator 0.01-0.1 parts and functional additive 0.1-2 parts;

[0031] The modified organic silicon prepolymer is mainly prepared from the following components by weight fraction: end-vinyl siloxane 30-60 parts, monomer 40-70 parts, second photoinitiator 0.01-1 parts and chain transfer agent 0.002-0.2 parts;

[0032] The functional additive includes:

[0033] (a) tetrabutylammonium bromide;

[0034] (b) optional other additives, the other additives are selected from at least one of aluminum acetylacetone and triphenylphosphine.

[0035] The OCA optical adhesive of the present application is prepared by matching various components. On the one hand, the main resin is modified by using organosilicon to reduce the surface energy of the whole system and promote the wetting of the system on the surface of the low surface energy substrate. At the same time, a certain amount of specific functional additives is introduced into the system. The functional additives can be arranged on the surface of the OCA optical adhesive. When bonding the low surface energy substrate, the bonding performance is significantly improved, and the lamination performance is ensured.

[0036] As in different embodiments, the amount of each component used by the OCA optical adhesive can be as follows, by weight fraction:

[0037] The amount of modified organosilicon prepolymer can be 85 parts, 88 parts, 90 parts, 92 parts, 95 parts, or a range consisting of any two of them;

[0038] The amount of crosslinking agent can be 5 parts, 8 parts, 10 parts, 12 parts, 15 parts, or a range consisting of any two of them;

[0039] The amount of the first photoinitiator can be 0.01 parts, 0.05 parts, 0.08 parts, 0.1 parts, or a range consisting of any two of them;

[0040] The amount of the functional additive can be 0.1 parts, 0.5 parts, 0.8 parts, 1 parts, 1.2 parts, 1.5 parts, 1.8 parts, 2 parts, or a range consisting of any two of them.

[0041] As in different embodiments, the amount of each component used by the modified organosilicon prepolymer can be as follows, by weight fraction:

[0042] The amount of end-vinyl siloxane can be 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, or a range consisting of any two of them;

[0043] The amount of monomer can be 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, or a range consisting of any two of them;

[0044] The amount of the second photoinitiator can be 0.01 parts, 0.05 parts, 0.08 parts, 0.1 parts, or a range consisting of any two of them;

[0045] The amount of chain transfer agent can be 0.002 parts, 0.01 parts, 0.1 parts, 0.2 parts, or a range consisting of any two of them.

[0046] In a specific embodiment of the present application, the mass ratio of tetrabutylammonium bromide to other additives is 3:(1-9).

[0047] The amount of tetrabutylammonium bromide and other functional additives can further ensure the bonding performance of the OCA optical adhesive to the low surface energy substrate while ensuring the stability of the bonding. In different embodiments, the mass ratio of tetrabutylammonium bromide to other functional additives can be 3:1, 3:2, 1:1, 3:4, 3:5, 1:2, 3:7, 3:8, 1:3, or a range composed of any two of them, and further can be selected as 3:(2-4).

[0048] In the specific embodiments of the present application, the mass ratio of the terminal vinyl siloxane in the modified silicone prepolymer to the functional additive is (50-200):1.

[0049] Further regulating the mass ratio of the terminal vinyl siloxane in the modified silicone prepolymer to the functional additive helps to improve the bonding performance of the OCA optical adhesive to the low surface energy substrate and ensure the stability of the bonding, avoiding bubbles. The amount of terminal vinyl siloxane in the modified silicone prepolymer refers to the amount of raw material terminal vinyl siloxane used to prepare the corresponding modified silicone prepolymer. When the mass ratio of the terminal vinyl siloxane in the modified silicone prepolymer to the functional additive is too large, i.e., the amount of terminal vinyl siloxane in the modified silicone prepolymer is too much, the polarity of the modified silicone prepolymer is significantly reduced, and the degree of directional arrangement of the polar groups and non-polar groups of the functional additive is low, resulting in insufficient improvement in the bonding performance to the low surface energy substrate; when the mass ratio of the terminal vinyl siloxane in the modified silicone prepolymer to the functional additive is too small, i.e., the amount of terminal vinyl siloxane in the modified silicone prepolymer is too little, the polarity of the modified silicone prepolymer is not significantly reduced, although the degree of directional arrangement of the polar groups and non-polar groups of the functional additive is good, the overall wettability of the resin matrix to the low surface energy substrate is insufficient, which also leads to insufficient improvement in the bonding performance to the low surface energy substrate and poor bonding performance. In different embodiments, the mass ratio of the terminal vinyl siloxane in the modified silicone prepolymer to the functional additive of the present application can be 50:1, 60:1, 80:1, 100:1, 120:1, 150:1, 180:1, 200:1, or a range composed of any two of them, for example, (80-180):1.

[0050] In the specific embodiments of the present application, the crosslinking agent includes at least one of 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, ethylene glycol dimethacrylate, cyclohexane dimethanol diacrylate, pentaerythritol triacrylate, tris(2-hydroxyethyl) isocyanurate triacrylate, trimethylolpropane triacrylate, bistrimethylolpropane acrylate, and dipentaerythritol hexaacrylate.

[0051] In the detailed description of the application, the first photoinitiator and the second photoinitiator each independently comprise at least one of photoinitiator TPO, photoinitiator 184 and photoinitiator 1173.

[0052] In the detailed description of the application, the viscosity of the modified silicone prepolymer is 2500-4000 cps. Further, the preparation of the modified silicone prepolymer comprises: after the components are uniformly mixed, reacting under ultraviolet light irradiation until the viscosity reaches 2500-4000 cps, stopping the reaction, and obtaining the modified silicone prepolymer.

[0053] As in different embodiments, the viscosity of the modified silicone prepolymer can be 2500 cps, 2800 cps, 3000 cps, 3200 cps, 3500 cps, 3800 cps, 4000 cps, or a range consisting of any two of them. The viscosity of the modified silicone prepolymer is within the above range, which on the one hand can ensure the uniformity of mixing with the remaining components and ensure that the system has a certain fluidity; on the other hand, the degree of reaction is controlled, so that the system is fully cured when preparing the OCA optical adhesive, and the strength of the OCA optical adhesive is ensured.

[0054] In actual operation, the preparation of the modified silicone prepolymer is carried out in a protective atmosphere. For example, the uniformly mixed materials can be treated with nitrogen, and the ultraviolet light irradiation reaction is carried out in a nitrogen protective atmosphere.

[0055] In the detailed description of the application, the end-vinyl siloxane is methyl vinyl polysiloxane. Further, the viscosity of the end-vinyl siloxane is 200-1000 cps.

[0056] As in different embodiments, the viscosity of the end-vinyl siloxane of the application can be 200 cps, 400 cps, 500 cps, 800 cps, 1000 cps, or a range consisting of any two of them. The application does not make redundant descriptions on the methyl vinyl polysiloxane used, and any methyl vinyl polysiloxane with a viscosity meeting the above requirements can be used.

[0057] In the detailed description of the application, the monomer comprises at least one of isooctyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, vinyl acetate, acrylamide, methyl methacrylate, methyl acrylate, acrylic acid, hydroxyethyl acrylate, hydroxypropyl acrylate, maleic anhydride, isobutyl acrylate, 2-phenoxyethyl acrylate and 4-acryloyl morpholine.

[0058] In the detailed description of the application, the chain transfer agent comprises at least one of ethyl mercaptan, butyl mercaptan, dodecyl mercaptan and phenyl mercaptan.

[0059] In the detailed description of the present application, the OCA optical adhesive of the present application is arranged between the coating glass and the PET substrate with a water drop angle > 105° in the form of adhesive film, peeled at a speed of 300 mm / min, the peeling force at 25°C is ≥ 10 N / 25 mm, further alternatively ≥ 11 N / 25 mm, and more alternatively ≥ 12 N / 25 mm; the peeling force at 85°C is ≥ 2.0 N / 25 mm, further alternatively ≥ 2.5 N / 25 mm, and more alternatively ≥ 2.9 N / 25 mm.

[0060] Another aspect of the present application provides a preparation method of any one of the above OCA optical adhesives, comprising the following steps: mixing the components in proportion, and then ultraviolet curing.

[0061] In actual operation, the preparation of the OCA optical adhesive can include: coating the mixed material into a film, and then performing ultraviolet curing. The OCA optical adhesive is in the form of adhesive film, and the thickness can be 25-400 μm, which can be adjusted according to actual needs.

[0062] In the detailed description of the present application, in the ultraviolet curing, the ultraviolet wavelength is 200-400 nm, and the ultraviolet energy is 600-1000 mj / cm 2 . For example, a high-pressure mercury lamp can be used, but it is not limited thereto, and any light capable of initiating polymerization can be used.

[0063] Another aspect of the present application provides a touch screen comprising any one of the above OCA optical adhesives.

[0064] Example 1

[0065] The present embodiment provides a preparation method of OCA optical adhesive, comprising the following steps:

[0066] (1) Take 45 parts of methylvinyl polysiloxane (viscosity 400 cps), 35 parts of isooctyl acrylate, 7 parts of acrylic acid, 13 parts of 4-hydroxybutyl acrylate, 0.02 parts of dodecyl mercaptan, and 0.1 parts of photoinitiator 184 by weight, mix uniformly, fill with nitrogen for 30 min, irradiate with a mercury lamp to start polymerization, and when the reaction viscosity reaches about 3000 cps, terminate the reaction to obtain a modified silicone prepolymer.

[0067] (2) Take 90 parts of the modified silicone prepolymer prepared in step (1), 10 parts of 1,6-hexanediol diacrylate, 0.2 parts of tetrabutylammonium bromide, 0.2 parts of triphenylphosphine, and 0.1 parts of photoinitiator TPO by weight, stir uniformly, then degas, pour onto a release film, coat into a film and attach a release film, and cure under a mercury lamp for 3 min to obtain an OCA optical adhesive film with a thickness of 175 μm.

[0068] Example 2

[0069] This example refers to the preparation method of OCA optical adhesive of Example 1, the only difference is that the preparation of modified silicone prepolymer in step (1) is different.

[0070] The step (1) of this example includes: taking methyl vinyl polysiloxane 60 parts (viscosity is 400 cps), isooctyl acrylate 25 parts, acrylic acid 5 parts, 4-hydroxybutyl acrylate 10 parts, dodecyl mercaptan 0.02 parts, and photoinitiator 184 0.1 parts by weight fraction, uniformly mixed, filled with nitrogen for 30 min, irradiated with mercury lamp to start polymerization, when the reaction viscosity reaches about 3000 cps, the reaction is terminated, and the modified silicone prepolymer is obtained.

[0071] Example 3

[0072] This example refers to the preparation method of OCA optical adhesive of Example 1, the only difference is that the preparation of modified silicone prepolymer in step (1) is different.

[0073] The step (1) of this example includes: taking methyl vinyl polysiloxane 60 parts (viscosity is 400 cps), isooctyl acrylate 25 parts, acrylic acid 5 parts, 4-hydroxybutyl acrylate 10 parts, dodecyl mercaptan 0.02 parts, and photoinitiator 184 0.1 parts by weight fraction, uniformly mixed, filled with nitrogen for 30 min, irradiated with mercury lamp to start polymerization, when the reaction viscosity reaches about 3000 cps, the reaction is terminated, and the modified silicone prepolymer is obtained.

[0074] Example 4

[0075] This example refers to the preparation method of OCA optical adhesive of Example 1, the only difference is that the amount of tetrabutylammonium bromide and triphenylphosphine in step (2) is different.

[0076] In this example, the amount of tetrabutylammonium bromide is 0.4 parts, and the amount of triphenylphosphine is 0.4 parts.

[0077] Example 5

[0078] This example refers to the preparation method of OCA optical adhesive of Example 1, the only difference is that the amount of tetrabutylammonium bromide and triphenylphosphine in step (2) is different.

[0079] In this example, the amount of tetrabutylammonium bromide is 0.1 parts, and the amount of triphenylphosphine is 0.1 parts.

[0080] Example 6

[0081] This example refers to the preparation method of OCA optical adhesive of Example 1, the only difference is that the amount of tetrabutylammonium bromide and triphenylphosphine in step (2) is different.

[0082] In this embodiment, the amount of tetrabutylammonium bromide is 0.05 parts, and the amount of triphenylphosphine is 0.05 parts.

[0083] Example 7

[0084] This embodiment refers to the preparation method of the OCA optical adhesive of Example 1, and the only difference is that the amounts of tetrabutylammonium bromide and triphenylphosphine in step (2) are different.

[0085] In this embodiment, the amount of tetrabutylammonium bromide is 1 part, and the amount of triphenylphosphine is 1 part.

[0086] Example 8

[0087] This embodiment refers to the preparation method of the OCA optical adhesive of Example 1, and the only difference is that the amounts of tetrabutylammonium bromide and triphenylphosphine in step (2) are different.

[0088] In this embodiment, the amount of tetrabutylammonium bromide is 0.3 parts, and the amount of triphenylphosphine is 0.1 parts.

[0089] Example 9

[0090] This embodiment refers to the preparation method of the OCA optical adhesive of Example 1, and the only difference is that the amounts of tetrabutylammonium bromide and triphenylphosphine in step (2) are different.

[0091] In this embodiment, the amount of tetrabutylammonium bromide is 0.1 parts, and the amount of triphenylphosphine is 0.3 parts.

[0092] Example 10

[0093] This embodiment refers to the preparation method of the OCA optical adhesive of Example 1, and the only difference is that step (2) uses equal amounts of aluminum acetylacetonate instead of triphenylphosphine.

[0094] Example 11

[0095] This embodiment refers to the preparation method of the OCA optical adhesive of Example 1, and the only difference is that step (2) does not include triphenylphosphine, and the amount of tetrabutylammonium bromide is 0.4 parts.

[0096] Comparative Example 1

[0097] Comparative Example 1 refers to the preparation method of the OCA optical adhesive of Example 1, and the only difference is that in step (2), equal amounts of acrylic prepolymer are used instead of modified silicone prepolymer.

[0098] The preparation method of the acrylic prepolymer in Comparative Example 1 comprises: taking 35 parts of isooctyl acrylate, 7 parts of acrylic acid, 13 parts of 4-hydroxybutyl acrylate, 0.01 parts of dodecyl mercaptan, and 0.05 parts of photoinitiator 184 by weight, uniformly mixing, filling with nitrogen for 30 minutes, and irradiating with a mercury lamp to start polymerization. When the reaction viscosity reaches about 3000 cps, the reaction is terminated to obtain an acrylic prepolymer.

[0099] Comparative Example 2

[0100] Comparative Example 2 refers to the preparation method of the OCA optical adhesive of Example 1, except that no tetrabutylammonium bromide is included in step (2), and the amount of triphenylphosphine is 0.4 parts.

[0101] Comparative Example 3

[0102] Comparative Example 3 refers to the preparation method of the OCA optical adhesive of Example 1, except that 0.4 parts of aluminum acetylacetonate is used to replace all of the tetrabutylammonium bromide and triphenylphosphine in step (2).

[0103] Comparative Example 4

[0104] Comparative Example 4 refers to the preparation method of the OCA optical adhesive of Example 1, except that the amounts of tetrabutylammonium bromide and triphenylphosphine are different in step (2).

[0105] In Comparative Example 4, the amount of tetrabutylammonium bromide is 1.2 parts, and the amount of triphenylphosphine is 1.2 parts.

[0106] Experimental Example

[0107] In order to compare and illustrate the performance differences of the OCA optical adhesives of different examples and comparative examples, the following tests were respectively performed, and the test results are shown in Table 1.

[0108] Peeling force test: the OCA optical adhesive samples of each example and comparative example were respectively cut into 25 mm wide, and the release film was removed and attached to special coated glass (Dongguan Jingtuo New Glass Technology Co., Ltd., model jtx-230213-1) with a daN value of less than 24 and a water drop angle of greater than 105°, and the other side was attached to a 25 μm thick, 300 mm long, and corona treated PET. The peeling speed was 300 mm / min, the test temperature of the oven was set, and the average value of 5 groups of data was obtained according to the national standard.

[0109] Ring measurement application test: the OCA optical adhesive of each example and comparative example was respectively attached to the cover plate and then attached to the LCM, degassed, and left to stand for 24 hours. Then, the product was placed in a high temperature environment of 85°C and an environment of 85°C+85%RH, and it was confirmed whether there was a bubble rebound.

[0110] Table 1 Performance test results of different OCA optical adhesives

[0111] From the test results, it can be seen that by modifying the acrylic prepolymer with a certain amount of functional additives, the surface wettability and bonding performance to low surface energy substrates can be significantly improved, while ensuring good fitting performance. If the acrylic prepolymer is not modified or the corresponding functional additives are not used, both the bonding performance and the fitting performance to low surface energy substrates cannot be improved.

[0112] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features can be replaced by equivalents; 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 OCA optical glue comprising, by weight parts, the following components: a modified silicone prepolymer 85-95 parts, a crosslinking agent 5-15 parts, a first photoinitiator 0.01-0.1 parts, and a functional additive 0.1-2 parts. The modified silicone prepolymer is prepared from, by weight parts, the following components: a terminal vinyl siloxane 30-60 parts, a monomer 40-70 parts, a second photoinitiator 0.01-1 parts, and a chain transfer agent 0.002-0.2 parts. The functional additive comprises: (a) tetrabutylammonium bromide; (b) optionally other additives selected from at least one of aluminum acetylacetonate and triphenylphosphine.

2. The OCA optical glue of claim 1, wherein, The mass ratio of the tetrabutylammonium bromide to the other additives is 3:(1-9).

3. The OCA optical glue of claim 1, wherein, The mass ratio of the terminal vinyl siloxane in the modified silicone prepolymer to the functional additive is (50-200):

1.

4. The OCA optical glue of claim 1, wherein, The crosslinking agent comprises at least one of 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, ethylene glycol dimethacrylate, cyclohexane dimethanol diacrylate, pentaerythritol triacrylate, tris(2-hydroxyethyl)isocyanurate triacrylate, trimethylolpropane triacrylate, ditrimethylolpropane acrylate, and dipentaerythritol hexaacrylate.

5. The OCA optical glue of claim 1, wherein, The first photoinitiator and the second photoinitiator each independently comprises at least one of photoinitiator TPO, photoinitiator 184, and photoinitiator 1173.

6. The OCA optical glue of claim 1, wherein, The viscosity of the modified silicone prepolymer is 2500-4000 cps.

7. The OCA optical glue of claim 1, wherein, The terminal vinyl siloxane is methyl vinyl polysiloxane.

8. The OCA optical glue of claim 1, wherein, The monomer comprises at least one of isooctyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, vinyl acetate, acrylamide, methyl methacrylate, methyl acrylate, acrylic acid, hydroxyethyl acrylate, hydroxypropyl acrylate, maleic anhydride, isobutyl acrylate, 2-phenoxyethyl acrylate, and 4-acryloyl morpholine. 9.A method for preparing the OCA optical glue of any one of claims 1-8, comprising the step of: ultraviolet curing after mixing the components in proportion. 10.A touch screen comprising the OCA optical glue of any one of claims 1-8 or prepared by the method of claim 9.

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