Blue adhesive tape

Abstract

The utility model discloses a blue adhesive tape, which is used for binding and packaging batteries of new energy electric vehicles and comprises a surface PET (polyethylene terephthalate) transparent film (1), a middle blue adhesive layer (2), a bottom PET transparent film (3) and a back blue adhesive layer (4). In order to protect the back blue adhesive layer (4), a PET release film (5) can be attached to the outer side of the back blue adhesive layer (4). The blue adhesive tape provided by the utility model is excellent in dielectric strength, flexibility, puncture resistance and flame retardance, the characteristics directly correspond to strict requirements of packaging of the automobile lithium battery shell, and comprehensive guarantee is provided for safety, reliability and environmental adaptability.

Description

TECHNICAL FIELD

[0001] The utility model relates to the bundling and packing tape of new energy electric vehicle battery, especially a kind of blue tape. BACKGROUND

[0002] The battery of new energy electric vehicle is usually bound and packed using blue film tape, and the blue tape is also called blue film tape or PET blue film, which is a single-sided tape with pressure-sensitive adhesive on PET substrate, and is named for its dark blue appearance. It is mainly used for insulation protection and fixation of power battery, and is widely used in lithium battery packaging in the fields of electric vehicles, mobile phones, notebook computers and the like.

[0003] In the packaging and assembly process of new energy electric vehicle battery, the blue film tape needs to cope with the risk of thermal runaway, for example, internal short circuit or external short circuit of battery can cause thermal runaway, which can cause the risk of fire or explosion. It also needs to cope with the risk of electric shock, for example, if the conductive part of the battery is exposed without proper covering or protection, it can cause electric shock to the operator. The existing blue tape usually has the problems of insufficient adhesion, insufficient tensile property and tensile strength, poor insulation performance and insufficient tear resistance. SUMMARY

[0004] The technical problem to be solved by the utility model is to provide a blue tape to reduce or avoid the problems mentioned above.

[0005] To solve the above technical problems, the utility model provides a blue tape for bundling and packing the battery of new energy electric vehicle, wherein the blue tape is composed of a surface layer PET transparent film, a middle blue adhesive layer, a bottom layer PET transparent film and a back blue adhesive layer.

[0006] Preferably, the outer side of the back blue adhesive layer is attached with a layer of PET release film.

[0007] Preferably, the thickness of the surface layer PET transparent film is 50-85 μm.

[0008] Preferably, the thickness of the bottom layer PET transparent film is 50-85 μm.

[0009] Preferably, the thickness of the blue tape is 185-275 μm.

[0010] The blue tape designed by the utility model performs outstandingly in dielectric strength, flexibility, puncture resistance and flame retardance, which directly meets the strict requirements of automobile lithium battery shell packaging and provides comprehensive guarantee for safety, reliability and environmental adaptability. BRIEF DESCRIPTION OF DRAWINGS

[0011] The accompanying drawings are intended only to illustrate and explain this application and do not limit the scope of this utility model.

[0012] Figure 1 The diagram shown is a structural schematic of a blue tape according to a specific embodiment of the present invention. Detailed Implementation

[0013] To provide a clearer understanding of the technical features, objectives, and effects of this utility model, specific embodiments are now described with reference to the accompanying drawings. Identical components are denoted by the same reference numerals.

[0014] like Figure 1 As shown, this utility model proposes a blue adhesive tape for bundling and packaging batteries of new energy electric vehicles. The blue adhesive tape consists of a surface PET transparent film 1, a middle blue adhesive layer 2, a bottom PET transparent film 3, and a back blue adhesive layer 4. To protect the back blue adhesive layer 4, a PET release film 5 can be attached to the outside of the back blue adhesive layer 4. When bundling and packaging the battery, the PET release film 5 needs to be removed, and the battery is then bonded and wrapped using the back blue adhesive layer 4.

[0015] Unlike traditional blue tape which uses a single-layer PET film, this invention uses an intermediate blue adhesive layer 2 to bond the top PET transparent film 1 and the bottom PET transparent film 3 together to form a sandwich film. This sandwich film replaces the traditional single-layer PET film to obtain excellent shear resistance, abrasion resistance and puncture resistance. Moreover, compared with the single-layer PET film, the sandwich film has better tensile strength, softness and conformability.

[0016] Furthermore, this utility model designs and proposes a polyester film for blue adhesive tape, that is, a specially made transparent PET film, which can be used to bond two layers of polyester film into a sandwich film by means of blue adhesive, so that the sandwich film has the above-mentioned excellent properties.

[0017] Specifically, the polyester film for blue adhesive tape of this invention is composed of 70-85 parts by weight of high-viscosity polyethylene terephthalate (PET), 5-12 parts by weight of thermoplastic polyurethane (TPU), 2-4 parts by weight of siloxane resin powder, 1-3 parts by weight of melamine cyanurate (MCA), 2-5 parts by weight of organically modified montmorillonite, 1-3 parts by weight of aromatic polyimide (PI) micro powder, and 0.3-0.5 parts by weight of ethylene glycol monostearate (EGMS).

[0018] Furthermore, high-viscosity polyethylene terephthalate (PET) is used as the matrix material to provide excellent mechanical properties, heat resistance and dimensional stability, with PET having an intrinsic viscosity ≥0.8 being preferred.

[0019] Thermoplastic polyurethane (TPU) is used to improve the flexibility and conformability of the film, reduce the overall brittleness; at the same time, through the blending with the PET matrix, the softness and conformability of the film are significantly improved. Desmopan series TPU of Bayer, Germany, for example, can be selected.

[0020] Silicone resin powder is used as a synergistic flame retardant to improve the flame retardant performance, form a dense silicon oxide layer on the surface to prevent the spread of combustion; at the same time, it is used to enhance the wear resistance and smoothness of the material surface. Dow Corning 904H of Dow Corning Company can be selected.

[0021] Melamine cyanurate (MCA) is used to provide efficient nitrogen-based flame retardant function, release inert gas at high temperature, and inhibit combustion. Conventional MCA on the market can be used.

[0022] Organically modified montmorillonite provides a layered reinforcing effect, which is used to enhance the puncture resistance and mechanical strength of the film, and at the same time, improve the barrier properties and adhesion. At the same time, due to its nanosheet structure, the barrier property and wear resistance are enhanced, and the adhesion of the blue adhesive can be improved. Cloisite 30B of Clariant Company, Switzerland, can be selected.

[0023] Aromatic polyimide (PI) powder is used to improve the electrical insulation performance (dielectric strength and volume resistance) of the material, enhance the puncture resistance and heat deformation resistance, and is particularly suitable for the high-strength protection requirements of automobile lithium batteries. The PI powder forms a micro-dispersed phase in the film, which can also enhance the overall mechanical properties. PI powder with a particle size of 1-5 μm, such as Kapton polyimide powder series of DuPont, can be selected.

[0024] Ethylene glycol monostearate (EGMS) is used to provide excellent dispersion effect while maintaining the overall mechanical properties and thermal stability of the material. Conventional EGMS on the market can be used.

[0025] In one embodiment, the polyester film for the blue adhesive tape of the present application can be prepared by the following method.

[0026] For example, before starting to prepare the polyester film, the raw materials are first pretreated to ensure the uniformity and compatibility of the components.

[0027] For example, high viscosity PET (intrinsic viscosity > 0.8) needs to be preheated to 80-100°C to reduce its viscosity and improve its flowability. Thermoplastic polyurethane (TPU) needs to be preheated to 50-70°C to prevent caking and ensure its good mixing with the polyester matrix. Silicone resin powder (such as Dow Corning 904H) needs to be sieved through a mesh smaller than 100 to ensure the uniformity of the powder and avoid agglomeration. Melamine cyanurate (MCA), aromatic polyimide (PI) micro powder, and ethylene glycol monostearate (EGMS) can all be directly added without pretreatment.

[0028] In order to avoid agglomeration, the organic modified montmorillonite needs to be subjected to ultrasonic dispersion treatment. For example, the organic modified montmorillonite (such as Cloisite 30B) can be mixed with isopropyl alcohol in a weight ratio of 1:0.5-1:2, and then subjected to ultrasonic dispersion treatment at a frequency of 20-40 kHz for 30-60 minutes to ensure its uniform dispersion. Isopropyl alcohol has high volatility (boiling point 82.5°C) and will quickly evaporate before the melt extrusion of the polyester material or during the cooling process, leaving no residue in the film.

[0029] After the pretreatment of the raw materials, all the raw materials are added to the twin-screw extruder according to the ratio for high-shear melt blending, wherein the high-shear mixing parameters of the twin-screw extruder are set as follows: screw rotation speed 250-500 rpm, shear rate 100-500 s -1 , residence time of the material in the mixing zone 60-90 seconds. The order of addition of the components is as follows: first add the PET matrix, then add the TPU and other additives to ensure good mixing effect.

[0030] During the twin-screw extrusion process, high shear can form a microscopically uniform dispersion system of PET, TPU, and montmorillonite. High shear conditions can strip the layered structure of montmorillonite, increase the interfacial interaction, and at the same time improve the dispersibility and uniformity of the material. At the same time, high shear can enhance the micro network structure, so that the mechanical strength and flexibility of the film are simultaneously improved.

[0031] After the melt blending of the raw materials, the material is extruded through the twin-screw extruder, with the extrusion temperature set to 250-280°C. After extrusion, bidirectional stretching is performed: first longitudinal stretching with a stretching ratio of 2-4 times, and then transverse stretching with a stretching ratio of 3.5 times. During the stretching process, the temperature is controlled between 150-180°C to ensure that the film can be effectively stretched and maintain excellent physical properties.

[0032] After bidirectional stretching, the film is cooled by a cooling system at a cooling temperature of 30-50°C to ensure rapid solidification of the film. Finally, the cooled film is wound by an automatic winding machine, and the winding speed is usually 5-15 m / min.

[0033] The functional properties of the polyester film for blue adhesive tape of the present application will be described in detail below through specific examples.

[0034] Example 1

[0035] High viscosity polyethylene terephthalate: 70 parts by weight; thermoplastic polyurethane: 5 parts by weight; silicone resin powder: 2 parts by weight; melamine cyanurate: 1 part by weight; organically modified montmorillonite: 2 parts by weight; aromatic polyimide micro powder: 1 part by weight; fatty acid ester dispersant: 0.3 parts by weight.

[0036] The polyester film obtained in the preparation has a thickness of 50 μm. The various performance parameters of the film are measured as follows: dielectric strength: 130 kV / mm; volume resistance: ≥ 10 14 Ω·cm; tensile strength: 162 MPa; elongation at break: 115%; puncture resistance: 85 N / mm; flame retardancy (UL-94): V-0; adhesion (to adhesive): ≥ 30 N / 25 mm.

[0037] Example 2

[0038] High viscosity polyethylene terephthalate: 85 parts by weight; thermoplastic polyurethane: 12 parts by weight; silicone resin powder: 4 parts by weight; melamine cyanurate: 3 parts by weight; organically modified montmorillonite: 5 parts by weight; aromatic polyimide micro powder: 3 parts by weight; fatty acid ester dispersant: 0.5 parts by weight.

[0039] The polyester film obtained in the preparation has a thickness of 60 μm. The various performance parameters of the film are measured as follows: dielectric strength: 135 kV / mm; volume resistance: ≥ 10 14 Ω·cm; tensile strength: 170 MPa; elongation at break: 120%; puncture resistance: 90 N / mm; flame retardancy (UL-94): V-0; adhesion (to adhesive): ≥ 32 N / 25 mm.

[0040] Example 3

[0041] High viscosity polyethylene terephthalate: 77.5 parts by weight; thermoplastic polyurethane: 8.5 parts by weight; silicone resin powder: 3 parts by weight; melamine cyanurate: 2 parts by weight; organically modified montmorillonite: 3.5 parts by weight; aromatic polyimide micro powder: 2 parts by weight; fatty acid ester dispersant: 0.4 parts by weight.

[0042] The polyester film obtained in the preparation has a thickness of 75 μm. The various performance parameters of the film are measured as follows: dielectric strength: 125 kV / mm; volume resistance: ≥ 10 14Ω-cm; tensile strength: 165 MPa; elongation at break: 118%; puncture resistance: 87 N / mm; flame retardancy (UL-94): V-0; adhesion (to adhesive): > 31 N / 25 mm.

[0043] Example 4

[0044] High viscosity polyethylene terephthalate: 80 parts by weight; thermoplastic polyurethane: 7 parts by weight; silicone resin powder: 3.5 parts by weight; melamine cyanurate: 2.5 parts by weight; organically modified montmorillonite: 4 parts by weight; aromatic polyimide micro powder: 2.5 parts by weight; fatty acid ester dispersant: 0.4 parts by weight.

[0045] The polyester film obtained by the preparation had a thickness of 85 μm. The various performance parameters of the film were measured as follows: dielectric strength: 140 kV / mm; volume resistance: > 10 14 Ω-cm; tensile strength: 167 MPa; elongation at break: 122%; puncture resistance: 92 N / mm; flame retardancy (UL-94): V-0; adhesion (to adhesive): > 33 N / 25 mm.

[0046] Example 5

[0047] High viscosity polyethylene terephthalate: 75 parts by weight; thermoplastic polyurethane: 10 parts by weight; silicone resin powder: 3 parts by weight; melamine cyanurate: 2 parts by weight; organically modified montmorillonite: 4.5 parts by weight; aromatic polyimide micro powder: 2 parts by weight; fatty acid ester dispersant: 0.3 parts by weight.

[0048] The polyester film obtained by the preparation had a thickness of 65 μm. The various performance parameters of the film were measured as follows: dielectric strength: 132 kV / mm; volume resistance: > 10 14 Ω-cm; tensile strength: 162 MPa; elongation at break: 116%; puncture resistance: 88 N / mm; flame retardancy (UL-94): V-0; adhesion (to adhesive): > 32 N / 25 mm.

[0049] Example 6

[0050] High viscosity polyethylene terephthalate: 78 parts by weight; thermoplastic polyurethane: 9 parts by weight; silicone resin powder: 3 parts by weight; melamine cyanurate: 2 parts by weight; organically modified montmorillonite: 4 parts by weight; aromatic polyimide micro powder: 2 parts by weight; fatty acid ester dispersant: 0.4 parts by weight.

[0051] The polyester film obtained by the preparation had a thickness of 70 μm. The various performance parameters of the film were measured as follows: dielectric strength: 128 kV / mm; volume resistance: > 10 14Ω-cm; tensile strength: 160 MPa; elongation at break: 114%; puncture resistance: 85 N / mm; flame retardancy (UL-94): V-0; adhesion (to adhesive): > 30 N / 25 mm.

[0052] The performance parameters of the polyester film of Example 1-6 are summarized as follows: dielectric strength > 120 kV / mm; volume resistance > 10 14 Ω-cm; tensile strength > 160 MPa; elongation at break > 110%; puncture resistance > 80 N / mm; flame retardancy UL94 V-0; adhesion (to adhesive) > 30 N / 25 mm.

[0053] Comparative Example 1

[0054] The aromatic polyimide was replaced with a general polyimide, and the film thickness was 50 μm.

[0055] High viscosity polyethylene terephthalate: 70 parts by weight; thermoplastic polyurethane: 5 parts by weight; silicone resin powder: 2 parts by weight; melamine cyanurate: 1 part by weight; organically modified montmorillonite: 2 parts by weight; general polyimide (instead of aromatic polyimide micro powder): 3 parts by weight; fatty acid ester dispersant: 0.3 parts by weight.

[0056] The performance parameters are summarized as follows: dielectric strength: 115 kV / mm; volume resistance: > 10 13 Ω-cm; tensile strength: 150 MPa; elongation at break: 100%; puncture resistance: 60 N / mm; flame retardancy (UL-94): V-1; adhesion (to adhesive): > 25 N / 25 mm.

[0057] Analysis: The use of a general polyimide instead of an aromatic polyimide will greatly reduce the heat resistance, rigidity, and dielectric properties of the film, resulting in a significant decrease in dielectric strength and puncture resistance.

[0058] Comparative Example 2

[0059] The content of thermoplastic polyurethane was reduced, and the film thickness was 55 μm.

[0060] High viscosity polyethylene terephthalate: 80 parts by weight; thermoplastic polyurethane: 3 parts by weight; silicone resin powder: 2 parts by weight; melamine cyanurate: 2 parts by weight; organically modified montmorillonite: 4 parts by weight; aromatic polyimide micro powder: 2 parts by weight; fatty acid ester dispersant: 0.4 parts by weight.

[0061] The performance parameters are summarized as follows: dielectric strength: 125 kV / mm; volume resistance: > 10 13Ω-cm; tensile strength: 158 MPa; elongation at break: 105%; puncture resistance: 70 N / mm; flame retardancy (UL-94): V-2; adhesion (to adhesive): > 28 N / 25 mm.

[0062] Analysis: Reducing the content of thermoplastic polyurethane will result in a decrease in the softness and conformability of the film, thereby affecting the tensile strength and puncture resistance.

[0063] Comparative Example 3

[0064] Silicone resin powder was not used, and the film thickness was 60 μm.

[0065] High viscosity polyethylene terephthalate: 75 parts by weight; thermoplastic polyurethane: 8 parts by weight; melamine cyanurate: 2 parts by weight; organically modified montmorillonite: 3 parts by weight; aromatic polyimide micro powder: 2 parts by weight; fatty acid ester dispersant: 0.4 parts by weight.

[0066] Performance parameters: dielectric strength: 125 kV / mm; volume resistance: > 10 13 Ω-cm; tensile strength: 160 MPa; elongation at break: 110%; puncture resistance: 65 N / mm; flame retardancy (UL-94): V-1; adhesion (to adhesive): > 26 N / 25 mm.

[0067] Analysis: Not using silicone resin will reduce the wear resistance and flame retardancy of the film, resulting in a decrease in the flame retardancy and puncture resistance of the film.

[0068] Comparative Example 4

[0069] Melamine cyanurate was omitted, and the film thickness was 65 μm.

[0070] High viscosity polyethylene terephthalate: 80 parts by weight; thermoplastic polyurethane: 7 parts by weight; silicone resin powder: 3 parts by weight; organically modified montmorillonite: 4 parts by weight; aromatic polyimide micro powder: 2.5 parts by weight; fatty acid ester dispersant: 0.4 parts by weight.

[0071] Performance parameters: dielectric strength: 125 kV / mm; volume resistance: > 10 13 Ω-cm; tensile strength: 165 MPa; elongation at break: 100%; puncture resistance: 60 N / mm; flame retardancy (UL-94): V-2; adhesion (to adhesive): > 25 N / 25 mm.

[0072] Analysis: Removing melamine cyanurate resulted in a significant decrease in the flame retardancy of the film, and the puncture resistance became poor.

[0073] Comparative Example 5

[0074] Without using organic modified montmorillonite, film thickness 70 μm.

[0075] High viscosity polyethylene terephthalate: 80 parts by weight; thermoplastic polyurethane: 9 parts by weight; silicone resin powder: 3 parts by weight; melamine cyanurate: 2 parts by weight; aromatic polyimide micro powder: 3 parts by weight; fatty acid ester dispersant: 0.5 parts by weight.

[0076] Performance parameters: dielectric strength: 118 kV / mm; volume resistance: ≥ 10 12 Ω·cm; tensile strength: 155 MPa; elongation at break: 90%; puncture resistance: 55 N / mm; flame retardancy (UL-94): V-2; adhesion (to adhesive): ≥ 22 N / 25 mm.

[0077] Analysis: Without using organic modified montmorillonite, the comprehensive properties of the film, such as puncture resistance, tensile strength, and adhesion, are reduced.

[0078] Comparative Example 6

[0079] Without using fatty acid ester, film thickness 75 μm.

[0080] High viscosity polyethylene terephthalate: 77.5 parts by weight; thermoplastic polyurethane: 8.5 parts by weight; silicone resin powder: 3 parts by weight; melamine cyanurate: 2 parts by weight; organic modified montmorillonite: 4 parts by weight; aromatic polyimide micro powder: 2 parts by weight.

[0081] Performance parameters: dielectric strength: 120 kV / mm; volume resistance: ≥ 10 13 Ω·cm; tensile strength: 160 MPa; elongation at break: 105%; puncture resistance: 60 N / mm; flame retardancy (UL-94): V-2; adhesion (to adhesive): ≥ 24 N / 25 mm.

[0082] Analysis: After removing the fatty acid ester dispersant, the dispersibility is poor, and the flexibility and adhesion of the film are reduced.

[0083] Comparative Example 7

[0084] Without using high shear conditions, film thickness 80 μm.

[0085] High viscosity polyethylene terephthalate: 75 parts by weight; thermoplastic polyurethane: 8 parts by weight; silicone resin powder: 2 parts by weight; melamine cyanurate: 1.5 parts by weight; organic modified montmorillonite: 3 parts by weight; aromatic polyimide micro powder: 2 parts by weight; ethylene glycol monostearate: 0.4 parts by weight.

[0086] Process characteristics: hot-melt mixing using a twin-screw extruder, setting the usual mixing parameters, without using high-shear conditions. The temperature range is controlled between 200 and 230°C, in order to ensure the complete melting of the polymers, but avoiding excessive shearing forces.

[0087] Performance parameters: dielectric strength: 118 kV / mm; volume resistance: > 10 13 Ω-cm; tensile strength: 155 MPa; elongation at break: 95%; puncture resistance: 60 N / mm; flame retardancy (UL-94): V-l; adhesion (to adhesives): > 22 N / 25 mm.

[0088] Analysis: without using high-shear conditions, the dispersion of the materials is relatively poor, especially as regards the dispersion of the montmorillonite and the silicone resin powder. This leads to a decrease in some of the properties of the film (such as tensile strength, puncture resistance and flame retardancy), especially as regards flexibility and adhesion. Of course, despite the absence of high-shear conditions, a good hot-melt mixing effect is still obtained, thanks to the appropriate temperature control, ensuring that the main properties of the polymer matrix are stable.

[0089] Comparative example 8

[0090] The intrinsic viscosity of the polyethylene terephthalate was reduced to the usual value, and the film thickness was 85 μm.

[0091] Polyethylene terephthalate (IV = 0.6): 75 parts by weight; thermoplastic polyurethane: 8 parts by weight; silicone resin powder: 2 parts by weight; melamine cyanurate: 1 part by weight; organically modified montmorillonite: 3 parts by weight; aromatic polyimide micro powder: 2 parts by weight; ethylene glycol monostearate: 0.4 parts by weight.

[0092] Performance parameters: dielectric strength: 110 kV / mm; volume resistance: > 10 12 Ω-cm; tensile strength: 140 MPa; elongation at break: 90%; puncture resistance: 50 N / mm; flame retardancy (UL-94): V-2; adhesion (to adhesives): > 20 N / 25 mm.

[0093] Analysis: The molecular chain of low viscosity polyethylene terephthalate is short, which leads to the decrease of tensile strength and rigidity of the film. The film will show poor puncture resistance and adhesion. The molecular chain of polyester with low viscosity is not as long as that of polyester with high viscosity, so the flowability in the molten state is increased, which can lead to the decrease of elongation at break of the film, and has a negative impact on the mechanical strength and puncture resistance of the film. The key properties such as dielectric strength, tensile strength and puncture resistance will decrease, because the polyester matrix with short molecular chain is not as tough as the polyester with high viscosity, which cannot provide sufficient mechanical strength and insulation. The flame retardant performance is reduced, because the polyester molecular chain structure with low viscosity has poor bearing capacity for melamine cyanurate, which leads to poor flame retardant performance (UL94 V-2).

[0094] The polyester films prepared by Examples 1-6 are used to prepare adhesive tapes 1-6, respectively. The basic parameters of the adhesive tapes 1-6 are as follows: surface layer PET transparent film 1: polyester film of Examples 1-6, thicknesses are 50, 60, 75, 85, 65 and 70 μm, respectively. Middle blue adhesive layer 2: conventional acrylic pressure-sensitive adhesive, adding blue pigment, thickness 20 μm. Bottom layer PET transparent film 3: the same polyester film as surface layer 1, thicknesses are 50, 60, 75, 85, 65 and 70 μm, respectively. Back blue adhesive layer 4: also acrylic pressure-sensitive adhesive, thickness 15 μm. Release film 5: conventional PET release film, thickness 50 μm, coated with silicone release layer.

[0095] The performance parameters of the six adhesive tapes are shown in the following table.

[0096]

[0097]

[0098] The conventional PET adhesive tape with the following parameters is used to compare the performance improvement ratio of the adhesive tapes 1-6 of the present application relative to the conventional PET adhesive tape. The performance parameters of the conventional PET adhesive tape are: dielectric strength 100 kV / mm; tensile strength 120 MPa; elongation at break 80%; puncture resistance 50 N / mm; adhesion 20 N / 25 mm; flame retardant grade (UL-94) V-2.

[0099]

[0100] By comparison, the blue adhesive tape of the utility model can be found to have a significant improvement in key performance. For example, the dielectric strength is significantly improved by 10%-30%, thanks to the high dielectric properties and uniformity of the polyester film. The tensile strength is improved by 25%-37.5%, thanks to the high viscosity polyester and filler reinforcement of the high molecular chain. The elongation at break is improved by 25%-50%, reflecting the flexibility after reinforcement. The puncture resistance is improved by 30%-60%, thanks to the reinforcing effect of the filler (such as montmorillonite and polyimide micro powder). The adhesion is improved by 50%-75%, which indicates that the adhesion of the polyester film to the adhesive layer is significantly enhanced. In addition, all the examples achieve the UL-94 V-0 level, while the ordinary PET adhesive tape only achieves the V-2 level.

[0101] In summary, the polyester film of the utility model can provide excellent mechanical strength and processing performance for the film by using high-viscosity polyethylene terephthalate. The thermoplastic polyurethane introduces an elastomer component, which makes the film have better flexibility and compliance. The silicone resin powder gives the film higher wear resistance and weather resistance, while keeping the surface smooth. Melamine cyanurate as an environmentally friendly flame retardant, cooperates with the organic modified montmorillonite, and has better flame retardant performance than conventional flame retardant additives. The addition of aromatic polyimide micro powder significantly improves the heat resistance and dielectric properties of the film, while the ordinary polyimide micro powder in the comparative example has a significant decrease in performance. The organic modified montmorillonite significantly enhances the puncture resistance, dielectric properties and flame retardance through nano-dispersion, and the performance is significantly improved compared with ordinary mineral fillers.

[0102] In addition, the utility model optimizes the process and proposes uniform dispersion under high shear conditions, so that the compatibility of the filler and the matrix material is better, and the dielectric properties, mechanical strength and flame retardance of the final film are significantly better than the comparative examples (the high shear process is not used in comparative examples 1 and 7, and the performance is significantly deteriorated). The use of fatty acid ester dispersant improves the dispersion effect of nano-filler, and the film is more uniform, smooth and defect-free. This design is omitted in the comparative example, resulting in a decrease in performance.

[0103] The utility model discloses a material formula and the synergic design of process show the following differentiating performance advantages, and the polyester film prepared has higher dielectric strength: 120kV / mm (embodiment) for the only 100kV / mm of ordinary PET adhesive tape, or about 85-110kV / mm of comparative example. Have more optimal mechanical strength and flexibility: tensile strength is 160MPa, and the breaking elongation is 110%, and the ordinary PET adhesive tape (tensile strength 120MPa, and the breaking elongation 80%) is significantly higher. Have better puncture resistance: 80N / mm, and the puncture resistance of comparative example is generally lower than 60N / mm, and the ordinary PET adhesive tape is about 50N / mm. The flame retardant property has been improved significantly: reach UL94 V-0 level, and the ordinary PET adhesive tape is only V-2 level, and comparative example 1, 3, 5 is only V-1 or lower. Have excellent adhesion: the adhesive force of adhesive tape is 30N / 25mm, and the ordinary PET adhesive tape (20N / 25mm) is significantly better, and also higher than 15-25N / 25mm of comparative example.

[0104] The blue adhesive tape prepared by the polyester film of the utility model can meet the strict requirements of the high-voltage environment of the automobile lithium battery electrical system and reduce the risk of short circuit. The UL94 V-0 level flame retardant property significantly improves the fire safety of the lithium battery packaging material. The physical protection ability of the battery shell is enhanced, especially in complex environments. The excellent flexibility can enhance the adhesion of the adhesive tape on irregular surfaces and reduce the warping and cracking phenomenon in the adhesion process. Through the optimization of fillers and process, the service life of the film is significantly prolonged, which is suitable for the environmental requirements of long-term use. The adhesion between the adhesive layer and the base film is improved, which ensures the stability of the adhesive tape in harsh environments such as high temperature and high humidity.

[0105] Through the synergistic effect between materials (such as the complex effect of aromatic polyimide and organic modified montmorillonite), the performance of the polyester film bag of the utility model is not simply added, but is the result of the interaction of materials. This innovative combination solves the balance problem between high dielectric, high mechanical strength and flexibility, and has a significant technical breakthrough for similar products.

[0106] In summary, the utility model and comparative example 1-8 and conventional PET adhesive tape show significant performance advantages, especially in dielectric strength, flexibility, puncture resistance and flame retardancy. These characteristics directly correspond to the strict requirements of automobile lithium battery shell packaging and provide comprehensive protection for safety, reliability and environmental adaptability.

[0107] Those skilled in the art should understand that, although the utility model is described in the manner of multiple embodiments, not every embodiment contains only one independent technical solution. The description is only for the sake of clarity, those skilled in the art should understand the specification as a whole and understand the technical solutions involved in each embodiment as being combined into different embodiments to understand the protection scope of the utility model.

[0108] The above merely describes the specific embodiments of the utility model, and is not used to limit the scope of the utility model. Any equivalent changes, modifications and combinations made by those skilled in the art without departing from the concept and principle of the utility model shall belong to the protection scope of the utility model.

Claims

1. A blue tape for bundling and packing a battery of a new energy electric vehicle, characterized in that, The blue adhesive tape is composed of a surface PET transparent film (1), a middle blue adhesive layer (2), a bottom PET transparent film (3) and a back blue adhesive layer (4).

2. The blue tape of claim 1, wherein, The outer side of the back blue adhesive layer (4) is attached with a PET release film (5).

3. The blue tape of claim 1, wherein, The thickness of the surface PET transparent film (1) is 50-85 μm.

4. The blue tape of claim 1, wherein, The thickness of the bottom PET transparent film (3) is 50-85 μm.

5. The blue tape of claim 1, wherein, The thickness of the blue adhesive tape is 185-275 μm.

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