CN115101862B

CN115101862B - A corrosion-resistant metal-plastic composite film

Info

Publication number: CN115101862B
Application number: CN202210654899.3A
Authority: CN
Inventors: 庄志; 王卉; 刘倩倩; 程跃
Original assignee: Jiangsu Ruijie New Material Technology Co ltd
Current assignee: Jiangsu Ruijie New Material Technology Co ltd
Priority date: 2022-06-10
Filing date: 2022-06-10
Publication date: 2024-12-10
Anticipated expiration: 2042-06-10
Also published as: CN115101862A

Abstract

The present invention provides a corrosion-resistant metal-plastic composite film, in which an anti-corrosion layer is formed on at least one side of a metal layer, and the content of each element in the anti-corrosion layer is in a gradient distribution. The content of each element in the anti-corrosion layer is controlled to improve the initial peeling strength and corrosion resistance between the metal layer and the first resin layer of the metal-plastic composite film, and the moisture intruding into the anti-corrosion layer can react with the anti-corrosion layer to generate hydrogen fluoride, so that the anti-corrosion layer is further inhibited from being dissolved, and a bridging agent can be added to the anti-corrosion layer to improve the crosslinking density of the anti-corrosion layer, so that the tolerance of the anti-corrosion layer to an electrolyte as a content and hydrogen fluoride generated by the reaction of the electrolyte and water is stabilized.

Description

Corrosion-resistant metal-plastic composite film

Technical Field

The invention relates to the technical field of metal plastic film production, in particular to a corrosion-resistant metal plastic composite film.

Background

At present, lithium ion batteries are mainly divided into three major categories of square, cylindrical and soft package, wherein the shells of the square and cylindrical mainly adopt hard shells such as aluminum alloy, stainless steel and the like, the aluminum alloy shell can be aluminum, and the soft package shell formed by laminating metal and resin adopts a metal-plastic composite film, so that the problem of inflexible appearance design of the hard-packaged battery is greatly solved.

The metal-plastic composite film is used as a battery outer coating material, and needs to have electrolyte corrosion resistance, so that the problems of leakage and the like of a battery shell can be prevented, the service life of a battery is ensured, in general, metals in the metal-plastic composite film for lithium ion battery outer coating need to be subjected to corrosion prevention treatment, if moisture is mixed in a battery manufacturing process under the condition of unsatisfactory corrosion prevention treatment effect, the metals react with lithium salt in electrolyte to generate corrosive Hydrogen Fluoride (HF), and the hydrogen fluoride can reach the surface of the metal layer through a heat welding resin layer and an adhesive layer thereof, so that the metals are corroded, and the metal and the heat welding resin layer are separated from each other, therefore, the possibility of leakage of electrolyte from the battery is increased, and the corrosion prevention treatment of the metal layer has great influence on the metal-plastic composite film.

The main components of the corrosion-resistant liquid of the metal-plastic composite film at present are trivalent chromium compounds, fluorides, amino phenol resin and phosphoric acid, after the metal layer is subjected to corrosion-resistant treatment by the corrosion-resistant liquid, the corrosion resistance degree of the metal-plastic composite film can be improved in some common electrolyte environments, but in long-term use of the battery, moisture can penetrate through the battery outer package, so that the electrolyte generates hydrogen fluoride, at the moment, the corrosion-resistant treatment effect of the corrosion-resistant liquid is not ideal, interlayer separation of the metal-plastic composite film for the lithium ion battery is easily caused, and popularization and use of the metal-plastic composite film in the field of lithium ion batteries are affected.

Disclosure of Invention

The invention aims to provide a corrosion-resistant metal-plastic composite film, which comprises an anti-corrosion layer containing carbon element, metal element and fluorine element, wherein the distribution of various elements is in gradient distribution along with the direction from one side far away from the metal layer to the side close to the metal layer, so that high corrosion resistance can be realized, and the possibility of leakage of electrolyte from a battery is greatly reduced.

Another object of the present invention is to provide a corrosion-resistant metal-plastic composite film in which a bridging agent is added to an anticorrosive layer to increase the crosslinking density of the anticorrosive layer and stabilize the anticorrosive layer against hydrogen fluoride generated by an electrolyte solution as a content and a reaction of the electrolyte solution with water.

In order to achieve the above object, the present invention provides a metal-plastic composite film having corrosion resistance, comprising:

A metal layer

The corrosion-resistant layer is arranged on at least one side of the metal layer, the corrosion-resistant layer comprises a carbon element, a metal element and a fluorine element, and the carbon element, the metal element and the fluorine element are distributed in a gradient manner from one side of the corrosion-resistant layer far away from the metal layer to the side close to the metal layer.

Preferably, the anticorrosive layer includes a first anticorrosive region, a second anticorrosive region and a third anticorrosive region, the first anticorrosive region is the side of the anticorrosive layer away from the metal layer, the second anticorrosive region is located between the first anticorrosive region and the third anticorrosive region, and the third anticorrosive region is the side of the anticorrosive layer close to the metal layer, wherein in the first anticorrosive region, the content ratio of the carbon element is 40% -100%, and the content ratio of the metal element is not more than 5%, in the second anticorrosive region, the content ratio of the metal element is 10% -70%, and in the third anticorrosive region, the content ratio of the metal element is 20% -100%.

Preferably, in the second anticorrosive region, the content ratio of the fluorine element is not more than 30%, and the ratio value of the fluorine element to the metal element is not more than 2, and in the third anticorrosive region, the content ratio of the fluorine element is not more than 20%, and the ratio value of the fluorine element to the metal element is not more than 1.

Preferably, the material of the metal layer is at least one of aluminum alloy, stainless steel, titanium steel or nickel plating.

Preferably, the anti-corrosion layer is formed by an anti-corrosion liquid, the anti-corrosion liquid is formed by mixing a trivalent chromium compound, an inorganic acid and an organic resin with water or an organic solvent, the trivalent chromium compound accounts for 1.9-6% of the anti-corrosion liquid, the inorganic acid accounts for 0.3-6% of the anti-corrosion liquid, the organic resin accounts for 0.6-6% of the anti-corrosion liquid, and the water or the organic solvent accounts for 78.6-97.2% of the anti-corrosion liquid.

Preferably, the trivalent chromium compound is at least one of chromium nitrate or chromium fluoride.

Preferably, the inorganic acid is at least one of phosphoric acid, nitric acid or hydrofluoric acid.

Preferably, the organic resin is at least one of an acrylic resin, a methacrylic resin, a hydroxyacrylic resin, a polyvinyl alcohol resin, an olefin resin, and a phenolic resin.

Preferably, the organic solvent is at least one of isopropanol, ethanol and ethylene glycol butyl ether.

Preferably, the component of the anticorrosive layer comprises a bridging agent, wherein the bridging agent is at least one of amino resin, melamine resin, phenolic resin, epoxy compound, blocked isocyanate compound, oxazoline compound, carbodiimide compound, condensate of formaldehyde and monohydric alcohol with 1-4 carbon atoms, and condensate of carbolic acid or formaldehyde.

Preferably, the proportion of the bridging agent in the solid component of the anti-corrosion liquid is 0.05% -15%, or the proportion of the bridging agent in the solid component of the anti-corrosion layer is 0.01% -30%.

Preferably, the anticorrosive layer comprises a titanium (Ti) compound and a zirconium (Zr) compound, the content ratio of the titanium (Ti) compound is not more than 0.6%, and the content ratio of the zirconium (Zr) compound is not more than 2.8%.

Preferably, the titanium (Ti) compound is at least one of titanium fluoride or titanium nitrate, and the zirconium (Zr) compound is at least one of zirconium fluoride and zirconium nitrate.

Preferably, the resin composition further comprises a first resin layer and a second resin layer, wherein the first resin layer is arranged on one side of the metal layer, and the second resin layer is arranged on the other side of the metal layer.

Preferably, the first resin layer is adhered to the metal layer by a first adhesive.

Preferably, the material of the first adhesive is at least one of block polypropylene resin (B-PP), random copolymer polypropylene resin (R-PP) or homo-polypropylene resin (H-PP), and the content of polypropylene (PP) in the block polypropylene resin (B-PP), random copolymer polypropylene resin (R-PP) and homo-polypropylene resin (H-PP) is not less than 50%.

Preferably, the second resin layer is adhered to the metal layer by a second adhesive.

Preferably, the first resin layer is a heat-welded resin layer, wherein the material of the first resin layer is at least one of polyolefin, cyclic polyolefin or modified polyolefin-based resin.

Preferably, the modified polyolefin-based resin is at least one of a carboxylic acid-modified polyolefin, a carboxylic acid-modified cyclic polyolefin, a methacrylic acid-modified polyolefin, an acrylic acid-modified polyolefin, a crotonic acid-modified polyolefin, and an imide-modified polyolefin.

Preferably, the side of the metal layer to which the first resin layer is bonded forms the corrosion prevention layer.

In order to achieve the above another object, the present invention provides a method for forming a metal-plastic composite film with corrosion resistance, comprising the steps of:

A metal layer

The corrosion-resistant layer is arranged on at least one side of the metal layer, the corrosion-resistant layer comprises a carbon element, a metal element, a fluorine element and a bridging agent, and the carbon element, the metal element and the fluorine element are distributed in a gradient manner from one side of the corrosion-resistant layer away from the metal layer to the side close to the metal layer.

Preferably, the material of the metal layer is at least one of aluminum alloy, stainless steel, titanium steel or nickel-plated steel plate.

Preferably, the trivalent chromium compound is at least one of chromium nitrate or chromium fluoride, the inorganic acid is at least one of phosphoric acid, nitric acid or hydrofluoric acid, the organic resin is at least one of acrylic resin, methacrylic resin, hydroxy acrylic resin, polyvinyl alcohol resin, olefin resin or phenolic resin, and the organic solvent is at least one of isopropanol, ethanol and ethylene glycol butyl ether.

Preferably, the bridging agent is at least one of amino resin, melamine resin, phenolic resin, epoxy compound, blocked isocyanate compound, oxazoline compound, carbodiimide compound, condensate of formaldehyde and C1-4 alkyl monoalcohol, condensate of carbolic acid and formaldehyde, and derivatives thereof.

Preferably, the bridging agent comprises at least one of a silicon compound, a zirconium compound, a metal chelate or an inorganic bridge of a metal salt.

Preferably, the silicon compound is silicon dioxide.

Preferably, the zirconium compound is at least one of zirconium ammonium fluoride or zirconium ammonium carbonate.

Preferably, the metal chelate is a titanium chelate.

Preferably, the metal salt is at least one of calcium (Ca), aluminum (Al), magnesium (Mg), iron (Fe), and zinc (Zn).

Preferably, the titanium (Ti) compound is at least one of titanium fluoride or titanium nitrate, and the zirconium (Zr) compound is at least one of zirconium fluoride or zirconium nitrate.

Preferably, the first resin layer is a heat-welding resin layer, wherein the material of the first resin layer is at least one of polyolefin, cyclic polyolefin or modified polyolefin.

Preferably, the modified polyolefin is at least one of a aliphatic carboxylic acid modified polyolefin, a carboxylic acid modified cyclic polyolefin, a methacrylic acid modified polyolefin, an acrylic acid modified polyolefin, a crotonic acid modified polyolefin, or an imide modified polyolefin.

The invention has the beneficial effects that the anti-corrosion layer with gradient distribution of each element is formed on the metal layer, the initial peeling strength and corrosion resistance between the metal layer and the first resin layer of the metal-plastic composite film can be improved, and the moisture which invades the anti-corrosion layer can react with the anti-corrosion layer to generate hydrogen fluoride.

Drawings

FIG. 1 is a schematic view of a metal-plastic composite film according to a first embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a metal-plastic composite film according to a second embodiment of the present invention, and

FIG. 3 is a flow chart of a method according to an embodiment of the invention.

Detailed Description

In order to make the above and/or other objects, effects and features of the present invention more comprehensible, preferred embodiments accompanied with figures are described in detail below:

Referring to fig. 1-2, schematic structural diagrams of metal plastic composite films according to a first embodiment to a second embodiment of the present invention are shown. As shown in the drawings, the structural difference is that the corrosion-resistant metal-plastic composite film 1 of the present invention includes a metal layer 11 and an anti-corrosion layer 12, and further, the metal-plastic composite film 1 further includes a first resin layer 13 and a second resin layer 14, wherein the anti-corrosion layer 12 is disposed on at least one side of the metal layer, the first resin layer 13 is disposed on one side of the metal layer 11, and the second resin layer 14 is disposed on the other side of the metal layer 11, and the detailed description is as follows:

The material of the metal layer 11 is at least one of aluminum alloy, stainless steel, titanium steel, and nickel plating, and in one embodiment, the metal layer 11 may be of a sheet metal type or a foil type, but is not limited thereto, wherein when an aluminum alloy foil is used, a soft aluminum alloy foil composed of an annealed aluminum alloy or the like is more preferable, and from the viewpoint of further improving formability, or an aluminum alloy foil containing an iron component is preferable, silica, magnesium, or the like may be added depending on the need of an electrolyte resistance or the like, and when a stainless steel foil is used, an austenitic, ferritic, austenitic, martensitic, precipitation-hardening stainless steel foil may be used, and more preferably an austenitic stainless steel such as SUS304, SUS301, or SUS316L, and preferably SUS304 is preferable.

In one embodiment, when the metal layer 11 is in the form of a metal foil, the thickness thereof is 9 μm to 200 μm, more preferably, the thickness of the metal layer 11 is 9 μm to 100 μm, still more preferably, the thickness of the metal layer 11 is 9 μm to 50 μm, but the thickness thereof is not limited thereto as long as it can function as the metal layer 11 for inhibiting the penetration of moisture.

In another embodiment, when the metal layer 11 is in the form of a metal plate, it is preferable to form a nickel plating layer on one side of the metal layer 11, so that the metal layer 11 further increases the corrosion resistance such as rust resistance, and also improves the surface cleanliness of the metal layer 11, wherein the thickness of the nickel plating layer is not more than 10 μm, and more preferably, the thickness of the metal layer 11 is 1 μm to 5 μm, so as to avoid cracking easily under an external pressure load when the thickness is too high, but not limited thereto.

For this reason, conventionally, when the metal layer 11 has an alloy component, the alloy component is deposited on the surface of the metal layer 11, or when the annealing process is performed in the rolling process, the volatility of the rolling oil is affected, and therefore, in the adjustment of the alloy component, the surface cleanliness of the metal layer 11 becomes important, and the surface cleanliness can be managed by a method using a wettability test reagent as an index, or a method using a contact angle as an index, wherein the wettability index is class a to class D, preferably class B, and the contact angle index is measured with pure water, and the contact angle is not more than 25 °, preferably not more than 20 °, more preferably not more than 15 °, and in one embodiment, the metal layer 11 surface wettability test method can be used as "the state standard of the people's republic GB/T225638.5-2016", the metal test method, the part 5 of the metal layer 11 contact angle test method can be used as "the state standard of the people's republic GB/T22638.9-2008", and the metal test method part 9 of the hydrophilicity "is not limited thereto.

When the wettability is lower than D or the contact angle exceeds 25 °, the reactivity of the anti-corrosion layer 12 or the initial adhesion will be deteriorated, and if the reactivity is deteriorated, the reaction between the anti-corrosion layer 12 and the metal layer 11 will become insufficient, the permeation resistance against the electrolyte solution as a battery and the hydrogen fluoride resistance due to the reaction between the electrolyte and water will be reduced, so that the adhesion of the anti-corrosion layer 12 to the metal layer 11 will be significantly reduced with the lapse of time, the dissolution of the anti-corrosion layer 12 will occur, the peeling phenomenon will occur between the metal layer 11 and the anti-corrosion layer 12, and the life of the battery will be shortened, and in addition, the same will occur when the initial adhesion between the anti-corrosion layer 12 and the metal layer 11 is deteriorated.

The anticorrosive layer 12 includes carbon element, metal element and fluorine element, and the distribution of each element from the side of the anticorrosive layer 12 away from the metal layer 11 to the side near the metal layer 11 shows gradient distribution, in one embodiment, the anticorrosive layer includes a first anticorrosive region, a second anticorrosive region and a third anticorrosive region, the first anticorrosive region is the side of the anticorrosive layer away from the metal layer, the second anticorrosive region is located between the first anticorrosive region and the third anticorrosive region, and the third anticorrosive region is the side near the metal layer, and therefore, in the first anticorrosive region, the content ratio of carbon element is 40% -100% and the content ratio of metal element is not more than 5%, in the second anticorrosive region, the content ratio of metal element is 10% -70% and the content ratio of fluorine element is not more than 30%, and the ratio value of fluorine element to metal element is not more than 2, and in the third anticorrosive region, the content ratio of metal element is not more than 20%, and the ratio of fluorine element to metal element is not more than 1, but not limited thereto.

In one embodiment, after the corrosion protection layer 12 is soaked in an electrolyte containing 1000PPM of water for 5 days, the corrosion protection layer 12 is controlled to have a fluorine content of not more than 30% and a fluorine content of not more than 2% in the second corrosion protection area, and to have a fluorine content of not more than 20% and a fluorine content of not more than 1 in the third corrosion protection area, and in one embodiment, the electrolyte contains a mixed solvent of EC, DEC and DMC of 1mol/L LiPF6, wherein the mass ratio EC: DEC: DMC is 1:1:1, and soaked for 5 days, but not limited thereto.

The gradient distribution function of each element in the anticorrosive layer 12 is as follows:

In the first corrosion prevention area, when the content ratio of the carbon element is less than 40% or the content of the metal element is greater than 5%, the adhesion strength between the corrosion prevention layer 12 and the first adhesive 131 is unstable and is affected by the electrolyte, and at the same time, the peeling strength is reduced during the preservation process, or the internal insulation is reduced due to the increase of the content of the metal element, so that the service life of the battery is reduced, or the electrolyte leaks due to the electrical short circuit between the external packing material and the inside of the battery;

When the content ratio of fluorine element in the second anticorrosive region is more than 30%, the adhesive strength of the first adhesive 131 tends to be unstable due to the relative decrease in resin composition by the oblique distribution in the anticorrosive layer 12, and when the ratio of fluorine element to metal element is more than 2, the hydrogen fluoride corrosive effect by the electrolytic solution tends to be reduced, and the peel strength of the first adhesive 131 to the metal layer 11 may be greatly reduced over a long period of time, and

When the ratio of fluorine element in the third anticorrosive region is more than 20%, the reaction product of the anticorrosive layer 12 and the metal layer 11 becomes small, and the peel strength of the first adhesive 131 and the metal layer 11 may be greatly reduced for a long period of time, and when the ratio of fluorine element to metal element in the third anticorrosive region is more than 1, the hydrogen fluoride corrosion effect by the electrolyte may be reduced, and the peel strength of the first adhesive 131 and the metal layer 11 may be greatly reduced for a long period of time, and at the same time, the carbon element content of the first adhesive 131 increases the carbon component of the first resin layer 13 in contact with the anticorrosive layer 12 in the first anticorrosive region, so that the adhesion stability of the first adhesive 131 between the first resin layer 13 and the metal layer 11 may be ensured, whereas when the adhesion of the first adhesive 131 is unstable, the adhesion strength may be reduced and the peel strength may be unstable when the electrolyte permeates.

In summary, the first corrosion prevention region has a tilt structure in which the metal element is gradually increased as it approaches the metal layer 11 side, so that the penetration of the electrolyte or the reaction of the electrolyte with water can be suppressed even if the electrolyte is contacted with the electrolyte while maintaining the adhesion with the first resin layer 13, and the tilt structure is a crosslinked structure in order to suppress the penetration of the hydrogen fluoride into the electrolyte.

In an embodiment, when the aluminum component in the anti-corrosion layer 12 increases, the adhesion between the anti-corrosion layer 12 and the metal layer 12 increases, so that when the flexible package lithium battery is used for a long period of time, the water intruded into the flexible package lithium battery reacts with the electrolyte to generate hydrogen fluoride, at this time, dissolution of the anti-corrosion layer 12 on the metal layer 11 is inhibited, the peeling strength stability between the first adhesive 131 and the metal layer 11 is further ensured, and the effect increases with the increase of the fluoride component in the anti-corrosion layer 12.

In one embodiment, the anti-corrosion layer 12 is formed by mixing an anti-corrosion solution with trivalent chromium compound, inorganic acid and organic resin, wherein the trivalent chromium compound accounts for 1.9-6% of the anti-corrosion solution, the inorganic acid accounts for 0.3-6% of the anti-corrosion solution, the organic resin accounts for 0.6-6% of the anti-corrosion solution, the water or organic solvent accounts for 78.6-97.2% of the anti-corrosion solution, and the organic solvent serves to reduce the surface tension of the anti-corrosion solution to increase the leveling property of the anti-corrosion solution on the surface of the metal layer 11.

In one embodiment, the trivalent chromium compound is at least one of chromium nitrate or chromium fluoride, and forms a coordination cross-linking structure with chromium (Cr) atoms as the center on the surface of the metal layer 11, at this time, the trivalent chromium compound plays a role of increasing the cross-linking degree of the corrosion-resistant film on the surface of the metal layer 11, the inorganic acid is at least one of phosphoric acid, nitric acid or hydrofluoric acid, the organic resin is at least one of acrylic resin, methacrylic resin, hydroxyacrylic resin, polyvinyl alcohol resin, olefin resin or phenolic resin, and the organic solvent is at least one of isopropanol, ethanol and ethylene glycol butyl ether, but is not limited thereto.

In one embodiment, the anti-corrosion solution further comprises a titanium (Ti) compound or a zirconium (Zr) compound, and the titanium (Ti) compound or the zirconium (Zr) compound is used as a secondary center crosslinking point to play a role of enhancing the corrosion resistance of the surface of the metal layer 11, wherein the proportion of the titanium (Ti) compound in the anti-corrosion solution is not more than 0.6%, the proportion of the zirconium (Zr) compound in the anti-corrosion solution is not more than 2.8%, and the titanium (Ti) compound is at least one of titanium fluoride and titanium nitrate, and the zirconium (Zr) compound is at least one of zirconium fluoride and zirconium nitrate, but not limited thereto.

In addition, it is presumed that the effective component in the anticorrosive liquid reacts with the metal layer 11 to generate reaction products, for example, reaction products of the resin component in the anticorrosive layer 12 with chromium (Cr), titanium (Ti), zirconium (Zr), reaction products of the inorganic acid with chromium (Cr), and reaction products of the fluoride or the inorganic acid in the metal layer 11 and the anticorrosive layer 12.

In one embodiment, the anti-corrosion liquid further comprises a bridging agent, which can increase the crosslinking density of the anti-corrosion layer 12 by adding the bridging agent, so that the corrosion-resistant layer 12 is more stable to hydrogen fluoride generated by the reaction of the electrolyte with water, wherein the bridging agent is divided into an organic bridging agent and an inorganic bridging agent, the inorganic bridging agent comprises at least one of silica and other silica compounds, zirconium compounds such as zirconium ammonium fluoride and zirconium ammonium carbonate, titanium chelate and other metal chelates, ca, al, mg, fe, zn and other metal salts, but not limited thereto, and the organic bridging agent comprises at least one of amino resin, melamine resin, phenolic resin, epoxy compound, blocked isocyanate compound, oxazoline compound, carbodiimide compound, condensate of formaldehyde and monohydric alcohol with 1-4 carbon atoms, condensate of stone carbonic acid and formaldehyde, but not limited thereto.

In one embodiment, the bridging agent is at least one of a compound having any one of an isocyanate chemical group, a glycidyl chemical group, a carboxyl chemical group, an oxazoline chemical group, and a silane coupling agent, but is not limited thereto.

In one embodiment, the proportion of the bridging agent in the solid component of the anti-corrosion liquid is 0.05% -15%, or the proportion of the bridging agent in the solid component of the anti-corrosion layer 12 is 0.01% -30%, but not limited thereto, wherein when the proportion of the bridging agent in the anti-corrosion liquid is less than 0.05%, the corrosion resistance of the anti-corrosion layer 12 cannot be improved by adding the bridging agent, whereas when the proportion of the bridging agent in the anti-corrosion liquid exceeds 15%, the crosslinking density of the anti-corrosion layer 12 becomes high, resulting in the anti-corrosion layer 12 being too hard, and thus cracking or peeling of the anti-corrosion layer 12 is relatively easy to occur in the molding process, thereby reducing the corrosion resistance thereof.

In addition, the corrosion-preventing layer 12 may be formed of various conventional corrosion-preventing liquids including phosphates, nitric acid, chromates, fluorides, rare earth oxides, etc., wherein when phosphates or chromates are used, for example, chromium chromate treatment, chromium phosphate treatment, phosphoric acid-chromate treatment, etc. are required, and chromium compounds used for treatment, for example, chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium biphosphate, chromium acetate, chromium chloride, or chromium sulfate, and, in the chromate treatment, etching chromate treatment, electrolytic chromate treatment, coating type chromate treatment, etc., are mainly used, preferably, coating type chromate treatment.

The application type chromate treatment further includes degreasing treatment in which a treatment liquid containing at least one of a metal phosphate or a nonmetal phosphate such as a chromium (Cr) phosphate, a titanium (Ti) phosphate, a zirconium (Zr) phosphate, a lead (Zn) phosphate, etc. as a main component is mixed with a synthetic resin, and then the mixture is applied and dried by a known application method such as a roll coating method, a gravure printing method, or a dipping method, and various solvents such as water, an alcohol solvent, a hydrocarbon solvent, a ketone solvent, an ester compound solvent, or an ether solvent may be used as the treatment liquid, and water is preferable.

In one embodiment, the anti-corrosion layer 12 may be a film obtained by a coating type anti-corrosion treatment, wherein the coating type anti-corrosion treatment may be selected from at least one component including an oxide sol of a rare earth element, an anionic polymer, or a cationic polymer, but is not limited thereto.

When a cationic polymer is used, it includes at least one component selected from polyethylene pipe imine, a complex ion polymer complex formed from a polymer having polyethylene pipe imine and carboxylic acid, a primary amine glatiramer tolya resin in which a primary amine is graft-copolymerized on an acrylic main chain, polyacetic acid or a derivative thereof, and an aminated phenol, but is not limited thereto.

When an anionic polymer is used, it includes at least one component of a copolymer comprising poly (meth) acrylic acid or a salt thereof, or (meth) acrylic acid or a salt thereof as a main component, but is not limited thereto.

In one embodiment, the coating agent may include at least one combination of phosphoric acid, phosphate, or bridging agent, and when rare earth oxide sol is used, fine particles of rare earth oxide, for example, particles having an average particle diameter of 100nm or less, are dispersed in a liquid dispersion medium, and the liquid dispersion medium is, for example, water, an alcohol-based solvent, a hydrocarbon-based solvent, a ketone-based solvent, an ester-based solvent, or an ether-based solvent, and preferably water, and when rare earth oxide is used, it includes at least one combination of cerium oxide, yttrium oxide, neodymium oxide, or lanthanum oxide, and preferably cerium oxide, and the rare earth oxide contained in the corrosion preventing layer 12 may be used alone or in combination.

In an embodiment, the anti-corrosion liquid is coated on at least one side of the surface of the metal layer 11 to form the anti-corrosion layer 12, but not limited thereto, more preferably, the anti-corrosion layer 12 may be formed on both sides of the surface of the metal layer 11, and the anti-corrosion layer 12 functions to prevent hydrogen fluoride generated by the reaction of the electrolyte and the moisture from corroding the surface of the metal layer 11, and at the same time, maintain uniformity of the surface of the metal layer 11 so that the adhesiveness, i.e., wettability, is less, and for this reason, the anti-corrosion layer 12 may allow the metal layer 11 to be stored in a high temperature and high humidity environment for a long period of time, and for this reason, the thickness of the anti-corrosion layer 12 is not particularly limited, and in an embodiment, the thickness of the anti-corrosion layer 12 is 1nm to 3.0 μm, and preferably, but not limited thereto, the thickness is 1nm to 1.5 μm.

Further, the metal plastic composite film 1 of the present invention further includes a first resin layer 13 and a second resin layer 14, wherein the first resin layer 13 is disposed on one side of the metal layer 11, the second resin layer 14 is disposed on the other side of the metal layer 11, and in an embodiment, the first resin layer 13 is adhered to one side of the metal layer 11 by a first adhesive 131, but not limited thereto, or the first adhesive 131 may not be used, and the second resin layer 14 may be adhered to the other side of the metal layer 11 by a second adhesive 141, or the second adhesive 141 may not be used, wherein the first resin layer 13 is mainly heat-sealable, and the material of the first resin layer 13 is at least one of polyolefin, cyclic polyolefin or acid-modified polyolefin, but not limited thereto.

The polyolefin material may be at least one of a low density polyethylene, a medium density polyethylene, a high density polyethylene, a polyethylene ethylene- α -olefin copolymer such as a linear low density polyethylene, a homopolypropylene, a polypropylene block copolymer (e.g., a block copolymer of propylene and ethylene), a random copolymer of polypropylene (e.g., a random copolymer of propylene and ethylene), and the like, a propylene- α -olefin copolymer, or a terpolymer of ethylene-butene-propylene, and among these, polypropylene is preferable, and when a copolymer is used, the polyolefin may be a block copolymer or a random copolymer, and these polyolefin materials may be used singly or in combination.

The acid-modified polyolefin may be at least one of aliphatic carboxylic acid-modified polyolefin, carboxylic acid-modified cyclic polyolefin, methacrylic acid-modified polyolefin, acrylic acid-modified polyolefin, crotonic acid-modified polyolefin, and imide-modified polyolefin, and the acid-modified polyolefin is a polymer modified by block polymerization or graft polymerization of an acid component with polyolefin, and for this purpose, the acid-modified polyolefin may be formed by copolymerizing a polar molecule such as polyacrylic acid or methacrylic acid with polyolefin, and in addition, the acid component used in the acid modification may be carboxylic acid such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, itaconic anhydride, sulfonic acid, or anhydride, and preferably acrylic acid, maleic acid, or anhydride, but is not limited thereto.

In one embodiment, the first resin layer 13 further contains a slipping agent, which has the effect of improving the formability of the outer package material for lithium ion batteries, wherein the total type of slipping agent is not particularly limited, and may be selected from known ranges, and the slipping agent may be used singly or in combination, preferably, an amide-based slipping agent is selected, but is not limited thereto.

In the case where the slipping agent is present on the surface of the first resin layer 13, the content is not particularly limited, and from the viewpoint of improving the moldability of the electronic packaging material, the slipping agent content may be preferably 10mg/m ²-50mg/m², more preferably 15mg/m ² to 40mg/m2, and the slipping agent may be oozed out of the resin of the heat-fusible resin layer or may be coated on the surface of the first resin layer 13.

In one embodiment, the first resin layer 13 further includes an antioxidant, which can suppress thermal degradation in the manufacturing process, wherein the kind of the antioxidant is not particularly limited, and may be selected from known ranges, and the antioxidant is used singly or in combination.

In one embodiment, when the first resin layer 13 is used to assemble a battery, the heat-fusible resin layer is used to seal the battery module by heat fusion, and the first resin layer 13 may be made of a single or a plurality of resins, and further, may be made of the same or different resins.

In one embodiment, the thickness of the first resin layer 13 is required to satisfy the function of sealing the battery assembly after the heat welding of the first resin layer 13, and therefore, the thickness thereof is in the range of 20 μm to 120 μm, preferably in the range of 25 μm to 80 μm, if the thickness of the first resin layer 13 is less than 20 μm, it will not sufficiently cover the deviation of the mechanical processing dimensions and conditions of the heat sealing device or the like, it will be difficult to obtain a uniform heat welding portion, resulting in unstable sealability, whereas if the thickness of the first resin layer 13 exceeds 120 μm, the water vapor permeation amount will increase, resulting in the increase of moisture inside the battery, resulting in the generation of gas by reaction with the electrolyte, so that the risk of swelling, cracking or leakage of the electrolyte will occur, and the battery life will be reduced accordingly.

Meanwhile, the first resin layer 13 has a melting point in the range of 120 ℃ to 162 ℃, and preferably has a melting point in the range of 130 ℃ to 162 ℃, for example, a single layer or a composite layer composed of at least one mixture having an MFR (230 ℃) of 2 to 15g/10 minutes, more preferably an MFR (230 ℃) of 3 to 12g/10 minutes, but is not limited thereto.

In one embodiment, when the first resin layer 13 is a composite layer, the contact surface with the metal layer 11 is not formed, the thickness of the side is not less than 2 μm, and the melting point is in the range of 130 ℃ to 152 ℃, so that the fluidity of the resin is improved by heating when the melting point is 120 ℃ or less, and the thickness thereof is reduced by heat sealing under pressure, the adhesion to the metal layer 11 is reduced, and at the same time, the extruded portion of the resin from the inside of the battery flows to the edge not being extruded by pressure, at this time, the crack is caused by the external force of the expansion and shrinkage and bending process of the battery, so that the electrolyte permeates into the metal layer 11 through the crack, the insulation resistance of the first resin layer 13 is reduced, and thus the leakage phenomenon occurs, and the life of the battery is shortened.

On the other hand, when the melting point exceeds 162 ℃, the crystallinity of the resin is improved, so that the resin fluidity is relatively low at the time of pressure heat sealing, and the heat resistance is improved to form a hard and brittle resin layer, and therefore the expansion and shrinkage of the battery and the external force of bending work will cause cracks, and the stable sealability will not be obtained, and similarly, when the MFR (230 ℃) is lower than 2g/10 minutes or when the MFR (230 ℃) of the resin exceeds 15g/10 minutes, the same problem will be caused. In addition, the resin in the extruded portion of the battery flows to the edge portion which is not extruded by the pressing, and the crack is caused by the expansion and contraction of the battery, the external force of bending processing and the like, the electrolyte permeates to the middle metal layer through the crack, the insulation resistance of the heat welding resin layer is reduced, the electric leakage phenomenon occurs, and the service life of the battery is shortened.

The first adhesive 131 mainly functions to adhere the metal layer 11 and the first resin layer 13, and for this purpose, the thickness of the first adhesive 131 is in the range of 1 μm to 80 μm, and preferably in the range of 1 μm to 50 μm, and in one embodiment, the material of the first adhesive 131 is a resin, and the resin may or may not contain a polyolefin main chain, preferably a polyolefin main chain, and the polyolefin used for the first adhesive 131 and its modified resin are the same as the resin used for the first resin layer 13, and are polypropylene resin, propylene or ethylene copolymer, but not limited thereto.

In an embodiment, the first adhesive 131 may be a resin composition containing an acid-modified polyolefin and a curing agent, and when an acid-modified polyolefin is used, it is preferably maleic anhydride or an acrylic-modified polyolefin, and the curing agent used is not particularly limited, and may be at least one curing agent selected from epoxy-based curing agents, polyfunctional isocyanate-based curing agents, carbodiimide-based curing agents and oxazoline-based curing agents, but is not limited thereto.

When an epoxy-based curing agent is used as the curing agent, it is sufficient to use a compound having at least one epoxy group, for example, at least one combination of bisphenol a diglycidyl ether, modified bisphenol a diglycidyl ether, novolak diglycidyl ether, polyglycidyl ether or polyglycidyl ether, when a polyfunctional isocyanate-based curing agent is used as the curing agent, it is sufficient to use only a compound having at least two isocyanate groups, for example, isophorone diisocyanate (PDI), hexamethylene Diisocyanate (HDI), toluene Diisocyanate (TDI), a polymerized or added component of diphenylmethane diisocyanate (MDI) or a mixture of these and other polymer, when a carbodiimide-based curing agent is used as the curing agent, it is sufficient to use only a compound having at least one carbodiimide group (-n=c=n-), for example, a polycarbodiimide compound having at least two carbodiimide groups, and when an oxazoline-based curing agent is used, it is sufficient to use only a compound having an oxazoline skeleton, and of course, it is also sufficient to use two or more compounds.

In an embodiment, the material of the first adhesive 131 is at least one of a modified polyolefin resin, a block copolymerized polypropylene resin (B-PP) with a polypropylene (PP) content of more than 50%, a random copolymerized polypropylene resin (R-PP) or a homo-polymerized polypropylene resin (H-PP), and the structure is single-layer or multi-layer, but not limited thereto.

When the first adhesive 131 is used to compound the metal layer 11 and the first resin layer 13, a method of using a solution type first adhesive 131 may be used, or a method of using a hot melt type first adhesive 131 may be used, wherein the solution type first adhesive 131 is mainly composed of an acid-modified polyolefin resin, and at least one kind of combination of isocyanate, epoxy resin or oxazoline is used as a hardener, or an amine compound such as triethylamine, N-dimethylethanolamine is used as a hardener, and after being dissolved in a solvent of at least one kind of combination of water, ethanol, isopropanol, ethyl acetate, methyl ethyl ketone, toluene or methylcyclohexane, the solution is uniformly applied to the surface of the metal layer 11, and the solvent is volatilized by heating, so that the thickness of the first adhesive 131 reaches a desired effect, preferably about 1 to 10 μm, more preferably about 1 to 5 μm.

When the thickness of the first adhesive 131 is less than 1 μm, the adhesion between the metal layer 11 and the first resin layer 13 is lowered, so that the adhesion becomes a problem, whereas when the thickness of the first adhesive 131 exceeds 10 μm, a hard resin layer is formed in the case of a curing agent reaction, and at this time, the bending resistance is deteriorated, so that the flexibility of the metal-plastic composite film 1 is lowered, and there is a risk of occurrence of cracks in bending.

The melting point of the acid-modified polyolefin resin in the solution type first adhesive 131 is 60-155 ℃, the weight average molecular weight is 10000-150000, the acid value of the solution type first adhesive 131 is 0.5-200mgKOH/g, the solution type first adhesive 131 mainly consists of acid-modified polyolefin and amine compound as hardener without curing agent, wherein the ratio of the acid-modified polyolefin to the amine compound is 10-125:1, preferably 15-50:1, the acid used for the modified polyolefin is maleic acid, fumaric acid, methacrylic acid, etc., the amine compound is at least one combination of triethylamine or N, N-2 methylethanolamine, the acid-modified polyolefin is polypropylene with the melting point of 110 ℃ or more, and the content of polypropylene is 50% or more.

When the melting point of the acid-modified polyolefin is 60 ℃ or less, the heat resistance thereof is low, and at this time, the metal layer 11 and the first resin layer 13 may be peeled off at a high temperature, and when the melting point of the acid-modified polyolefin exceeds 155 ℃, the heat resistance thereof is relatively good, but when it reacts with the curing agent, a hard resin layer is formed, and the flexibility of the metal-plastic composite film 1 is deteriorated, or cracks may be generated by bending, and the metal layer 11 and the first resin layer 13 may be peeled off.

When the weight average molecular weight of the acid-modified polyolefin resin is 10000 or less, the fluidity of the resin is high, and the thickness of the first adhesive 131 is severely reduced in the heat sealing, and the adhesion strength between the metal layer 11 and the first resin layer 13 becomes low in the case of the reaction of adding a curing agent, and there is a problem in sealability, whereas when the weight average molecular weight of the acid-modified polyolefin resin exceeds 150000, the metal layer 11 and the first resin layer 13 form a hard resin layer in the case of the reaction of adding a curing agent, and the flexibility of the metal-plastic composite film 1 is deteriorated, or cracks are generated by bending, and the metal layer 11 and the first resin layer 13 may be peeled.

When the acid value of the acid-modified polyolefin resin is less than 0.5mgKOH/g, the point of reaction with the curing agent is small, and at this time, the adhesion between the metal layer 11 and the first resin layer 13 is unstable, and when the acid value of the acid-modified polyolefin resin exceeds 200mgKOH/g, the curing reaction between the curing agent and the acid-modified polyolefin resin is too severe, a hard resin layer is formed, and the bending resistance is deteriorated, so that the flexibility of the metal-plastic composite film 1 is lowered, or cracks are generated by bending, and the metal layer 11 and the first resin layer 13 may be peeled off.

The heat-fusible first adhesive 131 uses an acid-modified polyolefin resin having a melting point of 135-165 ℃ and an MFR (230 ℃) of 3-15g/10 min, the thickness of the formed first adhesive 131 is 2-80 μm, preferably 5-50 μm, the degree of modification of the acid-modified polyolefin resin used for the heat-fusible first adhesive 131 is 1% -15%, preferably 3% -12%, and when the melting point of the acid-modified polyolefin resin is 135 ℃ or less, the resin fluidity becomes high by heating, the thickness becomes extremely thin by pressure heat sealing, the adhesion strength of the metal layer 11 to the first resin layer 13 becomes low, and there is a problem of sealability.

When the melting point of the acid-modified polyolefin resin is 165 ℃ or higher, fluidity is relatively low at the time of heat sealing under pressure, heat resistance is improved, but when compounded with the metal layer 11, the heat shrinkage is increased, so that the internal stress is increased, and the adhesion ability of the heat-melted first adhesive 131 to the metal layer 11 is lowered, and therefore, when left for a long period of time, peeling from the metal layer 11 is likely to occur, and further, when heated at the time of heat sealing, the adhesion strength with the metal layer 11 is lowered, and the sealing strength is lowered, and when the MFR (230 ℃) of the acid-modified polyolefin resin is lower than 3g/10 minutes, the extrusion film forming property is unstable at the time of compounding after heat melting with the metal layer 11, whereas when the MFR (230 ℃) of the acid-modified polyolefin resin is higher than 15g/10 minutes, the adhesion strength between the metal layer 11 and the first resin layer 13 is lowered, and the sealing property is problematic.

When the thickness of the heat-fusible first adhesive 131 is less than 2 μm, the heat shrinkage is not absorbed because the heat shrinkage amount is too large when the heat-fusible first adhesive 131 is compounded with the metal layer 11, and therefore, the adhesion force with the metal layer 11 is reduced due to an increase in internal stress, and therefore, when the heat-fusible first adhesive 131 is left for a long period of time, peeling from the metal layer 11 may occur, and when the thickness of the heat-fusible first adhesive 131 exceeds 80 μm, no physical problem occurs, but the production price increases, and when the modification degree of the heat-fusible first adhesive 131 is less than 1%, the adhesiveness with the metal layer 11 is unstable, and when the modification degree of the heat-fusible first adhesive 131 exceeds 15%, physical problem does not occur, but the production price increases.

The thickness of the second resin layer 14 is not particularly limited as long as it functions as a base material, and in one embodiment, the resin of the second resin layer 14 is, for example, at least one of polyester, polyamide, polyolefin, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, phenolic resin, or a modified product of these resins, and the resin forming the second resin layer 14 may be a copolymer of these resins, a modified product of these resins, or a mixture of these resins, preferably at least one of polyester or polyamide, preferably at least one of a stretched polyester film and a stretched polyamide film, preferably at least one of a stretched polyethylene terephthalate film, a stretched polybutylene terephthalate film, a stretched nylon film, or a stretched polypropylene film, preferably at least one of a biaxially stretched polyethylene terephthalate film, a biaxially stretched polybutylene terephthalate film, a biaxially stretched nylon film, or a stretched polypropylene film, and the second resin layer 14 may be a single layer or a multilayer, but not limited thereto.

When the second resin layer 14 is formed of a plurality of layers, the second resin layer 14 may be a composite film formed by the action of the second adhesive 141, or may be a resin composite film formed by coextrusion of resins, and may be a second resin layer 14 in an unstretched state, or may be a second resin layer 14 after being uniaxially or biaxially stretched, and when the second resin layer 14 is a resin composite film formed of a plurality of layers, the thickness of each of the resin films constituting the layers is preferably in the range of 2 μm to 30 μm, and when the thickness is less than 5 μm, the moldability and insulation are relatively poor, whereas when the thickness exceeds 35 μm, the flexibility is poor.

In an embodiment, the second resin layer 14 may be a single-layer or multi-layer composite film formed by at least one polymer material selected from a blown nylon, a synchronous or asynchronous biaxially oriented polyethylene terephthalate (PET), a synchronous or asynchronous biaxially oriented polybutylene terephthalate (PBT), a Polyimide (PI), and the like, and may be bonded to the metal layer 11 by at least one combination of coextrusion, coating, lamination and heat bonding, but is not limited thereto.

Among them, a multilayer resin composite film such as at least one of a composite film of a polyester film and a nylon film, a multilayer nylon composite film, a multilayer polyester composite film is preferable, and a stretched nylon film laminate, a multilayer stretched nylon composite film, a multilayer stretched polyester composite film is preferable, and when an outer base resin layer is used as a multilayer resin composite film, 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 is preferable, and a composite film of a polyethylene terephthalate film and a composite film of 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 is preferable, and further, since a polyester resin is hard to be discolored when an electrolyte is used to be adhered to a surface, when the second resin layer 14 is a multilayer resin composite film, a polyester resin film is preferable as an outermost layer of the second resin layer 14, and among them, a resin film of a multilayer adhesive may be used as the same adhesive as the second adhesive 141.

In an embodiment, the polyester used in the second resin layer 14 may be at least one of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene isophthalate, or a combination of copolyesters, wherein the copolyester may be a copolyester of which polyethylene terephthalate is the main body of the repeating unit, specifically, a copolymer polyester obtained by polymerizing polyethylene terephthalate as the main body of the repeating unit with ethylene isophthalate, that is, at least one of a copolyester (terephthalate/isophthalate)), a copolyester (terephthalate/adipate), a copolyester (terephthalate/sodium isophthalate), a copolyester (terephthalate/phenyl-dicarboxylate), a copolyester (terephthalate/decanedicarboxylate), and these polyesters may be used alone or in combination of a plurality of types, but are not limited thereto.

In one embodiment, the polyamide used in the second resin layer 14 may be at least one combination of aliphatic polyamides such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, and copolymers of nylon 6 and nylon 66, hexamethylenediamine-isophthalic acid-terephthalic acid copolyamides such as nylon 6I, nylon 6T, nylon 6IT, and nylon 6I6T (I represents isophthalic acid, T represents terephthalic acid), and aromatic polyamides such as polyamide MXD6 (polyamide PACM6 (poly bis (4-aminocyclohexyl) methane azide amide), which may be used alone or in various combinations.

In one embodiment, one or more of additives such as lubricant, flame retardant, anti-blocking agent, antioxidant, light stabilizer, tackifier, antistatic agent, etc. may be added to the surface and the inside of the second resin layer 14, for example, the surface of the second resin layer 14 is coated with a lubricant, preferably an amide-based lubricant, the coating content of the lubricant is not less than 3mg/m2, preferably the coating content is in the range of 4-30mg/m2, and the lubricant present on the surface of the second resin layer 14 may be a lubricant oozing out from the second resin layer 14 containing the lubricant, or the surface of the second resin layer 14 may be coated with a lubricant, wherein the amide-based lubricant includes at least one combination of saturated fatty acid amide, unsaturated fatty acid amide, substituted amide, methylol amide, saturated fatty acid bisamide, unsaturated fatty acid bisamide, fatty acid amide, and aromatic bisamide, but is not limited thereto.

In one embodiment, when a saturated fatty acid amide is used as the lubricant, it includes at least one combination of lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide, and when an unsaturated fatty acid amide is used as the lubricant, it includes oleic acid amide, erucic acid amide, and the like. The substituted amides include at least one combination of N-oil palmitoleic acid amide, N-stearamide, N-oil stearamide and N-stearamide, at least one combination of methylol stearic acid amide when methylol amide is used as the lubricant, methylene bis stearic acid amide, ethylene bis caprylic acid amide, ethylene bis lauric acid amide, ethylene bis stearic acid amide, ethylene bis hydroxy stearic acid amide, ethylene bis behenic acid amide and hexamethylene bis behenic acid amide, hexamethylene hydroxy stearic acid amide, N '-distearyl adipic acid amide, N' -distearyl sebacic acid amide and the like when saturated fatty acid bisamide is used as the lubricant. The unsaturated fatty acid bisamides include, but are not limited to, at least one combination of ethylene bis-oleamide, ethylene bis-erucamide, hexamethylene bis-oleamide, n ' -dioleyladipic acid amide and n, n ' -dioleylsebacic acid amide, at least one combination of stearamide ethyl stearate when the lubricant is a fatty acid ester amide, and at least one combination of m-xylylene bis-stearamide, m-xylylene bis-hydroxystearic acid amide, n ' -distearyl isophthalic acid amide when the lubricant is an aromatic bisamide.

There are various methods for producing the second resin layer 14, for example, a resin film directly formed from a resin, or a resin coating, wherein the resin film is an unextended film or an extended film, and the extended film is a one-axis extended film or a two-axis extended film, preferably a two-axis extended film, and as a method for producing a two-axis extended film, for example, a stepwise two-axis extended method, a blown film method, or a simultaneous stretching method, and a method for coating a resin, for example, a roll coating method, a dimple coating method, an extrusion coating method, or the like, but are not limited thereto.

The second adhesive 141 has an effect of improving the adhesion between the second resin layer 14 and the metal layer 11, and for this purpose, the thickness of the second adhesive 141 is in the range of 1 μm to 10 μm, preferably 2 μm to 5 μm, and the second adhesive 141 is, for example, a two-component curing type adhesive, or a one-component curing type adhesive, wherein the second adhesive 141 may be at least any one combination of a chemical reaction type, a solvent evaporation type, a thermal melting type, a thermal compression type, and the like, and the second adhesive 141 may be a single layer or a multiple layer, but is not limited thereto.

In one embodiment, the second adhesive 141 is a two-component polyurethane adhesive formed by using polyester polyol, polyurethane modified polyol, etc. as a diol main agent and aromatic or aliphatic isocyanate as a curing agent, wherein the curing agent may be selected according to the functional groups of the adhesive component, such as at least one of a multifunctional epoxy resin, a polymer containing methanesulfonic acid, a poislamine resin, and an inorganic acid, but not limited thereto.

In one embodiment, the second adhesive 141 further includes at least any combination of polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene isophthalate, and copolyester, polyether resins, polyurethane resins, epoxy resins, phenolic resins, nylon 6, nylon 66, nylon 12, polyamide resins such as copolyamide, polyolefin, cyclic polyolefin, acid-modified polyolefin, polyolefin-based resins such as acid-modified cyclic polyolefin, polyvinyl acetate, cellulose, (meth) acrylic resins, polyimide resins, polycarbonates, urea resins, amino resins such as melamine resins, neoprene, nitrile rubbers, rubbers such as styrene-butadiene rubbers, silicone resins, and the like, but is not limited thereto, and the preferred second adhesive 141 combination is any combination of binary or multicomponent polyesters, polyurethane-modified polyesters, or isocyanates, and the isocyanate is not particularly limited to a compound having a plurality of isocyanate groups in the molecule, for example, at least any one of isophorone diisocyanate (IPDI), toluene Diisocyanate (TDI), diphenylmethane-4, 4' -diisocyanate (MDI), and 1, 6-diisocyanate (HDI) and the like.

The second adhesive 141 may further contain at least one of a colorant, a thermoplastic elastomer, a thickener, and a filler, and the second adhesive 141 may contain at least one of a colorant, and may be used to color a packaging material for a lithium ion battery, and when at least one combination of a pigment and a dye is used as the colorant, for example, at least one of an azo-based pigment, a phthalocyanine-based pigment, a quinacridone-based pigment, an anthraquinone-based pigment, a dioxazine-based pigment, an indigo-based pigment, a perylene-based pigment, and an isoindoline-based pigment is used, and when an inorganic pigment is used, for example, at least one of a carbon black-based pigment, a titanium oxide-based pigment, a cadmium-based pigment, a lead-based pigment, and an isoindoline-based pigment may be used, and the average particle size of the pigment may be in the range of 0.05 μm to 5 μm, preferably in the range of 0.08 μm to 2 μm, and the packaging material for a lithium ion battery may be used to be colored, and the pigment content may be in the range of 5% to 60%, preferably 10% to 40%.

In an embodiment, a coloring layer 15 may be further disposed between the second resin layer 14 and the second adhesive 141, for example, the surface of the second resin layer 14, the surface of the second adhesive 141 or the surface of the metal layer 11 is coated with an ink containing a coloring agent, and the coloring agent used in the coloring layer 15 is the same as that described above, so that the description thereof is omitted.

Please refer to fig. 3, which is a flowchart illustrating a method for preparing a metal-plastic composite film according to an embodiment of the present invention. As shown in the figure, the method for forming the corrosion-resistant metal-plastic composite film comprises the following steps:

Step S1, mixing a trivalent chromium compound, inorganic acid and organic resin with water or an organic solvent to form an anti-corrosion liquid;

step S2, coating the anti-corrosion liquid on at least one side of the surface of a metal layer, generating an anti-corrosion layer on at least one side of the surface of the metal layer through heat treatment to form a metal-plastic composite film, wherein the anti-corrosion layer comprises a carbon element, a metal element and a fluorine element, and

And S3, setting a first resin layer on one side of the corrosion-resistant layer of the metal-plastic composite film.

In step S1, the trivalent chromium compound, the inorganic acid, the organic resin and the water or the organic solvent are mixed to form the anti-corrosion solution, and in one embodiment, a bridging agent may be further added, wherein examples of the trivalent chromium compound, the inorganic acid, the organic resin, the water or the organic solvent and the bridging agent are the same as those described above, and thus are not repeated herein.

As shown in step S2, an anticorrosive liquid is applied to at least one side of the surface of the metal layer 11, and an anticorrosive layer 12 is formed on at least one side of the surface of the metal layer 11 by heat treatment, so that the metal-plastic composite film 1 is formed, and the anticorrosive layer 12 contains carbon element, metal element and fluorine element, wherein the anticorrosive liquid is applied by a treatment method such as an alkali dipping method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, an oxygen activation method, a heat treatment (annealing treatment) during rolling, or the like.

Before the anti-corrosion liquid is applied, the metal layer 11 needs to be deoiled on the application side, the surface wettability of the metal layer 11 is preferably not less than 70dyn/cm, or the titration contact angle of distilled water is preferably not more than 15 degrees, and preferably not more than 10 degrees, if the wettability or the surface water contact angle of the metal layer 11 exceeds a given range, this indicates the possibility that the calendared oil still remains on the metal in the manufacturing stage, so that the interfacial adhesion capability formed between the anti-corrosion layer 12, the metal layer 11 and the first resin layer 13 becomes poor, and the battery is liable to fall off between the metal layer 11 and the first resin layer 13 under long-term placement, and battery leakage and the like are liable to occur, and as a precaution measure, it is possible to perform annealing treatment of not less than 150 ℃, and at the same time, deoiling of the plasma, corona method, alkali lye can be performed, wherein the method of deoiling is that the metal layer 11 is immersed in an alkali lye of 50 ℃ to 65 ℃ and treated with deionized water, and then washed 2 times with deionized water after a certain period of treatment, and then the deoiling treatment is performed, but the metal layer 11 is not limited to this.

When the metal layer 11 is deoiled, the anticorrosive liquid may be coated by bar coating, roll coating, gravure coating, dipping, etc., and the wet coating amount of the anticorrosive liquid on the metal layer 11 is in the range of 1.6 to 3.2g/m ², and after the anticorrosive liquid is coated, the metal layer is heat-treated at a high temperature of 130 to 200 ℃ for 0.5 to 5 minutes to form the anticorrosive layer 12, and in one embodiment, the metal oxides such as alumina, titania, ceria, tin oxide, etc. dispersed in phosphoric acid and the particulate matters of precipitated barium sulfate may be coated on the surface of the metal layer 11, and the sintering treatment is performed at not less than 150 ℃ to form the anticorrosive layer 12.

As shown in step S3, the first resin layer 13 is disposed on one side of the corrosion protection layer 12 of the metal-plastic composite film 1, and in one embodiment, the first resin layer 13 is bonded to one side of the corrosion protection layer 12 by the first adhesive 131, but the first adhesive 131 is not limited thereto, and the first resin layer 13 may be compounded to the metal layer 11 by heating and pressurizing, and then the film is formed by heating, ultraviolet treatment, electron beam treatment, or the like, so that a composite film composed of the first resin layer 13 and the metal layer 11 is obtained, wherein if the first adhesive 131 is compounded, the following four modes are broadly classified:

1. The dry lamination method comprises coating the metal layer 11 with the first adhesive 131 in solution, drying, thermally laminating with the adhesive surface of the first resin layer 13 at a predetermined temperature and pressure, and aging to form a metal layer 11/first adhesive 131/first resin layer 13 composite, preferably, corona treatment is performed in advance on the adhesive surface of the first resin layer 13 in contact with the first adhesive 131, and aging at a temperature of 60 ℃ below the melting point of the first adhesive 131 is also possible.

2. The melt extrusion method is that the heat-melted first adhesive 131 forms a heat-melted first adhesive 13 with a certain thickness on the metal layer 11 by means of resin melt extrusion, and the surface of the first adhesive 131 and the bonding surface of the first resin layer 13 are thermally compounded to form a composite of the metal layer 11/the first adhesive 131/the first resin layer 13, and in addition, in order to improve the peeling force between the metal layer 11 and the first resin layer 13, heat treatment at a temperature of not more than 60 ℃ of the melting point temperature of the first adhesive 131 can be performed.

3. Melt extrusion method the metal layer 11/first adhesive 131/first resin layer 13 composite is formed by the coextrusion method of the hot-melt first adhesive 131 and the first resin layer 13, and in order to improve the peeling force between the metal layer 11 and the first resin layer 13, a heat treatment at a temperature of not more than 60 ℃ may be performed.

4. The heat bonding method comprises coating the metal layer 11 with the aqueous solution type first adhesive 131, performing a drying process, and performing heat recombination with the bonding surface of the first resin layer 13 at a certain temperature and pressure to form a composite of the metal layer 11/the first adhesive 131/the first resin layer 13, and further, in order to enhance the peeling force between the metal layer 11 and the first resin layer 13, performing a heat treatment of not more than 60 ℃ of the melting point temperature of the first adhesive 131, wherein the first resin layer 13 may be formed by an extrusion method, or when a film is used, it is preferable that the bonding surface of the first resin layer 13 in contact with the first adhesive 131 is subjected to corona treatment in advance.

In one embodiment, the method further comprises:

and S4, setting a second resin layer on the other side of the metal-plastic composite film, wherein the side is opposite to the first resin layer.

As shown in step S4, the second resin layer 14 is disposed on the other side of the metal layer 11, and the side is opposite to the first resin layer 131, in an embodiment, the second adhesive 141 is applied between the metal layer 11 and the second resin layer 14 and heated at a certain temperature for a certain time, after the organic solvent volatilizes, the second resin layer 14 is further compounded with the metal layer 11 according to the second adhesive 141 at a certain temperature and under a certain pressure, and after the second resin layer 14 is stored at a certain temperature for a certain time, the second resin layer 14 is cured to obtain a composite film composed of the second resin layer 14/the second adhesive 141/the metal layer 11, and when the second adhesive 141 is not used for the compounding of the second resin layer 14 and the metal layer 11, the metal layer 11 and the second resin layer 14 are compounded by heating and pressurizing, and the second resin layer 14 is formed into a film by means of heating treatment, ultraviolet treatment or electron beam treatment, so on, so that the composite film composed of the second resin layer 14 and the metal layer 11 can be obtained, but not limited.

In one embodiment, the film of the second resin layer 14 in contact with the second adhesive 141 may be corona-treated, specifically, an amorphous polyester polyol having a weight average molecular weight of 5000 and tg of 50 ℃ and a hydroxyl value of 25mg KOH/g and an amorphous polyester polyol having a weight average molecular weight of 20000 and tg of-17 ℃ and a hydroxyl value of 8mg KOH/g are mixed in a weight ratio of 3:2, toluene Diisocyanate (TDI) is added to form an outer bonding liquid having an NCO/OH ratio of 6.2, and the second adhesive 141 on the metal layer 11 and the film of the second resin layer 14 are thermally compounded, and then curing treatment is performed at 80 ℃ for 3 days to form the second resin layer 14/second adhesive 141 (3 μm)/the metal layer 11, wherein the metal layer 11 may be subjected to corrosion-preventing treatment on both sides of the surface.

The peel strength between the metal layer 11 and the first resin layer 13 of the metal-plastic composite film 1 was tested as follows:

The initial peel strength test comprises the steps of preparing a metal plastic composite film 1 into a straight strip shape, wherein the sample bar size is 100mm x 15mm, using a tensile test device to conduct peel test between a metal layer 11 and a first resin layer 13, placing a peeled first resin layer 13 film in an upper clamping plate of a telescopic test device, placing the metal layer 11 in a lower clamping plate, conducting T-shaped peeling with 180 DEG peeling surface under the condition that the telescopic speed is 50 mm/min, and beginning to measure the peel strength between the metal layer 11 and the first resin layer 13, wherein the peeling strength is read in a mode that the moving distance between the metal layer 11 and the first resin layer 13 is 50mm, selecting an average value of the peel strength between 10mm and 40mm, and conducting parallel test in 5 pieces/group.

The metal-plastic composite film 1 was tested for anhydrous electrolyte resistance as follows:

The metal plastic composite film 1 sample is directly soaked in a mixed solvent containing 1mol/L of dimethyl carbonate (DMC) of LiPF6, diethyl carbonate (DEC) and Ethylene Carbonate (EC) in the mass ratio of 1:1:1, soaked for 3 days at the temperature of 85 ℃, taken out, washed with water for 15 minutes, and the surface moisture of the sample is wiped, and the peel strength between the metal layer 11 and the first resin layer 13 is measured according to the initial peel strength test method of a finished product.

The metal-plastic composite film 1 was tested for aqueous electrolyte resistance as follows:

Cutting the metal-plastic composite film 1 into strips with a width of 15mm and a length of 100mm, peeling the metal layer 11 from the first resin layer 13 for 20mm, immersing the strips in a solvent containing 1mol/L LiPF6 of dimethyl carbonate (DMC) diethyl carbonate (DEC) Ethylene Carbonate (EC) at a ratio of 1:1:1, adding 1000PPM water accounting for the total mass of the electrolyte, immersing the strips at a temperature of 85 ℃ for 3 days, taking out the strips, washing the strips with water for 15 minutes, keeping the water from wiping, and measuring the peeling strength between the intermediate metal layer 11 and the first resin layer 13 from the position of the pre-peeling in a state of residual part of water between the pre-peeling metal layer 11 and the first resin layer 13 according to a finished product initial peeling strength test method.

The measurement method is as follows:

1. water contact Angle measurement

The water contact angle measurement is carried out on the metal surface by using a German KRUSSDSA contact angle measuring instrument, the metal is flatly placed on an instrument workbench, the water yield of the injector is controlled to be 2 mu mL each time, the liquid adding speed is 2.67 mu mL/s, and the contact angle value of the water drop just dropped on the metal surface is recorded.

2. Determination of the dyne value

Using German Arcotest dyne pen to draw 2 lines with length of 10cm continuously on the metal surface, if the line shrinkage occurs within 3 seconds, the metal surface dyne value can not reach the dyne value of the dyne pen at the moment, and selecting the dyne pen with low dyne value for re-measurement.

3. Element 12 determination of corrosion protection layer

The element distribution of the anticorrosive layer 12 was measured by the ESCA method using XPS (AXIS supra, shimadzu). Ar ion sputtering sample metal surface, ion beam diameter of 800 μm, voltage of 15KV, ion beam sputtering depth of 5nm, sputtering rate of 3 nm/min, sputtering times of 7 times, signal source detection depth of 5nm, detection limit of 1 mill, and detection times of 8 times.

The method for preparing the liquid-resistant sample comprises cutting metal forming the anti-corrosion layer 12 into strips with the width of 20mm and the length of 100mm, immersing the strips in a solvent containing 1mol/L of LiPF6 of dimethyl carbonate (DMC) diethyl carbonate (DEC) Ethylene Carbonate (EC) in a ratio of 1:1:1, adding 1000PPM water accounting for the total mass of the electrolyte, immersing at 85 ℃ for 3 days, taking out, washing for 15 minutes, and wiping off the water.

Examples 1-2 and comparative example 1 were each uniformly coated on both sides of the surface of the metal layer 11 with an anticorrosive liquid by a coating roll, and then heat-baked at 190 ℃ for 2 minutes, with the anticorrosive layer 12 having a coating wet film amount of 5g/m2.

The final product is a semi-finished product, namely, the second resin layer 14/the second adhesive 141 (3 mu m)/the first adhesive 131 and the first resin layer 13 are compounded on the metal surface of the metal layer 11.

Compounding method of the molten first adhesive 131:

The first adhesive 131 was a dry maleic anhydride-modified polypropylene, and an adhesive layer having a thickness of 15 μm was formed on the metal layer 11 in contact with the first resin layer 13, and further, the first adhesive 131 was compounded with the first resin layer 13 having a thickness of 30 μm by melt coextrusion to the metal layer 11 in contact with the first resin layer 13, wherein the first adhesive 131 used was a dry maleic anhydride-modified random copolymer polypropylene 60% (by weight ratio) having a melting point of 140℃ C, MFR (230 ℃) of 5g/10 minutes, a modification degree of the dry maleic anhydride to the random copolymer polypropylene of 10%, a copolymer elastomer 24% (by weight ratio) of propylene and butene having a melting point of 160℃ C, MFR (230 ℃) of 2.6g/10 minutes and a density of 0.87g/cm3, and a copolymer elastomer of ethylene and propylene having a melting point of 130℃ C, MFR (230 ℃) of 9.5g/10 minutes and a density of 0.91g/cm3 (by weight ratio) of 5g/10 minutes, and a copolymer elastomer of ethylene and propylene having a density of 5.91 g/cm3 of 8% (by weight ratio of C, MFR ℃) of 8% (by weight ratio) of 5 g/10% were mixed.

The first resin layer 13 is composed of two layers, and has the following structure:

A first resin layer 13 in contact with the first adhesive 131, a mixture layer of 62% by weight of a random copolymer polypropylene having a melting point of 155℃and an MFR (230 ℃) of 4g/10 min, 33% of an amorphous propylene-based elastomer and 5% of a low-density polyethylene having a melting point of 110℃and an MFR (230 ℃) of 7.5g/10 min, and

The first resin layer 13 of the innermost layer was composed of a random copolymer polypropylene having a melting point of 155℃and an MFR (230 ℃) of 15g/10 min, wherein the thickness ratio of the first resin layer 13 in contact with the first adhesive 131 to the first resin layer 13 of the innermost layer was 8:2.

After the metal layer 11 was combined with the first adhesive 131 and the first resin layer 13, a heat treatment was performed at 180 ℃ for 2 seconds, and at this time, a composite film of the second resin layer 14/the second adhesive 141 (3 μm)/the metal layer 11/the first adhesive 131 (15 μm)/the first resin layer 13 (30 μm) was formed.

The other is to compound the first adhesive 131 and the first resin layer 13 on the metal surface of the semi-finished product, namely the second resin layer 14/the second adhesive 141 (3 μm)/the metal layer 11.

Solution type first adhesive 131 compounding method:

An anhydrous maleic anhydride-modified polypropylene solution having a weight average molecular weight of 80000 and a melting point of 80℃and an acid value of 2mg KOH/g and an aromatic isocyanate (HDI system, hexamethylene diisocyanate) solution were applied to the metal face 11 in a solid ratio of 20:1 to form a solution-type mixture, which was dried to form a bonding layer having a thickness of 4 μm, and then thermally compounded with the bonding face of the first resin layer 13 having a thickness of 25 μm at a temperature of 80℃and cured at a temperature of 60℃for 7 days to form a composite film of the second resin layer 14/the second adhesive 141 (3 μm)/the metal layer 11/the first adhesive 131 (25 μm), and the bonding face of the first resin layer 13 in contact with the first adhesive 131 was subjected to corona treatment in advance.

The first resin layer 13 is composed of three layers, and has the following structure:

The first resin layer 13 in contact with the first adhesive 131 is composed of a random copolymer polypropylene having a melting point of 145 ℃ and an MFR (230 ℃) of 7.5g/10 min;

An intermediate first resin layer 13 composed of a mixture of 40% by weight of a block polypropylene having a melting point of 162℃and an MFR (230 ℃) of 2g/10 min, 40% by weight of a block polypropylene having a melting point of 160℃and an MFR (230 ℃) of 5g/10 min, and 20% by weight of a crystalline polymer elastomer composed of ethylene-propylene having a melting point of 130℃and an MFR (230 ℃) of 9.5g/10 min and a density of 0.91g/cm3, and

The first resin layer 13 of the innermost layer was composed of a random copolymer polypropylene having a melting point of 145℃and an MFR (230 ℃) of 7.5g/10 min, wherein the thickness ratio of the first resin layer 13 from the contact with the first adhesive 131 to the innermost layer was 1:8:1.

Example 1

The metal layer 11 is aluminum foil, the thickness of the metal layer 11 is 40 μm, the metal layer 11 is 8021 series annealed metal with dyne value of 75dyn/cm, both sides of the surface of the metal layer 11 are subjected to corrosion prevention treatment, the proportion of each element in the corrosion prevention layer 12 on both sides of the surface of the metal layer 11 is as shown in table 1, the content ratio of chromium fluoride, hydrofluoric acid, polyvinyl alcohol resin and titanium fluoride on the surface of the obtained metal layer 11 is 15:1:3:2, the chromium (Cr) content of the surface coating of the metal layer 11 is 15mg/m ², wherein the first adhesive 131 is compounded with the first resin layer 13 by adopting a melting type first adhesive 131 compounding method.

Example 2

The metal layer 11 is made of aluminum foil, the thickness of the metal layer 11 is 40 μm, the metal is annealed by 8021 system with a water contact angle of 10 DEG, both sides of the surface of the metal layer 11 are subjected to corrosion prevention treatment, the proportion of each element in the corrosion prevention layer 12 on both sides of the surface of the metal layer 11 is as shown in the table 1, the content ratio of chromium phosphate to chromium fluoride, phosphoric acid and phenolic resin on the surface of the obtained metal layer 11 is 5:2:1, the chromium (Cr) content is coated on the surface of the metal layer 11 and is 12mg/m ², wherein the first adhesive 131 is compounded with the first resin layer 13 by adopting a fusion type first adhesive 131 compounding method.

Comparative example 1

The thickness of the metal layer 11 used was 40 μm, the metal was annealed at a water contact angle of 15 ° in 8021 system, both sides of the surface of the metal layer 11 were subjected to corrosion protection treatment, the contents of the elements in the corrosion protection layer 12 on both sides of the surface of the metal layer 11 were 2:1:5 as described in table 1, the content ratio of chromium fluoride, hydrofluoric acid, polyvinyl alcohol resin in the metal layer 11 was obtained, and the chromium (Cr) content was 5mg/m ² as coated on the surface of the metal layer 11, wherein the first adhesive 131 was compounded with the first resin layer 13 by the melt type first adhesive 131 compounding method.

In examples 1-2, the initial peel strength of the metal-plastic composite film was 10.0N/15mm or more, and the peel strength maintenance rates after 5 days in the anhydrous and aqueous electrolyte environments were 88.0% and 70.0%, respectively.

In the first anticorrosive region, the carbon content was 67%, the metal element content was 2.0%, the second anticorrosive region, i.e., 20nm from the anticorrosive layer 12 to the metal layer 11 side, the metal element content was 8%, and in the third anticorrosive region, i.e., 40nm from the anticorrosive layer 12 to the metal layer 11 side, the metal element content was 15%, and after 5 days of immersion in the electrolyte, the fluorine element to metal element ratio was as high as 3.0 at 20nm, the fluorine element content was as high as 32%, and the fluorine element to metal element ratio was as high as 1.5 at 40nm, and the fluorine element content was as high as 25%.

At this time, the initial strength was 9.5N/15mm, and the maintenance rate in the electrolyte resistance test was 65% in the absence of water and 24% in the presence of water, which showed lower values than in examples.

Table 1 statistics of various data of metal-plastic composite films

Remark that the maintenance rate means the ratio of the peel strength between the metal layer 11 and the first resin layer 13 to the initial strength after the electrolyte resistance

In summary, compared with the prior art, the positive effects of the present invention are that the elements in the anti-corrosion layer 12 on the surface of the metal layer 11 are distributed in a gradient, and the initial peel strength between the metal layer 11 and the first resin layer 13 of the metal-plastic composite film 1, i.e. the corrosion resistance in the electrolyte environment with more water addition, can be improved by controlling the carbon element and metal element content in the first anti-corrosion region, the fluorine element and metal element content in the second anti-corrosion region and the third anti-corrosion region in the anti-corrosion layer 12, and as can be seen from the table, the peel strength test of examples 1-2 is many times higher than that of comparative example 1, and the maintenance rate is quite good.

The foregoing is merely a preferred embodiment of the present invention, and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the concept of the present invention, and are intended to be comprehended within the scope of the present invention.

Claims

1. A corrosion resistant metal plastic composite film comprising:

A metal layer

The corrosion protection layer is arranged on at least one side of the metal layer, the corrosion protection layer comprises a carbon element, a metal element and a fluorine element, the carbon element, the metal element and the fluorine element are distributed in a gradient manner from one side of the corrosion protection layer away from the metal layer to the side close to the metal layer, the corrosion protection layer comprises a first corrosion protection area, a second corrosion protection area and a third corrosion protection area, the first corrosion protection area is the side of the corrosion protection layer away from the metal layer, the second corrosion protection area is positioned between the first corrosion protection area and the third corrosion protection area, the third corrosion protection area is the side of the corrosion protection layer close to the metal layer, wherein the content proportion of the carbon element is 50% in the first corrosion protection area, the content proportion of the metal element is 2%, the content proportion of the metal element is 45%, the content proportion of the fluorine element is 10%, the fluorine element is 0.2% in the chromium fluoride value, the content proportion of the fluorine element is 5 mg/2% in the chromium fluoride resin, the content of the fluorine element is 5 mg/2 mg/m, the fluorine element is 2 mg/chromium fluoride resin, the fluorine element is 5 mg/chromium element, and the fluorine element is 5 mg/chromium element, and the fluorine element is 15 mg/chromium element is 5mg fluoride.

2. The corrosion resistant metal-plastic composite film according to claim 1, wherein the material of the metal layer is at least one of an aluminum alloy, a stainless steel, a titanium steel, or a nickel plated steel sheet.

3. The corrosion-resistant metal-plastic composite film according to claim 1, wherein the corrosion-resistant layer is formed of a corrosion-resistant liquid formed by mixing a trivalent chromium compound, an inorganic acid and an organic resin with water or an organic solvent, wherein the trivalent chromium compound accounts for 1.9 to 6% of the corrosion-resistant liquid, the inorganic acid accounts for 0.3 to 6% of the corrosion-resistant liquid, the organic resin accounts for 0.6 to 6% of the corrosion-resistant liquid, and the water or the organic solvent accounts for 78.6 to 97.2% of the corrosion-resistant liquid, wherein the trivalent chromium compound is chromium fluoride, the inorganic acid is hydrofluoric acid, the organic resin is polyvinyl alcohol resin, and the organic solvent is at least one of isopropanol, ethanol, and ethylene glycol butyl ether.

4. The corrosion-resistant metal-plastic composite film according to claim 3, wherein the corrosion-resistant liquid contains a bridging agent, wherein the bridging agent is composed of at least one of an amino resin, a melamine resin, a phenol resin, an epoxy compound, a blocked isocyanate compound, an oxazoline compound, a carbodiimide compound, a condensate of formaldehyde and an alkyl monohydric alcohol having 1 to 4 carbon atoms, a condensate of carbonic acid and formaldehyde.

5. The corrosion-resistant metal-plastic composite film according to claim 4, wherein the bridging agent is contained in an amount of 0.05 to 15% based on the solid content of the corrosion-resistant liquid, or the bridging agent is contained in an amount of 0.01 to 30% based on the solid content of the corrosion-resistant layer.

6. The corrosion-resistant metal-plastic composite film according to claim 1, wherein the corrosion-resistant layer comprises a titanium (Ti) compound and a zirconium (Zr) compound, the content ratio of the titanium (Ti) compound is not more than 0.6%, and the content ratio of the zirconium (Zr) compound is not more than 2.8%.

7. The corrosion resistant metal-plastic composite film according to claim 6, wherein said titanium (Ti) compound is titanium fluoride and said zirconium (Zr) compound is at least one of zirconium fluoride or zirconium nitrate.

8. The corrosion resistant metal-plastic composite film of claim 1, further comprising a first resin layer and a second resin layer, wherein the first resin layer is disposed on one side of the metal layer, and the second resin layer is disposed on the other side of the metal layer.

9. The corrosion resistant metal-plastic composite film of claim 8, wherein said first resin layer is bonded to said metal layer with a first adhesive.

10. The corrosion-resistant metal-plastic composite film according to claim 9, wherein the material of the first adhesive is at least one of block-copolymerized polypropylene resin (B-PP), random-copolymerized polypropylene resin (R-PP) and homo-polymerized polypropylene resin (H-PP), and the polypropylene (PP) content in the block-copolymerized polypropylene resin (B-PP), random-copolymerized polypropylene resin (R-PP) and homo-polymerized polypropylene resin (H-PP) is not less than 50%.

11. The corrosion resistant metal-plastic composite film of claim 8, wherein said second resin layer is bonded to said metal layer with a second adhesive.

12. The corrosion resistant metal-plastic composite film of claim 8, wherein the first resin layer is a heat-welded resin layer, and wherein the material of the first resin layer is composed of at least one of a polyolefin, a cyclic polyolefin, or a modified polyolefin.

13. The corrosion resistant metal-plastic composite film of claim 12, wherein the modified polyolefin is at least one of a aliphatic carboxylic acid modified polyolefin, a carboxylic acid modified cyclic polyolefin, a methacrylic acid modified polyolefin, an acrylic acid modified polyolefin, a crotonic acid modified polyolefin, or an imide modified polyolefin.

14. The corrosion resistant metal-plastic composite film according to claim 8, wherein the side of the metal layer to which the first resin layer is bonded forms the corrosion resistant layer.