UV adhesive for GOB packaging of LED display screen as well as preparation method and application of UV adhesive

Abstract

The invention relates to the field of LED display screen GOB packaging, and mainly relates to a UV adhesive for LED display screen GOB packaging and a preparation method and application thereof. The UV adhesive for packaging the GOB of the LED display screen is prepared from the following raw materials in parts by mass: 55 to 65 parts of polyurethane acrylate prepolymer, 30 to 35 parts of acrylate active monomer, 2 to 5 parts of photoinitiator and 0.1 to 0.5 part of rheological additive. The UV adhesive for GOB packaging of the LED display screen, provided by the invention, serves as single-component glue, the curing time takes second as a unit, the adhesive force and the low-temperature resistance are both superior to those of epoxy AB glue, the production efficiency is greatly improved, the shore hardness after curing meets the use performance, and meanwhile, the UV adhesive has good adhesive force, weather resistance and flexibility and is not prone to falling off.

Description

Technical Field

[0001] The present application relates to the field of LED display screen GOB packaging, and mainly to a UV glue for LED display screen GOB packaging and a preparation method and application thereof. Background Art

[0002] According to data, the global LED display market size reached US$8.29 billion in 2022 and grew to US$8.96 billion in 2023. As a major producer and consumer of LED displays, China's market size is also expanding, with a high average annual compound growth rate. It is expected that the global LED display market size will reach 72.648 billion yuan in 2028.

[0003] The scale of the global LED display market continues to expand. As a major producer and consumer, China occupies a pivotal position in the market scale. According to statistics, the scale of China's LED display market has increased year by year, from 53.2 billion yuan in 2020 to 63.5 billion yuan in 2022, and reached 68.4 billion yuan in 2023. It is expected that in the next few years, with the continuous advancement of technology and the continuous growth of market demand, the scale of China's LED display market will continue to maintain a rapid growth trend. The LED display industry can be subdivided into multiple fields, mainly including monochrome LED display and full-color LED display. Monochrome LED display is mainly used in traffic lights, indicator lights and other fields. Full-color LED display is widely used in advertising, video playback, stage performances and other scenes because it can present rich color combinations. In addition, with the development of technology, new display technologies such as small-pitch LED display and Micro / MiniLED are also gradually maturing.

[0004] GOB stands for GLUE ON THE BOARD, which means that a special resin glue material is used to fill the gaps between LED lamp beads on the basis of traditional SMD labels, so that each independent LED lamp bead on the board is closely connected to form a whole. This packaging method greatly enhances the connection strength between the LED lamp bead and the PCB board, and reduces the risk of the lamp bead falling off. GOB packaging technology realizes comprehensive protection of LED display screens, including waterproof, moisture-proof, dust-proof, anti-collision, anti-static and other functions. It enables the LED display screen to operate stably in various harsh environments.

[0005] At present, the GOB packaging of LED display screens mostly adopts epoxy AB glue potting, that is, glue A and curing agent B are mixed in proportion during production and filled into the gaps between LED lamp beads. However, the use of epoxy AB glue for packaging often has the following problems: 1. Long curing time (generally >20h) and low efficiency; 2. Two components, need to be mixed and stirred before use, and the process is complicated; 3. Poor adhesion, easy to fall off at low temperature, etc. Therefore, the existing technology needs to be improved and developed. Summary of the invention

[0006] In view of the above-mentioned deficiencies in the prior art, the purpose of this application is to provide a UV glue for GOB packaging of LED display screens and its preparation method and application, aiming to solve the problems of the existing packaging through epoxy AB glue, which has a long existence time, complex process and poor adhesion.

[0007] The technical solution of this application is as follows: In a first aspect, the present application provides a UV glue for encapsulating GOB of an LED display screen, which includes the following raw materials in parts by mass: 55-65 parts of polyurethane acrylate prepolymer, 30-35 parts of acrylate active monomer, 2-5 parts of photoinitiator, and 0.1-0.5 parts of rheological additive.

[0008] The UV glue for GOB packaging of LED display screens provided in this application is a single-component glue with a curing time measured in seconds. Its adhesion and low-temperature resistance are better than those of epoxy AB glue, which greatly improves production efficiency. Moreover, after curing, the Shore hardness not only meets the performance requirements, but also has good adhesion, weather resistance and flexibility, and is not easy to fall off.

[0009] Furthermore, the polyurethane acrylate prepolymer is one or both of aliphatic polyester polyurethane acrylate and polybutadiene polyurethane acrylate.

[0010] Further, the polyurethane acrylate prepolymer is a combination of aliphatic polyester polyurethane acrylate and polybutadiene polyurethane acrylate, and the mass ratio of the aliphatic polyester polyurethane acrylate to the polybutadiene polyurethane acrylate is 25:40; The aliphatic polyester polyurethane acrylate is obtained by an addition reaction of polyester diol, hexamethylene diisocyanate and hydroxyethyl acrylate, wherein the molar ratio of the polyester diol, hexamethylene diisocyanate and hydroxyethyl acrylate is 1:2:2; The polybutadiene polyurethane acrylate is obtained by the addition reaction of terminal hydroxyl polybutadiene and isophordione diisocyanate.

[0011] Furthermore, the acrylic acid ester active monomer is one or more of 2-(p-isopropylphenyl-phenoxy)-ethyl acrylate, 2-methyl-2-acrylate (tetrahydro-2-furanyl) methyl ester, ethylene glycol dicyclopentenyl ether acrylate, and propoxylated nonylphenol acrylate.

[0012] Furthermore, the acrylate active monomer is a combination of 2-(p-isopropylphenyl-phenoxy)-ethyl acrylate, 2-methyl-2-acrylate (tetrahydro-2-furanyl) methyl ester, ethylene glycol dicyclopentenyl ether acrylate, and propoxylated nonylphenol acrylate, and the mass ratio of the 2-(p-isopropylphenyl-phenoxy)-ethyl acrylate, 2-methyl-2-acrylate (tetrahydro-2-furanyl) methyl ester, ethylene glycol dicyclopentenyl ether acrylate, and propoxylated nonylphenol acrylate is 10:12:5:5.

[0013] Furthermore, the photoinitiator is one or both of 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide and 1-hydroxycyclohexyl phenyl ketone.

[0014] Furthermore, the rheological additive is a leveling agent BYK-333.

[0015] In a second aspect, the present application further provides a method for preparing UV glue for GOB encapsulation of LED display screens as described in the first aspect, which comprises the following steps: Add acrylate active monomer, photoinitiator and rheological additive into a container, heat to 40-50°C, and stir at 1200-1500 r / min for 20-30 min to mix; Add polyurethane acrylate prepolymer, heat to 50-60° C., stir at 1200-1800 r / min for 30-50 min to disperse, and obtain the UV glue for GOB encapsulation of the LED display screen.

[0016] In a third aspect, the present application further provides an application of the UV glue for GOB encapsulation of an LED display screen as described in the first aspect, wherein the UV glue for GOB encapsulation of an LED display screen is applied to the encapsulation of an LED display screen, comprising the following steps: Prepare the UV glue for GOB packaging of the LED display screen, and then apply it on the surface of the LED display screen; Remove bubbles, and after the LED display screen GOB packaging is leveled with UV glue, coat the surface of the LED display screen and press it flat; Using an ultraviolet light surface light source to irradiate the LED display screen GOB packaging UV glue to completely cure; Cut off the overflow glue around to get the packaged LED display; The coating method includes one of roller coating, screen printing and spraying; The method of removing bubbles includes one of leaving the mixture to stand or evacuating the mixture.

[0017] Furthermore, the power of the ultraviolet surface light source is 60W, the wavelength is 395nm, and the irradiation time is 15 seconds.

[0018] Beneficial effects: The UV glue for GOB packaging of LED display screens provided in this application is a single-component glue, and its curing time is measured in seconds. Its adhesion and low-temperature resistance are better than those of epoxy AB glue, which greatly improves production efficiency. Moreover, after curing, the Shore hardness not only meets the performance requirements, but also has good adhesion, weather resistance and flexibility, and is not easy to fall off. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a packaging effect diagram of the UV glue used for GOB packaging of the LED display screen in Example 1 of the present application. DETAILED DESCRIPTION

[0020] The present application provides a UV glue for GOB packaging of LED display screens and its preparation method and application. In order to make the purpose, technical solution and effect of the present application clearer and more specific, the present application is further described in detail below. It should be understood that the specific embodiments described here are only used to explain the present application and are not used to limit the present application.

[0021] The existing epoxy AB glue has a high hardness after being fully cured, usually above 80D on the Shore A scale, but has poor flexibility, poor adhesion in low temperature environments, and is prone to falling off as a whole.

[0022] To address this problem, the present application provides a UV glue for encapsulating GOB of LED display screens, which includes the following raw materials in terms of mass fraction: 55-65 parts of polyurethane acrylate prepolymer, 30-35 parts of acrylate active monomer, 2-5 parts of photoinitiator, and 0.1-0.5 parts of rheological additive.

[0023] The UV glue for GOB packaging of LED display screens provided in this application is a single-component glue with a curing time measured in seconds. Its adhesion and low-temperature resistance are better than those of epoxy AB glue, which greatly improves production efficiency. Moreover, after curing, the Shore hardness not only meets the performance requirements, but also has good adhesion, weather resistance and flexibility, and is not easy to fall off.

[0024] Furthermore, the polyurethane acrylate prepolymer is one or both of aliphatic polyester polyurethane acrylate and polybutadiene polyurethane acrylate.

[0025] Furthermore, the aliphatic polyester polyurethane acrylate is obtained by an addition reaction of polyester diol, hexamethylene diisocyanate, and hydroxyethyl acrylate, and the molar ratio of polyester diol, hexamethylene diisocyanate, and hydroxyethyl acrylate is 1:2:2. The aliphatic polyester polyurethane acrylate obtained under this raw material molar ratio has excellent UV resistance and anti-yellowing properties.

[0026] Furthermore, polybutadiene polyurethane acrylate is obtained by addition reaction of terminal hydroxyl polybutadiene and isophordine diisocyanate. In the present application, the polybutadiene polyurethane acrylate prepared by terminal hydroxyl polybutadiene and isophordine diisocyanate has the characteristics of low curing shrinkage, good flexibility, good adhesion, excellent hydrophobicity, etc.

[0027] Furthermore, the polyurethane acrylate prepolymer is a combination of aliphatic polyester polyurethane acrylate and polybutadiene polyurethane acrylate, and the mass ratio of the aliphatic polyester polyurethane acrylate to the polybutadiene polyurethane acrylate is 25:40.

[0028] Specifically, the LED display screen bracket is generally a PCB board, which has low surface energy, and the surface usually has residual solder resist, solder and other substances, which are difficult to bond. This application uses aliphatic polyester polyurethane acrylate, which has urethane bonds in the molecule, and can form multiple hydrogen bonds between polymer chains, so that the cured film has excellent flexibility and good adhesion. At the same time, the main chain of aliphatic polyester polyurethane is saturated alkane and cycloalkane, which is not easy to yellow and has excellent weather resistance. By using polybutadiene-modified polyurethane acrylate, many excellent properties of polybutadiene are retained, such as excellent low temperature resistance, and still maintain good elasticity and toughness in low temperature environment, and the prepared UV glue is not easy to fall off in low temperature environment. However, polybutadiene polyurethane acrylate has a special structure and will have certain compatibility problems. When used alone, its strength to the PCB board is not enough. Adding a certain proportion of aliphatic polyester polyurethane acrylate while ensuring the stability of the formula can improve the bonding strength of the glue. The polyurethane acrylate prepolymer combination in a specific proportion is selected as the main component of the UV glue, which can make the product have low curing shrinkage and flexibility while having good adhesion, yellowing resistance and weather resistance.

[0029] Furthermore, the acrylate active monomer is one or more of 2-(p-isopropylphenyl-phenoxy)-ethyl acrylate, 2-methyl-2-acrylate (tetrahydro-2-furanyl) methyl ester, ethylene glycol dicyclopentenyl ether acrylate, and propoxylated nonylphenol acrylate.

[0030] Preferably, the acrylate active monomer is a combination of 2-(p-isopropylphenyl-phenoxy)-ethyl acrylate, 2-methyl-2-acrylate (tetrahydro-2-furanyl) methyl ester, ethylene glycol dicyclopentenyl ether acrylate and propoxylated nonylphenol acrylate, and the mass ratio of 2-(p-isopropylphenyl-phenoxy)-ethyl acrylate, 2-methyl-2-acrylate (tetrahydro-2-furanyl) methyl ester, ethylene glycol dicyclopentenyl ether acrylate and propoxylated nonylphenol acrylate is 10:12:5:5.

[0031] In the present application, 2-(p-isopropylphenyl-phenoxy)-ethyl acrylate has a higher refractive index and lower water absorption, further reducing the water absorption of polyurethane acrylate prepolymer, improving weather resistance and environmental resistance, and being beneficial to long-term maintenance of packaging effect; 2-methyl-2-acrylic acid (tetrahydro-2-furanyl) methyl ester has good dilution, low hardness, good adhesion, low Tg and good bonding performance, enhancing the cohesion of the colloid and the adhesion to the PCB substrate, which is beneficial to the UV glue to maintain performance at low temperature or under certain mechanical stress environment; ethylene glycol dicyclopentenyl ether acrylate can improve yellowing resistance, and also contains flexible ether groups and rigid structures, which ensures the cross-linking effect while providing a certain flexibility, improves the hardness and has low shrinkage; propoxylated nonylphenol acrylate has low irritation and a slightly slow curing speed, but the polar groups therein can enhance the force of the colloid on the PCB substrate, and interact with the polar groups in the polyurethane, which can improve compatibility and ensure bonding performance.

[0032] Specifically, if the proportion of 2-(p-isopropylphenyl-phenoxy)-ethyl acrylate is too low, it will affect the water absorption rate of the glue, and if the proportion is too high, the odor will be strong, and the refractive index of other monomers is low. Continuing to increase its proportion will also reduce the transparency of the colloid; if the amount of 2-methyl-2-acrylate (tetrahydro-2-furanyl) methyl ester is too low, the flexibility is insufficient, and if it is too high, it will be more irritating and will also affect the hardness of the colloid; if the proportion of ethylene glycol dicyclopentenyl ether acrylate is too low, the performance enhancement is not obvious, and if the proportion is too high, the dilution is poor and the hardness of the colloid is increased; if the amount of propoxylated nonylphenol acrylate is too low, it will affect the effect of the colloid on the substrate, and if it is too high, it will affect the viscosity of the colloid. The present application uses a combination of acrylic acid ester active monomers with a suitable mass ratio, which is beneficial to improving the comprehensive performance of UV glue and ensuring good packaging adhesion effect.

[0033] Furthermore, the photoinitiator is one or two of 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide and 1-hydroxycyclohexyl phenyl ketone. Among them, the selected 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide has the characteristics of being colorless and low in yellowing after photolysis.

[0034] Furthermore, the rheological additive is a leveling agent BYK-333. By using the leveling agent BYK-333, it is beneficial to improve the coating leveling effect of the UV glue on the display screen.

[0035] The UV glue for GOB packaging of LED display screens provided in this application is a single-component glue with a curing time measured in seconds. Its adhesion and low-temperature resistance are better than those of epoxy AB glue, which greatly improves production efficiency. Moreover, after curing, its Shore hardness is between 50-90A. It also has good adhesion, weather resistance and flexibility, and is not easy to fall off.

[0036] The present application also provides a method for preparing the UV glue for GOB packaging of LED display screens as described above, which comprises the following steps: Add acrylate active monomer, photoinitiator and rheological additive into a container, heat to 40-50°C, and stir at 1200-1500 r / min for 20-30 min to mix; Add polyurethane acrylate prepolymer, heat to 50-60°C, stir at 1200-1800r / min for 30-50min to disperse, and obtain UV glue for GOB encapsulation of LED display screen.

[0037] The present application also provides an application of the UV glue for GOB encapsulation of LED display screens as described above, wherein the UV glue for GOB encapsulation of LED display screens is applied to the encapsulation of LED display screens, comprising the following steps: Prepare UV glue for GOB packaging of LED display screen, and then evenly apply it on the surface of LED display screen; Remove bubbles, and after the LED display GOB packaging is leveled with UV glue, coat the surface of the LED display and press it flat; Using an ultraviolet light surface light source to irradiate the LED display screen GOB packaging UV glue to completely cure; The excess glue around the edges is cut off to complete the packaging and obtain a packaged LED display.

[0038] The surface coating may be a PET film.

[0039] Furthermore, the power of the ultraviolet surface light source is 60W, the wavelength is 395nm, and the irradiation time is 15 seconds.

[0040] Further, the coating method includes one of roller coating, screen printing, and spraying; The method of removing bubbles includes one of standing or vacuuming. Among them, the bubbles generated in the gluing process are removed by standing or vacuuming to ensure the appearance performance.

[0041] Among them, the UV glue for LED display GOB packaging can be prepared by the above-mentioned preparation method.

[0042] The invention is further described below by means of specific examples.

[0043] The sources of some raw materials in the examples of this application are as follows: Polybutadiene polyurethane acrylate FSP5494: Guangzhou Runao Chemical Materials Co., Ltd.; Aliphatic polyester polyurethane acrylate DR-U331: Changxing Materials Industry (Guangdong) Co., Ltd.

[0044] Example 1 The UV glue for encapsulating the LED display screen GOB of Example 1 comprises the following raw materials in parts by mass: 25 parts of aliphatic polyester polyurethane acrylate DR-U331, 40 parts of polybutadiene polyurethane acrylate FSP5494, 10 parts of 2-(p-isopropylphenyl-phenoxy)-ethyl acrylate, 12 parts of 2-methyl-2-acrylic acid (tetrahydro-2-furanyl) methyl ester, 5 parts of ethylene glycol dicyclopentenyl ether acrylate, 5 parts of propoxylated nonylphenol acrylate, 1.9 parts of 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide, 1 part of 1-hydroxycyclohexyl-phenyl ketone, and 0.1 part of leveling agent BYK-333.

[0045] The method for preparing UV glue for GOB packaging of LED display screen of Example 1 comprises the following steps: Add 2-(p-isopropylphenyl-phenoxy)-ethyl acrylate, 2-methyl-2-acrylate (tetrahydro-2-furanyl) methyl ester, ethylene glycol dicyclopentenyl ether acrylate, propoxylated nonylphenol acrylate, 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide, 1-hydroxycyclohexyl-phenyl ketone and leveling agent BYK-333 in a container in proportion, heat to 50°C, and stir at 1500 r / min for 30 min to mix; Aliphatic polyester polyurethane acrylate DR-U331 and polybutadiene polyurethane acrylate FSP5494 were then added, and the mixture was heated to 60° C. and stirred at 1800 r / min for 50 min to disperse the mixture, thereby obtaining the UV adhesive for GOB encapsulation of the LED display screen of Example 1.

[0046] The UV glue for GOB packaging of LED display screen in Example 1 is applied to the packaging of LED display screen, comprising the following steps: Prepare the UV glue for GOB encapsulation of the LED display screen of Example 1, and evenly apply the UV glue for GOB encapsulation of the LED display screen of Example 1 on the surface of the LED display screen by roller coating; Vacuum to remove bubbles generated during the gluing process. After the LED display screen GOB encapsulation UV glue is leveled, cover the surface of the LED display screen with PET film and press it flat. The UV adhesive for GOB packaging of the LED display screen is completely cured by irradiating with an ultraviolet surface light source; the power of the ultraviolet surface light source is 60W, the wavelength is 395nm, and the irradiation time is 15 seconds.

[0047] The excess glue around the edges is cut off to complete the packaging and obtain a packaged LED display.

[0048] The performance of the UV glue for GOB packaging of the LED display screen in Example 1 was tested, and the packaging effect was as follows: Figure 1 The test items and test results are shown in Table 1: Table 1 project Basic standards / test conditions Standards achieved 1. Appearance standards Colorless or slightly yellow transparent / visual Colorless and transparent 2. Viscosity standard 1000-2000cps (25℃, 3#30) 1200cps 3. Curing conditions and standards 60W LED 395nm surface light source cures for 15 seconds, cumulative curing energy> 6000mj 60W LED 395nm surface light source cures completely in 15 seconds 4. Hardness standard 50-90A (GB / T 2411-2008) 60A 5. Peel strength (FR4 / PET) ≥10N (GBT 2792-2014) ≥20N 6. Yellowing test QUV UV light 168h no yellowing or low yellowing Low yellowing Among them, FR4 is an analog PCB board.

[0049] Example 2 The UV glue for encapsulating the LED display screen GOB of Example 2 includes the following raw materials in parts by mass: 65 parts of polybutadiene polyurethane acrylate FSP5494, 10 parts of 2-(p-isopropylphenyl-phenoxy)-ethyl acrylate, 12 parts of 2-methyl-2-acrylic acid (tetrahydro-2-furanyl) methyl ester, 5 parts of ethylene glycol dicyclopentenyl ether acrylate, 5 parts of propoxylated nonylphenol acrylate, 1.9 parts of 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide, 1 part of 1-hydroxycyclohexyl-phenyl ketone, and 0.1 part of leveling agent BYK-333.

[0050] The UV glue for GOB packaging of LED display screen of Example 2 was prepared by the same preparation method as Example 1.

[0051] Example 3 The UV glue for encapsulating the LED display screen GOB of Example 3 includes the following raw materials in parts by mass: Aliphatic polyester polyurethane acrylate DR-U331 25 parts, polybutadiene polyurethane acrylate FSP5494 40 parts, 2-(p-isopropylphenyl-phenoxy)-ethyl acrylate 10 parts, ethylene glycol dicyclopentenyl ether acrylate 17 parts, propoxylated nonylphenol acrylate 5 parts, 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide 1.9 parts, 1-hydroxycyclohexyl-phenyl ketone 1 part, leveling agent BYK-333 0.1 parts.

[0052] The UV glue for GOB packaging of LED display screen of Example 3 was prepared by the same preparation method as Example 1.

[0053] The performance test of the UV glue for GOB packaging of the LED display screen of Examples 1-3 was carried out, and the test items and test results are shown in Table 2: Table 2 project Example 1 Example 2 Example 3 1. Appearance Colorless and transparent Colorless and transparent Colorless and transparent 2. Viscosity 1200cps 1000cps 1800cps 3. Curing Comply with standards 20s Comply with standards 4. Hardness 60A 50A 90A 5. Peel strength (FR4 / PET) ≥20N ≥15N ≥15N 6. Yellowing Low yellowing Low yellowing Low yellowing The peel strength of the UV glue for GOB encapsulation of LED display screens prepared in Examples 1-3 all reached more than 10N, and it was not easy to fall off. After curing, the hardness was in the range of 50A-90A, taking into account the adhesion effect and a certain hardness, and effectively ensuring the encapsulation effect.

[0054] Comparative Example A commercially available brand of epoxy AB glue for GOB packaging of LED display screens was used as a comparative example.

[0055] The performance test of the epoxy AB glue of the comparative example was carried out, and the comparative test results are shown in Table 3: Table 3 project Example 1 Comparative Example 1. Hardness 60A 80D 2. Peel strength (FR4 / PET) ≥20N <5N By comparison, it can be found that the epoxy AB glue in the comparative example has a higher hardness and a lower peel strength, and is prone to falling off. However, the UV glue used for GOB packaging of the LED display screen in Example 1 of the present application has a peel strength of more than 20N and has a good adhesion effect.

[0056] The UV glue for GOB packaging of LED display screens provided in the embodiment of the present application is used as a single-component glue, and the curing time is measured in seconds. The adhesion and low-temperature resistance are better than those of epoxy AB glue, which can greatly improve the production efficiency. After curing, the Shore hardness is between 50-90A, with good adhesion, good weather resistance, and not easy to fall off.

[0057] It should be understood that the application of the present application is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made according to the above description, and all these improvements and changes should fall within the scope of protection of the present application.

Claims

1. A UV glue for LED display GOB packaging, characterized in that: According to the weight percentage, it includes the following raw materials: 55-65 parts of polyurethane acrylate prepolymer, 30-35 parts of acrylate active monomer, 2-5 parts of photoinitiator, and 0.1-0.5 parts of rheological additive.

2. The UV glue for encapsulating GOB of LED display screen according to claim 1, characterized in that: The polyurethane acrylate prepolymer is one or both of aliphatic polyester polyurethane acrylate and polybutadiene polyurethane acrylate.

3. The UV glue for encapsulating GOB of LED display screen according to claim 2, characterized in that: The polyurethane acrylate prepolymer is a combination of aliphatic polyester polyurethane acrylate and polybutadiene polyurethane acrylate, and the mass ratio of the aliphatic polyester polyurethane acrylate to the polybutadiene polyurethane acrylate is 25:40; The aliphatic polyester polyurethane acrylate is obtained by an addition reaction of polyester diol, hexamethylene diisocyanate and hydroxyethyl acrylate, wherein the molar ratio of the polyester diol, hexamethylene diisocyanate and hydroxyethyl acrylate is 1:2:2; The polybutadiene polyurethane acrylate is obtained by the addition reaction of terminal hydroxyl polybutadiene and isophordione diisocyanate.

4. The UV glue for LED display GOB packaging according to claim 1, characterized in that: The acrylic acid ester active monomer is one or more of 2-(p-isopropylphenyl-phenoxy)-ethyl acrylate, 2-methyl-2-acrylate (tetrahydro-2-furanyl) methyl ester, ethylene glycol dicyclopentenyl ether acrylate, and propoxylated nonylphenol acrylate.

5. The UV glue for encapsulating GOB of LED display screen according to claim 4, characterized in that: The acrylic acid ester active monomer is a combination of 2-(p-isopropylphenyl-phenoxy)-ethyl acrylate, 2-methyl-2-acrylate (tetrahydro-2-furanyl) methyl ester, ethylene glycol dicyclopentenyl ether acrylate, and propoxylated nonylphenol acrylate, and the mass ratio of the 2-(p-isopropylphenyl-phenoxy)-ethyl acrylate, 2-methyl-2-acrylate (tetrahydro-2-furanyl) methyl ester, ethylene glycol dicyclopentenyl ether acrylate, and propoxylated nonylphenol acrylate is 10:12:5:

5.

6. The UV glue for encapsulating GOB of LED display screen according to claim 1, characterized in that: The photoinitiator is one or two of 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide and 1-hydroxycyclohexyl phenyl ketone.

7. The UV glue for LED display GOB packaging according to claim 1, characterized in that: The rheological additive is the leveling agent BYK-333.

8. A method for preparing UV glue for GOB packaging of LED display screens according to any one of claims 1 to 7, characterized in that: The following steps are involved: Add acrylate active monomer, photoinitiator and rheological additive into a container, heat to 40-50°C, and stir at 1200-1500 r / min for 20-30 min to mix; Add polyurethane acrylate prepolymer, heat to 50-60° C., stir at 1200-1800 r / min for 30-50 min to disperse, and obtain the UV glue for GOB encapsulation of the LED display screen.

9. An application of UV glue for GOB packaging of LED display screens as claimed in any one of claims 1 to 7, characterized in that: Applying the UV glue for GOB packaging of LED display screen to the packaging of LED display screen includes the following steps: Prepare the UV glue for GOB packaging of the LED display screen, and then apply it on the surface of the LED display screen; Remove the bubbles, wait for the LED display screen GOB packaging to be leveled with UV glue, and then coat the surface of the LED display screen and press it flat; Using an ultraviolet light surface light source to irradiate the LED display screen GOB packaging UV glue to completely cure; Cut off the overflow glue around to get the packaged LED display; The coating method includes one of roller coating, screen printing and spraying; The method of removing bubbles includes one of leaving the mixture to stand or evacuating the mixture.

10. The application of UV glue for GOB packaging of LED display screen according to claim 9, characterized in that: The power of the ultraviolet surface light source is 60W, the wavelength is 395nm, and the irradiation time is 15 seconds.

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