When a lubricant is present on the surface of the substrate layer 1, the coating amount is not particularly limited in the present invention, and examples thereof preferably include about 3 mg/m²or more and more preferably about 4-30 mg/m². The lubricant present on the surface of the substrate layer may be a lubricant that leaks out of the lubricant contained in the resins constituting the substrate layer, or may be a lubricant coated on the surface of the substrate layer.

The thickness of the substrate layer is not particularly limited in the present invention, as long as it functions as a substrate, and examples of the thickness include, for example, about 3-50 μm, and preferably about 10-35 μm. When the substrate layer is a laminate with 2 or more layers of resin films, the thickness of each resin film constituting each layer is preferably about 2-30 μm.

First Bonding Layer 2:

The first bonding layer 2 is a layer disposed between the substrate layer 1 and the barrier layer 5 as needed for the purpose of improving adhesion therebetween.

The first bonding layer 2 is formed of an adhesive capable of bonding the substrate layer 1 and the barrier layer 5. The adhesive used for forming the bonding layer 2 is not limited in the present invention, and may be, for example, a bicomponent curable adhesive (bicomponent adhesive), and in addition, may also be a monocomponent curable adhesive (monocomponent adhesive). Moreover, the adhesive used for forming the first bonding layer 2 may be any of a chemical reaction type, a solvent volatilization type, a hot-melt type, a hot-press type and the like. In addition, the first bonding layer 2 may consist of one or more layers.

Specific examples of adhesive components contained in the adhesive include polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene isophthalate and copolymerized polyester; polyether; polyurethane; epoxy resin; phenol-formaldehyde resin; polyamides such as nylon 6, nylon 66, nylon 12, and copolymerized polyamide; polyolefin-based resins such as polyolefin, cyclic polyolefin, acid-modified polyolefin and acid-modified cyclic polyolefin; polyvinyl acetate; cellulose; (meth)acrylic resins; polyimide; polycarbonate; amino resins such as urea resin and melamine resin; rubbers such as chloroprene rubber, nitrile rubber and styrene-butadiene rubber; silicone resins, and the like. Only one of these adhesive components may be used, or 2 or more of these adhesive components may be used in combination. Among these adhesive components, the polyurethane adhesive is preferable.

Examples of the polyurethane adhesive include, for example, a polyurethane adhesive comprising a main agent containing a polyol compound and a curing agent containing an isocyanate compound.

In addition, other components are allowed for addition into the first bonding layer 2 as long as they do not interfere with the adhesion, including a colorant, a thermoplastic elastomer, a tackifier, a filler and the like. The packaging material for the battery can be colored by adding a colorant in the first bonding layer 2. Known colorants such as pigments and dyes can be used. In addition, the colorant may be used alone, or may also be used in a combination of two or more.

The pigment is not particularly limited as long as the adhesion range of the first bonding layer 2 is not impaired. Examples of organic pigment include, for example, an azo-type pigment, a phthalocyanine-type pigment, a quinacridone-type pigment, an anthraquinone-type pigment, a dioxazine-type pigment, a thioindigo-type pigment, a perylene-type pigment, an isoindoline-type pigment and the like, and examples of inorganic pigment include, for example, a carbon black-type pigment, a titanium oxide-type pigment, a cadmium-type pigment, a lead-type pigment, an isoindoline-type pigment and the like. Among these colorants, carbon black-type pigment is preferable, for example, in order to make the appearance of the packaging material for the battery black.

The average particle size of the pigment is not particularly limited, and examples include, for example, about 0.05-5 μm, and preferably about 0.08-2 μm. In addition, the average particle size of the pigment is a median particle size measured by a laser diffraction/scattering particle size distribution measuring apparatus.

The content of the pigment in the first bonding layer 2 is not particularly limited as long as the packaging material for the battery is colored, and examples include, for example, about 5%-60%, and preferably 10%-40% of the first bonding layer 2.

The thickness of the bonding layer 2 is not particularly limited as long as the substrate layer 1 and the barrier layer 5 can be bonded to each other; examples of the lower limit of the thickness include, for example, about 1 μm or more or about 2 μm or more, examples of the upper limit of the thickness include, for example, about 10 μm or less or about 5 μm or less, and examples of a preferable range of the thickness include, for example, about 1-10 μm or about 1-5 μm.

Colored Layer 3:

In some embodiments of the present invention, a colored layer 3 is also included.

The colored layer 3 is a layer disposed between the substrate layer 1 and the barrier layer 5 according to practical need. When the first bonding layer 2 is provided, the colored layer 3 may also be disposed between the substrate layer 1 and the first bonding layer 2, or between the first bonding layer 2 and the barrier layer 5. In addition, the colored layer 3 may also be disposed outside the substrate layer 1. The packaging material for the battery may be colored by providing the colored layer 3.

The colored layer 3 may be formed by, for example, coating the surface of the substrate layer 1, the surface of the first bonding layer 2, or the surface of the barrier layer 5 with an ink containing a colorant. Known colorants such as pigments and dyes can be used. In addition, only one of the colorants may be used, or 2 or more of these colorants may be used in combination.

Specific examples of the colorant contained in the colored layer 3 may be the same colorant as that exemplified for the first bonding layer 2.

Barrier Layer 5:

In the outer packaging material for the battery, the barrier layer 5 is a layer at least capable of preventing moisture penetration.

In some embodiments of the present invention, the barrier layer 5 consists of an aluminum alloy foil, and the aluminum alloy foil consists of one or more layers; the aluminum alloy foil comprises 1.2% or more of Fe and 1% or more of Mg by mass percentage; after the aluminum alloy foil is annealed, a large amount of Mg is precipitated from the aluminum alloy foil, and a ratio of precipitated Mg to precipitated Al is 2-4.

Specifically, the aluminum alloy foil also comprises: 0.01%-0.2% of Si, 0.02%-0.06% of Sb, 0.01% or less of Mn, 0.03% or less of Zn and 0.01% or less of Cr in mass percentage.

Further, the aluminum alloy foil comprises 1%-2% mass percentage of Mg.

Further, the aluminum alloy foil comprises 1.2%-2% mass percentage of Fe.

Further, the aluminum alloy foil has an average particle size of 10 μm or less.

Preferably, the aluminum alloy foil has an average particle size of 5 μm or less.

Further, 90% or more of the particles of the aluminum alloy foil have a particle size in a range of 0.01-30 μm.

Preferably, 90% or more of the particles of the aluminum alloy foil have a particle size in a range of 0.01-25 μm.

Even further, there are 70% or more of the particles of the aluminum alloy foil having a particle size smaller than an average particle size of the aluminum alloy foil.

Further, the aluminum alloy foil has a thickness of 20-100 μm.

In some embodiments of the present invention, the aluminum alloy foil may be a composite layer with 2 or more layers, and the composite layer may be calendered in vacuum, or may be calendered in a normal environment. Generally, the composite layer is not subjected to any special treatment before being calendered to a desired thickness.

First corrosion-resistant layer 4/Second corrosion-resistant layer 6:

When the barrier layer 5 is a metal foil, a corrosion-resistant film is preferably adhered to at least one side of the barrier layer 5 opposite to the substrate layer 1 to prevent problems such as dissolution and corrosion. Optionally, corrosion-resistant films may adhere to both sides of the barrier layer 5 respectively. The corrosion-resistant film refers to, for example, an anti-corrosion thin film formed on the barrier layer 5 by treating a surface of the barrier layer 5 via hydrothermal treatment (such as boehmite treatment), chemical treatment, anodic oxidation treatment, electroplating treatment such as nickel or chromium treatment, or anti-corrosion coating treatment. Any one of the treatments for forming the corrosion-resistant film may be performed alone, or 2 or more of the treatments may be performed in combination. The treated film is not limited to one layer, and may also be a combination of more than one layer. Among these treatments, the hydrothermal treatment and the anodic oxidation treatment are treatments in which the surface of the metal foil is dissolved by a treating agent to form a metal compound having excellent corrosion resistance. In addition, these treatments are sometimes included within the definition of chemical treatment. When a general situation where the barrier layer 5 comprises at least one corrosion-resistant film, the barrier layer 5 is defined to include also said at least one corrosion-resistant film.

When the packaging material for the battery is formed, the corrosion-resistant film prevents the separation of the barrier layer 5 (for example, aluminum alloy foil) and the substrate layer 1, and avoids hydrogen fluoride generated by the reaction of electrolyte and moisture, thereby preventing dissolution and corrosion of the surface of the barrier layer 5, particularly, dissolution and corrosion of aluminum oxide present on the surface of the barrier layer 5 when the barrier layer is an aluminum alloy foil, and improving adhesion (wettability) on the surface of the barrier layer 5, which has an effect of preventing the separation of the substrate layer 1 and the barrier layer 5 during heat sealing and formation.

Many types of corrosion-resistant films formed by chemical treatment are known, and examples thereof include, for example, corrosion-resistant films containing at least one of a phosphate, a chromate, a fluoride, a triazine thiol compound, a rare earth oxide and the like.

Examples of chemical treatments using a phosphate or a chromate mainly include, for example, chrome plating treatment with chromic acids, chrome plating treatment with phosphoric acids, phosphoric acid-chromate treatment, chromate treatment, and the like, and examples of chromium compound used in these treatments mainly include, for example, chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium biphosphate, chromium acetoacetate, chromium chloride, chromium potassium sulfate and the like. Examples of phosphorus compound used in these treatments mainly include, for example, sodium phosphate, potassium phosphate, ammonium phosphate, polyphosphoric acid and the like. Examples of chromate treatments mainly include chromate etching treatment, chromate electrolytic treatment, chromate coating treatment and the like, and preferably chromate coating treatment. In the chromate coating treatment, at least the inner side of the barrier layer 5 (for example, the aluminum alloy foil) is first subjected to a degreasing treatment by common methods such as alkali immersion, electrolytic cleaning, acid cleaning, electrolytic acid cleaning, oxygen activation and the like. Then, the degreased surface is coated by treatment solution via a known coating method such as roll coating, gravure coating, or immersion using a treatment solution, and then dried. The treatment solution includes a treatment solution mainly containing a metallic phosphate such as Cr (chromium) phosphate, Ti (titanium) phosphate, Zr (zirconium) phosphate, or Zn (zinc) phosphate and a mixture of these metallic salts, a treatment solution mainly containing a non-metallic phosphate and a mixture of these non-metallic salts, or a treatment solution containing a mixture of the above materials and a synthetic resin. Various solvents such as water, alcohol solvents, hydrocarbon solvents, ketone solvents, ester solvents, and ether solvents, and preferably water, may be used for the treatment solution. In addition, a water-soluble macromolecule such as phenol or polyacrylic acid can be selected as a resin component used herein.

As an example of the corrosion-resistant film, a phosphoric acid in which particulate substance of a metallic oxide such as aluminum oxide, titanium oxide, cerium oxide and tin oxide, or barium sulfate is dispersed, is applied to the surface of the barrier layer 5, sintered at 150° C. or greater to form the corrosion-resistant film.

Other examples of the corrosion-resistant film mainly include a thin film formed by anti-corrosion coating treatment containing at least one component selected from a rare-earth element oxide sol, an anionic polymer and a cationic polymer. Coating agent may further contain phosphoric acid or a phosphate, or a crosslinking agent for crosslinking polymer. In the rare-earth element oxide sol, fine particles (for example, particles having an average particle size of 100 nm or less) of a rare-earth element oxide are dispersed in a liquid dispersion medium. Examples of rare-earth element oxide mainly include cerium oxide, yttrium oxide, neodymium oxide, lanthanum oxide and the like, and cerium oxide is preferred from the viewpoint of further improving adhesion. Only one of the rare-earth element oxides contained in the corrosion-resistant film may be used, 2 or more of the rare-earth element oxides may be used in combination. For example, various solvents such as water, alcohol solvents, hydrocarbon solvents, ketone solvents, ester solvents, and ether solvents, and preferably water, may be used as the liquid dispersion medium of the rare-earth element oxide sol. Examples of the cationic polymer mainly include polyethyleneimine, an ionic polymer complex composed of polyethyleneimine and a polymer having carboxylic acid, a primary amine-grafted acrylic resin in which a primary amine is grafted to an acrylic backbone, polyallylamine or a derivative thereof, and aminophenol. In addition, the anionic polymer is preferably a copolymer mainly containing poly(meth)acrylic acid or a salt thereof, or (meth)acrylic acid or a salt thereof. The crosslinking agent is preferably at least one selected from a compound having any functional group of an isocyanate group, a glycidyl group, a carboxyl group and an oxazoline group, and a silane coupling agent. The phosphoric acid or phosphate is preferably condensed phosphoric acid or a condensed phosphate.

The corrosion-resistant film may be further laminated with at least one of a cationic polymer and an anionic polymer to form a laminated structure, if necessary. Examples of the cationic polymer and the anionic polymer mainly include the above-mentioned polymers.

The thickness of the corrosion-resistant film is not particularly limited, but is preferably 1 nm to 2.0 μm, and more preferably 1 nm to 1 μm, from the viewpoint of the cohesion of the corrosion-resistant film and the adhesion to the barrier layer 5 or a hot-melt resin layer.

The chemical treatment is conducted in the following manner: a solution containing a compound used for the formation of a corrosion-resistant film is applied to the surface of the barrier layer 5 through bar coating, roll coating, gravure coating, immersion or the like, and then the barrier layer 5 is heated to 70-200° C. In addition, the barrier layer 5 may also be subjected to degreasing through alkali immersion, electrolytic cleaning, acid cleaning, electrolytic acid cleaning or the like before the barrier layer 5 is subjected to the chemical treatment. When degreasing treatment is performed as described above, the chemical treatment on the surface of the barrier layer 5 can be conducted more efficiently.

Second Bonding Layer 7:

The second bonding layer 7 is an intermediate layer disposed to firmly adhere the barrier layer 5 and the hot-melt connecting layer 8.

The second bonding layer 7 is formed of a resin capable of adhering the barrier layer 5 and the hot-melt connecting layer 8. As the resin used for forming the second bonding layer 7, a resin with the same adhesive mechanism, the same adhesive composition and the like as those of the adhesive exemplified in the first bonding layer 2 may be used. In addition, polyolefin-based resins such as polyolefin, cyclic polyolefin, carboxylic acid-modified polyolefin, and carboxylic acid-modified cyclic polyolefin exemplified in the hot-melt connecting layer 8 as described below may also be used. From the viewpoint of improving the adhesion between the barrier layer 5 and the hot-melt connecting layer 8, the polyolefin is preferably a carboxylic acid-modified polyolefin, and more preferably a carboxylic acid-modified polypropylene. That is, the resin forming the second bonding layer 7 may or may not contain a polyolefin backbone, and preferably contains a polyolefin backbone. Whether the resin forming the second bonding layer 7 contains a polyolefin backbone or not can be analyzed by, for example, infrared spectrophotometry, gas chromatography-mass spectrometry, or the like, and the analysis method is not particularly limited.

The second bonding layer 7 may also be a cured product of a resin composition containing an acid-modified polyolefin and a curing agent, with a view of reducing the thickness of the packaging material for the battery and improving the forming stability thereof. The acid-modified polyolefin is preferably the same as the carboxylic acid-modified polyolefin and the carboxylic acid-modified cyclic polyolefin exemplified in the hot-melt connecting layer.

The curing agent is not particularly limited as long as it is a curing agent for curing the acid-modified polyolefin. Examples of the curing agent include, for example, an epoxy curing agent, a polyfunctional isocyanate curing agent, a carbodiimide curing agent, an oxazoline curing agent and the like.

The epoxy curing agent is not particularly limited as long as it is a compound having at least one epoxy group. Examples of the epoxy curing agent include, for example, epoxy resins such as bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, novolak glycidyl ether, glycerol polyglycidyl ether and polyglycerol polyglycidyl ether.

The polyfunctional isocyanate curing agent is not particularly limited as long as it is a compound having two or more isocyanate groups in the molecule. Examples of the polyfunctional isocyanate curing agent include, for example, isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), components after polymerization or addition of the above substances, and reactants of such mixtures with other polymers.

The carbodiimide curing agent is not particularly limited as long as it is a compound having at least one carbodiimide group (—N═C═N—) in the molecule. The carbodiimide curing agent is preferably a polycarbodiimide compound having at least two or more carbodiimide groups.

The oxazoline curing agent is not particularly limited as long as it is a compound having an oxazoline backbone. Examples of the oxazoline curing agent include, for example, the epoxy series manufactured by Nippon Shokubai Co., Ltd.

The curing agent may also be composed of two or more compounds, from the viewpoint of improving the adhesion between the second bonding layer 7 and the hot-melt connecting layer 8.

The thickness of the second bonding layer 7 is not particularly limited as long as it achieves the required functions of the second bonding layer 7. However, when the adhesive exemplified in the first bonding layer 2 is used, the thickness is preferably, for example, about 1-10 μm, and more preferably about 1-5 μm. When the resin exemplified in the hot-melt connecting layer 8 is used, the thickness is preferably, for example, about 2-50 μm, and more preferably about 10-40 μm. If the cured product containing the acid-modified polyolefin and the curing agent is used, the thickness is preferably, for example, 30 μm or less, more preferably about 0.1-20 μm, and even more preferably about 0.5-5 μm. It should be noted that, when the second bonding layer 7 is a cured product of a resin composition containing the acid-modified polyolefin and the curing agent, the second bonding layer 7 can be formed by applying the resin composition and then curing the resin composition by heating or the like.

Hot-Melt Connecting Layer 8:

The hot-melt connecting layer 8 is the innermost layer, and is a layer (a heat-sealing layer) that exerts the function of a hot-melting resin layer to seal the battery elements after being connected end-to-end through hot-melting to enclose the batter elements when the battery is assembled.

The resin forming the hot-melt connecting layer 8 is not particularly limited as long as it can be hot-melted, and a resin containing a polyolefin backbone such as polyolefin or acid-modified polyolefin is preferred.

Specific examples of polyolefin include, for example, polyethylene such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; ethylene-α-olefin copolymers; polypropylene such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene); propylene-α-olefin copolymers; terpolymers of ethylene-butene-propylene, and the like. Among them, polypropylene is preferred. The polyolefin resin used as a copolymer may be a block copolymer, or may also be a random copolymer. Only one of these polyolefin-based resins may be used, or 2 or more of these polyolefin-based resins may be used in combination.

The acid-modified polyolefin is a polymer modified by block polymerization or graft polymerization of polyolefins with an acid component. Examples of the acid-modified polyolefin include the above polyolefin, a copolymer obtained by copolymerizing a polar molecule such as acrylic acid or methacrylic acid with the above polyolefin, a polymer such as a crosslinked polyolefin, or the like. In addition, examples of the acid component used for acid modification include, for example, carboxylic acids and sulfonic acids such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride, and anhydride thereof.

The hot-melt connecting layer 8 may consist of one resin alone, or may also consist of a polymer blend in which two or more resins are combined. Moreover, the hot-melt connecting layer 8 may consist of only 1 layer, or may also consist of two or more layers of the same or different resins.

The hot-melt connecting layer 8 may also contain a slipping agent or the like according to practical need. When the hot-melt connecting layer 8 contains a slipping agent, the formability of the outer packaging material for the battery can be improved. The slipping agent is not particularly limited, and may be selected and used according to common technical knowledge. Only one of the slipping agents may be used, or two or more slipping agents may be used in combination.

The slipping agent is not particularly limited, and preferably includes an amide-based slipping agent. Only one of the slipping agents may be used, or two or more of the slipping agents may be used in combination.

When a lubricant is present on the surface of the hot-melt connecting layer 8, the amount of the lubricant is not particularly limited. However, from the viewpoint of improving the formability of the material for the battery packaging, the amount of lubricant is preferably, 10-50 mg/m², and more preferably 15-40 mg/m².

The slipping agent present on the surface of the hot-melt connecting layer 8 may be a slipping agent that leaks out of the resins constituting the hot-melt connecting layer 8, or may also be a slipping agent applied to the surface of the hot-melt connecting layer 8.

The thickness of the hot-melt connecting layer 8 is not particularly limited as long as it satisfies the performance of the hot-melt resin layers after being connected end-to-end through hot-melting to enclose the battery elements and thus exerts the function of sealing the battery elements. The thickness is, for example, about 100 μm or less, and preferably about 15-85 μm.

The hot-melt connecting layer 8 may also contain a component such as an antioxidant or the like according to practical need. The hot-melt connecting layer 8 containing an antioxidant can suppress thermal deterioration during the manufacturing process. The type of antioxidant is not particularly limited, and may be selected and used according to common technical knowledge. Only one antioxidant may be used, or two or more antioxidants may be used in combination.

The present invention is described in detail below by the description of examples.

In the following examples and comparative examples, the performance parameters were determined as follows:

- (1) Alloy composition was measured by photoelectric emission spectrochemical analysis in accordance with the JIS Z 2611 standard.
- (2) The particle size of the crystals was observed by EBSD (electron backscatter diffraction) after slicing the electrolytic grinding material.
- (3) The contents of Mg, Fe and Al on the surface of the aluminum alloy foil could be measured by X-ray photoelectron spectroscopy (XPS).
- (4) Tensile strength

The tensile strength was measured using a tensile test apparatus after the aluminum-plastic composite film was prepared into a straight strip, with a sample size of 100×15 mm at the tensile rate of 50 mm/min.

- (5) Forming depth

The forming size was 80×70 mm, the pressing pressure was 0.8 MPa, the radius of the corner was r=1.0 mm, the radius of the convex edge angle was r=1.0 mm, and the gap between the convex and concave portions was 0.51 mm.

- (6) Test of corrosion resistance

The aluminum alloy was used as the anode, and the Li alloy was used as the cathode. An external power supply was used for charging with the charging voltage at 1 V, and the solvent was a 1 mol/L of LiPF₆EC/DEC/DMC lithium-ion battery electrolyte solution. After charging for 3 h, whether the aluminum alloy was corroded or not was verified by checking whether a current was generated or not through a potentiometer and visually observing whether the Li—Al alloy was generated on the anode or not.

Example 1

Substrate Layer:

A 2-stage asynchronous biaxially stretched nylon film with a thickness of 25 μm was used.

Aluminum Alloy Foil Layer:

A one-layer aluminum alloy foil layer, with a thickness of 40 μm, containing 1% of Mg, 1.2% of Fe, 0.1% of Si, and 0.02% of Sb by mass percentage was used, and after annealing, the precipitation ratio of Mg to Al on the surface of the aluminum alloy foil was 2.

The substrate layer was subjected to a corona treatment, and the aluminum alloy foil layer was rolled with dry iron on the substrate layer. The dull side of the aluminum alloy foil was coated with a bicomponent polyurethane adhesive (a polyol compound and an aromatic isocyanate compound) to form the first bonding layer 2 (3 μm) on the aluminum alloy foil. The first bonding layer 2 on the dull side of the aluminum alloy foil was compounded with the substrate layer 1, and then aging at 60° C. for 3 days to form a semi-finished product consisting of substrate layer (25 μm), first bonding layer (3 μm), and aluminum alloy foil layer (40 μm). Both sides of the aluminum alloy foil layer were already chemically treated in advance.

An anhydrous maleic anhydride-modified polypropylene resin with a weight-average molecular mass of 70,000, a melting point of 145° C. and an acid value of 4.5 mg KOH/g was dissolved in water, and then an epoxy resin and a methanesulfonic acid resin was added, to form a bonding resin. The shiny side of the aluminum alloy foil layer in the semi-finished product was coated with the bonding resin aqueous solution, and then dried at a drying temperature of 150° C. to form the second bonding layer 7.

An internal hot-melt connecting resin (CPP) as the hot-melt connecting layer 8 was composed of three layers, including:

- a resin layer in contact with the second bonding layer 7: a layer composed of randomly copolymerized polypropylene with a melting point of 162° C. and an melt flow rate (MFR) (230° C.) of 5.5 g/10 min;
- an intermediate resin layer: a mixture layer formed of, by weight percentage, 50% of a block copolymerized polypropylene with a melting point of 162° C. and an MFR (230° C.) of 2 g/10 min, 20% of a randomly copolymerized polypropylene with a melting point of 155° C. and an MFR (230° C.) of 5 g/10 min, 20% of a polymer elastomer composed of propylene and butene with a melting point of 160° C., an MFR (230° C.) of 9.5 g/10 min and a density of 0.87 g/cm³, and 10% of a non-crystalline propylene-based elastomer with an MFR (230° C.) of 3 g/10 min; and
- an innermost resin layer: a layer composed of a randomly copolymerized polypropylene with a melting point of 145° C. and an MFR (230° C.) of 12 g/10 min;
- wherein a thickness ratio of the three-layer internal hot-melt connecting resin from the resin layer in contact with the second bonding layer 7 to the innermost resin layer was 3:6:1.

The surface of the 40-μm CPP film was subjected to a corona treatment, and then heat-compounded with the second bonding layer 7 at 160° C., followed by thermal treatment at 160° C. for 30 s. Thus, a composite-finished product comprising substrate layer (25 μm), first bonding layer (3 μm), aluminum alloy foil layer (40 μm), second bonding layer (1.5 μm), and hot-melt connecting layer (40 μm) was formed.

Meanwhile, the surface of the substrate layer was coated with a Slip agent (slipping agent). The slip film layer was a 10% (concentration) erucamide solution, and after drying at a certain temperature, the coating amount of erucamide on the surface of the substrate layer was 10 mg/m².

Example 2

Substrate Layer:

A 2-stage asynchronous biaxially stretched polybutylene terephthalate (PBT) film with a thickness of 25 μm was used as the substrate layer.

Aluminum Alloy Foil Layer:

A one-layer aluminum alloy foil layer, with a thickness of 40 μm, containing 1.5% of Mg, 1.5% of Fe, 0.1% of Si, and 0.02% of Sb by mass percentage was used, and after annealing, the precipitation ratio of Mg to Al on the surface of the aluminum alloy foil was 3.1.

A composite-finished product of substrate layer (25 μm), first bonding layer (3 μm), aluminum alloy foil layer (40 μm), second bonding layer (1.5 μm), and hot-melt connecting layer (40 μm) was formed using the method in Example 1. Meanwhile, the surface of the substrate layer was also coated with the same amount of the Slip agent as in Example 1.

Example 3

Substrate Layer:

A 2-stage asynchronous biaxially stretched nylon film with a thickness of 25 μm was used as the substrate layer.

Aluminum Alloy Foil Layer:

A one-layer aluminum alloy foil layer, with a thickness of 40 μm, containing 2% of Mg, 2% of Fe, 0.1% of Si, and 0.02% of Sb by mass percentage was used, and after annealing, the precipitation ratio of Mg to Al on the surface of the aluminum alloy foil was 4.

A composite-finished product of substrate layer (25 μm), first bonding layer (3 μm), aluminum alloy foil layer (40 μm), second bonding layer (1.5 μm), and hot-melt connecting layer (40 μm) was formed using the method in Example 1. Meanwhile, the surface of the substrate layer was also coated with the same amount of the Slip agent as in Example 1.

Example 4

Substrate Layer:

A 2-stage asynchronous biaxially stretched polybutylene terephthalate (PBT) film with a thickness of 25 μm was used as the substrate layer.

Aluminum Alloy Foil Layer:

A 3-layer composite aluminum alloy foil comprising a layer of Mg—Al alloy foil, a layer of 8021 Al foil, and another layer of Mg—Al alloy foil was used. The intermediate layer, i.e. the 8021 Al foil, contained 1.5% of Fe and 0.08% of Si by mass percentage. Each of both layers of Mg—Al alloy foil that were in contact with the substrate layer 1 and the hot-melt connecting layer 8 respectively had a thickness of 10 μm, and each contained 1.5% of Mg, 1.5% of Fe, 0.01% of Si and 0.04% of Sb by mass percentage; and after annealing, the precipitation ratio of Mg to Al on the surface of the aluminum alloy foil was 3.1.

The substrate layer was subjected to a corona treatment, and the aluminum alloy foil layer was rolled with dry iron on the substrate layer. One side of the aluminum alloy foil was coated with a bicomponent polyurethane adhesive (a polyester polyol compound and an aromatic isocyanate compound) to form the first bonding layer 2 (3 μm) on the aluminum alloy foil. The first bonding layer 2 on one side of the aluminum alloy foil was compounded with the substrate layer 1, and then aging at 60° C. for 3 days to form a semi-finished product consisting of substrate layer (25 μm), bonding layer (3 μm), and aluminum alloy foil layer (40 μm). Both sides of the aluminum alloy foil layer were already chemically treated in advance to form the corrosion-resistant layers 4 and 6.

The hot-melt resin used for the second bonding layer 7 was anhydrous maleic anhydride-modified polypropylene, and the second bonding layer 7 with a thickness of 20 μm was formed on a treated surface of the aluminum alloy foil. Further, the second bonding layer was compounded with a hot-melt connecting resin with a thickness of 20 μm. The second bonding layer 7 and the hot-melt connecting layer 8 were compounded on another side of the aluminum alloy foil by melting and co-extruding. The second bonding layer 7 is a mixture consisting of 60% (by weight percentage) of anhydrous maleic anhydride-modified randomly copolymerized polypropylene (the modification degree of the randomly copolymerized polypropylene by the anhydrous maleic anhydride was 10%) with a melting point of 140° C. and an MFR (230° C.) of 5 g/10 min, 24% (by weight percentage) of a copolymer elastomer of propylene and butene with a melting point of 160° C., an MFR (230° C.) of 2.6 g/10 min and a density of 0.87 g/cm³, 8% (by weight percentage) of a crystalline copolymer elastomer of ethylene and propylene with a melting point of 130° C., an MFR (230° C.) of 9.5 g/10 min and a density of 0.91 g/cm³, and 8% (by weight percentage) of a low-density polyethylene with a melting point of 105° C. and an MFR (230° C.) of 12 g/10 min.

An internal hot-melt connecting resin as the hot-melt connecting layer 8 was composed of two layers, including:

- a resin layer in contact with the second bonding layer 7: a mixture layer formed, by weight percentage, of 62% of randomly copolymerized polypropylene with a melting point of 155° C. and an MFR (230° C.) of 4 g/10 min, 33% of a non-crystalline propylene-based elastomer, and 5% of a low-density polyethylene with a melting point of 110° C. and an MFR (230° C.) of 7.5 g/10 m; and
- an innermost resin layer: a layer composed of randomly copolymerized polypropylene with a melting point of 155° C. and an MFR (230° C.) of 15 g/10 m;
- wherein a thickness ratio of the resin layer in contact with the second bonding layer 7 to the innermost resin layer was 8:2.

After the semi-finished product consisting of substrate layer (25 μm), first bonding layer (3 μm), and aluminum alloy foil layer (40 μm) was compounded with the second bonding layer 7 and the hot-melt connecting layer 8, a thermal treatment was performed at 180° C. for 2 s.

Thus, a composite-finished product comprising substrate layer (25 μm), first bonding layer (3 μm), aluminum alloy foil layer (40 μm), second bonding layer (20 μm), and hot-melt connecting layer (20 μm) was formed.

Meanwhile, the surface of the substrate layer was coated with the same amount of the Slip agent as in Example 1.

Example 5

Substrate Layer:

A 2-stage asynchronous biaxially stretched polybutylene terephthalate (PBT) film with a thickness of 25 μm was used as the substrate layer.

Aluminum Alloy Foil Layer:

A one-layer aluminum alloy foil layer, with a thickness of 100 μm, comprising 1.5% of Mg, 1.5% of Fe, 0.01% of Si, and 0.04% of Sb by mass percentage was used, and after annealing, the precipitation ratio of Mg to Al on the surface of the aluminum alloy foil was 3.

A composite-finished product comprising substrate layer (25 μm), first bonding layer (3 μm), aluminum alloy foil layer (100 μm), second bonding layer (1.5 μm), and hot-melt connecting layer (40 μm) was formed using the method in Example 1. Meanwhile, the surface of the substrate layer was also coated with the same amount of the Slip agent as in Example 1.

Example 6

Substrate Layer:

A 2-stage asynchronous biaxially stretched polyethylene terephthalate (PET) with a thickness of 12 μm and a 2-stage asynchronous biaxially stretched nylon with a thickness of 15 μm were used for the substrate layer. Specifically, one surface of the PET was subjected to a corona treatment in advance, and the corona-treated surface of the PET was coated with a bicomponent polyurethane adhesive (a polyol compound and an aromatic isocyanate compound) to form a first bonding layer (3 μm). The first bonding layer on the PET was compounded with the nylon which had been subjected to a corona treatment to form a composite substrate layer consisting of PET (12 μm), first bonding layer (3 μm), and nylon layer (15 μm).

Aluminum Alloy Foil Layer:

A 2-layer composite aluminum alloy foil of Mg—Al alloy foil and 8079 Al foil (in a thickness ratio of 1:9) was used, and the total thickness of the composite aluminum alloy foil was 40 μm. The Mg—Al alloy foil layer contained 1% of Mg, 1.5% of Fe, 0.1% of Si and 0.02% of Sb by mass percentage, and after annealing, the precipitation ratio of Mg to Al on the surface of the composite aluminum alloy foil was 2.1.

A side of the nylon layer of the composite substrate layer that was in contact with the 8079 Al foil of the composite aluminum alloy foil layer was subjected to a corona treatment in advance, and then aging at 60° C. for 3 days to form a semi-finished composite layer of PET (12 μm), first bonding layer (3 μm), nylon layer (15 μm), second bonding layer (3 μm), and aluminum alloy foil layer (40 μm).

The internal hot-melt connecting resin being the hot-melt connecting layer 8 was composed of 3 layers, including:

- a resin layer in contact with the aluminum alloy foil layer: a mixture consisting of 60% (by weight percentage) of anhydrous maleic anhydride-modified randomly copolymerized polypropylene (the modification degree of the randomly copolymerized polypropylene by the anhydrous maleic anhydride was 10%) with a melting point of 140° C. and an MFR (230° C.) of 5 g/10 min, 24% (by weight percentage) of a copolymer elastomer of propylene and butene with a melting point of 160° C., an MFR (230° C.) of 2.6 g/10 min and a density of 0.87 g/cm³, 8% (by weight percentage) of a crystalline copolymer elastomer of ethylene and propylene with a melting point of 130° C., an MFR (230° C.) of 9.5 g/10 min and a density of 0.91 g/cm³, and 8% (by weight percentage) of a low-density polyethylene with a melting point of 105° C. and an MFR (230° C.) of 12 g/10 min;
- an intermediate resin layer: a mixture layer formed of 62% (by weight percentage) of randomly copolymerized polypropylene with a melting point of 155° C. and an MFR (230° C.) of 4 g/10 min, 33% (by weight percentage) of a non-crystalline propylene-based elastomer, and 5% (by weight percentage) of a low-density polyethylene with a melting point of 110° C. and an MFR (230° C.) of 7.5 g/10 min, by weight;
- an innermost resin layer: a layer composed of randomly copolymerized polypropylene with a melting point of 155° C. and an MFR (230° C.) of 15 g/10 m;
- wherein the thickness ratio of the resin layer in contact with the aluminum alloy foil layer to the intermediate resin layer to the innermost resin layer was 10:8:2.

After the internal hot-melt connecting resin being the hot-melt connecting layer 8 was compounded onto a surface of the Mg—Al alloy foil layer of the aluminum alloy foil layer by melting and co-extruding in a semi-finished product comprising the substrate layer (25 μm), the second bonding layer (3 μm), and the aluminum alloy foil layer (40 μm), a thermal treatment was performed at 180° C. for 2 s.

Thus, a composite-finished product comprising the substrate layer (25 μm), the second bonding layer (3 μm), the aluminum alloy foil layer (40 μm), and the hot-melt connecting layer (40 μm) was formed.

Meanwhile, the surface of the substrate layer was coated with the same amount of the Slip agent as in Example 1.

Example 7

Substrate Layer:

The substrate layer was composed of a 2-stage asynchronous biaxially stretched polyethylene terephthalate (PET) film with a thickness of 3 μm, an acid-modified polyolefin layer with a thickness of 2 μm and a 2-stage asynchronous biaxially stretched nylon film with a thickness of 20 μm, amounting to a total thickness of 25 μm.

Aluminum Alloy Foil Layer:

A 3-layer composite aluminum alloy foil of a first Mg—Al alloy foil layer, a 8021 Al foil layer, and a second Mg—Al alloy foil layer (in a thickness ratio of 2:6:2) with a total thickness of 40 μm was used. Each of the first and second Mg—Al alloy foil layers contained 1.8% of Mg, 1.4% of Fe, 0.1% of Si and 0.02% of Sb by mass percentage, and after annealing, the precipitation ratio of Mg to Al on the surface of the aluminum alloy foil layer was 3.5.

A solution-type mixture formed of an anhydrous maleic anhydride-modified polypropylene solution with a weight-average molecular weight of 60,000, a melting point of 75° C. and an acid value of 5 mg KOH/g, and an epoxy resin solution in a solid ratio of 10:1 was uniformly applied to a surface of one of the first and second Mg—Al alloy foil layers in the semi-finished product, and then dried to form the second bonding layer 7.

A surface of a 40 μm of CPP film (the same as that in Example 1) being the hot-melt connecting layer 8 was subjected to a corona treatment, and then the surface was heat-compounded with the second bonding layer 7 at 100° C., followed by aging at 40° C. for 7 days. Thus, a composite-finished product comprising the substrate layer (25 μm), the first bonding layer (3 μm), the aluminum alloy foil layer (40 μm), the second bonding layer (3 μm), and the hot-melt connecting layer (40 μm) was formed.

Meanwhile, the surface of the substrate layer was coated with the same amount of the Slip agent as in Example 1.