Environment-friendly adhesive tape for folding screen and preparation process thereof

Abstract

The present application relates to the field of high polymer materials, in particular to an environment-friendly adhesive tape for folding screen and a preparation process thereof. According to the requirements of low-temperature bending resistance, high-temperature viscosity and cohesion of flexible foldable mobile phones, a bio-based acrylate block copolymer with extremely low glass transition temperature and high glass transition temperature is designed, and through the regulation of soft and hard segment ratio, molecular weight and curing agent, the adhesive layer meets certain modulus and adhesion requirements, meets the requirements of low-temperature flexibility, high-temperature cohesion, high-temperature peeling without residual glue, and cutting without glue overflow of the bio-based acrylate copolymer adhesive layer, and solves the problems of macroscopic phase separation due to compatibility problems in conventional blending method, resulting in poor appearance and insufficient adhesion, low-temperature flexibility and poor reliability, and the bio-based ultra-thin double-sided adhesive tape uses bio-based raw materials which are easy to biodegrade in the adhesive layer, and improves the problems of difficult degradation, high pollution and high toxicity of petroleum-based adhesive layers.

Description

An environmentally friendly tape for foldable screens and its preparation process Technical Field

[0001] This invention relates to the field of polymer materials, specifically to an environmentally friendly adhesive tape for foldable screens and its preparation process. Background Technology

[0002] With the continuous development of full-screen technology, the screen-to-body ratio of most mobile phones has exceeded 90%, making it difficult to increase the screen size without increasing the phone's overall size. Larger screen sizes lead to inconvenience in operation and difficulty in carrying around. Flexible foldable phones, first unveiled at the 2019 Mobile World Congress, have become a market hotspot since their introduction due to their combination of portability and versatility, integrating the advantages of mobile phones and tablets, with attention and demand increasing year by year. To cater to current consumer needs, significant resources have been allocated in recent years to promote the development of foldable screen technology.

[0003] Flexible foldable phones place new demands on screen flexibility, necessitating upgrades to screen bonding and under-display bonding to maintain reliable adhesion, appearance, and conductivity even after enduring hundreds of thousands of repeated folding stresses and aging in high and low temperature environments. Existing foldable screen tapes use TPU core materials with high low-temperature tensile strength and elastic modulus, resulting in relatively poor bending resistance and difficulty meeting the connection requirements of internal components in foldable screens. Foam core materials are prone to creases after low-temperature bending, affecting the appearance of the foldable screen. The adhesive layer has extremely low elastic modulus, easily leaving residue at high temperatures and prone to overflow during slitting; the tape is generally thick, requiring multiple coating layers, affecting appearance and increasing costs. Conventional methods of blending other high-Tg resins, if compatibility is good, cannot achieve a double glass transition temperature design, leading to increased elastic modulus and poor low-temperature flexibility, hindering good bendability. If compatibility is poor, macroscopic phase separation occurs, resulting in whitening and pores, and due to macroscopic phase separation, instability in appearance and adhesion, and poor reliability. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a manufacturing process for an environmentally friendly adhesive tape for foldable screens, comprising the following steps:

[0005] Step 1:

[0006] S1: Weigh the polymer monomers for the soft segment of the bio-based acrylate block copolymer, emulsifier KH-10, deionized water, and RAFT reagent, and homogenize them for 10 min at 14000 rpm using a high-speed homogenizer to prepare a nano pre-emulsion with uniform particle size distribution.

[0007] S2: Add the pre-emulsion prepared in S1 into the reactor, and under nitrogen protection, add the initiator and react at 80°C for 5 hours to obtain emulsion A;

[0008] S3: Add bio-based acrylate block copolymer hard segment polymerizing monomer to emulsion A, and continue the polymerization reaction at 75°C for 6 hours under nitrogen protection;

[0009] S4: After polymerization, the reaction system is cooled to 40-60°C, hydrogen peroxide aqueous solution and sodium metabisulfite aqueous solution are added and the reaction continues for 3 hours. Then the temperature is cooled to 30°C and the product is filtered to obtain emulsion B.

[0010] S5: Spray dry emulsion B in a spray drying tower with pressure nozzles. The inlet temperature of the spray drying tower is 135°C and the exhaust temperature is 85°C to obtain bio-based acrylate block copolymer dry powder.

[0011] S6: Dissolve the obtained dry powder in organic solutions such as toluene, ethyl acetate, and butanone to obtain a bio-based acrylate block copolymer solution;

[0012] Step 2: Preparation of bio-based acrylate adhesive solution:

[0013] Add the bio-based acrylate block copolymer solution to the curing agent and stir for 30 minutes to mix well. Let the prepared adhesive solution stand to defoam and set aside.

[0014] Step 3: Preparation of environmentally friendly tape for foldable screens:

[0015] A comma-shaped doctor blade coater is used to apply a bio-based acrylic adhesive liquid to the release surface of the first release layer. The coating is placed in a 100°C oven for 2 minutes to allow the solvent to evaporate and form a bio-based adhesive layer. The thickness of the adhesive layer is controlled to be 25±2μm. The dried adhesive layer is then laminated with the release surface of the second release layer. The coated environmentally friendly tape for folding screens is then cured at room temperature (25°C) for 7 days or at 40°C for 3 days to obtain the environmentally friendly tape for folding screens.

[0016] Furthermore, the rheological curve of the adhesive layer contains at least two glass transition temperatures: a first glass transition temperature Tg1 in the range of -70 to -30°C, and a second glass transition temperature Tg2 in the range of 0 to 65°C.

[0017] Furthermore, the glass transition temperature Tg1 of the acrylate copolymer soft segment is between -80 and -40°C, and the glass transition temperature of the acrylate copolymer hard segment is between -10 and 60°C.

[0018] Furthermore, the acrylate copolymer soft segment is polymerized from soft segment functional monomers and soft segment auxiliary monomers. The soft segment functional monomers are one or more selected from the following: n-butyl acrylate, 2-ethylhexyl acrylate, 2-octyl acrylate, n-octyl acrylate, isooctyl acrylate, isononyl acrylate, isodecyl acrylate, 2-propylheptyl acrylate, tetrahydrofuran acrylate, methoxyethyl acrylate, caprolactone acrylate, ethoxyethoxyethyl acrylate, methoxy polyethylene glycol acrylate, tridecyl acrylate, hexadecyl acrylate, heptadecanyl acrylate, isooctyl methacrylate, lauryl methacrylate, and dodecyl methacrylate. The soft segment auxiliary monomers are one or more selected from the following: methyl acrylate, acrylic acid, acrylamide, 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, methacrylic acid, and methacrylamide.

[0019] Furthermore, the acrylate copolymer hard segment is polymerized from hard segment functional monomers and hard segment auxiliary monomers; the hard segment functional monomers are one or more selected from methyl acrylate, ethyl acrylate, propyl acrylate, isobutyl acrylate, tert-butyl acrylate, n-butyl acrylate, trimethylolpropane formal acrylate, isobornyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, isobornyl methacrylate, cyclohexyl methacrylate, and tetrahydrofuran methacrylate; the hard segment auxiliary monomers are one or more selected from acrylic acid, acrylamide, acrylonitrile, 2-hydroxyethyl acrylate, methacrylic acid, 2-hydroxyethyl methacrylate, and methacrylamide.

[0020] Furthermore, the mass ratio of hard segments to soft segments in the bio-based acrylate block copolymer is 5 / 95 to 50 / 50.

[0021] Furthermore, the weight-average molecular weight (Mw) of the bio-based acrylate block copolymer is between 450,000 and 1,800,000; and the number-average molecular weight is between 130,000 and 200,000.

[0022] Furthermore, the acid value of the bio-based acrylate block copolymer is ≤15mgKOH / g.

[0023] Furthermore, the adhesive layer has a storage modulus G′ of 8–25 kPa at 65°C.

[0024] Furthermore, the adhesive layer has a tanθ (the ratio of loss modulus G″ to storage modulus G′) of 0.4 to 0.8 at 65°C.

[0025] Furthermore, the peel force between any side of the adhesive layer and the mirror steel plate at 65°C is 5.0–8.0 N / inch.

[0026] Compared with existing technologies, the beneficial effects achieved by this invention are as follows: Based on existing technical solutions and combined with the development trend of flexible AMOLED foldable screens, this invention proposes a foldable tape with low low-temperature flexible elastic modulus, good bending resistance, but not prone to residue at high temperatures, and no adhesive overflow during slitting. It is suitable for bonding mobile phone screens to conductive graphite or metal sheets. During the preparation process, the control of the ratio of soft and hard segments, molecular weight, and curing agent can ensure that the adhesive layer meets certain modulus and adhesion requirements.

[0027] Controlling the glass transition temperature (Tg) of the acrylate copolymer soft segment between -80°C and -40°C provides excellent low-temperature flexibility for the adhesive layer. If the Tg of the acrylate copolymer soft segment is less than -80°C, it will be too soft, resulting in insufficient adhesion, easy residue at high temperatures, and affecting the cohesiveness of the adhesive layer, which can easily lead to glue overflow during slitting. If the Tg of the acrylate copolymer soft segment is greater than -40°C, it will be too hard, resulting in insufficient low-temperature flexibility and poor low-temperature bending, thus failing to meet the requirements of low-temperature rheological properties.

[0028] Controlling the glass transition temperature (Tg) of the acrylate copolymer hard segment within the range of -10 to 60°C provides excellent adhesive strength, high peel strength, and high cohesive strength at high temperatures, ensuring product performance at high temperatures and resolving adhesive overflow issues during slitting. If the Tg of the acrylate copolymer hard segment is less than -10°C, it will be too soft, resulting in insufficient adhesion, intermolecular cohesion, easy residue at high temperatures, and poor high-temperature holding power. Conversely, if the Tg of the hard segment of the bio-based acrylate block copolymer is greater than 60°C, it will be too hard and lack sufficient low-temperature flexibility, leading to poor low-temperature bending and failing to meet the requirements for low-temperature rheological properties.

[0029] The weight-average molecular weight (Mw) of the bio-based acrylate block copolymer should be controlled between 450,000 and 1,800,000, and the number-average molecular weight (Mn) between 130,000 and 200,000. If the weight-average molecular weight (Mw) of the bio-based acrylate copolymer is less than 450,000, the cohesion is too low, which affects high-temperature cohesion and causes residual glue overflow problems. If the weight-average molecular weight (Mw) of the bio-based acrylate copolymer is greater than 1,800,000, it is too high and affects low-temperature flexibility.

[0030] In high-temperature applications, polymers need to possess certain functional groups to achieve reasonable crosslinking and cohesion. However, considering that the adhesive layer will be bonded to copper foil in actual use, to avoid discoloration of the copper foil due to excessively high acid values, the acid value is controlled to ≤15.0 mgKOH / g. If the acid value >15.0 mgKOH / g, the bonded copper foil will show significant discoloration. Furthermore, the storage modulus G′ of the adhesive layer at 65℃ is between 8 and 25 kPa. If the storage modulus G′ <8 kPa at 65℃, the high-temperature cohesion is too low, leading to reduced high-temperature residual adhesive peel strength and easy adhesive overflow during slitting. If the storage modulus G′ >25 kPa at 65℃, the adhesive layer is too hard, resulting in insufficient flexibility.

[0031] The tape prepared by this invention meets the requirements of low-temperature flexibility, high-temperature cohesion, high-temperature peeling without residue, and no glue overflow when slitting for the bio-based acrylate copolymer adhesive layer. It also solves the problems of macroscopic phase separation, poor appearance, insufficient stickiness, and low-temperature flexibility caused by compatibility issues in conventional blending methods. Furthermore, the adhesive layer uses easily biodegradable bio-based raw materials, avoiding the problems of difficult degradation, high pollution, and high toxicity of petroleum-based adhesive layers. Attached Figure Description

[0032] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0033] Figure 1 is a schematic diagram of the structure of environmentally friendly tape.

[0034] Figure 2 shows the modulus test results of the adhesive layer in Example 2.

[0035] 1 is the first release layer, 2 is the adhesive layer, and 3 is the second release layer. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] The preparation methods of the adhesive layer solution in Example 1 and Comparative Examples 1-8 are as follows:

[0038] S1: Take the functional monomers and auxiliary monomers of the acrylate copolymer soft segment, emulsifier KH-10 (Daiichi Pharmaceutical Co., Ltd. of Japan), deionized water and RAFT reagent (Maclean), mix them evenly to prepare a nano pre-emulsion; add the initiator under nitrogen protection and react at 80°C for 5 hours to obtain emulsion A;

[0039] Specifically, the acrylate copolymer soft segment is selected from any one or more of 2-ethylhexyl acrylate (2-EHA), 2-propylheptyl acrylate (2-PHA), heptadecanyl acrylate (C17A), n-octyl acrylate (OA), methyl acrylate (MA), and acrylic acid (AA); the RAFT reagent is 4-cyano-4-[[(dodecylthio)thiocarbonyl]thio]valeric acid (R1), and the initiator is ammonium persulfate (APS); the specific formulations (feed ratios) of emulsions A1 to A5 are shown in Table 1.

[0040] Table 1

[0041] Formula EHAOA2-PHAC17AMAAAKH-10R1 Water APSTg (°C) A1 50 20 20 9.2 / 0.8 0.8 1.2 1 20 0.04 -73 A2 / / 99.8 / / 0.2 1.2 1.2 1 20 0.06 -82 A3 40 54.8 / 5 / 0.2 1.2 1.2 1 20 0.05 -50 A4 15 1 220 / 50 0.8 1.2 1.2 1 20 0.06 -38 A5 35 1 220 / 30 3.0 1.2 1.2 1 20 0.06 -50 surface

[0042] S2: Add acrylate copolymer hard segments to emulsion A, and polymerize at 75°C under nitrogen protection for 6 hours. After the reaction is complete, cool down to 50°C, add hydrogen peroxide aqueous solution and sodium metabisulfite aqueous solution and continue the reaction for 3 hours. Then cool down to 30°C, filter, and discharge to obtain emulsion B. Specifically, the acrylate copolymer hard segments can be any one or more of isobutyl acrylate (i-BA), methyl acrylate (MA), acrylonitrile (AN), methyl methacrylate (MMA), isobornyl methacrylate (IBOMA), acrylic acid (AA), and acrylamide (AM). For the specific emulsion B formula (feed ratio), please refer to Table 2.

[0043] Table 2

[0044]

[0045]

[0046] S3: Stir the bio-based acrylate copolymer solution and curing agent evenly, let stand to defoam, and obtain the adhesive layer solution; the specific formula of the adhesive layer solution is shown in Table 3; in Table 3, curing agent C1 is isocyanate BHS8515 (Toyo Ink, solid content: 5%); curing agent C2 is aluminum acetylacetonate (Yangzhou Xingye, solid content: 100%).

[0047] Table 3

[0048]

[0049] The adhesive layer prepared in Examples 1-2 and Comparative Examples 1-8 was coated onto the surface of the first release layer (Yaoyang New Materials, thickness: 50μm, release force of 15-20g / inch), and the other side was coated with the second release layer (Jiangyin Huamei Technology, thickness: 20μm, release force of 3-6g / inch). After curing, an environmentally friendly tape for foldable screens was obtained.

[0050] experiment:

[0051] Unless otherwise specified, all tests below are conducted at 23℃-50%RH.

[0052] 1. Molecular weight test of copolymers:

[0053] The weight-average molecular weight (Mw) of the acrylate copolymers was determined using a Waters E2695 gel permeation chromatography (GPC) system. Test conditions: mobile phase: tetrahydrofuran; column temperature: 40℃; mobile phase flow rate: 1.0 mL / min.

[0054] 2. Modulus test of adhesive layer:

[0055] Using a comma roller scraper, a bio-based acrylic adhesive liquid coating was applied to a 50 μm release layer. The coating was then dried in a 100°C oven for 5 min to obtain a dry film of the adhesive layer. Rheological tests were performed using a TA HR-10 rotational rheometer. The loss modulus (G″) and storage modulus (G′) of the adhesive layer were measured by temperature scanning at a temperature of -100 to 150°C, a heating rate of 5°C / min, a strain of 0.1%, and a frequency of 1 Hz.

[0056] 3. Glass transition temperatures (Tg1, Tg2) of the adhesive layer:

[0057] Using a comma roller scraper, a bio-based acrylic adhesive liquid coating was applied to a 50 μm release layer. The coating was then dried in a 100°C oven for 5 min to obtain a dry film of the adhesive layer. Rheological tests were performed using a TA HR-10 rotational rheometer. The peaks of the loss factor (tanθ) curves of the adhesive layer, measured by temperature scanning at a temperature of -100 to 150°C, a heating rate of 5°C / min, a strain of 0.1%, and a frequency of 1 Hz, were recorded as the glass transition temperatures (Tg1, Tg2) of the adhesive layer.

[0058] 4. Glass transition temperature (Tg) test of copolymer

[0059] Using a comma roller doctor blade, an acrylic copolymer solution was coated onto a 50 μm release layer. The coated layer was then dried in a 100°C oven for 5 minutes to obtain a copolymer dry film with a thickness of 25 μm. The glass transition temperature (Tg) of the copolymer dry film was then measured using DSC (Digital Substances Computing). Measurement apparatus: Netzsch DSC200F3 (manufactured by Netzsch, Germany). Test temperature range: -100 to 120°C, heating rate: 5°C / min.

[0060] 5. Peel force test:

[0061] At 23℃, one side of a 150mm long × 25mm wide adhesive tape strip was reinforced with a 50μm thick Yihua Toray D03 standard BOPET film. The other side was then reinforced onto a stainless steel mirror plate (150mm long × 50mm wide × 2mm thick with a surface roughness of 10nm±10nm) that meets the requirements of GB / T2792 peel test steel plate material. A 2kg roller was used to roll the strip back and forth once on the stainless steel mirror plate with the strip attached at a speed of 300mm / min. After standing for 20 minutes in the test environment, a 180° peel strength test was performed using a tensile tester at a peel speed of 300mm / min. Three samples were tested, and the arithmetic mean of the three test results was taken as the peel force result.

[0062] Residual adhesive determination:

[0063] ◎: Excellent residual adhesive. If the ratio of the area of ​​residual adhesive on the surface of the stainless steel mirror plate after the peel force test of the adhesive layer of the tape sample at 65℃ to the area of ​​the sample peeled off from the steel plate is ≤5%, then the residual adhesive of the sample is judged to be excellent.

[0064] ×: Residual adhesive difference. If the ratio of the area of ​​residual adhesive on the surface of the stainless steel mirror plate after the peel force test of any adhesive layer of the tape sample at 65℃ to the area of ​​the area peeled off from the steel plate is greater than 5%, then the sample is judged to have residual adhesive difference.

[0065] Here, residual adhesive refers to the phenomenon where the adhesive layer cohesion is damaged, and both the substrate and the steel plate surface are covered with the damaged adhesive layer.

[0066] Copper foil discoloration determination:

[0067] ◎: Excellent resistance to copper foil discoloration. If the adhesive layer of the tape sample is bonded to the copper foil and placed at 65℃-90%RH for 72 hours, and the lab value is <, then the sample is judged to have excellent resistance to copper foil discoloration.

[0068] ×: If the resistance to copper foil discoloration is good or bad, the adhesive layer of the tape sample is bonded to the copper foil and placed at 65℃-90%RH for 72h. If the lab value is greater than 0.05, then the resistance to copper foil discoloration of the sample is judged to be poor.

[0069] The performance tests of the bio-based adhesive layers in each comparative example and embodiment are shown in Table 4.

[0070] Table 4

[0071]

[0072] in conclusion:

[0073] In Examples 1-2, the adhesive layer has low low-temperature modulus and good flexibility, appropriate high-temperature modulus, good high-temperature peel strength and cohesion, and no residual adhesive or copper foil discoloration issues.

[0074] In Comparative Examples 1-2, the bio-based acrylic polymers in the formulations were not designed with a block structure. When the low-temperature modulus of the adhesive layer met the requirements, the high-temperature peel strength was low, the cohesion was poor, and it was easy to leave residue.

[0075] In Comparative Example 3, the Tg of the soft segment of the bio-based acrylic block polymer was too low, resulting in a low Tg of the low-temperature segment of the adhesive layer and causing residual adhesive problems.

[0076] In Comparative Example 4, the Tg of the soft segment of the bio-based acrylic block polymer was too high, resulting in an excessively high low-temperature modulus of the adhesive layer, an excessively high Tg of the low-temperature segment, poor low-temperature flexibility, and excessive high-temperature peeling force, which affected reworkability.

[0077] In Comparative Example 5, the acid value of the bio-based acrylic block polymer was too high, causing the copper foil in the adhesive layer to discolor.

[0078] In Comparative Example 6, the hard segment Tg of the bio-based acrylic block polymer was too low, resulting in low high-temperature modulus of the adhesive layer, low peel strength, and residual adhesive problems.

[0079] In Comparative Example 7, the hard segment Tg of the bio-based acrylic block polymer was too high, the adhesive layer height / low temperature modulus was too high, the low temperature flexibility was poor, the adhesive layer was too hard, and the high temperature peel strength was also too low.

[0080] In Comparative Example 8, the proportion of hard segments in the bio-based acrylic block polymer was too high, resulting in an excessively high low-temperature modulus of the adhesive layer, poor low-temperature flexibility, and excessive high-temperature peeling force, which affected reworkability.

[0081] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, technology, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, technology, article, or apparatus.

[0082] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A type of tape for foldable screens, characterized in that: The tape includes an adhesive layer (2), and a release layer is provided on at least one side of the adhesive layer (2); the adhesive layer has at least two glass transition temperatures, a first glass transition temperature of -70 to 30°C and a second glass transition temperature of 0 to 65°C; the adhesive layer (2) comprises a bio-based acrylate copolymer obtained by stepwise block polymerization of RAFT emulsion and a curing agent, wherein the amount of the curing agent is 0.5 to 2.5 wt% of the bio-based acrylate copolymer, the bio-based acrylate copolymer is obtained by block polymerization of acrylate copolymer soft segments and acrylate copolymer hard segments, the glass transition temperature of the acrylate copolymer soft segments is -80 to -40°C, and the glass transition temperature of the acrylate copolymer hard segments is -10 to 60°C.

2. The tape for folding screens according to claim 1, characterized in that: The acrylate copolymer soft segment is polymerized from soft segment functional monomers and soft segment auxiliary monomers. The soft segment functional monomers are one or more of the following: n-butyl acrylate, 2-ethylhexyl acrylate, 2-octyl acrylate, n-octyl acrylate, isooctyl acrylate, isononyl acrylate, isodecanyl acrylate, 2-propylheptyl acrylate, tetrahydrofuran acrylate, methoxyethyl acrylate, caprolactone acrylate, ethoxyethoxyethyl acrylate, methoxy polyethylene glycol acrylate, tridecyl acrylate, hexadecyl acrylate, heptadecanyl acrylate, isooctyl methacrylate, lauryl methacrylate, and dodecyl methacrylate. The soft segment auxiliary monomers are one or more of the following: methyl acrylate, acrylic acid, acrylamide, 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, methacrylic acid, and methacrylamide.

3. The tape for folding screens according to claim 1, characterized in that: The acrylate copolymer hard segment is polymerized from hard segment functional monomers and hard segment auxiliary monomers; the hard segment functional monomers are one or more selected from methyl acrylate, ethyl acrylate, propyl acrylate, isobutyl acrylate, tert-butyl acrylate, trimethylolpropane formal acrylate, isobornyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, isobornyl methacrylate, cyclohexyl methacrylate, and tetrahydrofuran methacrylate; the hard segment auxiliary monomers are one or more selected from acrylic acid, acrylamide, acrylonitrile, 2-hydroxyethyl acrylate, methacrylic acid, 2-hydroxyethyl methacrylate, and methacrylamide.

4. The tape for folding screens according to claim 1, characterized in that: In the bio-based acrylate block copolymer, the mass ratio of acrylate copolymer hard segments to soft segments is 5 / 95 to 50 / 50.

5. The tape for folding screens according to claim 1, characterized in that: The weight-average molecular weight of the bio-based acrylate block copolymer is between 450,000 and 1,800,000.

6. The tape for folding screens according to claim 1, characterized in that: The acid value of the bio-based acrylate copolymer is ≤15.0 mgKOH / g; the storage modulus G′ of the adhesive layer is <200 kPa at -20°C; the storage modulus G′ of the adhesive layer is 8–25 kPa at 65°C; and the ratio tanθ of the loss modulus G″ to the storage modulus G′ of the adhesive layer is 0.4–0.8 at 65°C.

7. A manufacturing process for a folding screen tape as described in any one of claims 1-6, characterized in that: Includes the following steps: The adhesive layer is coated onto the surface of the first release layer, and the second release layer is applied to the other side. After curing, the tape is obtained. The adhesive layer formed by the adhesive layer solution contains at least two glass transition temperatures: the first glass transition temperature Tg1 is -70 to -30℃, and the second glass transition temperature Tg2 is 0 to 65℃.

8. The manufacturing process of a foldable screen tape according to claim 7, characterized in that: Preparation of adhesive layer solution Includes the following steps: S1: Take the functional monomers and auxiliary monomers of the soft segment of acrylate copolymer, emulsifier, deionized water and RAFT reagent, mix them evenly to prepare a nano pre-emulsion; add an initiator under nitrogen protection and react to obtain emulsion A; S2: add the polymerizing monomer for the hard segment of bio-based acrylate block copolymer to emulsion A, continue the polymerization reaction under nitrogen protection, cool down after the reaction is completed, add hydrogen peroxide aqueous solution and sodium metabisulfite aqueous solution to continue the reaction, then cool down, filter, and discharge to obtain emulsion B, spray dry to obtain dry powder, and dissolve in organic solvent to form a bio-based acrylate copolymer solution; S3: stir the bio-based acrylate copolymer solution and curing agent evenly, let stand to defoam, and obtain the adhesive layer solution.

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