Insulating tape as well as preparation method and application thereof

Abstract

The invention relates to an insulating adhesive tape as well as a preparation method and application thereof. The insulating adhesive tape comprises a polyolefin insulating base material layer and an acrylic acid pressure-sensitive adhesive layer which are sequentially stacked, the polyolefin insulating base material layer is prepared from the following raw materials in parts by weight: 80-100 parts of polyolefin resin and 0.5-2 parts of a cross-linking agent; the acrylic pressure-sensitive adhesive layer is prepared from the following raw materials in parts by weight: 20 to 80 parts of acrylate polymer, 20 to 80 parts of epoxy resin A, 5 to 20 parts of epoxy resin B, 5 to 20 parts of epoxy diluent and 0.5 to 5 parts of photoinitiator. By designing the structure of the insulating tape and the formula of each layer and combining the characteristics of high insulation, aging resistance, flame retardance and environmental protection of the polyolefin insulating base material layer and the excellent adhesive property of the acrylic acid pressure-sensitive adhesive layer, the prepared insulating tape has excellent insulation protection, environment-resistant stability and installation adaptability; the problem that an existing adhesive tape is unbalanced in insulation and bonding performance is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of adhesive tape, in particular to an insulating adhesive tape and a preparation method and application thereof. BACKGROUND

[0002] With the upgrading of the new energy industry, cylindrical batteries have become core energy storage elements due to their high energy density and long cycle life. As a key component of thermal management, the insulation protection between the water-cooled plate and the battery module directly determines the safety of the system. The current mainstream insulation scheme has significant defects: first, ordinary insulating adhesive tapes using polyvinyl chloride (PVC), polyethylene terephthalate (PET) and other substrates have low bonding strength (peeling strength ≤5 N / 25mm), are prone to falling off after installation due to vibration, and PVC has poor flame retardancy, releases toxic gases during combustion, and the insulation resistance of PET decreases by more than 30% under high temperature and high humidity; second, PET-based UV-cured insulation glue has an insulation resistance of only 1x10¹²-5x10¹² Ω·cm, which cannot meet the high-end insulation requirements; third, the traditional spray insulation paint scheme has high equipment investment and energy consumption, is prone to pinholes leading to insulation failure, and has a yield of less than 80%.

[0003] Therefore, how to provide an insulating adhesive tape with insulation protection, strong bonding and convenient installation has become a problem to be solved at present. SUMMARY

[0004] To solve the above technical problems, the present application provides an insulating adhesive tape and a preparation method and application thereof. By designing the structure and formula of each layer of the insulating adhesive tape, combining the high insulation, aging resistance and flame-retardant environmental protection properties of the polyolefin insulating substrate layer and the excellent bonding performance of the acrylic pressure-sensitive adhesive layer, the prepared insulating adhesive tape has excellent insulation protection, environmental stability and installation adaptability, solving the imbalance between insulation and bonding performance of existing adhesive tapes.

[0005] To achieve this purpose, the present application adopts the following technical solutions:

[0006] In a first aspect, the present application provides an insulating adhesive tape, which comprises a polyolefin insulating substrate layer and an acrylic pressure-sensitive adhesive layer stacked in sequence.

[0007] The preparation raw materials of the polyolefin insulating substrate layer include, by weight: 80-100 parts of polyolefin resin and 0.5-2 parts of crosslinking agent.

[0008] The preparation raw materials of the acrylic pressure-sensitive adhesive layer include, by weight: 20-80 parts of acrylic ester polymer, 20-80 parts of epoxy resin A, 5-20 parts of epoxy resin B, 5-20 parts of epoxy diluent and 0.5-5 parts of photoinitiator.

[0009] Wherein, 80-100 parts may be, for example, 80 parts, 85 parts, 90 parts, 95 parts, or 100 parts, etc.; 0.5-2 parts may be, for example, 0.5 parts, 1 part, 1.5 parts, or 2 parts, etc.; 20-80 parts may be, for example, 20 parts, 30 parts, 40 parts, 50 parts, 60 parts, 70 parts, or 80 parts, etc.; 5-20 parts may be, for example, 5 parts, 10 parts, 15 parts, or 20 parts, etc.; 0.5-5 parts may be, for example, 0.5 parts, 1 part, 2 parts, 3 parts, 4 parts, or 5 parts, etc.

[0010] The insulating adhesive tape provided by the present application provides excellent insulation by designing the formula of the polyolefin insulating base material layer, and the polyolefin resin forms a three-dimensional network structure after cross-linking, thereby improving the heat resistance of the insulating adhesive tape; the formula of the acrylic pressure-sensitive adhesive layer is designed to enable rapid bonding with the material at room temperature (20-30℃), and the cured product has excellent bonding strength; the combination of the polyolefin insulating base material layer and the acrylic pressure-sensitive adhesive layer combines the high insulation, aging resistance, and flame-retardant environmental protection properties of the polyolefin insulating base material layer with the excellent bonding performance of the acrylic pressure-sensitive adhesive layer, thereby solving the imbalance between insulation and bonding performance of existing adhesive tapes.

[0011] Preferably, the polyolefin insulating base material layer has a single-layer structure or a multi-layer structure.

[0012] The polyolefin insulating base material layer with a multi-layer structure can be matched with different polyolefin resins to realize the regulation of insulation, aging resistance, and flame retardance.

[0013] Preferably, when the polyolefin insulating base material layer has a multi-layer structure, the interlayer bonding force thereof is ≥5 N / cm, for example, 5 N / cm, 6 N / cm, 7 N / cm, 8 N / cm, 9 N / cm, or 10 N / cm, etc.

[0014] The interlayer bonding force is the interlayer bonding force between the polyolefin insulating base material layer and the acrylic pressure-sensitive adhesive layer.

[0015] In the present application, the test method of the interlayer bonding force is as follows: the preparation principle of the acrylic pressure-sensitive adhesive layer provided by the present application is mixed, and is applied between two polyolefin films prepared from the preparation raw materials of the polyolefin insulating base material layer provided by the present application; after drying at 90℃ for 1.5 min, a test sample is prepared; the test sample is subjected to 180° peeling at a constant speed (100 mm / min±10 mm / min), and the peeling force (N / cm) is measured.

[0016] Preferably, when the polyolefin insulating base material layer has a multi-layer structure, it includes an inner layer arranged on one side of the acrylic pressure-sensitive adhesive layer and an outer layer arranged on the side of the inner layer away from the acrylic pressure-sensitive adhesive layer.

[0017] Preferably, the outer layer is a single-layer structure or a multi-layer structure.

[0018] Preferably, the thickness ratio of the inner layer and the outer layer is 1:(0.3-2), which can be 1:0.3, 1:0.5, 1:1, 1:1.5, or 1:2, etc.

[0019] The present application limits the thickness ratio of the inner layer and the outer layer to be 1:(0.3-2). If the inner layer is too thin, the adhesion between the polyolefin insulation substrate layer and the acrylic pressure-sensitive adhesive layer is insufficient. If the outer layer is too thin, the insulation tape is easily scratched by the edge of the water-cooled plate.

[0020] Preferably, the thickness of the polyolefin insulation substrate layer is 0.05-0.2 mm, which can be 0.05 mm, 0.06 mm, 0.08 mm, 0.1 mm, 0.12 mm, 0.14 mm, 0.15 mm, 0.16 mm, 0.18 mm, or 0.2 mm, etc.

[0021] Preferably, the cross-linking degree of the polyolefin insulation substrate layer is 50-80%, which can be 50%, 60%, 70%, or 80%, etc.

[0022] The cross-linking degree is tested by the reflux extraction method.

[0023] Preferably, the thickness of the acrylic pressure-sensitive adhesive layer is 20-100 μm, which can be 20 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, or 100 μm, etc.

[0024] Preferably, the insulation tape further comprises a release film arranged on the side of the polyolefin insulation substrate layer away from the acrylic pressure-sensitive adhesive layer.

[0025] Preferably, the material of the release film is PET.

[0026] Preferably, the thickness of the release film is 25-75 μm, which can be 25 μm, 30 μm, 40 μm, 50 μm, 60 μm, or 75 μm, etc.

[0027] Preferably, the release force of the release film is 5-15 g / in, which can be 5 g / in, 6 g / in, 8 g / in, 10 g / in, 12 g / in, 14 g / in, or 15 g / in, etc.

[0028] The present application further provides the release film as a protective layer to ensure the safety and convenience of the insulation tape during storage, transportation, and use, and further limits the release force of the release film to ensure that the release film is easy to peel off and does not damage the acrylic pressure-sensitive adhesive layer during use.

[0029] Preferably, the polyolefin resin comprises a combination of a homopolymer polyolefin resin and / or a copolymer polyolefin resin.

[0030] Preferably, the homopolymer polyolefin resin comprises any one or a combination of at least two of polyethylene (PE), polypropylene (PP), modified polyethylene or modified polypropylene.

[0031] Preferably, the copolymer polyolefin resin comprises any one or a combination of at least two of cyclic olefin copolymer (COC), polyolefin elastomer (POE), thermoplastic vulcanizate (TPV) or ethylene-glycidyl methacrylate copolymer.

[0032] The polyolefin resin selected by the present application, wherein the homopolymer polyolefin resin can provide excellent flexibility for the insulating adhesive tape, and the copolymer polyolefin resin can provide excellent insulation performance and interface bonding capacity with the acrylic pressure-sensitive adhesive layer for the insulating adhesive tape.

[0033] Preferably, the polyolefin resin comprises a combination of a homopolymer polyolefin resin and a copolymer polyolefin resin.

[0034] Preferably, the polyolefin resin comprises a combination of a homopolymer polyolefin resin and a copolymer polyolefin resin.

[0035] Preferably, the polyolefin resin comprises a combination of a homopolymer polyolefin resin and a copolymer polyolefin resin.

[0036] The present application can ensure that the polyolefin insulating substrate layer has excellent insulation performance, and at the same time, increase the dimensional stability and compatibility and interface bonding force of the polyolefin insulating substrate layer with other components by selecting polyethylene, cyclic olefin copolymer and / or ethylene-glycidyl methacrylate copolymer as the polyolefin resin.

[0037] When the polyolefin insulating substrate layer is a multi-layer structure, a combination of polyethylene and cyclic olefin copolymer outer layer and polypropylene and polyolefin elastomer inner layer can be selected, the combination of polyethylene and cyclic olefin copolymer focuses on high insulation and scratch resistance, which can effectively avoid scratching and damage during installation of the water-cooled plate. And the combination of polyethylene and polyolefin elastomer focuses on high flexibility and strong adhesion, and the elongation at break of the polyolefin insulating substrate layer after combination is ≥500%, which is suitable for curved surface adhesion of the water-cooled plate, and there is no wrinkle and cracking in the bending R10-90°.

[0038] Preferably, the polyolefin resin is a combination of polyethylene and cyclic olefin copolymer, preferably the mass ratio of the polyethylene and cyclic olefin copolymer is (1-7):1, for example, it can be 1:1, 2:1, 3:1, 4:1, 5:1, 6:1 or 7:1, etc.

[0039] Preferably, the polyolefin resin is a combination of polyethylene and ethylene-glycidyl methacrylate copolymer, preferably the mass ratio of the polyethylene and ethylene-glycidyl methacrylate copolymer is (1-5):1, for example, it can be 1:1, 2:1, 3:1, 4:1 or 5:1, etc.

[0040] Preferably, the crosslinking agent includes trimethylolpropane triacrylate (TMPTA) and / or triallyl isocyanurate (TAIC).

[0041] Preferably, the crosslinking agent includes a combination of trimethylolpropane triacrylate and triallyl isocyanurate.

[0042] The present application can efficiently promote the polyolefin resin molecular chain to form a three-dimensional network crosslinking structure by introducing a crosslinking agent, effectively improve the heat resistance, mechanical strength and dimensional stability of the substrate, avoid the thermal shrinkage deformation of the substrate under high temperature working condition of the water cooling system, and at the same time, the introduction of the crosslinking agent can reduce the amount of other additives, reduce the cost and avoid the influence of other additives on the mechanical properties of the polyolefin insulation substrate layer.

[0043] Preferably, the preparation raw material of the polyolefin insulation substrate layer further includes 10-30 parts of flame retardant A and / or 0.1-0.5 parts of antioxidant by weight.

[0044] For example, 10-30 parts can be 10 parts, 12 parts, 14 parts, 15 parts, 16 parts, 18 parts, 20 parts, 22 parts, 24 parts, 25 parts, 26 parts, 28 parts or 30 parts, etc.; 0.1-0.5 parts can be 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts or 0.5 parts, etc.

[0045] Preferably, the flame retardant A includes a halogen-free flame retardant.

[0046] Preferably, the halogen-free flame retardant includes any one or a combination of at least two of magnesium hydroxide, red phosphorus and phosphorus-nitrogen synergistic flame retardants.

[0047] Preferably, the phosphorus-nitrogen synergistic flame retardant includes a combination of alkyl phosphate and melamine cyanurate.

[0048] Preferably, the magnesium hydroxide flame retardant includes ultra-fine coated magnesium hydroxide.

[0049] Preferably, the red phosphorus flame retardant includes microcapsule coated red phosphorus.

[0050] The preferred halogen-free flame retardant of the present application has excellent compatibility with the polyolefin resin, can fully meet the environmental protection requirements of halogen-free flame retardation, and has excellent adaptability to the preparation process of the polyolefin insulation base layer. By introducing the halogen-free flame retardant into the insulation tape, the flame retardation of the insulation tape can be further improved without affecting the insulation performance, and the UL94 V0 level flame retardation effect can be achieved.

[0051] Preferably, the antioxidant comprises antioxidant 1330 and / or antioxidant 168.

[0052] Preferably, the antioxidant comprises a combination of antioxidant 1330 and antioxidant 168.

[0053] The present application can inhibit the aging of the polyolefin insulation base layer under high temperature and high humidity, increase the stability of the polyolefin insulation base layer, and prolong the service life of the polyolefin insulation base layer by using two antioxidants in combination.

[0054] Preferably, the polyolefin insulation base layer is prepared by a preparation method comprising:

[0055] The raw materials for preparing the polyolefin insulation base layer are mixed, extruded and granulated, cast into a film, and pre-crosslinked to obtain the polyolefin insulation base layer.

[0056] Preferably, the mixing is carried out in a high-speed mixer.

[0057] Preferably, the speed of the high-speed mixer is 800-1000 r / min, for example, it can be 800 r / min, 850 r / min, 900 r / min, 950 r / min, or 1000 r / min, etc.

[0058] Preferably, the mixing time is 5-8 min, for example, it can be 5 min, 5.5 min, 6 min, 6.5 min, 7 min, 7.5 min, or 8 min, etc.

[0059] Preferably, the extrusion granulation is carried out in a twin-screw extruder.

[0060] Preferably, the temperature of the feeding section of the twin-screw extruder is 180-190℃, the temperature of the plasticizing section is 190-210℃, and the temperature of the die section is 210-220℃.

[0061] For example, 180-190℃ can be 180℃, 182℃, 184℃, 185℃, 186℃, 188℃, or 190℃, etc.

[0062] Preferably, the D50 particle size of the obtained polyolefin masterbatch after the extrusion granulation is 2-3 mm, for example, it can be 2 mm, 2.2 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.8 mm or 3 mm, etc.

[0063] Preferably, the temperature of the cast film formation is 180-220℃, for example, it can be 180℃, 190℃, 200℃, 210℃ or 220℃, etc.

[0064] Preferably, the cast film formation includes single-layer cast film formation or multi-layer co-extrusion cast film formation.

[0065] Preferably, the thickness deviation of the cast film formation is ≤0.005 mm, for example, it can be 0 mm, 0.01 mm, 0.02 mm, 0.03 mm, 0.04 mm or 0.05 mm, etc.

[0066] Preferably, the pre-crosslinking treatment includes electron beam irradiation crosslinking.

[0067] Preferably, the irradiation voltage of the electron beam irradiation crosslinking is 400-600 KeV, for example, it can be 400 KeV, 450 KeV, 500 KeV, 550 KeV or 600 KeV, etc.

[0068] Preferably, the irradiation dose of the electron beam irradiation crosslinking is 60-180 kGy, for example, it can be 60 kGy, 80 kGy, 100 kGy, 120 kGy, 140 kGy, 150 kGy, 160 kGy or 180 kGy, etc.

[0069] Preferably, the raw materials for preparing the acrylate polymer include 90-110 parts of acrylate monomer, 1-10 parts of functional monomer, 0.01-0.05 parts of free radical initiator and 30-70 parts of solvent.

[0070] Among them, 90-110 parts can be 90 parts, 95 parts, 100 parts, 105 parts or 110 parts, etc.; 1-10 parts can be 1 part, 2 parts, 4 parts, 5 parts, 6 parts, 8 parts or 10 parts, etc.; 0.01-0.05 parts can be 0.01 parts, 0.02 parts, 0.04 parts or 0.05 parts, etc.; 30-70 parts can be 30 parts, 40 parts, 50 parts, 60 parts or 70 parts, etc.

[0071] Preferably, the acrylate monomer includes any one or a combination of at least two of methyl acrylate, methyl methacrylate, butyl acrylate or isooctyl acrylate.

[0072] Preferably, the functional monomer comprises any one or a combination of at least two of glycidyl methacrylate, hydroxyethyl acrylate or acrylamide.

[0073] Preferably, the free radical initiator comprises azobisisobutyronitrile.

[0074] Preferably, the solvent comprises ethyl acetate.

[0075] Preferably, the acrylate polymer is prepared by a preparation method comprising:

[0076] The raw materials of the acrylate polymer are mixed and reacted to obtain the acrylate polymer.

[0077] Preferably, the temperature of the reaction is 80-90℃, for example, it can be 80℃, 82℃, 84℃, 85℃, 86℃, 88℃ or 90℃, etc., and the time of the reaction is 3-5 h, for example, it can be 3 h, 3.5 h, 4 h, 4.5 h or 5 h, etc.

[0078] Preferably, the epoxy resin A comprises any one or a combination of at least two of bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin or bisphenol F type epoxy resin.

[0079] Preferably, the epoxy resin B comprises a modified epoxy resin.

[0080] Preferably, the modified epoxy resin comprises any one or a combination of at least two of polyurethane modified epoxy resin, dimer acid modified epoxy resin, carboxyl-terminated butadiene-acrylonitrile rubber modified epoxy resin or nano-modified epoxy resin.

[0081] The polyurethane modified epoxy resin used in the present application can effectively improve the bonding performance of the acrylate pressure-sensitive adhesive layer and the polyolefin insulation substrate layer, and can prevent the delamination phenomenon caused by the laminated stamping.

[0082] Preferably, the epoxy diluent comprises any one or a combination of at least two of glycidyl ether, glycidyl ester or glycidyl amine.

[0083] Preferably, the photoinitiator comprises any one or a combination of at least two of diazonium salt, diaryliodonium salt, diarylsulfonium salt or iron arene salt.

[0084] Preferably, the raw materials of the acrylate pressure-sensitive adhesive layer further comprise any one or a combination of at least two of tackifying resin 1-30 parts, flame retardant B 1-30 parts or filler 1-5 parts by weight.

[0085] The present application can further introduce tackifying resin into the formula of the acrylic pressure-sensitive adhesive layer to improve the initial adhesion, introduce flame retardant to further enhance the flame retardance of the insulating tape, and introduce filler to improve the coating property of the adhesive.

[0086] 1-30 parts, for example, can be 1 part, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts or 30 parts, etc.; 1-5 parts, for example, can be 1 part, 2 parts, 3 parts, 4 parts or 5 parts, etc.

[0087] Preferably, the tackifying resin comprises rosin terpene phenolic resin.

[0088] Preferably, the flame retardant B comprises organic phosphorus-based flame retardant.

[0089] Preferably, the filler comprises fumed silica.

[0090] In the second aspect, the present application provides a preparation method of the insulating tape according to the first aspect, and the preparation method comprises the following steps:

[0091] (1) mixing the preparation raw materials of the acrylic pressure-sensitive adhesive layer to obtain an acrylic pressure-sensitive adhesive solution;

[0092] (2) coating the acrylic pressure-sensitive adhesive solution obtained in step (1) on one side surface of the polyolefin insulating substrate, and after drying, obtaining the insulating tape.

[0093] Preferably, the temperature of the mixing in step (1) is 20-30℃, for example, can be 20℃, 22℃, 24℃, 25℃, 26℃, 28℃ or 30℃, etc., and the mixing time is 1-2 h, for example, can be 1 h, 1.2 h, 1.4 h, 1.5 h, 1.6 h, 1.8 h or 2 h, etc.

[0094] Preferably, the coating in step (2) is knife coating.

[0095] Preferably, the coating precision of the knife coating is ±(1-2) μm, for example, can be 1 μm, 1.5 μm, 2 μm, -1 μm, -1.5 μm or -2 μm, etc.

[0096] Preferably, the temperature of the drying is 80-100℃, for example, can be 80℃, 85℃, 90℃, 95℃ or 100℃, etc., and the curing time is 1-3 min, for example, can be 1 min, 1.5 min, 2 min, 2.5 min or 3 min, etc.

[0097] Preferably, after the drying in step (2), the method further comprises the steps of arranging a release film on the side of the polyolefin insulating substrate layer away from the acrylic pressure-sensitive adhesive layer and winding.

[0098] In a third aspect, the present application provides an application of the insulating adhesive tape in a battery.

[0099] The insulating adhesive tape provided by the present application can provide insulation protection for a water-cooled plate of a cylindrical battery, and is suitable for new energy automobile power battery packs, large-scale energy storage power stations and other scenes with high requirements for insulation performance, bonding strength and environmental stability.

[0100] When the insulating adhesive tape is used, a UV light source with a wavelength of 360-370 nm (for example, 360 nm, 362 nm, 364 nm, 365 nm, 366 nm, 368 nm or 370 nm, etc.) is used for irradiation (the energy density is 1000-5000 mJ / cm 2 , for example, 1000 mJ / cm 2 , 2000 mJ / cm 2 , 3000 mJ / cm 2 , 4000 mJ / cm 2 , 5000 mJ / cm 2 , etc.), and the time is 1-300 s (for example, 1 s, 50 s, 100 s, 150 s, 200 s, 250 s or 300 s, etc.). After the release film is removed, the insulating adhesive tape is attached to the surface of the water-cooled plate of the cylindrical battery or other materials, and then a pressure of 0.5-1 MPa (for example, 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa or 1 MPa, etc.) is applied at room temperature (20-30℃, for example, 20℃, 22℃, 24℃, 25℃, 26℃, 28℃ or 30℃, etc.) for 30-60 s (30 s, 40 s, 50 s or 60 s, etc.), and then the curing is completed by standing at room temperature (20-30℃) for 1-100 h (for example, 1 h, 20 h, 40 h, 50 h, 60 h, 80 h or 100 h, etc.).

[0101] Compared with the prior art, the present application has at least the following beneficial effects:

[0102] (1) The present application designs the structure and formula of each layer of the insulating adhesive tape, combines the high insulation, aging resistance and flame-retardant environmental protection properties of the polyolefin insulation substrate layer and the excellent bonding performance of the acrylic pressure-sensitive adhesive layer, and obtains the insulating adhesive tape with excellent insulation protection, environmental stability and installation adaptability, which solves the imbalance between insulation and bonding performance of the existing adhesive tape.

[0103] (2) The insulating adhesive tape provided by the application can provide insulation protection for the water-cooled plate of the battery, especially the cylindrical battery, and is suitable for new energy automobile power battery packs, large-scale energy storage power stations and other scenes with strict requirements on insulation performance, bonding strength and environmental stability.

[0104] (3) The insulating adhesive tape provided by the application is easy to prepare, only conventional extrusion and coating equipment is used, the process parameters are easy to control, the production cost is reduced by 20%-30% compared with imported similar products, and the initial pressure-sensitive property is provided, the tape can be attached by applying pressure at room temperature, is suitable for the curved water-cooled plate of the cylindrical battery, and the installation efficiency is improved by more than 50% compared with spraying insulating paint, and the installation yield can reach more than 98%.

[0105] (4) The insulating resistance of the insulating adhesive tape provided by the application can reach 5x10 13 -1.3x10 14 Ω·cm, the peeling strength can reach 8.5-17.5 N / 25 mm, the insulating resistance only decreases by 0.17-8% after double 85 test, the peeling strength only decreases by 0.06-5.2%, the shear strength can reach 7.8-8.7 MPa, no water seepage / slight water seepage but no cracking is observed after salt spray aging test, the flame retardant performance can reach UL94-2021 V0-V1 level, and the appearance is good, no toxic gas is released during combustion, and the RoHS and REACH instructions are met. DETAILED DESCRIPTION

[0106] In order to facilitate the understanding of the present application, the present application is illustrated as follows. It should be understood by those skilled in the art that the examples are only used to help understand the present application and should not be regarded as a specific limitation on the present application.

[0107] In the following specific embodiments of the present application, the specific information of the materials used is as follows:

[0108] Polyethylene PE, purchased from Sinopec, model LF182;

[0109] Polypropylene PP, purchased from Sinopec, model T30S;

[0110] Cyclic olefin copolymer COC, purchased from Bruckner, model 6013;

[0111] Ethylene-glycidyl methacrylate copolymer, purchased from SK, model 8840;

[0112] Polyolefin elastomer POE, purchased from Dow, model 8450;

[0113] Thermoplastic vulcanized rubber TPV, purchased from Exxon Mobil, model 101-87;

[0114] Flame retardant A, superfine coated magnesium hydroxide, purchased from Hangzhou Jihewen New Material Co., Ltd., model SS-MH6P;

[0115] Flame retardant A, phosphorus-nitrogen synergistic flame retardant, alkyl phosphate (purchased from Japan ADEKA, model FP-2100JC) and melamine cyanurate in a mass ratio of 2:1;

[0116] Acrylate polymer, the acrylate polymer used in the following examples and comparative examples of the present application is prepared by the following preparation method, which comprises:

[0117] Butyl acrylate 70 parts, methyl acrylate 25 parts, glycidyl methacrylate 5 parts, AIBN 0.03 parts and ethyl acetate 50 parts are mixed, and after reaction at 85℃ for 4h, the acrylate polymer is obtained;

[0118] Epoxy resin A, bisphenol A type epoxy resin NPEL-128E, purchased from Nanya;

[0119] Epoxy resin A, hydrogenated bisphenol A type epoxy resin, purchased from Anhui Xinyuan;

[0120] Epoxy resin A, bisphenol F type epoxy resin, purchased from Nantong Xingchen;

[0121] Epoxy resin B, polyurethane modified epoxy resin EM1033, purchased from Luhe High-tech;

[0122] Epoxy resin B, polyurethane modified epoxy resin EPU73B, purchased from Arkema;

[0123] Epoxy resin B, carboxyl-terminated butadiene acrylonitrile rubber modified epoxy resin, purchased from Hengxin New Material;

[0124] Epoxy diluent, benzyl glycidyl ether (XY692), purchased from Anhui Xinyuan;

[0125] Tackifying resin, rosin terpene phenolic resin T-803L, purchased from Arakawa Chemical Industries, Ltd.;

[0126] Photoinitiator, photoinitiator 261;

[0127] Flame retardant B, organic phosphorus flame retardant OP935, purchased from Clariant

[0128] Filler, fumed silica AEROSIL 150, purchased from WACKER;

[0129] Release film, PET, purchased from Kunshan Caiyi Paper Plastic Products Co., Ltd.;

[0130] Commercially available PVC substrate, purchased from Suzhou Huasu Plastic Co., Ltd.

[0131] Example 1

[0132] The embodiment provides an insulating adhesive tape, which comprises a polyolefin insulating base material layer (including an outer layer of 0.05 mm and an inner layer of 0.05 mm), an acrylic pressure-sensitive adhesive layer (50 µm) and a release film (50 µm) which are sequentially stacked;

[0133] The preparation raw materials of the outer layer comprise, in parts by weight, PE 70 parts, COC 10 parts, TAIC 1.5 parts, antioxidant 168 0.2 parts and a phosphorus-nitrogen synergistic flame retardant 12 parts;

[0134] The preparation raw materials of the inner layer comprise, in parts by weight, PP 60 parts, POE 40 parts, TAIC 1.5 parts, antioxidant 168 0.2 parts and a phosphorus-nitrogen synergistic flame retardant 12 parts;

[0135] The preparation raw materials of the acrylic pressure-sensitive adhesive layer comprise, in parts by weight, an acrylate polymer 60 parts, a hydrogenated bisphenol A type epoxy resin 40 parts, a polyurethane modified epoxy resin EPU73B 15 parts, a benzyl glycidyl ether 15 parts and a photoinitiator 261 3 parts.

[0136] The preparation method of the polyolefin insulating base material layer comprises the following steps:

[0137] (S1) the preparation raw materials of the outer layer and the inner layer are respectively mixed, and then respectively fed into a high-speed mixer, pre-mixed at a rotating speed of 900 r / min for 6 min, and then the obtained pre-mixing materials are respectively added into double-screw extruders, extruded and granulated by controlling the temperature of a feeding section to be 200 ℃, the temperature of a plasticizing section to be 210 ℃ and the temperature of a die head to be 220 ℃, and after extrusion and granulation, the materials are respectively water-cooled and granulated to obtain the outer layer polyolefin master batch and the inner layer polyolefin master batch with a particle size of 2 mm;

[0138] (S2) the outer layer polyolefin master batch and the inner layer polyolefin master batch obtained in step (S1) are respectively fed into two single-screw extruders, mixed and extruded at a die head (200 ℃) to control the thickness of the outer layer to be 0.05 mm and the thickness of the inner layer to be 0.5 mm, and a polyolefin film is obtained;

[0139] (S3) the polyolefin film obtained in step (S2) is crosslinked by electron beam irradiation, the irradiation voltage is 600 KeV, the dose is 150 kGy, and a polyolefin insulating base material is obtained, and the crosslinking degree is 70%;

[0140] The preparation method of the insulating adhesive tape comprises the following steps:

[0141] (1) the preparation raw materials of the acrylic pressure-sensitive adhesive layer are mixed at 25 ℃ for 1.5 h to obtain an acrylic pressure-sensitive adhesive solution;

[0142] (2) The acrylic pressure-sensitive adhesive solution obtained in step (1) is coated on one side surface of the polyolefin insulating base material (coating thickness of the acrylic pressure-sensitive adhesive solution: 50 μm) using a doctor blade, dried at 90°C for 1.5 min, and then laminated with a release film to obtain the insulating adhesive tape.

[0143] Example 2

[0144] The insulating adhesive tape provided in this example comprises, in order, a polyolefin insulating base material layer (0.1 mm), an acrylic pressure-sensitive adhesive layer (30 μm), and a release film (25 μm);

[0145] The polyolefin insulating base material layer is prepared from the following raw materials by weight: PE 60 parts, COC 20 parts, ethylene-glycidyl methacrylate copolymer 20 parts, TMPTA 0.8 parts, TAIC 0.5 parts, antioxidant 1330 0.1 part, antioxidant 168 0.2 part, and ultra-fine coated magnesium hydroxide 20 parts;

[0146] The acrylic pressure-sensitive adhesive layer is prepared from the following raw materials by weight: acrylic ester polymer 50 parts, bisphenol A type epoxy resin 50 parts, polyurethane-modified epoxy resin EM1033 10 parts, benzyl glycidyl ether 10 parts, and photoinitiator 261 2.5 parts, rosin terpene phenol resin 3 parts, phosphorus flame retardant 5 parts, and fumed silica 1 part.

[0147] The polyolefin insulating base material layer is prepared by the following steps:

[0148] (S1) The raw materials for the polyolefin insulating base material layer are put into a high-speed mixer, and pre-mixed at a rotation speed of 900 r / min for 6 min. The pre-mixed material is then added into a twin-screw extruder, and extruded and granulated at a temperature of 190°C for the feeding section, 200°C for the plasticizing section, and 210°C for the die head. After extrusion and granulation, the material is water-cooled and cut into particles with a particle size of 2 mm to obtain the polyolefin master batch;

[0149] (S2) The polyolefin master batch obtained in step (S1) is put into a single-screw extruder, and single-layer cast into a film at 200°C. The temperature of the casting roll is 40°C, and the film thickness is controlled to be 0.1 mm to obtain the polyolefin film;

[0150] (S3) The polyolefin film obtained in step (S2) is crosslinked by electron beam irradiation at an irradiation voltage of 500 KeV and a dose of 120 kGy to obtain the polyolefin insulating base material, and the crosslinking degree is 60%;

[0151] The insulating adhesive tape is prepared by the following steps:

[0152] (1) The raw materials for preparing the acrylic pressure-sensitive adhesive layer were mixed at 25°C for 1.5 h to obtain an acrylic pressure-sensitive adhesive solution;

[0153] (2) The acrylic pressure-sensitive adhesive solution obtained in step (1) was coated on one side surface of the polyolefin insulating substrate (coating thickness of the acrylic pressure-sensitive adhesive solution was 30 μm) by using a doctor blade, and then dried at 85°C for 2 min, followed by laminating a release film and winding to obtain the insulating adhesive tape.

[0154] Example 3

[0155] The insulating adhesive tape provided in this example comprises a polyolefin insulating substrate layer (comprising an outer layer of 0.05 mm and an inner layer of 0.05 mm), an acrylic pressure-sensitive adhesive layer (80 μm) and a release film (75 μm) which are sequentially stacked;

[0156] The raw materials for preparing the outer layer comprise, by weight fraction: PE 50 parts, COC 50 parts, TMPTA 0.8 parts, antioxidant 168 0.5 parts and superfine coated magnesium hydroxide 30 parts;

[0157] The raw materials for preparing the inner layer comprise, by weight fraction: PP 20 parts, TPV 80 parts, TMPTA 0.8 parts, antioxidant 168 0.5 parts and superfine coated magnesium hydroxide 30 parts;

[0158] The raw materials for preparing the acrylic pressure-sensitive adhesive layer comprise, by weight fraction: acrylic ester polymer 80 parts, bisphenol F type epoxy resin 20 parts, carboxyl-terminated nitrile rubber modified epoxy resin 8 parts, benzyl glycidyl ether 8 parts and photoinitiator 261 4 parts.

[0159] The preparation method of the polyolefin insulating substrate layer comprises the following steps:

[0160] (S1) The raw materials for preparing the outer layer and the inner layer were mixed respectively, and then were respectively fed into a high-speed mixer for premixing at a rotation speed of 900 r / min for 6 min. The obtained premixing materials were respectively added into a twin-screw extruder, and the temperature of the feeding section was controlled at 200°C, the temperature of the plasticizing section was controlled at 210°C, and the temperature of the die head was controlled at 220°C for extruding and granulating. After extruding and granulating, the materials were respectively water-cooled and pelletized to obtain the outer layer polyolefin master batch and the inner layer polyolefin master batch with a particle size of 2 mm;

[0161] (S2) The outer layer polyolefin master batch and the inner layer polyolefin master batch obtained in step (S1) were respectively fed into two single-screw extruders, and were mixed and extruded at a die head (200°C) to obtain a polyolefin film with a thickness of 0.04 mm for the outer layer and a thickness of 0.04 mm for the inner layer;

[0162] (S3) The polyolefin film obtained in step (S2) is crosslinked by electron beam irradiation, the irradiation voltage is 600 KeV, the dose is 160 kGy, to obtain a polyolefin insulating base material, the crosslinking degree is 75%;

[0163] The preparation method of the insulating adhesive tape comprises the following steps:

[0164] (1) The preparation raw materials of the acrylic pressure-sensitive adhesive layer are mixed at 25°C for 1.5 h to obtain an acrylic pressure-sensitive adhesive solution;

[0165] (2) The acrylic pressure-sensitive adhesive solution obtained in step (1) is coated on one side surface of the polyolefin insulating base material by using a doctor blade (the coating thickness of the acrylic pressure-sensitive adhesive solution is 80 μm), and then dried at 80°C for 3 min, and then a release film is attached and wound to obtain the insulating adhesive tape.

[0166] Example 4

[0167] The embodiment provides an insulating adhesive tape, which is different from example 2 in that the preparation raw materials of the polyolefin insulating base material layer comprise, according to weight parts: COC 100 parts, TMPTA 0.8 parts, TAIC 0.5 parts, antioxidant 1330 0.1 part, antioxidant 168 0.2 part and superfine coated magnesium hydroxide 20 parts, the crosslinking degree of the polyolefin insulating base material layer is 58%, and the rest is the same as in example 2.

[0168] Example 5

[0169] The embodiment provides an insulating adhesive tape, which is different from example 2 in that the preparation raw materials of the polyolefin insulating base material layer comprise, according to weight parts: PE 75 parts, PP 25 parts, TMPTA 0.8 parts, TAIC 0.5 parts, antioxidant 1330 0.1 part, antioxidant 168 0.2 part and superfine coated magnesium hydroxide 20 parts, the crosslinking degree of the polyolefin insulating base material layer is 55%, and the rest is the same as in example 2.

[0170] Example 6

[0171] The embodiment provides an insulating adhesive tape, which comprises, in sequence, a polyolefin insulating base material layer (0.1 mm), an acrylic pressure-sensitive adhesive layer (50 μm) and a release film (50 μm);

[0172] The preparation raw materials of the polyolefin insulating base material layer comprise, according to weight parts: PE 70 parts, COC 10 parts, TAIC 1.5 parts, antioxidant 168 0.2 part and phosphorus-nitrogen synergistic flame retardant 12 parts;

[0173] The preparation raw materials of the acrylic pressure-sensitive adhesive layer include, by weight fraction, 60 parts of an acrylic ester polymer, 40 parts of a hydrogenated bisphenol A type epoxy resin, 15 parts of a polyurethane modified epoxy resin EPU73B, 15 parts of a benzyl glycidyl ether, and 3 parts of a photoinitiator 261.

[0174] The preparation method of the polyolefin insulating base material layer includes the following steps:

[0175] (S1) Put the preparation raw materials of the polyolefin insulating base material layer into a high-speed mixer, and premix at a rotation speed of 900 r / min for 6 min. Then, add the premixed material into a twin-screw extruder, control the temperature of the feeding section to be 190℃, the temperature of the plasticizing section to be 200℃, and the temperature of the die head to be 210℃, and perform extrusion granulation. After the extrusion granulation, the material is water-cooled and pelletized to obtain polyolefin master granules with a particle size of 2 mm;

[0176] (S2) Put the polyolefin master granules obtained in step (S1) into a single-screw extruder, and single-layer flow cast a film at 200℃, with the casting roll temperature being 40℃ and the film thickness being controlled to be 0.1 mm, to obtain a polyolefin film;

[0177] (S3) Crosslink the polyolefin film obtained in step (S2) by electron beam irradiation, with the irradiation voltage being 500 KeV and the dose being 120 kGy, to obtain a polyolefin insulating base material, and the crosslinking degree is 55%;

[0178] The preparation method of the insulating adhesive tape includes the following steps:

[0179] (1) Mix the preparation raw materials of the acrylic pressure-sensitive adhesive layer at 25℃ for 1.5 h to obtain an acrylic pressure-sensitive adhesive solution;

[0180] (2) Apply the acrylic pressure-sensitive adhesive solution obtained in step (1) to one side surface of the polyolefin insulating base material by blade coating (the coating thickness of the acrylic pressure-sensitive adhesive solution is 50 μm), and dry at 90℃ for 1.5 min. Then, laminate a release film and wind up to obtain the insulating adhesive tape.

[0181] Example 7

[0182] The insulating adhesive tape provided in the embodiment includes, in sequence, a polyolefin insulating base material layer (0.1 mm), an acrylic pressure-sensitive adhesive layer (50 μm), and a release film (50 μm);

[0183] The preparation raw materials of the polyolefin insulating base material layer include, by weight fraction, 60 parts of PP, 40 parts of POE, 1.5 parts of TAIC, 0.2 parts of an antioxidant 168, and 12 parts of a phosphorus-nitrogen synergistic flame retardant;

[0184] The preparation raw materials of the acrylic pressure-sensitive adhesive layer include, by weight fraction, 60 parts of an acrylate polymer, 40 parts of a hydrogenated bisphenol A type epoxy resin, 15 parts of a polyurethane modified epoxy resin EPU73B, 15 parts of a benzyl glycidyl ether, and 3 parts of a photoinitiator 261.

[0185] The preparation method of the polyolefin insulating base material layer includes the following steps:

[0186] (S1) Put each preparation raw material of the polyolefin insulating base material layer into a high-speed mixer, and premix at a rotation speed of 900 r / min for 6 min. Then, add the premixed material into a twin-screw extruder, control the temperature of the feeding section to be 190℃, the temperature of the plasticizing section to be 200℃, and the temperature of the die head to be 210℃, and perform extrusion granulation. After the extrusion granulation, the material is water-cooled and pelletized to obtain a polyolefin master batch with a particle size of 2 mm;

[0187] (S2) Put the polyolefin master batch obtained in step (S1) into a single-screw extruder, and single-layer cast a film at 200℃, with the casting roll temperature being 40℃ and the film thickness being controlled to be 0.1 mm, to obtain a polyolefin film;

[0188] (S3) Crosslink the polyolefin film obtained in step (S2) by electron beam irradiation, with the irradiation voltage being 500 KeV and the dose being 120 kGy, to obtain a polyolefin insulating base material, and the crosslinking degree is 60%;

[0189] The preparation method of the insulating adhesive tape includes the following steps:

[0190] (1) Mix the preparation raw materials of the acrylic pressure-sensitive adhesive layer at 25℃ for 1.5 h to obtain an acrylic pressure-sensitive adhesive solution;

[0191] (2) Apply the acrylic pressure-sensitive adhesive solution obtained in step (1) to one side surface of the polyolefin insulating base material by using a doctor blade (the coating thickness of the acrylic pressure-sensitive adhesive solution is 50 μm), and dry at 90℃ for 1.5 min. Then, laminate a release film and wind up to obtain the insulating adhesive tape.

[0192] Example 8

[0193] The insulating adhesive tape provided in this example includes, in sequence, a polyolefin insulating base material layer (0.1 mm), an acrylic pressure-sensitive adhesive layer (50 μm), and a release film (50 μm);

[0194] The preparation raw materials of the polyolefin insulating base material layer include, by weight fraction, 70 parts of PE, 10 parts of COC, 0.5 parts of TMPTA, 0.5 parts of TAIC, 0.2 parts of an antioxidant 1330, 0.3 parts of an antioxidant 168, and 16 parts of a phosphorus-nitrogen synergistic flame retardant;

[0195] The preparation raw materials of the acrylic pressure-sensitive adhesive layer include, in terms of weight parts, 60 parts of an acrylate polymer, 40 parts of a hydrogenated bisphenol A type epoxy resin, 15 parts of a polyurethane modified epoxy resin EPU73B, 15 parts of a benzyl glycidyl ether, and 3 parts of a photoinitiator 261.

[0196] The preparation method of the polyolefin insulating base material layer includes the following steps:

[0197] (S1) The preparation raw materials of the polyolefin insulating base material layer are put into a high-speed mixer, pre-mixed at a rotating speed of 900 r / min for 6 min, and then the pre-mixed material is added into a twin-screw extruder, the temperature of the feeding section is controlled to be 190℃, the temperature of the plasticizing section is controlled to be 200℃, and the temperature of the die head is controlled to be 210℃ for extrusion granulation, and after the extrusion granulation, the material is water-cooled and pelletized to obtain polyolefin master granules with a particle size of 2 mm;

[0198] (S2) The polyolefin master granules obtained in step (S1) are put into a single-screw extruder, and a single-layer film is cast at 200℃, the casting roll temperature is 40℃, and the film thickness is controlled to be 0.1 mm, to obtain a polyolefin film;

[0199] (S3) The polyolefin film obtained in step (S2) is crosslinked by electron beam irradiation, the irradiation voltage is 500 KeV, and the dose is 120 kGy, to obtain a polyolefin insulating base material, and the crosslinking degree is 56%;

[0200] The preparation method of the insulating adhesive tape includes the following steps:

[0201] (1) The preparation raw materials of the acrylic pressure-sensitive adhesive layer are mixed at 25℃ for 1.5 h to obtain an acrylic pressure-sensitive adhesive solution;

[0202] (2) The acrylic pressure-sensitive adhesive solution obtained in step (1) is coated on one side surface of the polyolefin insulating base material by using a doctor blade (the coating thickness of the acrylic pressure-sensitive adhesive solution is 50 μm), and then dried at 90℃ for 1.5 min, and then a release film is attached and wound to obtain the insulating adhesive tape.

[0203] Example 9

[0204] The difference between the insulating adhesive tape of the present example and that of Example 8 is that the preparation raw materials of the polyolefin insulating base material layer include, in terms of weight parts, 40 parts of PE, 40 parts of COC, 0.5 parts of TMPTA, 0.5 parts of TAIC, 0.2 parts of antioxidant 1330, 0.3 parts of antioxidant 168, and 16 parts of a phosphorus-nitrogen synergistic flame retardant, and the crosslinking degree of the polyolefin insulating base material layer is 65%, and the rest are the same as those of Example 8.

[0205] Example 10

[0206] The embodiment provides an insulating adhesive tape, which is different from the embodiment 8 in that the preparation raw material of the polyolefin insulating base material layer comprises 75 parts of PE, 10 parts of COC, 0.5 part of TMPTA, 0.5 part of TAIC, 0.2 part of antioxidant 1330, 0.3 part of antioxidant 168 and 16 parts of a phosphorus-nitrogen synergistic flame retardant according to weight parts, the crosslinking degree of the polyolefin insulating base material layer is 60%, and the rest is the same as the embodiment 8.

[0207] Embodiment 11

[0208] The embodiment provides an insulating adhesive tape, which is different from the embodiment 8 in that the preparation raw material of the polyolefin insulating base material layer comprises 45 parts of PE, 45 parts of COC, 0.5 part of TMPTA, 0.5 part of TAIC, 0.2 part of antioxidant 1330, 0.3 part of antioxidant 168 and 16 parts of a phosphorus-nitrogen synergistic flame retardant according to weight parts, the crosslinking degree of the polyolefin insulating base material layer is 70%, and the rest is the same as the embodiment 8.

[0209] Comparative example 1

[0210] The comparative example provides an insulating adhesive tape, which is different from the embodiment 2 in that the polyolefin insulating base material layer in the embodiment 2 is replaced by a PET base material layer (0.1 mm), and the rest is the same as the embodiment 2.

[0211] Comparative example 2

[0212] The comparative example provides an insulating adhesive tape, which is different from the embodiment 2 in that the polyolefin insulating base material layer in the embodiment 2 is replaced by a commercially available PVC base material (0.1 mm), and the rest is the same as the embodiment 2.

[0213] Test method

[0214] The insulating adhesive tape provided by the application is irradiated by using a 365 nm UV light source (the energy density is 3000 mJ / cm 2 , and the irradiation time is 2 s), the release film is removed after irradiation, the insulating adhesive tape is attached to the surface of a cylindrical battery water cooling plate or other materials, 0.8 MPa pressure is applied at room temperature (25 DEG C) for 40 s, curing is completed at room temperature (25 DEG C) for 20 h, and the following performance tests are carried out:

[0215] (1) Insulating resistance (Ω·cm): tested according to GB / T 1410-2006;

[0216] (2) Shear strength (MPa): tested according to GBT 7124;

[0217] (3) Peeling strength (N / 25 mm): tested according to GB / T 2792-2016;

[0218] (4) Salt spray aging resistance test: tested according to GB / T 10125-2021, aging time is 168 h;

[0219] (5) Flame retardant grade: tested according to UL94-2021;

[0220] (6) Stability (%): double 85 test (85℃, 85%RH, 1600 h) is conducted, and the insulation resistance and the peel strength reduction rate after high temperature and high humidity test are tested;

[0221] (7) Appearance: a 90° chamfer of R10 is punched out from the center of the long side of the sample after bonding, and whether cracks or wrinkles appear on the appearance is observed.

[0222] The test results are shown in Table 1-2 below:

[0223] Table 1

[0224]

[0225] Table 2

[0226]

[0227] From the test results, it can be seen that:

[0228] (1) From Examples 1 to 11, it can be seen that, by designing the structure of the insulating tape and the formula of each layer, and combining the high insulation, aging resistance and flame-retardant environmental protection properties of the polyolefin insulating substrate layer and the excellent bonding performance of the acrylic pressure-sensitive adhesive layer, the insulating tape prepared has excellent insulation protection, environmental stability and installation adaptability, and solves the imbalance between the insulation and bonding performance of the existing tape. The insulating tape provided by the present application has an insulation resistance of 5×10 13 -1.3×10 14 Ω·cm, a peel strength of 8.5-17.5 N / 25 mm, an insulation resistance reduction of only 0.17-8% after double 85 test, a peel strength reduction of only 0.06-5.2%, a shear strength of 7.8-8.7 MPa, no water penetration / slight water penetration but no cracking after salt spray aging resistance test, a flame retardant performance of UL94-2021 V0-V1 grade, and good appearance, and is suitable for cylindrical battery curved water cooling plates, and meets the stringent requirements of insulation performance, bonding strength and environmental stability in various scenes.

[0229] (2) As can be seen from Example 1 and Examples 6-7, when the polyolefin insulating base material layer is a multi-layer structure, a combination of polyethylene (PE) and cyclic olefin copolymer (COC) outer layer and polypropylene (PP) and polyolefin elastomer (POE) inner layer can be selected, and the combination of polypropylene and cyclic olefin copolymer focuses on high insulation and scratch resistance, which can effectively avoid scratching and damage during installation of the water cooling plate. Compared with a single-layer structure, different polyolefin resins can be matched to realize the regulation of insulation, aging resistance and flame retardance.

[0230] (3) As can be seen from Examples 8-11, by further limiting the mass ratio of polyethylene (PE) and cyclic olefin copolymer (COC) in the polyolefin insulating base material layer, more excellent insulation, aging resistance and flame retardance can be obtained.

[0231] (4) As can be seen from the examples and Comparative Examples 1-2, compared with the insulating adhesive tape containing a PET base material layer, the insulating adhesive tape provided by the present application has excellent insulation, aging resistance, and provides the adhesive tape with flame retardance; compared with the insulating adhesive tape containing a commercially available ordinary PVC base material, after the plasticizer in the PVC base material migrates to the interface, the physical adsorption and chemical combination of the adhesive layer and the base material will be weakened, and in severe cases, the adhesive tape will be detached and fail due to "adhesive layer remaining on the surface of the base material"; the PVC is prone to hydrolysis under high temperature and high humidity, which not only destroys the molecular chain structure, but also corrodes the surface of the base material and the interface with the adhesive layer, so the peeling strength is seriously deteriorated, while the insulating adhesive tape provided by the present application has more excellent aging resistance.

[0232] The applicant declares that the above description is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. It should be understood by those skilled in the art that any changes or replacements within the technical scope disclosed by the present application can be easily thought of by those skilled in the art, and all fall within the protection scope and disclosure scope of the present application.

Claims

1. An insulating tape, characterized by, The insulation tape comprises a polyolefin insulation base layer and an acrylic pressure-sensitive adhesive layer which are stacked in sequence; The polyolefin insulation base layer is prepared from raw materials including, by weight, 80-100 parts of a polyolefin resin and 0.5-2 parts of a crosslinking agent; The acrylic pressure-sensitive adhesive layer is prepared from raw materials including, by weight, 20-80 parts of an acrylic ester polymer, 20-80 parts of an epoxy resin A, 5-20 parts of an epoxy resin B, 5-20 parts of an epoxy diluent, and 0.5-5 parts of a photoinitiator.

2. The insulating tape according to claim 1, wherein The polyolefin insulation base layer has a single-layer structure or a multi-layer structure; Preferably, when the polyolefin insulation base layer has a multi-layer structure, it comprises an inner layer disposed on one side of the acrylic pressure-sensitive adhesive layer and an outer layer disposed on the side of the inner layer away from the acrylic pressure-sensitive adhesive layer; Preferably, the outer layer has a single-layer structure or a multi-layer structure; Preferably, the thickness ratio of the inner layer to the outer layer is 1:(0.3-2); Preferably, the polyolefin insulation base layer has a thickness of 0.05-0.2 mm; Preferably, the polyolefin insulation base layer has a crosslinking degree of 50-80%.

3. The insulating tape according to claim 1 or 2, characterized by The acrylic pressure-sensitive adhesive layer has a thickness of 20-100 µm.

4. The insulating tape according to any one of claims 1 to 3, characterized in that, The insulation tape further comprises a release film disposed on the side of the polyolefin insulation base layer away from the acrylic pressure-sensitive adhesive layer; Preferably, the release film is made of PET; Preferably, the release film has a thickness of 25-75 µm; Preferably, the release film has a release force of 5-15 g / in.

5. The insulating tape according to any one of claims 1 to 4, characterized in that, The polyolefin resin comprises a homopolymer polyolefin resin and / or a copolymer polyolefin resin; Preferably, the homopolymer polyolefin resin comprises any one or a combination of at least two of polyethylene, polypropylene, modified polyethylene, or modified polypropylene; Preferably, the copolymer polyolefin resin comprises any one or a combination of at least two of a cyclic olefin copolymer, a polyolefin elastomer, a thermoplastic vulcanizate, or an ethylene-glycidyl methacrylate copolymer; Preferably, the polyolefin resin comprises a combination of a homopolymer polyolefin resin and a copolymer polyolefin resin; Preferably, the polyolefin resin comprises a combination of a homopolymer polyolefin resin and a copolymer polyolefin resin in a mass ratio of (1-10):1; Preferably, the polyolefin resin is a combination of a homopolymer polyolefin resin and a copolymer polyolefin resin, the homopolymer polyolefin resin is polyethylene, and the copolymer polyolefin resin is a cyclic olefin copolymer and / or an ethylene-glycidyl methacrylate copolymer; Preferably, the polyolefin resin is a combination of polyethylene and a cyclic olefin copolymer, preferably in a mass ratio of (1-7):1; Preferably, the polyolefin resin is a combination of polyethylene and an ethylene-glycidyl methacrylate copolymer, preferably in a mass ratio of (1-5):1; Preferably, the crosslinking agent comprises trimethylolpropane triacrylate and / or triallyl isocyanurate; Preferably, the crosslinking agent comprises a combination of trimethylolpropane triacrylate and triallyl isocyanurate. Preferably, the raw materials for preparing the polyolefin insulation substrate layer further comprise, in parts by weight, 10-30 parts of a flame retardant A and / or 0.1-0.5 parts of an antioxidant; Preferably, the flame retardant A comprises a halogen-free flame retardant; Preferably, the halogen-free flame retardant comprises any one or a combination of at least two of a magnesium hydroxide-based flame retardant, a red phosphorus-based flame retardant, or a phosphorus-nitrogen synergistic flame retardant; Preferably, the phosphorus-nitrogen synergistic flame retardant comprises a combination of alkyl phosphate and melamine cyanurate; Preferably, the antioxidant comprises antioxidant 1330 and / or antioxidant 168; Preferably, the antioxidant comprises a combination of antioxidant 1330 and antioxidant 168.

6. The insulating tape according to any one of claims 1 to 5, wherein The polyolefin insulation substrate layer is prepared by a preparation method comprising: mixing the raw materials for preparing the polyolefin insulation substrate layer, extruding and granulating, casting into a film, and pre-crosslinking to obtain the polyolefin insulation substrate layer; Preferably, the mixing is performed in a high-speed mixer; Preferably, the rotation speed of the high-speed mixer is 800-1000 r / min; Preferably, the mixing time is 5-8 min; Preferably, the extruding and granulating is performed in a twin-screw extruder; Preferably, the temperature of the feeding section of the twin-screw extruder is 180-190℃, the temperature of the plasticizing section is 190-210℃, and the temperature of the die section is 210-220℃; Preferably, the D50 particle size of the polyolefin master batch obtained after the extruding and granulating is 2-3 mm; Preferably, the temperature of the casting into a film is 180-220℃; Preferably, the casting into a film comprises single-layer casting into a film or multi-layer co-extrusion casting into a film; Preferably, the pre-crosslinking comprises electron beam irradiation crosslinking; Preferably, the irradiation voltage of the electron beam irradiation crosslinking is 400-600 KeV; Preferably, the irradiation dose of the electron beam irradiation crosslinking is 60-180 kGy.

7. The insulating tape according to any one of claims 1 to 6, wherein The raw materials for preparing the acrylate polymer comprise 90-110 parts of an acrylate monomer, 1-10 parts of a functional monomer, 0.01-0.05 parts of a free radical initiator, and 30-70 parts of a solvent; Preferably, the acrylate monomer comprises any one or a combination of at least two of methyl acrylate, methyl methacrylate, butyl acrylate, or isooctyl acrylate; Preferably, the functional monomer comprises any one or a combination of at least two of glycidyl methacrylate, hydroxyethyl acrylate, or acrylamide; Preferably, the free radical initiator comprises azobisisobutyronitrile; Preferably, the solvent comprises ethyl acetate; The acrylate polymer is prepared by a preparation method comprising: mixing the raw materials for preparing the acrylate polymer, and performing a reaction to obtain the acrylate polymer; Preferably, the temperature of the reaction is 80-90℃, and the reaction time is 3-5 h; Preferably, the epoxy resin A comprises any one or a combination of at least two of bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, or bisphenol F type epoxy resin; Preferably, the epoxy resin B comprises a modified epoxy resin; Preferably, the modified epoxy resin comprises any one or a combination of at least two of a polyurethane modified epoxy resin, a dimer acid modified epoxy resin, a carboxyl-terminated nitrile rubber modified epoxy resin or a nano-modified epoxy resin; Preferably, the epoxy diluent comprises any one or a combination of at least two of a glycidyl ether, a glycidyl ester or a glycidyl amine; Preferably, the photoinitiator comprises any one or a combination of at least two of a diazonium salt, a diaryliodonium salt, a diarylsulfonium salt or an iron arene salt; Preferably, the raw materials for preparing the acrylic pressure-sensitive adhesive layer further comprise any one or a combination of at least two of an adhesion resin 1-30 parts, a flame retardant B 1-30 parts or a filler 1-5 parts by weight; Preferably, the adhesion resin comprises a rosin terpene phenolic resin; Preferably, the flame retardant B comprises an organic phosphorus-based flame retardant; Preferably, the filler comprises fumed silica.

8. A method of producing the insulating tape according to any one of claims 1 to 7, characterized by, The preparation method comprises the following steps: (1) mixing the raw materials for preparing the acrylic pressure-sensitive adhesive layer to obtain an acrylic pressure-sensitive adhesive solution; (2) coating the acrylic pressure-sensitive adhesive solution obtained in step (1) on one side surface of the polyolefin insulating substrate, and after drying, obtaining the insulating adhesive tape.

9. The method of producing an insulating tape according to claim 8, wherein The temperature for mixing in step (1) is 20-30°C, and the mixing time is 1-2 h; Preferably, the temperature for drying is 80-100°C, and the curing time is 1-3 min; Preferably, after drying in step (2), the method further comprises the step of arranging a release film on the side of the polyolefin insulating substrate layer away from the acrylic pressure-sensitive adhesive layer and winding.

10. Use of the insulating adhesive tape according to any one of claims 1-7 in a battery.

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