Primer layer composition, secondary battery pouch film using same, and method for manufacturing same

Abstract

To provide a secondary battery pouch film using a primer layer which is excellent in initial peel strength, hydrofluoric acid resistance, electrolyte resistance and the like, and particularly excellent in moldability.SOLUTION: A secondary battery pouch film comprising a primer layer interposed between a metallic layer and a melt-extruded resin layer or a sealant layer, wherein the formability is 6.5 mm or more and the initial peel strength is 14.0N / 15 mm or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a primer layer composition, a secondary battery pouch film using the same, and a method for producing the same. More specifically, the initial peel strength, hydrofluoric acid resistance, electrolyte resistance, etc., as well as the composition Primer layer composition with particularly improved formability, secondary battery pouch film using the same, and This relates to a method for producing the above.

[0002] [National research and development project supporting this invention] [Project number] 20007148 [Department name] Ministry of Trade, Industry and Energy [Name of issue management (specialized organization)] Korea Institute for Industrial Technology Evaluation and Management [Research Project Name] Material and Parts Technology Development - Material and Parts Package Type [Research title] Performance evaluation of medium- to large-sized secondary battery pouches and demonstration research on their application to consumer businesses [Contribution rate] 1 / 1 [Name of project executing organization] Yulchon Chemical Co., Ltd. [Research Period] 2019.09.01~2021.02.28 [Background technology]

[0003] Lithium secondary batteries (LiB) have a wide range of applications, including high energy density and excellent output. Based on these advantages, it has been applied to many applications.

[0004] The secondary battery pouch is an exterior material that covers the electrode group and electrolyte of the secondary battery, and is made of a metal thin film and Adhesion strength between polymer layers, heat fusion strength, electrolyte resistance, airtightness, moisture permeability, moldability, etc. Which required characteristics must be met?

[0005] The secondary battery pouch is roughly composed of an outer layer, a barrier layer, and an inner sealant layer. Usually, the outer or outermost layer is made of nylon or nylon and PET (polyethylene terephthalate). It is made up of a mixture of polyethylene (OPP), oriented polypropylene (OPP), and polyethylene. The required properties of such an outer layer or outermost layer are heat resistance, pinhole resistance, and chemical resistance. , moldability, and insulating properties are required.

[0006] The barrier layer is required to have barrier properties against water vapor and other gases as well as moldability. From this viewpoint, the barrier layer is preferably made of a moldable metal, such as aluminum (Al). Iron (Fe), copper (Cu), nickel (Ni), etc. are used, and currently aluminum is the most popular. It is used frequently.

[0007] The inner sealant layer has thermal adhesiveness and formability, and is resistant to the electrolyte because it is the layer that comes into contact with the electrolyte. Electrolytic properties and insulation resistance are required.

[0008] In particular, the application field of lithium-ion batteries is expanding from small areas to medium and large areas such as automobiles. Among these, properties suitable for medium to large sizes, such as resistance to hydrofluoric acid, resistance to electrolyte, and formability, are required. will be done. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent No. 4899235 Summary of the Invention [Problem to be solved by the invention]

[0010] In one aspect, the present invention provides a coating having high initial peel strength, high resistance to hydrofluoric acid, and high resistance to electrolyte. Primer layer composition having excellent moldability and excellent properties, and secondary battery pouch using the same The object is to provide a film and a method for producing the same. [Means for solving the problem]

[0011] In an exemplary embodiment of the present invention, at least an outer layer, a metal layer, a primer layer, and a sealant layer may be provided. or at least an outer layer, a metal layer, a primer layer, a melt-extruded resin layer, and a sealant layer. A method for producing a secondary battery pouch film, comprising the steps of: and a drying step of applying the primer layer composition to the substrate and heating the applied primer layer composition to dry and at least partially cure the primer layer composition. an organic solvent-based emulsion composition is used as the primer layer composition, The emulsion composition contains an acid-modified polypropylene and a curing agent, and has a curing initiation temperature of The temperature is 150°C or less, preferably 135°C to 150°C, and the drying process temperature is 150 ° C. or less, preferably 135 to 150 ° C., and the production method includes the step of attaching the sealant layer. A secondary battery pouch film characterized in that no thermal lamination process is performed when joining the two. A method of manufacture is provided.

[0012] In an exemplary embodiment of the present invention, at least an outer layer, a metal layer, a primer layer, and a sealant layer may be provided. or at least an outer layer, a metal layer, a primer layer, a melt-extruded resin layer, and a sealant layer. A method for improving the formability of a secondary battery pouch film, comprising the steps of: Drying the composition by applying and heating the primer layer composition to dry and at least partially cure it. a step of using an organic solvent-based emulsion composition as the primer layer composition, The organic solvent-based emulsion composition comprises an acid-modified polypropylene and a curing agent, and The starting temperature is 150°C or less, preferably 135°C to 150°C, and the drying process temperature is The temperature is 150°C or less, preferably 135°C to 150°C, and the method includes the step of applying a sealant layer. A secondary battery pouch film characterized by not requiring a thermal lamination process when it is bonded together. The present invention provides a method for improving the formability of a molded article.

[0013] In an exemplary embodiment of the present invention, a secondary battery pouch film used in the manufacturing method is also A primer layer composition sandwiched between the metal layer and the melt-extruded resin layer or sealant layer. The primer layer is formed from an organic solvent-based emulsion composition, and the organic solvent-based The emulsion composition contains an acid-modified polypropylene and a curing agent, and has a curing initiation temperature of 150°C or less, preferably 135°C to 150°C, and the drying process temperature is 150°C or less. Preferably, the temperature is 135°C to 150°C. A primer layer composition for use in a coating is provided.

[0014] In an example embodiment of the present invention, there is further provided a secondary battery pouch film, which is fused with a metal layer. a primer layer sandwiched between the melt-extruded resin layer or the sealant layer, is formed from an organic solvent-based emulsion composition, and the organic solvent-based emulsion composition is It contains an acid-modified polypropylene and a curing agent, and has a curing initiation temperature of 150°C or less, preferably The drying temperature is 135°C to 150°C, and the drying temperature is 150°C or less, preferably 135°C The present invention provides a secondary battery pouch film characterized by having a temperature of 100 to 150°C.

[0015] In addition, in an example embodiment of the present invention, the secondary battery pouch film may further include a metal and a primer layer sandwiched between the melt-extruded resin layer or the sealant layer, 0.5mm or more, initial peel strength is 14.0N / 15mm or more, and hydrofluoric acid resistance is 5.0N / 15mm or more, and the electrolyte resistance strength is 90% or more of the initial peel strength. Provides secondary battery pouch film. [Effects of the Invention]

[0016] In an exemplary embodiment of the present invention, a metal layer and a melt extrusion are used in the manufacture of a secondary battery pouch film. The primer layer composition sandwiched between the resin layer or sealant layer is an acid-modified polypropylene. A two-component curing type organic solvent-based emulsion composition containing ethylene and a curing agent is used to initiate curing. By adjusting the initial temperature and drying process temperature and not applying heat lamination, the initial peel strength is In addition to the hydrofluoric acid resistance and electrolyte resistance, the material has excellent moldability. can. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a schematic diagram illustrating the structure of a pouch film for a secondary battery according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] <Terminology> In this specification, when each layer of a secondary battery pouch film is included in order, it does not necessarily mean that the layers are included in order. It does not have to be composed of only this, but may further include other layers.

[0019] In this specification, "formed on" a metal layer does not mean that the metal layer is formed directly on the metal layer. It also includes the case where the insulating layer is formed through another layer such as a corrosion prevention layer.

[0020] In this specification, the term "cure initiation temperature" refers to the temperature at which the curing reaction starts.

[0021] In this specification, the drying step refers to the drying of the emulsion composition of the primer layer. The process for evaporating the liquid agent to be applied and accelerating the curing reaction of the emulsion composition of the primer layer is performed. This drying step is carried out before the lamination of the sealant layer. Therefore, it is different from the thermal lamination process.

[0022] In this specification, the drying temperature refers to the temperature at which the emulsion composition of the primer layer is dried. To evaporate the liquid used and promote the curing reaction of the emulsion composition of the primer layer This refers to the temperature in the process and refers to the maximum set temperature.

[0023] In this specification, the thermal lamination process refers to a process in which a primer layer is formed on a metal layer and a sealant is applied. When laminating the metal layer with the primer layer or after forming the primer layer and the melt-extruded resin layer on the metal layer, When laminating the primer layer, the curing reaction of the emulsion composition of the primer layer is further accelerated. This refers to the process of heating and laminating to achieve the desired effect.

[0024] In this specification, a thermal lamination process is used to bond (laminate) the sealant layer. By unapplied, it is meant that the lamination is applied only with pressure and without the application of heat.

[0025] In this specification, formability refers to the ability to mold a sample made of a secondary battery pouch film in a mold. This means that the molding depth is such that 10 or more samples do not break during molding. When the thickness is m or more, the moldability is excellent.

[0026] In this specification, the method for improving the formability of a secondary battery pouch film is to improve the initial peel strength, peel resistance, The properties such as fluorine acid resistance and electrolyte resistance exceed the required level, and the formability is improved to 6.5 mm or more. It means how to do something.

[0027] The electrolyte resistance strength is considered to be suitable when it is 90% or more of the initial peel strength. The strength against hydrofluoric acid must be 5N / 15mm or more. Acid strength is greatly affected by the initial peel strength, so the initial peel strength should be 14N / 15mm or more. It is preferable to do so.

[0028] <Description of Illustrative Embodiments> Hereinafter, exemplary embodiments of the present invention will be described in detail.

[0029] FIG. 1 is a schematic diagram showing the structure of a secondary battery pouch film according to an exemplary embodiment of the present invention. be.

[0030] As shown in FIG. 1, the secondary battery pouch film according to the exemplary embodiment of the present invention has at least The laminated laminated film may include an outer layer, a metal layer, a primer layer, and a sealant layer in this order, or at least The secondary layer includes an outer layer, a metal layer, a primer layer, a melt-extruded resin layer, and a sealant layer in this order. This is a battery pouch film.

[0031] The organic solvent-based emulsion used in the primer layer is liquid and does not require a separate coating. It can be formed on the metal layer through a sealing process. Or, when a melt-extruded resin layer is sandwiched, the adhesiveness and density of the melt-extruded resin layer and the sealant layer may be deteriorated. To improve adhesion, two process steps are generally used.

[0032] First, in the first process step, the liquid agent used as the emulsion solvent is evaporated to form a hardened emulsion. A drying process is carried out to accelerate the curing reaction, and then the sealant layer is attached in the second process. When laminating the sealant layer after forming the melt-extruded resin layer, a ply is further added. A thermal lamination process in which lamination is performed under heat to accelerate the curing reaction of the composition of the mer layer. Apply.

[0033] The thermal lamination process directly applies high temperature to the secondary battery pouch, so a lot of heat is transferred. This is a very useful process for accelerating the emulsion curing reaction. However, the present inventors have found that the secondary battery pouch is directly exposed to high temperatures during the thermal lamination process. This may reduce the slipperiness of the sealant layer and deteriorate moldability. I confirmed that.

[0034] Therefore, in an exemplary embodiment of the present invention, at least an outer layer, a metal layer, a primer layer, a sheet The laminate may include, in this order, at least an outer layer, a metal layer, a primer layer, a melt-extruded A method for manufacturing a secondary battery pouch film including a resin layer and a sealant layer in this order, or a method for manufacturing a secondary battery pouch film including a resin layer and a sealant layer in this order As a method for improving the formability of battery pouch film, we have developed a method for making the film without the thermal lamination process mentioned above. Only the drying process is carried out. In addition, the metal layer of the secondary battery pouch film and the melt-extruded resin layer or the metal The primer layer composition sandwiched between the primer layer and the sealant layer is, for example, an acid-modified polypropylene. It is composed of a two-component curing type organic solvent-based emulsion composition containing a resin and a curing agent. In addition, the curing start temperature and drying process temperature are adjusted. This improves the initial peel strength, hydrofluoric acid resistance, In addition to the electrolyte resistance, the composition has the effect of being particularly excellent in formability.

[0035] First, we will explain the organic solvent-based emulsion composition. They are divided into two types: acid-modified polypropylene and organic solvent-based polymers. When water is used as the solvent for the emulsion containing Organic solvents (cyclohexane (CH), ethyl acetate (EA), toluene (TOL), etc.) When used, it is called an organic solvent type.

[0036] In an exemplary embodiment of the present invention, the primer layer composition may be an organic solvent-based emulsion composition. Preferably, a two-component curing type organic solvent-based emulsion composition is used. The organic solvent-based emulsion composition of the type is, for example, a composition in which acid-modified polypropylene is dissolved in an organic solvent. The first solution (main part) is made by dissolving a curing agent in an organic solvent, and the second solution (hardening agent) is made by dissolving a curing agent in an organic solvent. It consists of two parts:

[0037] This two-component curing organic solvent emulsion is mixed to form a sealant between the metal layer and the sealant. The layer, or preferably the melt-extruded polypropylene layer and the metal layer, are laminated together.

[0038] Between the metal layer and the sealant layer, or preferably between the melt-extruded polypropylene layer and the metal layer The organic solvent-based emulsion layer, preferably a two-component curing type organic solvent-based emulsion layer, is disposed between the By forming an emulsion layer and controlling the drying and hardening, the inner shell of the secondary battery pouch film can be formed. It provides adhesive strength between the grease layer and the metal layer and also improves resistance to hydrofluoric acid and electrolyte. In addition, the aforementioned formability can also be improved.

[0039] Incidentally, when a primer layer is formed using a water-based emulsion, the process temperature is relatively It can be set to a low temperature (around 100°C), but has the disadvantage of being poorly resistant to hydrofluoric acid. On the other hand, when an organic solvent-based emulsion is used, it is very resistant to hydrofluoric acid, but the emulsion To accelerate the reaction in the emulsion, the process temperature is set high (150°C or higher) or a separate However, the higher the process temperature, the more the sealant This has the drawback of reducing the slippage between the first layer and the outer layer, resulting in poor formability.

[0040] In an example embodiment, the two-component curing type is classified according to the type of curing agent, and is amine Various types such as those based on acid anhydrides, polyamides, etc. may be used.

[0041] In an exemplary embodiment, the acid-modified polypropylene is a polypropylene containing acetic anhydride, glutaric acid or the like. Modified with various acid anhydrides such as benzoic anhydride, phthalic anhydride, and maleic anhydride It may be something that has been done.

[0042] In an exemplary embodiment, the curing agent may be an epoxy-based, acrylic-based, or urethane-based curing agent. The curing agent may be a two-component curing agent, preferably an epoxy curing agent. This can improve the electrolyte resistance and hydrofluoric acid resistance.

[0043] For example, epoxy-based two-component curing types undergo a curing reaction with carboxylic acid and acid anhydride. A curing reaction occurs, and the metal layer and the sealant layer are bonded together. Incidentally, acid anhydrides and epoxy curing agents generally undergo a curing reaction at high temperatures of 200°C or higher. It is said that the curing starts at a temperature of 200°C. Therefore, the starting temperature must be lowered by a catalyst.

[0044] In one exemplary embodiment, for example, a two-component curing type organic solvent-based emulsion may be Contains additives such as acid-modified polypropylene, ammonium salt, and 2,5-flazione. A first solution (main part) made by dissolving a main substance containing the epoxy resin in an organic solvent, and an epoxy-based hardener. A curing agent material containing an ether polymer (which may further contain other additives) is dissolved in an organic solvent. The second solution (hardener part) may be, but is not limited to, the following:

[0045] Incidentally, in the first solution, the acid-modified polypropylene adheres to the metal surface and is bonded. It plays a role in improving the adhesive strength between the sealant layer or melt-extruded resin layer and polypropylene. Other additives may also play a role in improving the chemical stability of the emulsion.

[0046] On the other hand, in the second solution, the ether polymerization agent forms an emulsion that adheres to the metal surface. Depending on the application, metal surface / emulsion / polypropylene layer (polypropylene layer of sealant layer or The adhesive layer forms a chemical bond between the melt-extruded resin layer and the polypropylene layer, thereby realizing adhesiveness. In addition, the stability of the second solution, the high temperature stability after the curing reaction, and the resistance to hydrofluoric acid can be improved. As the ether polymer, bisphenol A-bisphenol A diglycidyl ether polymer of methyl methacrylate may be used as a derivative to induce epoxy bonding. It's okay to stay.

[0047] Meanwhile, in an example embodiment, the curing initiation temperature is 150°C or less, preferably 1 Bring the temperature to 35-150°C.

[0048] By having such a curing initiation temperature, the drying process temperature can be lowered and the fluorine resistance can be improved. The resulting product has excellent properties such as acid resistance, electrolyte resistance, and moldability.

[0049] That is, in order for the metal layer and the sealant layer to be bonded, the primer layer must be formed. The curing reaction of the adhesive must be sufficient. Since it plays an extremely important role in determining the electrolyte resistance, it must have excellent thermal properties and be chemically stable. Generally, thermosetting resins are used because they have these properties.

[0050] However, the curing reaction may start at a high temperature, and the curing reaction may not proceed satisfactorily. If this is not done, the adhesiveness will deteriorate, which will affect the resistance to hydrofluoric acid and electrolyte. For these reasons, when the high-temperature thermal lamination process described above is carried out, There is a drawback in that the formability of the secondary battery pouch film is decisively deteriorated depending on the process.

[0051] That is, the outer layer of the secondary battery pouch film and the seal are bonded through a high-temperature thermal lamination process. The slippage between the resin and the land layer may decrease, resulting in poor formability. The lamination process may increase the hardness of the adhesive and primer layers on the outer layer. However, as the hardness increases, the elasticity of the secondary battery pouch film decreases, and As a result, moldability may deteriorate.

[0052] Therefore, it is effective to lower the initiation temperature so that the curing reaction can proceed sufficiently at a low process temperature. From this viewpoint, the curing start temperature is set to 150°C or less, or 135 to 150°C. Make it so that it becomes like this.

[0053] Here, the initiation temperature can be lowered by adding a catalyst, but it is not possible to lower it significantly. It is difficult to reduce the activation energy of a chemical reaction. It is a substance that does not participate in the reaction, and even if the amount added increases, the decrease in activation energy is not proportional to In addition, since the catalyst remains without participating in the reaction, if used in large amounts, it may have a negative effect on the physical properties. Therefore, there is a limit to how much the starting temperature can be lowered. It is difficult to lower the starting temperature.

[0054] In an exemplary embodiment, a catalyst for lowering the initiation temperature and accelerating the curing reaction may be Generally, tertiary amines (trimethylamine, triethylamine, N,N-dimethylpropane) Tertiary amines, in particular, have excellent adhesive properties with metals. The tertiary amine plays a role in promoting the reaction between the acid anhydride and the epoxy, which improves the efficiency of the reaction. The tertiary amine may react with the epoxy to produce a tertiary amine, and the produced tertiary amine may act as a catalyst. .

[0055] On the other hand, the temperature in the drying step is set to 100 to 150°C, preferably 135 to 150°C. If the drying temperature exceeds 150°C, moldability will decrease, as will be seen in the experimental example described later. It becomes possible.

[0056] In other words, if the drying temperature is high, the hardening reaction of the two-component hardening adhesive is accelerated, and the adhesive strength is increased. However, it reduces the slippage between the outer layer and the sealant layer, resulting in poor formability. On the other hand, if the drying temperature is low, the curing reaction of the two-component curing adhesive may not proceed sufficiently. To solve this problem, a separate high-temperature thermal lamination process is used as described above. If a further molding step is carried out, the slip properties and moldability may be reduced during this process.

[0057] In one exemplary embodiment, during the drying process of the emulsion, the drying process zone is divided into stages. It is preferable from the viewpoint of moldability to set the temperature so as to increase and decrease stepwise.

[0058] For example, in the drying process, the drying process zone is divided into a plurality of zones, and the set temperature of the first zone is The set temperature of the area between the first and last area is set higher than the set temperature of the last area. It is preferable to set the thickness at a low value from the viewpoint of moldability.

[0059] In a non-limiting example, the drying process may be divided into a minimum of 3 zones and a maximum of 15 zones. The temperature of each zone may be set, with the temperature of the middle zone being set the highest. The temperature will be the highest temperature set for each zone.

[0060] In an exemplary embodiment, initial peel strength, electrolyte resistance strength, hydrofluoric acid resistance strength, and puncture strength When considering moldability as well, the curing reaction starting temperature is 135 to 150°C. It is most preferable that the drying temperature is 135 to 150°C.

[0061] In an exemplary embodiment, the manufacturing method includes the step of attaching a sealant layer after the drying step. When the primer layer is combined with the emulsion composition, the emulsion composition is cured completely. The resulting product may be subjected to an aging step at room temperature.

[0062] Meanwhile, in an exemplary embodiment of the present invention, a secondary battery pouch filler is used in the manufacturing method. A primer layer composition sandwiched between a metal layer and a melt-extruded resin layer or a sealant layer. The primer layer composition is formed from an organic solvent-based emulsion composition, The organic solvent-based emulsion composition is a two-component curing type containing acid-modified polypropylene and a curing agent. It is characterized by having a curing start temperature of 150°C or less and being dried at 150°C or less. The present invention provides a primer layer composition for a secondary battery pouch film.

[0063] In addition, in an exemplary embodiment of the present invention, there is further provided a secondary battery pack manufactured by the manufacturing method. A plastic film sandwiched between a metal layer and a melt-extruded resin layer or a sealant layer. It contains a rubber layer, has a formability of 6.5 mm or more, and an initial peel strength of 14.0 N / 15 mm. The hydrofluoric acid resistance strength is 5.0N / 15mm or more, and the electrolyte resistance strength is the initial peel strength. We provide a secondary battery pouch film with a resistance of 90% or more.

[0064] In one exemplary embodiment, the initial peel strength is 14.0 N / 15 mm or more, and the electrolytic resistance is Liquid strength is 14.0N / 15mm or more, and hydrofluoric acid resistance is 5.0N / 15mm or more. The puncture strength may be 21.0 N or more.

[0065] In one exemplary embodiment, the moldability is 6.5 to 6.8 mm, and the initial peel strength is 14 0.0~15.0N / 15mm, and electrolyte resistance strength is 14.0~14.5N / 15mm. The hydrofluoric acid resistance strength is 6.0 to 6.4 N / 15 mm, and the puncture strength is 21.0 to 23 It can be .0N.

[0066] Referring again to FIG. 1, in one exemplary embodiment, the secondary battery pouch film may include: In particular, the substrate layer, the metal layer, and the corrosion prevention layer (acid-resistant layer) formed on at least one side of the metal layer a coating layer), a primer layer formed on the inside of the metal layer, and a polypropylene melt-extruded resin layer. It consists of a pyrene extrusion layer and a non-oriented polypropylene (CPP) layer as a sealant layer. stomach.

[0067] The substrate layer is made of at least one of a polyester film and a polyimide film. For example, the outermost layer may be a polyethylene terephthalate (PET) film, The inner surface may be made of a nylon film. Dry lamination (Solvent Dry Lamination) is performed via the first adhesive layer. The nylon film and metal layer can be bonded together by applying SDL (Stiction Layer Deposition). Dry lamination (Solvent Dry Lamination) through a second adhesive layer on;SDL) and then glue them together.

[0068] The metal layer may be made of aluminum, which is typically used. As a corrosion prevention layer, a chromate-based or non-chromate-based aluminum corrosion prevention layer is formed. It can be achieved.

[0069] The unstretched polypropylene layer of the sealant layer may be formed in multiple layers, for example, three layers. [Example]

[0070] Illustrative embodiments of the present invention will be described in more detail through the following examples. The illustrated embodiments are merely for illustrative purposes and may be embodied in various forms. The present invention should not be construed as being limited to the examples set forth herein. stomach.

[0071] [Experiment 1: Comparative experiment using different curing reaction initiation temperatures and drying process temperatures] As shown in Figure 1, when manufacturing a secondary battery pouch, the base layer (PET / nylon) and A First, the aluminum metal layer on which the corrosion prevention layer is formed is bonded, and then in the final step, the substrate layer and the metal A sealant is applied to the base film, which is made by laminating an aluminum metal layer with an aluminum corrosion prevention layer. When laminating the sealant layer, the ply was attached to the metal layer. To form a liner layer, emulsion coating and drying processes are carried out, followed by a sealant. The secondary battery pouch film was fabricated by laminating the sealant layer. During the extrusion, polypropylene may be further extruded to form a melt-extruded resin layer.

[0072] As mentioned above, during the emulsion drying process, the temperature is increased in stages in separate zones. Set the temperature to decrease, and divide the temperature into a minimum of 3 zones and a maximum of 15 zones. In this experiment 1, the room was divided into 10 zones as an example. The temperature of the middle zone was set to the highest. The process temperature indicates the highest temperature among the set temperatures.

[0073] A two-component organic solvent emulsion applied to the primer layer of secondary battery pouch film. John was made based on bisphenol A epoxy type. This is the most typical type and is characterized by its excellent adhesiveness, chemical resistance, and high-temperature properties.

[0074] A first polymer obtained by dissolving a base material containing the acid-modified polypropylene described above in an organic solvent. The solution (main part) and the hardener material containing epoxy hardener and ether polymer are mixed in an organic solvent. A second solution (hardener part) prepared by dissolving the hardener in the above may be used, but is not limited thereto. do not have.

[0075] As mentioned above, in order to lower the curing reaction initiation temperature (hereinafter referred to as the initiation temperature) and promote the curing reaction, Generally, tertiary amines and imidazoles can be used as catalysts for this purpose. A tertiary amine was used as an example.

[0076] The comparative examples and examples are summarized below.

[0077] (Comparative Example 1) A two-component solvent-based emulsion with an initial temperature of 175 to 190°C was dried at a temperature The temperature was set to 100°C to produce a secondary battery pouch film. (Comparative Example 2) A two-component solvent-based emulsion with an initial temperature of 175 to 190°C was dried at a temperature The temperature was set to 120°C to produce a secondary battery pouch film. (Comparative Example 3) A two-component solvent-based emulsion with an initial temperature of 175 to 190°C was dried at a temperature The temperature was set to 135°C to produce a secondary battery pouch film. (Comparative Example 4) A two-component solvent-based emulsion with an initial temperature of 175 to 190°C was dried at a temperature The temperature was set to 150°C to produce a secondary battery pouch film. (Comparative Example 5) A two-component solvent-based emulsion with an initial temperature of 175 to 190°C was dried at a temperature The temperature was set to 165°C to produce a secondary battery pouch film. (Comparative Example 6) A two-component solvent-based emulsion with an initial temperature of 175 to 190°C was dried at a temperature The temperature was set to 180°C to produce a secondary battery pouch film. (Comparative Example 7) A two-component solvent-based emulsion with an initial temperature of 175 to 190°C was dried at a temperature The temperature was set to 200°C to produce a secondary battery pouch film. (Example 1) A two-component solvent-based emulsion with the starting temperature lowered to 135 to 150°C was used at a process temperature of The temperature was set to 100°C and a secondary battery pouch film was produced. (Example 2) A two-component solvent-based emulsion with a starting temperature lowered to 135 to 150°C was used at a process temperature of The temperature was set to 120°C to produce a secondary battery pouch film. (Example 3) A two-component solvent-based emulsion with a starting temperature lowered to 135 to 150°C was used at a process temperature of The temperature was set to 135°C to produce a secondary battery pouch film. (Example 4) A two-component solvent-based emulsion with a starting temperature lowered to 135 to 150°C was used at a process temperature of The temperature was set to 150°C to produce a secondary battery pouch film. (Comparative Example 8) A two-component solvent-based emulsion with the starting temperature lowered to 135 to 150°C was used at a process temperature of The temperature was set to 165°C to produce a secondary battery pouch film. (Comparative Example 9) A two-component solvent-based emulsion with the starting temperature lowered to 135 to 150°C was used at a process temperature of The temperature was set to 180°C to produce a secondary battery pouch film. (Comparative Example 10) A two-component solvent-based emulsion with the starting temperature lowered to 135 to 150°C was used at a process temperature of The temperature was set to 200°C to produce a secondary battery pouch film.

[0078] [Table 1]

[0079] Characterization <Evaluation of initial peel strength> (1) A secondary battery pouch film was cut into a piece 1.5 cm wide and 15 cm long to prepare a test piece. (2) The metal layer and the sealant layer were peeled off to measure the peel strength.

[0080] <Hydrofluoric acid resistance evaluation> (1) Cut the secondary battery pouch film to a length of 10 cm by 20 cm and heat seal both sides. did. (2) The manufacturing solution (electrolyte + water (concentration of water in the solution)) is placed inside the secondary battery pouch with two sides glued together. The pack was manufactured by adding 10,000 ppm (approximately 1%) of ethanol and heat-sealing it. (3) Stored at high temperature (85°C) for 24 hours. (4) Discard the electrolyte inside the pack and prepare a sample in the same manner as in the initial peel strength evaluation described above. (1.5cm wide, 15cm tall). (5) The peel strength between the metal layer and the sealant layer was measured.

[0081] <Electrolyte resistance evaluation> (1) A secondary battery pouch film was cut into a piece 1.5 cm wide and 15 cm long to prepare a test piece. (2) The prepared specimen was placed in a standard electrolyte (1.0M LiPF6 (EC / DEC / EMC: 1 / 1 / 1) and stored at high temperature (85°C) for 24 hours. (3) After the electrolyte was washed away, the metal layer and the sealant layer were peeled off to measure the peel strength.

[0082] <Formability evaluation> (1) Cut each of the produced secondary battery pouch films into pieces measuring 15cm x 15cm. The samples were prepared as follows. (2) Each sample was placed in a test mold (3cm x 4cm) manufactured by Kurimura Chemical Co., Ltd. Molded. (3) Repeat the forming evaluation while changing the forming depth setting, and if more than 10 samples are broken, We have now progressed. (4) The depth of the molding that did not break was measured at least 10 times.

[0083] <Puncture strength evaluation> (1) Prepare a sample of secondary battery pouch film with a width of 35 mm and a length of 600 mm. (2) Measure the puncture strength at intervals of approximately 40 mm from the outer layer to the inner layer. (3) After measuring the intensity 10 times, enter the average value.

[0084] For reference, in the case of formability, the higher the formability, the easier it is to manufacture the battery. The electrolyte resistance strength is 90% or more of the initial peel strength. The strength against hydrofluoric acid must be 5N / 15mm or more. The initial peel strength is 14N / 1 A thickness of 5mm or more is appropriate.

[0085] Table 2 below shows the physical property evaluation according to the curing start temperature and drying process temperature.

[0086] [Table 2]

[0087] As can be seen from the above, the starting temperature is high at 175 to 190°C (Comparative Examples 1, 2, 3, and 4). When emulsion is applied, the initial peel strength is 150℃ or less when the drying temperature is 150℃ or less. The initial peel strength is very low at 10N or less. Because the initial peel strength is low, the electrolyte resistance and fluorine resistance are low. When evaluating the acid strength, the sealant layer and the metal layer were completely separated. Ta.

[0088] When the drying temperature was 165 to 200°C (Comparative Examples 5, 6, and 7), the initial peel strength and electrolytic resistance It has excellent liquid strength and hydrofluoric acid resistance, and its puncture strength has increased to over 24N. The results showed that the formability was less than 6.5 mm.

[0089] When an emulsion with a lowered starting temperature of 135-150°C is used, the drying process temperature is 1 Only when the temperature was 00°C (Example 1), the initial peel strength was 10N / 15mm or less, and Under the drying process conditions of 0°C or higher (Examples and Comparative Examples 8 to 10), the initial peel strength was 12N / 15mm or higher. By lowering the starting temperature, adhesion was improved even at low drying process temperatures. I confirmed that.

[0090] However, under the condition of 120°C (Example 2), the hydrofluoric acid resistance strength did not reach 5N / 15mm. Under conditions of 35°C or higher (Examples 3 to 4, Comparative Examples 8 to 10), the initial peel strength, electrolyte resistance strength, The strength against hydrofluoric acid was also excellent.

[0091] As in Comparative Examples 1 to 7, the puncture strength was improved under the conditions of 165 to 200°C (Comparative Examples 8 to 10). The thickness increased, and the formability did not reach 6.5 mm.

[0092] Under the conditions of 135 to 150°C (Examples 3 and 4), the puncture strength increased to 20N or more, The moldability showed the best result of over 6.5 mm.

[0093] Therefore, only under the condition of the drying process temperature corresponding to the starting temperature, the initial peel strength and electrolyte resistance can be achieved. The strength and hydrofluoric acid resistance of the material were both adequate. As can be seen, when the drying temperature is 165°C or higher, the puncture resistance of the secondary battery pouch film is low. The strength increases significantly, and as a result, the formability deteriorates.

[0094] Therefore, in order to realize all the physical properties appropriately, the drying process temperature should be kept below 150℃. It is preferable to lower the starting temperature of the solvent-based emulsion to 150°C or less. It is preferable that:

[0095] Although non-limiting and exemplary embodiments of the present invention have been described above, the technical concept of the present invention can be applied to the following The present invention is not limited to the accompanying drawings or the above description. It is obvious to a person skilled in the art that the shape can be changed. Such modifications fall within the scope of the present invention.

Claims

1. a primer layer sandwiched between a metal layer and a melt-extruded resin layer or a sealant layer; The moldability is 6.5 mm or more, A secondary battery pouch film having an initial peel strength of 14.0 N / 15 mm or more.

2. Hydrofluoric acid resistance strength is 5.0 N / 15 mm or more, 2. The secondary battery pouch film according to claim 1, wherein the electrolyte resistance strength is 90% or more of the initial peel strength.

3. The secondary battery pouch film according to claim 2, wherein the electrolyte resistance strength is 14.0 N / 15 mm or more.

4. The moldability is 6.5 to 6.8 mm, The initial peel strength is 14.0 to 15.0 N / 15 mm, The electrolyte resistance strength is 14.0 to 14.5 N / 15 mm; The secondary battery pouch film according to claim 2, wherein the hydrofluoric acid resistance strength is 6.0 to 6.4 N / 15 mm.

5. The secondary battery pouch film according to claim 2, having a puncture strength of 21.0 to 23.0 N.

6. The secondary battery pouch film according to claim 1 , comprising a substrate layer, a metal layer, a primer layer, and a sealant layer, or a melt-extruded resin layer and a sealant layer, in that order.

7. 7. The secondary battery pouch film according to claim 6, comprising: a substrate layer; a metal layer; a corrosion prevention layer formed on at least one side of the metal layer; a primer layer formed on the inside of the metal layer; a polypropylene extrusion layer that is a melt-extruded resin layer; and a non-oriented polypropylene (CPP) layer that is a sealant layer.

8. the substrate layer is made of at least one of a polyester film and a polyimide film, The secondary battery pouch film according to claim 7 , wherein the metal layer is made of aluminum.

9. 7. The secondary battery pouch film according to claim 6, comprising, in this order, a substrate layer comprising a polyester film and a nylon film, a corrosion prevention layer, a metal layer, a corrosion prevention layer, a primer layer, a melt-extruded resin layer, and a sealant layer.

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