Secondary aging of alu / pe film processing method

Abstract

This invention provides a method for processing aluminum-plastic film with a two-stage curing process. The method includes: coating both sides of an aluminum foil with a passivation solution and drying it to obtain a passivated aluminum foil; coating one side of the passivated aluminum foil with a nylon adhesive and drying it to form a nylon adhesive layer; bonding a nylon film to the surface of the nylon adhesive layer and performing a first curing, then placing it in an organic solvent for low-temperature modification treatment; coating the other side of the passivated aluminum foil with a modified polypropylene adhesive and drying it, then bonding a modified polypropylene film and performing a second curing; finally, coating the surface of the second film layer with a lubricant and drying it. In this processing method, the modified polypropylene polymer film layer is attached to the surface of the passivated aluminum foil core layer via a modified polypropylene adhesive layer, and the nylon film layer is attached to the core layer surface via a nylon adhesive layer and subjected to low-temperature modification treatment. The combination of a two-stage heating and curing process improves the sealing strength and puncture resistance of the processed aluminum-plastic film, significantly enhancing the reliability of the aluminum-plastic film used in lithium battery products.

Description

Technical Field

[0001] This invention relates to the field of processing and manufacturing technology, and in particular to a method for processing aluminum-plastic film through secondary curing. Background Technology

[0002] Biaxially oriented polymer films are widely used as flexible packaging materials. They have excellent properties such as high tensile strength and high barrier properties, as well as excellent puncture resistance and chemical solvent resistance. They can be used in the production processes of many products such as electronic and electrical packaging, pharmaceutical packaging, and food packaging.

[0003] Rechargeable batteries can be packaged using flexible packaging materials. However, existing flexible packaging materials lack sufficient tensile strength during use, making them easily punctured. Once punctured, these materials can easily cause the rechargeable battery to catch fire, thus compromising its safety. Therefore, existing flexible materials used for battery packaging suffer from insufficient tensile strength. Summary of the Invention

[0004] This invention provides a secondary curing method for aluminum-plastic film processing, which aims to solve the problem of insufficient tensile strength in existing methods for flexible materials used in battery packaging.

[0005] In a first aspect, embodiments of the present invention provide a method for processing aluminum-plastic film with secondary curing, wherein the processing method includes the following steps:

[0006] After coating both sides of the aluminum foil with passivation solution, it is dried to obtain passivated aluminum foil;

[0007] After coating one side of the passivated aluminum foil with nylon adhesive and drying it, a nylon adhesive layer is formed.

[0008] A nylon film is bonded to the surface of the nylon adhesive layer and cured once to form a first film layer;

[0009] The passivated aluminum foil containing the first film layer is placed in an organic solvent at -45°C to -35°C for low-temperature modification treatment for 15-35 minutes; the organic solvent also contains antioxidants and flame retardants.

[0010] After low-temperature modification, the other side of the passivated aluminum foil is coated with modified polypropylene adhesive and then dried to form a modified polypropylene adhesive layer.

[0011] A modified polypropylene film is laminated onto the surface of the modified polypropylene adhesive layer and subjected to secondary curing to form a second film layer; the heating temperature of the secondary curing is higher than that of the primary curing.

[0012] After applying a lubricant to the surface of the second film layer and drying it, a lubricant layer is formed.

[0013] Preferably, before the modified polypropylene film is bonded to the surface of the modified polypropylene adhesive layer and subjected to secondary curing, the process further includes:

[0014] The modified polypropylene particles are heated and melted, and then cooled to obtain the modified polypropylene film. The heating temperature for heating and melting is 180-230℃.

[0015] Preferably, the heating temperature for the first curing is 50-70°C.

[0016] Preferably, the heating temperature for the secondary curing is 60-85°C, and the heating time for the secondary curing increases with the increase of the heating temperature.

[0017] Preferably, the heating temperature for the secondary curing is 60-70°C and the heating time is 3-5 hours;

[0018] Alternatively, the heating temperature for the secondary curing is 71-85℃ and the heating time is 20-40 hours.

[0019] Preferably, the modified polypropylene adhesive layer includes a curing agent, and the mass fraction of the curing agent in the modified polypropylene adhesive layer is 0.2-4%.

[0020] Preferably, the surface of the second film layer is further covered with a lubricant layer; the lubricant layer is composed of 25-80% erucamide and 20-75% ethanol by mass percentage.

[0021] Preferably, the modified polypropylene adhesive layer comprises modified polypropylene particles and a mixed solution, wherein the mass fraction of the modified polypropylene particles is 75-95%; and the mixed solution is composed of 35-60% butanone and 40-65% cyclohexane by mass percentage.

[0022] Preferably, the antioxidant has a mass fraction of 0.2-1.5% in the organic solvent.

[0023] Preferably, the flame retardant has a mass fraction of 0.5-2% in the organic solvent.

[0024] This invention provides a method for processing aluminum-plastic film with a two-stage curing process. The process includes: coating both sides of an aluminum foil with a passivation solution and drying it to obtain a passivated aluminum foil; coating one side of the passivated aluminum foil with a nylon adhesive and drying it to form a nylon adhesive layer; bonding a nylon film to the surface of the nylon adhesive layer and performing a first curing, then placing it in an organic solvent for low-temperature modification treatment; coating the other side of the passivated aluminum foil with a modified polypropylene adhesive and drying it, then bonding a modified polypropylene film and performing a second curing; and finally coating the surface of the second film layer with a lubricant and drying it. In this processing method, the core layer is a passivated aluminum foil, the modified polypropylene polymer film layer is attached to the core layer surface via a modified polypropylene adhesive layer, and the nylon film layer is attached to the core layer surface via a nylon adhesive layer and subjected to low-temperature modification treatment. The combination of two heating and curing processes improves the sealing strength and puncture resistance of the processed aluminum-plastic film, significantly enhancing its reliability in lithium battery products. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a flowchart of a secondary curing method for aluminum-plastic film processing provided in an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the cross-sectional structure of the aluminum-plastic film provided in an embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram illustrating the application effect of the aluminum-plastic film provided in an embodiment of the present invention;

[0029] Figure 4 This is a schematic diagram illustrating another application effect of the aluminum-plastic film provided in an embodiment of the present invention. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Description of raw materials and equipment in the examples:

[0032] Chloroform, purchased from Sinopharm Chemical Reagent Co., Ltd., model number 67-66-3;

[0033] Antioxidant, purchased from Changzhou Xince Polymer Materials Co., Ltd., model number 6683-19-8;

[0034] Flame retardant, purchased from Guangzhou Haocheng Chemical Technology Co., Ltd., model number 23128-74-7;

[0035] Aluminum foil, produced in-house, with a thickness of 0.045mm;

[0036] Butyl ketone (MEK), purchased from Sinopharm Chemical Reagent Co., Ltd., model number 78-93-3;

[0037] Erucamide, purchased from Shanghai Huayi Chemical Additives Co., Ltd., model 98%-20kg;

[0038] Ethanol, purchased from Changzhou Qidi Chemical Co., Ltd., model number 64-17-5;

[0039] The polyurethane resin, purchased from Qingdao Marine New Materials Technology Co., Ltd., model AMMT-045;

[0040] Isocyanate, purchased from Hebei Zhentian Food Additives Co., Ltd., model number 75-13-8;

[0041] Ethyl acetate, purchased from Hebei Guanlang Biotechnology Co., Ltd., model number 141-78-6;

[0042] Polypropylene, purchased from Shanghai Lianshuo Biotechnology Co., Ltd., model number 9003-07-0;

[0043] Cyclohexane, purchased from Shanghai Kaisai Chemical Co., Ltd., model number 110-82-7;

[0044] The epoxy resin was purchased from Hebei Zhentian Food Additives Co., Ltd., model number 61788-97-4.

[0045] Phosphorus, purchased from Shanghai Jinjinle Industrial Co., Ltd., model number 7723-14-0;

[0046] Passivation solution, purchased from Dongguan Biliang Cleaning Technology Co., Ltd., model SG-612;

[0047] The drying oven was purchased from Rongzheng Yida Electronic Technology Co., Ltd., model number RZYD-GZ-01.

[0048] The puncture tester, model LT-CH20A, was purchased from Shenzhen Wright Instrument Equipment Co., Ltd.

[0049] The tensile testing machine, model WDW-50M, was purchased from Jinan Zhongluchang Testing Machine Manufacturing Co., Ltd.

[0050] The hot air gun, model 2000, was purchased from Qibo Trading (Shenzhen) Co., Ltd.

[0051] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0052] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0053] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0054] Please see Figure 1 , Figure 1 This is a flowchart of a secondary curing aluminum-plastic film processing method provided in an embodiment of the present invention. As shown in the figure, the processing method includes steps S110-S170.

[0055] S110. After coating both sides of the aluminum foil with passivation solution, dry it to obtain passivated aluminum foil.

[0056] S120. After coating one side of the passivated aluminum foil with nylon adhesive, the coating is dried to form a nylon adhesive layer.

[0057] Specifically, the nylon adhesive layer is composed of 20-40% polyurethane resin, 12-50% isocyanate, and 15-30% ethyl acetate by mass percentage.

[0058] S130. A nylon film is bonded to the surface of the nylon adhesive layer and cured once to form a first film layer.

[0059] The heating temperature for the first cooking stage is 50-70℃, and the heating time for the first cooking stage is 0.5-4 hours.

[0060] S140. The passivated aluminum foil containing the first film layer is placed in an organic solvent at -45°C to -35°C for low-temperature modification treatment for 15-35 minutes; the organic solvent also contains antioxidants and flame retardants.

[0061] Antioxidants and flame retardants can be dissolved separately in an organic solvent, and the organic solvent can be cooled to a low-temperature environment to modify the first film layer through the organic solvent and the added antioxidants and flame retardants, thereby increasing the antioxidant and flame retardant properties of the first film layer; at the same time, the puncture strength of the first film layer is further improved through low-temperature modification. Specifically, the mass fraction of the antioxidant in the organic solvent is 0.2-1.5%, and the mass fraction of the flame retardant in the organic solvent is 0.5-2%. Antioxidants can be alcohol-based antioxidants, lipid-based antioxidants, etc. For example, chloroform is used as an organic solvent in this embodiment. In other embodiments, other organic solvents can be selected to dissolve the antioxidants and flame retardants. The main component of the antioxidant used in this embodiment is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], which can improve the antioxidant properties of the first film layer and the aluminum foil surface. The flame retardant can be an ethylenediamine flame retardant. For example, the main component of the flame retardant used in this embodiment is N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine, which can improve the flame retardant effect of the first film layer, thereby improving the overall heat resistance of the film material. In a more specific embodiment, the passivated aluminum foil containing the first film layer can be placed in an organic solvent at -35°C and gradually cooled to -45°C while undergoing low-temperature modification treatment. For example, the passivated aluminum foil of the first film layer is placed in an organic solvent at -35°C, and the temperature is reduced by 2°C every 5 minutes for a total soaking time of 30 minutes. When the 25th minute of soaking is reached, the temperature of the organic solvent is reduced to -45°C and the immersion is continued for another 5 minutes to complete the entire low-temperature modification process.

[0062] S150. After the passivated aluminum foil has undergone low-temperature modification treatment, a modified polypropylene adhesive is coated on the other side and then dried to form a modified polypropylene adhesive layer.

[0063] In a more specific embodiment, the modified polypropylene adhesive layer comprises modified polypropylene particles and a mixed solution, wherein the mass fraction of the modified polypropylene particles is 75-95%. Specifically, the mixed solution consists of 35-60% butanone and 40-65% cyclohexane by mass percentage. The modified polypropylene particles exist in the modified polypropylene adhesive layer in the form of polypropylene gel, which has a melt flow rate of 4.68, an acid value of 1.49, a melting point of 164-175°C, and a glass transition temperature of 135°C. The modified polypropylene adhesive layer also includes a curing agent, which has a mass fraction of 0.2-4% and is an epoxy resin.

[0064] S160. A modified polypropylene film is bonded to the surface of the modified polypropylene adhesive layer and subjected to secondary curing to form a second film layer; the heating temperature of the secondary curing is higher than the heating temperature of the primary curing.

[0065] Specifically, before the secondary curing, the process includes: heating and melting the modified polypropylene particles and then cooling them to obtain the modified polypropylene film, wherein the heating temperature for heating and melting is 180-230℃.

[0066] Modified polypropylene particles can be heated, melted, and then cooled to obtain a modified polypropylene film. Modification can be achieved by adding a modifier to the polypropylene. In this specific embodiment, ethylene propylene diene monomer (EPDM) resin is used as the modifier, and modified polypropylene particles containing polypropylene and EPDM resin are prepared by a dynamic phosphating method. The heating temperature for the modified polypropylene particles is 180-230℃, and the initial curing temperature can be 50-70℃.

[0067] In a specific embodiment, the heating temperature for the secondary curing is 60-85℃, and the heating time for the secondary curing increases with the increase of the heating temperature. Specifically, the heating temperature for the secondary curing is 60-70℃ and the heating time is 3-5 hours; or, the heating temperature for the secondary curing is 71-85℃ and the heating time is 20-40 hours.

[0068] More specifically, the heating temperature for secondary curing can be set to 60-85 degrees Celsius, and the heating time for secondary curing increases with increasing temperature. However, in practical applications, the heating time for secondary curing increases non-linearly with increasing temperature. The heating temperature for secondary curing can be 60-70℃, and the heating time can be 3-4 hours. For example, the heating temperature for secondary curing is 60℃ for 4 hours; the heating temperature for secondary curing is 70℃ for 4 hours; the heating temperature for secondary curing is 80℃ for 24 hours; and the heating temperature for secondary curing is 85℃ for 40 hours.

[0069] S170. After applying a lubricant to the surface of the second film layer, it is dried to form a lubricant layer.

[0070] Please see Figure 2 , Figure 2 This is a schematic cross-sectional view of the aluminum-plastic film provided in an embodiment of the present invention. The aluminum-plastic film prepared by the above processing method consists of a three-layer structure: a first film layer 1, a core layer 2, and a second film layer 3. The first film layer 1 comprises a nylon adhesive layer 12 and a nylon film layer 11 attached to the surface of the nylon adhesive layer 12. The second film layer 3 comprises a modified polypropylene adhesive layer 31 and a modified polypropylene polymer film layer 32 attached to the surface of the modified polypropylene adhesive layer 31. The modified polypropylene polymer film layer 32 can be a three-layer structure, with each layer composed of a modified polypropylene polymer film, and the thickness ratio of each layer in the three-layer structure is 1:8:1.

[0071] In a more specific embodiment, the surface of the second film layer 3 is further covered with a lubricant layer 4; the lubricant layer is composed of 25-80% erucamide and 20-75% ethanol by mass percentage.

[0072] The following comparison of multiple embodiments illustrates the specific implementation process and beneficial effects of the solution.

[0073] Example 1

[0074] An aluminum-plastic film, wherein the processing method is as follows:

[0075] After coating both sides of the aluminum foil with passivation solution, it is dried to obtain passivated aluminum foil.

[0076] After coating one side of the passivated aluminum foil with nylon adhesive and drying it, a nylon adhesive layer is formed; wherein the nylon adhesive layer is composed of 25% polyurethane resin, 45% isocyanate and 30% ethyl acetate by mass percentage.

[0077] A nylon film is bonded to the surface of the nylon adhesive layer and cured once to form a first film layer; wherein the heating temperature for the first curing is 55°C and the heating time is 3.5 hours.

[0078] The passivated aluminum foil containing the first film layer was subjected to low-temperature modification treatment in a chloroform solution at -38°C for 25 minutes; the chloroform solution also contained antioxidants and flame retardants. The antioxidant had a mass fraction of 0.8% and the flame retardant had a mass fraction of 1.5% in the chloroform solution.

[0079] After low-temperature modification, a modified polypropylene adhesive is coated onto the other side of a passivated aluminum foil and dried to form a modified polypropylene adhesive layer. The modified polypropylene adhesive layer comprises modified polypropylene particles and a mixed solution, wherein the modified polypropylene particles comprise 75% by mass; the mixed solution comprises 45% butanone and 55% cyclohexane by mass percentage. A curing agent, which is epoxy resin, is also added to the modified polypropylene adhesive layer, comprising 2.5% by mass.

[0080] A modified polypropylene film is bonded to the surface of the modified polypropylene adhesive layer and subjected to secondary curing to form a second film layer; the heating temperature of the secondary curing is higher than that of the primary curing; the temperature of the secondary curing is 70°C and the heating time is 4 hours.

[0081] Before secondary curing, the modified polypropylene particles are heated and melted and then cooled to obtain the modified polypropylene film. The heating temperature for heating and melting is 210°C.

[0082] After applying a lubricant to the surface of the second film layer and drying it, a lubricant layer is formed. The lubricant layer consists of 65% erucamide and 35% ethanol by mass percentage.

[0083] Example 2

[0084] After coating both sides of the aluminum foil with passivation solution, it is dried to obtain passivated aluminum foil.

[0085] After coating one side of the passivated aluminum foil with nylon adhesive and drying it, a nylon adhesive layer is formed; wherein the nylon adhesive layer is composed of 25% polyurethane resin, 45% isocyanate and 30% ethyl acetate by mass percentage.

[0086] A nylon film is bonded to the surface of the nylon adhesive layer and cured once to form a first film layer; wherein the heating temperature for the first curing is 55°C and the heating time is 3.5 hours.

[0087] The passivated aluminum foil containing the first film layer was subjected to low-temperature modification treatment in a chloroform solution at -45°C for 30 minutes; the chloroform solution also contained antioxidants and flame retardants. The antioxidant had a mass fraction of 0.8% and the flame retardant had a mass fraction of 1.5% in the chloroform solution.

[0088] After low-temperature modification, a modified polypropylene adhesive is coated onto the other side of a passivated aluminum foil and dried to form a modified polypropylene adhesive layer. The modified polypropylene adhesive layer comprises modified polypropylene particles and a mixed solution, wherein the modified polypropylene particles comprise 75% by mass; the mixed solution comprises 45% butanone and 55% cyclohexane by mass percentage. A curing agent, which is epoxy resin, is also added to the modified polypropylene adhesive layer, comprising 2.5% by mass.

[0089] A modified polypropylene film is bonded to the surface of the modified polypropylene adhesive layer and subjected to secondary curing to form a second film layer; the heating temperature of the secondary curing is higher than that of the primary curing; the temperature of the secondary curing is 70°C and the heating time is 4 hours.

[0090] Before secondary curing, the modified polypropylene particles are heated and melted and then cooled to obtain the modified polypropylene film. The heating temperature for heating and melting is 210°C.

[0091] After applying a lubricant to the surface of the second film layer and drying it, a lubricant layer is formed. The lubricant layer consists of 65% erucamide and 35% ethanol by mass percentage.

[0092] Example 3

[0093] After coating both sides of the aluminum foil with passivation solution, it is dried to obtain passivated aluminum foil.

[0094] After coating one side of the passivated aluminum foil with nylon adhesive and drying it, a nylon adhesive layer is formed; wherein the nylon adhesive layer is composed of 25% polyurethane resin, 45% isocyanate and 30% ethyl acetate by mass percentage.

[0095] A nylon film is bonded to the surface of the nylon adhesive layer and cured once to form a first film layer; wherein the heating temperature for the first curing is 65°C and the heating time is 3.5 hours.

[0096] The passivated aluminum foil containing the first film layer was subjected to low-temperature modification treatment in a chloroform solution at -38°C for 25 minutes; the chloroform solution also contained antioxidants and flame retardants. The antioxidant had a mass fraction of 0.8% and the flame retardant had a mass fraction of 1.5% in the chloroform solution.

[0097] After low-temperature modification, a modified polypropylene adhesive is coated onto the other side of a passivated aluminum foil and dried to form a modified polypropylene adhesive layer. The modified polypropylene adhesive layer comprises modified polypropylene particles and a mixed solution, wherein the modified polypropylene particles comprise 75% by mass; the mixed solution comprises 45% butanone and 55% cyclohexane by mass percentage. A curing agent, which is epoxy resin, is also added to the modified polypropylene adhesive layer, comprising 2.5% by mass.

[0098] A modified polypropylene film is bonded to the surface of the modified polypropylene adhesive layer and subjected to secondary curing to form a second film layer; the heating temperature of the secondary curing is higher than that of the primary curing; the temperature of the secondary curing is 70°C and the heating time is 4 hours.

[0099] Before secondary curing, the modified polypropylene particles are heated and melted and then cooled to obtain the modified polypropylene film. The heating temperature for heating and melting is 210°C.

[0100] After applying a lubricant to the surface of the second film layer and drying it, a lubricant layer is formed. The lubricant layer consists of 65% erucamide and 35% ethanol by mass percentage.

[0101] Example 4

[0102] An aluminum-plastic film, wherein the processing method is as follows:

[0103] After coating both sides of the aluminum foil with passivation solution, it is dried to obtain passivated aluminum foil.

[0104] After coating one side of the passivated aluminum foil with nylon adhesive and drying it, a nylon adhesive layer is formed; wherein the nylon adhesive layer is composed of 25% polyurethane resin, 45% isocyanate and 30% ethyl acetate by mass percentage.

[0105] A nylon film is bonded to the surface of the nylon adhesive layer and cured once to form a first film layer; wherein the heating temperature for the first curing is 65°C and the heating time is 3.5 hours.

[0106] The passivated aluminum foil containing the first film layer was subjected to low-temperature modification treatment in a chloroform solution at -45°C for 30 minutes; the chloroform solution also contained antioxidants and flame retardants. The antioxidant had a mass fraction of 0.8% and the flame retardant had a mass fraction of 1.5% in the chloroform solution.

[0107] After low-temperature modification, a modified polypropylene adhesive is coated onto the other side of a passivated aluminum foil and dried to form a modified polypropylene adhesive layer. The modified polypropylene adhesive layer comprises modified polypropylene particles and a mixed solution, wherein the modified polypropylene particles comprise 75% by mass; the mixed solution comprises 45% butanone and 55% cyclohexane by mass percentage. A curing agent, which is epoxy resin, is also added to the modified polypropylene adhesive layer, comprising 2.5% by mass.

[0108] A modified polypropylene film is bonded to the surface of the modified polypropylene adhesive layer and subjected to secondary curing to form a second film layer; the heating temperature of the secondary curing is higher than that of the primary curing; the temperature of the secondary curing is 70°C and the heating time is 4 hours.

[0109] Before secondary curing, the modified polypropylene particles are heated and melted and then cooled to obtain the modified polypropylene film. The heating temperature for heating and melting is 210°C.

[0110] After applying a lubricant to the surface of the second film layer and drying it, a lubricant layer is formed. The lubricant layer consists of 65% erucamide and 35% ethanol by mass percentage.

[0111] Example 5

[0112] An aluminum-plastic film, wherein the processing method is as follows:

[0113] After coating both sides of the aluminum foil with passivation solution, it is dried to obtain passivated aluminum foil.

[0114] After coating one side of the passivated aluminum foil with nylon adhesive and drying it, a nylon adhesive layer is formed; wherein the nylon adhesive layer is composed of 25% polyurethane resin, 45% isocyanate and 30% ethyl acetate by mass percentage.

[0115] A nylon film is bonded to the surface of the nylon adhesive layer and cured once to form a first film layer; wherein the heating temperature for the first curing is 65°C and the heating time is 3.5 hours.

[0116] The passivated aluminum foil containing the first film layer was subjected to low-temperature modification treatment in a chloroform solution at -45°C for 25 minutes; the chloroform solution also contained antioxidants and flame retardants. The antioxidant had a mass fraction of 0.8% and the flame retardant had a mass fraction of 1.5% in the chloroform solution.

[0117] After low-temperature modification, a modified polypropylene adhesive is coated onto the other side of a passivated aluminum foil and dried to form a modified polypropylene adhesive layer. The modified polypropylene adhesive layer comprises modified polypropylene particles and a mixed solution, wherein the modified polypropylene particles comprise 75% by mass; the mixed solution comprises 45% butanone and 55% cyclohexane by mass percentage. A curing agent, which is epoxy resin, is also added to the modified polypropylene adhesive layer, comprising 2.5% by mass.

[0118] A modified polypropylene film is bonded to the surface of the modified polypropylene adhesive layer and subjected to secondary curing to form a second film layer; the heating temperature of the secondary curing is higher than that of the primary curing; the temperature of the secondary curing is 70°C and the heating time is 4 hours.

[0119] Before secondary curing, the modified polypropylene particles are heated and melted and then cooled to obtain the modified polypropylene film. The heating temperature for heating and melting is 210°C.

[0120] After applying a lubricant to the surface of the second film layer and drying it, a lubricant layer is formed. The lubricant layer consists of 65% erucamide and 35% ethanol by mass percentage.

[0121] Example 6

[0122] An aluminum-plastic film, wherein the processing method is as follows:

[0123] After coating both sides of the aluminum foil with passivation solution, it is dried to obtain passivated aluminum foil.

[0124] After coating one side of the passivated aluminum foil with nylon adhesive and drying it, a nylon adhesive layer is formed; wherein the nylon adhesive layer is composed of 25% polyurethane resin, 45% isocyanate and 30% ethyl acetate by mass percentage.

[0125] A nylon film is bonded to the surface of the nylon adhesive layer and cured once to form a first film layer; wherein the heating temperature for the first curing is 55°C and the heating time is 3.5 hours.

[0126] The passivated aluminum foil containing the first film layer was subjected to low-temperature modification treatment in a chloroform solution at -38°C for 25 minutes; the chloroform solution also contained antioxidants and flame retardants. The antioxidant had a mass fraction of 0.8% and the flame retardant had a mass fraction of 1.5% in the chloroform solution.

[0127] After low-temperature modification, a modified polypropylene adhesive is coated onto the other side of a passivated aluminum foil and dried to form a modified polypropylene adhesive layer. The modified polypropylene adhesive layer comprises modified polypropylene particles and a mixed solution, wherein the modified polypropylene particles comprise 75% by mass; the mixed solution comprises 45% butanone and 55% cyclohexane by mass percentage. A curing agent, which is epoxy resin, is also added to the modified polypropylene adhesive layer, comprising 2.5% by mass.

[0128] A modified polypropylene film is bonded to the surface of the modified polypropylene adhesive layer and subjected to secondary curing to form a second film layer; the heating temperature of the secondary curing is higher than that of the primary curing; the temperature of the secondary curing is 82°C and the heating time is 36 hours.

[0129] Before secondary curing, the modified polypropylene particles are heated and melted and then cooled to obtain the modified polypropylene film. The heating temperature for heating and melting is 210°C.

[0130] After applying a lubricant to the surface of the second film layer and drying it, a lubricant layer is formed. The lubricant layer consists of 65% erucamide and 35% ethanol by mass percentage.

[0131] Example 7

[0132] After coating both sides of the aluminum foil with passivation solution, it is dried to obtain passivated aluminum foil.

[0133] After coating one side of the passivated aluminum foil with nylon adhesive and drying it, a nylon adhesive layer is formed; wherein the nylon adhesive layer is composed of 25% polyurethane resin, 45% isocyanate and 30% ethyl acetate by mass percentage.

[0134] A nylon film is bonded to the surface of the nylon adhesive layer and cured once to form a first film layer; wherein the heating temperature for the first curing is 55°C and the heating time is 3.5 hours.

[0135] The passivated aluminum foil containing the first film layer was subjected to low-temperature modification treatment in a chloroform solution at -45°C for 30 minutes; the chloroform solution also contained antioxidants and flame retardants. The antioxidant had a mass fraction of 0.8% and the flame retardant had a mass fraction of 1.5% in the chloroform solution.

[0136] After low-temperature modification, a modified polypropylene adhesive is coated onto the other side of a passivated aluminum foil and dried to form a modified polypropylene adhesive layer. The modified polypropylene adhesive layer comprises modified polypropylene particles and a mixed solution, wherein the modified polypropylene particles comprise 75% by mass; the mixed solution comprises 45% butanone and 55% cyclohexane by mass percentage. A curing agent, which is epoxy resin, is also added to the modified polypropylene adhesive layer, comprising 2.5% by mass.

[0137] A modified polypropylene film is bonded to the surface of the modified polypropylene adhesive layer and subjected to secondary curing to form a second film layer; the heating temperature of the secondary curing is higher than that of the primary curing; the temperature of the secondary curing is 82°C and the heating time is 36 hours.

[0138] Before secondary curing, the modified polypropylene particles are heated and melted and then cooled to obtain the modified polypropylene film. The heating temperature for heating and melting is 210°C.

[0139] After applying a lubricant to the surface of the second film layer and drying it, a lubricant layer is formed. The lubricant layer consists of 65% erucamide and 35% ethanol by mass percentage.

[0140] Example 8

[0141] After coating both sides of the aluminum foil with passivation solution, it is dried to obtain passivated aluminum foil.

[0142] After coating one side of the passivated aluminum foil with nylon adhesive and drying it, a nylon adhesive layer is formed; wherein the nylon adhesive layer is composed of 25% polyurethane resin, 45% isocyanate and 30% ethyl acetate by mass percentage.

[0143] A nylon film is bonded to the surface of the nylon adhesive layer and cured once to form a first film layer; wherein the heating temperature for the first curing is 65°C and the heating time is 3.5 hours.

[0144] The passivated aluminum foil containing the first film layer was subjected to low-temperature modification treatment in a chloroform solution at -38°C for 25 minutes; the chloroform solution also contained antioxidants and flame retardants. The antioxidant had a mass fraction of 0.8% and the flame retardant had a mass fraction of 1.5% in the chloroform solution.

[0145] After low-temperature modification, a modified polypropylene adhesive is coated onto the other side of a passivated aluminum foil and dried to form a modified polypropylene adhesive layer. The modified polypropylene adhesive layer comprises modified polypropylene particles and a mixed solution, wherein the modified polypropylene particles comprise 75% by mass; the mixed solution comprises 45% butanone and 55% cyclohexane by mass percentage. A curing agent, which is epoxy resin, is also added to the modified polypropylene adhesive layer, comprising 2.5% by mass.

[0146] A modified polypropylene film is bonded to the surface of the modified polypropylene adhesive layer and subjected to secondary curing to form a second film layer; the heating temperature of the secondary curing is higher than that of the primary curing; the temperature of the secondary curing is 82°C and the heating time is 36 hours.

[0147] Before secondary curing, the modified polypropylene particles are heated and melted and then cooled to obtain the modified polypropylene film. The heating temperature for heating and melting is 210°C.

[0148] After applying a lubricant to the surface of the second film layer and drying it, a lubricant layer is formed. The lubricant layer consists of 65% erucamide and 35% ethanol by mass percentage.

[0149] Example 9

[0150] An aluminum-plastic film, wherein the processing method is as follows:

[0151] After coating both sides of the aluminum foil with passivation solution, it is dried to obtain passivated aluminum foil.

[0152] After coating one side of the passivated aluminum foil with nylon adhesive and drying it, a nylon adhesive layer is formed; wherein the nylon adhesive layer is composed of 25% polyurethane resin, 45% isocyanate and 30% ethyl acetate by mass percentage.

[0153] A nylon film is bonded to the surface of the nylon adhesive layer and cured once to form a first film layer; wherein the heating temperature for the first curing is 65°C and the heating time is 3.5 hours.

[0154] The passivated aluminum foil containing the first film layer was subjected to low-temperature modification treatment in a chloroform solution at -45°C for 30 minutes; the chloroform solution also contained antioxidants and flame retardants. The antioxidant had a mass fraction of 0.8% and the flame retardant had a mass fraction of 1.5% in the chloroform solution.

[0155] After low-temperature modification, a modified polypropylene adhesive is coated onto the other side of a passivated aluminum foil and dried to form a modified polypropylene adhesive layer. The modified polypropylene adhesive layer comprises modified polypropylene particles and a mixed solution, wherein the modified polypropylene particles comprise 75% by mass; the mixed solution comprises 45% butanone and 55% cyclohexane by mass percentage. A curing agent, which is epoxy resin, is also added to the modified polypropylene adhesive layer, comprising 2.5% by mass.

[0156] A modified polypropylene film is bonded to the surface of the modified polypropylene adhesive layer and subjected to secondary curing to form a second film layer; the heating temperature of the secondary curing is higher than that of the primary curing; the temperature of the secondary curing is 82°C and the heating time is 36 hours.

[0157] Before secondary curing, the modified polypropylene particles are heated and melted and then cooled to obtain the modified polypropylene film. The heating temperature for heating and melting is 210°C.

[0158] After applying a lubricant to the surface of the second film layer and drying it, a lubricant layer is formed. The lubricant layer consists of 65% erucamide and 35% ethanol by mass percentage.

[0159] Example 10

[0160] An aluminum-plastic film, wherein the processing method is as follows:

[0161] After coating both sides of the aluminum foil with passivation solution, it is dried to obtain passivated aluminum foil.

[0162] After coating one side of the passivated aluminum foil with nylon adhesive and drying it, a nylon adhesive layer is formed; wherein the nylon adhesive layer is composed of 25% polyurethane resin, 45% isocyanate and 30% ethyl acetate by mass percentage.

[0163] A nylon film is bonded to the surface of the nylon adhesive layer and cured once to form a first film layer; wherein the heating temperature for the first curing is 65°C and the heating time is 3.5 hours.

[0164] The passivated aluminum foil containing the first film layer was subjected to low-temperature modification treatment in a chloroform solution at -45°C for 25 minutes; the chloroform solution also contained antioxidants and flame retardants. The antioxidant had a mass fraction of 0.8% and the flame retardant had a mass fraction of 1.5% in the chloroform solution.

[0165] After low-temperature modification, a modified polypropylene adhesive is coated onto the other side of a passivated aluminum foil and dried to form a modified polypropylene adhesive layer. The modified polypropylene adhesive layer comprises modified polypropylene particles and a mixed solution, wherein the modified polypropylene particles comprise 75% by mass; the mixed solution comprises 45% butanone and 55% cyclohexane by mass percentage. A curing agent, which is epoxy resin, is also added to the modified polypropylene adhesive layer, comprising 2.5% by mass.

[0166] A modified polypropylene film is bonded to the surface of the modified polypropylene adhesive layer and subjected to secondary curing to form a second film layer; the heating temperature of the secondary curing is higher than that of the primary curing; the temperature of the secondary curing is 82°C and the heating time is 36 hours.

[0167] Before secondary curing, the modified polypropylene particles are heated and melted and then cooled to obtain the modified polypropylene film. The heating temperature for heating and melting is 210°C.

[0168] After applying a lubricant to the surface of the second film layer and drying it, a lubricant layer is formed. The lubricant layer consists of 65% erucamide and 35% ethanol by mass percentage.

[0169] Comparative Example 1

[0170] An aluminum-plastic film, wherein the processing method is as follows:

[0171] After coating both sides of the aluminum foil with passivation solution, it is dried to obtain the passivated aluminum foil.

[0172] After coating one side of the passivated aluminum foil with nylon adhesive and drying it, a nylon adhesive layer is formed.

[0173] A nylon film is laminated onto the surface of the nylon adhesive layer to form the first film layer. A passivated aluminum foil containing the first film layer is placed in a chloroform solution at -45°C for low-temperature modification treatment for 25 minutes; the chloroform solution also contains antioxidants and flame retardants. The antioxidant has a mass fraction of 0.8% in the chloroform solution, and the flame retardant has a mass fraction of 1.5% in the chloroform solution.

[0174] The other side of the passivated aluminum foil is coated with modified polypropylene adhesive and then dried to form the modified polypropylene adhesive layer.

[0175] A modified polypropylene film is laminated onto the surface of the modified polypropylene adhesive layer to form the second film layer.

[0176] Comparative Example 2

[0177] An aluminum-plastic film, wherein the processing method is as follows:

[0178] After coating both sides of the aluminum foil with passivation solution, it is dried to obtain the passivated aluminum foil.

[0179] After coating one side of the passivated aluminum foil with nylon adhesive and drying it, the nylon adhesive layer is formed.

[0180] A nylon film is laminated onto the surface of the nylon adhesive layer and then cured once to form a first film layer. The curing temperature for the first curing is 65°C, and the curing time is 3.5 hours.

[0181] After the passivated aluminum foil has undergone a curing process, a modified polypropylene adhesive is applied to the other side and then dried to form the modified polypropylene adhesive layer.

[0182] A modified polypropylene film is bonded to the surface of the modified polypropylene adhesive layer and subjected to secondary curing to form a second film layer; the heating temperature of the secondary curing is higher than that of the primary curing; the temperature of the secondary curing is 70°C and the heating time is 4 hours.

[0183] After applying a lubricant to the surface of the second film layer and drying it, a lubricant layer is formed.

[0184] Comparative Example 3

[0185] An aluminum-plastic film, wherein the processing method is as follows:

[0186] After coating both sides of the aluminum foil with passivation solution, it is dried to obtain the passivated aluminum foil.

[0187] After coating one side of the passivated aluminum foil with nylon adhesive and drying it, the nylon adhesive layer is formed.

[0188] A nylon film is laminated onto the surface of the nylon adhesive layer and then cured once to form a first film layer. The curing temperature for the first curing is 65°C, and the curing time is 3.5 hours.

[0189] The passivated aluminum foil containing the first film layer was subjected to low-temperature modification treatment in a chloroform solution at -45°C for 25 minutes; the chloroform solution also contained antioxidants and flame retardants. The antioxidant had a mass fraction of 0.8% and the flame retardant had a mass fraction of 1.5% in the chloroform solution.

[0190] After the passivated aluminum foil has undergone low-temperature modification treatment, a modified polypropylene adhesive is coated on the other side and then dried to form the modified polypropylene adhesive layer.

[0191] A modified polypropylene film is laminated onto the surface of the modified polypropylene adhesive layer to form a second film layer.

[0192] After applying a lubricant to the surface of the second film layer and drying it, a lubricant layer is formed.

[0193] Test Example 1

[0194] Aluminum-plastic film puncture test: Puncture tests were conducted on the aluminum-plastic films obtained in Examples 1-10 of this invention. Films with a length of 20 cm and a cross-sectional area of ​​0.375 mm² were cut from each example and comparative example. 2 The aluminum-plastic film passed the puncture test with a cross-sectional area of ​​0.1 cm². 2 The needle was used for puncture, and the force applied to the needle and the deformation of the aluminum-plastic film were measured. The results are as follows: Figure 3 As shown.

[0195] Figure 3 The maximum force values ​​for puncturing the aluminum-plastic film in each embodiment are shown in Table 1. The statistical results in Table 1 show that the puncture force of the aluminum-plastic film processed using the technical method in this application is all above 25.1N, with the maximum puncture force at 26.19N. In practical applications, it exhibits strong puncture resistance.

[0196] Table 1

[0197] Serial Number 1 2 3 4 5 6 7 8 9 10 Maximum force (N) 26.11 25.22 25.29 25.15 26.19 25.24 25.52 25.52 25.27 25.67

[0198] Test Example 2

[0199] Aluminum-plastic film tensile test: Tensile tests were performed on the aluminum-plastic films obtained in Examples 1-10 and Comparative Examples 2 and 3 of this invention. The cross-sectional area obtained from each example and comparative example was 1.695 mm². 2 The test curve obtained using an aluminum-plastic film with a length of 25cm is shown below. Figure 4 As shown, transverse and longitudinal tensile tests were performed on Examples 1, 5, Comparative Example 2, and Comparative Example 3. The tensile test speed was 25 mm / min. Transverse tensile testing was performed along the production and processing direction of the aluminum-plastic film, and the maximum tensile force, breaking strength, and breaking elongation were measured. The tensile strength was measured simultaneously during the tensile process. Longitudinal tensile testing was performed along the direction perpendicular to the production and processing direction of the aluminum-plastic film. The statistical results are shown in Table 2.

[0200] Table 2

[0201]

[0202] The aluminum-plastic film processed using the technical methods in this application exhibits strong stretchability in both the transverse and longitudinal directions, with a maximum longitudinal stretch rate of 149.4% and a maximum transverse stretch rate of 109.951%. The aluminum-plastic film corresponding to Example 5 shows the best test results. In contrast, the longitudinal and transverse stretch rates of the aluminum-plastic film in Comparative Example 3 are significantly different from those of the aluminum-plastic film in the examples, while the longitudinal and transverse stretch rates of the aluminum-plastic film in Comparative Example 2 are essentially close to those of the aluminum-plastic film in the examples. Therefore, the aluminum-plastic film processed using the technical methods of this application possesses excellent sealing strength in practical applications.

[0203] Test Example 3

[0204] Combustion test of aluminum-plastic film: Combustion tests were conducted on the aluminum-plastic films obtained in Examples 1-10 and Comparative Examples 1-3 of the present invention. A 20cm×20cm piece of aluminum-plastic film was cut from each example and comparative example. The first layer of each aluminum-plastic film was heated in an oxygen-containing environment (the oxygen concentration in the oxygen-containing environment was equal to the oxygen concentration in the atmosphere) until the first layer of film ignited. Hot air was blown into the first layer through a hot air gun with a gradually increasing airflow rate of 500L / min. The initial combustion temperature of each aluminum-plastic film was recorded. The statistical results are shown in Table 3. The initial combustion temperature can be used to prove the flame retardant properties of the material. The higher the initial combustion temperature, the stronger the flame retardant properties of the material.

[0205] Table 3

[0206]

[0207] The aluminum-plastic film processed using the technical method in this application has a significantly higher initial combustion temperature than the aluminum-plastic film processed in Comparative Example 2, and slightly higher than the aluminum-plastic films processed in Comparative Examples 1 and 3. Therefore, the aluminum-plastic film processed by the technical method of this application has better flame retardancy than the aluminum-plastic film processed by existing technical methods in practical applications.

[0208] The secondary curing aluminum-plastic film processing method provided in this embodiment of the invention includes the following steps: coating both sides of an aluminum foil with a passivation solution and drying it to obtain a passivated aluminum foil; coating one side of the passivated aluminum foil with a nylon adhesive and drying it to form a nylon adhesive layer; bonding the surface of the nylon adhesive layer with a nylon film and performing a first curing, then placing it in a chloroform solution for low-temperature modification treatment; coating the other side of the passivated aluminum foil with a modified polypropylene adhesive and drying it, then bonding the modified polypropylene film with it and performing a second curing; and coating the surface of the second film layer with a lubricant and drying it. In the above processing method, the core layer is a passivated aluminum foil, the modified polypropylene polymer film layer is attached to the surface of the core layer through a modified polypropylene adhesive layer, and the nylon film layer is attached to the surface of the core layer through a nylon adhesive layer and subjected to low-temperature modification treatment; combined with the two heating curing processes, the sealing strength and puncture strength of the processed aluminum-plastic film are improved, significantly enhancing the reliability of the aluminum-plastic film used in lithium battery products.

[0209] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for processing aluminum-plastic film through secondary curing, characterized in that, The processing method includes the following steps: After coating both sides of the aluminum foil with passivation solution, it is dried to obtain passivated aluminum foil; After coating one side of the passivated aluminum foil with nylon adhesive and drying it, a nylon adhesive layer is formed. A nylon film is bonded to the surface of the nylon adhesive layer and cured once to form a first film layer; The passivated aluminum foil containing the first film layer is placed in an organic solvent at -45°C to -35°C for low-temperature modification treatment for 15-35 minutes; the organic solvent also contains antioxidants and flame retardants. After low-temperature modification, the other side of the passivated aluminum foil is coated with modified polypropylene adhesive and then dried to form a modified polypropylene adhesive layer. A modified polypropylene film is laminated onto the surface of the modified polypropylene adhesive layer and subjected to secondary curing to form a second film layer; the heating temperature of the secondary curing is higher than that of the primary curing. After applying a lubricant to the surface of the second film layer and drying it, a lubricant layer is formed.

2. The method for secondary curing of aluminum-plastic film according to claim 1, characterized in that, Before the modified polypropylene film is bonded to the surface of the modified polypropylene adhesive layer and subjected to secondary curing, the process further includes: The modified polypropylene particles are heated and melted, and then cooled to obtain the modified polypropylene film. The heating temperature for heating and melting is 180-230℃.

3. The method for secondary curing of aluminum-plastic film according to claim 1, characterized in that, The heating temperature for the first curing is 50-70℃.

4. The method for secondary curing of aluminum-plastic film according to claim 3, characterized in that, The heating temperature for the secondary curing is 60-85℃, and the heating time for the secondary curing increases with the increase of the heating temperature.

5. The method for secondary curing of aluminum-plastic film according to claim 3, characterized in that, The heating temperature for the secondary curing is 60-70℃ and the heating time is 3-5 hours; Alternatively, the heating temperature for the secondary curing is 71-85℃ and the heating time is 20-40 hours.

6. The method for secondary curing of aluminum-plastic film according to claim 4 or 5, characterized in that, The modified polypropylene adhesive layer includes a curing agent, and the mass fraction of the curing agent in the modified polypropylene adhesive layer is 0.2-4%.

7. The method for secondary curing of aluminum-plastic film according to claim 4 or 5, characterized in that, The surface of the second film layer is further covered with a lubricant layer; the lubricant layer is composed of 25-80% erucamide and 20-75% ethanol by mass percentage.

8. The method for secondary curing of aluminum-plastic film according to claim 4 or 5, characterized in that, The modified polypropylene adhesive layer comprises modified polypropylene particles and a mixed solution, wherein the mass fraction of the modified polypropylene particles is 75-95%; and the mixed solution is composed of 35-60% butanone and 40-65% cyclohexane by mass percentage.

9. The method for secondary curing of aluminum-plastic film according to claim 4 or 5, characterized in that, The antioxidant has a mass fraction of 0.2-1.5% in the organic solvent.

10. The method for secondary curing of aluminum-plastic film according to claim 4 or 5, characterized in that, The flame retardant has a mass fraction of 0.5-2% in the organic solvent.

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