Metal composite film and its electrochemical device

Abstract

The present disclosure relates to the technical field of manufacturing aluminum-plastic films. It discloses a metal composite membrane comprising an outer substrate resin layer, an intermediate metal layer, and a heat-sealed resin layer. A corrosion-resistant layer is formed on the side of the intermediate metal layer that contacts the heat-sealed resin layer. The corrosion-resistant layer is formed by applying or heat-treating an anticorrosion solution. The anticorrosion solution contains a trivalent chromium compound, an inorganic acid, and an organic resin, and the mass ratio of the trivalent chromium compound, inorganic acid, and organic resin is (19-60):(3-60):(6-60). The anticorrosion solution may further contain titanate, and the mass ratio of the trivalent chromium compound, inorganic acid, organic resin, and titanate is (19-60):(3-60):(6-60):(1-10). Use of the anticorrosion solution formulation method within the above-specified range according to the present disclosure significantly improves the initial peel strength of the intermediate metal layer of the metal composite membrane from the heat-sealed resin layer and the corrosion resistance in aqueous and aqueous electrolyte environments.

Description

Technical Field

[0001] <Cross - reference to Related Applications> This application claims the priority of Chinese Patent Applications with application numbers CN202011430235.6, titled "Metal Composite Film, Electrochemical Device", filed with the China National Intellectual Property Administration on December 7, 2020, and CN202110426578.3, titled "Metal Composite Film and Its Electrochemical Device", filed with the China National Intellectual Property Administration on December 7, 2020, and all of its content is incorporated herein by reference.

[0002] The present disclosure relates to the technical field of manufacturing aluminum plastic films, and in particular, to metal composite films and electrochemical devices using such metal composite films.

Background Art

[0003] Currently, lithium - ion batteries are mainly divided into three types: square, cylindrical, and pouch - type. Among them, for square and cylindrical batteries, their housings mainly adopt shells such as aluminum alloys and stainless steels. The housing made of aluminum alloy may be aluminum, but the pouch housing formed by laminating metal and resin adopts a metal composite film, thereby greatly improving the problem of lack of flexibility in the external shape design of rigid - packaged batteries.

[0004] However, as an exterior material for batteries, metal composite films are required to have the performance of withstanding corrosion by electrolytes, thereby preventing problems such as liquid leakage occurring in the battery housing and ensuring the service life of the battery.

[0005] Generally, the metals in the metal composite film for the outer packaging of lithium-ion batteries must all be subjected to anti-corrosion treatment. If the effect of the anti-corrosion treatment is insufficient, when moisture is mixed in during the battery manufacturing process, it will react with the lithium salt in the electrolyte to generate corrosive hydrogen fluoride (HF). Hydrogen fluoride will reach the surface of the intermediate metal layer through the inner heat-sealing resin layer and the inner layer adhesive layer, corrode the metal, and cause detachment between the metal and the inner heat-sealing resin layer, which will likely lead to leakage of the electrolyte from the battery. Therefore, the anti-corrosion treatment of the metal has a very significant impact on the metal composite film.

[0006] Currently, after the metal is treated with several anti-corrosion liquids, it can improve the corrosion resistance of the metal composite film in some general electrolyte environments. However, during the long-term use of the battery, there is a risk that moisture will pass through the battery outer packaging to generate hydrogen fluoride (HF) in the electrolyte, which will make the effect of the anti-corrosion treatment of this anti-corrosion liquid insufficient, and the interlayer separation of the metal composite film for lithium-ion batteries is likely to occur, affecting the popularization and use of the metal composite film in the field of lithium-ion batteries.

Summary of the Invention

[0007] The present disclosure provides a metal composite film including an outer base resin layer, an intermediate metal layer, and a heat-sealing resin layer. An anti-corrosion layer is formed on the side of the intermediate metal layer that contacts the heat-sealing resin layer. The anti-corrosion layer is formed by applying or heat-treating an anti-corrosion liquid. The mass percentages of the trivalent chromium compound, inorganic acid, and organic resin in the anti-corrosion liquid are 1.9 - 6%, 0.3 - 6%, and 0.6 - 6% respectively. The trivalent chromium compound consists of at least one of chromium nitrate, chromium phosphate, and chromium chloride.

[0008] In some embodiments, the anti-corrosion liquid further contains fluoride. The mass percentages of the trivalent chromium compound, inorganic acid, fluoride, and organic resin in the anti-corrosion liquid are 1.9 - 6%, 0.3 - 6%, 0 - 10%, and 0.6 - 6% respectively.

[0009] In some embodiments, the components of the anticorrosion layer further include that an inner layer adhesive layer is provided between the anticorrosion layer and the heat-sealing resin layer.

[0010] In some embodiments, the components of the anticorrosion layer further include that an outer layer adhesive layer is provided between the outer base material resin layer and the intermediate metal layer.

[0011] In some embodiments, the metal composite film further includes a coloring layer, and the coloring layer is provided between the outer base material resin layer and the outer layer adhesive layer, or the coloring layer is formed by adding a pigment to the outer layer adhesive layer.

[0012] In some embodiments, the metal composite film further includes that a coloring layer is provided outside the outer base material resin layer.

[0013] In some embodiments, an outer anticorrosion layer is provided on the side of the intermediate metal layer that contacts the outer layer adhesive layer or the outer base material resin layer.

[0014] In some embodiments, the inorganic acid consists of one or more of nitric acid and phosphoric acid.

[0015] In some embodiments, the organic resin is a polyacrylic acid-based resin or consists of a polyacrylic acid-based resin and polyvinyl alcohol.

[0016] In some embodiments, the polyacrylic acid-based resin is one or more of polyacrylic acid, polymethyl acrylate, a copolymer of acrylic acid and maleic acid, a copolymer of acrylic acid and styrene and its sodium salt and ammonium salt derivatives, and the weight average molecular weight of the polyacrylic acid-based resin is 10,000 to 800,000.

[0017] In some embodiments, the thickness of the anticorrosion layer is 1 nm to 3.0 μm.

[0018] In some embodiments, the thickness of the anticorrosion layer is 1 nm to 1.5 μm.

[0019] In some embodiments, the chromium content in the anticorrosion layer is between 8 and 50 mg / m 2 .

[0020] In some embodiments, the chromium content in the anticorrosion layer is between 10 and 30 mg / m 2 .

[0021] In some embodiments, the anticorrosion layer is formed by applying and heat-treating an anticorrosion liquid.

[0022] In some embodiments, the coating methods include bar coating method, roll coating method, gravure coating method and dipping method.

[0023] In some embodiments, the fluoride is one or more selected from chromium fluoride and aluminum fluoride.

[0024] In some embodiments, a solution-type adhesive is used for the inner layer adhesive layer. The components of the solution-type adhesive include acid-modified polyolefin resin and a curing agent. The thickness of the inner layer adhesive layer is 1 to 10 μm.

[0025] In some embodiments, the melting point of the acid-modified polyolefin resin is between 60 and 155 °C, the weight average molecular weight is in the range of 10,000 to 150,000, and the acid value is in the range of 0.5 to 200 mg KOH / g.

[0026] In some embodiments, the curing agent is one or more selected from isocyanate, epoxy resin or oxazoline, or one or more selected from triethylamine and N,N-dimethylethanolamine. The acid modifier used for the acid-modified polyolefin resin is one of maleic anhydride, methacrylic acid, acrylic acid and itaconic anhydride.

[0027] In some embodiments, when one or more of the above curing agents are selected from triethylamine and N,N-dimethylethanolamine, the mass ratio of the acid-modified polyolefin resin to the above curing agent is 10:1 to 125:1.

[0028] In some embodiments, the mass ratio of the acid-modified polyolefin resin to the above curing agent is 15:1 to 50:1.

[0029] In some embodiments, the acid-modified polyolefin resin is a single layer or multiple layers composed of a mixture of one or more of a polypropylene block copolymer resin, a polypropylene random copolymer resin, and a homopolypropylene resin in which the content of polypropylene having a melting point of 110 °C or higher exceeds 50%.

[0030] In some embodiments, a hot-melt inner layer adhesive is used for the above inner layer adhesive layer, the component of the hot-melt inner layer adhesive contains an acid-modified polyolefin resin, and the thickness of the inner layer adhesive layer is 2 to 80 μm.

[0031] In some embodiments, the melting point of the acid-modified polyolefin resin is between 135 °C and 165 °C, and the MFR (230 °C) is between 3 g / 10 min and 15 g / 10 min.

[0032] In some embodiments, the acid-modifying agent used for the acid-modified polyolefin resin is one of maleic anhydride, methacrylic acid, acrylic acid, and itaconic anhydride, and the degree of modification of the polyolefin resin is 1% to 15%.

[0033] In some embodiments, the heat-sealing resin layer is a single layer or a composite layer composed of a mixed resin of one or two or more of an acid-modified polyolefin resin, a homopolypropylene resin, a polypropylene block copolymer resin, a polypropylene random copolymer resin, and a polyethylene resin.

[0034] In some embodiments, the melting point of the constituent resin of the heat-sealing resin layer is between 120 and 162 °C, the MFR (230 °C) is 2 to 15 g / 10 min, and the thickness of the heat-sealing resin layer is 20 to 120 μm.

[0035] The present disclosure provides an electrochemical device using the metal composite film according to any one of the above.

Brief Description of the Drawings

[0036] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. It should be understood that the embodiments described herein are merely for explaining and interpreting the present disclosure and do not limit the present disclosure.

[0037]

Figure 1

Embodiments for Carrying Out the Invention

[0038] One embodiment of the present disclosure includes an outer base resin layer, an intermediate metal layer, and a heat-sealing resin layer. A corrosion protection layer is formed on the side of the intermediate metal layer that contacts the heat-sealing resin layer. The components of the corrosion protection layer include a trivalent chromium compound, an inorganic acid, and an organic resin. The mass ratio of the trivalent chromium compound, inorganic acid, and organic resin is (19 - 60):(3 - 60):(6 - 60). The trivalent chromium compound consists of at least one of chromium nitrate, chromium phosphate, and chromium chloride, providing a metal composite film.

[0039] In some embodiments, the corrosion protection layer is formed by applying or heat-treating a corrosion protection liquid, and the mass ratio of the trivalent chromium compound, inorganic acid, and organic resin in the corrosion protection liquid is (19 - 60):(3 - 60):(6 - 60).

[0040] In some embodiments, the mass ratio of the trivalent chromium compound, inorganic acid, and organic resin may be (19 - 40):(3 - 60):(6 - 60), (19 - 60):(3 - 50):(6 - 60), (19 - 60):(3 - 60):(6 - 50), (20 - 55):(5 - 60):(10 - 60), or (20 - 60):(5 - 60):(10 - 60). In some embodiments, the components of the anticorrosion layer further include a fluoride, and the mass ratio of the trivalent chromium compound, inorganic acid, organic resin, and fluoride is (19 - 60):(3 - 60):(6 - 60):(1 - 10).

[0041] In some embodiments, the anticorrosion liquid further includes a fluoride, and the mass ratio of the trivalent chromium compound, inorganic acid, organic resin, and fluoride is (19 - 60):(3 - 60):(6 - 60):(0 - 10).

[0042] In some embodiments, the mass ratio of the trivalent chromium compound, inorganic acid, organic resin, and fluoride may be (19 - 50):(3 - 60):(6 - 60):(1 - 10), (19 - 60):(3 - 50):(6 - 60):(1 - 10), (19 - 60):(3 - 60):(6 - 50):(1 - 10), (19 - 60):(3 - 60):(6 - 60):(1 - 5), (20 - 60):(5 - 60):(10 - 60):(1 - 10), or (20 - 60):(10 - 60):(10 - 50):(5 - 10).

[0043] In some embodiments, the metal composite film includes an outer base resin layer, an intermediate metal layer, and a heat-sealing resin layer. An anticorrosion layer is formed on the side of the intermediate metal layer that contacts the heat-sealing resin layer. The anticorrosion layer is formed by applying or heat-treating an anticorrosion liquid. The mass percentages of the trivalent chromium compound, inorganic acid, and organic resin in the anticorrosion liquid are 1.9 - 6%, 0.3 - 6%, and 0.6 - 6% respectively. The trivalent chromium compound is composed of at least one of chromium nitrate, chromium phosphate, and chromium chloride.

[0044] In some embodiments, the anticorrosive liquid further contains fluoride, and the mass percentage of the trivalent chromium compound, inorganic acid, fluoride, and organic resin in the anticorrosive liquid is 1.9 - 6%, 0.3 - 6%, 0 - 10%, and 0.6 - 6% respectively.

[0045] Any of the above metal composite films with or without a fluoride component anticorrosive layer may further include an inner adhesive layer provided between the anticorrosive layer and the heat-sealing resin layer.

[0046] In some typical embodiments, it further includes an outer adhesive layer provided between the outer base material resin layer and the intermediate metal layer.

[0047] Any of the above metal composite films with or without a fluoride component anticorrosive layer may further include an outer adhesive layer provided between the outer base material resin layer and the intermediate metal layer.

[0048] Any of the above metal composite films with various structures may include a coloring layer. The coloring layer may be provided between the outer base material resin layer and the outer adhesive layer, or the coloring layer may be formed by adding a pigment to the outer adhesive layer.

[0049] Also, the coloring layer may be provided outside the outer base material resin layer.

[0050] The metal composite film may be subjected to a matte finish treatment, that is, a layer of matte agent is applied on the surface of the outer base material resin layer.

[0051] Any of the above metal composite films may have an outer anticorrosive layer provided on the side in contact with the outer adhesive layer of the intermediate metal layer or the outer base material resin layer.

[0052] Regardless of theory, it is considered that the trivalent chromium compound can form a coordination cross-linked structure centered on Cr atoms on the metal surface and play a role in increasing the cross-linking degree of the metal surface anticorrosive film.

[0053] In any one of the above metal composite films, the inorganic acid consists of one or more of nitric acid and phosphoric acid. Apart from theory, the inorganic acid is considered to play a role in removing the oxide film on the metal surface.

[0054] In any one of the above metal composite films, the organic resin is a polyacrylic acid-based resin, or consists of a polyacrylic acid-based resin and polyvinyl alcohol. The polyacrylic acid-based resin is one or more of polyacrylic acid, polymethyl acrylate, copolymers such as acrylic acid and maleic acid, copolymers of acrylic acid and styrene and their derivatives such as sodium salts and ammonium salts. Optionally, it is a derivative of polyacrylic acid such as ammonium salt, sodium salt or amine salt of polyacrylic acid. Also, the polyacrylic acid-based resin is optionally a copolymer of acrylic acid and dicarboxylic acid or dicarboxylic anhydride, and more optionally, an ammonium salt, sodium salt or amine salt of the copolymer of acrylic acid and dicarboxylic acid or dicarboxylic anhydride. The polyacrylic acid-based resin plays a role in improving the film-forming property of the metal surface anticorrosion layer.

[0055] The weight average molecular weight of the polyacrylic acid-based resin is, for example, about 1,000 to 1,000,000, and for example, 5,000 to 1,000,000, 10,000 to 1,000,000, 50,000 to 900,000, 100,000 to 900,000, 200,000 to 800,000 or 500,000 to 800,000, and for example, it may be 1,000, 5,000, 10,000, 50,000, 100,000, 200,000, 300,000, 400,000, 500,000, 600,000, 700,000, 800,000, 900,000 or 1,000,000. In some typical embodiments, the weight average molecular weight of the polyacrylic acid-based resin is about 3,000 to 800,000, for example, about 10,000 to 800,000.

[0056] Apart from theory, the higher the weight-average molecular weight of the polyacrylic acid resin, the higher its durability. However, the water solubility of the polyacrylic acid resin is reduced, the coating solution becomes unstable, and it is considered to affect the manufacturing stability. Conversely, the lower the weight-average molecular weight of the polyacrylic acid resin, the lower its durability. When the weight-average molecular weight of the polyacrylic acid resin is 1000 or more, its durability is high, and when the weight-average molecular weight is 1 million or less, the coating stability is good during manufacturing.

[0057] The proportion range of the components in the anticorrosion layer of the present disclosure was found through a large amount of research by the inventors. The proportion range plays a decisive role in solving the technical problems of the present disclosure and achieving the technical effects, and its influence is explained as follows: When the proportion of the trivalent chromium compound is within the above range, the folding resistance and toughness of the metal composite film are improved. During bending or forming processes, cracking of the anticorrosion layer is prevented, intrusion of the electrolytic solution is prevented, the insulation property is enhanced, and leakage of the electrolytic solution caused by peeling between the intermediate metal layer and the inner heat-sealing resin layer due to corrosion by hydrogen fluoride is prevented. Moreover, it has good crosslinkability, a good anticorrosion effect, and a good anticorrosion action is achieved. When the proportion of the trivalent chromium compound exceeds the above range, the metal surface anticorrosion film becomes hard, and accordingly, the folding resistance of the metal composite film deteriorates. When bending or forming processes are performed, cracks occur in the anticorrosion layer, the insulation property becomes low due to intrusion of the electrolytic solution, peeling between the intermediate metal layer and the inner heat-sealing resin layer is caused by corrosion by hydrogen fluoride, and leakage of the electrolytic solution occurs. When the proportion of the trivalent chromium compound is lower than the above range, the crosslinking degree of the metal surface anticorrosion film is low, and the anticorrosion action is not achieved. When the proportion of the inorganic acid is within the above range, a highly corrosion-resistant corrosion protection layer is provided, the resistance to corrosion by hydrogen fluoride is improved, the oxide film on the metal surface is completely removed, good bonding properties are imparted to the corrosion protection layer and the intermediate metal layer, and during the long-term storage period of the device, the peeling between the intermediate metal layer and the inner heat-sealing resin layer can be effectively prevented. When the proportion of the inorganic acid exceeds the above range, the proportion of the trivalent chromium compound and the organic resin in the corrosion protection layer becomes low, and a highly corrosion-resistant corrosion protection layer cannot be obtained. Therefore, the resistance to corrosion by hydrogen fluoride deteriorates. When the proportion of the inorganic acid is lower than the above range, the oxide film on the metal surface is not completely removed, the bonding property between the corrosion protection layer and the intermediate metal layer deteriorates, and during the long-term storage period, the intermediate metal layer and the inner heat-sealing resin layer may be peeled off. When the proportion of the organic resin is within the above range, a corrosion protection layer with an appropriate thickness is formed. The metal surface corrosion protection film is difficult to delaminate and break, the effective corrosion resistance of the metal composite film is ensured, it is difficult to absorb water, HF is difficult to generate in the electrolyte environment, and its corrosion resistance is improved. When the proportion of the organic resin is lower than the above range, the metal surface corrosion protection film delaminates and is easily broken, and accordingly, the corrosion resistance of the metal composite film deteriorates. When the proportion of the organic resin exceeds the above range, the metal surface corrosion protection film becomes too thick, is easily broken, absorbs water easily, HF is easily generated in the electrolyte environment, and the metal surface is corroded. Accordingly, the corrosion resistance of the metal composite film deteriorates. When the proportion of the fluoride is within the above range, the crosslinkability of trivalent chromium is improved, the formation of the corrosion protection layer is effectively promoted, the risk of peeling between the intermediate metal layer and the inner heat-sealing resin layer is avoided, waste of resources is avoided, the effect of resisting corrosion by hydrofluoric acid (HF) is improved, and the corrosion protection effect of protecting the metal surface is well achieved. When the proportion of the fluoride exceeds the above range, the crosslinkability of trivalent chromium deteriorates, which affects the formation of the corrosion protection layer, there is a risk of peeling between the intermediate metal layer and the inner heat-sealing resin layer, and waste of resources is also caused. When the proportion of the fluoride is lower than the above range, the effect of resisting corrosion by hydrofluoric acid (HF) is poor, and the corrosion protection effect of protecting the metal surface is not achieved.

[0058] In any one of the above-described metal composite films, the thickness of the anticorrosion layer is 1 nm to 3.0 μm. For example, the thickness of the anticorrosion layer may be 100 nm to 3.0 μm, 500 nm to 3.0 μm, 1.0 μm to 3.0 μm, or 1 nm to 2.0 μm. For example, it may be 1 nm, 50 nm, 100 nm, 200 nm, 400 nm, 800 nm, 1.0 μm, 1.5 μm, 2.0 μm, 2.5 μm, or 3.0 μm. For example, the thickness of the anticorrosion layer is 1 nm to 1.5 μm.

[0059] In any one of the above-described metal composite films, the chromium content in the anticorrosion layer is between 8 and 50 mg / m 2 . For example, the chromium content may be 8 to 45 mg / m 2 , 8 to 40 mg / m 2 or 10 to 35 mg / m 2 . For example, it may be 8 mg / m 2 , 10 mg / m 2 , 12 mg / m 2 , 14 mg / m 2 , 18 mg / m 2 , 20 mg / m 2 , 22 mg / m 2 , 24 mg / m 2 , 26 mg / m 2 , 28 mg / m 2 , 30 mg / m 2 , 35 mg / m 2 , 38 mg / m 2 , 40 mg / m 2 , 43 mg / m 2 , 46 mg / m 2 , 50 mg / m 2 . For example, the chromium content in the anticorrosion layer is between 10 and 30 mg / m 2 .

[0060] In any one of the above-described metal composite films, the anticorrosion layer is formed by applying and heat-treating an anticorrosion liquid.

[0061] In some embodiments, the coating methods include a bar coating method, a roll coating method, a gravure coating method, and a dipping method.

[0062] When the anti-corrosion layer contains a component such as fluoride, the fluoride is one or more selected from chromium fluoride and aluminum fluoride. Here, the fluoride plays a role in increasing the resistance of the metal film to hydrofluoric acid (HF).

[0063] For the inner layer adhesive layer of the metal composite film according to the present disclosure, a solution-type adhesive can be used. The components of the solution-type adhesive include an acid-modified polyolefin resin and a curing agent. The thickness of the inner layer adhesive layer is 1 to 10 μm, for example, 5 to 10 μm, 1 to 5 μm or 2 to 8 μm, for example, 1 to 5 μm.

[0064] In some embodiments, the melting point of the acid-modified polyolefin resin is between 60 and 155 °C, the weight average molecular weight is in the range of 10,000 to 150,000, for example, 20,000 to 150,000, 30,000 to 150,000, 50,000 to 150,000 or 10,000 to 100,000, and the acid value is in the range of 0.5 to 200 mg KOH / g, for example, 1 to 200 mg KOH / g, 10 to 200 mg KOH / g, 50 to 200 mg KOH / g or 100 to 200 mg KOH / g.

[0065] In some typical embodiments, the solution-type inner layer adhesive using an organic solvent has a weight average molecular weight of the acid-modified polypropylene of 10,000 to 150,000, for example, 20,000 to 150,000, 50,000 to 150,000, 80,000 to 150,000 or 10,000 to 100,000, and a melting point of 60 to 130 °C.

[0066] In some typical embodiments, in the case of a solution-type inner layer adhesive using water or alcohol as a solvent, the weight-average molecular weight characteristic of the acid-modified polypropylene is 5,000 to 800,000, for example, 10,000 to 150,000, and the melting point is 100 to 155 °C. In some embodiments, the weight-average molecular weight of the acid-modified polypropylene is, for example, 5,000 to 700,000, 10,000 to 800,000, 20,000 to 700,000 or 20,000 to 500,000, for example, 10,000, 50,000, 100,000, 150,000, 200,000, 250,000, 300,000, 350,000, 400,000, 450,000, 500,000, 550,000, 600,000, 650,000, 700,000, 750,000.

[0067] In some embodiments, the curing agent is one or more selected from isocyanate, epoxy resin or oxazoline, or one or more selected from triethylamine, N,N-dimethylethanolamine, and the acid modifier used for the acid-modified polyolefin resin is one of maleic anhydride, methacrylic acid, acrylic acid, itaconic anhydride.

[0068] In some typical embodiments, when the curing agent is one or more selected from triethylamine, N,N-dimethylethanolamine, the mass ratio of the acid-modified polyolefin resin to the curing agent is 10:1 to 125:1. For example, the mass ratio of the acid-modified polyolefin resin to the curing agent is 15:1 to 50:1. For example, the mass ratio of the acid-modified polyolefin resin to the curing agent is 15:1 to 40:1, 20:1 to 50:1 or 20:1 to 50:1.

[0069] In some typical embodiments, the acid-modified polyolefin resin is a single layer or multiple layers composed of a mixture of one or more of a polypropylene block copolymer resin (B-PP), a polypropylene random copolymer resin (R-PP), and a homopolypropylene resin (H-PP) with a content of polypropylene having a melting point of 110 °C or higher exceeding 50%.

[0070] For the inner layer adhesive layer of the metal composite film according to the present disclosure, a hot-melt type inner layer adhesive can be used. The components of the hot-melt type inner layer adhesive include an acid-modified polyolefin resin. The thickness of the inner layer adhesive layer is 2 to 80 μm, for example, 5 to 80 μm, 10 to 80 μm, 20 to 80 μm, or 30 to 80 μm, for example, 5 to 50 μm.

[0071] In some embodiments, the melting point of the acid-modified polyolefin resin is between 135 and 165 °C, and the MFR (230 °C) is between 3 and 15 g / 10 min.

[0072] In some embodiments, the acid modifier used for the acid-modified polyolefin resin is one of maleic anhydride, methacrylic acid, acrylic acid, and itaconic anhydride. The degree of modification of the polyolefin resin is 1 to 15%, for example, 3 to 12%.

[0073] In any one of the above metal composite films, the heat-sealing resin layer is a single layer or a composite layer composed of one or more mixed resins selected from acid-modified polyolefin resin, homopolypropylene resin, polypropylene block copolymer resin, polypropylene random copolymer resin, and polyethylene resin.

[0074] In some embodiments, the melting point of the constituent resin of the heat-sealing resin layer is between 120 and 162 °C, and the MFR (230 °C) is 2 to 15 g / 10 min, for example, between 130 and 162 °C, and the MFR (230 °C) is 3 to 12 g / 10 min. The thickness of the heat-sealing resin layer is 20 to 120 μm, for example, 20 to 110 μm, 20 to 100 μm, or 20 to 80 μm, for example, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 90 μm, 100 μm, 120 μm, for example, 25 to 80 μm.

[0075] When the heat-sealing resin layer is a composite layer, the thickness of the resin layer on the side opposite to the heat-sealing resin layer that composes with the intermediate metal layer should be 2 μm or more, and the melting point is 130 to 152 °C.

[0076] By hot extrusion, one or more heat-sealing resin layers are formed and compounded with an intermediate metal layer having an inner adhesive layer formed in advance. The inner adhesive layer must be heat-treated at a temperature not exceeding 60°C above its melting point.

[0077] Compound with the intermediate metal layer by hot extrusion to form one or more heat-sealing resin layers. The inner resin layer in contact with the intermediate metal layer in the inner heat-sealing resin layer must be heat-treated at a temperature not exceeding 60°C above its melting point.

[0078] In any one of the above metal composite films, the outer base resin layer may be a single-layer or multi-layer composite film formed of one or more materials selected from polymer materials such as inflation nylon, simultaneously or non-simultaneously biaxially stretched nylon, simultaneously or non-simultaneously biaxially stretched polyethylene terephthalate (PET), simultaneously or non-simultaneously biaxially stretched polybutylene terephthalate (PBT), polyimide (PI), and thermosetting polyamide. The outer base resin layer may also be a single-layer or multi-layer composite film formed of one or more materials selected from extrusion, coating, lamination, and thermal bonding. The total thickness of the outer base resin layer is 5 - 35 μm, for example, 10 - 35 μm, 15 - 35 μm, or 5 - 30 μm, for example, 5 μm, 8 μm, 10 μm, 12 μm, 15 μm, 20 μm, 23 μm, 25 μm, 30 μm, 32 μm, 35 μm.

[0079] In any one of the above metal composite films, the outer adhesive layer is one or two types of two-component or multi-component polyester polyol and polyurethane-modified polyester polyol and isocyanate, and the thickness of the outer adhesive layer is 2 - 5 μm, for example, 2 μm, 3 μm, 4 μm, 5 μm.

[0080] In any one of the above metal composite films, the intermediate metal layer is composed of one or more single layers or multiple layers selected from aluminum foil, iron plate, stainless steel foil, or nickel-plated iron plate, and the thickness of the intermediate metal layer is 20 to 100 μm, for example, 30 to 100 μm, 40 to 100 μm, 50 to 100 μm, 20 to 90 μm, 20 to 80 μm, for example, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm.

[0081] One embodiment of the present disclosure provides an electrochemical device using any one of the above metal composite films.

[0082] The metal composite film and the electrochemical device provided by the present disclosure overcome the defects of the prior art and are long-term stable corrosion-resistant metal composite film and electrochemical device. Among them, 1) When the inventors explored, verified, adjusted, and confirmed the ratios of trivalent chromium compounds, inorganic acids, and organic resins, which are the main components of the intermediate metal surface corrosion protection layer, through a large number of experiments, when the contents of trivalent chromium compounds, inorganic acids, and organic resins on the intermediate metal surface are within the claim scope of the present disclosure, the initial peeling strength between the intermediate metal layer and the thermally welded resin layer of the metal composite film and the corrosion resistance in the electrolyte environment with and without water can be significantly improved. 2) Based on the above 1), by adding a specific ratio range of fluoride components explored, verified, and confirmed by the inventors through a large number of experiments to the intermediate metal surface corrosion protection layer, the initial peeling strength between the intermediate metal layer and the thermally welded resin layer of the metal composite film and the corrosion resistance in the electrolyte environment with and without water can be further improved.

[0083] Hereinafter, specific embodiments of the present disclosure will be described in detail with reference to the drawings. It should be understood that the specific embodiments described herein are only for explaining and interpreting the present disclosure and do not limit the present disclosure.

[0084] As shown in FIG. 1, a specific embodiment of the present disclosure provides a metal composite film including, in order from the cell outward, a heat-sealing resin layer 8, an inner adhesive layer 7, a corrosion-resistant layer 6, an intermediate metal layer 5, an outer corrosion-resistant layer 4, a coloring layer 3, an outer adhesive layer 2, and an outer base resin layer 1. Hereinafter, the structure of the exterior material for a battery device in some embodiments of the present disclosure will be described in detail.

[0085] Outer base resin layer 1: In the present disclosure, the outer base resin layer 1 is installed so as to be able to function as a base material for a packaging material for a lithium-ion battery. The outer base resin layer 1 is located on the outer layer side of the packaging material for a lithium-ion battery.

[0086] Regarding the raw material for forming the outer base resin layer 1, there is no particular limitation as long as it has at least insulating properties as a function of the base material.

[0087] There are multiple methods for manufacturing the outer base resin layer 1. For example, a resin film product may be directly formed from a resin, or it may be a coated resin product. As the resin film, it may be an unstretched film or a stretched film. As the stretched film, it may be a uniaxially stretched film or a biaxially stretched film, and preferably, it is a biaxially stretched film. As the method for manufacturing the biaxially stretched film, for example, a sequential biaxial stretching method, an inflation method, or a simultaneous stretching method is used. As the resin coating method, for example, a roll coating method, a microgravure coating method, an extrusion coating method, etc. are used.

[0088] Examples of the resin for forming the outer base resin layer 1 include resins such as polyester, polyamide, polyolefin, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, and phenol resin, or modified products of these resins. Further, the resin for forming the outer base resin layer 1 may be a copolymer of these resins, a modified product of the copolymer, a mixture of these resins, and a single layer or multiple layers are preferred.

[0089] Among them, the resins for forming the outer base resin layer 1 are selectively the polyester and polyamide mentioned above.

[0090] As the polyester, in some embodiments, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene isophthalate, copolyester, etc. can be mentioned. Further, as the copolyester, a copolyester having polyethylene terephthalate as the main repeating unit, etc. can be mentioned. In some embodiments, a copolymer polyester formed by polymerizing ethylene isophthalate with polyethylene terephthalate as the main repeating unit (hereinafter abbreviated as copolyester (terephthalate / isophthalate)), copolyester (terephthalate / adipate), copolyester (terephthalate / sodium isophthalate), copolyester (terephthalate / phenyl-dicarboxylate), copolyester (terephthalate / decanedicarboxylate), etc. These polyesters may be used alone or in combination of two or more.

[0091] Also, as the polyamide, in some embodiments, aliphatic polyamides such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, and a copolymer of nylon 6 and nylon 66, nylon 6I, nylon 6T, nylon 6IT, nylon 6I6T (I represents isophthalic acid, t represents terephthalic acid) containing structural units derived from terephthalic acid and / or isophthalic acid, such as hexamethylenediamine-isophthalic acid-terephthalic acid copolymer polyamide, polyamide MXD6 (polyamide PACM6 (poly-bis(4-aminocyclohexyl)methane adipamide), etc. of aromatic polyamides can be mentioned. These polyamides may be used alone or in combination of two or more.

[0092] The outer substrate resin layer 1 selectively contains at least one of a polyester film, a polyamide film, and a polyolefin film, selectively contains at least one of a stretched polyester film, a stretched polyamide film, and a stretched polyolefin film, selectively contains at least one of a stretched polyethylene terephthalate film, a stretched polybutylene terephthalate film, a stretched nylon film, and a stretched polypropylene film, and selectively contains at least one of a biaxially stretched polyethylene terephthalate film, a biaxially stretched polybutylene terephthalate film, a biaxially stretched nylon film, and a biaxially stretched polypropylene film.

[0093] The outer substrate resin layer 1 may be a single layer or may be composed of two or more layers. When the outer substrate resin layer 1 is composed of two or more layers, the outer substrate resin layer 1 may be a composite film formed by the action of a binder, or may be a resin composite film formed by co-extruding resins to form two or more layers. Further, the resin composite film formed by co-extruding resins to form two or more layers may be used as the outer substrate resin layer 1 in an unstretched state, or may be used as the outer substrate resin layer 1 after uniaxial stretching or biaxial stretching.

[0094] In the outer base resin layer 1, examples of the laminate of two or more resin films include a composite film of a polyester film and a nylon film, a nylon composite film of two or more layers, a polyester composite film of two or more layers, etc. Optionally, it is a laminate of a stretched nylon film and a stretched polyester film, a nylon composite film of two or more layers, or a polyester composite film of two or more layers. For example, when the outer base resin layer used is a two-layer resin composite film, optionally, it is a composite film of a polyester resin film and a polyester resin film, a composite film of a polyamide resin film and a polyamide resin film, or a composite film of a polyester resin film and a polyamide resin film. Optionally, it is a composite film of a polyethylene terephthalate film and a polyethylene terephthalate film, a composite film of a polybutylene terephthalate film and a polybutylene terephthalate film, a composite film of a nylon film and a nylon film, or a composite film of a polyethylene terephthalate film and a nylon film. Further, since the polyester resin is hardly discolored even when the electrolytic solution adheres to the surface, when the outer base resin layer 1 used is a resin composite film of two or more layers, optionally, the polyester resin film is located in the outermost layer of the outer base resin layer 1.

[0095] When the outer substrate resin layer 1 is a resin composite film of two or more layers, the two or more resin films may be laminated with a binder. As a selective binder, an adhesive solution having the same components as the outer layer adhesive can be used. Furthermore, the method for laminating two or more resin films is not particularly limited, and methods such as dry lamination method, sandwich lamination method, extrusion lamination method, and thermal lamination method can be used, and optionally, dry lamination is used. When laminating by the dry lamination method, as the reactive binder for the outer layer, a reactive polyurethane binder is selectively used. In this case, the thickness of the adhesive layer may be about 2 to 5 μm. When forming the outer substrate resin layer by the resin coating method, first, the resin is dissolved in an organic solvent, and the outer substrate resin layer can be formed by coating. The coating resin can be a phenolic resin such as polyamide resin, polyimide resin, polyurethane resin, epoxy resin, acrylic resin, polyester resin, polyamide resin, polyimide resin, fluorine-based copolymer resin, polyester resin, etc., an amino resin such as polyester resin, polycarbonate resin, urea resin, and melamine resin.

[0096] Furthermore, one or more of additives such as lubricants, flame retardants, antiblocking agents, antioxidants, light stabilizers, thickeners, and antistatic agents can be added to the surface and inside of the outer substrate resin layer 1.

[0097] From the perspective of improving the formability of the packaging material for lithium-ion batteries, selectively, a layer composed of a lubricant is formed on the surface of the outer base resin layer 1. The lubricant is not particularly limited, and is selectively an amide-based lubricant. The amide-based lubricant includes saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, hydroxymethyl amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid amides, and aromatic bisamides. Taking saturated fatty acid amides as an example, lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide, etc. can be used. Taking unsaturated fatty acid amides as an example, oleic acid amide, erucic acid amide, etc. can be mentioned. Substituted amides include N-oleopalmitic acid amide, N-stearyl amide, N-stearyl amide, N-oleostearyl amide, and N-stearyl amide. Also, hydroxymethyl amides include hydroxymethyl stearic acid amide, etc. Saturated fatty acid bisamides include methylene bisstearic acid amide, ethylidene bisoctylic acid amide, ethylidene bislauric acid amide, ethylidene bisstearic acid amide, ethylidene bishydroxystearic acid amide, ethylidene bisbehenic acid amide, and hexamethylene bisstearic acid hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, n,n , -distearyl adipic acid amide, n,n , -distearyl sebacic acid amide, etc. Unsaturated fatty acid bisamides include ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, n,n , -dioleyl adipic acid amide and n,n , -dioleyl sebacic acid amide. Fatty acid ester amides include stearyl amide ethyl stearate, etc. Also, aromatic bisamides include isophthal bisstearic acid amide, isophthal bishydroxystearic acid amide, n,n , -distearyl isophthalic acid amide, etc. The lubricant may be used alone or in combination of two or more.

[0098] When there is a lubricant on the surface of the outer substrate resin layer 1, the coating amount is not particularly limited. For example, it is about 3 mg / m 2 or more, for example, 3 mg / m 2 , 4 mg / m 2 , 5 mg / m 2 , 8 mg / m 2 , 10 mg / m 2 , 12 mg / m 2 , 14 mg / m 2 , 16 mg / m 2 , 18 mg / m 2 , 20 mg / m 2 , 22 mg / m 2 , 24 mg / m 2 , 26 mg / m 2 , 28 mg / m 2 , 30 mg / m 2 and applied, for example, in the range of 4 - 30 mg / m 2 , for example, about 5 - 30 mg / m 2 , 5 - 25 mg / m 2 , 5 - 20 mg / m 2 , 5 - 15 mg / m 2 or 5 - 10 mg / m 2 and applied.

[0099] The lubricant on the surface of the outer substrate resin layer 1 may be a lubricant exuded from the substrate resin layer containing the lubricant, or may be a lubricant applied to the surface of the outer substrate resin layer 1.

[0100] The thickness of the outer substrate resin layer 1 is not particularly limited as long as it can function as a substrate. When the outer substrate resin layer 1 is a resin composite film of two or more layers, the thickness of the resin films constituting each layer is, for example, about 2 - 30 μm respectively, for example, 5 - 30 μm, 5 - 25 μm, 10 - 30 μm, 15 - 30 μm, 20 - 30 μm, for example, 2 μm, 5 μm, 10 μm, 15 μm, 18 μm, 20 μm, 23 μm, 25 μm, 28 μm, 30 μm.

[0101] In the present disclosure, the outer base resin layer 1 may be a single-layer or multi-layer composite film formed of one or more materials among polymer materials such as inflation nylon, simultaneously or non-simultaneously biaxially stretched nylon, simultaneously or non-simultaneously biaxially stretched polyethylene terephthalate (PET), simultaneously or non-simultaneously biaxially stretched polybutylene terephthalate (PBT), and polyimide (PI). The outer base resin layer 1 can be adhered to the intermediate metal layer 5 by one or a combination of extrusion, coating, lamination, and thermal bonding. The total thickness of the outer base resin layer 1 is 5 to 35 μm. When the total thickness of the base resin layer 1 is within the above range, it not only has better formability and insulation but also improved flexibility. If the thickness is less than 5 μm, the formability and insulation are relatively poor. Also, if it exceeds 35 μm, the total thickness of the metal composite film is too thick, and the flexibility, which is an advantage of the metal composite film, deteriorates.

[0102] Outer layer adhesive layer 2: In the packaging material for a lithium-ion battery of the present disclosure, when the outer base resin layer 1 and the intermediate metal layer 5 are laminated, the outer layer adhesive layer 2 is provided. The outer layer adhesive layer 2 is a layer formed to improve the adhesiveness between the outer base resin layer 1 and the intermediate metal layer 5.

[0103] The outer layer adhesive layer 2 is formed of a binder that can adhere the outer base resin layer 1 and the intermediate metal layer 5. The binder for forming the outer layer adhesive layer 2 is not limited. For example, it may be a two-component curable binder (two-component binder), or further, a one-component curable binder (one-component binder). Also, the binder used when forming the outer layer adhesive layer 2 may be any one of a chemical reaction type, a solvent evaporation type, a hot melt type, a hot press type, etc. Further, the outer layer adhesive layer 2 may be a single layer or multiple layers.

[0104] The outer adhesive layer 2 is a two-component polyurethane adhesive formed from a polyester polyol and a polyurethane-modified polyol or the like as the diol main agent, and an aromatic or aliphatic isocyanate as the curing agent. The curing agent can be selected according to the functional groups of the adhesive component, and is preferably selected from, for example, polyfunctional epoxy resins, polymers containing methanesulfonic acid, primary amines, polyamine resins, inorganic acids, and the like. In addition, the main agents used in the outer adhesive layer are polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene isophthalate, and copolyester; polyether resins; polyurethane resins; epoxy resins; phenolic resins; polyamide resins such as nylon 6, nylon 66, nylon 12, and copolyamide; polyolefin resins such as polyolefin, cyclic polyolefin, acid-modified polyolefin, and acid-modified cyclic polyolefin; polyvinyl acetate; cellulose; (methyl)acrylic resins; polyimide resins; polycarbonates; amino resins such as urea resins and melamine resins; rubbers such as chloroprene rubber, nitrile rubber, and styrene-butadiene rubber; and silicone resins. These adhesive components may be used alone or in combination of two or more.

[0105] A further alternative combination of the outer adhesive layer 2 in the present disclosure is one or two of a binary or polyvalent polyester and a polyurethane-modified polyester and an isocyanate. The isocyanate is not particularly limited to a compound having two or a large number of isocyanate groups in the molecule. For example, a mixture of one or more of polymers such as isophorone diisocyanate (IPDI), toluene diisocyanate (TDI), diphenylmethane-4,4 , -diisocyanate (MDI), and 1,6-hexamethylene diisocyanate (HDI).

[0106] In addition, as long as it does not affect the adhesiveness, other components may be added to the outer adhesive layer 2, and it can include a colorant, a thermoplastic elastomer, a thickener, a filler, and the like. By including a colorant in the outer adhesive layer 2, the packaging material for lithium-ion batteries can be colored. As the colorant, colorants such as pigments and dyes can be used. Also, one type of colorant may be used, or two or more types may be mixed and used.

[0107] The type of the pigment is not particularly limited as long as it does not impair the adhesiveness of the outer adhesive layer 2. As the organic pigment, for example, pigments such as azo-based, phthalocyanine-based, quinacridone-based, anthraquinone-based, dioxazine-based, indigoid thioindigo-based, perylene-based, and isoindoline-based can be used, and as the inorganic pigment, pigments such as carbon black-based, titanium oxide-based, cadmium-based, lead-based, and isoindoline-based can be used.

[0108] For example, the colorant is selectively carbon black so that the appearance of the packaging material for lithium-ion batteries becomes black.

[0109] The average particle size of the pigment is not particularly limited, and about 0.05 to 5 μm can be selected. For example, 0.08 to 5 μm, 0.1 to 4 μm, 0.5 to 3 μm, 1 to 2 μm, 0.05 to 4 μm, or 0.05 to 3 μm, for example, 0.05 μm, 0.060 μm, 0.07 μm, 0.08 μm, 0.1 μm, 1.2 μm, 1.4 μm, 1.6 μm, 1.8 μm, 2 μm, 3 μm, 4 μm, 5 μm, for example, about 0.08 to 2 μm. Also, the average particle size of the pigment is the median particle size measured by a laser diffraction / scattering type particle size distribution measuring device.

[0110] The pigment content in the outer adhesive layer 2 is not particularly limited as long as the packaging material for lithium-ion batteries is colored. For example, it is about 5 to 60%, for example, 10 to 40%.

[0111] The thickness of the outer adhesive layer 2 is not particularly limited as long as it can adhere the outer base resin layer 1 and the intermediate metal layer 3. As a selectable range, it can be about 1 to 10 μm, for example, it can be 1 to 5 μm, 3 to 10 μm or 3 to 8 μm, and for example, it can be 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm. Optionally, the thickness of the outer adhesive layer 2 is about 2 to 5 μm.

[0112] Coloring layer 3: The coloring layer 3 is a layer provided between the outer base resin layer 1 and the intermediate metal layer 5 as required. The colored metal composite film may be formed directly by adding a pigment to the outer adhesive layer 2, or the coloring layer 3 may be formed between the outer base resin layer 1 and the outer adhesive layer 2. Also, the coloring layer 3 may be provided outside the outer base resin layer 1.

[0113] The coloring layer 3 can be formed, for example, by applying an ink containing a coloring agent to the surface of the outer base resin layer 1, the surface of the outer adhesive layer 2 or the surface of the intermediate metal layer 5. As the coloring agent, coloring agents such as pigments and dyes can be used. Also, only one kind of coloring agent may be used, or two or more kinds may be mixed and used.

[0114] As an example of the coloring agent contained in the coloring layer 3, reference can be made to the example of the outer adhesive layer 2.

[0115] Intermediate metal layer 5: In the exterior material for a lithium ion battery, the intermediate metal layer 5 is at least a barrier layer capable of suppressing the intrusion of moisture.

[0116] As the metal material used for the intermediate metal layer 5, in some embodiments, it may be an aluminum alloy, stainless steel, titanium steel, nickel-plated iron plate, etc. When used as a metal foil, it may be one layer or multiple layers. Optionally, at least one of aluminum alloy foil, nickel-plated iron plate and stainless steel foil is included.

[0117] Generally, the selection of the aluminum alloy foil is as follows. From the perspective of improving the formability of the packaging material for lithium-ion batteries, the aluminum alloy foil is more selectively a soft aluminum alloy foil composed of, for example, annealed aluminum alloy, etc. From the perspective of further improving the formability, the aluminum alloy foil is selectively an aluminum alloy foil containing iron. If necessary to withstand electrolytes, etc., silica, magnesium, etc. may be added.

[0118] Examples of the stainless steel foil include austenitic, ferritic, austenitic-ferritic, martensitic, precipitation-hardening stainless steel foils, etc. From the perspective of providing a packaging material for lithium-ion batteries with better formability, the stainless steel foil is selectively composed of austenitic stainless steel.

[0119] Examples of the austenitic stainless steel constituting the stainless steel foil include SUS304, SUS301, SUS316L, etc., among which, particularly selectively, is SUS304.

[0120] When the intermediate metal layer 5 is a metal foil, the thickness only needs to be sufficient to function as an intermediate metal layer that at least suppresses the intrusion of moisture. For example, it can be about 9 to 200 μm, for example, 9 to 150 μm, 9 to 100 μm or 9 to 50 μm, for example, 9 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 100 μm, 150 μm, 200 μm. The upper limit of the thickness of the intermediate metal layer 3 is, for example, about 100 μm or less, for example, about 50 μm or less, for example, 50 μm, 45 μm, 40 μm, 35 μm, 30 μm, 25 μm, 20 μm, 15 μm.

[0121] Anticorrosion layer 6: The anticorrosion layer 6 in the packaging material for lithium-ion batteries avoids the corrosion of the surface of the intermediate metal layer 5 caused by hydrogen fluoride generated by the reaction of the electrolyte and moisture, prevents the separation of the intermediate metal layer 5 and the heat-sealing resin layer 8, maintains the uniformity of the surface of the intermediate metal layer 5, and reduces the change in adhesiveness (wettability). It has the effect of preventing delamination between the intermediate metal layer 5 and the heat-sealing resin layer 8 in the metal composite film. Optionally, an anticorrosion liquid is applied to at least the surface of the intermediate metal layer 5 on the side opposite to the outer base resin side to form the anticorrosion layer. Optionally, anticorrosion layers are formed on both sides of the intermediate metal layer 5. By forming the anticorrosion layer on the surface of the intermediate metal layer 5 in contact with the outer base resin layer 1, the uniformity of the surface of the intermediate metal layer 5 is stabilized, the change in adhesiveness (wettability) is reduced, and long-term storage in a high-temperature and high-humidity environment becomes possible. It has the effect of preventing delamination between the outer base resin layer 1 and the intermediate metal layer 5 in the metal composite film. The anticorrosion liquid of the present disclosure is mainly an aqueous solution composed of a trivalent chromium compound, an inorganic acid, a fluoride, and an organic resin. Among them, the proportions of the trivalent chromium compound, the inorganic acid, the fluoride, the organic resin, and water are 1.9 - 6%, 0.3 - 6%, 0 - 10%, 0.6 - 6%, and 82 - 97.2% respectively. The trivalent chromium compound in the anticorrosion liquid consists of at least one of chromium nitrate, chromium phosphate, and chromium chloride. The inorganic acid consists of at least one of nitric acid and phosphoric acid. The fluoride consists of at least one of chromium fluoride and aluminum fluoride. The organic resin consists of a polyacrylic acid-based resin and polyvinyl alcohol. The polyacrylic acid-based resin is one or more of copolymers such as polyacrylic acid, polymethyl acrylate, acrylic acid, and maleic acid, copolymers of acrylic acid and styrene, and derivatives such as sodium salts and ammonium salts thereof. First, a degreasing treatment is performed on at least the side of the intermediate metal layer 5 in contact with the heat-sealing resin layer by treatment methods such as the alkali immersion method, the electrolytic cleaning method, the acid cleaning method, the electrolytic acid cleaning method, the oxygen activation method, and the heat treatment (annealing treatment) during rolling. Next, the anticorrosion liquid of the present disclosure is used and applied to the surface of the intermediate metal layer 5 by methods such as the bar coating method, the roll coating method, the gravure coating method, and the dipping method, and a high-temperature chemical reaction is carried out to act. The intermediate metal layer 5 coated with the anticorrosion liquid is heat-treated at a high temperature of 130 - 200°C for 0.5 - 5 minutes to form the anticorrosion layer 6.

[0122] The thickness of the anticorrosive layer 6 is not particularly limited, but from the viewpoint of the adhesive strength between the intermediate metal layer 5 and the heat-sealing resin layer 8, for example, it is 1 nm to 3.0 μm, and for example, it is 1 nm to 1.5 μm. Further, the chromium content in the anticorrosive layer 6 is between 8 and 50 mg / m 2 and, for example, between 10 and 30 mg / m 2 .

[0123] Inner layer adhesive layer 7: In the packaging material for a lithium-ion battery of the present disclosure, the inner layer adhesive layer 7 is an intermediate layer provided to firmly adhere the intermediate metal layer 5 and the heat-sealing resin layer 8.

[0124] The inner layer adhesive layer 7 is formed of a resin capable of adhering the intermediate metal layer 5 and the heat-sealing resin layer 8. The above heat-sealing resin layer 8 may use polyolefin, cyclic polyolefin, etc., and may also use modified polyolefin-based resins such as carboxylic acid-modified polyolefin, carboxylic acid-modified cyclic polyolefin, methacrylic acid-modified polyolefin, acrylic acid-modified polyolefin, crotonic acid-modified polyolefin, imide-modified polyolefin. From the viewpoint of enhancing the adhesiveness between the intermediate metal layer and the inner heat-sealing resin layer, the modified polyolefin is preferably a modified polyolefin resin such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, polyamide. The resin constituting the inner layer adhesive layer may or may not contain a polyolefin main chain, and preferably contains a polyolefin main chain. Whether the resin constituting the inner layer adhesive layer 7 contains a polyolefin main chain can be analyzed by, for example, infrared spectroscopy, gas chromatography-mass spectrometry, etc., and the analysis method is not particularly limited. The polyolefin and its modified resin used for the inner layer adhesive are the same as the resin used for the heat-sealing resin layer 8, and are polypropylene resin or a copolymer of propylene and ethylene.

[0125] From the perspective of the long-term use stability of the packaging material for lithium-ion batteries, the inner adhesive layer 7 may be a combination of a resin containing an acid-modified polyolefin and a curing agent. As the acid-modified polyolefin, optionally, it is a polyolefin modified with maleic anhydride or acrylic acid.

[0126] As the curing agent, it only needs to be a curing agent that cures the acid-modified polyolefin, and there is no particular limitation. Curing agents such as epoxy-based curing agents, polyfunctional isocyanate-based curing agents, carbodiimide-based curing agents, and oxazoline-based curing agents can be used.

[0127] As the epoxy-based curing agent, any compound having at least one epoxy group may be used, and there is no particular limitation. For example, epoxy resins such as bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, novolac glycidyl ether, glycerol polyglycidyl ether, and polyglycerol polyglycidyl ether are used.

[0128] As the polyfunctional isocyanate-based curing agent, any compound having two or more isocyanate groups in the molecule may be used, and there is no particular limitation. For example, components after polymerization or addition of substances such as isophorone diisocyanate (PDI), hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI), and diphenylmethane diisocyanate (MDI), or reactants of such mixtures with other polymers are used.

[0129] As the carbodiimide-based curing agent, any compound having at least one carbodiimide group (-N=C=N-) in the molecule may be used, and there is no particular limitation. Optionally, it is a polycarbodiimide compound having at least two or more carbodiimide groups.

[0130] As the oxazoline-based curing agent, any compound having an oxazoline skeleton may be used, and there is no particular limitation.

[0131] From the perspective of improving the adhesiveness between the inner adhesive layer 7 and the heat-sealing resin layer 8, etc., the curing agent may be composed of two or more compounds.

[0132] Regarding the thickness of the inner adhesive layer 7, it only needs to have the function as an adhesive layer, and there is no particular limitation. For example, it is about 1 to 80 μm, for example, 10 to 80 μm, 20 to 80 μm, 20 to 70 μm or 20 to 60 μm. In some embodiments, the thickness of the inner adhesive layer 7 is, for example, about 1 to 50 μm.

[0133] The main component of the inner adhesive layer 7 in the present disclosure is a single-layer or two-layer or more film layer formed from one or a mixture of two or more of modified polyolefin resin, polyolefin resin, polypropylene block copolymer resin (B-PP) with a polypropylene (PP) content exceeding 50%, polypropylene random copolymer resin (R-PP), and homopolypropylene resin (H-PP).

[0134] When laminating the intermediate metal layer 5 and the heat-sealing resin layer 8, the solution-type inner adhesive layer 7 method or the hot-melt type inner adhesive resin layer 7 method may be used for the inner adhesive layer 7.

[0135] The solution-type inner adhesive layer 7 uses an acid-modified polyolefin resin as the main agent and one or more of isocyanate, epoxy resin, or oxazoline-based compounds as curing agents, or an amine compound such as triethylamine or N,N-dimethylethanolamine as the curing agent. After dissolving in at least one or more solvents such as water, ethanol, isopropanol, ethyl acetate, methyl ethyl ketone, toluene, and methylcyclohexane, it is uniformly applied to the surface of the corrosion-treated metal, heated to volatilize the solvent, and the thickness of the inner adhesive layer 7 is achieved to a desired effect, for example, about 1 to 10 μm, and further, for example, 1 to 5 μm. If the thickness of the inner adhesive layer 7 is within the above range, not only can an effective adhesive force between the intermediate metal layer 5 and the heat-sealing resin layer 8 be ensured, but also when reacting with the curing agent, the flexural resistance and flexibility of the metal composite film are improved, the risk of crack generation due to bending is avoided, and the peeling between the intermediate metal layer 5 and the heat-sealing resin layer 8 is effectively prevented. When the thickness is less than 1 μm, the thickness becomes thin, the adhesive force between the intermediate metal layer 5 and the heat-sealing resin layer 8 is reduced, and the adhesiveness becomes a problem. When the thickness exceeds 10 μm, the adhesiveness is not a problem, but when reacting with the curing agent, a hard resin layer is formed, the flexural resistance becomes poor, the flexibility of the metal composite film is reduced, the risk of generating cracks due to bending appears, and the intermediate metal layer 5 and the heat-sealing resin layer 8 may be peeled off. The melting point of the acid-modified polyolefin resin in the solution-type inner adhesive 7 is in the range of 60 to 155 °C, the weight average molecular weight is in the range of 10,000 to 150,000, and the acid value of the solution-type inner adhesive is in the range of 0.5 to 200 mgKOH / g. When using an amine compound as the curing agent, the solution-type inner adhesive mainly consists of an acid-modified polyolefin resin and an amine compound, and the ratio of the acid-modified polyolefin to the amine compound is 10:1 to 125:1, for example, 15:1 to 50:1. The acids used in the modified polyolefin are maleic acid, fumaric acid, methacrylic acid, etc., and the amine compound is at least one of triethylamine or N,N-2-methylethanolamine.The acid-modified polyolefin resin is a single layer or multiple layers composed of a mixture of one or more of polypropylene block copolymer resin (B-PP), polypropylene random copolymer resin (R-PP), and homopolypropylene resin (H-PP), in which the content of polypropylene having a melting point of 110 °C or higher exceeds 50%.

[0136] If the melting point is within the above range, not only can the peeling between the intermediate metal layer 5 and the heat-sealing resin layer 8 at high temperatures be avoided, but also when reacting with the curing agent, the flexibility and bending resistance of the metal composite film are improved, the generation of cracks due to bending is effectively prevented, and the peeling between the intermediate metal layer 5 and the heat-sealing resin layer 8 is avoided. When the melting point is 60°C or lower, the heat resistance is low, and there is a possibility of peeling between the intermediate metal layer 5 and the heat-sealing resin layer 8 at high temperatures. Furthermore, when it exceeds 155°C, although the heat resistance is relatively good, when reacting with the curing agent, a hard resin layer is formed and the bending resistance is poor, so the flexibility of the metal composite film is reduced, or cracks may occur due to bending, and the intermediate metal layer 5 and the heat-sealing resin layer 8 may be peeled off. If the average molecular weight is within the above range, not only can the thickness of the resin during heat sealing be ensured, but also the adhesion strength and sealing performance between the intermediate metal layer 5 and the heat-sealing resin layer 8 are effectively ensured, and the flexibility and bending resistance of the metal composite film are improved, the flexibility of the metal composite film is enhanced, or the generation of cracks due to bending is avoided, and the peeling between the intermediate metal layer 5 and the heat-sealing resin layer 8 is effectively avoided. When the weight average molecular weight is 10,000 or less, during heating, the fluidity of the resin is high, and during heat sealing, the thickness becomes extremely thin, and the adhesion strength between the intermediate metal layer 5 and the heat-sealing resin layer 8 becomes low (when a curing agent is added and reacted), and the sealing performance becomes a problem. When the weight average molecular weight exceeds 150,000, for the intermediate metal layer 5 and the heat-sealing resin layer 8 (when a curing agent is added and reacted), a hard resin layer is formed, the bending resistance becomes poor, the flexibility of the metal composite film is reduced, or cracks may occur due to bending, and the intermediate metal layer 5 and the heat-sealing resin layer 8 may be peeled off. If the acid value of the acid-modified polyolefin resin is within the above range, it can react sufficiently with the curing agent, the adhesiveness between the intermediate metal layer 5 and the heat-sealing resin layer 8 is ensured, and the flexibility and bending resistance of the metal composite film are ensured, or the generation of cracks due to bending is avoided, and the peeling between the intermediate metal layer 5 and the inner heat-sealing resin layer 8 is prevented. When the acid value of the acid-modified polyolefin resin is less than 0.5 mgKOH / g, the number of curing reaction points with the curing agent is small, and the adhesiveness between the intermediate metal layer 5 and the heat-sealing resin layer 8 becomes unstable.When the acid value exceeds 200 mgKOH / g, the curing reaction between the curing agent and the acid-modified polyolefin resin becomes too intense, a hard resin layer is formed, the flexural resistance deteriorates, the flexibility of the metal composite film is reduced, or cracks may occur due to bending, and the intermediate metal layer 5 and the inner heat-sealing resin layer 8 may be peeled off.

[0137] The inner layer adhesive layer 7 used for the intermediate metal layer 5 and the heat-sealing resin layer 8 may be a hot-melt type inner layer adhesive. The resin used for the hot-melt type inner layer adhesive layer 7 is an acid-modified polyolefin resin having a melting point of 135 to 165 °C and an MFR (230 °C) of 3 to 15 g / 10 min. The thickness of the formed inner layer adhesive layer 7 is 2 to 80 μm, for example, 5 to 50 μm. The degree of modification of the acid-modified polyolefin resin used for the hot-melt type inner layer adhesive is 1 to 15%, for example, the degree of modification is 1 to 10%, 5 to 15%, 5 to 10%, for example, 1%, 3%, 5%, 7%, 9%, 10%, 12%, 14%, 15%. In some embodiments, the degree of modification is, for example, 3 to 12%. When the melting point of the acid-modified polyolefin resin is within the above range, it is ensured that the resin has good fluidity during heating, and the adhesion strength between the intermediate metal layer 5 and the heat-sealing resin layer 8 is well ensured during pressure heat sealing. Furthermore, the sealing performance can be improved, and the adhesion ability between the hot-melt type inner layer adhesive and the intermediate metal layer 5 is effectively improved. When the melting point of the acid-modified polyolefin resin is 135 °C or lower, the resin fluidity becomes high due to heating, and the thickness becomes extremely thin during pressure heat sealing, resulting in a low adhesion strength between the intermediate metal layer 5 and the heat-sealing resin layer 8, and the sealing performance becomes a problem. When the melting point is 165 °C or higher, the fluidity is relatively low during pressure heat sealing, and the heat resistance becomes high. However, when compounding with the intermediate metal layer 5, the heat shrinkage amount increases, the internal stress increases, and the adhesion ability between the hot-melt type inner layer adhesive and the intermediate metal layer 5 decreases. Therefore, during the long-term storage process, there is a risk of peeling from the intermediate metal layer 5. In addition, due to the heating during heat sealing, further heat shrinkage occurs, the adhesion force with the intermediate metal layer 5 is reduced, the sealing strength is lowered, and the sealing performance becomes a major problem. When the MFR (230 °C) of the acid-modified polyolefin resin is less than 3 g / 10 min, the extrusion film-forming property is likely to become unstable when extruded onto the intermediate metal layer 5 after hot melting. When the MFR (230 °C) of the acid-modified polyolefin resin is higher than 15 g / 10 min, the resin fluidity becomes high due to heating, and the thickness becomes extremely thin during pressure heat sealing, resulting in a low adhesion strength between the intermediate metal layer 5 and the heat-sealing resin layer 8, and the sealing performance becomes a problem.When the thickness of the hot-melt type inner adhesive layer 7 is less than 2 μm, when it is combined with the intermediate metal layer 5, the amount of thermal shrinkage is too large, so it cannot absorb the thermal shrinkage. Therefore, due to the increase in internal stress, the bonding force with the intermediate metal layer 5 decreases. During long-term storage, there is a risk of peeling from the intermediate metal layer 5. When the thickness of the hot-melt type inner adhesive layer 7 exceeds 80 μm, although there is no problem with physical properties, since it causes an increase in production cost, it is better to avoid using it. When the degree of modification of the hot-melt type inner adhesive layer 7 is less than 1%, the adhesiveness with the intermediate metal layer 5 becomes unstable. When the degree of modification exceeds 15%, although there is no problem with physical properties, since it causes an increase in production cost, it is better to avoid this.

[0138] Specific embodiments of the present disclosure disclose the composite process of the metal composite film as follows: Degreasing treatment of the intermediate metal layer 5: The surface wettability of the intermediate metal layer 5 is 65 dyn / cm or more, for example, 70 dyn / cm or more, or the angle of the titration contact angle of distilled water is 15 degrees or less, for example, 10 degrees or less. When the wettability or surface water contact angle of the intermediate metal layer 5 exceeds a predetermined range, it is shown that the rolling oil in the manufacturing stage may still remain on the metal. Therefore, the interfacial adhesion ability formed between the anticorrosive layer 6, the intermediate metal layer 5 and the hot-melt resin layer 8 becomes poor, and during long-term storage of the battery, there is a risk of peeling between the intermediate metal layer 5 and the hot-melt resin layer 8, and liquid leakage of the battery is likely to occur. As a preventive measure, annealing treatment at 150 °C or higher may be performed, or degreasing may be performed by plasma, corona method, or alkaline solution. The method of alkaline degreasing is to immerse the metal in an alkaline solution at 50 - 65 °C, treat it for a certain time, then wash it twice with deionized water, and then dry it to obtain the degreased metal. Formation of the anticorrosive layer 6 on the intermediate metal layer 5: After applying an anticorrosive liquid to the surface of the intermediate metal layer 5 on the side in contact with the hot-melt resin layer 8, heat treatment is performed at a high temperature for a certain time. Formation and Lamination of the Outer Adhesive Layer 2: A polyurethane-based adhesive dissolved in an organic solvent is applied between the intermediate metal layer 5 and the outer base resin layer 1, heated at a constant temperature for a certain period of time to volatilize the organic solvent, thereby forming the outer adhesive layer 2. In some embodiments, the outer base resin layer 1, the outer adhesive layer 2, and the intermediate metal layer 5 are laminated at a constant temperature and pressure, and after being stored at a constant temperature for a certain period of time, the outer adhesive layer 2 is subjected to a curing reaction to obtain a composite resin layer composed of the outer base resin layer 1, the outer adhesive layer 2, and the intermediate metal layer 5. When no outer adhesive is used for the lamination of the outer base resin layer 1 and the intermediate metal layer 5, the intermediate metal layer 5 and the outer base resin layer 1 are laminated by heating and pressing. If the outer base resin layer is formed into a film by heat treatment, ultraviolet treatment, or electron beam treatment, a composite resin layer composed of the outer base resin layer 1 and the intermediate metal layer 5 can be obtained. Lamination of the Heat-Welded Resin Layer 8: A composite film composed of the outer base resin layer 1 and the intermediate metal layer 5 can be preferably selected and laminated with the heat-welded resin layer 8 by different lamination methods, which are exemplified as follows: a. Dry Lamination Method: A solution-type inner adhesive composed of a main agent, a curing agent, and an organic solvent is applied to the corrosion-proof surface of the intermediate metal layer 5 of the composite film composed of the outer base resin layer 1 and the intermediate metal layer 5. The solution-type inner adhesive is dried to form the inner adhesive layer 7. Then, after heat-laminating with the adhesive surface of the heat-welded resin layer 8 at a constant temperature and pressure, an aging treatment is performed to form a laminated product of the outer base resin layer / outer adhesive layer / intermediate metal layer / inner adhesive layer / heat-welded resin layer. Optionally, a corona treatment is performed in advance on the adhesive surface of the heat-welded resin layer 8 that contacts the inner adhesive layer 7. Also, an aging treatment can be performed at a temperature not exceeding 60°C above the melting point of the inner adhesive layer 7. b. Melt Extrusion Method: The resin for the heat-melt type inner adhesive forms a heat-melt type inner adhesive layer 7 with a certain thickness on the corrosion-proof surface of the intermediate metal layer 5 by melt extrusion. Also, heat lamination is performed on the surface of the inner adhesive layer 7 and the adhesive surface of the heat-welded resin layer 8 to form a laminated product of the outer base resin layer / outer adhesive layer / intermediate metal layer / inner adhesive layer / heat-welded resin layer. To improve the peel strength between the intermediate metal layer 5 and the heat-welded resin layer 8, a heat treatment can be performed at a temperature not exceeding 60°C above the melting point of the inner adhesive layer 7. c. Melt extrusion method: The hot-melt inner layer adhesive layer 7 and the heat-sealing resin layer 8 are formed into a composite product of outer substrate resin layer / outer layer adhesive layer / intermediate metal layer / inner layer adhesive layer / heat-sealing resin layer by co-extrusion. After performing an anti-corrosion treatment on the surface of the intermediate metal layer 5 in contact with the inner layer adhesive layer 7, in order to improve the peel strength between the intermediate metal layer 5 and the heat-sealing resin layer 8, heat treatment can be performed at a temperature not exceeding 60°C above the melting point of the inner layer adhesive layer 7. d. Thermal bonding method: A resin base and a curing agent with a melting point of 100°C or higher are dissolved in an aqueous or organic solvent to form an aqueous solution type inner layer adhesive. It is applied to the anti-corrosion treatment surface of the metal layer of the composite layer composed of the outer substrate resin layer 1 and the intermediate metal layer 5, and the solution type inner layer adhesive is dried to form the inner layer adhesive layer 7. At a certain temperature and pressure, it is thermally combined with the adhesive surface of the heat-sealing resin layer 8 to form a composite product of outer substrate resin layer / outer layer adhesive layer / intermediate metal layer / inner layer adhesive layer / heat-sealing resin layer. In order to improve the peel strength between the intermediate metal layer 5 and the heat-sealing resin layer 8, heat treatment can be performed at a temperature not exceeding 60°C above the melting point of the inner layer adhesive layer 7. The heat-sealing resin layer 8 may be formed by an extrusion method or a thin film may be used. When using a thin film, optionally, a corona treatment is performed in advance on the adhesive surface of the heat-sealing resin layer 8 in contact with the inner layer adhesive layer 7.

[0139] Hereinafter, the present disclosure will be described in detail by examples.

[0140] In the following examples and comparative examples, the peel strength between the intermediate metal layer 5 and the heat-sealing resin layer 8 of the metal composite film finished product is measured by the following method: (1) Initial peel strength test The finished metal composite film was made into strip shape, the size of the sample strip was 100×15 mm, a peel test between the intermediate metal layer 5 and the heat-sealing resin layer 8 was carried out by a stretching test device, the 50 mm peeled thin film of the heat-sealing resin layer 8 was set on the upper clamp plate of the stretching and shrinking test device, the intermediate metal layer 5 was set on the lower clamp plate, and a T-peel with a peel angle of 180° was carried out at a stretching and shrinking speed of 50 mm / min to start measuring the peel strength between the intermediate metal layer 5 and the heat-sealing resin layer 8. The way to read the peel strength was to set the moving distance of the heat-sealing resin layer 8 and the intermediate metal layer 5 to 50 mm, and select the average value of the peel strength when the moving distance was between 10 and 40 mm. Parallel tests were carried out with 5 samples / group.

[0141] (2) Electrolyte resistance test without water The sample strip of the finished metal composite film (the size of the sample strip was 100×15 mm) was directly immersed in a mixed solvent of dimethyl carbonate (DMC): diethyl carbonate (DEC): ethylene carbonate (EC) with a molar ratio of 1:1:1 containing 1 mol / L of LiPF6, immersed at a temperature of 85 °C for 3 days, then taken out, washed with water for 15 min, the moisture on the surface of the sample strip was wiped off, and the peel strength between the intermediate metal layer 5 and the heat-sealing resin layer 8 was measured according to the initial peel strength test method of the finished product in (1).

[0142] (3) Electrolyte resistance test with water The metal composite film was cut into sample strips with a width of 15 mm and a length of 100 mm. After peeling 50 mm between the intermediate metal layer and the inner heat-sealing resin layer, it was immersed in a solvent of dimethyl carbonate (DMC): diethyl carbonate (DEC): ethylene carbonate (EC) with a molar ratio of 1:1:1 containing 1 mol / L of LiPF6, and water accounting for 1000 PPM of the total mass of the electrolyte was added. After immersing at a temperature of 85 °C for 3 days, it was taken out, washed with water for 15 min, and without wiping off the moisture, with some moisture remaining between the pre-peeled intermediate metal layer 5 and the heat-sealing resin layer 8, starting from the pre-peeled position, the peel strength between the intermediate metal layer 5 and the heat-sealing resin layer 8 was measured according to the initial peel strength test method of the finished product in (1).

[0143] The realization process of specific embodiments of the present disclosure is provided as follows: 1. Lamination The metal composite film is composed of an outer substrate resin layer / outer layer adhesive layer (3 μm) / intermediate metal layer / inner layer adhesive layer / heat-sealing resin layer. The thicknesses of the outer substrate resin layer 1 and the intermediate metal layer 5 can be changed according to respective embodiments.

[0144] The lamination method is as follows: Corona treatment was performed on the thin film of the outer substrate resin layer 1 in contact with the outer layer adhesive layer 2. On one side of a metal foil (such as aluminum foil, nickel-plated iron foil, or stainless steel foil), a two-component polyurethane adhesive (a polyurethane-modified polyester polyol or a polyester polyol and an aromatic isocyanate compound) mixed at different NCO / OH ratios (in this specification, both "NCO / OH ratio" or "NCO / OH ratio" refer to the equivalent ratio of NCO / OH) was applied to form an adhesive layer 2 (3 μm) on the intermediate metal foil. After thermally laminating the outer layer adhesive layer 2 and the thin film of the outer substrate resin layer 1 on the intermediate metal foil, aging treatment was performed at a temperature of 80 °C for 3 days to form the outer substrate resin layer / outer layer adhesive layer (3 μm) / intermediate metal layer. Anticorrosion treatment was performed in advance on both sides of the intermediate metal layer 5.

[0145] The outer layer adhesive layer 2 was formed on one side of the intermediate metal foil by three methods, which are as follows respectively: A-1: An amorphous polyester polyol with a weight average molecular weight of 80,000, a Tg of 79 °C, and a hydroxyl value of 16 mg KOH / g and an amorphous polyester polyol with a weight average molecular weight of 6,500, a Tg of -3 °C, and a hydroxyl value of 10 mg KOH / g were mixed at a weight ratio of 10:5, and toluene diisocyanate (TDI) was added to form a mixed outer adhesive liquid with an NCO / OH ratio of 21.0. A-2: An amorphous polyester polyol with a weight average molecular weight of 5000, a Tg of 50 °C, and a hydroxyl value of 25 mg KOH / g and an amorphous polyester polyol with a weight average molecular weight of 20000, a Tg of -17 °C, and a hydroxyl value of 8 mg KOH / g are mixed at a weight ratio of 3:2, and toluene diisocyanate (TDI) is added to form a mixed outer layer adhesive solution with an NCO / OH ratio of 6.2. A-3: An amorphous polyurethane-modified polyester polyol with a weight average molecular weight of 40000, a Tg of -3 °C, and a hydroxyl value of 3 mg KOH / g, an amorphous polyester polyol with a weight average molecular weight of 15000, a Tg of -10 °C, and a hydroxyl value of 15 mg KOH / g, and an amorphous polyester polyol with a weight average molecular weight of 3000, a Tg of 60 °C, and a hydroxyl value of 50 mg KOH / g are mixed at a weight ratio of 10:10:0.1, and toluene diisocyanate (TDI) is added to form a mixed outer layer adhesive solution with an NCO / OH ratio of 4. In Examples 1, 2, 7, and Comparative Examples 1, 2, and 3, the method of the outer layer adhesive A-1 was used. In Examples 3 and 4, the method of the outer layer adhesive A-2 was used. In Examples 5 and 6, the method of the outer layer adhesive A-3 was used.

[0146] Anticorrosion treatment was performed in advance on both sides of the metal layer.

[0147] The anticorrosion agents used in Examples 1, 2, 5, 6 and Comparative Examples 1 and 2 are all aqueous solutions composed of trivalent chromium compounds - chromium nitrate, inorganic acids - phosphoric acid and nitric acid, and organic resins - polyvinyl alcohol resin and polyacrylic resin. The anticorrosion agent used in Example 3 is an aqueous solution composed of trivalent chromium compounds - chromium phosphate, inorganic acids - nitric acid, and organic resins - polyacrylic resin. The anticorrosion agent used in Example 4 is an aqueous solution composed of trivalent chromium compounds - chromium nitrate, inorganic acids - phosphoric acid, and organic resins - polyacrylic resin.

[0148] In Examples 1 to 6 and Comparative Examples 2 and 3, they were uniformly coated on both sides of the metal foil by a coating roll at a certain mixing ratio, and then baked at 190 °C for 2 min. The wet coating amount of the anticorrosion layer treatment liquid is 5 g / m 2 is.

[0149] In Example 7, a certain proportion of fluoride-chromium fluoride was added to the anticorrosive agent of Example 4, uniformly applied to both sides of the metal foil by a coating roll at a certain compounding ratio, and then baked at 190 °C for 2 min.

[0150] In Comparative Example 1, an aqueous solution composed of a trivalent chromium compound-chromium phosphate, an inorganic acid-phosphoric acid, a fluoride, and an aminophenol polymer was uniformly applied to both sides of the metal foil by a coating roll at a certain compounding ratio, and then baked at 190 °C for 2 min.

[0151] Finally, there are the following six methods for laminating the inner adhesive layer 7 and the heat-sealing resin layer 8 on the metal surface of the semi-finished product, i.e., the outer base resin layer / outer layer adhesive layer (3 μm) / intermediate metal layer: (1) Lamination method of solution-type inner adhesive layer B-1-a: A solution-type mixture formed at a solid ratio of 20:1 by a maleic anhydride-modified polypropylene solution with a weight-average molecular weight of 80,000, a melting point of 80 °C, and an acid value of 2 mg KOH / g and an aromatic isocyanate (PDI, dimethyl isocyanate) solution was applied to the anticorrosive-treated intermediate metal surface in contact with the heat-sealing resin layer 8 of the composite film to which the outer base resin layer 1 was laminated. After drying, an adhesive layer B-1 with a thickness of 4 μm was formed. Then, at a temperature of 80 °C, it was thermally laminated with the adhesive surface of the 25-μm heat-sealing resin, and further aged at a temperature of 60 °C for 7 days to form a composite finished product of outer base resin layer / outer layer adhesive layer (3 μm) / intermediate metal layer / inner adhesive layer / heat-sealing resin layer (25 μm). The adhesive surface of the three-layer heat-sealing resin layer in contact with the inner adhesive layer 7 was pre-treated with corona.

[0152] The three-layer structure of the heat-sealing resin is as follows: Resin layer in contact with the inner adhesive layer 7: It is a layer made of a polypropylene random copolymer with a melting point of 145 °C and an MFR (230 °C) of 7.5 g / 10 min. Intermediate resin layer: A mixture layer formed from 40% by weight of a polypropylene block copolymer having a melting point of 162°C and an MFR (230°C) of 2 g / 10 min, 40% by weight of a polypropylene block copolymer having a melting point of 160°C and an MFR (230°C) of 5 g / 10 min, and 20% by weight of a crystalline polymer elastomer composed of ethylene-propylene having a melting point of 130°C, an MFR (230°C) of 9.5 g / 10 min, and a density of 0.91 g / cm 3 is a mixture layer formed from a crystalline polymer elastomer composed of ethylene-propylene having a melting point of 130°C, an MFR (230°C) of 9.5 g / 10 min, and a density of 0.91 g / cm Innermost layer resin layer: A layer made of a polypropylene random copolymer having a melting point of 145°C and an MFR (230°C) of 7.5 g / 10 min, The thickness ratio of the three layers of resin from the contact layer of the inner layer adhesive layer 7 to the innermost layer in the heat-sealing resin layer 8 is 1:8:1.

[0153] (2) Laminating method for the solution-type inner layer adhesive layer B-1-b: A solution-type mixture formed at a solid ratio (i.e., mass ratio) of 10:1 from a maleic anhydride-modified polypropylene solution having a weight-average molecular weight of 60,000, a melting point of 75°C, and an acid value of 5 mg KOH / g and an epoxy resin (bisphenol F diglyceryl ether) solution is applied to the surface of the corrosion-protected intermediate metal layer 5 in contact with the heat-sealing resin layer 8 of the composite film to which the outer substrate resin is laminated. After drying, an adhesive layer B-1 with a thickness of 2 μm is formed. Then, at a temperature of 80°C, it is thermally laminated with the adhesive surface of 80 μm of heat-sealing resin, and further aged at a temperature of 80°C for 7 days to form a composite finished product of outer substrate resin layer / outer layer adhesive layer (3 μm) / intermediate metal layer / inner layer adhesive layer / heat-sealing resin layer (80 μm). The adhesive surface of the three-layer heat-sealing resin layer 8 in contact with the inner layer adhesive layer 7 was previously subjected to corona treatment.

[0154] The heat-sealing resin consists of three layers, and its structure is as follows: Resin layer in contact with the inner layer adhesive layer 7: A layer made of a polypropylene random copolymer having a melting point of 162°C and an MFR (230°C) of 5.5 g / 10 min, Intermediate resin layer: A mixture layer formed from 50% by weight of a polypropylene block copolymer having a melting point of 162°C and an MFR (230°C) of 2 g / 10 min, 20% by weight of a polypropylene random copolymer having a melting point of 155°C and an MFR (230°C) of 5 g / 10 min, 20% by weight of a polymer elastomer composed of propylene-butene having a melting point of 160°C, an MFR (230°C) of 9.5 g / 10 min, and a density of 0.87 g / cm 3 and 10% by weight of an amorphous propylene-based elastomer having an MFR (230°C) of 3 g / 10 min. Innermost layer resin layer: A layer made of a polypropylene random copolymer having a melting point of 145°C and an MFR (230°C) of 12 g / 10 min. The thickness ratio of the three layers of resin from the contact layer of the inner layer adhesive layer 7 to the innermost layer in the heat-sealing resin layer 8 is 3:6:1.

[0155] (3) Laminating method of the melt-type inner layer adhesive layer B-2-a: The melt-type resin used for the inner layer adhesive layer 7 is maleic anhydride-modified polypropylene. A pressure-sensitive adhesive layer with a thickness of 15 μm was formed on the corrosion-resistant treatment surface of the intermediate metal layer 5 in contact with the heat-sealing resin layer 8, and then it was laminated with a heat-sealing resin with a thickness of 30 μm. The inner layer adhesive layer 7 and the heat-sealing resin layer 8 were laminated on the corrosion-resistant treatment surface of the intermediate metal layer 5 in contact with the heat-sealing resin layer 8 by melt co-extrusion. The used inner layer adhesive layer 7 is composed of 60% (by weight) of a maleic anhydride-modified polypropylene random copolymer having a melting point of 140°C and an MFR (230°C) of 5 g / 10 min, 24% (by weight) of a copolymer elastomer of propylene and butene having a degree of modification of 10% with respect to the polypropylene random copolymer of maleic anhydride, a melting point of 160°C, an MFR (230°C) of 2.6 g / 10 min, and a density of 0.87 g / cm 3 and 8% (by weight) of a crystalline copolymer elastomer of ethylene and propylene having a melting point of 130°C, an MFR (230°C) of 9.5 g / 10 min, and a density of 0.91 g / cm 3 and 8% (by weight) of low-density polyethylene having a melting point of 105°C and an MFR (230°C) of 12 g / 10 min.

[0156] The heat-sealing resin layer 8 consists of two layers, and its structure is as follows: The resin layer in contact with the inner adhesive layer 7: A mixture layer formed from 62% of a polypropylene random copolymer having a melting point of 155 °C and an MFR (230 °C) of 4 g / 10 min, 33% of an amorphous propylene-based elastomer, and 5% of a low-density polyethylene having a melting point of 110 °C and an MFR (230 °C) of 7.5 g / 10 min, by weight ratio, The innermost resin layer: A layer made of a polypropylene random copolymer having a melting point of 155 °C and an MFR (230 °C) of 15 g / 10 min,

[0157] The thickness ratio of the resin layer in contact with the inner adhesive layer 7 to the innermost resin layer is 8:2. After laminating the intermediate metal layer 5 with the inner adhesive layer 7 and the heat-sealing resin layer 8, heat treatment was performed at a temperature of 180 °C for 2 s. In this way, a composite finished product of outer base material resin layer / outer adhesive layer (3 μm) / intermediate metal layer / inner adhesive layer (15 μm) / inner heat-sealing resin layer (30 μm) was formed.

[0158] (4) Laminating method of the melt-type inner adhesive layer B-2-b: The melt-type resin used for the inner adhesive layer 7 is methacrylic acid-modified polypropylene. An inner adhesive layer 7 with a thickness of 30 μm was formed on the corrosion protection-treated surface of the intermediate metal layer 5 in contact with the heat-sealing resin layer 8, and it was laminated with the heat-sealing resin layer 8 having a thickness of 50 μm. The inner adhesive layer 7 and the heat-sealing resin layer 8 were laminated on the corrosion protection-treated surface of the intermediate metal layer 5 in contact with the heat-sealing resin layer 8 by melt co-extrusion. The used inner adhesive layer 7 is a mixture consisting of 57% (by weight ratio) of a methacrylic acid-modified polypropylene random copolymer having a melting point of 155 °C and an MFR (230 °C) of 2.5 g / 10 min, 33% (by weight ratio) of an amorphous propylene-based copolymer elastomer having a degree of modification of 10% with respect to the polypropylene random copolymer of methacrylic acid and an MFR (230 °C) of 3 g / 10 min, and 10% (by weight ratio) of a low-density polyethylene having a melting point of 105 °C and an MFR (230 °C) of 15 g / 10 min.

[0159] The inner heat-sealing resin consists of two layers, and its structure is as follows: Resin layer in contact with the inner adhesive layer 7: A mixture layer formed from 60% of a polypropylene random copolymer having a melting point of 152 °C and an MFR (230 °C) of 3 g / 10 min, 15% of a copolymer elastomer of propylene and butene having a melting point of 160 °C, an MFR (230 °C) of 2.6 g / 10 min, and a density of 0.9 g / cm 3 and 17% of a crystalline copolymer elastomer of ethylene and propylene having a melting point of 130 °C, an MFR (230 °C) of 9.5 g / 10 min, and a density of 0.91 g / cm 3 and 8% of a low-density polyethylene having a melting point of 110 °C and an MFR (230 °C) of 7.5 g / 10 min, Innermost resin layer: A mixture layer composed of 30% of a polypropylene random copolymer having a melting point of 138 °C and an MFR (230 °C) of 15 g / 10 min, 30% of a polypropylene random copolymer having a melting point of 146 °C and an MFR (230 °C) of 7 g / 10 min, 30% of a copolymer elastomer of propylene and butene having a melting point of 160 °C, an MFR (230 °C) of 2.6 g / 10 min, and a density of 0.86 g / cm 3 and 10% of a low-density polyethylene having a melting point of 105 °C and an MFR (230 °C) of 12 g / 10 min, The thickness ratio of the resin layer in contact with the inner adhesive layer 7 to the innermost resin layer is 8:2.

[0160] After laminating the intermediate metal layer 5 with the inner adhesive layer 7 and the heat-sealing resin layer 8, heat treatment was performed at a temperature of 180 °C for 10 s. Thus, a laminated finished product of outer substrate resin layer / outer adhesive layer (3 μm) / intermediate metal layer / inner adhesive layer (30 μm) / heat-sealing resin layer (50 μm) was formed.

[0161] (5) Laminating method of the solution-type inner layer adhesive layer B-3-a: The inner layer adhesive layer 7 uses a solution-type inner layer adhesive, and a mixture of a maleic anhydride-modified polypropylene resin with a weight average molecular weight of 100,000, a melting point of 135 °C, and an acid value of 2 mg KOH / g and an inner layer adhesive of an epoxy resin is uniformly applied to the surface of the corrosion-protected intermediate metal layer 5 of the composite film in contact with the heat-sealing resin layer 8 to which the outer base resin layer 1 is laminated, dried at a temperature of 150 °C for 2 min, and an adhesive layer B-3-a with a thickness of 2 μm is formed. A 40-μm three-layer heat-sealing resin thin film is laminated to the inner layer adhesive layer 7 by melt extrusion and further heat-treated at a temperature of 160 °C for 30 s. Thus, a composite finished product of outer base resin layer / outer layer adhesive layer (3 μm) / intermediate metal layer / inner layer adhesive layer (2 μm) / heat-sealing resin layer (40 μm) is formed.

[0162] The three-layer structure of the heat-sealing resin is as follows: Resin layer in contact with the inner layer adhesive layer 7: A layer composed of 65% of a maleic anhydride-modified polypropylene random copolymer with a melting point of 140 °C and an MFR (230 °C) of 5 g / 10 min (acid modification degree of 10%) and 35% of a mixture of amorphous propylene-based elastomers with an MFR (230 °C) of 3 g / 10 min by weight ratio. Intermediate resin layer: A mixture layer formed from 55% of polypropylene with a melting point of 160 °C and an MFR (230 °C) of 3.5 g / 10 min, 40% of a polypropylene block copolymer with a melting point of 130 °C, an MFR (230 °C) of 9.5 g / 10 min, and a density of 0.91 g / cm 3 and 20% of a crystalline polymer elastomer composed of ethylene-propylene with a melting point of 130 °C, an MFR (230 °C) of 9.5 g / 10 min, and a density of 0.91 g / cm 3 and 10% of low-density polyethylene with a melting point of 105 °C and an MFR (230 °C) of 12 g / 10 min by weight ratio. Innermost resin layer: A layer composed of a polypropylene random copolymer with a melting point of 145 °C and an MFR (230 °C) of 7.5 g / 10 min. The thickness ratio of the three layers of resin from the contact layer with the inner layer adhesive layer 7 to the innermost layer in the heat-sealing resin layer 8 is 1:8:1.

[0163] (6) Laminating method of solution-type inner layer adhesive B-3-b: The inner layer adhesive layer 7 uses a solution-type inner layer adhesive, and is composed of a maleic anhydride-modified polypropylene resin with a weight average molecular weight of 70,000, a melting point of 145 °C, and an acid value of 4.5 mg KOH / g, and amine compounds such as triethylamine and N,N-dimethylethanolamine as curing agents. It is uniformly applied to the corrosion-protected intermediate metal surface of the composite film in contact with the heat-sealing resin layer 8 to which the outer base material resin layer 1 is laminated, dried at a temperature of 160 °C for 2 min, and an adhesive layer B-3-b with a thickness of 4 μm is formed. At a temperature of 100 °C, an 80-μm melt-extruded three-layer heat-sealing resin thin film is pressure thermally bonded to the inner layer adhesive layer 7, and further heat-treated at a temperature of 180 °C for 5 s. In this way, a composite finished product of outer base material resin layer / outer layer adhesive layer (3 μm) / intermediate metal layer / inner layer adhesive layer (4 μm) / heat-sealing resin layer (80 μm) is formed.

[0164] The three-layer structure of the heat-sealing resin 8 is as follows: Resin layer in contact with the inner layer adhesive layer 7: It is a layer made of a polypropylene random copolymer with a melting point of 145 °C and an MFR (230 °C) of 7.5 g / 10 min. Intermediate resin layer: By weight ratio, it is a mixture layer formed from 35% polypropylene with a melting point of 162 °C and an MFR (230 °C) of 3 g / 10 min, 30% polypropylene with a melting point of 160 °C and an MFR (230 °C) of 5 g / 10 min, 15% crystalline polymer elastomer composed of ethylene-propylene with a melting point of 130 °C, an MFR (230 °C) of 9.5 g / 10 min, and a density of 0.91 g / cm 3 and 20% amorphous propylene-based elastomer with an MFR (230 °C) of 3 g / 10 min. Innermost resin layer: It is a layer made of a polypropylene random copolymer with a melting point of 145 °C and an MFR (230 °C) of 7.5 g / 10 min. The thickness ratio of the three-layer resin from the contact layer with the inner layer adhesive layer 7 to the innermost layer in the heat-sealing resin layer 8 is 1:8:1. Example 1

[0165] The metal foil used was an annealed 8079 series aluminum foil with a thickness of 30 μm and a surface wettability of 70 dyn / cm. Both sides of the aluminum foil were corrosion-proof treated. The components and contents of the corrosion-proof liquid capable of forming the corrosion-proof layer 6 on both sides of the aluminum foil are as shown in Table 1, which included a trivalent chromium compound, an inorganic acid, and an organic resin with 20 parts, 10 parts, and 10 parts by mass respectively. The trivalent chromium compound was chromium nitrate, the inorganic acids were phosphoric acid and nitric acid, and the organic resins were polyvinyl alcohol and polyacrylic resin. The chromium content in the corrosion-proof layer was 20 mg / m 2 is.

[0166] The outer base resin layer 1 used a non-simultaneous biaxially stretched nylon film with a thickness of 30 μm, and the inner layer adhesive layer 7 was laminated with the heat-sealing resin layer 8 in the B-2-a method. Example 2

[0167] The metal foil used was an annealed 8021 series aluminum foil with a thickness of 40 μm and a water contact angle of 10°. Both sides of the aluminum foil were corrosion-proof treated. The components and contents of the corrosion-proof liquid capable of forming the corrosion-proof layer 6 on both sides of the aluminum foil are as shown in Table 1, which included a trivalent chromium compound, an inorganic acid, and an organic resin with 20 parts, 20 parts, and 60 parts by mass respectively. The trivalent chromium compound was chromium nitrate, the inorganic acids were phosphoric acid and nitric acid, and the organic resins were polyvinyl alcohol and polyacrylic resin. The chromium content in the corrosion-proof layer was 10 mg / m 2 is.

[0168] The outer base resin layer 1 used a non-simultaneous biaxially stretched polyethylene terephthalate film (PET) with a thickness of 25 μm, and the inner layer adhesive layer 7 was laminated with the heat-sealing resin layer 8 in the B-1-a method. Example 3

[0169] The metal foil used was an annealed 8021 series aluminum foil with a thickness of 35 μm and a water contact angle of 15°. Both sides of the aluminum foil were corrosion-treated, and the components and contents of the corrosion protection liquid capable of forming the corrosion protection layer 6 on both sides of the aluminum foil were as shown in Table 1, which included a trivalent chromium compound, an inorganic acid, and an organic resin with 20 parts, 40 parts, and 40 parts by mass, respectively. The trivalent chromium compound was chromium phosphate, the inorganic acid was nitric acid, and the organic resin was a polyacrylic resin. The chromium content in the corrosion protection layer was 30 mg / m 2 is.

[0170] The outer base resin layer 1 used a non-simultaneous biaxially stretched nylon film with a total thickness of 15 μm, and the inner layer adhesive layer 7 was laminated with the heat-sealing resin layer 8 in the B-3-a method. Example 4

[0171] The metal foil used was an annealed nickel-plated iron foil with a thickness of 50 μm and a surface wettability of 68 dyn / cm. A nickel layer with a thickness of 1 μm was plated on the surface of the iron foil, and both sides of the iron foil were corrosion-treated. The components and contents of the corrosion protection liquid capable of forming the corrosion protection layer 6 on both sides of the iron foil were as shown in Table 1, which included a trivalent chromium compound, an inorganic acid, and an organic resin with 50 parts, 20 parts, and 20 parts by mass, respectively. The trivalent chromium compound was chromium nitrate, the inorganic acid was phosphoric acid, and the organic resin was a polyacrylic resin. The chromium content in the corrosion protection layer was 15 mg / m 2 is.

[0172] The outer base resin layer 1 used a non-simultaneous biaxially stretched polybutylene terephthalate film (PBT) with a thickness of 25 μm, and the inner layer adhesive layer 7 was laminated with the heat-sealing resin layer 8 in the B-1-b method. Example 5

[0173] The used metal foil is a heat-treated austenitic stainless steel foil with a thickness of 30 μm and a water contact angle of 10°. Both sides of the stainless steel foil are corrosion-proof treated. The components and contents of the corrosion-proof liquid capable of forming the corrosion-proof layer 6 on both sides of the stainless steel foil are as shown in Table 1, which contains a trivalent chromium compound, an inorganic acid, and an organic resin with 60 parts, 12 parts, and 36 parts by mass respectively. The trivalent chromium compound is chromium nitrate, the inorganic acid is phosphoric acid and nitric acid, and the organic resin is polyvinyl alcohol and polyacrylic resin. The chromium content in the corrosion-proof layer is 25 mg / m 2 is.

[0174] The outer base resin layer 1 uses a co-extruded film of a non-simultaneously biaxially stretched polyethylene terephthalate film (12 μm) with a total thickness of 27 μm, a polyurethane-based adhesive (2 μm), and a non-simultaneously biaxially stretched nylon film (15 μm). The inner layer adhesive layer 7 is laminated with the heat-sealing resin layer 8 in the B-2-b method. Example 6

[0175] The used metal foil is an annealed 8021 series aluminum foil with a thickness of 80 μm and a water contact angle of 5°. Both sides of the aluminum foil are corrosion-proof treated. The components and contents of the corrosion-proof liquid capable of forming the corrosion-proof layer 6 on both sides of the aluminum foil are as shown in Table 1, which contains a trivalent chromium compound, an inorganic acid, and an organic resin with 36 parts, 6 parts, and 6 parts by mass respectively. The trivalent chromium compound is chromium nitrate, the inorganic acid is phosphoric acid and nitric acid, and the organic resin is polyvinyl alcohol and polyacrylic resin. The chromium content in the corrosion-proof layer is 35 mg / m 2 is.

[0176] The outer base resin layer 1 uses a non-simultaneously biaxially stretched polyethylene terephthalate film (PET) with a thickness of 25 μm. The inner layer adhesive layer 7 is laminated with the heat-sealing resin layer 8 in the B-3-b method. Example 7

[0177] The metal foil used was an annealed 8021 series aluminum foil with a thickness of 40 μm and a surface wettability of 72 dyn / cm. Both sides of the aluminum foil were corrosion-treated, and the components and contents of the corrosion inhibitor solution capable of forming the corrosion protection layer 6 on both sides of the aluminum foil were as shown in Table 1, which included a trivalent chromium compound, an inorganic acid, a fluoride, and an organic resin with 20 parts, 20 parts, 10 parts, and 60 parts by mass, respectively. The trivalent chromium compound was chromium nitrate, the fluoride was chromium fluoride, the inorganic acid was phosphoric acid and nitric acid, and the organic resin was polyvinyl alcohol and polyacrylic resin. The chromium content in the corrosion protection layer was 20 mg / m 2 is.

[0178] The outer base resin layer 1 used a composite film of a non-simultaneously biaxially stretched polyethylene terephthalate film (12 μm) with a total thickness of 27 μm, a polyurethane-based adhesive (2 μm), and a non-simultaneously biaxially stretched nylon film (15 μm). The nylon side of the composite film was in contact with the outer layer adhesive layer 2, and the inner layer adhesive layer 7 was laminated with the heat-sealing resin layer 8 in the B-1-a method.

[0179] Compared with Examples 1, 2, and 4, in this example, since a certain amount of fluoride was increased in the corrosion inhibitor solution capable of forming the intermediate metal corrosion protection layer 6, it was found that when the metal composite film finished product was placed in an electrolyte environment with and without water for 3 days, the peel strength between its aluminum foil and the heat-sealing resin layer 8 was relatively high. It is shown that by introducing fluoride, the corrosion resistance of the metal surface corrosion protection film can be further improved on top of Examples 1, 2, and 4. Comparative Example 1

[0180] The metal foil used was an annealed 8021 series aluminum foil with a thickness of 40 μm and a water contact angle of 10°. Both sides of the aluminum foil were corrosion-treated, and the components and contents of the corrosion inhibitor solution capable of forming the corrosion protection layer 6 on both sides of the aluminum foil were as shown in Table 1, which included a trivalent chromium compound, an inorganic acid, a fluoride, and an organic resin with 30 parts, 4 parts, 4 parts, and 6 parts by mass, respectively. The trivalent chromium compound was chromium phosphate, the inorganic acid was phosphoric acid, and the organic resin was aminophenol resin. The chromium content in the corrosion protection layer was 15 mg / m2 It is.

[0181] The outer substrate resin layer 1 uses a composite film of an unstretched biaxially oriented polyethylene terephthalate film (12 μm) with a total thickness of 27 μm, a polyurethane-based adhesive (2 μm), and an unstretched biaxially oriented nylon film (15 μm). The nylon side of the composite film is in contact with the outer layer adhesive layer 2, and the inner layer adhesive layer 7 is laminated with the heat-sealing resin layer 8 in the B-1-a method.

[0182] Compared with Examples 1 to 7, when the corrosion inhibitor solution capable of forming the intermediate metal corrosion protection layer 6 contains a certain proportion of trivalent chromium compound, inorganic acid, fluoride, and organic resin component, it was found that the retention rates of the peel strength after being placed in the electrolyte environment without water and with water for 3 days reached 82 - 95% and 71 - 80% respectively. In Comparative Example 1, a commonly used corrosion inhibitor solution in the market was applied, and the initial peel strength of the metal composite film finished product was only 11.1 N / 15 mm. The retention rates of the peel strength after being placed in the electrolyte environment without water and with water for 3 days were 80.5% and 61.3% respectively, which was found to be significantly different from the corrosion resistance of the corrosion-protected metal composite film of the present disclosure. It is clear that the corrosion-protected metal of the present disclosure can improve the adhesion between the metal of the metal composite film and the inner heat-sealing resin and the corrosion resistance in the electrolyte environment without water and with water to a certain extent. Comparative Example 2

[0183] The metal foil used is an annealed 8021 series aluminum foil with a thickness of 40 μm and a surface wettability of 70 dyn / cm. Both sides of the aluminum foil are corrosion-protected, and the components and contents of the corrosion inhibitor solution capable of forming the corrosion protection layer 6 on both sides of the aluminum foil are as shown in Table 1, which contains a trivalent chromium compound, an inorganic acid, and an organic resin with 66 parts, 6 parts, and 6 parts by mass respectively. The trivalent chromium compound is chromium nitrate, the inorganic acids are phosphoric acid and nitric acid, and the organic resins are polyvinyl alcohol and polyacrylic resin. The chromium content in the corrosion protection layer is 20 mg / m 2 It is.

[0184] The outer substrate resin layer 1 uses a non-simultaneous biaxially stretched nylon film with a thickness of 30 μm, and the inner layer adhesive layer 7 is combined with the heat-sealing resin layer 8 in the B-2-a method.

[0185] Compared with Examples 1 to 6, in this comparative example, although the same trivalent chromium compound, inorganic acid, and organic resin components were included, the content of the trivalent chromium compound was relatively high, the initial peel strength of the metal composite film finished product decreased slightly, and it was found that the retention rate of the peel strength after being placed in an electrolyte environment without water for 3 days decreased to 75.2%, and the retention rate of the peel strength after being placed in an electrolyte environment with water for 3 days decreased to 50.2%. It is clear that improving the corrosion resistance of the metal composite film if the ratio of the substance components for the corrosion protection treatment of the metal surface according to the examples of the present disclosure is within the scope of the claims of the present disclosure. Comparative Example 3

[0186] The used metal foil is an annealed 8021 series aluminum foil with a thickness of 40 μm and a water contact angle of 10°. Both sides of the aluminum foil are corrosion-protected, and the components and contents of the corrosion protection liquid capable of forming the corrosion protection layer 6 on both sides of the aluminum foil are as shown in Table 1, which includes a trivalent chromium compound, an inorganic acid, and an organic resin with 20 parts, 20 parts, and 80 parts by mass respectively. The trivalent chromium compound is chromium nitrate, the inorganic acid is phosphoric acid and nitric acid, and the organic resin is polyvinyl alcohol and polyacrylic resin. The chromium content in the corrosion protection layer is 20 mg / m 2 is.

[0187] The outer substrate resin layer 1 uses a non-simultaneous biaxially stretched nylon film with a thickness of 30 μm. Corona treatment is required on the surface of the composite film joined to the dark side of the aluminum foil, and the inner layer adhesive layer 7 is combined with the heat-sealing resin layer 8 in the B-2-a method.

[0188] Compared with Examples 1 to 7 and Comparative Example 2, in this comparative example, although the same trivalent chromium compound, inorganic acid, and organic resin component were included, the content of the organic resin was relatively high, exceeding the scope of the claims of the present disclosure. The initial peel strength of the metal composite film finished product was only 10.3 N / 15 mm, and the retention rate of the peel strength decreased to 62.9% after being placed in an electrolyte environment without water for 3 days, and the retention rate of the peel strength decreased to 31.5% after being placed in an electrolyte environment with water for 3 days. It was discovered that the ratio of the substance components of the anticorrosive treatment on the metal surface has a very significant impact on the corrosion resistance of the metal composite film. If the ratio of the substance components of the anticorrosive treatment on the metal surface according to the embodiment of the present disclosure is within the scope of the claims of the present disclosure, the corrosion resistance of the metal composite film can be effectively improved.

[0189] Table 1 Components and contents of the anticorrosive liquid capable of forming an anticorrosive layer on the intermediate metal layer of the metal composite film, and statistical results of the evaluation of corrosion resistance JPEG0007706564000001.jpg165170Remarks: The retention rate refers to the ratio of the peel strength between the metal / / inner weld layer measured after exposure to the electrolyte to the initial strength.

[0190] The above description is merely some examples of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made in accordance with the spirit and principle of the present disclosure should all be included in the claims of the present disclosure. The technical scope of this disclosure is not limited to the content in the specification, and the technical scope must be determined by the scope of the patent claims.

Claims

1. A method for manufacturing a metal composite film including an outer base resin layer, an intermediate metal layer, and a heat-sealing resin layer, wherein a corrosion prevention layer is formed on a side of the intermediate metal layer that contacts the heat-sealing resin layer, the corrosion prevention layer is formed by applying or heat-treating a corrosion prevention liquid, mass percentages of a trivalent chromium compound, an inorganic acid, and an organic resin in the corrosion prevention liquid are 1.9 to 6%, 0.3 to 6%, and 0.6 to 6% respectively, the trivalent chromium compound consists of one of chromium nitrate, chromium phosphate, and chromium chloride, the organic resin consists of a polyacrylic acid-based resin, or a polyacrylic acid-based resin and polyvinyl alcohol, the corrosion prevention liquid further contains a fluoride selected from chromium fluoride and aluminum fluoride, and a mass ratio of the trivalent chromium compound, the inorganic acid, the organic resin, and the fluoride in the corrosion prevention liquid is (19 to 60):(3 to 60):(6 to 60):(1 to 10). A method for manufacturing a metal composite film, characterized by the above.

2. The mass ratio of the trivalent chromium compound, the inorganic acid, the organic resin, and the fluoride in the corrosion prevention liquid is 20:20:60:

10. A method for manufacturing a metal composite film according to Claim 1, characterized by the above.

3. The metal composite film further includes an inner layer adhesive layer provided between the corrosion prevention layer and the heat-sealing resin layer. A method for manufacturing a metal composite film according to Claim 1 or 2, characterized by the above.

4. The metal composite film further includes an outer layer adhesive layer provided between the outer base resin layer and the intermediate metal layer. A method for manufacturing a metal composite film according to Claim 3, characterized by the above.

5. The metal composite film further includes an outer layer adhesive layer provided between the outer base resin layer and the intermediate metal layer. A method for manufacturing a metal composite film according to Claim 1 or 2, characterized by the above.

6. The metal composite film further includes a coloring layer, and the coloring layer is provided between the outer base resin layer and the outer layer adhesive layer, or the coloring layer is formed by adding a pigment to the outer layer adhesive layer. A method for manufacturing a metal composite film according to Claim 4 or 5, characterized by the above.

7. The metal composite film further includes a coloring layer provided outside the outer base resin layer. A method for manufacturing a metal composite film according to any one of Claims 1 to 5, characterized by the above.

8. An outer anticorrosion layer is provided on the side of the intermediate metal layer that contacts the outer adhesive layer or the outer base resin layer. The method for manufacturing a metal composite film according to any one of claims 1 to 7, characterized in that.

9. The inorganic acid consists of one or more of nitric acid and phosphoric acid. The method for manufacturing a metal composite film according to any one of claims 1 to 8, characterized in that.

10. The polyacrylic acid-based resin is one or more of polyacrylic acid, polymethyl acrylate, a copolymer of acrylic acid and maleic acid, a copolymer of acrylic acid and styrene, and its sodium salt and ammonium salt derivatives, and the weight average molecular weight of the polyacrylic acid-based resin is 10,000 to 800,000. The method for manufacturing a metal composite film according to claim 1, characterized in that.

11. The thickness of the anticorrosion layer is 1 nm to 3.0 μm. The method for manufacturing a metal composite film according to any one of claims 1 to 8, characterized in that.

12. The thickness of the anticorrosion layer is 1 nm to 1.5 μm. The method for manufacturing a metal composite film according to claim 11, characterized in that.

13. The chromium content in the anticorrosion layer is between 8 and 50 mg / m ２ 2. The method for manufacturing a metal composite film according to any one of claims 1 to 8, characterized in that.

14. The chromium content in the anticorrosion layer is between 10 and 30 mg / m ２ therebetween, The method for manufacturing a metal composite film according to claim 13, characterized in that.

15. The anticorrosion layer is formed by applying and heat-treating an anticorrosion liquid. The method for manufacturing a metal composite film according to any one of claims 1 to 8, characterized in that.

16. The coating methods include bar coating method, roll coating method, gravure coating method and dipping method. The method for manufacturing a metal composite film according to claim 15, characterized in that.

17. A solution-type adhesive is used for the inner adhesive layer, the components of the solution-type adhesive include an acid-modified polyolefin resin and a curing agent, and the thickness of the inner adhesive layer is 1 to 10 μm. The method for manufacturing a metal composite film according to claim 3, characterized in that.

18. The melting point of the acid-modified polyolefin resin is between 60 and 155 °C, the weight average molecular weight is in the range of 10,000 to 150,000, and the acid value is in the range of 0.5 to 200 mg KOH / g. The method for manufacturing a metal composite film according to claim 17, characterized in that.

19. The curing agent is one or more selected from isocyanate, epoxy resin or oxazoline, or one or more selected from triethylamine and N,N-dimethylethanolamine, and the acid modifier used for the acid-modified polyolefin resin is one of maleic anhydride, methacrylic acid, acrylic acid and itaconic anhydride. The method for manufacturing a metal composite film according to claim 17, characterized in that.

20. When the curing agent is one or more selected from triethylamine and N,N-dimethylethanolamine, the mass ratio of the acid-modified polyolefin resin to the curing agent is 10:1 to 125:

1. The method for manufacturing a metal composite film according to claim 19, characterized in that.

21. The mass ratio of the acid-modified polyolefin resin to the curing agent is 15:1 to 50:

1. The method for manufacturing a metal composite film according to claim 20, characterized in that.

22. The acid-modified polyolefin resin is one or a mixture of a polypropylene block copolymer resin, a polypropylene random copolymer resin and a homopolypropylene resin in which the content of polypropylene having a melting point of 110 °C or higher exceeds 50%. The method for manufacturing a metal composite film according to claim 18, characterized in that.

23. A hot-melt type inner adhesive is used for the inner adhesive layer, the component of the hot-melt type inner adhesive contains an acid-modified polyolefin resin, and the thickness of the inner adhesive layer is 2 to 80 μm. The method for manufacturing a metal composite film according to claim 3, characterized in that.

24. The melting point of the acid-modified polyolefin resin is between 135 and 165 °C, and the MFR (230 °C) is between 3 and 15 g / 10 min. The method for manufacturing a metal composite film according to claim 23, characterized in that.

25. The acid modifier used for the acid-modified polyolefin resin is one of maleic anhydride, methacrylic acid, acrylic acid and itaconic anhydride, and the degree of modification of the polyolefin resin is 1 to 15%. The method for manufacturing a metal composite film according to claim 23, characterized in that.

26. The heat-sealing resin layer is a mixed resin of one or two or more selected from an acid-modified polyolefin resin, a homopolypropylene resin, a polypropylene block copolymer resin, a polypropylene random copolymer resin and a polyethylene resin. The method for manufacturing a metal composite film according to claim 1 or 2, characterized in that...

27. The melting point of the constituent resin of the heat-sealing resin layer is between 120 and 162 °C, the MFR (230 °C) is 2 to 15 g / 10 min, and the thickness of the heat-sealing resin layer is 20 to 120 μm. The method for manufacturing a metal composite film according to claim 26, characterized in that...

28. Use of the metal composite film produced by the method for manufacturing a metal composite film according to any one of claims 1 to 27 in an electrochemical device.

Images