Electrolyte-resistant enhanced acrylate pressure-sensitive adhesive, preparation method thereof and termination adhesive tape

Abstract

The invention discloses an electrolyte-resistant enhanced acrylate pressure-sensitive adhesive, a preparation method thereof and a termination adhesive tape. The pressure-sensitive adhesive is prepared from the following raw materials in parts by weight: 14 to 18 parts of 2-ethylhexyl acrylate, 2 to 4 parts of acrylic acid, 7 to 8 parts of butyl acrylate, 3 to 5 parts of dodecyl acrylate, 1 to 3 parts of 4-hydroxybutyl acrylate, 1 to 2 parts of dicyclopentadiene oxyethyl acrylate, 30 to 35 parts of first solvent, 0.3 to 0.45 part of initiator, 1 to 4 parts of bromo-maleic anhydride and 0.2 to 0.3 part of catalyst. The preparation method of the acrylate pressure-sensitive adhesive is simple to operate and high in production efficiency. The pressure-sensitive adhesive tape provided by the invention has good high temperature resistance and electrolyte resistance, can avoid undesirable phenomena such as degumming, adhesive residue, layering, warping, decoloration and the like, and can maintain good adhesiveness and uniform and stable color in an electrolyte soaking environment.

Description

Technical Field

[0001] The invention relates to the field of adhesive materials, and in particular to an electrolyte-resistant enhanced acrylate pressure-sensitive adhesive, a preparation method thereof and a termination tape. Background Art

[0002] As the most popular rechargeable battery, lithium-ion batteries are widely used in portable electronic products, electric vehicles, energy storage and other fields. With the rapid development of high-capacity positive and negative electrode materials and high-voltage electrolytes, the energy density of lithium-ion batteries continues to increase, but this also puts higher requirements on the insulation, fixing and protection materials in the battery manufacturing process.

[0003] Traditional acrylic pressure-sensitive adhesives are prone to blackening and deterioration, glue dissolution, etc. after long-term contact with lithium-ion electrolytes, affecting the safety and service life of the battery. In addition, the inorganic pigments added to traditional colored acrylic adhesives are often prone to phase separation, which not only affects the uniformity and performance stability of the pressure-sensitive adhesive, but may also affect the automated identification and bonding accuracy in the subsequent production process. Therefore, it is particularly important to develop an acrylic pressure-sensitive adhesive with high electrolyte resistance, excellent dispersion effect and good optical recognition performance. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an electrolyte-resistant enhanced acrylic pressure-sensitive adhesive, a preparation method thereof and a termination tape in view of the deficiencies in the above-mentioned prior art. The pressure-sensitive adhesive of the present invention adopts a specially formulated acrylic monomer copolymer as a base resin, is modified by grafting maleic anhydride groups, and is made by adding inorganic pigments, curing agents and solvents in a specific proportion; the introduction of maleic anhydride groups significantly improves the compatibility and dispersibility of the resin and the inorganic pigment, so that the pigment can be evenly and stably dispersed in the adhesive layer; at the same time, the specially formulated acrylic monomer copolymer gives the adhesive layer excellent electrolyte resistance, and can remain stable in a high-temperature electrolyte environment. Another object of the present invention is to provide a method for preparing an electrolyte-resistant solvent-based acrylic pressure-sensitive adhesive, which has a simple process, is easy to operate, and has high production efficiency. The resulting pressure-sensitive tape has good high-temperature resistance and electrolyte resistance, and can maintain good adhesion and uniform and stable color in an environment of high-temperature electrolyte immersion.

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the present invention is: in the first aspect of the present invention, an electrolyte-resistant enhanced acrylic pressure-sensitive adhesive is provided, comprising the following raw materials in parts by weight: 14-18 parts of 2-ethylhexyl acrylate, 2-4 parts of acrylic acid, 7-8 parts of butyl acrylate, 3-5 parts of dodecyl acrylate, 1-3 parts of 4-hydroxybutyl acrylate, 1-2 parts of dicyclopentadienyloxyethyl acrylate, 30-35 parts of a first solvent, 0.3-0.45 parts of an initiator, 1-4 parts of bromomaleic anhydride, and 0.2-0.3 parts of a catalyst.

[0006] Preferably, the solvent is a mixture of one or more of acetone, ethyl acetate and xylene.

[0007] Preferably, the initiator is azobisisobutyronitrile, benzoyl oxide or a mixture of both.

[0008] Preferably, the catalyst is triethylamine or 4-dimethylaminopyridine or a mixture of both.

[0009] Preferably, the electrolyte-resistant enhanced acrylic pressure-sensitive adhesive comprises the following raw materials in parts by weight: 14-16 parts of 2-ethylhexyl acrylate, 2-3.5 parts of acrylic acid, 7-7.5 parts of butyl acrylate, 3-3.5 parts of dodecyl acrylate, 1-2 parts of 4-hydroxybutyl acrylate, 1-1.5 parts of dicyclopentadienyloxyethyl acrylate, 30-33 parts of solvent, 0.3-0.4 parts of initiator, 1-3 parts of brominated maleic anhydride, and 0.2-0.25 parts of catalyst.

[0010] The second aspect of the present invention provides a method for preparing the electrolyte-resistant enhanced acrylic pressure-sensitive adhesive as described above, comprising the following steps:

[0011] S1, take the raw materials of the formula weight portion for use;

[0012] S2. Under an inert atmosphere, 2-ethylhexyl acrylate, acrylic acid, butyl acrylate, dodecyl acrylate, 4-hydroxybutyl acrylate, dicyclopentadienyloxyethyl acrylate and the first solvent are placed in a reaction kettle, mixed and stirred until uniform, and heated to 75-80° C. and maintained at the temperature;

[0013] S3, adding the initiator dropwise within 0.8-1h, and continuing to stir the reaction at 75-80°C for 2-3h to obtain a first reaction solution;

[0014] S4, raising the temperature to 80-85°C, adding bromomaleic anhydride to the first reaction solution, and then adding the catalyst dropwise within 0.1-0.5h, and continuing to stir and react at 80-86°C for 1-1.5h;

[0015] S5. After the reaction is completed, the reaction is cooled and the material is discharged to obtain the electrolyte-resistant enhanced acrylic pressure-sensitive adhesive.

[0016] A third aspect of the present invention provides a termination tape comprising a release film layer, an acrylate adhesive layer and a substrate layer stacked in sequence, wherein the raw materials for preparing the acrylate adhesive layer include the electrolyte-resistant enhanced acrylate pressure-sensitive adhesive as described above.

[0017] Preferably, the raw materials for preparing the acrylate adhesive layer also include inorganic pigment, curing agent and second solvent, and in the raw materials for preparing the acrylate adhesive layer, the mass ratio of electrolyte-resistant enhanced acrylate pressure-sensitive adhesive: inorganic pigment: curing agent: second solvent is 100:1-5:1-10:20-50.

[0018] Preferably, the inorganic pigment is at least one of iron blue, cobalt green and cobalt blue, the second solvent is ethyl ester, and the curing agent is at least one of epoxy resin curing agent and isocyanate curing agent;

[0019] The material of the substrate layer is PET, PP or PI, and the thickness is 7-50 μm; the thickness of the acrylic adhesive layer is 3-50 μm.

[0020] Preferably, the termination tape is prepared by the following method:

[0021] The electrolyte-resistant enhanced acrylic pressure-sensitive adhesive, inorganic pigment, curing agent and second solvent are uniformly mixed, the obtained acrylic adhesive is uniformly coated on the release film layer, baked and cured, the adhesive surface of the formed acrylic adhesive layer is attached to the substrate layer, and ripened to obtain the termination tape.

[0022] The beneficial effects of the present invention are:

[0023] The invention provides an electrolyte-resistant enhanced acrylate pressure-sensitive adhesive, a preparation method thereof and a termination tape. The preparation method of the acrylate pressure-sensitive adhesive of the invention is simple to operate and has high production efficiency. The produced acrylate pressure-sensitive adhesive has excellent high temperature resistance and electrolyte resistance and is suitable for large-scale industrial promotion.

[0024] The pressure-sensitive adhesive tape of the present invention has good high temperature resistance and electrolyte resistance, can avoid the occurrence of undesirable phenomena such as degumming, residual glue, delamination, warping, discoloration, etc., and can maintain good adhesiveness and uniform and stable color in an environment immersed in electrolyte.

[0025] In the pressure-sensitive adhesive formula of the present invention, the three components of 4-hydroxybutyl acrylate, dicyclopentadienyloxyethyl acrylate and bromomaleic anhydride synergistically improve the high temperature resistance, electrolyte resistance and bonding strength of the present invention through their respective molecular structure characteristics. 4-Hydroxybutyl acrylate provides polar sites and flexible segments, enhancing adhesion and flexibility; dicyclopentadienyloxyethyl acrylate improves high temperature resistance and chemical resistance through its rigid structure and cross-linking ability; bromomaleic anhydride improves the stability and optical recognition performance of the adhesive through grafting reaction and pigment dispersibility. Through the composite combination and synergistic effect of these components, the pressure-sensitive adhesive prepared by the present invention can show excellent durability and reliability in extreme environments, and can be applied to high-demand industrial application scenarios. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with embodiments so that those skilled in the art can implement the invention with reference to the description.

[0027] It should be understood that terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0028] The test methods used in the following examples are conventional methods unless otherwise specified. The materials and reagents used in the following examples are all commercially available unless otherwise specified. In the following examples, if no specific conditions are specified, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used, if the manufacturer is not specified, are all conventional products that can be purchased commercially.

[0029] The invention provides an electrolyte-resistant enhanced acrylic pressure-sensitive adhesive, comprising the following raw materials in parts by weight: 14-18 parts of 2-ethylhexyl acrylate, 2-4 parts of acrylic acid, 7-8 parts of butyl acrylate, 3-5 parts of dodecyl acrylate, 1-3 parts of 4-hydroxybutyl acrylate, 1-2 parts of dicyclopentadienyloxyethyl acrylate, 30-35 parts of a first solvent, 0.3-0.45 parts of an initiator, 1-4 parts of bromomaleic anhydride and 0.2-0.3 parts of a catalyst.

[0030] In a preferred embodiment, the electrolyte-resistant enhanced acrylic pressure-sensitive adhesive comprises the following raw materials in parts by weight: 14-16 parts of 2-ethylhexyl acrylate, 2-3.5 parts of acrylic acid, 7-7.5 parts of butyl acrylate, 3-3.5 parts of dodecyl acrylate, 1-2 parts of 4-hydroxybutyl acrylate, 1-1.5 parts of dicyclopentadienyloxyethyl acrylate, 30-33 parts of solvent, 0.3-0.4 parts of initiator, 1-3 parts of brominated maleic anhydride, and 0.2-0.25 parts of catalyst.

[0031] In a preferred embodiment, the electrolyte-resistant enhanced acrylic pressure-sensitive adhesive comprises the following raw materials in parts by weight: 15 parts of 2-ethylhexyl acrylate, 2 parts of acrylic acid, 7 parts of butyl acrylate, 3 parts of dodecyl acrylate, 1.5 parts of 4-hydroxybutyl acrylate, 1 part of dicyclopentadienyloxyethyl acrylate, 33 parts of solvent, 0.3 parts of initiator, 2 parts of brominated maleic anhydride, and 0.2 parts of catalyst.

[0032] In a preferred embodiment, the solvent is a mixture of one or more of acetone, ethyl acetate and xylene. More preferably, the solvent is a mixture consisting of 5-7 parts of acetone, 10-20 parts of ethyl acetate and 5-10 parts of xylene.

[0033] In a preferred embodiment, the initiator is azobisisobutyronitrile, benzoyl oxide, or a mixture of the two, more preferably benzoyl oxide.

[0034] In a preferred embodiment, the catalyst is triethylamine or 4-dimethylaminopyridine or a mixture of both, more preferably 4-dimethylaminopyridine.

[0035] The present invention also provides a method for preparing the above electrolyte-resistant enhanced acrylic pressure-sensitive adhesive, comprising the following steps:

[0036] S1, take the raw materials in parts by weight of the formula for use; in a preferred embodiment, the initiator and the catalyst are both diluted with 10 times the mass of ethyl ester before use;

[0037] S2. Under an inert atmosphere, 2-ethylhexyl acrylate, acrylic acid, butyl acrylate, dodecyl acrylate, 4-hydroxybutyl acrylate, dicyclopentadienyloxyethyl acrylate and the first solvent are placed in a reaction kettle, mixed and stirred until uniform, and heated to 75-80° C. and maintained at the temperature;

[0038] S3, adding the initiator dropwise within 0.8-1h, and continuing to stir the reaction at 75-80°C for 2-3h to obtain a first reaction solution;

[0039] S4, raising the temperature to 80-85°C, adding bromomaleic anhydride to the first reaction solution, and then adding the catalyst dropwise within 0.1-0.5h, and continuing to stir and react at 80-86°C for 1-1.5h;

[0040] S5. After the reaction is completed, the reaction is cooled and the material is discharged to obtain an electrolyte-resistant enhanced acrylic pressure-sensitive adhesive.

[0041] The present invention also provides a termination tape, comprising a release film layer, an acrylate adhesive layer and a substrate layer which are stacked in sequence, wherein the raw materials for preparing the acrylate adhesive layer include the above electrolyte-resistant enhanced acrylate pressure-sensitive adhesive.

[0042] In a preferred embodiment, the raw materials for preparing the acrylate adhesive layer also include inorganic pigments, curing agents and a second solvent. Among the raw materials for preparing the acrylate adhesive layer, the mass ratio of electrolyte-resistant enhanced acrylate pressure-sensitive adhesive: inorganic pigments: curing agents: second solvent is 100:1-5:1-10:20-50.

[0043] In a preferred embodiment, the inorganic pigment is at least one of iron blue, cobalt green and cobalt blue, more preferably cobalt blue.

[0044] In a preferred embodiment, the second solvent is an ethyl ester.

[0045] In a preferred embodiment, the curing agent is at least one of an epoxy resin curing agent and an isocyanate curing agent, and more preferably a toluene diisocyanate curing agent.

[0046] The material of the substrate layer is PET, PP or PI, with a thickness of 7-50 μm; more preferably, it is PET material with a thickness of 25 μm.

[0047] The thickness of the acrylic adhesive layer is 3-50 μm, and more preferably 25 μm.

[0048] In a preferred embodiment, the termination tape is prepared by the following method:

[0049] The electrolyte-resistant enhanced acrylic pressure-sensitive adhesive, inorganic pigment, curing agent and second solvent are uniformly mixed, the obtained acrylic adhesive is uniformly coated on the release film layer, baked and cured, the adhesive surface of the formed acrylic adhesive layer is attached to the substrate layer, and ripened to obtain a termination tape.

[0050] The present invention prepares a pressure-sensitive adhesive with high electrolyte resistance, excellent high temperature resistance and good optical recognition effect by combining specific acrylate monomers and functional monomers. Among them, basic monomers such as 2-ethylhexyl acrylate, butyl acrylate, and dodecyl acrylate form a copolymer skeleton, which gives the adhesive good hydrophobicity, flexibility and weather resistance. In order to further enhance the stability and bonding strength of the pressure-sensitive adhesive in a high-temperature electrolyte environment, the present invention adopts functional monomers such as 4-hydroxybutyl acrylate, dicyclopentadienyloxyethyl acrylate and brominated maleic anhydride, which significantly improve the performance of the adhesive through their unique molecular structure and chemical reaction.

[0051] In the present invention, the hydroxyl group in 4-hydroxybutyl acrylate has a high degree of polarity and reactivity, and can undergo a cross-linking reaction under the action of brominated maleic anhydride to form a stable three-dimensional network structure. The polarity of the hydroxyl group also enhances the adhesion of the adhesive to the adherend surface, particularly under high temperature or electrolyte environment, by forming a hydrogen bond or chemical bond with the surface, the bonding performance of the pressure-sensitive adhesive is greatly improved. In addition, the flexible segment of 4-hydroxybutyl acrylate provides good flexibility, so that the pressure-sensitive adhesive will not be brittle under stress, and its tensile and shear resistance are improved simultaneously. By enhancing the cross-linking density and the flexibility of the molecular chain, 4-hydroxybutyl acrylate significantly improves the cohesion, bonding strength and durability under extreme conditions of the pressure-sensitive adhesive.

[0052] In the present invention, the molecular structure of dicyclopentadieneoxyethyl acrylate has a dicyclic structure, which provides high rigidity, thereby improving the deformation resistance of the pressure-sensitive adhesive under high temperature environment. The dicyclopentadiene structure reduces the degree of freedom of the molecular chain, increases the cohesive strength of the polymer, and enables the pressure-sensitive adhesive to still maintain morphological stability after being heated or used for a long time. In addition, the epoxy group of dicyclopentadieneoxyethyl acrylate has higher reactivity, can cross-link with other functional groups in the system (such as the hydroxyl group of 4-hydroxybutyl acrylate or the anhydride group of bromomaleic anhydride), further increasing the cross-linking density. The cross-linking reaction not only enhances the mechanical properties of the pressure-sensitive adhesive, but also improves its chemical corrosion resistance, particularly under high temperature electrolyte environment, significantly reduces the penetration and destruction of electrolyte molecules to the glue layer. The low polarity of the dicyclopentadiene structure helps to improve the hydrophobicity of the pressure-sensitive adhesive, reduces hydrolysis or dissolution phenomenon, thereby further enhancing the stability of the pressure-sensitive adhesive in the electrolyte.

[0053] In the present invention, brominated maleic anhydride is used as a grafting modifier, which has a high reactivity, and its anhydride group can undergo grafting reaction with the hydroxyl group of 4-hydroxybutyl acrylate to form a cross-linked network structure, thereby improving the cross-linking density and cohesive force of the pressure-sensitive adhesive. The introduction of brominated maleic anhydride significantly improves the dispersibility of inorganic pigments in adhesives, prevents the occurrence of pigment phase separation, and ensures the uniformity and stability of the color of the adhesive layer, which is crucial for improving the optical recognition effect. In addition, the presence of brominated maleic anhydride can further enhance the heat resistance and chemical resistance of the pressure-sensitive adhesive, ensuring that no degumming or performance degradation occurs when used for a long time in high temperature and electrolyte.

[0054] In summary, in the pressure-sensitive adhesive formula of the present invention, the three components of 4-hydroxybutyl acrylate, dicyclopentadienyloxyethyl acrylate and brominated maleic anhydride synergistically improve the high temperature resistance, electrolyte resistance and bonding strength of the present invention through their respective molecular structure characteristics. 4-Hydroxybutyl acrylate provides polar sites and flexible segments, enhancing adhesion and flexibility; dicyclopentadienyloxyethyl acrylate improves high temperature resistance and chemical resistance through its rigid structure and cross-linking ability; brominated maleic anhydride improves the stability and optical recognition performance of the adhesive through grafting reaction and pigment dispersion. Through the composite combination and synergistic effect of these components, the pressure-sensitive adhesive prepared by the present invention can show excellent durability and reliability in extreme environments, and can be applied to high-demand industrial application scenarios.

[0055] The above is the overall concept of the present invention, and detailed embodiments and comparative examples are provided below on the basis of the overall concept of the present invention to further illustrate the present invention.

[0056] Example 1

[0057] An electrolyte-resistant enhanced acrylic pressure-sensitive adhesive comprises the following raw materials in parts by weight: 14 parts of 2-ethylhexyl acrylate, 2 parts of acrylic acid, 7 parts of butyl acrylate, 3 parts of dodecyl acrylate, 2 parts of 4-hydroxybutyl acrylate, 1 part of dicyclopentadienyloxyethyl acrylate, 30 parts of solvent, 0.3 parts of benzoyl oxide (initiator), 1 part of brominated maleic anhydride, and 0.2 parts of 4-dimethylaminopyridine (catalyst); wherein the solvent is a mixture of 5 parts of acetone, 20 parts of ethyl ester, and 5 parts of xylene.

[0058] The preparation method of the pressure-sensitive adhesive comprises the following steps:

[0059] S1, take the raw materials of the formula weight parts for use, wherein the initiator and the catalyst are diluted with 10 times the mass of ethyl ester for use;

[0060] S2. Under N2 atmosphere, 2-ethylhexyl acrylate, acrylic acid, butyl acrylate, dodecyl acrylate, 4-hydroxybutyl acrylate, dicyclopentadienyloxyethyl acrylate and the first solvent (the amount added is the remaining part except the ethyl ester used to dilute the initiator and the catalyst) are placed in a reaction kettle, mixed and stirred until uniform, and the temperature is slowly raised to 75-80°C and maintained at this temperature;

[0061] S3, slowly dropwise adding all the benzoyl oxide within 1 hour, and continue stirring and reacting at 78° C. for 2 hours to obtain a first reaction solution;

[0062] S4, slowly raise the temperature to 82°C, add bromomaleic anhydride to the first reaction solution, slowly drop all the catalyst within 0.5h, and continue stirring the reaction at 82°C for 1h;

[0063] S5. After the temperature of the material in the reactor drops below 40° C., the material is discharged to obtain an electrolyte-resistant enhanced acrylic pressure-sensitive adhesive.

[0064] A termination tape, the preparation method of which comprises the following steps:

[0065] The electrolyte-resistant enhanced acrylic pressure-sensitive adhesive, toluene diisocyanate curing agent, cobalt blue paste and ethyl ester prepared above were prepared in a mass ratio of 100:2:5:40, stirred and mixed evenly to remove bubbles, and then coated on a release film layer with a thickness of 50 μm with a scraper. The adhesive was first baked at 120°C for 3 minutes to form an acrylic adhesive layer with a thickness of 25 μm, and finally laminated on a PET substrate layer with a thickness of 25 μm, and then aged in an environment of 55°C for 24 hours to obtain a termination tape.

[0066] Example 2

[0067] The invention discloses an electrolyte-resistant enhanced acrylic pressure-sensitive adhesive, comprising the following raw materials in parts by weight: 18 parts of 2-ethylhexyl acrylate, 4 parts of acrylic acid, 8 parts of butyl acrylate, 5 parts of dodecyl acrylate, 3 parts of 4-hydroxybutyl acrylate, 2 parts of dicyclopentadienyloxyethyl acrylate, 30 parts of solvent, 0.45 parts of benzoyl oxide, 4 parts of brominated maleic anhydride, and 0.3 parts of 4-dimethylaminopyridine; wherein the solvent is a mixture of 5 parts of acetone, 20 parts of ethyl acetate, and 5 parts of xylene.

[0068] The preparation method of the pressure-sensitive adhesive comprises the following steps:

[0069] S1, take the raw materials of the formula weight parts for use, wherein the initiator and the catalyst are diluted with 10 times the mass of ethyl ester for use;

[0070] S2. Under N2 atmosphere, 2-ethylhexyl acrylate, acrylic acid, butyl acrylate, dodecyl acrylate, 4-hydroxybutyl acrylate, dicyclopentadienyloxyethyl acrylate and the first solvent (the amount added is the remaining part except the ethyl ester used to dilute the initiator and the catalyst) are placed in a reaction kettle, mixed and stirred until uniform, and the temperature is slowly raised to 75-80°C and maintained at this temperature;

[0071] S3, slowly dropwise adding all the benzoyl oxide within 1 hour, and continue stirring and reacting at 78° C. for 2 hours to obtain a first reaction solution;

[0072] S4, slowly raise the temperature to 82°C, add bromomaleic anhydride to the first reaction solution, slowly drop all the catalyst within 0.5h, and continue stirring the reaction at 82°C for 1h;

[0073] S5. After the temperature of the material in the reactor drops below 40° C., the material is discharged to obtain an electrolyte-resistant enhanced acrylic pressure-sensitive adhesive.

[0074] A termination tape, the preparation method of which comprises the following steps:

[0075] The electrolyte-resistant enhanced acrylic pressure-sensitive adhesive, toluene diisocyanate curing agent, cobalt blue paste and ethyl ester prepared above were prepared in a mass ratio of 100:2:5:40, stirred and mixed evenly to remove bubbles, and then coated on a release film layer with a thickness of 50 μm with a scraper. The adhesive was first baked at 120°C for 3 minutes to form an acrylic adhesive layer with a thickness of 25 μm, and finally laminated on a PET substrate layer with a thickness of 25 μm, and then aged in an environment of 55°C for 24 hours to obtain a termination tape.

[0076] Example 3

[0077] The invention discloses an electrolyte-resistant enhanced acrylic pressure-sensitive adhesive, comprising the following raw materials in parts by weight: 15 parts of 2-ethylhexyl acrylate, 2 parts of acrylic acid, 7 parts of butyl acrylate, 3 parts of dodecyl acrylate, 1.5 parts of 4-hydroxybutyl acrylate, 1 part of dicyclopentadienyloxyethyl acrylate, 30 parts of solvent, 0.3 parts of benzoyl oxide, 2 parts of brominated maleic anhydride, and 0.2 parts of 4-dimethylaminopyridine; wherein the solvent is a mixture of 5 parts of acetone, 20 parts of ethyl acetate, and 5 parts of xylene.

[0078] The preparation method of the pressure-sensitive adhesive comprises the following steps:

[0079] S1, take the raw materials of the formula weight parts for use, wherein the initiator and the catalyst are diluted with 10 times the mass of ethyl ester for use;

[0080] S2. Under N2 atmosphere, 2-ethylhexyl acrylate, acrylic acid, butyl acrylate, dodecyl acrylate, 4-hydroxybutyl acrylate, dicyclopentadienyloxyethyl acrylate and the first solvent (the amount added is the remaining part except the ethyl ester used to dilute the initiator and the catalyst) are placed in a reaction kettle, mixed and stirred until uniform, and the temperature is slowly raised to 75-80°C and maintained at this temperature;

[0081] S3, slowly dropwise adding all the benzoyl oxide within 1 hour, and continue stirring and reacting at 78° C. for 2 hours to obtain a first reaction solution;

[0082] S4, slowly raise the temperature to 82°C, add bromomaleic anhydride to the first reaction solution, slowly drop all the catalyst within 0.5h, and continue stirring the reaction at 82°C for 1h;

[0083] S5. After the temperature of the material in the reactor drops below 40° C., the material is discharged to obtain an electrolyte-resistant enhanced acrylic pressure-sensitive adhesive.

[0084] A termination tape, the preparation method of which comprises the following steps:

[0085] The electrolyte-resistant enhanced acrylic pressure-sensitive adhesive, toluene diisocyanate curing agent, cobalt blue paste and ethyl ester prepared above were prepared in a mass ratio of 100:2:5:40, stirred and mixed evenly to remove bubbles, and then coated on a release film layer with a thickness of 50 μm with a scraper. The adhesive was first baked at 120°C for 3 minutes to form an acrylic adhesive layer with a thickness of 25 μm, and finally laminated on a PET substrate layer with a thickness of 25 μm, and then aged in an environment of 55°C for 24 hours to obtain a termination tape.

[0086] Comparative Example 1

[0087] This example is basically the same as Example 3, and the main differences are listed below.

[0088] The electrolyte-resistant enhanced acrylic pressure-sensitive adhesive in this example includes the following raw materials in parts by weight:

[0089] 15 parts of 2-ethylhexyl acrylate, 2 parts of acrylic acid, 7 parts of butyl acrylate, 3 parts of dodecyl acrylate, 1.5 parts of 4-hydroxybutyl acrylate, 30 parts of solvent, 0.3 parts of benzoyl oxide, 2 parts of bromomaleic anhydride, and 0.2 parts of 4-dimethylaminopyridine; wherein the solvent is a mixture of 5 parts of acetone, 20 parts of ethyl acetate, and 5 parts of xylene.

[0090] Comparative Example 2

[0091] This example is basically the same as Example 3, and the main differences are listed below.

[0092] The electrolyte-resistant enhanced acrylic pressure-sensitive adhesive in this example includes the following raw materials in parts by weight:

[0093] 15 parts of 2-ethylhexyl acrylate, 2 parts of acrylic acid, 7 parts of butyl acrylate, 3 parts of dodecyl acrylate, 1 part of dicyclopentadienyloxyethyl acrylate, 30 parts of solvent, 0.3 parts of benzoyl oxide, 2 parts of brominated maleic anhydride, and 0.2 parts of 4-dimethylaminopyridine; wherein the solvent is a mixture of 5 parts of acetone, 20 parts of ethyl acetate, and 5 parts of xylene.

[0094] Comparative Example 3

[0095] This example is basically the same as Example 3, and the main differences are listed below.

[0096] The electrolyte-resistant enhanced acrylic pressure-sensitive adhesive in this example includes the following raw materials in parts by weight:

[0097] 15 parts of 2-ethylhexyl acrylate, 2 parts of acrylic acid, 7 parts of butyl acrylate, 3 parts of dodecyl acrylate, 1.5 parts of 4-hydroxybutyl acrylate, 1 part of dicyclopentadienyloxyethyl acrylate, 30 parts of solvent, 0.3 parts of benzoyl oxide, and 0.2 parts of 4-dimethylaminopyridine; wherein the solvent is a mixture of 5 parts of acetone, 20 parts of ethyl acetate, and 5 parts of xylene.

[0098] Comparative Example 4

[0099] This example is basically the same as Example 3, and the main differences are listed below.

[0100] The electrolyte-resistant enhanced acrylic pressure-sensitive adhesive in this example includes the following raw materials in parts by weight:

[0101] 15 parts of 2-ethylhexyl acrylate, 2 parts of acrylic acid, 7 parts of butyl acrylate, 1.5 parts of 4-hydroxybutyl acrylate, 1 part of dicyclopentadienyloxyethyl acrylate, 30 parts of solvent, 0.3 parts of benzoyl oxide, 2 parts of brominated maleic anhydride, and 0.2 parts of 4-dimethylaminopyridine; wherein the solvent is a mixture of 5 parts of acetone, 20 parts of ethyl acetate, and 5 parts of xylene.

[0102] The following performance tests were performed on the termination tapes prepared in Examples 1-3 and Comparative Examples 1-4:

[0103] 180° peel force test: flat steel plate, peel speed is 300mm / min.

[0104] Electrolyte resistance test: Place in LiPF6 electrolyte with the same physical properties, soak at 60℃ for 24h and 85℃ for 4h.

[0105] High temperature resistance test: Flatten the steel plate, bake at 130℃ for 1h, cool to room temperature, and peel off. Qualified requirements: no deformation, no shrinkage, no fading, and stickiness.

[0106] Insulation performance test: Under 500VDC, 60s conditions, qualified requirements: insulation resistance> 1GΩ.

[0107] High voltage strength test: No breakdown under 1500VDC, 60s conditions, qualified requirement: leakage current <2mA.

[0108] The test results are shown in Tables 1 and 2 below:

[0109] Table 1 Test results of Examples 1-3

[0110]

[0111] Table 2 Test results of comparative examples 1-4

[0112]

[0113] It can be seen from the test results in Table 1 above that the performance of Example 3 meets expectations, and Example 3 is a relatively optimal solution. The electrolyte-resistant enhanced acrylic pressure-sensitive adhesive of the present invention still has a high peeling force under high-temperature electrolyte, and does not fade or leave residual adhesive, and has a uniform and bright color; the viscosity loss rate is low, the high-temperature resistance test is qualified, and it has excellent high-temperature resistance. The insulation performance test and the high-voltage strength test are both qualified. This proves that the electrolyte-resistant enhanced acrylic pressure-sensitive adhesive of the present application is an acrylic pressure-sensitive adhesive with high electrolyte resistance, excellent dispersion effect and good optical recognition performance.

[0114] As can be seen from the test results of Table 2 above, the lack of different key components can significantly affect the overall performance of the acrylic pressure-sensitive adhesive. After lacking 4-hydroxybutyl acrylate (Comparative Example 1), the bonding strength significantly decreased, and the peeling force test showed obvious residual glue phenomenon, and the glue layer easily broke in high temperature and electrolyte environment. When lacking dicyclopentadieneoxyethyl acrylate (Comparative Example 2), the peeling force and high temperature resistance decreased, but relatively still maintained a certain viscosity and stability. When lacking brominated maleic anhydride (Comparative Example 3), the uniformity and dispersibility of the glue layer significantly decreased, and serious residual glue phenomenon occurred, and electrolyte resistance and high voltage resistance strength were significantly deteriorated. Lack of lauryl acrylate (Comparative Example 4) caused the performance of the glue layer under hydrolysis and high temperature to significantly decrease, and lost necessary viscosity and insulation. Taken together, these results further prove the important role played by each key component for enhancing the electrolyte resistance, high temperature resistance and overall bonding strength of the acrylic pressure-sensitive adhesive.

[0115] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to specific details.

Claims

1. An electrolyte-resistant enhanced acrylic pressure-sensitive adhesive, characterized in that: The invention comprises the following raw materials in parts by weight: 14-18 parts of 2-ethylhexyl acrylate, 2-4 parts of acrylic acid, 7-8 parts of butyl acrylate, 3-5 parts of dodecyl acrylate, 1-3 parts of 4-hydroxybutyl acrylate, 1-2 parts of dicyclopentadienyloxyethyl acrylate, 30-35 parts of a first solvent, 0.3-0.45 parts of an initiator, 1-4 parts of bromomaleic anhydride and 0.2-0.3 parts of a catalyst.

2. The electrolyte-resistant enhanced acrylic pressure-sensitive adhesive according to claim 1, characterized in that: The solvent is a mixture of one or more of acetone, ethyl acetate and xylene.

3. The electrolyte-resistant enhanced acrylic pressure-sensitive adhesive according to claim 1, characterized in that: The initiator is one of azobisisobutyronitrile and benzoyl oxide or a mixture of the two.

4. The electrolyte-resistant enhanced acrylic pressure-sensitive adhesive according to claim 1, characterized in that: The catalyst is triethylamine or 4-dimethylaminopyridine or a mixture of the two.

5. The electrolyte-resistant enhanced acrylic pressure-sensitive adhesive according to claim 1, characterized in that: The invention comprises the following raw materials in parts by weight: 14-16 parts of 2-ethylhexyl acrylate, 2-3.5 parts of acrylic acid, 7-7.5 parts of butyl acrylate, 3-3.5 parts of dodecyl acrylate, 1-2 parts of 4-hydroxybutyl acrylate, 1-1.5 parts of dicyclopentadienyloxyethyl acrylate, 30-33 parts of solvent, 0.3-0.4 parts of initiator, 1-3 parts of bromomaleic anhydride and 0.2-0.25 parts of catalyst.

6. A method for preparing the electrolyte-resistant enhanced acrylic pressure-sensitive adhesive according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1, take the raw materials of the formula weight portion for use; S2. Under an inert atmosphere, 2-ethylhexyl acrylate, acrylic acid, butyl acrylate, dodecyl acrylate, 4-hydroxybutyl acrylate, dicyclopentadienyloxyethyl acrylate and the first solvent are placed in a reaction kettle, mixed and stirred until uniform, and heated to 75-80° C. and maintained at the temperature; S3, adding the initiator dropwise within 0.8-1h, and continuing to stir the reaction at 75-80°C for 2-3h to obtain a first reaction solution; S4, raising the temperature to 80-85°C, adding bromomaleic anhydride to the first reaction solution, and then adding the catalyst dropwise within 0.1-0.5h, and continuing to stir and react at 80-86°C for 1-1.5h; S5. After the reaction is completed, the reaction is cooled and the material is discharged to obtain the electrolyte-resistant enhanced acrylic pressure-sensitive adhesive.

7. A termination tape, characterized in that: The invention comprises a release film layer, an acrylate adhesive layer and a substrate layer which are stacked in sequence, wherein the raw materials for preparing the acrylate adhesive layer include the electrolyte-resistant enhanced acrylate pressure-sensitive adhesive according to any one of claims 1 to 5.

8. The termination tape according to claim 7, characterized in that: The raw materials for preparing the acrylate adhesive layer also include inorganic pigment, curing agent and second solvent. Among the raw materials for preparing the acrylate adhesive layer, the mass ratio of electrolyte-resistant enhanced acrylate pressure-sensitive adhesive: inorganic pigment: curing agent: second solvent is 100:1-5:1-10:20-50.

9. The termination tape according to claim 8, characterized in that: The inorganic pigment is at least one of iron blue, cobalt green and cobalt blue, the second solvent is ethyl ester, and the curing agent is at least one of epoxy resin curing agent and isocyanate curing agent; The material of the substrate layer is PET, PP or PI, and the thickness is 7-50 μm; the thickness of the acrylic adhesive layer is 3-50 μm.

10. The termination tape according to claim 9, characterized in that It is prepared by the following method: The electrolyte-resistant enhanced acrylic pressure-sensitive adhesive, inorganic pigment, curing agent and second solvent are uniformly mixed, the obtained acrylic adhesive is uniformly coated on the release film layer, baked and cured, the adhesive surface of the formed acrylic adhesive layer is attached to the substrate layer, and ripened to obtain the termination tape.

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