Flame-retardant insulating pressure-sensitive adhesive tape for external protection of power battery

Abstract

The utility model discloses a flame-retardant insulating pressure-sensitive adhesive tape for external protection of a power battery. The flame-retardant insulating pressure-sensitive adhesive tape comprises a first base material layer, a first primer layer, a first bonding layer, a second primer layer, a second base material layer, a second bonding layer and a release layer which are sequentially laminated, wherein the first bonding layer is a silica gel pressure-sensitive adhesive layer. The utility model provides the power battery external protection flame-retardant insulating pressure-sensitive adhesive tape with a multi-layer structure, so that the impact resistance and the flame-retardant property are realized, the insulating property of a pressure-sensitive adhesive tape product is also improved, and the 180-degree stripping force can reach 1800gf / inch; according to the utility model, the anti-impact performance of the product is improved through the silica gel pressure-sensitive adhesive layer; through the innovative structural design, the flame-retardant insulating pressure-sensitive adhesive tape for external protection of the power battery, which is better in impact-resistant flame-retardant effect and good in adhesive property, is prepared, is better applied to the field of external protection of the power battery and the field with higher requirements, and can be expanded to be applied to an energy storage battery cell.

Description

Technical Field

[0001] The utility model relates to the field of pressure-sensitive adhesive tapes, in particular to a flame-retardant insulating pressure-sensitive adhesive tape for external protection of a power battery. Background Art

[0002] The existing blue insulating protective film has poor flame retardant properties and even fails to meet the requirement of self-extinguishing when away from fire. This is determined by the characteristics of acrylic pressure-sensitive adhesive itself - the molecular chain mainly contains three elements: C, H, and O. Adding flame retardant ingredients to pressure-sensitive adhesive can improve the flame retardant properties of the product, but at the same time, the addition of flame retardants will affect the bonding properties of pressure-sensitive adhesives to a certain extent. Commonly used flame retardants can be divided into halogen flame retardants and inorganic flame retardants according to their ingredients. Due to environmental protection and safety requirements, the application of halogen flame retardants is limited. Inorganic flame retardants have attracted attention from all walks of life due to their green environmental protection and good flame retardant properties, but their poor compatibility with pressure-sensitive adhesives limits their application in pressure-sensitive adhesives.

[0003] Patent CN213895709U discloses a wear-resistant, flame-retardant, pressure-sensitive adhesive tape for protecting lithium battery shells. The utility model of the wear-resistant, flame-retardant, pressure-sensitive adhesive tape for protecting lithium battery shells includes a wear-resistant coating, a first PET substrate layer, a first primer coating, a first flame-retardant pressure-sensitive adhesive layer, a second PET substrate layer, a second primer coating, a second pressure-sensitive adhesive layer and a release layer arranged in sequence from top to bottom. It has high shear resistance, high bonding strength, and good rebound resistance for lithium battery shells, and has excellent wear resistance and flame retardant properties. It can be used for the bonding and protection of automotive lithium battery shells and other fields with higher requirements. However, the impact resistance, insulation and other properties that are of concern in the actual use scenarios of the power battery outer protective film have not been improved, so the use scenarios of the power battery outer protective film cannot be expanded.

[0004] Based on the above description, there is an urgent need for an impact-resistant and flame-retardant pressure-sensitive adhesive tape for the outer protective film of a power battery that has good impact resistance and flame retardancy and does not affect the bonding performance of the pressure-sensitive adhesive. Utility Model Content

[0005] The technical problem to be solved by the utility model is to provide a flame-retardant insulating pressure-sensitive adhesive tape for external protection of a power battery in view of the deficiencies in the above-mentioned prior art.

[0006] In order to solve the above technical problems, the technical solution adopted by the utility model is: a flame-retardant insulating pressure-sensitive tape for external protection of a power battery, comprising a first substrate layer, a first primer layer, a first adhesive layer, a second primer layer, a second substrate layer, a second adhesive layer and a release layer stacked in sequence; wherein the first adhesive layer is a silicone gel pressure-sensitive adhesive layer.

[0007] Preferably, the second adhesive layer is a flame retardant acrylic pressure-sensitive adhesive layer.

[0008] Preferably, the thickness of the first adhesive layer is ≥20 μm.

[0009] Preferably, the first adhesive layer has a storage modulus of 0.05 MPa-0.7 MPa, a loss factor of 0.08-0.6, and a peel force of ≥1000 gf / inch.

[0010] Preferably, the thickness of the second adhesive layer is ≥20 μm.

[0011] Preferably, the second adhesive layer has a storage modulus of 0.5 MPa-1.5 MPa, a loss factor of 0.3-0.8, and a peel force of ≥1500 gf / inch.

[0012] Preferably, the first substrate layer is a transparent PET base film with a thickness of 20 μm-100 μm.

[0013] Preferably, the second substrate layer is any one of a transparent PET base film, a flame retardant modified PET base film and a polyimide film, and has a thickness of 20 μm-100 μm.

[0014] Preferably, the first primer layer and the second primer layer are both acrylic resin layers or epoxy-modified acrylic resin layers, and have a thickness of 1-5 μm.

[0015] Preferably, the release layer is a release film or release paper with a thickness of 20 μm-50 μm and a release force of ≤50 gf / inch.

[0016] The beneficial effects of the utility model are:

[0017] The utility model provides a multi-layer structure of flame-retardant insulating pressure-sensitive adhesive tape for protecting the outer surface of a power battery, which achieves impact resistance and flame retardancy while improving the insulation performance of the pressure-sensitive adhesive tape product, and the 180° peeling force can reach 1800gf / inch;

[0018] The utility model improves the impact resistance of the product through the silicone gel pressure-sensitive adhesive layer;

[0019] The utility model uses innovative structural design to prepare a flame-retardant insulating pressure-sensitive adhesive tape for power battery outer protection with better impact resistance and flame retardancy and good bonding performance. The tape has good applications in the field of power battery outer protection and other fields with higher requirements, and can be expanded to energy storage cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic structural diagram of a flame-retardant insulating pressure-sensitive adhesive tape for outer protection of a power battery according to Example 1 of the utility model;

[0021] Figure 2 It is a structural schematic diagram of a flame-retardant insulating pressure-sensitive adhesive tape for outer protection of a power battery in a comparative example of the present utility model;

[0022] Description of reference numerals:

[0023] 1—first substrate layer; 2—first primer layer; 3—first adhesive layer; 4—second primer layer; 5—second substrate layer; 6—second adhesive layer; 7—release layer. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below in conjunction with embodiments so that those skilled in the art can implement the invention with reference to the description.

[0025] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0026] The utility model provides a flame-retardant insulating pressure-sensitive adhesive tape for protecting the outer surface of a power battery, which comprises a first substrate layer, a first primer layer, a first adhesive layer, a second primer layer, a second substrate layer, a second adhesive layer and a release layer which are stacked in sequence.

[0027] In a preferred embodiment, the first substrate layer is a transparent PET base film with a thickness of 20 μm-100 μm. The first substrate layer provides strength support and insulation protection for the product, plays the role of the first layer of buffer, and protects the adhesive layer.

[0028] In a preferred embodiment, the second substrate layer is any one of a transparent PET base film, a flame retardant modified PET base film and a polyimide film, with a thickness of 20 μm-100 μm. The second substrate layer provides strength support and insulation protection for the product, connects the first adhesive layer and the second adhesive layer, and provides a third layer of buffering.

[0029] In a preferred embodiment, if the thickness of the first substrate layer and the second substrate layer is less than 20 μm, they cannot provide effective strength support and electrical protection; if the thickness is selected to be greater than 100 μm, there will be a risk of hemming and warping due to excessive stiffness, so the thickness must be limited to 20 μm-100 μm.

[0030] In a preferred embodiment, the first adhesive layer is a silicone gel pressure-sensitive adhesive layer, the thickness of the first adhesive layer is ≥20 μm, the storage modulus is 0.05 MPa-0.7 MPa, the loss factor is 0.08-0.6, and the peel force is ≥1000 gf / inch. The first substrate layer and the second substrate layer are connected to provide a second layer of buffering, wherein the type of silicone gel pressure-sensitive adhesive is not limited, and any silicone gel pressure-sensitive adhesive that can achieve the above-mentioned performance is sufficient.

[0031] In a preferred embodiment, the second adhesive layer is a flame retardant acrylic pressure-sensitive adhesive layer, the thickness of the second adhesive layer is ≥20μm, the storage modulus is 0.5MPa-1.5MPa, the loss factor is 0.3-0.8, and the peel force is ≥1500gf / inch. Conventional organic phosphoric acid flame retardants are added to the flame retardant acrylic pressure-sensitive adhesive layer as a flame retardant component, and the choice of acrylic adhesive is not limited. Conventional acrylic adhesive products are used to make a layered structure with the above thickness and meeting the above performance parameter requirements. It should be understood that in the present utility model, no improvement is provided to the material of the flame retardant acrylic pressure-sensitive adhesive layer, and only conventional products that meet the above parameters are selected to make the flame retardant acrylic pressure-sensitive adhesive layer.

[0032] If the thickness of the first adhesive layer and the second adhesive layer is less than 20 μm, it cannot effectively meet the bonding requirements, so the thickness needs to be limited to greater than 20 μm. It should be understood that the present invention does not make any improvements to the materials of the first and second adhesive layers, and mainly provides an adhesive layer structure with the above-mentioned thickness, peeling force and other parameter requirements.

[0033] Among them, the peeling force of the first adhesive layer and the second adhesive layer increases successively, and the impact resistance decreases successively.

[0034] In a preferred embodiment, the first primer layer and the second primer layer are both acrylic resin layers or epoxy-modified acrylic resin layers with a thickness of 1-5 μm; they can activate the surface of the silicone layer, improve the adhesion between the silicone gel pressure-sensitive adhesive layer and the first substrate layer and the second substrate layer, and avoid interlayer tearing between the first substrate layer and the second substrate layer. It should be understood that the present invention does not make any improvements to acrylic resin and epoxy-modified acrylic resin, and all commonly used known materials in the art are selected.

[0035] In a preferred embodiment, the release layer is a release film or a release paper with a thickness of 20 μm-50 μm and a release force of ≤50 gf / inch.

[0036] The above is the overall concept of the present invention, and detailed embodiments and comparative examples are provided below on the basis of the overall concept to further illustrate the present invention.

[0037] In the following embodiments, the preparation process of the flame-retardant insulating pressure-sensitive adhesive tape for external protection of power batteries is as follows:

[0038] S1. After corona treatment of the second substrate layer, a flame retardant pressure sensitive adhesive is coated on the corona surface (upper surface) to form a second adhesive layer, and the adhesive surface (lower surface) is attached to the release layer;

[0039] S2, coating the non-corona surface of the second substrate layer with a second primer to form a second primer layer;

[0040] S3. After corona treatment of the first substrate layer, a first primer is coated on the corona surface to form a first primer layer, a silicone gel pressure-sensitive adhesive is coated on the bottom surface of the first primer layer to form a first bonding layer, and then the adhesive surface of the silicone gel pressure-sensitive adhesive is attached to the second primer layer on the second substrate surface to finally obtain a flame-retardant insulating pressure-sensitive adhesive tape for external protection of a power battery.

[0041] The preparation process of the flame-retardant insulating pressure-sensitive adhesive tape for outer protection of power batteries in the following comparative examples is similar and will not be described in detail.

[0042] The silicone gel pressure-sensitive adhesive is prepared according to the silicone gel, preparation method and protective film using the silicone gel in patent CN114316896B;

[0043] The flame retardant pressure sensitive adhesive is specifically an acrylic adhesive (model A-533 Guangzhou Panyu Runyi Chemical) to which a flame retardant component (organic phosphate, model 1001A Aidico Fine Chemical) is added;

[0044] The epoxy-modified acrylic resin used to prepare the first primer layer and the second primer layer is specifically: Dow Corning R300F.

[0045] The difference between the comparative example and the embodiment is that the structure and type of the substrate layer are different. The preparation process is basically the same as that of the embodiment, which is only adjusted accordingly according to the different structure and type of the substrate layer, and will not be repeated below.

[0046] It should be understood that the above-mentioned preparation process is only based on the conventional process for obtaining the flame-retardant insulating pressure-sensitive adhesive tape for outer protection of power batteries of the structure shown in the comparative examples and the embodiments. It is displayed to facilitate the understanding of the present invention, but the present invention does not make any improvements or restrictions on its preparation process. As long as the flame-retardant insulating pressure-sensitive adhesive tape product with the above-mentioned structure can be obtained, the purpose of the present invention is to provide a flame-retardant insulating pressure-sensitive adhesive tape for outer protection of power batteries with the above structure.

[0047] Example 1

[0048] Reference Figure 1 The present embodiment provides a flame-retardant insulating pressure-sensitive adhesive tape for external protection of a power battery, comprising a first substrate layer 1, a first primer layer 2, a first adhesive layer 3, a second primer layer 4, a second substrate layer 5, a second adhesive layer 6 and a release layer 7 stacked in sequence from top to bottom.

[0049] Among them, the first substrate layer 1 and the second substrate layer 5 are both 0.025mm thick PET layers; the thickness of the first primer layer 2 and the second primer layer 4 are both 1μm; the first adhesive layer 3 is a 0.03mm thick flame-retardant silicone acrylic adhesive layer, and the second adhesive layer 6 is a 0.03mm thick flame-retardant acrylic adhesive layer, wherein the first adhesive layer 3 is a colored adhesive layer, the color is not limited, and it mainly provides aesthetics, and the release layer 7 is a release film with a thickness of 25μm.

[0050] Comparative Example 1

[0051] Reference Figure 2 This example is basically the same as Example 1, with the only difference being that the middle portion of this example includes a first primer layer and a second primer layer, that is, the power battery external protection flame-retardant insulating pressure-sensitive adhesive tape provided in this example includes a first substrate layer 1, a first adhesive layer 2, a second substrate layer 3, a second adhesive layer 4 and a release layer 5 stacked in sequence from top to bottom.

[0052] Comparative Example 2

[0053] The flame-retardant insulating pressure-sensitive adhesive tape for protecting the power battery provided in this example includes a first substrate layer 1, a first adhesive layer 2, a second substrate layer 3, a second adhesive layer 4 and a release layer 5 which are sequentially stacked from top to bottom. Figure 2 .

[0054] Among them, the first substrate layer 1 and the second substrate layer 3 are both 0.025mm thick PET layers, the first adhesive layer 2 and the second adhesive layer 4 are both 0.03mm thick silicone gel acrylic pressure-sensitive adhesive layers, among which the first adhesive layer 2 is a colored adhesive layer with no color limitation, mainly providing aesthetics, and the release layer 5 is a release film with a thickness of 25μm.

[0055] Comparative Example 3

[0056] The flame-retardant insulating pressure-sensitive adhesive tape for protecting the power battery provided in this example includes a first substrate layer 1, a first adhesive layer 2, a second substrate layer 3, a second adhesive layer 4 and a release layer 5 which are sequentially stacked from top to bottom. Figure 2 .

[0057] Among them, the first substrate layer 1 and the second substrate layer 3 are both 0.025mm thick PET layers, the first bonding layer 2 is a 0.03mm thick silicone gel acrylic pressure-sensitive adhesive layer, and the second bonding layer 4 is a 0.03mm thick ordinary acrylic pressure-sensitive adhesive layer (the acrylic adhesive model is A-533, the company is Guangzhou Panyu Runyi Chemical, and no flame retardant ingredients are added). The first bonding layer 2 is a colored adhesive layer with no color limitation, which mainly provides aesthetics. The release layer 5 is a release film with a thickness of 25μm.

[0058] Comparative Example 4

[0059] The flame-retardant insulating pressure-sensitive adhesive tape for protecting the power battery provided in this example includes a first substrate layer 1, a first adhesive layer 2, a second substrate layer 3, a second adhesive layer 4 and a release layer 5 which are sequentially stacked from top to bottom. Figure 2 .

[0060] The first substrate layer 1 and the second substrate layer 3 are both 0.025 mm thick PET layers, the first adhesive layer 2 and the second adhesive layer 4 are both 0.03 mm thick flame-retardant acrylic pressure-sensitive adhesive layers, and the release layer 5 is a release film with a thickness of 25 μm.

[0061] Comparative Example 5

[0062] The flame-retardant insulating pressure-sensitive adhesive tape for protecting the power battery provided in this example includes a first substrate layer 1, a first adhesive layer 2, a second substrate layer 3, a second adhesive layer 4 and a release layer 5 which are sequentially stacked from top to bottom. Figure 2 .

[0063] Among them, the first substrate layer 1 and the second substrate layer 3 are both 0.025 mm thick PET layers, the first bonding layer 2 is a 0.03 mm thick ordinary acrylic pressure-sensitive adhesive layer (the acrylic adhesive model is A-533, Guangzhou Panyu Runyi Chemical, without adding flame retardant ingredients), the second bonding layer 4 is a 0.03 mm thick flame-retardant acrylic pressure-sensitive adhesive layer, and the release layer 5 is a release film with a thickness of 25 μm.

[0064] Comparative Example 6

[0065] The flame-retardant insulating pressure-sensitive adhesive tape for protecting the power battery provided in this example includes a first substrate layer 1, a first adhesive layer 2, a second substrate layer 3, a second adhesive layer 4 and a release layer 5 which are sequentially stacked from top to bottom. Figure 2 .

[0066] Among them, the first substrate layer 1 and the second substrate layer 3 are both 0.025 mm thick PET layers, the first adhesive layer 2 and the second adhesive layer 4 are both 0.03 mm thick ordinary acrylic pressure-sensitive adhesive layers (acrylic adhesive model is A-533, Guangzhou Panyu Runyi Chemical, no flame retardant ingredients are added), and the release layer 5 is a release film with a thickness of 25 μm.

[0067] The double-layer composite flame-retardant insulating pressure-sensitive adhesive tapes prepared in Example 1 and Comparative Examples 1-5 were subjected to relevant performance tests, and the test results are shown in Table 1 below:

[0068] Table 1

[0069]

[0070] Among them, the 180° peel strength test standard is: GB / T 2792-2014 Adhesive tape peel strength test;

[0071] Flame retardant grade standard: GB / T2048-2021 Determination of combustion performance of plastics;

[0072] 3000VAC leakage current test standard: refer to GB / T 1408.1-2016 Insulation material electrical strength test method Part 1 Power frequency test, test 5 samples and take the average value. Apply 3000V alternating current (AC) to both ends of the electrode, and record the maximum current value passing through the sample in 60s. This value is the leakage current;

[0073] The 1000V DC insulation resistance test method is as follows: the electrodes are metal strip clips with a size of 10(±0.5)mm*10(±0.5)mm*50±0.5mm, and the distance between the two electrodes is 25±0.5mm. Load DC1000V for 60s, record the steady-state current, and the ratio of voltage to current is the insulation resistance.

[0074] Drop test method: stick the pressure-sensitive adhesive to the surface of the outer aluminum shell of the power battery and place it flat on the test bench. Place a 150g steel ball directly above the sample to test the free fall motion at a height of 25cm, and then observe whether there is any abnormality in the appearance of the pressure-sensitive adhesive tape sample and the aluminum shell.

[0075] By comparing the results between the embodiment and comparative example 1, it can be seen that the addition of the primer can effectively improve the interlayer adhesion; by comparing the results between embodiment 1 and comparative examples 1, 2, 4, and 5, it can be seen that when the second adhesive layer is the same and the first adhesive layer is silicone gel, its impact resistance is the best, and the bonding performance has not decreased, playing a more active role in the impact protection of the external power battery; by comparing the results between embodiment 1 and comparative examples 2, 3, and 6, it can be seen that when the first adhesive layer is the same, the flame retardant effect of the product is mainly provided by the second adhesive layer; by comparative example 2, it can be seen that the first adhesive layer can also provide a certain flame retardant effect. Based on the above comparison, this embodiment 1 has obtained better indicators both in terms of impact protection performance and flame retardant performance, and can be effectively used in the field of external protection of power batteries and fields with higher requirements.

[0076] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0077] Although the implementation scheme of the utility model has been disclosed as above, it is not limited to the applications listed in the specification and implementation scheme. It can be fully applied to various fields suitable for the utility model. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the utility model is not limited to specific details.

Claims

1. A flame-retardant insulating pressure-sensitive adhesive tape for external protection of a power battery, characterized in that: The invention comprises a first substrate layer, a first primer layer, a first adhesive layer, a second primer layer, a second substrate layer, a second adhesive layer and a release layer which are sequentially stacked; wherein the first adhesive layer is a silicone gel pressure-sensitive adhesive layer; The second adhesive layer is a flame retardant acrylic pressure sensitive adhesive layer; The storage modulus of the second adhesive layer is 0.5MPa-1.5MPa, the loss factor is 0.3-0.8, and the peel force is ≥1500gf / inch; The first substrate layer is a transparent PET base film with a thickness of 20 μm-100 μm; The second substrate layer is any one of a transparent PET base film, a flame retardant modified PET base film and a polyimide film, and has a thickness of 20 μm-100 μm.

2. The flame-retardant insulating pressure-sensitive adhesive tape for outer protection of power batteries according to claim 1, characterized in that: The thickness of the first adhesive layer is ≥20 μm.

3. The flame-retardant insulating pressure-sensitive adhesive tape for outer protection of power batteries according to claim 2, characterized in that: The first adhesive layer has a storage modulus of 0.05 MPa-0.7 MPa, a loss factor of 0.08-0.6, and a peel force of ≥1000 gf / inch.

4. The flame-retardant insulating pressure-sensitive adhesive tape for outer protection of power batteries according to claim 1, characterized in that: The thickness of the second adhesive layer is ≥20 μm.

5. The flame-retardant insulating pressure-sensitive adhesive tape for outer protection of power batteries according to claim 1, characterized in that: The first primer layer and the second primer layer are both acrylic resin layers or epoxy-modified acrylic resin layers, and have a thickness of 1-5 μm.

6. The flame-retardant insulating pressure-sensitive adhesive tape for outer protection of power batteries according to claim 1, characterized in that: The release layer is a release film or release paper with a thickness of 20 μm-50 μm and a release force of ≤50 gf / inch.

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