Swelling adhesive tape having chemical stability

Abstract

The utility model discloses a kind of swelling adhesive tapes with chemical stability, its structure includes pressure-sensitive adhesive layer, first swelling layer, first primer layer, toughening layer, second primer layer, second swelling layer and non-silicon release coating in turn from top to bottom.The pressure-sensitive adhesive layer uses modified acrylic pressure-sensitive adhesive, insoluble in electrolyte and can keep tackiness;First and second swelling layer are epoxy resin modified polyurethane resin, can contact with electrolyte and occur three-dimensional swelling to fill the gap between battery cell and aluminum shell, while epoxy resin improves the crosslinking density of polyurethane, enhances chemical stability;Toughening layer uses BOPS film, reduces cladding deformation;Primer layer enhances the adhesion between swelling layer and toughening layer, prevents delamination;Non-silicon release coating provides relatively light unwinding force, facilitate automated cladding operation.The adhesive tape can effectively ensure the bonding reliability of lithium battery cell, prevent vibration misplacement short circuit, and have excellent chemical stability.

Description

Technical Field

[0001] This utility model relates to the field of adhesive tape technology, and in particular to a chemically stable swelling adhesive tape. Background Technology

[0002] Cylindrical lithium batteries are widely used in various electronic fields such as laptops, power tools, precision instruments, and power banks due to their small size and high capacity density. During assembly, there is often a large gap between the battery cell and the casing. During use, vibration or bumps can easily cause the cell to shift or misalign. This shifting or misalignment often leads to the cell detaching from the positive and negative electrodes, causing a short circuit and affecting the overall user experience of the cylindrical lithium battery.

[0003] To address the aforementioned issues, patents such as CN 220432689U and CN 220432689U propose wrapping one or more layers of expanding or swellable adhesive tape around the battery cell. This tape expands upon contact with the electrolyte or under certain special conditions, thus securing the battery cell. However, over time, these expanding tapes, due to their simple structure and base material, are prone to dissolving in the electrolyte. Therefore, there is a need to develop a chemically stable swellable adhesive tape. Utility Model Content

[0004] The purpose of this invention is to provide a chemically stable swelling tape to solve the problem that existing swelling tapes are easily dissolved in electrolytes.

[0005] The technical solution to achieve the purpose of this utility model is as follows: This utility model includes a pressure-sensitive adhesive layer, a first swelling layer, a first primer layer, a toughening layer, a second primer layer, a second swelling layer, and a non-silicone release coating layer arranged sequentially from top to bottom.

[0006] Furthermore, the aforementioned pressure-sensitive adhesive layer is a modified acrylic pressure-sensitive adhesive layer.

[0007] Furthermore, the first and second swelling layers mentioned above are epoxy resin modified polyurethane resin layers.

[0008] Furthermore, the toughening layer described above is a BOPS film with a thickness of 12–25 μm.

[0009] Furthermore, the first and second primer layers mentioned above are primer layers for polyurethane.

[0010] Furthermore, the primer layer used for polyurethane employs 3M primer.

[0011] Furthermore, the aforementioned non-silicone release coating is a polyethyleneimine octadecylurea release coating.

[0012] This invention offers several advantages: Compared to existing products, the swelling tape of this invention features a unique structure. Epoxy-modified polyurethane resin is used as the swelling layer, resulting in an excellent swelling rate. The presence of epoxy resin increases the cross-linking density of the polyurethane resin, reducing its dissolution in the electrolyte at high temperatures. Furthermore, the use of BOPS film as a toughening layer reduces the likelihood of deformation during lithium battery cell coating due to the elasticity of the polyurethane. The BOPS film also exhibits micro-swelling properties in the electrolyte. Applying a primer to both sides of the BOPS film effectively reduces delamination between the polyurethane layer and the BOPS film in the electrolyte. Finally, coating the back of the lower swelling layer with a non-silicone release agent provides a lighter unwinding force, ensuring the continuity of lithium battery cell coating in automated equipment. Attached Figure Description

[0013] To make the content of this utility model easier to understand, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein... Figure 1 This is a cross-sectional view of the overall structure of the swelling tape of this utility model.

[0014] In the figure, pressure-sensitive adhesive layer 1, first swelling layer 2, first primer layer 3, toughening layer 4, second primer layer 5, second swelling layer 6, and non-silicone release coating 7 are shown. Detailed Implementation

[0015] See Figure 1 This utility model provides a chemically stable swelling tape, which includes, from top to bottom, a pressure-sensitive adhesive layer 1, a first swelling layer 2, a first primer layer 3, a toughening layer 4, a second primer layer 5, a second swelling layer 6, and a non-silicone release coating 7.

[0016] The pressure-sensitive adhesive layer 1 is a modified acrylic pressure-sensitive adhesive layer. Its number-average molecular weight is between 200,000 and 400,000. When immersed in electrolyte at 85°C for 72 hours, it does not turn white at the edges, does not swell, and does not peel.

[0017] The first swelling layer 2 and the second swelling layer 6 are epoxy resin modified polyurethane resin layers. Their epoxy equivalent is 750-850 g / mol, viscosity is 15000-40000 mPas, and softening point temperature is 110-120℃. The modified polyurethane resin has a molecular weight range of 200,000-300,000, a Shore hardness of 56D, a specific gravity of 1.23, a tensile strength of 35 MPa, and an elongation at break of 425%.

[0018] The toughening layer 4 is a BOPS film with a thickness of 12–25 μm. Specifically, a BOPS film with a thickness of 12 μm is selected.

[0019] The first primer layer 3 and the second primer layer 5 are primer layers for polyurethane. The primer layer for polyurethane uses 3M primer.

[0020] The non-silicone release coating 7 is a polyethyleneimine octadecylurea release coating.

[0021] In use, the swelling tape is wrapped around the outer layer of the lithium battery cell. The outer layer of the lithium battery cell is bonded to the pressure-sensitive adhesive layer 1 of the swelling tape. The pressure-sensitive adhesive layer 1 does not dissolve after being immersed in the electrolyte and retains its adhesiveness, effectively ensuring the reliability of the bond between the swelling tape and the lithium battery cell. Through the contact of the first swelling layer 2 and the second swelling layer 6 with the electrolyte, three-dimensional swelling occurs, filling the gap between the lithium battery cell and the aluminum shell. This prevents the lithium battery cell from misaligning and short-circuiting under vibration. Simultaneously, the epoxy resin in the first swelling layer 2 and the second swelling layer 6 increases the cross-linking density of the polyurethane resin, providing a certain degree of chemical stability and significantly reducing the stress on the polyurethane resin under high-temperature conditions. The material dissolves in the electrolyte. Using a BOPS film with micro-swelling properties as the toughening layer 4 can reduce the possibility of deformation during the coating of lithium battery cells due to the elasticity of polyurethane. At the same time, by coating the toughening layer 5 with the first primer layer 3 and the second primer layer 5 on both sides, the adhesion between the first swelling layer 2, the second swelling layer 6 and the toughening layer 4 is increased, which can effectively reduce the delamination of the first swelling layer 2, the second swelling layer 6 and the toughening layer 4 in the electrolyte. Coating the back of the second swelling layer 6 with a non-silicone release coating 7 can give the swelling tape a lighter unwinding force, which facilitates continuous coating operations by automated equipment.

[0022] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above descriptions are merely specific embodiments of this utility model and are not intended to limit this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A chemically stable swelling tape, characterized in that: It includes, from top to bottom, a pressure-sensitive adhesive layer (1), a first swelling layer (2), a first primer layer (3), a toughening layer (4), a second primer layer (5), a second swelling layer (6), and a non-silicone release coating layer (7).

2. The chemically stable swelling tape according to claim 1, characterized in that: The pressure-sensitive adhesive layer (1) is a modified acrylic pressure-sensitive adhesive layer.

3. The chemically stable swelling tape according to claim 1, characterized in that: The first swelling layer (2) and the second swelling layer (6) are epoxy resin modified polyurethane resin layers.

4. The chemically stable swelling tape according to claim 1, characterized in that: The toughening layer (4) is a BOPS film with a thickness of 12-25 μm.

5. The chemically stable swelling tape according to claim 1, characterized in that: The first primer layer (3) and the second primer layer (5) are primer layers for polyurethane.

6. The chemically stable swelling tape according to claim 5, characterized in that: The primer layer used for polyurethane is a 3M primer.

7. The chemically stable swelling tape according to claim 1, characterized in that: The non-silicone release coating (7) is a polyethyleneimine octadecylurea release coating.

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