UV (ultraviolet) viscosity-reducing adhesive as well as preparation method and application thereof

Abstract

The invention relates to a UV viscosity-reducing adhesive and a preparation method and application thereof, and belongs to the technical field of adhesive materials. The preparation method comprises the following steps: S1, adding a thermal initiator into an acrylic monomer in a solvent, and carrying out heating copolymerization to obtain a base glue solution; s2, adding a vinyl ether photoactive monomer and an acid catalyst into the base adhesive solution, and heating and grafting to obtain a photoactive pressure-sensitive adhesive solution; and S3, adding an initiator and an auxiliary agent into the photoactive pressure-sensitive adhesive solution, and uniformly mixing to obtain the UV viscosity-reducing adhesive. The UV viscosity-reducing adhesive is applied to the UV viscosity-reducing adhesive tape. According to the UV viscosity-reducing adhesive, acrylic acid-2-ethyl isocyanate is replaced with the acrylate monomer containing vinyl ether, the production cost of the UV viscosity-reducing adhesive is greatly reduced, the toxicity of the UV viscosity-reducing adhesive is reduced, the initial adhesion of the UV viscosity-reducing adhesive tape is high, the stripping force is rapidly reduced after UV irradiation, and the use requirement of the UV viscosity-reducing adhesive tape is met.

Description

Technical Field

[0001] This invention relates to a UV-resistant adhesive, its preparation method, and its application, belonging to the field of adhesive materials technology. Background Technology

[0002] UV-resistant adhesives, as a special type of adhesive, have been widely used in many fields in recent years. UV-resistant adhesives exhibit high adhesion before ultraviolet (UV) irradiation, but the adhesion decreases sharply after UV irradiation, making them a key material for meeting specific process requirements. With continuous technological advancements and increasingly stringent material performance requirements in industries such as semiconductors and optoelectronics, the research and application of UV-resistant adhesives have received increasing attention.

[0003] From a synthesis perspective, UV anti-tack adhesives are currently divided into two types: hybrid and non-hybrid. Non-hybrid adhesives are prepared by modifying the base adhesive obtained through thermal polymerization with acrylate. For example, patent application CN119351008A discloses a method for preparing UV anti-tack tape, which uses ethyl 2-isocyanate acrylate or ethyl isocyanate methacrylate as photoactive monomers. Photoactive groups are introduced by reacting the isocyanate groups with the hydroxyl groups on the polymerized molecular chain. Compared to hybrid adhesives, non-hybrid UV anti-tack adhesives have advantages such as higher cohesion, less residue, and more stable and uniform adhesive after curing. However, the currently used monomers, ethyl 2-isocyanate acrylate or ethyl isocyanate methacrylate, are both bifunctional photoactive monomers with strong irritant properties and relatively low boiling points (e.g., ethyl 2-isocyanate acrylate has a boiling point of only 82℃), causing many inconveniences in actual production and transportation. Furthermore, due to the demanding production process and patent protection, these two photoactive modifiers are currently quite expensive (only a few suppliers at Showa Chemical in Japan can provide them in large quantities). These factors contribute to the high cost of unmixed UV anti-tack adhesives. Therefore, it is of great significance to synthesize unmixed UV anti-tack adhesives using novel, low-toxicity, and cheaper photoactive modification methods. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a UV-resistant adhesive, its preparation method, and its application. The UV-resistant adhesive has low toxicity and low preparation cost. Furthermore, the UV-resistant adhesive tape produced by this adhesive has high initial tack and rapidly reduced peel strength after UV irradiation, resulting in better application performance.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: a method for preparing a UV anti-adhesive, wherein the preparation method is as follows: S1. In a solvent, acrylic monomers are copolymerized by adding a thermal initiator and heating to obtain a base adhesive solution. S2. Add vinyl ether photoactive monomers and acidic catalysts to the base adhesive solution, and perform heating grafting to obtain a photoactive pressure-sensitive adhesive solution. S3. After adding initiator and additives to the photoactive pressure-sensitive adhesive solution and mixing evenly, a UV-resistant adhesive is obtained.

[0006] Furthermore, in step S1, the acrylic monomers include hard monomers, soft monomers, and functionalized monomers; The mass ratio of the hard monomer, soft monomer and functionalized monomer is (1-3):(1-10):(1-5).

[0007] Furthermore, the hard monomer is selected from at least one of methyl acrylate, ethyl acrylate, and propyl acrylate; The soft monomer is selected from at least one of butyl acrylate, 2-ethylhexyl acrylate, and isooctyl acrylate; The functionalized monomer is selected from at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, and hydroxypropyl methacrylate.

[0008] Furthermore, in step S1, the thermal initiator is selected from at least one of azo initiators and peroxide initiators; The amount of thermal initiator added is 0.01%-0.5% of the total mass of the acrylic monomers.

[0009] Furthermore, in step S2, the vinyl ether photoactive monomer is 2-(2-ethoxyethoxy)ethyl acrylate; The amount of the vinyl ether photoactive monomer added is 10%-90% of the total mass of the acrylic monomer.

[0010] Furthermore, in step S2, the acidic catalyst is at least one of methanesulfonic acid, p-toluenesulfonic acid, solid polystyrene sulfonic acid, sulfuric acid, and boron trifluoride ether. The amount of acidic catalyst added is 1%-5% of the total mass of the acrylic monomers.

[0011] Furthermore, in step S1, the reaction temperature for heating copolymerization is 60-100℃; In step S2, the reaction temperature for heating the grafting is 20-100℃.

[0012] Furthermore, in step S3, the initiator is at least one selected from 1-hydroxycyclohexylphenyl ketone, benzophenone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and 2-hydroxy-2-methylphenylacetone. The auxiliary agent is at least one of γ-methacryloxypropyltrimethoxysilane and diisopropyl di(acetylacetonyl)titanate.

[0013] The present invention also discloses a UV-resistant adhesive, which is prepared by the preparation method described in the present invention.

[0014] The present invention also discloses an application of a UV anti-adhesion adhesive, wherein the UV anti-adhesion adhesive is applied in a UV anti-adhesion tape, and the UV anti-adhesion adhesive is coated on a substrate film to obtain a UV anti-adhesion tape.

[0015] The beneficial effects of this invention are: The UV anti-tack adhesive of this invention uses acrylate monomers containing vinyl ethers instead of ethyl 2-isocyanate, which greatly reduces the production cost of the UV anti-tack adhesive and also reduces its toxicity.

[0016] The UV-resistant tape prepared using the UV-resistant adhesive described in this invention exhibits high initial tack and a rapid decrease in peel strength after UV irradiation (minimum 0.10 N / 25 mm), meeting the requirements for use as a UV-resistant adhesive. At the same solid content, the UV-resistant tape of this invention has lower viscosity, satisfying more application processes such as spraying and roller coating; its structure offers better flexibility, imparting higher initial tack performance; and its lower peel strength after UV irradiation effectively avoids adhesive residue during use, resulting in superior performance. Furthermore, the preparation process is simple and suitable for industrial applications. Attached Figure Description

[0017] Figure 1 The infrared detection spectrum before the grafting reaction after the addition of VEEA in Example 1; Figure 2 The infrared detection spectrum after the addition of VEEA and the grafting reaction in Example 1 shows that the absorption peaks of vinyl ether (wavenumbers 1643.75 and 1616.67) are significantly weakened after the reaction. Figure 3 The infrared detection spectrum before the grafting reaction after adding VEEA in Example 2; Figure 4 The image shows the infrared spectrum of the vinyl ether after the addition of VEEA and the grafting reaction in Example 2. The absorption peaks of the vinyl ether (wavenumbers 1637.50 and 1618.75) were significantly weakened after the reaction. Detailed Implementation

[0018] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described in detail below. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0020] A method for preparing a UV-resistant adhesive, wherein the preparation method comprises: S1. In a solvent, acrylic monomers are copolymerized by adding a thermal initiator and heating to obtain a base adhesive solution. S2. Add vinyl ether photoactive monomers and acidic catalysts to the base adhesive solution, and perform heating grafting to obtain a photoactive pressure-sensitive adhesive solution. S3. After adding initiator and additives to the photoactive pressure-sensitive adhesive solution and mixing evenly, a UV-resistant adhesive is obtained.

[0021] Specifically, in step S1, the acrylic monomers include hard monomers, soft monomers, and functionalized monomers; The mass ratio of the hard monomer, soft monomer and functionalized monomer is (1-3):(1-10):(1-5).

[0022] Specifically, the hard monomer is selected from at least one of methyl acrylate, ethyl acrylate, and propyl acrylate; The soft monomer is selected from at least one of butyl acrylate, 2-ethylhexyl acrylate, and isooctyl acrylate; The functionalized monomer is selected from at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, and hydroxypropyl methacrylate.

[0023] Specifically, in step S1, the thermal initiator is selected from at least one of azo initiators and peroxide initiators; The amount of thermal initiator added is 0.01%-0.5% of the total mass of the acrylic monomers.

[0024] More specifically, in step S1, the thermal initiator is selected from at least one of azobisisobutyronitrile (AIBN), azobisisobutyronitrile, benzoyl peroxide, and dodecyl peroxide.

[0025] Preferably, in step S1, the thermal initiator is azobisisobutyronitrile or benzoyl peroxide.

[0026] Preferably, the amount of thermal initiator added is 0.1% of the total mass of the acrylic monomers.

[0027] Specifically, in step S2, the vinyl ether photoactive monomer is 2-(2-ethoxyethoxy)ethyl acrylate (VEEA). The amount of the vinyl ether photoactive monomer added is 10%-90% of the total mass of the acrylic monomer.

[0028] Preferably, the amount of the vinyl ether photoactive monomer added is 50% of the total mass of the acrylic monomer.

[0029] Specifically, in step S2, the acidic catalyst is at least one of methanesulfonic acid, p-toluenesulfonic acid, solid polystyrene sulfonic acid (CAS: 28210-41-5), sulfuric acid, and boron trifluoride ether. The amount of acidic catalyst added is 1%-5% of the total mass of the acrylic monomers.

[0030] Preferably, in step S2, the acidic catalyst is solid polystyrene sulfonic acid (CAS: 28210-41-5).

[0031] Specifically, in step S1, the reaction temperature for heating copolymerization is 60-100℃; In step S2, the reaction temperature for heating the grafting is 20-100℃.

[0032] Preferably, in step S1, the reaction temperature for heating copolymerization is 80°C; In step S2, the reaction temperature for heating the grafting is 60°C.

[0033] Specifically, in step S2, the grafting reaction time is 1-8 h, preferably 3-5 h.

[0034] Specifically, in step S3, the initiator is at least one of 1-hydroxycyclohexylphenyl ketone (Irgacure 184), benzophenone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), and 2-hydroxy-2-methylphenylacetone (1173).

[0035] Specifically, the auxiliary agent is at least one of γ-methacryloxypropyltrimethoxysilane and diisopropyl di(acetylacetonyl)titanate.

[0036] Specifically, the solvent is ethyl acetate.

[0037] More specifically, after the heating grafting reaction is completed, the solid catalyst is removed by filtration, and the solid content of the photoactive pressure-sensitive adhesive solution is 35%-45% (mass content).

[0038] Preferably, the solid content of the photoactive pressure-sensitive adhesive solution is 40% (by mass).

[0039] More specifically, the amount of initiator added is 1%-10% of the mass of the photoactive pressure-sensitive adhesive solution; the amount of additive added is 0.1%-1% of the mass of the photoactive pressure-sensitive adhesive solution.

[0040] Preferably, the amount of the initiator added is 2% of the mass of the photoactive pressure-sensitive adhesive solution; and the amount of the additive added is 0.3% of the mass of the photoactive pressure-sensitive adhesive solution.

[0041] A UV-resistant adhesive, wherein the UV-resistant adhesive is prepared by the preparation method described in this invention.

[0042] An application of a UV anti-tack adhesive, wherein the UV anti-tack adhesive is applied in a UV anti-tack tape, and the UV anti-tack adhesive is coated on a substrate film to obtain the UV anti-tack tape.

[0043] I. Preparation Examples of UV Anti-adhesive Example 1 A method for preparing a UV-resistant adhesive specifically includes the following steps: (1) Add n-propyl acrylate (20g, 175.22 mmol), butyl acrylate (60g, 468.13 mmol), hydroxyethyl acrylate (20g, 172.24 mmol), and ethyl acetate (100g, solvent) to a 500 mL four-necked round-bottom flask equipped with a reflux condenser, a mechanical stirrer, and a thermometer. Continuously purge the solution with nitrogen gas and heat the reaction solution to 80°C. Then, under a nitrogen atmosphere, slowly add azobisisobutyronitrile (0.1g, 0.1% of the mass of acrylic acid monomer) diluted in ethyl acetate (50g) dropwise to the round-bottom flask. Stir for 6 hours and cool to room temperature to terminate the reaction, obtaining the base gel solution.

[0044] (2) First, place the base adhesive solution (50g, solid content 40%) obtained in step (1) and solid polystyrene sulfonic acid (0.6g) into a 250mL round-bottom flask equipped with a mechanical stirrer. Then, dissolve 2-(2-ethyleneoxyethoxy)ethyl acrylate (6.4g, 34.48mmol) in ethyl acetate (9.6g) and slowly add it dropwise to the round-bottom flask. After stirring the reaction mixture at 60℃ for 3h, the reaction is terminated when the reaction mixture cools to room temperature. Infrared spectroscopy indicates that the modification is complete (e.g., Figure 1 and Figure 2 As shown, the characteristic absorption of vinyl groups at wavenumbers of 1643.75 and 1616.67 was significantly reduced after modification. The solid polystyrene benzenesulfonic acid catalyst was removed by filtration, and the final solid content was adjusted to 40% to obtain a photoactive pressure-sensitive adhesive solution.

[0045] (3) Add 2% by weight of 1-hydroxycyclohexylphenyl ketone and 0.3% by weight of γ-methacryloyloxypropyltrimethoxysilane to the photoactive pressure-sensitive adhesive solution in step (2) and mix to obtain UV anti-tack adhesive.

[0046] Example 2 A method for preparing a UV-resistant adhesive specifically includes the following steps: (1) Add methyl acrylate (30g, 232.31mmol), 2-ethylhexyl acrylate (60g, 325.59mmol), hydroxyethyl acrylate (20g, 172.24mmol), and ethyl acetate (110g, solvent) to a 500mL four-necked round-bottom flask equipped with a reflux condenser, a mechanical stirrer, and a thermometer. Continuously purge the solution with nitrogen gas and heat the reaction solution to 80°C. Then, under a nitrogen atmosphere, slowly add azobisisobutyronitrile (0.11g, 0.1% of the mass of acrylic monomer) diluted in ethyl acetate (55g) to the round-bottom flask. Stir for 8 h and cool to room temperature to terminate the reaction, obtaining the base gel solution.

[0047] (2) First, place the base adhesive solution (50g, solid content 40%) obtained in step (1) and solid polystyrene sulfonic acid (0.6g) into a 250mL round-bottom flask equipped with a mechanical stirrer. Then, dissolve 2-(2-ethyleneoxyethoxy)ethyl acrylate (2.9g, 15.65mmol) in ethyl acetate (7.3g) and slowly add it dropwise to the round-bottom flask. After stirring the reaction at 60℃ for 5 h, stop the reaction when the reaction mixture cools to room temperature. Infrared spectroscopy indicates that the modification is complete (e.g., Figure 3 and Figure 4 As shown, the characteristic absorption of vinyl groups at wavenumbers of 1635.42 and 1618.75 was significantly reduced after modification. The solid polystyrene benzenesulfonic acid catalyst was removed by filtration, and the final solid content was adjusted to 40% to obtain a photoactive pressure-sensitive adhesive solution.

[0048] (3) Add 2% by weight of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and 0.3% by weight of γ-methacryloyloxypropyltrimethoxysilane to the photoactive pressure-sensitive adhesive solution in step (2) and mix to obtain UV anti-tack adhesive.

[0049] Example 3 A method for preparing a UV-resistant adhesive specifically includes the following steps: (1) Add ethyl acrylate (30 g, 299.64 mmol), isooctyl acrylate (50 g, 271.33 mmol), hydroxypropyl acrylate (20 g, 153.68 mmol), and ethyl acetate (100 g, solvent) to a 500 mL four-necked round-bottom flask equipped with a reflux condenser, a mechanical stirrer, and a thermometer. Continuously purge the solution with nitrogen gas and heat the reaction solution to 80 °C. Then, under a nitrogen atmosphere, slowly add benzoyl peroxide (0.2 g, 0.2% of the mass of acrylic acid monomer) diluted in ethyl acetate (50 g) dropwise to the round-bottom flask. Stir for 8 h and cool to room temperature to terminate the reaction, obtaining the base gel solution.

[0050] (2) First, put the base adhesive solution (50g, solid content 40%) obtained in step (1) and solid polystyrene sulfonic acid (0.6g) into a 250mL round-bottom flask equipped with a mechanical stirrer. Then, dissolve 2-(2-ethyleneoxyethoxy)ethyl acrylate (2.8g, 15.37mmol) in ethyl acetate (4.3g) and slowly add it dropwise into the round-bottom flask. After stirring the reaction at 60℃ for 6 h, the reaction was terminated after the reaction mixture cooled to room temperature. The solid polystyrene benzenesulfonic acid catalyst was removed by filtration. The final solid content was adjusted to 40% to obtain a photoactive pressure-sensitive adhesive solution. (3) Add 2% by weight of 2-hydroxy-2-methylphenylacetone (1173) and 0.3% by weight of γ-methacryloyloxypropyltrimethoxysilane to the photoactive pressure-sensitive adhesive solution in step (2) and mix to obtain UV anti-tack adhesive.

[0051] Example 4 A method for preparing a UV-resistant adhesive specifically includes the following steps: (1) Add ethyl acrylate (30g, 299.64 mmol), isooctyl acrylate (50g, 271.33 mmol), hydroxyethyl methacrylate (20g, 153.68 mmol), and ethyl acetate (100g, solvent) to a 500 mL four-necked round-bottom flask equipped with a reflux condenser, a mechanical stirrer, and a thermometer. Continuously purge the solution with nitrogen gas and heat the reaction solution to 80°C. Then, under a nitrogen atmosphere, slowly add benzoyl peroxide (0.2g, 0.2wt% acrylic acid monomer) diluted in ethyl acetate (50g) dropwise to the round-bottom flask. Stir for 10 h and cool to room temperature to terminate the reaction, obtaining the base gel solution.

[0052] (2) First, put the base adhesive solution (50g, 40wt% solution) obtained in step (1) and solid polystyrene sulfonic acid (0.6g) into a 250mL round-bottom flask equipped with a mechanical stirrer. Then, dissolve 2-(2-ethyleneoxyethoxy)ethyl acrylate (2.8g, 15.37 mmol) in ethyl acetate (4.3g) and slowly add it dropwise into the round-bottom flask. After stirring the reaction at 60℃ for 4 h, the reaction was terminated after the reaction mixture cooled to room temperature. The solid polystyrene benzenesulfonic acid catalyst was removed by filtration. The final solid content was adjusted to 40% to obtain a photoactive pressure-sensitive adhesive solution. (3) Add 2% by weight of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and 0.3% by weight of γ-methacryloyloxypropyltrimethoxysilane to the photoactive pressure-sensitive adhesive solution in step (2) and mix to obtain UV anti-tack adhesive. Comparative Example 1 The UV anti-adhesive was prepared using the same method as in Example 1, except that in step (2) of Comparative Example 1, the same molar amount of ethyl 2-isocyanate was used instead of ethyl 2-(2-ethyleneoxyethoxy)ethyl acrylate, and a catalyst suitable for the reaction of ethyl 2-isocyanate, dibutyltin dilaurate, was used. The specific process is as follows: (1) Add n-propyl acrylate (20g, 175.22 mmol), butyl acrylate (60g, 468.13 mmol), hydroxyethyl acrylate (20g, 172.24 mmol), and ethyl acetate (100g, solvent) to a 500 mL four-necked round-bottom flask equipped with a reflux condenser, a mechanical stirrer, and a thermometer. Continuously purge the solution with nitrogen gas and heat the reaction solution to 80°C. Then, under a nitrogen atmosphere, slowly add azobisisobutyronitrile (0.1g, 0.1% of the mass of acrylic acid monomer) diluted in ethyl acetate (50g) dropwise to the round-bottom flask. Stir for 6 h and cool to room temperature to terminate the reaction, obtaining the base gel solution.

[0053] (2) First, put the base adhesive solution (50g, solid content 40%) obtained in step (1) and dibutyltin dilaurate (5 mg) into a 250mL round-bottom flask equipped with a mechanical stirrer. Then, dissolve ethyl 2-isocyanate (4.87 g, 34.48 mmol) in ethyl acetate (9.6 g) and slowly add it dropwise into the round-bottom flask. After stirring the reaction at 60℃ for 3 h, the reaction was terminated when the reaction mixture cooled to room temperature. The infrared display showed that NCO disappeared (wavenumber 2272). The final solid content was adjusted to 40%, and the photoactive pressure-sensitive adhesive solution was obtained.

[0054] (3) Add 2% by weight of 1-hydroxycyclohexylphenyl ketone and 0.3% by weight of γ-methacryloyloxypropyltrimethoxysilane to the photoactive pressure-sensitive adhesive solution in step (2) and mix to obtain UV anti-tack adhesive.

[0055] II. Application and Performance Testing of UV Anti-tack Tape (1) The UV anti-tack adhesive in the examples and comparative examples was coated onto a PET film with a thickness of 50 μm using a 60 μm wire bar coater. After pre-baking in an oven at 50°C for 25 min to remove solvent, it was then cured at 25°C for 12 h to form a UV anti-tack adhesive layer on the surface of the substrate layer (PET film).

[0056] (2) A PET release film with a thickness of 50 μm is applied to the UV anti-tack adhesive layer, and then cured at 25°C for 7 days to form a release film layer on the surface of the UV anti-tack adhesive layer, thus obtaining the UV anti-tack tape.

[0057] (3) UV peel strength test: Cut the UV anti-adhesion tape into 250×20mm samples, remove the release film, and bond the sample to the cleaned 304 stainless steel plate. Use a 2kg pressure roller to roll back and forth on the sample three times at a speed of 300mm / min under its own weight (no air bubbles are allowed at the bonding point between the sample and the test plate). After the sample is prepared, stop for 30 minutes in the test environment and then conduct the test. Use a tape peel strength tester (Dongguan Kejian, model: KJ-1065) to conduct the peel test under the conditions of 180° angle and 300mm / min to obtain the UV peel strength.

[0058] (4) UV peel strength test: Cut the UV anti-tack tape into 300×25mm samples, remove the release film, and bond the sample to the cleaned 304 stainless steel plate. Use a 2kg roller to roll back and forth on the sample three times at a speed of 300mm / min under its own weight (no air bubbles are allowed at the bonding point between the sample and the test plate). The UV anti-tack tape is then subjected to a UV pressure of 200mJ / cm. 2 After being treated under light intensity for 5 minutes, the tape peel strength tester (Dongguan Kejian, model: KJ-1065) was used at an angle of 180 degrees. o Peel tests were conducted at a tensile speed of 300 mm / min to obtain the peel strength after UV exposure. After peeling, the surface of the 304 stainless steel plate was observed to determine whether there was any adhesive residue, and the results of the adhesive residue test were obtained.

[0059] (5) Initial tack test of tape (before UV): Cut the UV anti-adhesion tape into 300×25mm samples, remove the release film, bend it into a ring with the adhesive side facing outwards, suspend it on the clamp of a tensile testing machine, and lower it at a speed of 300 mm / min. The adhesive side contacts the surface of the horizontally placed stainless steel plate below and forms an adhesive bond by its own weight. After the adhesive area reaches 25mm × 25mm, stop lowering and hold for 30 seconds. Then, the clamp of the tensile testing machine rises at 300mm / min and records the maximum force required for peeling, in N.

[0060] (6) Brookfield viscosity test: Viscosity testing instrument: Brookfield DV-2T; Test conditions: temperature 25℃, rotation speed 10r / min, rotor #2.

[0061] The performance test results are shown in Table 1 below.

[0062] Table 1 Performance Test Results As can be seen from the data in the table above, the UV-resistant adhesive tapes prepared using the method described in Examples 1-4 exhibit high peel strength before UV irradiation, which rapidly decreases after UV exposure. Furthermore, due to the presence of fewer polar functional groups in the structure (ethyl 2-isocyanate, as a photoactive monomer, reacts with the base adhesive to form a urethane structure, which still exhibits strong van der Waals forces at the bonding interface even after UV curing and tack reduction, resulting in greater peel strength after UV irradiation), the peel strength after UV tack reduction is generally lower than that of Comparative Example 1, with the lowest peel strength as low as 0.10 N / 25 mm. Additionally, because the molecular structure does not contain urethane structures, the resulting adhesive film has better flexibility, thus exhibiting better wetting ability on the substrate during initial tack testing, resulting in higher initial tack. The UV-resistant adhesive tapes described in this invention demonstrate significantly superior performance compared to the conventional UV-resistant adhesives in the comparative examples.

[0063] Comparing the experimental results of Comparative Example 1 and Example 1, the present invention uses ethyl acrylate-2-(2-ethyleneoxyethoxy)ethyl acrylate graft modification to prepare UV anti-tack adhesive, which has better performance. Moreover, compared with ethyl acrylate-2-isocyanate used in Comparative Example 1, ethyl acrylate-2-(2-ethyleneoxyethoxy)ethyl acrylate has lower toxicity as a photoactive raw material, is more convenient to produce and transport, and has lower cost. The product has excellent performance and is more suitable for industrial promotion and application.

[0064] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0065] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing a UV-resistant adhesive, characterized in that, The preparation method is as follows: S1. In a solvent, acrylic monomers are copolymerized by adding a thermal initiator and heating to obtain a base adhesive solution. S2. Add vinyl ether photoactive monomers and acidic catalysts to the base adhesive solution, and perform heating grafting to obtain a photoactive pressure-sensitive adhesive solution. S3. After adding initiator and additives to the photoactive pressure-sensitive adhesive solution and mixing evenly, a UV-resistant adhesive is obtained.

2. The method for preparing a UV-resistant adhesive according to claim 1, characterized in that, In step S1, the acrylic monomers include hard monomers, soft monomers, and functionalized monomers; The mass ratio of the hard monomer, soft monomer and functionalized monomer is (1-3):(1-10):(1-5).

3. The method for preparing a UV-resistant adhesive according to claim 2, characterized in that, The hard monomer is selected from at least one of methyl acrylate, ethyl acrylate, and propyl acrylate; The soft monomer is selected from at least one of butyl acrylate, 2-ethylhexyl acrylate, and isooctyl acrylate; The functionalized monomer is selected from at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, and hydroxypropyl methacrylate.

4. The method for preparing a UV-resistant adhesive according to claim 1, characterized in that, In step S1, the thermal initiator is selected from at least one of azo initiators and peroxide initiators; The amount of thermal initiator added is 0.01%-0.5% of the total mass of the acrylic monomers.

5. The method for preparing a UV-resistant adhesive according to claim 1, characterized in that, In step S2, the vinyl ether photoactive monomer is 2-(2-ethoxyethoxy)ethyl acrylate; The amount of the vinyl ether photoactive monomer added is 10%-90% of the total mass of the acrylic monomer.

6. The method for preparing a UV-resistant adhesive according to claim 1, characterized in that, In step S2, the acidic catalyst is at least one of methanesulfonic acid, p-toluenesulfonic acid, solid polystyrene sulfonic acid, sulfuric acid, and boron trifluoride ether. The amount of acidic catalyst added is 1%-5% of the total mass of the acrylic monomers.

7. The method for preparing a UV-resistant adhesive according to claim 1, characterized in that, In step S1, the reaction temperature for heating copolymerization is 60-100℃; In step S2, the reaction temperature for heating the grafting is 20-100℃.

8. The method for preparing a UV-resistant adhesive according to claim 1, characterized in that, In step S3, the initiator is at least one of 1-hydroxycyclohexylphenyl ketone, benzophenone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and 2-hydroxy-2-methylphenylacetone; The auxiliary agent is at least one of γ-methacryloxypropyltrimethoxysilane and diisopropyl di(acetylacetonyl)titanate.

9. A UV-resistant adhesive, characterized in that, The UV-resistant adhesive is prepared by the preparation method described in any one of claims 1-8.

10. An application of the UV-resistant adhesive according to claim 9, characterized in that, The UV anti-tack adhesive is used in UV anti-tack tape, which is prepared by coating the UV anti-tack adhesive onto a substrate film.

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