EP4605235A1

EP4605235A1 - Double-sided adhesive tape with symmetrical performance and reworkability

Info

Publication number: EP4605235A1
Application number: EP23797727.7A
Authority: EP
Inventors: Wei Wang; Xiao CHENG; Renke Bargmann; Min Cao; Qi Yu
Original assignee: Tesa SE
Current assignee: Tesa SE
Priority date: 2022-10-21
Filing date: 2023-10-23
Publication date: 2025-08-27
Also published as: WO2024084101A1; CN117946597A

Abstract

The present invention discloses a double-sided adhesive tape with symmetrical performance and reworkability, which includes a substrate, including an elastic layer, or including an elastic layer and a foam layer arranged in a stacked manner; and an adhesive layer arranged on both sides of the substrate. Since the elastic layer can increase the strength and elasticity of the adhesive tape, the adhesive tape has good impact resistance. The adhesive tape has good deformation ability, and has good caulking or infiltration performance on an adhesive surface, making it easy for the adhesive tape to contact and bond with an uneven surface, thereby increasing the adhesive force. By introducing an elastic layer into the substrate, both sides of the adhesive tape have more balanced properties, avoiding the problem of unbalanced adhesive force on both sides of the adhesive tape, and improving the overall reworkability of the adhesive tape at the same time, thereby providing a more convenient way for the recycling and reuse of related electronic components.

Description

Double-sided adhesive tape with symmetrical performance and reworkability

TECHNICAL FIELD

[0001] The present disclosure relates to the field of adhesive tapes, in particular to a doublesided adhesive tape with symmetrical performance and reworkability.

BACKGROUND

[0002] Adhesive tape is often used for bonding in production and life. As the application fields continue to increase, the performance requirements for adhesive tape are getting higher. For example, in the field of electrical appliances and electronic equipment, the adhesive tape is often used to achieve bonding between devices. Due to the difference in shapes and structures of the devices, the performance requirements for the adhesive tapes are also different, and the structure and performance of the adhesive tapes need to meet a variety of requirements, e.g., having sufficient adhesive property. However, most existing foam adhesive tapes use polyethylene terephthalate film (PET film) as a reinforcing substrate, but the performance of the adhesive layers on both sides of the adhesive tape structure is unbalanced or the conformability is insufficient, thereby affecting the use of the adhesive tape. At the same time, in some application scenarios, some more expensive components need to be disassembled and reused. Therefore, the reworkability of the adhesive tape is increasingly valued. However, to a large extent, many existing adhesive tape structures cannot meet the requirements of reworkability.

SUMMARY

[0003] The purpose of embodiments of the present disclosure is to provide a double-sided adhesive tape with symmetrical performance and reworkability which can solve the problems of unbalanced performance on both sides of adhesive tapes in prior art, insufficient conformability, and inability to meet the needs of reworkability.

[0004] In a first aspect, an embodiment of the present disclosure provides a double-sided adhesive tape with symmetrical performance and reworkability, including: a substrate, including an elastic layer, or including an elastic layer and a foam layer arranged in a stacked manner; and an adhesive layer arranged on both sides of the substrate.

[0005] Among them, the elastic layer is arranged on one side of the foam layer; or the elastic layer is arranged on both sides of the foam layer.

[0006] Among them, the foam layer is arranged on one side of the elastic layer; or the foam layer is arranged on both sides of the elastic layer.

[0007] Among them, both the elastic layer and the foam layer are plural, and a plurality of elastic layers and a plurality of foam layers are arranged alternately in a stacked manner.

[0008] Among them, the elastic layer has a thickness in a range from 5 pm to 100 pm.

[0009] Among them, the adhesive tape has a thickness in a range from 100 pm to 500 pm; and the adhesive layer has a thickness in a range from 10 pm to 150 pm, preferably a thickness in a range from 30 pm and 100 pm, and more preferably a thickness in a range from 30 pm to 60 pm.

[0010] Among them, the elastic layer includes at least one selected from a group consisting of a bio-based elastic film, a polyurethane elastic material, a styrene elastic material, a polyolefin elastic material and a polyamide elastic material.

[0011] Among them, the foam layer includes at least one selected from a group consisting of polyacrylate foam, polyethylene foam, chloroprene rubber foam, ethylene-vinyl acetate copolymer foam, styrene-butadiene rubber foam and ethylene propylene terpolymer foam; and/or the adhesive layer includes at least one selected from a group consisting of polyacrylate, rubber, polyurethane and silicone; and/or the adhesive layer is a foaming adhesive layer.

[0012] Among them, the adhesive tape further includes: a release film arranged on a side of the adhesive layer away from the substrate.

[0013] In a second aspect, an embodiment of the present disclosure provides an electronic device, including: the adhesive tape according to any one of the above embodiments; and a structural component connected to the adhesive layer of the adhesive tape.

[0014] In the adhesive tape according to an embodiment of the present disclosure, the substrate includes an elastic layer, or includes an elastic layer and a foam layer arranged in a stacked manner; and an adhesive layer is arranged on both sides of the substrate. Since the elastic layer can increase the strength and elasticity of the adhesive tape, the adhesive tape has good impact resistance. The adhesive tape has good deformation ability, and has good caulking or infiltration performance on an adhesive surface, making it easy for the adhesive tape to contact and bond with an uneven surface, thereby increasing the adhesive force. By introducing an elastic layer into the substrate, both sides of the adhesive tape have more balanced properties, avoiding the problem of unbalanced adhesive force on both sides of the adhesive tape. Meanwhile, the elastic layer can be stretched well and has good reworkability, thereby solving the problem of components not being reusable.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Fig. 1 is a schematic view showing an adhesive tape according to an embodiment of the present disclosure.

[0016] Fig. 2 is a schematic view showing an adhesive tape according to a further embodiment of the present disclosure.

[0017] Fig. 3 is a schematic view showing an adhesive tape according to a yet embodiment of the present disclosure.

[0018] Fig. 4 is a schematic view showing an adhesive tape according to a yet embodiment of the present disclosure.

[0019] Fig. 5 is a schematic view showing an adhesive tape according to a yet embodiment of the present disclosure.

[0020] Fig. 6 is a schematic view showing an adhesive tape without an elastic layer.

[0021] Fig. 7 is a schematic view showing adhesive tape-bonded structural parts.

[0022] Fig. 8 is a schematic view showing an adhesive tape according to an embodiment of the present disclosure.

[0023] Fig. 9 is a schematic view showing a further adhesive tape without an elastic layer.

[0024] Reference Numbers

[0025] 10 substrate; 11 elastic layer; 12 foam layer; 20 adhesive layer; 30 release film; 40 polyethylene terephthalate layer; 50 structural part.

DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present disclosure will be described hereinafter in conjunction with the drawings in the embodiments of the present disclosure in a clear and complete manner. Obviously, the following embodiments relate to a part of, rather than all of, the embodiments of the present disclosure. Based on these embodiments, a person skilled in the art may, without any creative effort, obtain the other embodiments, which also fall within the scope of the present disclosure.

[0027] The terms “first”, “second” and the like in the description and claims of the present disclosure are used to distinguish similar objects and are not used to describe a specific order or sequence. It is to be understood that the data used in the above terms are interchangeable under appropriate circumstances so that embodiments of the present disclosure can be practiced in sequences other than those illustrated or described herein. In addition, “and/or” in the description and claims indicates at least one of the connected objects, and the character 7” generally indicates that the related objects are in an “or” relationship.

[0028] The double-sided adhesive tape with symmetrical performance and reworkability provided by the embodiment of the present disclosure will be described in detail through specific embodiments and application scenarios as shown in Figs. 1 to 9.

[0029] As shown in Figs. 1 to 5, the adhesive tape according to the embodiment of the present disclosure includes: a substrate 10 and an adhesive layer 20. The substrate 10 may include an elastic layer, or the substrate 10 may include an elastic layer 11 and a foam layer 12 arranged in a stacked manner. The substrate 10 can be an elastic layer, or the substrate 10 can be an elastic layer 11 and a foam layer 12 arranged in a stacked manner, and an adhesive layer 20 can be arranged on both sides of the substrate 10. The foam layer 12 has pores, and the foam layer 12 can be elastic. The side of the elastic layer 11 proximate to the foam layer 12 can be embedded in the pores of the foam layer 12, to enhance the bonding strength between the elastic layer 11 and the foam layer 12 and prevent them from being easily separated. The foam layer 12 may be polyacrylate foam, and the elastic layer 11 may be a nylon elastic material layer or a polyurethane elastic material layer.

[0030] The layer number of the elastic layer 11 and the foam layer 12 can be selected according to the actual situation. The elastic layer 11 and the foam layer 12 can be singular or plural. For example, the elastic layer 11 is singular and the foam layer 12 is singular; the elastic layer 11 is plural and the foam layers 12 is plural, in which a plurality of elastic layers 11 and a plurality of foam layers 12 can be arranged alternately in a stacked manner; the elastic layers 11 is singular and the foam layers 12 is plural, in which the elastic layer 11 can be arranged between two adjacent foam layers 12; or the elastic layer 11 is plural and the foam layer 12 is singular, and the foam layer 12 can be arranged between two adjacent elastic layers 11 . The substrate 10 can be formed by the elastic layer 11 and the foam layer 12 arranged in a stacked manner. The specific thickness of the adhesive layer 20 and the substrate 10 can be selected according to actual conditions.

[0031] In the adhesive tape according to the embodiment of present disclosure, since the elastic layer 11 can increase the strength and elasticity of the adhesive tape, the adhesive tape has good impact resistance. The adhesive tape has good deformation ability, and has good caulking or infiltration performance on an adhesive surface, making it easy for the adhesive tape to contact and bond with an uneven surface, thereby increasing the adhesive force. By introducing an elastic layer 11 into the substrate 10, both sides of the adhesive tape have more balanced properties, thus the difference in performance between two sides is small, thereby avoiding the unbalanced adhesive force on both sides of the adhesive tape.

[0032] In some embodiments, as shown in Fig. 1 , an elastic layer 11 may be arranged on one side of the foam layer 12. For example, the elastic layers 11 is singular and the foam layers 12 is singular, in which the elastic layer 11 is arranged on one side of the foam layer 12; or the elastic layers 11 is plural and the foam layers 12 is singular, in which a plurality of elastic layers 11 are arranged on the same side of the foam layer 12, and the elastic layer 11 makes both sides of the adhesive tape to have more balanced properties, thereby balancing the adhesive force on both sides of the adhesive tape.

[0033] In other embodiments, as shown in Fig. 3, elastic layers 11 may be arranged on both sides of the foam layer 12. For example, the elastic layers 11 is plural, and the foam layers 12 is singular, in which at least one elastic layer 11 can be arranged on both sides of the foam layer 12. By arranging the elastic layer 11 on both sides of the foam layer 12, the impact resistance and caulking performance of the adhesive tape can be enhanced, so that the adhesive tape has better application performance and is easier to be removed to recycle the corresponding components.

[0034] Optional, the foam layer 11 is arranged on one side of the elastic layer 12. For example, the elastic layer 11 is singular and the foam layer 12 is singular, in which the foam layer 12 is arranged on one side of the elastic layer 11 , and the elastic layer 11 makes both sides of the adhesive tape have more balanced performance, so as to balance the adhesive force on both sides of the adhesive tape.

[0035] In the embodiment of the present disclosure, as shown in Fig. 2, the foam layers 12 are arranged on both sides of the elastic layer 11 . For example, the foam layers 12 is plural and the elastic layers 11 is singular, in which at least one foam layer 12 can be arranged on both sides of the elastic layer 11 . By arranging the elastic layer 11 between the foam layers 12, the impact resistance and caulking performance of the adhesive tape can be enhanced, so that the adhesive tape has better application performance and is easier to be removed to recycle the corresponding component.

[0036] Optionally, as shown in Figs. 4 to 5, both the elastic layer 11 and the foam layer 12 may be plural, in which a plurality of elastic layers 11 and a plurality of foam layers 12 may be arranged alternately in a stacked manner. For example, both the number of the elastic layer 11 and the number of the foam layer 12 may be two, in which the elastic layer 11 , the foam layer 12, the elastic layer 11 and the foam layer 12 can be arranged in sequence in a stacked manner. As shown in Fig. 5, the number of the elastic layer 11 is two and the number of the foam layer 12 may be three, in which the foam layer 12, the elastic layer 11 , the foam layer 12, the elastic layer 11 and the foam layer 12 may be arranged alternately in a stacked manner. As shown in Fig. 4, the number of the elastic layer 11 is three and the number of the foam layers 12 can be two, in which the elastic layer 11 , the foam layer 12, the elastic layer 11 , the foam layer 12 and the elastic layer 11 may be arranged in sequence in a stacked manner, and the specific thickness and material of each elastic layer 11 and foam layer 12 can be reasonably selected according to actual needs. By alternately arranging the elastic layer 11 and the foam layer 12, the overall impact resistance of the adhesive tape is enhanced, and the adhesive tape has good deformation ability, making it easy for the adhesive tape to contact and bond with an uneven surface, thereby increasing the adhesive force, so that both sides of the adhesive tape have a more balanced performance and removable performance.

[0037] Optionally, the elastic layer 11 may have a thickness in a range from 5 pm to 100 pm. For example, the elastic layer 11 may have a thickness in a range from 5 pm, 50 pm or 100 pm. The specific thickness can be reasonably selected according to the thickness of the adhesive tape and the impact resistance requirements.

[0038] Alternatively, the adhesive tape may have a thickness in a range from 100 pm to 500 pm, and the adhesive layer 20 may have a thickness in a range from 10 pm to 150 pm. For example, the adhesive layer 20 may have a thickness in a range from 30 pm or 80 pm, and the adhesive tape may have a thickness in a range from 300 pm. The adhesive layer 20 may have a thickness preferably in a range from 30 pm to 100 pm, more preferably in a range from 30 pm to 60 pm. [0039] In some embodiments, the elastic layer 11 may include at least one selected from a group consisting of a bio-based elastic film, a polyurethane elastic material, a styrene elastic material, a polyolefin elastic material and a polyamide elastic material. For example, the elastic layer 11 may be a bio-based elastic film, a polyurethane elastic material layer, a styrene elastic material layer, a polyolefin elastic material layer, or a polyamide elastic material layer. The elastic layer 11 may be at least two material layers selected from a polyurethane elastic material layer, a styrene elastic material layer, a polyolefin elastic material layer and a polyamide elastic material layer arranged in a stacked manner. For example, the elastic layer 11 can be a bio-based elastic film and a polyurethane elastic material layer arranged in a stacked manner, and the elastic layer 11 can be a polyurethane elastic material layer and polyolefin elastic material arranged in a stacked manner. The elastic layer 11 may be formed from a mixture of at least two materials selected from a group consisting of a polyurethane elastic material, a styrene elastic material, a polyolefin elastic material and a polyamide elastic material. For example, the elastic layer 11 may be formed from a mixture of a polyurethane elastic material and a polyamide elastic material.

[0040] Optional, the foam layer 12 may include at least one selected from a group consisting of polyacrylate foam, polyethylene foam, chloroprene rubber foam, ethylene-vinyl acetate copolymer foam, styrene-butadiene rubber foam and ethylene propylene terpolymer foam. For example, the foam layer 12 may be polyacrylate foam, polyethylene foam, chloroprene rubber foam, ethylene-vinyl acetate copolymer foam, styrene-butadiene rubber foam or ethylene propylene terpolymer foam. The foam layer 12 may at least two foams selected from polyacrylate foam, polyethylene foam, chloroprene rubber foam, ethylene-vinyl acetate copolymer foam, styrene-butadiene rubber foam or ethylene propylene terpolymer foam arranged in a stacked manner. For example, the foam layer 12 may be polyacrylate foam and polyethylene foam arranged in a stacked manner, and the foam layer 12 may be polyacrylate foam and styrene-butadiene rubber foam arranged in a stacked manner. In the process of forming the substrate 10, an elastic material layer can be coated on the foam layer 12 and then cured to form the elastic layer 11 . For example, a polyurethane material layer can be coated on the foam layer 12 and then cured to form the elastic layer 11 . Since the foam layer 12 has pores, the elastic layer 11 can be embedded in the pores of the foam layer 12 to enhance the bonding strength between the elastic layer

11 and the foam layer 12 and prevent them from being easily separated. [0041] Optionally, the adhesive layer 20 may include at least one of polyacrylate, rubber, polyurethane, and silicone. For example, the adhesive layer 20 may be polyacrylate, polyurethane, or silicone.

[0042] Optionally, the adhesive layer 20 may be a foam adhesive layer. As shown in Fig. 8, the substrate 10 is an elastic layer, in which an adhesive layer 20 is arranged on both sides of the substrate 10; and the adhesive layer 20 can be a foam adhesive layer. The adhesive layer 20 can be used as a foam layer and an adhesive layer at the same time, which has an adhesive effect and is beneficial to reducing the thickness in a range from the adhesive tape.

[0043] Optionally, as shown in Figs. 1 to 5, the adhesive tape may also include: a release film 30, and the release film 30 may be arranged on one side of the adhesive layer 20 away from the substrate 10. For example, the release film 30 may be arranged on one side of one or two adhesive layer 20 away from the substrate 10. The release film 30 can protect the adhesive layer 20, reduce the contact between the adhesive layer 20 and the external environment, and avoid contamination or damage by the external environment. During use, the release film 30 can be separated from the adhesive layer 20 so that the adhesive layer 20 can be bonded to the surface to be bonded.

[0044] As shown in Fig. 6, the substrate includes a foam layer 12 and a polyethylene terephthalate layer (PET layer) 40 arranged in a stacked manner, and the adhesive layer 20 is arranged on both sides of the substrate. As shown in Fig. 1 , the substrate 10 includes an elastic layer 11 and a foam layer 12 arranged in a stacked manner, and adhesive layers 20 are arranged on both sides of the substrate 10. The adhesive tape shown in Fig. 6 is used as a comparative example, and the adhesive tape shown in Fig. 1 is used as an example. The properties of the two tapes were tested respectively, and the specific test results are shown in Table 1 .

[0045] Example 1

[0046] As shown in Fig. 1 , the adhesive tape of Example 1 includes from top to bottom: a 50 pm thick release film 30; a 50 pm thick polyacrylate adhesive layer (brand: Tesa20), i.e., an adhesive layer 20; a 30 pm thick polyurethane elastic film (elastic layer 11 ) processed by an extrusion process; a 170 pm thick polyacrylate foam layer (foam layer 12); and a 50 pm thick polyacrylate adhesive layer (brand: Tesa20), i.e., an adhesive layer 20. The layers are attached using a lamination process, in which corona treatment was performed between the polyurethane elastic film and the adhesive layer, between the polyurethane elastic film and the polyacrylate foam layer, and between the polyacrylate foam layer and the adhesive layer, so as to improve interface adhesion.

[0047] As shown in Fig. 6, the adhesive tape of Comparative Example 1 includes from top to bottom: a 50 pm thick release film 30; a 60 pm thick polyacrylate adhesive layer (brand: Tesa20), i.e., an adhesive layer 20; a 12 pm thick polyethylene terephthalate layer (PET layer) 40; a 170 pm thick polyacrylate foam layer (foam layer 12); and a 60 pm thick polyacrylate adhesive layer (brand: tesa20), i.e., an adhesive layer 20. The layers are attached using a lamination process, in which corona treatment was performed between the PET layer and the adhesive layer, between the PET layer and the polyacrylate foam layer, and between the polyacrylate foam layer and the adhesive layer, so as to improve interface adhesion.

[0048] The method for testing the surface stripping force of the adhesive tape in Example 1 is as follows.

[0049] The adhesive tape was cut into 20 mm wide strips along the machine direction and reinforced with a 36 pm thick PET layer (for example: if the test tape has a release film surface, the 36 pm thick reinforcement film is attached to the surface of the adhesive tape away from the release film, vice versa.).

[0050] At room temperature (23+/-1 °C, 50+/-5% R.H.), Tesa steel plate used in the test was wiped clean with acetone and kept at room temperature for 5 minutes. Then a hand-held rubber roller is used to gently attach the tested tape to the test steel plate, and the air between the adhesive tape and the steel plate was evacuated. The sample was then rolled using an automatic rolling machine, in which the rolling condition was that a 4 kg steel rolling wheel rolled back and forth five times at a speed of 10 m/min. Then within 1 to 2 minutes thereafter, a Zwick tensile machine was used to peel off the adhesive tape from the steel plate at an angle of 180° at a speed of 300 mm/min, and the average force value read by the testing software was recorded and converted into N/cm. Among them, each sample requires 3 parallel samples.

[0051] The method for testing the impact resistance of the adhesive tape in Example 1 is as follows.

[0052] In this test, two polycarbonate board of different sizes (PC boards, in which one is a square cover plate and the other is a square frame with a hollow in the middle) were used. Before the test, the PC boards used were wiped clean with ethanol and kept at room temperature (23+/-1 °C, 50+/- 5% R.H.) for at least 2 hours.

[0053] A laser die-cutting equipment was used to cut the adhesive tape into a square frame shape with four continuous sides (outer side length is 33 mm, inner side length is 29 mm, and width of the four frames is 2 mm), and the frame adhesive tape was attached between two PC boards side by side and the attached surface bubbles was evacuated. The adhesive tape was then fully activated using a press (activation conditions: 248 Newtons, 5 seconds) and left at room temperature for 24 hours. Then, DuPont impact testing equipment was used to conduct impact testing on the sample at room temperature (divided into horizontal XY direction and vertical Z direction, use 150 g weight as impact load, increase the height every 5 cm until the sample fails), and the height of the sample before failure was recorded and converted into joules (E (energy, joules) = m (weight mass 0.15 kg) * g (gravitational acceleration) h (height m)).

[0054] The method for testing the reworkability of the adhesive tape in Example 1 is as follows.

[0055] The test tape was cut into strips with a width of 10 mm in the machine direction for later use. At room temperature (23+/-1 °C, 50+/-5% R.H.), ASTM steel plate used in the test was wiped clean with acetone and leave it at room temperature for 5 minutes.

[0056] A hand-held rubber roller was used to gently attach the 10 mm wide adhesive tape strip to the ASTM steel plate, while ensuring that the air bubbles between the adhesive tape and the steel plate have been evacuated. Each side of the adhesive tape was guaranteed to have 3 to 5 parallel test samples. The sample was then rolled using an automatic rolling machine, in which the rolling condition was that a 4 kg steel rolling wheel rolled back and forth five times at a speed of 10 m/min. Then the steel plate with the adhesive tape attached was put into a test oven at a temperature of 85 degrees Celsius and a relative humidity of 85% for aging for 72 hours. Afterwards, the steel plate was taken out of the oven and cooled at room temperature for at least 2 hours. The adhesive tape attached to the steel plate was removed by hand from the steel plate at different angles and speeds, to observe whether the adhesive tape will break or leave obvious traces on the steel plate during this process. If there are no breaks or obvious traces, it is recorded as easy to rework, otherwise it is recorded as difficult to rework.

[0057] The method for testing the caulking and infiltration performance of the adhesive tape in

Example 1 is as follows. [0058] This test used glass plates printed with a cross-shaped ink of specific thicknesses (5 pm,

10 pm, 20 pm) and glass plates of the same size without ink as test plates. Before use, they were tested at room temperature (23+/-1 °C, 50 +/-5% R.H.), the protective film was removed from the surface of the glass plate used in the test, and wiped clean to remove any dust or dirt on the surface with a lint- free cloth.

[0059] During the test, a hand-held rubber roller was used to attach the adhesive tape to a glass plate with cross-shaped ink, the release film on the other surface of the adhesive tape was removed, and at the same time another piece without ink was attached to the surface of the adhesive tape. The adhesive tape is then activated using a press (activation conditions: 360 N, 10 seconds) and stored at room temperature for 24 hours. Then a microscope was used to observe the ratio of the bright edge of the ink (bubble area, incomplete infiltration area), in which the lower the ratio, the better the infiltration effect of the adhesive tape.

Table 1 : Test results for the performance of the adhesive tape.

- n - [0060] From the performance test results of Comparative Example 1 and Example 1 in Table 1 , it can be seen that in Example 1 of the present disclosure, the stripping force on both sides of the adhesive tape is balanced, and the adhesive force on both sides of the adhesive tape is balanced; and in Comparative Example 1 , the difference in the stripping force on both sides of the adhesive tape is large, and the adhesive force on both sides of the adhesive tape is uneven. In Example 1 of the present disclosure, there are few bubbles between the adhesive tape and the bonding surface, and the caulking and infiltration effects are good; and in Comparative Example 1 , there are many bubbles between the adhesive tape and the bonding surface, and the caulking and infiltration effects are poor. By adding an elastic layer to the substrate, the adhesive force on both sides of the adhesive tape can be balanced, the caulking and infiltration capabilities of the adhesive tape can be enhanced, and it is easy to rework. The adhesive tape in Example 1 of the present invention can be easily removed during rework maintenance without any residual glue; the adhesive tape in Comparative Example 1 will leave residual glue during rework maintenance.

[0061] Example 2

[0062] As shown in Fig. 8, the adhesive tape of Example 2 includes from top to bottom: a 50 pm thick release film 30; a 140 pm thick polyacrylate foam adhesive layer (brand: Tesa30), i.e., an adhesive layer 20; a 30 pm thick polyurethane elastic film (substrate 10) processed by an extrusion process; and a 140 pm thick polyacrylate foam layer (brand: Tesa30), that is, an adhesive layer 20. The layers were attached using a lamination process, in which corona treatment was performed between the polyurethane elastic film and the foam rubber layer to improve the interface adhesion.

[0063] As shown in Fig. 9, the adhesive tape of Comparative Example 2 includes from top to bottom: a 50 pm thick release film 30; a 140 pm thick polyacrylate foam adhesive layer (brand: Tesa30), i.e., an adhesive layer 20; a 23 pm thick polyethylene terephthalate layer (PET layer) 40; and a 140 pm thick polyacrylate foam adhesive layer (brand: Tesa30), i.e., an adhesive layer 20. The layers were attached using a lamination process, in which corona treatment was performed between the PET layer and the foam rubber layer to improve the interface adhesion.

[0064] The specific test method in Example 1 is also used in Example 2, in which a PC board is added to the board used in the stripping force test. The specific method is as follows:

[0065] The adhesive tape was cut into 20 mm wide strips along the machine direction and reinforced with a 36 pm thick PET layer (for example: if the test tape has a release film surface, the 36 pm thick reinforcement film is attached to the surface of the adhesive tape away from the release film, vice versa.).

[0066] At room temperature (23+/-1 °C, 50+/-5% R.H.), the PC board used in the test was wiped clean with ethanol and left at room temperature for at least 2 hours. Then a hand-held rubber roller is used to gently attach the tested adhesive tape to the test PC board, and the air between the adhesive tape and the PC board was evacuated. The sample was then rolled using an automatic rolling machine, in which the rolling condition was that a 4 kg steel rolling wheel rolled back and forth five times at a speed of 10 m/min. Then within 1 to 2 minutes thereafter, a Zwick tensile machine was used to peel off the adhesive tape from the steel plate at an angle of 180° at a speed of 300 mm/min, and the average force value read by the testing software was recorded and converted into N/cm. Among them, each sample requires to be tested in 3 parallel samples.

Table 2: Test results for the performance of the adhesive tape.

[0067] From the performance test results of Comparative Example 2 and Example 2 in Table 2, it can be seen that the adhesive force of the adhesive tape on the steel plate and PC board in the structure of Example 2 of the present disclosure is higher and the performance is better; at the same time, in Example 2, the introduction of the elastic layer can further improve the reworkability of the adhesive tape and facilitate the recycling and reuse of related electronic devices.

[0068] Example 3

[0069] As shown in Fig. 1 , the adhesive tape of Example 3 includes from top to bottom: a 50 pm thick release film 30; a 60 pm thick polyacrylate adhesive layer (brand: Tesa20), i.e., an adhesive layer 20; a 12 pm thick bio-based elastic film (elastic layer 11); a 170 pm thick polyacrylate foam layer (foam layer 12); and a 60 pm thick polyacrylate adhesive layer (brand: tesa20), i.e., an adhesive layer 20. The layers are attached using a lamination process, in which corona treatment was performed between the bio-based elastic film and the adhesive layer, between the bio-based elastic film and the polyacrylate foam layer, and between the polyacrylate foam layer and the adhesive layer, so as to improve interface adhesion.

[0070] The bio-based elastomer comes from Arkema (China) Investment Co., Ltd., and its trademark name is Pebax@Rnew series of products, in which it is a partially bio-based renewable elastomer, and its bio-based is derived from castor oil. Castor oil is produced from castor beans (a non-edible plant) and is used in the synthesis of monomers. The bio-based content of bio-based elastomer range from 30% to 60%.

[0071] As shown in Fig. 6, the adhesive tape of Comparative Example 1 includes from top to bottom: a 50 pm thick release film 30; a 60 pm thick polyacrylate adhesive layer (brand: tesa20), i.e., an adhesive layer 20; a 12 pm thick polyethylene terephthalate layer (PET layer) 40; a 170 pm thick polyacrylate foam layer (foam layer 12); and a 60 pm thick polyacrylate adhesive layer (brand: tesa20), i.e., an adhesive layer 20. The layers are attached using a lamination process, in which corona treatment was performed between the PET layer and the adhesive layer, between the PET layer and the polyacrylate foam layer, and between the polyacrylate foam layer and the adhesive layer, so as to improve interface adhesion.

[0072] The method for testing the warpage resistance of the adhesive tape in Example 3 is as follows.

[0073] Anti-warping test (24 hours later):

[0074] At room temperature (23+/-1 °C, 50+/-5% R.H.), the aluminum plate and PC board used in the test was wiped clean with acetone and ethanol respectively, and left at room temperature for 5 minutes and more than 2 hours respectively.

[0075] During the test, a rubber roller was first used to attach the test adhesive tape to the aluminum plate, to remove the air bubbles between the adhesive tape and the plate during the process. Then the adhesive tape was trimmed along the frame of the aluminum plate to the same size as the aluminum plate. Then a 4 kg portable steel roller was used to attach the aluminum plate with doublesided foam to the middle of the PC board, to remove the air bubbles between the adhesive tape and the PC board. The sample was then rolled using an automatic rolling machine, in which the rolling condition was that a 4 kg steel rolling wheel rolled back and forth two times at a speed of 10 m/min, and the sample was stored at room temperature for 24 hours. [0076] Afterwards, the sample was stuck in the corresponding test fixture so that the test plate is in a bent state with an angle of 30 degrees. The fixture and sample were put into a test environment oven at 60°C/90% R.H. for 24 hours. Finally, the fixture was taken out of the oven, and the warping height on both sides of the aluminum plate was measured by a small steel ruler and the sum was recorded as the test result. The lower the result value, the better the warpage resistance.

[0077] For other test methods in this Example 3, refer to Example 1 .

Table 3: Test results for the performance of the adhesive tape.

[0078] From the performance test results of Comparative Example 1 and Example 3 in Table 3, it can be seen that compared with Comparative Example 1 , Example 3 using a bio-based elastic film not only has the same impact performance as Comparative Example 1 , but also has more symmetrical bonding properties on both sides thereof, and the reworkability and anti-warping performance are also better. Therefore, Example 3 can not only meet the needs of actual application scenarios, but can also utilize its excellent reworkability to reuse some components, thereby reducing costs. In addition, due to the introduction of bio-based materials, Example 3 can reduce dependence on and use of petrochemicals, further reduce damage to the environment, and play a role in protecting the environment. [0079] As shown in Fig. 7, an embodiment of the present disclosure also provides an electronic device, including: the adhesive tape described in the above embodiment and the structural member 50, in which the adhesive layer 20 of the adhesive tape is connected to the structural member 50. For example, the two adhesive layers 20 of the adhesive tape can be connected to the corresponding structural members 50 respectively, so that the two structural members 50 can be bonded together through the adhesive tape. For example, the number of structural members 50 is two, in which one structural member 50 is a battery cover of the electronic device, and the other structural member 50 is a frame of the electronic device, in which the battery cover and the frame can be bonded together through adhesive tape. Adhesive tape can be used for bonding lenses, back covers and other components of electronic devices. The electronic devices can be mobile phones, computers, tablets, cameras, watches, wearable devices, etc.

[0080] The embodiments of the present disclosure have been described above with reference to the accompanying drawings, but the present disclosure is not limited to the above specific embodiments, and the above specific embodiments are merely illustrative, and not restrictive. Without departing from the scope of the present disclosure and the scope of protection of the claims, a person skilled in the art can made many variations in light of the present disclosure, all of which fall into the protection of the present disclosure.

Claims

Claims double-sided adhesive tape with symmetrical performance and reworkability, comprising: a substrate, comprising an elastic layer, or comprising an elastic layer and a foam layer arranged in a stacked manner; and an adhesive layer arranged on both sides of the substrate. he adhesive tape of claim 1 , wherein the elastic layer is arranged on one side of the foam layer; or the elastic layer is arranged on both sides of the foam layer. he adhesive tape of claim 1 , wherein the foam layer is arranged on one side of the elastic layer; or the foam layer is arranged on both sides of the elastic layer. he adhesive tape of claim 1 , wherein both the elastic layer and the foam layer are plural, and a plurality of elastic layers and a plurality of foam layer are arranged alternately in a stacked manner. he adhesive tape of claim 1 , wherein the elastic layer has a thickness in a range from 5 pm to 100 pm. he adhesive tape of claim 1 , wherein the adhesive tape has a thickness in a range from 100 pm to 500 pm, and the adhesive layer has a thickness in a range from 10 pm to 150 pm. he adhesive tape of claim 1 , wherein the elastic layer comprises at least one selected from a group consisting of a bio-based elastic film, a polyurethane elastic material, a styrene elastic material, a polyolefin elastic material and a polyamide elastic material. he adhesive tape of claim 1 , wherein the foam layer comprises at least one selected from a group consisting of polyacrylate foam, polyethylene foam, chloroprene rubber foam, ethylene-vinyl acetate copolymer foam, styrene-butadiene rubber foam and ethylene propylene terpolymer foam; and/or wherein the adhesive layer comprises at least one selected from a group consisting of polyacrylate, rubber, polyurethane and silicone; and/or wherein the adhesive layer is a foaming adhesive layer. he polishing device of claim 1 , further comprising: a release film arranged on a side of the adhesive layer away from the substrate. An electronic device, comprising: the adhesive tape of any one of claims 1 to 9; and structural members connected to the adhesive layer of the adhesive tape.