Bio-based UV viscosity-reducing adhesive tape and manufacturing method thereof

Abstract

The invention discloses a manufacturing method of a bio-based UV viscosity-reducing adhesive tape. The manufacturing method specifically comprises the following steps: step 1, preparing styrene modified cardanol; step 2, preparing diphenylethylene modified cardiotonic acid; step 3, preparing styrene modified salicylic acid; step 4, preparing styrene modified cinnamic acid; 5, preparing a surface treating agent according to products obtained in the steps 1-3; step 6, preparing a substance-based UV-cured adhesive according to products obtained in the steps 1-4; and step 7, taking a polyurethane film as an adhesive tape base material, firstly coating a layer of surface treating agent on the upper surface of the adhesive tape base material for surface treatment, then continuously coating a layer of UV cured adhesive on the adhesive tape base subjected to surface treatment, and drying to obtain the bio-based UV viscosity-reducing adhesive tape. The invention further discloses the bio-based UV viscosity-reducing adhesive tape. The problem that an existing adhesive tape is difficult to have high viscosity and easy-to-peel performance at the same time is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of bio-based polymer new materials, relates to a bio-based UV release tape, and also relates to a method for manufacturing the bio-based UV release tape. Background Art

[0002] Functional release tapes are widely used in the fields of electronic component fixation and wafer cutting. However, when using the tape, it not only needs to have good adhesiveness, but also be easily peeled off after use without affecting the appearance or cleanliness of the adherend. Therefore, there should be no glue residue after the tape is peeled off. For this reason, a series of thermal expansion release tapes have been developed, that is, a thermal expansion agent is added to the adhesive. Under heating conditions, the adhesiveness of the tape decreases and it can be peeled off. However, heating easily damages the adherend. UV (ultraviolet light curing) release tapes can achieve non-destructive peeling. In order to improve the initial adhesiveness of the UV release tape, acrylic units are usually introduced into the adhesive. However, acrylic acid has strong acidity and is easy to corrode the adherend. And there is glue residue when the tape is peeled off. From the perspective of microscopic molecules, it is because the intermolecular force is weak when the tape is peeled off and the molecular center of gravity shifts. The principle of traditional UV release tapes is usually that UV irradiation induces the decomposition of the adhesive, and the adhesiveness decreases to achieve release. However, after the decomposition of the adhesive, it is easy to leave residue when the tape is peeled off. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for manufacturing a bio-based UV release tape. The tape manufactured by this method solves the problem that existing tapes are difficult to simultaneously have high adhesiveness and easy peeling performance.

[0004] Another purpose of the present invention is to provide a bio-based UV release tape.

[0005] The first technical solution adopted by the present invention is a method for manufacturing a bio-based UV release tape, which specifically includes the following steps: Step 1, prepare styrene-modified cardanol; Step 2, prepare bis-styrene-modified strong acid; Step 3, prepare styrene-modified salicylic acid; Step 4, prepare styrene-modified cinnamic acid; Step 5, prepare a surface treatment agent according to the products obtained in Steps 1-3; Step 6, prepare a bio-based UV-curable adhesive according to the products obtained in Steps 1-4; Step 7, take a polyurethane film as the tape substrate. First, coat a layer of surface treatment agent on the upper surface of the tape substrate for surface treatment. Subsequently, on the tape substrate that has undergone surface treatment, continue to coat a layer of UV-curable adhesive, and obtain a bio-based UV release tape after drying treatment.

[0006] The characteristics of the first technical solution of the present invention also lie in: The specific process of Step 1 is as follows: Dissolve cardanol in N,N-dimethylformamide solution, then add a certain amount of potassium carbonate, stir at room temperature for 10 - 20 min, then place the reaction flask in an ice-water bath, and then dropwise add 4-vinylbenzyl chloride. After the addition is completed, raise the temperature to room temperature and continue the reaction for 2 - 4 h. After the reaction is completed, directly pour the reaction solution into deionized water to obtain a light yellow solid. Wash the light yellow solid three times with deionized water, and dry the solid at 40 - 50 o °C for 12 - 24 h to obtain styrene-modified cardanol; wherein, the molar ratio of cardanol: potassium carbonate: 4-vinylbenzyl chloride is 1:1:1.

[0007] The specific process of Step 2 is as follows: Add N,N-dimethylformamide solution to the reaction flask. Dissolve strong acid in N,N-dimethylformamide solution, add potassium carbonate, and stir at room temperature for 10 - 20 min; then place the reaction flask in an ice-water bath, and then dropwise add 4-vinylbenzyl chloride. After the addition is completed, raise the temperature to room temperature and continue the reaction for 2 - 4 h. After the reaction is completed, directly pour the reaction solution into deionized water to obtain a light yellow solid. Wash the solid three times with deionized water, and dry the solid at 40 - 50 o °C for 12 - 24 h to obtain bis-styrene-modified strong acid; wherein, the molar ratio of strong acid: potassium carbonate: 4-vinylbenzyl chloride is 1:2:2.

[0008] In Step 2, the strong acid is 5-(octadecyl-8-enyl)benzene-1,3-diol.

[0009] The specific process of Step 3 is as follows: Step 3.1: Add salicylic acid to methanol solution, then add H2SO4, stir at room temperature for 8 - 12 min. After the reaction is completed, spin-dry the reaction solution and purify it by column chromatography separation technology to obtain colorless methyl salicylate; Step 3.2: Add N,N-dimethylformamide solution to the reaction flask. Dissolve the methyl salicylate prepared in Step 3.1 in N,N-dimethylformamide solution, add potassium carbonate, and stir at room temperature for 10 - 20 min; then place the reaction flask in an ice-water bath, and then dropwise add 4-vinylbenzyl chloride. After the addition is completed, raise the temperature to room temperature and continue the reaction for 2 - 4 h; after the reaction is completed, directly pour the reaction solution into deionized water to obtain a light yellow solid. Wash the solid three times with deionized water, and dry the solid at 40 - 50 o °C for 12 - 24 h to obtain styrene-modified methyl salicylate; Step 3.3: Dissolve the styrene-modified methyl salicylate obtained in Step 3.2 in an N,N-dimethylformamide solution, add deionized water and sodium hydroxide, stir at room temperature for 5 - 10 h, then add a HCl solution to adjust the pH of the reaction solution to neutral, and continue to stir at room temperature for 1 - 2 h; Subsequently, directly pour the obtained reaction solution into deionized water, white solids will precipitate out, and filter to obtain styrene-modified salicylic acid.

[0010] The specific process of Step 4 is as follows: Dissolve cinnamic acid in a toluene solution, then add sodium methoxide, and stir at room temperature for 30 - 60 min; continue to add 4-vinylbenzyl chloride and tetrabutylammonium bromide to the reaction system, and the heating rate is 5 - 10 o °C per hour; After the reaction is completed, perform vacuum drying using an oil pump to obtain styrene-modified cinnamic acid, where the molar ratio of cinnamic acid:sodium methoxide:4-vinylbenzyl chloride:tetrabutylammonium bromide is 1:1:1:0.01.

[0011] The specific process of Step 5 is as follows: Take styrene-modified cardanol, bis-styrene-modified strong acid, styrene-modified salicylic acid, acrylic acid, and N-hydroxyethyl acrylamide and disperse them in a toluene solution. Then add azobisisobutyronitrile, raise the temperature to 60 - 70 o °C, control the product viscosity at 10000 - 15000 cps, and immediately stop heating; After the temperature drops to room temperature, add p-methoxyphenol to obtain a surface treatment agent.

[0012] The specific process of Step 6 is as follows: Take styrene-modified cardanol, bis-styrene-modified strong acid, styrene-modified salicylic acid, allyl isocyanate, styrene-modified cinnamic acid, and 2-[2-(2-methoxyethoxy)ethoxy]ethyl acrylate and disperse them in a toluene solution; Then add azobisisobutyronitrile, raise the temperature to 60 - 70 o °C, control the product viscosity at 10000 - 15000 cps, and immediately stop heating; After the temperature drops to room temperature, add p-methoxyphenol to obtain a bio-based UV-curable adhesive.

[0013] In Step 7, the coating thickness of the surface treatment agent is 5 - 10 um, and the surface treatment process is as follows: Place the tape substrate in an oven at 40 - 50 o °C for 20 - 40 min; The coating thickness of the UV-curable adhesive is 30 - 50 um, and the drying treatment process is as follows: Place the surface-treated tape substrate in an oven at 40 - 50 o °C for 40 - 80 min to obtain the bio-based UV-debonding tape.

[0014] The second technical solution adopted by the present invention is a bio-based UV pressure-sensitive adhesive tape, which is prepared by using the above-mentioned method for preparing a bio-based UV pressure-sensitive adhesive tape.

[0015] The beneficial effects of the present invention are as follows: The present invention designs a novel bio-based UV pressure-sensitive adhesive tape, in which styrene-modified cashew phenol and styrene-modified salicylic acid are introduced into the adhesive, which not only improves the initial adhesiveness and acid corrosion resistance of the tape. And the double-styrene-modified strong acid has a bifunctional group structure and, as a cross-linking agent, effectively reduces the adhesive residue when the tape is peeled off. By utilizing the presence of the cinnamic acid structure in the adhesive, under UV irradiation, cyclization cross-linking (volume shrinkage) occurs to achieve pressure-sensitive adhesive reduction of the tape. Description of the Drawings

[0016] Figure 1 Schematic diagram of the tape structure prepared by the method for preparing a bio-based UV pressure-sensitive adhesive tape of the present invention; Figure 2 Comparison chart of the initial adhesiveness and the adhesiveness after UV curing of Examples 1-3 and Comparative Examples 1-7 of the method for preparing a bio-based UV pressure-sensitive adhesive tape of the present invention. Detailed Description of the Invention

[0017] The following is a detailed description in conjunction with the specific embodiments.

[0018] The method for preparing a bio-based UV pressure-sensitive adhesive tape of the present invention specifically includes the following steps: Step 1, prepare styrene-modified cashew phenol, specifically: Take a certain amount of cashew phenol and dissolve it in 30 - 60 mL of N,N-dimethylformamide solution, then add a certain amount of potassium carbonate, and stir at room temperature for 10 - 20 min. Then, place the reaction flask in an ice-water bath, and then dropwise add a certain amount of 4-vinylbenzyl chloride (the dropping time is 20 - 40 min). After the dropping is completed, raise the temperature to room temperature and continue the reaction for 2 - 4 h. After the reaction is completed, directly pour the reaction solution into 200 - 600 mL of deionized water at 0 o C to obtain a light yellow solid. Wash the light yellow solid three times with 200 - 600 mL of deionized water, and dry the solid at 40 - 50 o C for 12 - 24 h to obtain styrene-modified cashew phenol. The molar ratio of cashew phenol: potassium carbonate: 4-vinylbenzyl chloride is 1:1:1. The molar amount of cashew phenol is 0.01 - 0.03 mol; The synthesis route of styrene-modified cashew phenol is as follows:

[0019] Step 2, prepare double-styrene-modified strong acid, specifically: Add an N,N-dimethylformamide solution to the reaction flask. Take a certain amount of strong acid (5-(octadec-8-enyl)benzene-1,3-diol), dissolve it in 30 - 60 mL of the N,N-dimethylformamide solution, then add a certain amount of potassium carbonate, and stir at room temperature for 10 - 20 min. Then, place the reaction flask in an ice-water bath, and subsequently add dropwise a certain amount of 4-vinylbenzyl chloride (the dropping time is 20 - 40 min). After the dropping is completed, raise the temperature to room temperature and continue the reaction for 2 - 4 h. After the reaction is completed, directly pour the reaction solution into 200 - 600 mL of deionized water at 0 o °C to obtain a pale yellow solid. The solid is further washed three times with 200 - 600 mL of deionized water, and the solid is dried at 40 - 50 o °C for 12 - 24 h to obtain the styrene-modified strong acid.

[0020] The molar ratio of strong acid : potassium carbonate : 4-vinylbenzyl chloride is 1:2:2. The molar amount of strong acid is 0.01 - 0.03 mol. The synthesis route of the styrene-modified strong acid is as follows:

[0021] Step 3, prepare the styrene-modified salicylic acid, specifically: Step 3.1, take a certain amount of salicylic acid and add it to 30 - 60 mL of methanol solution, then add 0.2 - 0.4 mL of H2SO4, stir at room temperature for 8 - 12 min. After the reaction is completed, spin-dry the reaction solution and purify it using column chromatography separation technology (the stationary phase is silica gel, and the mobile phase is n-hexane and chloroform, where v:v = 10:1) to obtain colorless methyl salicylate.

[0022] Step 3.2, take the methyl salicylate prepared in Step 3.1, dissolve it in 30 - 60 mL of the N,N-dimethylformamide solution contained in the reaction flask, then add a certain amount of potassium carbonate, and stir at room temperature for 10 - 20 min. Then, place the reaction flask in an ice-water bath, and subsequently add dropwise a certain amount of 4-vinylbenzyl chloride (the dropping time is 20 - 40 min). After the dropping is completed, raise the temperature to room temperature and continue the reaction for 2 - 4 h. After the reaction is completed, directly pour the reaction solution into 200 - 600 mL of deionized water at 0 o °C to obtain a pale yellow solid. The solid is further washed three times with 200 - 600 mL of deionized water, and the solid is dried at 40 - 50 o °C for 12 - 24 h to obtain the styrene-modified methyl salicylate; Step 3.3: Dissolve the methyl salicylate modified by styrene obtained in Step 3.2 in 20 - 40 mL of N,N - dimethylformamide solution, then add 20 - 40 mL of deionized water and a certain amount of sodium hydroxide, and stir at room temperature for 5 - 10 h. Then, slowly add the HCl solution with a mass fraction of 30% to adjust the pH of the reaction solution to 7, and continue to stir at room temperature for 1 - 2 h. Subsequently, directly pour the obtained reaction solution into 200 - 600 mL of deionized water at 0 o °C, and white solid will precipitate. Filter directly to obtain styrene - modified salicylic acid.

[0023] The molar ratio of salicylic acid, potassium carbonate, 4 - vinylbenzyl chloride, and sodium hydroxide is 1:1:1:1. The molar amount of salicylic acid is 0.01 - 0.03 mol. The specific synthesis route of styrene - modified salicylic acid is as follows:

[0024] Step 4: Prepare styrene - modified cinnamic acid, specifically: Take a certain amount of cinnamic acid and dissolve it in 30 - 60 mL of toluene solution, then add a certain amount of sodium methoxide, and stir at room temperature for 30 - 60 min. Continue to add a certain amount of 4 - vinylbenzyl chloride and tetrabutylammonium bromide to the reaction system. The temperature is slowly raised from 25 o °C to 85 o °C at a heating rate of 5 - 10 o °C per hour. After the reaction is completed, perform vacuum drying (-0.06~ - 0.08 MPa) using an oil pump to obtain styrene - modified cinnamic acid. The molar ratio of cinnamic acid:sodium methoxide:4 - vinylbenzyl chloride:tetrabutylammonium bromide is 1:1:1:0.01. The molar amount of cinnamic acid is 0.01 - 0.03 mol. The synthesis route of styrene - modified cinnamic acid is as follows:

[0025] Step 5: Prepare the surface treatment agent, specifically: Take a certain amount of styrene - modified cardanol, bis - styrene - modified strong acid, styrene - modified salicylic acid, acrylic acid, and N - hydroxyethyl acrylamide and disperse them in 10 - 20 mL of toluene solution. Then add 10 - 20 mg of azobisisobutyronitrile, raise the temperature to 60 - 70 o °C, and control the product viscosity at 10000 - 15000 cps, then immediately stop heating. After the temperature drops to room temperature, add 5 - 10 mg of p - methoxyphenol to obtain the surface treatment agent. In the above process, 5 - 10 g of styrene - modified cardanol, 0.2 - 0.4 g of bis - styrene - modified strong acid, 2 - 4 g of styrene - modified salicylic acid, 1 - 2 g of acrylic acid, and 2 - 4 g of N - hydroxyethyl acrylamide are used.

[0026] Step 6, prepare a bio-based UV-curable adhesive, specifically: Take a certain amount of styrene-modified cardanol, bis-styrene-modified strong acid, styrene-modified salicylic acid, allyl isocyanate, styrene-modified cinnamic acid, and 2-[2-(2-methoxyethoxy)ethoxy]ethyl acrylate and disperse them in 10 - 20 mL of toluene solution. Then add 10 - 20 mg of azobisisobutyronitrile, and raise the temperature to 60 - 70 o °C, control the product viscosity at 10000 - 15000 cps, and immediately stop heating. After the temperature drops to room temperature, add 5 - 10 mg of p-methoxy phenol to obtain a bio-based UV-curable adhesive.

[0027] In the above process, 5 - 10 g of styrene-modified cardanol, 0.2 - 0.4 g of bis-styrene-modified strong acid, 5 - 10 g of styrene-modified salicylic acid, 1 - 2 g of allyl isocyanate, 3 - 6 g of styrene-modified cinnamic acid, and 5 - 10 g of 2-[2-(2-methoxyethoxy)ethoxy]ethyl acrylate are used.

[0028] Step 7, prepare a bio-based UV release tape, specifically: As Figure 1 shown, select a polyurethane film (25 g / m 2 ) as the tape substrate. First, coat a layer of surface treatment agent on the upper surface of the tape substrate, with a coating thickness of 5 - 10 μm, and then place the tape substrate in an oven at 40 - 50 o °C for 20 - 40 min. For the surface-treated substrate, continue to coat a layer of UV-curable adhesive with a coating thickness of 30 - 50 μm, and then place the obtained tape substrate in an oven at 40 - 50 o °C for 40 - 80 min to obtain a bio-based UV release tape.

[0029] Example 1 Step 1, prepare styrene-modified cardanol, specifically: Take 3.02 g of cardanol (molar amount of 0.01 mol), dissolve it in 30 mL of N,N-dimethylformamide solution, and then add 1.38 g of potassium carbonate and stir at room temperature for 10 min. Then, place the reaction flask in an ice-water bath, and then dropwise add 1.53 g of 4-vinylbenzyl chloride (the dropping time is 20 min). After the dropping is completed, raise the temperature to room temperature and continue the reaction for 2 h. After the reaction is completed, directly pour the reaction solution into 200 mL of deionized water at 0 o °C to obtain a pale yellow solid. The solid is further washed three times with 200 mL of deionized water, and the solid is dried at 40 o °C for 12 h to obtain styrene-modified cardanol.

[0030] Step 2, prepare styrene-modified strong acid, specifically as follows: Add 30 mL of N,N-dimethylformamide solution to a reaction flask. Take 3.18 g of strong acid 5-(octadecyl-8-enyl)benzene-1,3-diol (the molar amount of the strong acid is 0.01 mol) and dissolve it in the N,N-dimethylformamide solution. Then add 2.76 g of potassium carbonate and stir at room temperature for 10 min. Then, place the reaction flask in an ice-water bath, and then dropwise add 3.06 g of 4-vinylbenzyl chloride (the dropping time is 20 min). After the dropping is completed, raise the temperature to room temperature and continue the reaction for 2 h. After the reaction is completed, directly pour the reaction solution into 200 mL of deionized water at 0 o °C to obtain a pale yellow solid. The solid is further washed three times with 200 mL of deionized water, and the solid is dried at 40 o °C for 12 h to obtain styrene-modified strong acid.

[0031] Step 3, prepare styrene-modified salicylic acid, specifically as follows: Step 3.1, take 1.38 g of salicylic acid (the molar amount of salicylic acid is 0.01 mol), add it to 30 mL of methanol solution, and then add 0.2 mL of H2SO4. Stir at room temperature for 8 min. After the reaction is completed, spin-dry the reaction solution and then purify it by column chromatography separation technology (the stationary phase is silica gel, and the mobile phase is n-hexane and chloroform, where v:v = 10:1) to obtain colorless methyl salicylate; Step 3.2, take the methyl salicylate prepared in Step 3.1 and dissolve it in 30 mL of N,N-dimethylformamide solution in a reaction flask. Then add 1.38 g of potassium carbonate and stir at room temperature for 10 min. Then, place the reaction flask in an ice-water bath, and then dropwise add 1.53 g of 4-vinylbenzyl chloride (the dropping time is 20 min). After the dropping is completed, raise the temperature to room temperature and continue the reaction for 2 h. After the reaction is completed, directly pour the reaction solution into 200 mL of deionized water at 0 o °C to obtain a pale yellow solid. The solid is further washed three times with 200 mL of deionized water, and the solid is dried at 40 o °C for 12 h to obtain styrene-modified methyl salicylate; Step 3.3, dissolve the styrene-modified methyl salicylate obtained in Step 3.2 in 20 mL of N,N-dimethylformamide solution, then add 20 mL of deionized water and 0.4 g of sodium hydroxide, and stir at room temperature for 5 h. Then dropwise add a 30% HCl solution to adjust the pH of the reaction solution to 7, and continue to stir at room temperature for 1 h. Subsequently, directly pour the obtained reaction solution into 200 mL of deionized water at 0 oIn deionized water of C, white solids precipitated, and styrene-modified salicylic acid was directly obtained by filtration.

[0032] Step 4: Prepare styrene-modified cinnamic acid, specifically: Take 1.48 g of cinnamic acid (the molar amount of cinnamic acid is 0.01 mol), dissolve it in 30 mL of toluene solution, then add 0.54 g of sodium methoxide, and stir at room temperature for 30 min. Continue to add 1.53 g of 4-vinylbenzyl chloride and 0.032 g of tetrabutylammonium bromide to the reaction system, and the temperature is slowly raised from 25 o C to 85 o C at a heating rate of 5 o C per hour. After the reaction is completed, vacuum drying (-0.06 MPa) is carried out using an oil pump to obtain styrene-modified cinnamic acid.

[0033] Step 5: Prepare a surface treatment agent, specifically: Take 5 g of styrene-modified cardanol, 0.2 g of bis-styrene-modified strong acid, 2 g of styrene-modified salicylic acid, 1 g of acrylic acid, and 2 g of N-hydroxyethyl acrylamide and disperse them in 10 mL of toluene solution. Then add 10 mg of azobisisobutyronitrile, raise the temperature to 60 o C, and control the product viscosity at 10000 - 15000 cps, and immediately stop heating. After the temperature drops to room temperature, add 5 mg of p-hydroxyanisole to obtain the surface treatment agent.

[0034] Step 6: Prepare a bio-based UV-curable adhesive, specifically: Take 5 g of styrene-modified cardanol, 0.2 g of bis-styrene-modified strong acid, 5 g of styrene-modified salicylic acid, 1 g of allyl isocyanate, 3 g of styrene-modified cinnamic acid, and 5 g of 2-[2-(2-methoxyethoxy)ethoxy]ethyl acrylate and disperse them in 10 mL of toluene solution. Then add 10 mg of azobisisobutyronitrile, raise the temperature to 60 o C, and control the product viscosity at 10000 - 15000 cps, and immediately stop heating. After the temperature drops to room temperature, add 5 mg of p-hydroxyanisole to obtain the bio-based UV-curable adhesive.

[0035] Step 7: Prepare a bio-based UV pressure-sensitive adhesive tape, specifically: Select a polyurethane film (25 g / m 2 ) as the tape substrate. First, coat a layer of surface treatment agent on the upper surface of the substrate, with a coating thickness of 5 um, and then place the substrate in a 40 o C oven for 20 min. For the surface-treated substrate, continue to coat a layer of UV-curable adhesive, with a coating thickness of 30 um, and then place the obtained tape in a 40 oPlace it in an oven at 40 °C for 40 min to obtain the bio-based UV tack-reducing tape.

[0036] Example 2 Step 1: Prepare styrene-modified cardanol, specifically as follows: Take 9.06 g of cardanol (the molar amount of cardanol is 0.03 mol), dissolve it in 60 mL of N,N-dimethylformamide solution, then add 4.14 g of potassium carbonate, and stir at room temperature for 20 min. Then, place the reaction flask in an ice-water bath, and then dropwise add 4.59 g of 4-vinylbenzyl chloride (the dropping time is 40 min). After the dropping is completed, raise the temperature to room temperature and continue the reaction for 4 h. After the reaction is completed, directly pour the reaction solution into 600 mL of deionized water at 0 o °C to obtain a pale yellow solid. The solid is washed three times with 600 mL of deionized water, and the solid is dried at 50 o °C for 24 h to obtain styrene-modified cardanol.

[0037] Step 2: Prepare bis-styrene-modified strong acid, specifically as follows: Add 60 mL of N,N-dimethylformamide solution to the reaction flask. Take 9.54 g of strong acid 5-(octadecyl-8-enyl)benzene-1,3-diol (the molar amount of strong acid is 0.03 mol) and dissolve it in the N,N-dimethylformamide solution, then add 8.28 g of potassium carbonate, and stir at room temperature for 20 min. Then, place the reaction flask in an ice-water bath, and then dropwise add 9.18 g of 4-vinylbenzyl chloride (the dropping time is 40 min). After the dropping is completed, raise the temperature to room temperature and continue the reaction for 4 h. After the reaction is completed, directly pour the reaction solution into 600 mL of deionized water at 0 o °C to obtain a pale yellow solid. The solid is washed three times with 600 mL of deionized water, and the solid is dried at 50 o °C for 24 h to obtain bis-styrene-modified strong acid.

[0038] Step 3: Prepare styrene-modified salicylic acid, specifically as follows: Step 3.1: Take 4.14 g of salicylic acid (the molar amount of salicylic acid is 0.03 mol) and add it to 60 mL of methanol solution, then add 0.4 mL of H2SO4, and stir at room temperature for 12 min. After the reaction is completed, spin-dry the reaction solution and then purify it by column chromatography separation technology (the stationary phase is silica gel, and the mobile phase is n-hexane and chloroform, where v:v = 10:1) to obtain colorless methyl salicylate.

[0039] Step 3.2: Charge 60 mL of N,N-dimethylformamide solution into a reaction flask. Dissolve the methyl salicylate prepared in Step 3.1 in the N,N-dimethylformamide solution, then add 4.14 g of potassium carbonate, and stir at room temperature for 20 min. Then, place the reaction flask in an ice-water bath, and subsequently add dropwise 4.59 g of 4-vinylbenzyl chloride (the dropping time is 40 min). After the dropping is completed, raise the temperature to room temperature and continue the reaction for 4 h. After the reaction is completed, directly pour the reaction solution into 600 mL of deionized water at 0 o °C to obtain a pale yellow solid. The solid is further washed three times with 600 mL of deionized water, and the solid is dried at 50 o °C for 24 h to obtain styrene-modified methyl salicylate.

[0040] Step 3.3: Dissolve the styrene-modified methyl salicylate obtained in Step 3.2 in 40 mL of N,N-dimethylformamide solution, then add 40 mL of deionized water and 1.2 g of sodium hydroxide, and stir at room temperature for 10 h. Then, add dropwise a 30% HCl solution to adjust the pH of the reaction solution to 7, and continue stirring at room temperature for 2 h. Subsequently, directly pour the obtained reaction solution into 600 mL of deionized water at 0 o °C, and white solid precipitates. Filter directly to obtain styrene-modified salicylic acid.

[0041] Step 4: Prepare styrene-modified cinnamic acid, specifically: Take 4.44 g of cinnamic acid (the molar amount of cinnamic acid is 0.03 mol), dissolve it in 60 mL of toluene solution, then add 1.62 g of sodium methoxide, and stir at room temperature for 60 min. Continue to add 4.59 g of 4-vinylbenzyl chloride and 0.096 g of tetrabutylammonium bromide to the reaction system. The temperature is slowly raised from 25 o °C to 85 o °C at a heating rate of 10 o °C per hour. After the reaction is completed, perform vacuum drying (-0.08 MPa) using an oil pump to obtain styrene-modified cinnamic acid.

[0042] Step 5: Prepare a surface treatment agent, specifically: Take 10 g of styrene-modified cardanol, 0.4 g of bis-styrene-modified strong acid, 4 g of styrene-modified salicylic acid, 2 g of acrylic acid, and 4 g of N-hydroxyethyl acrylamide and disperse them in 20 mL of toluene solution. Then add 20 mg of azobisisobutyronitrile, raise the temperature to 70 o °C, control the product viscosity at 10000 - 15000 cps, and immediately stop heating. After the temperature drops to room temperature, add 10 mg of p-methoxy phenol to obtain a surface treatment agent.

[0043] Step 6, prepare a bio-based UV-curable adhesive, specifically as follows: Take 10 g of styrene-modified cardanol, 0.4 g of bis-styrene-modified strong acid, 10 g of styrene-modified salicylic acid, 2 g of allyl isocyanate, 6 g of styrene-modified cinnamic acid, and 10 g of 2-[2-(2-methoxyethoxy)ethoxy]ethyl acrylate and disperse them in 20 mL of toluene solution. Then add 20 mg of azobisisobutyronitrile and raise the temperature to 70 o °C, control the product viscosity at 10,000 - 15,000 cps, and immediately stop heating. After the temperature drops to room temperature, add 10 mg of p-hydroxyanisole to obtain a bio-based UV-curable adhesive.

[0044] Step 7, prepare a bio-based UV pressure-sensitive adhesive tape, specifically as follows: Select a polyurethane film (25 g / m 2 ) as the tape substrate. First, coat a surface treatment agent on the upper surface of the tape substrate with a coating thickness of 10 μm, and then place the substrate in a 50 o °C oven for 40 min. For the surface-treated substrate, continue to coat a layer of UV-curable adhesive with a coating thickness of 50 μm, and then place the obtained tape in a 50 o °C oven for 80 min to obtain a bio-based UV pressure-sensitive adhesive tape.

[0045] Example 3 Step 1, prepare styrene-modified cardanol, specifically as follows: Take 6.04 g of cardanol (the molar amount of cardanol is 0.02 mol), dissolve it in 45 mL of N,N-dimethylformamide solution, and then add 2.76 g of potassium carbonate and stir at room temperature for 15 min. Then, place the reaction flask in an ice-water bath, and then dropwise add 3.06 g of 4-vinylbenzyl chloride (the dropping time is 30 min). After the dropping is completed, raise the temperature to room temperature and continue the reaction for 3 h. After the reaction is completed, directly pour the reaction solution into 400 mL of deionized water at 0 o °C to obtain a pale yellow solid. The solid is washed three times with 400 mL of deionized water, and the solid is dried at 45 o °C for 18 h to obtain styrene-modified cardanol.

[0046] Step 2, prepare bis-styrene-modified strong acid, specifically as follows: Add 45 mL of N,N-dimethylformamide solution to the reaction flask. Take 6.36 g of 5-(octadec-8-enyl)benzene-1,3-diol strong acid (the molar amount of the strong acid is 0.02 mol) and dissolve it in the N,N-dimethylformamide solution. Then add 5.52 g of potassium carbonate and stir at room temperature for 15 min. Then, place the reaction flask in an ice-water bath, and then dropwise add 6.12 g of 4-vinylbenzyl chloride (the dropping time is 30 min). After the dropping is completed, raise the temperature to room temperature and continue the reaction for 3 h. After the reaction is completed, pour the reaction solution directly into 400 mL of deionized water at 0 o °C to obtain a pale yellow solid. The solid is further washed three times with 400 mL of deionized water, and the solid is dried at 45 o °C for 18 h to obtain the double styrene-modified strong acid.

[0047] Step 3: Prepare styrene-modified salicylic acid, specifically as follows: Step 3.1: Take 2.76 g of salicylic acid (the molar amount of salicylic acid is 0.02 mol), add it to 45 mL of methanol solution, and then add 0.3 mL of H2SO4. Stir at room temperature for 10 min. After the reaction is completed, the reaction solution is rotary evaporated and then purified by column chromatography separation technology (the stationary phase is silica gel, and the mobile phase is n-hexane and chloroform, where v:v = 10:1) to obtain colorless methyl salicylate.

[0048] Step 3.2: Take the methyl salicylate prepared in Step 3.1 and dissolve it in 45 mL of N,N-dimethylformamide solution in the reaction flask. Then add 2.76 g of potassium carbonate and stir at room temperature for 15 min. Then, place the reaction flask in an ice-water bath, and then dropwise add 3.06 g of 4-vinylbenzyl chloride (the dropping time is 30 min). After the dropping is completed, raise the temperature to room temperature and continue the reaction for 3 h. After the reaction is completed, pour the reaction solution directly into 400 mL of deionized water at 0 o °C to obtain a pale yellow solid. The solid is further washed three times with 400 mL of deionized water, and the solid is dried at 45 o °C for 18 h to obtain styrene-modified methyl salicylate.

[0049] Step 3.3: Dissolve the styrene-modified methyl salicylate obtained in Step 3.2 in 30 mL of N,N-dimethylformamide solution, then add 30 mL of deionized water and 0.8 g of sodium hydroxide, and stir at room temperature for 7.5 h. Then dropwise add a 30% HCl solution to adjust the pH of the reaction solution to 7, and continue to stir at room temperature for 1.5 h. Subsequently, pour the obtained reaction solution directly into 400 mL of deionized water at 0 o °C, and white solid precipitates. Filter directly to obtain styrene-modified salicylic acid.

[0050] Step 4: Prepare styrene-modified cinnamic acid, specifically as follows: Take 2.96 g of cinnamic acid (the molar amount of cinnamic acid is 0.02 mol), dissolve it in 45 mL of toluene solution, then add 1.08 g of sodium methoxide, and stir at room temperature for 45 min. Continue to add 3.06 g of 4-vinylbenzyl chloride and 0.064 g of tetrabutylammonium bromide to the reaction system. The temperature is slowly raised from 25 o °C to 85 o °C at a heating rate of 7.5 o °C per hour. After the reaction is completed, vacuum drying (-0.07 MPa) is carried out using an oil pump to obtain styrene-modified cinnamic acid.

[0051] Step 5: Prepare a surface treatment agent, specifically as follows: Take 7.5 g of styrene-modified cashew phenol, 0.3 g of bis-styrene-modified strong acid, 3 g of styrene-modified salicylic acid, 1.5 g of acrylic acid, and 3 g of N-hydroxyethyl acrylamide and disperse them in 15 mL of toluene solution. Then add 15 mg of azobisisobutyronitrile, raise the temperature to 65 o °C, and control the product viscosity at 10000 - 15000 cps, and immediately stop heating. After the temperature drops to room temperature, add 7.5 mg of p-methoxy phenol to obtain a surface treatment agent.

[0052] Step 6: Prepare a bio-based UV-curable adhesive, specifically as follows: Take 7.5 g of styrene-modified cashew phenol, 0.3 g of bis-styrene-modified strong acid, 7.5 g of styrene-modified salicylic acid, 1.5 g of allyl isocyanate, 4.5 g of styrene-modified cinnamic acid, and 7.5 g of 2-[2-(2-methoxyethoxy)ethoxy]ethyl acrylate and disperse them in 15 mL of toluene solution. Then add 15 mg of azobisisobutyronitrile, raise the temperature to 65 o °C, and control the product viscosity at 10000 - 15000 cps, and immediately stop heating. After the temperature drops to room temperature, add 8 mg of p-methoxy phenol to obtain a bio-based UV-curable adhesive.

[0053] Step 7: Prepare a bio-based UV pressure-sensitive adhesive tape, specifically as follows: Select a polyurethane film (25 g / m 2 ) as the tape substrate. First, coat a layer of surface treatment agent on the upper surface of the tape substrate, with a coating thickness of 7.5 μm, and then place the substrate in a 45 o °C oven for 30 min. For the tape substrate after surface treatment, continue to coat a layer of UV-curable adhesive, with a coating thickness of 40 μm, and then place the obtained tape in a 45 oPlace it in a C oven for 60 min to obtain the bio-based UV tack-reducing tape.

[0054] Comparative Example 1 (N-hydroxyethyl acrylamide is not added to the surface treatment agent, and the adhesive layer and the surface treatment layer are easily peeled off, and there is glue residue when the tape is peeled off) Step 1: Prepare styrene-modified cardanol, specifically: Take 3.02 g of cardanol (molar amount is 0.01 mol), dissolve it in 30 mL of N,N-dimethylformamide solution, then add 1.38 g of potassium carbonate, and stir at room temperature for 10 min. Then, place the reaction flask in an ice-water bath, and then dropwise add 1.53 g of 4-vinylbenzyl chloride (the dropping time is 20 min). After the dropping is completed, the temperature is raised to room temperature and the reaction continues for 2 h. After the reaction is completed, pour the reaction solution directly into 200 mL of 0 o C deionized water to obtain a pale yellow solid. The solid is washed three times with 200 mL of deionized water, and the solid is dried at 40 o C for 12 h to obtain styrene-modified cardanol.

[0055] Step 2: Prepare bis-styrene-modified strong acid, specifically: Add 30 mL of N,N-dimethylformamide solution to the reaction flask. Take 3.18 g of strong acid 5-(octadecyl-8-enyl)benzene-1,3-diol (the molar amount of strong acid is 0.01 mol) and dissolve it in the N,N-dimethylformamide solution, then add 2.76 g of potassium carbonate, and stir at room temperature for 10 min. Then, place the reaction flask in an ice-water bath, and then dropwise add 3.06 g of 4-vinylbenzyl chloride (the dropping time is 20 min). After the dropping is completed, the temperature is raised to room temperature and the reaction continues for 2 h. After the reaction is completed, pour the reaction solution directly into 200 mL of 0 o C deionized water to obtain a pale yellow solid. The solid is washed three times with 200 mL of deionized water, and the solid is dried at 40 o C for 12 h to obtain bis-styrene-modified strong acid.

[0056] Step 3: Prepare styrene-modified salicylic acid, specifically: Step 3.1: Take 1.38 g of salicylic acid (the molar amount of salicylic acid is 0.01 mol), add it to 30 mL of methanol solution, then add 0.2 mL of H2SO4, and stir at room temperature for 8 min. After the reaction is completed, the reaction solution is dried by rotary evaporation and purified by column chromatography separation technology (the stationary phase is silica gel, and the mobile phase is n-hexane and chloroform, where v:v = 10:1) to obtain colorless methyl salicylate; Step 3.2, Take the methyl salicylate prepared in Step 3.1, dissolve it in 30 mL of N,N-dimethylformamide solution in a reaction flask, then add 1.38 g of potassium carbonate, and stir at room temperature for 10 min. Then, place the reaction flask in an ice-water bath, and then dropwise add 1.53 g of 4-vinylbenzyl chloride (the dropping time is 20 min). After the dropping is completed, the temperature is raised to room temperature, and the reaction continues for 2 h. After the reaction is completed, pour the reaction solution directly into 200 mL of deionized water at 0 o °C to obtain a pale yellow solid. The solid is further washed three times with 200 mL of deionized water, and the solid is dried at 40 o °C for 12 h to obtain styrene-modified methyl salicylate; Step 3.3, Dissolve the styrene-modified methyl salicylate obtained in Step 3.2 in 20 mL of N,N-dimethylformamide solution, then add 20 mL of deionized water and 0.4 g of sodium hydroxide, and stir at room temperature for 5 h. Then, dropwise add a 30% HCl solution to adjust the pH of the reaction solution to 7, and continue to stir at room temperature for 1 h. Subsequently, pour the obtained reaction solution directly into 200 mL of deionized water at 0 o °C, and white solid precipitates. Filter directly to obtain styrene-modified salicylic acid.

[0057] Step 4, Prepare styrene-modified cinnamic acid, specifically: Take 1.48 g of cinnamic acid (the molar amount of cinnamic acid is 0.01 mol), dissolve it in 30 mL of toluene solution, then add 0.54 g of sodium methoxide, and stir at room temperature for 30 min. Continue to add 1.53 g of 4-vinylbenzyl chloride and 0.032 g of tetrabutylammonium bromide to the reaction system. The temperature is slowly raised from 25 o °C to 85 o °C at a heating rate of 5 o °C per hour. After the reaction is completed, perform vacuum drying (-0.06 MPa) using an oil pump to obtain styrene-modified cinnamic acid.

[0058] Step 5, Prepare a surface treatment agent, specifically: Take 5 g of styrene-modified cashew phenol, 0.2 g of bis-styrene-modified strong acid, 2 g of styrene-modified salicylic acid, 1 g of acrylic acid, and 2 g of methyl acrylate, and disperse them in 10 mL of toluene solution. Then add 10 mg of azobisisobutyronitrile, raise the temperature to 60 o °C, control the product viscosity at 10000 - 15000 cps, and immediately stop heating. After the temperature drops to room temperature, add 5 mg of p-methoxy phenol to obtain a surface treatment agent.

[0059] Step 6, Prepare a bio-based UV-curable adhesive, specifically: Disperse 5 g of styrene-modified cardanol, 0.2 g of bis-styrene-modified strong acid, 5 g of styrene-modified salicylic acid, 1 g of allyl isocyanate, 3 g of styrene-modified cinnamic acid, and 5 g of 2-[2-(2-methoxyethoxy)ethoxy]ethyl acrylate in 10 mL of toluene solution. Then add 10 mg of azobisisobutyronitrile and raise the temperature to 60 o °C, control the product viscosity at 10,000 - 15,000 cps, and immediately stop heating. After the temperature drops to room temperature, add 5 mg of p-hydroxyanisole to obtain a bio-based UV-curable adhesive.

[0060] Step 7, prepare a bio-based UV pressure-sensitive adhesive tape, specifically: Select a polyurethane film (25 g / m 2 ²) as the tape substrate. First, coat a surface treatment agent on the upper surface of the substrate with a coating thickness of 5 μm, and then place the substrate in a 40 o °C oven for 20 min. For the surface-treated substrate, continue to coat a layer of UV-curable adhesive with a coating thickness of 30 μm, and then place the obtained tape in a 40 o °C oven for 40 min to obtain a bio-based UV pressure-sensitive adhesive tape.

[0061] Comparative Example 2 (No allyl isocyanate is added to the bio-based UV-curable adhesive, the adhesive layer is easy to peel off from the substrate, and there is glue residue when the tape is peeled off) Step 1, prepare styrene-modified cardanol, specifically: Take 3.02 g of cardanol (molar amount of 0.01 mol), dissolve it in 30 mL of N,N-dimethylformamide solution, and then add 1.38 g of potassium carbonate and stir at room temperature for 10 min. Then, place the reaction flask in an ice-water bath, and then dropwise add 1.53 g of 4-vinylbenzyl chloride (the dropping time is 20 min). After the dropping is completed, raise the temperature to room temperature and continue the reaction for 2 h. After the reaction is completed, directly pour the reaction solution into 200 mL of 0 o °C deionized water to obtain a light yellow solid. The solid is further washed three times with 200 mL of deionized water, and the solid is dried at 40 o °C for 12 h to obtain styrene-modified cardanol.

[0062] Step 2, prepare bis-styrene-modified strong acid, specifically: Add 30 mL of N,N-dimethylformamide solution to the reaction flask. Take 3.18 g of 5-(octadec-8-enyl)benzene-1,3-diol strong acid (the molar amount of the strong acid is 0.01 mol) and dissolve it in the N,N-dimethylformamide solution. Then add 2.76 g of potassium carbonate and stir at room temperature for 10 min. Then, place the reaction flask in an ice-water bath, and subsequently dropwise add 3.06 g of 4-vinylbenzyl chloride (the dropping time is 20 min). After the dropping is completed, raise the temperature to room temperature and continue the reaction for 2 h. After the reaction is completed, directly pour the reaction solution into 200 mL of deionized water at 0 o °C to obtain a pale yellow solid. The solid is further washed three times with 200 mL of deionized water, and the solid is dried at 40 o °C for 12 h to obtain styrene-modified strong acid.

[0063] Step 3: Prepare styrene-modified salicylic acid, specifically as follows: Step 3.1: Take 1.38 g of salicylic acid (the molar amount of salicylic acid is 0.01 mol), add it to 30 mL of methanol solution, and then add 0.2 mL of H2SO4. Stir at room temperature for 8 min. After the reaction is completed, spin-dry the reaction solution and purify it by column chromatography separation technology (the stationary phase is silica gel, and the mobile phase is n-hexane and chloroform, where v:v = 10:1) to obtain colorless methyl salicylate; Step 3.2: Take the methyl salicylate prepared in Step 3.1 and dissolve it in 30 mL of N,N-dimethylformamide solution in the reaction flask. Then add 1.38 g of potassium carbonate and stir at room temperature for 10 min. Then, place the reaction flask in an ice-water bath, and subsequently dropwise add 1.53 g of 4-vinylbenzyl chloride (the dropping time is 20 min). After the dropping is completed, raise the temperature to room temperature and continue the reaction for 2 h. After the reaction is completed, directly pour the reaction solution into 200 mL of deionized water at 0 o °C to obtain a pale yellow solid. The solid is further washed three times with 200 mL of deionized water, and the solid is dried at 40 o °C for 12 h to obtain styrene-modified methyl salicylate; Step 3.3: Dissolve the styrene-modified methyl salicylate obtained in Step 3.2 in 20 mL of N,N-dimethylformamide solution, then add 20 mL of deionized water and 0.4 g of sodium hydroxide, and stir at room temperature for 5 h. Then dropwise add 30% HCl solution to adjust the pH of the reaction solution to 7, and continue to stir at room temperature for 1 h. Subsequently, directly pour the obtained reaction solution into 200 mL of deionized water at 0 o °C, and white solid precipitates. Filter directly to obtain styrene-modified salicylic acid.

[0064] Step 4: Prepare styrene-modified cinnamic acid, specifically as follows: Take 1.48 g of cinnamic acid (the molar amount of cinnamic acid is 0.01 mol), dissolve it in 30 mL of toluene solution, then add 0.54 g of sodium methoxide, and stir at room temperature for 30 min. Continue to add 1.53 g of 4-vinylbenzyl chloride and 0.032 g of tetrabutylammonium bromide to the reaction system. The temperature is slowly raised from 25 o °C to 85 o °C at a heating rate of 5 o °C per hour. After the reaction is completed, perform vacuum drying (-0.06 MPa) using an oil pump to obtain styrene-modified cinnamic acid.

[0065] Step 5: Prepare a surface treatment agent, specifically as follows: Take 5 g of styrene-modified cashew phenol, 0.2 g of bis-styrene-modified strong acid, 2 g of styrene-modified salicylic acid, 1 g of acrylic acid, and 2 g of N-hydroxyethyl acrylamide and disperse them in 10 mL of toluene solution. Then add 10 mg of azobisisobutyronitrile, raise the temperature to 60 o °C, control the product viscosity at 10000 - 15000 cps, and immediately stop heating. After the temperature drops to room temperature, add 5 mg of p-methoxyphenol to obtain the surface treatment agent.

[0066] Step 6: Prepare a bio-based UV-curable adhesive, specifically as follows: Take 5 g of styrene-modified cashew phenol, 0.2 g of bis-styrene-modified strong acid, 5 g of styrene-modified salicylic acid, 3 g of styrene-modified cinnamic acid, and 5 g of 2-[2-(2-methoxyethoxy)ethoxy]ethyl acrylate and disperse them in 10 mL of toluene solution. Then add 10 mg of azobisisobutyronitrile, raise the temperature to 60 o °C, control the product viscosity at 10000 - 15000 cps, and immediately stop heating. After the temperature drops to room temperature, add 5 mg of p-methoxyphenol to obtain the bio-based UV-curable adhesive.

[0067] Step 7: Prepare a bio-based UV pressure-sensitive adhesive tape, specifically as follows: Select a polyurethane film (25 g / m 2 ²) as the tape substrate. First, coat a layer of surface treatment agent on the upper surface of the substrate, with a coating thickness of 5 μm. Then place the substrate in an oven at 40 o °C for 20 min. For the surface-treated substrate, continue to coat a layer of UV-curable adhesive, with a coating thickness of 30 μm. Then place the obtained tape in an oven at 40 o °C for 40 min to obtain the bio-based UV pressure-sensitive adhesive tape.

[0068] Comparative Example 3 (When synthesizing the bio-based UV-curable adhesive, no bis-styrene-modified strong acid was added, the bio-based UV-curable adhesive did not form a cross-linked structure, and there was residual glue on the tape after peeling.) Step 1, prepare styrene-modified cashew phenol, specifically: Take 3.02 g of cashew phenol (molar amount is 0.01 mol), dissolve it in 30 mL of N,N-dimethylformamide solution, then add 1.38 g of potassium carbonate, and stir at room temperature for 10 min. Then, place the reaction flask in an ice-water bath, and then dropwise add 1.53 g of 4-vinylbenzyl chloride (the dropping time is 20 min). After the dropping is completed, the temperature is raised to room temperature, and the reaction continues for 2 h. After the reaction is completed, directly pour the reaction solution into 200 mL of 0 o C deionized water to obtain a light yellow solid. The solid is washed three times with 200 mL of deionized water, and the solid is dried at 40 o C for 12 h to obtain styrene-modified cashew phenol.

[0069] Step 2, prepare bis-styrene-modified strong acid, specifically: Add 30 mL of N,N-dimethylformamide solution to the reaction flask. Take 3.18 g of strong acid 5-(octadecyl-8-enyl)benzene-1,3-diol (the molar amount of strong acid is 0.01 mol) and dissolve it in the N,N-dimethylformamide solution, then add 2.76 g of potassium carbonate, and stir at room temperature for 10 min. Then, place the reaction flask in an ice-water bath, and then dropwise add 3.06 g of 4-vinylbenzyl chloride (the dropping time is 20 min). After the dropping is completed, the temperature is raised to room temperature, and the reaction continues for 2 h. After the reaction is completed, directly pour the reaction solution into 200 mL, 0 o C deionized water to obtain a light yellow solid. The solid is washed three times with 200 mL of deionized water, and the solid is dried at 40 o C for 12 h to obtain bis-styrene-modified strong acid.

[0070] Step 3, prepare styrene-modified salicylic acid, specifically: Step 3.1, take 1.38 g of salicylic acid (the molar amount of salicylic acid is 0.01 mol), add it to 30 mL of methanol solution, then add 0.2 mL of H2SO4, and stir at room temperature for 8 min. After the reaction is completed, spin-dry the reaction solution, and then purify it by column chromatography separation technology (the stationary phase is silica gel, and the mobile phase is n-hexane and chloroform, where v:v = 10:1) to obtain colorless methyl salicylate; Step 3.2: Take the methyl salicylate prepared in Step 3.1, dissolve it in 30 mL of N,N-dimethylformamide solution in a reaction flask, then add 1.38 g of potassium carbonate, and stir at room temperature for 10 min. Then, place the reaction flask in an ice-water bath, and subsequently add dropwise 1.53 g of 4-vinylbenzyl chloride (the dropping time is 20 min). After the dropping is completed, the temperature is raised to room temperature, and the reaction continues for 2 h. After the reaction is completed, directly pour the reaction solution into 200 mL of deionized water at 0 o °C to obtain a pale yellow solid. The solid is further washed three times with 200 mL of deionized water, and the solid is dried at 40 o °C for 12 h to obtain styrene-modified methyl salicylate; Step 3.3: Dissolve the styrene-modified methyl salicylate obtained in Step 3.2 in 20 mL of N,N-dimethylformamide solution, then add 20 mL of deionized water and 0.4 g of sodium hydroxide, and stir at room temperature for 5 h. Then, add dropwise a 30% HCl solution to adjust the pH of the reaction solution to 7, and continue to stir at room temperature for 1 h. Subsequently, directly pour the obtained reaction solution into 200 mL of deionized water at 0 o °C, and white solid precipitates. Filter directly to obtain styrene-modified salicylic acid.

[0071] Step 4: Prepare styrene-modified cinnamic acid, specifically: Take 1.48 g of cinnamic acid (the molar amount of cinnamic acid is 0.01 mol), dissolve it in 30 mL of toluene solution, then add 0.54 g of sodium methoxide, and stir at room temperature for 30 min. Continue to add 1.53 g of 4-vinylbenzyl chloride and 0.032 g of tetrabutylammonium bromide to the reaction system. The temperature is slowly raised from 25 o °C to 85 o °C at a heating rate of 5 o °C per hour. After the reaction is completed, perform vacuum drying (-0.06 MPa) using an oil pump to obtain styrene-modified cinnamic acid.

[0072] Step 5: Prepare a surface treatment agent, specifically: Take 5 g of styrene-modified cardanol, 0.2 g of bis-styrene-modified strong acid, 2 g of styrene-modified salicylic acid, 1 g of acrylic acid, and 2 g of N-hydroxyethylacrylamide and disperse them in 10 mL of toluene solution. Then add 10 mg of azobisisobutyronitrile, raise the temperature to 60 o °C, control the product viscosity at 10000 - 15000 cps, and immediately stop heating. After the temperature drops to room temperature, add 5 mg of p-methoxyphenol to obtain a surface treatment agent.

[0073] Step 6: Prepare a bio-based UV-curable adhesive, specifically: Disperse 5 g of styrene-modified cashew phenol, 5 g of styrene-modified salicylic acid, 1 g of allyl isocyanate, 3 g of styrene-modified cinnamic acid, and 5 g of 2-[2-(2-methoxyethoxy)ethoxy]ethyl acrylate in 10 mL of toluene solution. Then add 10 mg of azobisisobutyronitrile and raise the temperature to 60 o °C, control the product viscosity at 10,000 - 15,000 cps, and immediately stop heating. After the temperature drops to room temperature, add 5 mg of p-hydroxyanisole to obtain a bio-based UV-curable adhesive.

[0074] Step 7: Prepare a bio-based UV pressure-sensitive adhesive tape, specifically: Select a polyurethane film (25 g / m 2 ²) as the tape substrate. First, coat a surface treatment agent on the upper surface of the substrate with a coating thickness of 5 μm, and then place the substrate in a 40 o °C oven for 20 min. For the surface-treated substrate, continue to coat a layer of UV-curable adhesive with a coating thickness of 30 μm, and then place the obtained tape in a 40 o °C oven for 40 min to obtain the bio-based UV pressure-sensitive adhesive tape.

[0075] Comparative Example 4 (When preparing the bio-based UV-curable adhesive, styrene-modified cinnamic acid was not added, and deep cross-linking could not occur during UV irradiation, so volume shrinkage could not reduce the viscosity) Step 1: Prepare styrene-modified cashew phenol, specifically: Take 3.02 g of cashew phenol (molar amount 0.01 mol), dissolve it in 30 mL of N,N-dimethylformamide solution, then add 1.38 g of potassium carbonate, and stir at room temperature for 10 min. Then, place the reaction flask in an ice-water bath, and subsequently dropwise add 1.53 g of 4-vinylbenzyl chloride (the dropping time is 20 min). After the dropping is completed, raise the temperature to room temperature and continue the reaction for 2 h. After the reaction is completed, directly pour the reaction solution into 200 mL of 0 o °C deionized water to obtain a pale yellow solid. The solid is further washed three times with 200 mL of deionized water, and the solid is dried at 40 o °C for 12 h to obtain styrene-modified cashew phenol.

[0076] Step 2: Prepare bis-styrene-modified strong acid, specifically: Add 30 mL of N,N-dimethylformamide solution to the reaction flask. Take 3.18 g of strong acid 5-(octadecyl-8-enyl)benzene-1,3-diol (the molar amount of the strong acid is 0.01 mol) and dissolve it in the N,N-dimethylformamide solution. Then add 2.76 g of potassium carbonate and stir at room temperature for 10 min. Then, place the reaction flask in an ice-water bath, and then slowly add 3.06 g of 4-vinylbenzyl chloride (the dropping time is 20 min). After the dropping is completed, raise the temperature to room temperature and continue the reaction for 2 h. After the reaction is completed, pour the reaction solution directly into 200 mL of deionized water at 0 o °C to obtain a pale yellow solid. The solid is washed three times with 200 mL of deionized water, and the solid is dried at 40 o °C for 12 h to obtain styrene-modified strong acid.

[0077] Step 3: Prepare styrene-modified salicylic acid, specifically: Step 3.1: Take 1.38 g of salicylic acid (the molar amount of salicylic acid is 0.01 mol), add it to 30 mL of methanol solution, and then add 0.2 mL of H2SO4. Stir at room temperature for 8 min. After the reaction is completed, the reaction solution is rotary evaporated and then purified by column chromatography separation technology (the stationary phase is silica gel, and the mobile phase is n-hexane and chloroform, where v:v = 10:1) to obtain colorless methyl salicylate; Step 3.2: Take the methyl salicylate prepared in Step 3.1 and dissolve it in 30 mL of N,N-dimethylformamide solution in a reaction flask. Then add 1.38 g of potassium carbonate and stir at room temperature for 10 min. Then, place the reaction flask in an ice-water bath, and then slowly add 1.53 g of 4-vinylbenzyl chloride (the dropping time is 20 min). After the dropping is completed, raise the temperature to room temperature and continue the reaction for 2 h. After the reaction is completed, pour the reaction solution directly into 200 mL of deionized water at 0 o °C to obtain a pale yellow solid. The solid is washed three times with 200 mL of deionized water, and the solid is dried at 40 o °C for 12 h to obtain styrene-modified methyl salicylate; Step 3.3: Dissolve the styrene-modified methyl salicylate obtained in Step 3.2 in 20 mL of N,N-dimethylformamide solution, then add 20 mL of deionized water and 0.4 g of sodium hydroxide, and stir at room temperature for 5 h. Then add a 30% HCl solution by dropping to adjust the pH of the reaction solution to 7, and continue to stir at room temperature for 1 h. Subsequently, pour the obtained reaction solution directly into 200 mL of deionized water at 0 o °C, and white solid precipitates. Filter directly to obtain styrene-modified salicylic acid.

[0078] Step 4, Preparation of surface treatment agent, specifically: Take 5 g of styrene-modified cashew phenol, 0.2 g of bis-styrene-modified strong acid, 2 g of styrene-modified salicylic acid, 1 g of acrylic acid, and 2 g of N-hydroxyethyl acrylamide and disperse them in 10 mL of toluene solution. Then add 10 mg of azobisisobutyronitrile, raise the temperature to 60 o °C, control the product viscosity at 10,000 - 15,000 cps, and immediately stop heating. After the temperature drops to room temperature, add 5 mg of p-hydroxyanisole to obtain the surface treatment agent.

[0079] Step 5, Preparation of bio-based UV-curable adhesive, specifically: Take 5 g of styrene-modified cashew phenol, 0.2 g of bis-styrene-modified strong acid, 5 g of styrene-modified salicylic acid, 1 g of allyl isocyanate, and 5 g of 2-[2-(2-methoxyethoxy)ethoxy]ethyl acrylate and disperse them in 10 mL of toluene solution. Then add 10 mg of azobisisobutyronitrile, raise the temperature to 60 o °C, control the product viscosity at 10,000 - 15,000 cps, and immediately stop heating. After the temperature drops to room temperature, add 5 mg of p-hydroxyanisole to obtain the bio-based UV-curable adhesive.

[0080] Step 6, Preparation of bio-based UV pressure-sensitive adhesive tape, specifically: Select a polyurethane film (25 g / m 2 ²) as the tape substrate. First, coat a layer of surface treatment agent on the upper surface of the substrate, with a coating thickness of 5 μm, and then place the substrate in a 40 o °C oven for 20 min. For the surface-treated substrate, continue to coat a layer of UV-curable adhesive, with a coating thickness of 30 μm, and then place the obtained tape in a 40 o °C oven for 40 min to obtain the bio-based UV pressure-sensitive adhesive tape.

[0081] Comparative Example 5 (When preparing the bio-based UV-curable adhesive, styrene-modified salicylic acid is not added, and the initial tack of the tape decreases) Step 1, Preparation of styrene-modified cashew phenol, specifically: Take 3.02 g of cashew phenol (molar amount of 0.01 mol), dissolve it in 30 mL of N,N-dimethylformamide solution, and then add 1.38 g of potassium carbonate, and stir at room temperature for 10 min. Then, place the reaction flask in an ice-water bath, and then dropwise add 1.53 g of 4-vinylbenzyl chloride (the dropping time is 20 min). After the dropping is completed, raise the temperature to room temperature and continue the reaction for 2 h. After the reaction is completed, directly pour the reaction solution into 200 mL of 0 oIn deionized water of C, a pale yellow solid was obtained. The solid was further washed three times with 200 mL of deionized water and dried at 40 o °C for 12 h to obtain styrene-modified cashew phenol.

[0082] Step 2: Prepare bis-styrene-modified strong acid, specifically as follows: Add 30 mL of N,N-dimethylformamide solution to a reaction flask. Take 3.18 g of strong acid 5-(octadecyl-8-enyl)benzene-1,3-diol (the molar amount of the strong acid is 0.01 mol) and dissolve it in the N,N-dimethylformamide solution. Then add 2.76 g of potassium carbonate and stir at room temperature for 10 min. Then, place the reaction flask in an ice-water bath and subsequently dropwise add 3.06 g of 4-vinylbenzyl chloride (the dropping time is 20 min). After the dropping is completed, raise the temperature to room temperature and continue the reaction for 2 h. After the reaction is completed, directly pour the reaction solution into 200 mL of deionized water at 0 o °C to obtain a pale yellow solid. The solid was further washed three times with 200 mL of deionized water and dried at 40 o °C for 12 h to obtain bis-styrene-modified strong acid.

[0083] Step 3: Prepare styrene-modified salicylic acid, specifically as follows: Step 3.1: Take 1.38 g of salicylic acid (the molar amount of salicylic acid is 0.01 mol), add it to 30 mL of methanol solution, and then add 0.2 mL of H2SO4. Stir at room temperature for 8 min. After the reaction is completed, spin-dry the reaction solution and purify it by column chromatography separation technology (the stationary phase is silica gel, and the mobile phase is n-hexane and chloroform, where v:v = 10:1) to obtain colorless methyl salicylate; Step 3.2: Take the methyl salicylate prepared in Step 3.1 and dissolve it in 30 mL of N,N-dimethylformamide solution contained in a reaction flask. Then add 1.38 g of potassium carbonate and stir at room temperature for 10 min. Then, place the reaction flask in an ice-water bath and subsequently dropwise add 1.53 g of 4-vinylbenzyl chloride (the dropping time is 20 min). After the dropping is completed, raise the temperature to room temperature and continue the reaction for 2 h. After the reaction is completed, directly pour the reaction solution into 200 mL of deionized water at 0 o °C to obtain a pale yellow solid. The solid was further washed three times with 200 mL of deionized water and dried at 40 o °C for 12 h to obtain styrene-modified methyl salicylate; Step 3.3, Dissolve the methyl salicylate modified by styrene obtained in Step 3.2 in 20 mL of N,N-dimethylformamide solution, then add 20 mL of deionized water and 0.4 g of sodium hydroxide, and stir at room temperature for 5 h. Then, add a 30% HCl solution dropwise to adjust the pH of the reaction solution to 7, and continue to stir at room temperature for 1 h. Subsequently, directly pour the obtained reaction solution into 200 mL of deionized water at 0 o C, and white solid precipitates. Filter directly to obtain styrene-modified salicylic acid.

[0084] Step 4, Prepare styrene-modified cinnamic acid, specifically: Take 1.48 g of cinnamic acid (the molar amount of cinnamic acid is 0.01 mol), dissolve it in 30 mL of toluene solution, then add 0.54 g of sodium methoxide, and stir at room temperature for 30 min. Continue to add 1.53 g of 4-vinylbenzyl chloride and 0.032 g of tetrabutylammonium bromide to the reaction system, and slowly raise the temperature from 25 o C to 85 o C at a heating rate of 5 o C per hour. After the reaction is completed, perform vacuum drying (-0.06 MPa) using an oil pump to obtain styrene-modified cinnamic acid.

[0085] Step 5, Preparation of the surface treatment agent Take 5 g of styrene-modified cardanol, 0.2 g of bis-styrene-modified strong acid, 2 g of styrene-modified salicylic acid, 1 g of acrylic acid, and 2 g of N-hydroxyethyl acrylamide and disperse them in 10 mL of toluene solution. Then add 10 mg of azobisisobutyronitrile, raise the temperature to 60 o C, control the product viscosity at 10000 - 15000 cps, and immediately stop heating. After the temperature drops to room temperature, add 5 mg of p-methoxyphenol to obtain the surface treatment agent.

[0086] Step 6, Preparation of the bio-based UV-curable adhesive, specifically: Take 5 g of styrene-modified cardanol, 0.2 g of bis-styrene-modified strong acid, 1 g of allyl isocyanate, 3 g of styrene-modified cinnamic acid, and 5 g of 2-[2-(2-methoxyethoxy)ethoxy]ethyl acrylate and disperse them in 10 mL of toluene solution. Then add 10 mg of azobisisobutyronitrile, raise the temperature to 60 o C, control the product viscosity at 10000 - 15000 cps, and immediately stop heating. After the temperature drops to room temperature, add 5 mg of p-methoxyphenol to obtain the bio-based UV-curable adhesive.

[0087] Step 7, Prepare the bio-based UV pressure-sensitive adhesive tape, specifically: Select a polyurethane film (25 g / m 2 ), as the tape substrate. First, coat a surface treatment agent on the upper surface of the substrate, with a coating thickness of 5 μm. Then, place the substrate in a 40 o °C oven for 20 min. For the substrate after surface treatment, continue to coat a layer of UV-curable adhesive, with a coating thickness of 30 μm. Then, place the obtained tape in a 40 o °C oven for 40 min to obtain the bio-based UV pressure-sensitive adhesive tape with reduced adhesion.

[0088] Comparative Example 6 (When preparing the bio-based UV-curable adhesive, replacing styrene-modified salicylic acid with acrylic acid results in a decrease in the initial adhesion of the tape) Step 1: Prepare styrene-modified cardanol, specifically: Take 3.02 g of cardanol (molar amount of 0.01 mol), dissolve it in 30 mL of N,N-dimethylformamide solution, and then add 1.38 g of potassium carbonate. Stir at room temperature for 10 min. Then, place the reaction flask in an ice-water bath, and subsequently add dropwise 1.53 g of 4-vinylbenzyl chloride (the dropping time is 20 min). After the dropping is completed, raise the temperature to room temperature and continue the reaction for 2 h. After the reaction is completed, directly pour the reaction solution into 200 mL of 0 o °C deionized water to obtain a pale yellow solid. The solid is washed three times with 200 mL of deionized water, and the solid is dried at 40 o °C for 12 h to obtain styrene-modified cardanol.

[0089] Step 2: Prepare bis-styrene-modified strong acid, specifically: Add 30 mL of N,N-dimethylformamide solution to the reaction flask. Take 3.18 g of strong acid 5-(octadecyl-8-enyl)benzene-1,3-diol (molar amount of the strong acid is 0.01 mol) and dissolve it in the N,N-dimethylformamide solution, and then add 2.76 g of potassium carbonate. Stir at room temperature for 10 min. Then, place the reaction flask in an ice-water bath, and subsequently add dropwise 3.06 g of 4-vinylbenzyl chloride (the dropping time is 20 min). After the dropping is completed, raise the temperature to room temperature and continue the reaction for 2 h. After the reaction is completed, directly pour the reaction solution into 200 mL of 0 o °C deionized water to obtain a pale yellow solid. The solid is washed three times with 200 mL of deionized water, and the solid is dried at 40 o °C for 12 h to obtain bis-styrene-modified strong acid.

[0090] Step 3: Prepare styrene-modified salicylic acid, specifically: Step 3.1: Take 1.38 g of salicylic acid (the molar amount of salicylic acid is 0.01 mol), add it to 30 mL of methanol solution, then add 0.2 mL of H2SO4, and stir at room temperature for 8 min. After the reaction is completed, the reaction solution is rotary evaporated and then purified by column chromatography separation technology (the stationary phase is silica gel, and the mobile phase is n-hexane and chloroform, where v:v = 10:1) to obtain colorless methyl salicylate; Step 3.2: Take the methyl salicylate prepared in Step 3.1, dissolve it in 30 mL of N,N-dimethylformamide solution in a reaction flask, then add 1.38 g of potassium carbonate, and stir at room temperature for 10 min. Then, place the reaction flask in an ice-water bath, and then add dropwise 1.53 g of 4-vinylbenzyl chloride (the dropping time is 20 min). After the dropping is completed, the temperature is raised to room temperature and the reaction continues for 2 h. After the reaction is completed, pour the reaction solution directly into 200 mL of deionized water at 0 o °C to obtain a light yellow solid. The solid is washed three times with 200 mL of deionized water, and the solid is dried at 40 o °C for 12 h to obtain styrene-modified methyl salicylate; Step 3.3: Dissolve the styrene-modified methyl salicylate obtained in Step 3.2 in 20 mL of N,N-dimethylformamide solution, then add 20 mL of deionized water and 0.4 g of sodium hydroxide, and stir at room temperature for 5 h. Then, add dropwise a 30% HCl solution by mass to adjust the pH of the reaction solution to 7, and continue to stir at room temperature for 1 h. Subsequently, pour the obtained reaction solution directly into 200 mL of deionized water at 0 o °C, and white solid precipitates. Filter directly to obtain styrene-modified salicylic acid.

[0091] Step 4: Prepare styrene-modified cinnamic acid, specifically: Take 1.48 g of cinnamic acid (the molar amount of cinnamic acid is 0.01 mol), dissolve it in 30 mL of toluene solution, then add 0.54 g of sodium methoxide, and stir at room temperature for 30 min. Continue to add 1.53 g of 4-vinylbenzyl chloride and 0.032 g of tetrabutylammonium bromide to the reaction system. The temperature is slowly raised from 25 o °C to 85 o °C at a heating rate of 5 o °C per hour. After the reaction is completed, perform vacuum drying (-0.06 MPa) with an oil pump to obtain styrene-modified cinnamic acid.

[0092] Step 5, Preparation of the surface treatment agent: Specifically, take 5 g of styrene-modified cardanol, 0.2 g of bis-styrene-modified strong acid, 2 g of styrene-modified salicylic acid, 1 g of acrylic acid, and 2 g of N-hydroxyethyl acrylamide and disperse them in 10 mL of toluene solution. Then add 10 mg of azobisisobutyronitrile, raise the temperature to 60 o °C, control the product viscosity at 10,000 - 15,000 cps, and immediately stop heating. After the temperature drops to room temperature, add 5 mg of p-hydroxyanisole to obtain the surface treatment agent.

[0093] Step 6, Preparation of the bio-based UV-curable adhesive: Specifically, Take 5 g of styrene-modified cardanol, 0.2 g of bis-styrene-modified strong acid, 5 g of acrylic acid, 1 g of allyl isocyanate, 3 g of styrene-modified cinnamic acid, and 5 g of 2-[2-(2-methoxyethoxy)ethoxy]ethyl acrylate and disperse them in 10 mL of toluene solution. Then add 10 mg of azobisisobutyronitrile, raise the temperature to 60 o °C, control the product viscosity at 10,000 - 15,000 cps, and immediately stop heating. After the temperature drops to room temperature, add 5 mg of p-hydroxyanisole to obtain the bio-based UV-curable adhesive.

[0094] Step 7, Preparation of the bio-based UV pressure-sensitive adhesive tape: Specifically, Select a polyurethane film (25 g / m 2 ²) as the tape substrate. First, coat a layer of the surface treatment agent on the upper surface of the substrate, with a coating thickness of 5 μm, and then place the substrate in a 40 o °C oven for 20 min. For the substrate after surface treatment, continue to coat a layer of the UV-curable adhesive, with a coating thickness of 30 μm, and then place the obtained tape in a 40 o °C oven for 40 min to obtain the bio-based UV pressure-sensitive adhesive tape.

[0095] Comparative Example 7 (When preparing the bio-based UV-curable adhesive, replacing styrene-modified cardanol with styrene results in a decrease in the initial tack of the tape) Step 1, Preparation of styrene-modified cardanol: Specifically, Take 3.02 g of cardanol (molar amount of 0.01 mol), dissolve it in 30 mL of N,N-dimethylformamide solution, and then add 1.38 g of potassium carbonate and stir at room temperature for 10 min. Then, place the reaction flask in an ice-water bath, and subsequently dropwise add 1.53 g of 4-vinylbenzyl chloride (the dropping time is 20 min). After the dropping is completed, raise the temperature to room temperature and continue the reaction for 2 h. After the reaction is completed, directly pour the reaction solution into 200 mL of 0 oIn deionized water of C, a pale yellow solid was obtained. The solid was further washed three times with 200 mL of deionized water and dried at 40 o °C for 12 h to obtain styrene-modified cardanol.

[0096] Step 2: Preparation of bis-styrene-modified strong acid, specifically: Add 30 mL of N,N-dimethylformamide solution to the reaction flask. Take 3.18 g of strong acid 5-(octadecyl-8-enyl)benzene-1,3-diol (the molar amount of the strong acid is 0.01 mol) and dissolve it in the N,N-dimethylformamide solution. Then add 2.76 g of potassium carbonate and stir at room temperature for 10 min. Then, place the reaction flask in an ice-water bath and subsequently dropwise add 3.06 g of 4-vinylbenzyl chloride (the dropping time is 20 min). After the dropping is completed, raise the temperature to room temperature and continue the reaction for 2 h. After the reaction is completed, pour the reaction solution directly into 200 mL of deionized water at 0 o °C to obtain a pale yellow solid. The solid was further washed three times with 200 mL of deionized water and dried at 40 o °C for 12 h to obtain bis-styrene-modified strong acid. Step 3: Preparation of styrene-modified salicylic acid, specifically: Step 3.1: Take 1.38 g of salicylic acid (the molar amount of salicylic acid is 0.01 mol), add it to 30 mL of methanol solution, and then add 0.2 mL of H2SO4. Stir at room temperature for 8 min. After the reaction is completed, spin-dry the reaction solution and purify it using column chromatography separation technology (the stationary phase is silica gel, and the mobile phase is n-hexane and chloroform, where v:v = 10:1) to obtain colorless methyl salicylate; Step 3.2: Take the methyl salicylate prepared in Step 3.1 and dissolve it in 30 mL of N,N-dimethylformamide solution in the reaction flask. Then add 1.38 g of potassium carbonate and stir at room temperature for 10 min. Then, place the reaction flask in an ice-water bath and subsequently dropwise add 1.53 g of 4-vinylbenzyl chloride (the dropping time is 20 min). After the dropping is completed, raise the temperature to room temperature and continue the reaction for 2 h. After the reaction is completed, pour the reaction solution directly into 200 mL of deionized water at 0 o °C to obtain a pale yellow solid. The solid was further washed three times with 200 mL of deionized water and dried at 40 o °C for 12 h to obtain styrene-modified methyl salicylate; Step 3.3: Dissolve the methyl salicylate modified by styrene obtained in Step 3.2 in 20 mL of N,N-dimethylformamide solution, then add 20 mL of deionized water and 0.4 g of sodium hydroxide, and stir at room temperature for 5 h. Then, dropwise add 30% HCl solution to adjust the pH of the reaction solution to 7, and continue to stir at room temperature for 1 h. Subsequently, directly pour the obtained reaction solution into 200 mL of deionized water at 0 o °C, and white solid precipitates. Filter directly to obtain styrene-modified salicylic acid.

[0097] Step 4: Prepare styrene-modified cinnamic acid, specifically: Take 1.48 g of cinnamic acid (the molar amount of cinnamic acid is 0.01 mol), dissolve it in 30 mL of toluene solution, then add 0.54 g of sodium methoxide, and stir at room temperature for 30 min. Continue to add 1.53 g of 4-vinylbenzyl chloride and 0.032 g of tetrabutylammonium bromide to the reaction system, and slowly raise the temperature from 25 o °C to 85 o °C at a heating rate of 5 o °C per hour. After the reaction is completed, perform vacuum drying (-0.06 MPa) using an oil pump to obtain styrene-modified cinnamic acid.

[0098] Step 5: Prepare a surface treatment agent, specifically: Take 5 g of styrene-modified cardanol, 0.2 g of bis-styrene-modified strong acid, 2 g of styrene-modified salicylic acid, 1 g of acrylic acid, and 2 g of N-hydroxyethyl acrylamide and disperse them in 10 mL of toluene solution. Then add 10 mg of azobisisobutyronitrile, raise the temperature to 60 o °C, control the product viscosity at 10000 - 15000 cps, and immediately stop heating. After the temperature drops to room temperature, add 5 mg of p-methoxyphenol to obtain the surface treatment agent.

[0099] Step 6: Prepare a bio-based UV-curable adhesive, specifically: Take 5 g of styrene, 0.2 g of bis-styrene-modified strong acid, 5 g of styrene-modified salicylic acid, 1 g of allyl isocyanate, 3 g of styrene-modified cinnamic acid, and 5 g of 2-[2-(2-methoxyethoxy)ethoxy]ethyl acrylate and disperse them in 10 mL of toluene solution. Then add 10 mg of azobisisobutyronitrile, raise the temperature to 60 o °C, control the product viscosity at 10000 - 15000 cps, and immediately stop heating. After the temperature drops to room temperature, add 5 mg of p-methoxyphenol to obtain the bio-based UV-curable adhesive.

[0100] Step 7: Prepare a bio-based UV pressure-sensitive adhesive tape, specifically: Select a polyurethane film (25 g / m2 is the tape substrate. First, a surface treatment agent is coated on the upper surface of the substrate with a coating thickness of 5 μm, and then the substrate is placed in an oven at 40 o °C for 20 min. For the surface-treated substrate, a UV-curable adhesive is continuously coated with a coating thickness of 30 μm, and then the obtained tape is placed in an oven at 40 o °C for 40 min to obtain the bio-based UV-reduced tack tape.

[0101] The performances of the tapes prepared in Examples 1 to 3 and Comparative Examples 1 to 7 were tested, and the results are shown in Table 1 below: Table 1

[0102] Whether there is glue residue when the tape is peeled off. The method is to stick the tape on the surface of the wafer and press it with a force of 10 N to make it fit tightly on the surface of the wafer, and then irradiate it with a 45 W ultraviolet lamp for 30 s. After peeling, observe whether there is glue residue on the surface of the wafer. For the tests of the initial tack and the tack after UV curing, after the tape and the surface of the wafer are closely adhered, the force required for peeling is measured respectively before and 180 o seconds after UV curing; at the same time, the volume shrinkage rate is the change rate of the thickness of the adhesive layer before and after UV curing (since the bottom area remains unchanged, its value is equal to the volume shrinkage rate) , where L0 is the thickness of the adhesive layer before UV irradiation and L1 is the thickness of the adhesive layer after UV irradiation.

[0103] In Examples 1 to 3, the adhesive layer contains an allyl isocyanate structural unit, and the surface treatment layer contains an N-hydroxyethyl acrylamide unit. The chemical reaction activity between isocyanate and hydroxyl group is high and they are easy to react, making the adhesive layer and the surface treatment layer firmly bonded, and no adhesive falls off from the surface treatment layer, and there is no glue residue. Due to the presence of a styrene-modified cinnamic acid unit in the adhesive layer, after UV curing, the volume shrinkage is obvious, and the tack of the tape can be reduced, as Figure 2 shown.

[0104] In Comparative Example 1, N-hydroxyethyl acrylamide is not added to the surface treatment agent, and the isocyanate functional group of the adhesive layer cannot react with the surface treatment layer. When the tape is peeled off, the adhesive layer is easily peeled off from the surface treatment layer, and there is glue residue when the tape is peeled off.

[0105] In Comparative Example 2, allyl isocyanate is not added to the bio-based UV-curable adhesive, and the adhesive layer and the surface treatment layer cannot react. When the adhesive layer is peeled off, it is easily peeled off from the surface treatment layer, and there is glue residue when the tape is peeled off.

[0106] In Comparative Example 3, no bisstyrene-modified strong acid was added during the preparation of the bio-based UV curable agent. Although styrene-modified cinnamic acid units in the tape can also cyclize and crosslink during tape UV curing, the main skeleton of the adhesive is not crosslinked, and the UV curing of styrene-modified cinnamic acid units is a reversible reaction, with limited reaction of cinnamic acid functional groups and adhesive residue remaining.

[0107] In Comparative Example 4, no styrene-modified cinnamic acid was added during the preparation of the bio-based UV curable adhesive. It could not crosslink and thus could not shrink in volume upon UV irradiation, resulting in poor UV debonding effect. Since the main skeleton of the adhesive layer contains a crosslinked structure of bisstyrene-modified strong acid, there is no adhesive residue.

[0108] In Comparative Example 5, no styrene-modified salicylic acid was added during the preparation of the bio-based UV curable adhesive, and the initial tack of the resulting tape decreased.

[0109] In Comparative Example 6, when styrene-modified salicylic acid was replaced with acrylic acid during the preparation of the bio-based UV curable adhesive, the initial tack of the tape increased. This is because under the same mass condition, the higher molar quantity of acrylic acid can form more hydrogen bonds; however, the acidity increased, and when the concentration was 0.2 g / mL, the pH decreased from 6 to about 5, and the increased acidity would enhance its corrosiveness.

[0110] In Comparative Example 7, when styrene-modified cardanol was replaced with styrene during the preparation of the bio-based UV curable tape, the initial tack of the tape decreased. Styrene-modified cardanol contains a long side chain, which is beneficial to the improvement of tack. From the perspective of the soft and hard monomers of the adhesive, styrene contains a rigid aromatic ring and is a hard monomer; while cardanol contains not only a rigid aromatic ring but also a long flexible side chain, taking into account both the soft and hard characteristics of the monomers. At the same time, the side chain is short, and after the tape is UV cured, it is not conducive to volume shrinkage, and the peel force does not decrease significantly.

[0111] Example 4 Compared with Example 1, in Step 1, the volume of the N,N-dimethylformamide solution was 35 mL, and the remaining steps were the same as those in Example 1.

[0112] Example 5 Compared with Example 1, in Step 2, the volume of the N,N-dimethylformamide solution was 55 mL, and the remaining steps were the same as those in Example 1.

[0113] Example 6 Compared with Example 1, in Step 4, the volume of the toluene solution was 55 mL.

[0114] The characteristics of the manufacturing method of the bio-based UV tack-reducing tape of the present invention are as follows: Styrene-modified cardanol and styrene-modified salicylic acid are introduced into the adhesive. Thanks to the long side chain in the cardanol moiety and the presence of the carboxyl group in the salicylic acid moiety, the initial tack of the tape can be greatly improved. At the same time, by using styrene-modified salicylic acid to replace the conventional acrylic monomer, the acidity of the tape can be reduced, thereby reducing the corrosiveness. In principle, UV-induced volume shrinkage is used to reduce tack, while the principle of UV-induced adhesive decomposition to reduce tack is abandoned. The adhesive contains 6 monomers, among which four monomers are synthesized from biomass as raw materials, greatly reducing the use of petroleum-based monomers and conforming to the concept of green environmental protection.

Claims

1. Method for manufacturing bio-based UV tack-reducing tape, characterized in that: Specifically, it includes the following steps: Step 1, prepare styrene-modified cashew phenol; Step 2, prepare bis-styrene-modified strong acid; Step 3, prepare styrene-modified salicylic acid; Step 4, prepare styrene-modified cinnamic acid; Step 5, prepare a surface treatment agent according to the products obtained in Steps 1 to 3; Step 6, prepare a bio-based UV-curable adhesive according to the products obtained in Steps 1 to 4; Step 7, take a polyurethane film as the tape substrate. First, coat a layer of surface treatment agent on the upper surface of the tape substrate for surface treatment. Subsequently, on the tape substrate that has undergone surface treatment, continue to coat a layer of UV-curable adhesive, and obtain a bio-based UV-reducing adhesive tape after drying treatment.

2. The manufacturing method of the bio-based UV tack-reducing tape according to claim 1, characterized in that: The specific process of the said step 1 is as follows: Dissolve cardanol in N,N-dimethylformamide solution, then add a certain amount of potassium carbonate, stir at room temperature for 10 - 20 min, then place the reaction flask in an ice-water bath, and subsequently dropwise add 4-vinylbenzyl chloride. After the addition is completed, raise the temperature to room temperature and continue the reaction for 2 - 4 h. After the reaction is completed, directly pour the reaction solution into deionized water to obtain a pale yellow solid. Wash the pale yellow solid three times with deionized water, and dry the solid at 40 - 50 o °C for 12 - 24 h to obtain styrene-modified cardanol; wherein, the molar ratio of cardanol: potassium carbonate: 4-vinylbenzyl chloride is 1:1:

1.

3. The manufacturing method of the bio-based UV tack-reducing tape according to claim 2, wherein: The specific process of step 2 is as follows: Add N,N-dimethylformamide solution to the reaction flask, dissolve strong acid in the N,N-dimethylformamide solution, add potassium carbonate, and stir at room temperature for 10 - 20 min; then, place the reaction flask in an ice-water bath, and then dropwise add 4-vinylbenzyl chloride. After the addition is completed, raise the temperature to room temperature and continue the reaction for 2 - 4 h. After the reaction is completed, directly pour the reaction solution into deionized water to obtain a pale yellow solid. The solid is washed three times with deionized water and dried at 40 - 50 o °C for 12 - 24 h to obtain strongly acidic resin modified with styrene; wherein, the molar ratio of strong acid: potassium carbonate: 4-vinylbenzyl chloride is 1:2:

2.

4. The manufacturing method of the bio-based UV tack-reducing tape according to claim 3, characterized in that: In Step 2, the strong acid is 5-(octadecyl-8-enyl)benzene-1,3-diol.

5. The manufacturing method of the bio-based UV viscosity-reducing tape according to claim 4, characterized in that: The specific process of Step 3 is as follows: Step 3.1, add salicylic acid to a methanol solution, then add H2SO4, stir at room temperature for 8 - 12 min. After the reaction ends, spin-dry the reaction solution and purify it using column chromatography separation technology to obtain colorless methyl salicylate; Step 3.2: Add N,N-dimethylformamide solution into the reaction flask, dissolve the methyl salicylate prepared in Step 3.1 in the N,N-dimethylformamide solution, add potassium carbonate, and stir at room temperature for 10 - 20 min; then, place the reaction flask in an ice-water bath, and then dropwise add 4-vinylbenzyl chloride. After the addition is complete, raise the temperature to room temperature and continue the reaction for 2 - 4 h; after the reaction is completed, directly pour the reaction solution into deionized water to obtain a pale yellow solid. The solid is washed three times with deionized water and dried at 40 - 50 o °C for 12 - 24 h to obtain styrene-modified methyl salicylate; Step 3.3, dissolve the styrene-modified methyl salicylate obtained in Step 3.2 in an N,N-dimethylformamide solution, add deionized water and sodium hydroxide, stir at room temperature for 5 - 10 h, then dropwise add an HCl solution to adjust the pH of the reaction solution to neutral, and continue to stir at room temperature for 1 - 2 h; Subsequently, directly pour the obtained reaction solution into deionized water, and white solids will precipitate. Filter to obtain styrene-modified salicylic acid.

6. The manufacturing method of the bio-based UV viscosity-reducing tape according to claim 5, characterized in that: The specific process of the said step 4 is as follows: Take cinnamic acid and dissolve it in toluene solution, then add sodium methoxide and stir at room temperature for 30 - 60 min; continue to add 4-vinylbenzyl chloride and tetrabutylammonium bromide to the reaction system, and the heating rate is 5 - 10 o °C per hour; after the reaction is completed, carry out vacuum drying using an oil pump to obtain styrene-modified cinnamic acid, wherein the molar ratio of cinnamic acid:sodium methoxide:4-vinylbenzyl chloride:tetrabutylammonium bromide is 1:1:1:0.

01.

7. The manufacturing method of the bio-based UV tack-reducing tape according to claim 6, characterized in that: The specific process of the said step 5 is as follows: successively take styrene-modified cardanol, bis-styrene-modified strong acid, styrene-modified salicylic acid, acrylic acid and N-hydroxyethyl acrylamide and disperse them in toluene solution, then add azobisisobutyronitrile, raise the temperature to 60-70 o °C, control the product viscosity at 10000-15000 cps, and immediately stop heating; after the temperature drops to room temperature, add p-methoxyphenol to obtain the surface treatment agent.

8. The manufacturing method of the bio-based UV tack-reducing tape according to claim 7, characterized in that: The specific process of the said step 6 is as follows: successively take styrene-modified cardanol, bis-styrene-modified strong acid, styrene-modified salicylic acid, allyl isocyanate, styrene-modified cinnamic acid and 2-[2-(2-methoxyethoxy)ethoxy]ethyl acrylate and disperse them in toluene solution; then add azobisisobutyronitrile, raise the temperature to 60-70 o °C, control the product viscosity at 10,000-15,000 cps, and immediately stop heating; after the temperature drops to room temperature, add p-hydroxyanisole to obtain a bio-based UV-curable adhesive.

9. The manufacturing method of the bio-based UV viscosity-reducing tape according to claim 8, characterized in that: In step 7, the coating thickness of the surface treatment agent is 5 - 10 um, and the surface treatment process is as follows: place the tape substrate in a 40 - 50 o C oven for 20 - 40 min; The coating thickness of the UV-cured adhesive is 30 - 50 um, and the drying process is as follows: Place the tape substrate after surface treatment in an oven at 40 - 50 o °C for 40 - 80 minutes to obtain the bio-based UV release tape.

10. A bio-based UV-reducing adhesive tape is prepared by using the method for preparing a bio-based UV-reducing adhesive tape according to any one of claims 1 to 9.

Images