Composite polymer film, method of manufacture thereof, metallized composite polymer film and use

Abstract

The present application relates to a composite polymer film, its manufacturing method, metallized composite polymer film, and use. The composite polymer film of the present application includes a surface layer 1, a surface layer 2, and a core layer located between the surface layers 1 and 2. In mass %, the raw materials for the core layer include 98% to 99.8% polyester material, 0.1% to 1% inorganic nanomaterial, and 0.1% to 1% antioxidant, and the raw materials for the surface layers 1 and 2 each independently include 88% to 98.8% polyester material, 1% to 10% nanooxide, and 0.2% to 2% additive.

Description

[Technical Field]

[0001] This application relates to the technical field of batteries, and in particular to composite polymer films, methods for their manufacture, metallized composite polymer films and uses. [Background technology]

[0002] Metallized polymer films are widely used in fields such as electronics, packaging, and printing due to their excellent conductivity, barrier properties, flexibility, and light weight. Metallized polymer film products include composite current collectors, thin film electrodes, aluminum-plated packaging films, and printed thin films. Composite current collectors are typically manufactured by depositing a layer of metal material onto a thin polymer film using physical vapor deposition, resulting in a composite current collector with a surface-metallized thin film that has a certain degree of conductivity. Compared to conventional current collectors, polymer-based composite current collectors are lower in cost, lighter in weight, and have better internal insulation properties. Therefore, when used in batteries, these composite current collectors can reduce battery costs and improve the energy density and safety of the battery. However, conventional polyester films suffer from poor surface adhesion, low mechanical strength, and poor heat resistance. Furthermore, when polyester films are combined with metal materials, poor adhesion results in low adhesive strength between the two. Summary of the Invention [Problem to be solved by the invention]

[0003] According to various embodiments of the present application, composite polymer films, methods for their manufacture, metallized composite polymer films, and uses are provided. [Means for solving the problem]

[0004] The present application provides the following technical solutions.

[0005] The present application provides a composite polymer film comprising a surface layer 1, a surface layer 2, and a core layer located between the surface layer 1 and the surface layer 2, A composite polymer film is provided in which the raw materials for the core layer include, in mass %, 98% to 99.8% polyester material, 0.1% to 1% inorganic nanomaterial, and 0.1% to 1% antioxidant, and the raw materials for the surface layer 1 and the surface layer 2 each independently include 88% to 98.8% polyester material, 1% to 10% nanooxide, and 0.2% to 2% additive.

[0006] In some embodiments, the nanooxide comprises one or more of aluminum oxide, silica, titanium dioxide, zinc oxide, copper oxide, magnesium oxide, iron trioxide, iron tetroxide, zirconium dioxide, and tin dioxide.

[0007] In some embodiments, the inorganic nanomaterial comprises one or more of nanooxides, graphene, graphene oxide, carbon nanotubes, and carbon nanofibers.

[0008] In some embodiments, the polyester material comprises one or more of polyethylene terephthalate (PET), polyethylene-2,6-naphthalenedicarboxylate (PEN), polybutylene terephthalate (PBT), polycyclohexane 1,4-dimethylene terephthalate (PCT), polyethylene terephthalate-1,4-cyclohexanedimethylene terephthalate (PETG), polypropylene-2,6-naphthalenedicarboxylate (PTN), polytrimethylene terephthalate (PTT), polybutylene-2,6-naphthalenedicarboxylate (PBN), polybutylene-2,5-furanoate, polybutylene adipate terephthalate (PBAT), polyarylate (PAR), and derivatives thereof.

[0009] In some embodiments, the additives include antioxidants and lubricants. Preferably, the antioxidant comprises one or more of a phosphonate ester and a bisphenol A phosphite; Preferably, the lubricant comprises one or more of calcium carbonate, talc powder, kaolin, diatomaceous earth, siloxane, clay, mica, aluminum silicate, potassium phosphate, barium sulfate, acrylic esters.

[0010] In some embodiments, the composite polymer film has a thickness of 1 to 50 μm; Preferably, the percentages of the thickness of the core layer, surface layer 1, and surface layer 2 relative to the thickness of the composite polymer film are 70% to 90%, 5% to 15%, and 5% to 15%, respectively, and the thicknesses of surface layer 1 and surface layer 2 are equal.

[0011] The present application provides a method for producing the above-mentioned composite polymer film, Step S1 of manufacturing polyester chips A, B, and C, respectively, wherein, in mass%, the polyester chips A and C are each independently manufactured from 88% to 98.8% polyester material, 1% to 10% nano-oxide, and 0.2% to 2% additive, and the polyester chip B is manufactured from 98% to 99.8% polyester material, 0.1% to 1% inorganic nano-material, and 0.1% to 1% antioxidant; Step S2: melt-extrusion of the polyester chips A, B, and C to obtain a molten polyester material having a core layer, a surface layer 1, and a surface layer 2, wherein the core layer is located between the surface layer 1 and the surface layer 2; Step S3: subjecting the molten polyester material to molding and heat treatment in sequence; Further provided is a method for making a composite polymer film comprising:

[0012] In some embodiments, the heat treatment process of step S3 includes: A first stage in which the heat treatment temperature is 130 to 160°C and the heat treatment time is 0.5 to 2 minutes; A second stage in which the heat treatment temperature is 160 to 220°C and the heat treatment time is 0.5 to 5 minutes; A third stage in which the heat treatment temperature is 130 to 160°C and the heat treatment time is 0.5 to 2 minutes.

[0013] The present application provides a metallized composite polymer film comprising a composite polymer film that is the composite polymer film described above or a composite polymer film manufactured by the manufacturing method described above, and a metal conductive layer provided on at least one surface of the composite polymer film, Preferably, the metallized composite polymer film further provides that the material of the metal conductive layer comprises one or more of copper, copper alloy, aluminum, aluminum alloy, nickel, nickel alloy, titanium and silver.

[0014] In some embodiments, the metal conductive layer has a thickness of 20 to 2000 nm.

[0015] The present application further includes a composite current collector comprising the metallized composite polymer film described above.

[0016] In some embodiments, the composite current collector further comprises a protective layer located on the metal conductive layer of the metallized composite polymer film.

[0017] In some embodiments, the protective layer comprises one or more of nickel, chromium, a nickel-based alloy, a copper-based alloy, copper oxide, aluminum oxide, nickel oxide, chromium oxide, cobalt oxide, graphite, carbon black, acetylene black, ketjen black, carbon nano quantum dots, carbon nanotubes, carbon nanofibers, and graphene.

[0018] In some embodiments, the protective layer has a thickness of 100 to 150 nm.

[0019] Furthermore, the present application further provides an electrode piece including the above composite current collector.

[0020] Furthermore, the present application further provides a battery including the electrode piece.

[0021] Furthermore, the present application further provides an electronic device including the battery.

[0022] The details of one or more embodiments of the application are set forth in the description below. Other features, objects, and advantages of the application will become apparent from the description and claims. DETAILED DESCRIPTION OF THE INVENTION

[0023] The technical solution of the present application will be explained clearly and completely below with reference to specific examples. It is clear that the described examples are only some of the examples of the present application, and do not include all of the examples. All other examples that can be obtained by those skilled in the art based on the examples of the present application without paying creative labor fall within the scope of protection of the present application.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. The terms used herein are only for describing specific examples and are not intended to limit the scope of the present application. The term "one or more" as used herein includes any and all combinations of one or more associated items.

[0025] In this application, unless otherwise specified, any numerical range within the range is considered continuous and inclusive of the minimum and maximum values ​​within the range, as well as each value between such minimum and maximum values. Furthermore, when a range refers to integers, it also includes each integer between the minimum and maximum values ​​within the range. Furthermore, when multiple ranges are provided to describe a feature or characteristic, the ranges can be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges contained therein.

[0026] According to one embodiment of the present application, there is provided a composite polymer film including a surface layer 1, a surface layer 2, and a core layer located between the surface layer 1 and the surface layer 2, A composite polymer film is provided in which the raw materials for the core layer include, in mass %, 98% to 99.8% polyester material, 0.1% to 1% inorganic nanomaterial, and 0.1% to 1% antioxidant, and the raw materials for the surface layer 1 and the surface layer 2 each independently include 88% to 98.8% polyester material, 1% to 10% nanooxide, and 0.2% to 2% additive.

[0027] The surface polarity of polyester film is weak (35 mN / m), resulting in poor adhesion to metal materials. The tensile strength of polyester film is generally less than 250 MPa. Therefore, in a PVD (physical vapor deposition) system, the pressure of the winding system, the impact of metal atoms, and the rise in the surface temperature of the polyester film make the polyester film prone to breakage. Furthermore, polyester film has poor heat resistance and is prone to shrinkage due to the impact and deposition of high-temperature metal atoms, resulting in product defects and poor heat resistance of the composite current collector. When the composite current collector is applied to a battery, the associated coating and composite molding processes place high demands on the tensile strength of the polyester film.

[0028] In light of this, the present application provides a composite polymer film that improves the mechanical properties and heat resistance of the core layer through intermolecular forces between the inorganic nanomaterial and polyester material, and that segregates nanooxides in surface layers 1 and 2 to the surfaces of surface layers 1 and 2 during film formation and cooling, thereby improving the surface polarity and heat resistance of both layers. Therefore, the composite polymer film of the present application has the advantages of good surface adhesion, high mechanical strength, good processability, and good heat resistance. When a metallized composite polymer film is produced using this composite polymer film as a base film, the bonding strength between the composite polymer film and the surface metal conductive layer is also significantly improved. The content of the inorganic nanomaterial in the core layer of the composite polymer film of the present application and the content of the nanooxide in surface layers 1 and 2 must be neither too low nor too high. If the content of the inorganic nanomaterial and the nanooxide is too low, the improvement in performance of the composite polymer film is not significant, and if the content is too high, film formation defects are likely to occur.

[0029] In some embodiments, the nanooxide comprises one or more of aluminum oxide, silica, titanium dioxide, zinc oxide, copper oxide, magnesium oxide, ferric oxide, ferric tetroxide, zirconium dioxide, and tin dioxide.

[0030] In some embodiments, the shape of the nanooxide comprises one or more of spherical, linear, and tubular.

[0031] In some embodiments, the spherical nanooxides have a diameter of 5-80 nm, the linear nanooxides have a diameter of 3-30 nm and a length of 0.1-1 μm, and the tubular nanooxides have a diameter of 5-50 nm and a length of 0.1-1 μm.

[0032] In some embodiments, the graphene flakes have a diameter of 0.2 to 2 μm, a thickness of 0.8 to 0.9 nm, and a single-layer ratio of 60 to 80%. The graphene oxide flakes have a diameter of 0.2 to 2 μm and a thickness of 0.8 to 1.2 nm. The carbon nanotubes are single-walled carbon nanotubes with a diameter of 4 to 5 nm and a length of 0.2 nm to 2 μm. The carbon nanofibers have a diameter of 20 to 80 nm and a length of 0.2 to 2 μm.

[0033] In addition, the present application requires that the size of the nanooxides in surface layers 1 and 2 be limited; if the size of the nanooxides in surface layers 1 and 2 is too small, it is detrimental to improving the performance of the composite polymer film, and if the size is too large, they are difficult to segregate on the surface of surface layers 1 and 2, which limits the improvement in the bonding strength between the composite polymer film and the metal conductive layer and makes it more likely to cause film formation defects.

[0034] It should be understood that the nanooxide includes any one of aluminum oxide, silica, titanium dioxide, zinc oxide, copper oxide, magnesium oxide, iron trioxide, iron tetraoxide, zirconium dioxide, and tin dioxide, or a mixture of two or more of aluminum oxide, silica, titanium dioxide, zinc oxide, copper oxide, magnesium oxide, iron trioxide, iron tetraoxide, zirconium dioxide, and tin dioxide in any ratio.

[0035] In some embodiments, the inorganic nanomaterial comprises one or more of nanooxides, graphene, graphene oxide, carbon nanotubes, and carbon nanofibers.

[0036] It should be understood that the inorganic nanomaterial may include any one of nanooxides, graphene, graphene oxide, carbon nanotubes, and carbon nanofibers, or a mixture of two or more of nanooxides, graphene, graphene oxide, carbon nanotubes, and carbon nanofibers in any ratio.

[0037] In some embodiments, the polyester material comprises one or more of polyethylene terephthalate (PET), polyethylene-2,6-naphthalenedicarboxylate (PEN), polybutylene terephthalate (PBT), polycyclohexane 1,4-dimethylene terephthalate (PCT), polyethylene terephthalate-1,4-cyclohexanedimethylene terephthalate dimethylene terephthalate (PETG), polypropylene-2,6-naphthalenedicarboxylate (PTN), polytrimethylene terephthalate (PTT), polybutylene-2,6-naphthalenedicarboxylate (PBN), polybutylene-2,5-furanoate, polybutylene adipate terephthalate (PBAT), polyarylate (PAR), and derivatives thereof.

[0038] It should be understood that the polyester material includes any one of polyethylene terephthalate (PET), polyethylene-2,6-naphthalenedicarboxylate (PEN), polybutylene terephthalate (PBT), polycyclohexane 1,4-dimethylene terephthalate (PCT), polyethylene terephthalate-1,4-cyclohexanedimethylene terephthalate dimethylene terephthalate (PETG), polypropylene-2,6-naphthalenedicarboxylate (PTN), polytrimethylene terephthalate (PTT), polybutylene-2,6-naphthalenedicarboxylate (PBN), polybutylene-2,5-furanoate, polybutylene adipate terephthalate (PBAT), polyarylate (PAR) and derivatives thereof; or The polyester material includes polyethylene terephthalate (PET), polyethylene-2,6-naphthalenedicarboxylate (PEN), polybutylene terephthalate (PBT), polycyclohexane 1,4-dimethylene terephthalate (PCT), polyethylene terephthalate-1,4-cyclohexanedimethylene terephthalate dimethylene terephthalate (PETG), polypropylene-2,6-naphthalenedicarboxylate (PTN), polytrimethylene terephthalate (PTT), polybutylene-2,6-naphthalenedicarboxylate (PBN), polybutylene-2,5-furanoate, polybutylene adipate terephthalate (PBAT), polyarylate (PAR), and a mixture of two or more of these derivatives formed in any ratio.

[0039] In some embodiments, the additives include antioxidants and lubricants; Preferably, the antioxidant comprises one or more of a phosphonate ester and a bisphenol A phosphite; Preferably, the lubricant comprises one or more of calcium carbonate, talc powder, kaolin, diatomaceous earth, siloxane, clay, mica, aluminum silicate, potassium phosphate, barium sulfate, acrylic esters.

[0040] It should be understood that the antioxidant may comprise a phosphonate ester or a bisphenol A phosphite, or the antioxidant may comprise a mixture of a phosphonate ester and a bisphenol A phosphite in any ratio.

[0041] It should be understood that the lubricant may include any one of calcium carbonate, talc powder, kaolin, diatomaceous earth, siloxane, clay, mica, aluminum silicate, potassium phosphate, barium sulfate, and acrylic ester, or a mixture of two or more of calcium carbonate, talc powder, kaolin, diatomaceous earth, siloxane, clay, mica, aluminum silicate, potassium phosphate, barium sulfate, and acrylic ester in any ratio.

[0042] In some embodiments, the thickness of the composite polymer film is 1 to 50 μm; Preferably, the percentages of the thickness of the core layer, surface layer 1, and surface layer 2 relative to the thickness of the composite polymer film are 5% to 15%, 70% to 90%, and 70% to 90%, respectively, and the thicknesses of surface layer 1 and surface layer 2 are equal.

[0043] In some embodiments, the thickness of the composite polymer film is between 2 and 20 μm.

[0044] It should be understood that the thickness of the composite polymer film may be any value between 1 and 50 μm or 2 and 20 μm, such as 1 μm, 2 μm, 4 μm, 8 μm, 12 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 55 μm, etc. The percentage of the thickness of the core layer, surface layer 1, and surface layer 2 to the thickness of the composite polymer film may be any value between 70% and 90%, 5% and 15%, or 5% and 15%, respectively, and the ratio of the thickness of the core layer, surface layer 1, and surface layer 2 to the thickness of the composite polymer film may be, for example, 90%, 5%, 5%, 84%, 8%, 8%, 80%, 10%, 10%, 76%, 12%, 12%, or 70%, 15%, 15%.

[0045] The present application provides a method for producing the above-mentioned composite polymer film, Step S1 of producing polyester chips A, B, and C, respectively, in which, by mass%, polyester chips A and C are independently produced from 88% to 98.8% polyester material, 1% to 10% nano-oxide, and 0.2% to 2% additive, and polyester chip B is produced from 98% to 99.8% polyester material, 0.1% to 1% inorganic nano-material, and 0.1% to 1% antioxidant; Step S2: melt-extrusion of polyester chips A, polyester chips B, and polyester chips C to obtain a molten polyester material having a core layer, a surface layer 1, and a surface layer 2, the core layer being located between the surface layer 1 and the surface layer 2; Step S3: subjecting the molten polyester material to molding and heat treatment in sequence; Further provided is a method for making a composite polymer film comprising:

[0046] The polyester chips A form the surface layer 1, the polyester chips B form the core layer, and the polyester chips C form the surface layer 2.

[0047] During the manufacturing process of the composite polymer film of the present application, the nano-oxide segregates on the surface of the composite polymer film, forming an organic-inorganic hybrid layer mainly composed of nano-oxide, and utilizing the good adhesion between the nano-oxide and the metal material, the adhesion strength between the composite polymer film and the metal conductive layer is improved.

[0048] In some embodiments, the molding process of step S3 includes the following steps:

[0049] (1) Slab: In step S2, the molten polyester material is cast onto a slab roll, and after passing through the slab roll and water cooling treatment, a slab is obtained.

[0050] (2) Longitudinal stretching: The above-mentioned cast piece is preheated at 70 to 100°C and then stretched in the longitudinal direction to obtain a film piece. Then, the piece is heat-set at 165 to 180°C and cooled at 30 to 50°C. Here, the longitudinal stretching ratio is (3 to 5):1, and the longitudinal stretching temperature is 80 to 120°C.

[0051] (3) Transverse stretching: The film piece is preheated at 80 to 120°C and then stretched in the transverse direction, followed by heat setting at 150 to 250°C and cooling at 80 to 150°C. Here, the transverse stretching ratio is (3 to 5):1, and the transverse stretching temperature is 90 to 140°C.

[0052] In some embodiments, the heat treatment process of step S3 includes: A first stage in which the heat treatment temperature is 130 to 160°C and the heat treatment time is 0.5 to 2 minutes; A second stage in which the heat treatment temperature is 160 to 220°C and the heat treatment time is 0.5 to 5 minutes; A third stage in which the heat treatment temperature is 130 to 160°C and the heat treatment time is 0.5 to 2 minutes; Includes:

[0053] The present application provides a metallized composite polymer film, comprising a composite polymer film that is the composite polymer film described above or a composite polymer film manufactured by the manufacturing method described above, and a metal conductive layer provided on at least one surface of the composite polymer film, Preferably, the metallized composite polymer film further provides that the material of the metal conductive layer comprises one or more of copper, copper alloy, aluminum, aluminum alloy, nickel, nickel alloy, titanium and silver.

[0054] It should be understood that the metal conductive layer may be made of one or more of copper, copper alloy, aluminum, aluminum alloy, nickel, nickel alloy, titanium, and silver.

[0055] In some embodiments, the thickness of the metal conductive layer is 20 to 2000 nm.

[0056] In some embodiments, the thickness of the metal conductive layer is 30 to 1000 nm.

[0057] It should be understood that the thickness of the metal conductive layer may be any value between 20 and 2000 nm or between 30 and 1000 nm, for example, the thickness of the metal conductive layer may be 20 nm, 25 nm, 30 nm, 50 nm, 150 nm, 250 nm, 350 nm, 450 nm, 550 nm, 650 nm, 750 nm, 850 nm, 950 nm, 1000 nm, 1050 nm, 1150 nm, 1250 nm, 1350 nm, 1450 nm, 1550 nm, 1650 nm, 1750 nm, 1850 nm, 1950 nm, 2000 nm.

[0058] In some embodiments, the method for producing the metal conductive layer comprises one or more of a physical vapor deposition method, a plating method, and an electroless plating method; Preferably, the physical vapor deposition method includes one or more of a resistance heating vacuum evaporation method, an electron beam heating vacuum evaporation method, a laser heating vacuum evaporation method, and a magnetron sputtering method.

[0059] In some embodiments, the thickness of the composite polymer film in the metallized composite polymer film is 1 to 20 μm.

[0060] It should be understood that the thickness of the composite polymer film within the metallized composite polymer film can be any value between 1 and 20 μm, for example, the thickness of the composite polymer film within the metallized composite polymer film can be 1 μm, 3 μm, 5 μm, 7 μm, 9 μm, 11 μm, 13 μm, 15 μm, 17 μm, 19 μm, 20 μm.

[0061] The present application further provides a composite current collector comprising the metallized composite polymer film described above.

[0062] In some embodiments, the composite current collector further comprises a protective layer located on the metal conductive layer of the metallized composite polymer film.

[0063] In some embodiments, the protective layer comprises one or more of nickel, chromium, a nickel-based alloy, a copper-based alloy, copper oxide, aluminum oxide, nickel oxide, chromium oxide, cobalt oxide, graphite, carbon black, acetylene black, ketjen black, carbon nano quantum dots, carbon nanotubes, carbon nanofibers, and graphene.

[0064] In some embodiments, the thickness of the protective layer is 10 to 150 nm.

[0065] In some embodiments, the thickness of the protective layer is 20 to 100 nm.

[0066] It should be understood that the thickness of the protective layer may be any value between 10 and 150 nm or 20 and 100 nm, for example, the thickness of the protective layer may be 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 45 nm, 55 nm, 65 nm, 75 nm, 85 nm, 95 nm, 100 nm, 105 nm, 115 nm, 125 nm, 135 nm, 145 nm, 150 nm.

[0067] In some embodiments, the method for producing the protective layer includes one or more of physical vapor deposition, in-situ casting, and coating.

[0068] In some embodiments, the physical vapor deposition method includes one or more of a vacuum evaporation method and a magnetron sputtering method.

[0069] In some embodiments, the in-situ forming method includes forming a metal oxide dulling layer in-situ on the surface of the metal conductive layer.

[0070] In some embodiments, the coating method includes one or more of a die coating method, a knife coating method, and a squeeze coating method.

[0071] In some embodiments, the protective layer is two-layered, the materials of the two protective layers may be the same or different, and the thicknesses of the two protective layers may be equal or unequal.

[0072] Furthermore, the present application further provides an electrode piece including the above composite current collector.

[0073] It should be understood that the electrode strips of the present application can be obtained by mixing a positive electrode active material / a negative electrode active material, a conductive agent, a binder, and a solvent to form a slurry, and then applying the slurry to the composite current collector of the present application using a manufacturing method for electrode strips that is familiar to those skilled in the art. Depending on the active material, the electrode strips can be divided into positive electrode strips and negative electrode strips. The manufacturing method for the electrode strips is familiar to those skilled in the art, and is not particularly limited in the present application.

[0074] Furthermore, the present application further provides a battery including the electrode piece.

[0075] It should be understood that the battery according to the present application may be a lithium ion secondary battery, a lithium ion polymer secondary battery, a lithium metal secondary battery, a lithium polymer secondary battery, or the like, and the battery is not particularly limited in the present application.

[0076] Furthermore, the present application further provides an electronic device including the battery.

[0077] It should be understood that the electronic device of the present application is not particularly limited and may be, for example, an electric vehicle, a smart home appliance, a digital camera, a mobile phone, a computer, etc., and the battery of the present application is used in the electronic device as a power source or energy storage unit.

[0078] The present invention will be described in more detail below with reference to specific examples and comparative examples.

[0079] Example 1 The polyester material of the core layer, surface layer 1 and surface layer 2 is a polyethylene terephthalate (PET) resin having an intrinsic viscosity of 0.731 dL / g and a molecular weight distribution of 2.2.

[0080] The inorganic nanomaterial of the core layer was spherical nano-aluminum oxide (average diameter 40 nm), and the additive of the core layer was antioxidant 1222.

[0081] The nano-oxides in the surface layers 1 and 2 are both spherical nano-silica (average diameter 30 nm), the antioxidant is antioxidant 1222, and the lubricant is calcium carbonate.

[0082] The method for producing a composite polymer film includes the following steps.

[0083] S1: Production of polyester chips A, B, and C

[0084] In terms of mass%, polyester chips A and polyester chips C were each independently produced by sequentially heating, melting, mixing, extruding, and shaping / slicing 98% PET resin, 1% nanosilica, 0.5% antioxidant 1222, and 0.5% calcium carbonate. Polyester chips B was produced by sequentially heating, melting, mixing, extruding, and shaping / slicing 99.4% PET resin, 0.1% nanoaluminum oxide, and 0.5% antioxidant 1222. The resulting polyester chips A, B, and C were sent to a crystallizer and treated at 140°C for 40 minutes. The crystallized polyester chips A, B, and C were then sent to a dryer and dried at 150°C for 160 minutes.

[0085] S2: Manufacturing of molten polyester material

[0086] The polyester chips A, polyester chips B, and polyester chips C obtained in step S1 were fed into different twin-screw extruders and melt-processed at 280°C. The molten liquid was extruded through a die using a metering pump to obtain a molten polyester material having a core layer, surface layer 1, and surface layer 2, with the core layer being located between surface layer 1 and surface layer 2, and the extrusion ratios of the core layer, surface layer 1, and surface layer 2 being 80%, 10%, and 10% (mass ratio), respectively, with polyester chips A forming surface layer 1, polyester chips B forming the core layer, and polyester chips C forming surface layer 2.

[0087] S3: Fabrication of composite polymer films

[0088] S3.1: Forming process

[0089] (1) Slab: In step S2, the molten polyester material was cast onto a slab roll, and after passing through the slab roll and water cooling treatment, a slab was obtained.

[0090] (2) Longitudinal stretching: The above-mentioned cast piece was preheated at 90°C and then longitudinally stretched to obtain a film piece. After heat setting at 170°C, it was cooled at 40°C. Here, the longitudinal stretching ratio was 4:1, and the longitudinal stretching temperature was 110°C.

[0091] (3) Transverse stretching: The film pieces were preheated at 90°C, stretched in the transverse direction, heat-set at 170°C, and then cooled at 110°C. The transverse stretching ratio was 4:1, and the transverse stretching temperature was 120°C.

[0092] S3.2: Heat treatment

[0093] The film pieces obtained in S3.1 were heat-treated to prepare composite polymer films, the thickness of which was 6 μm, and the heat-treatment process included the following steps:

[0094] First stage: the heat treatment temperature is 140°C, and the heat treatment time is 0.5 min.

[0095] Second stage: the heat treatment temperature is 160°C, and the heat treatment time is 0.5 min.

[0096] Third step: the heat treatment temperature is 140°C, and the heat treatment time is 0.5 min.

[0097] A composite current collector is prepared according to the following method.

[0098] (1) Manufacturing of metal conductive layers

[0099] The fabricated composite polymer film was placed in a vacuum deposition chamber, and high-purity aluminum wire (purity exceeding 99.99%) in the metal evaporation chamber was melted and evaporated under conditions of 1300-2000°C. The evaporated metal atoms passed through the cooling system in the vacuum deposition chamber and were deposited on both surfaces of the composite polymer film, forming a 1 μm-thick aluminum metal conductive layer.

[0100] (2) Manufacturing the protective layer

[0101] 1 g of carbon nanotubes was uniformly dispersed in 999 g of N-methylpyrrolidone (NMP) using ultrasonic dispersion to prepare a coating solution with a solid content of 0.1 wt %. The coating solution was then uniformly applied to the surface of the metal conductive layer using a die coating process, where the coating amount was limited to 90 μm, and finally dried at 100°C.

[0102] Example 2 In step S1, the polyester chip A and polyester chip C layers were each independently manufactured from 96% PET resin, 3% nanosilica, 0.5% antioxidant 1222, and 0.5% calcium carbonate, in mass %, which was essentially the same as Example 1.

[0103] Example 3 In step S1, the polyester chip A and polyester chip C layers were each independently manufactured from 94% PET resin, 5% nanosilica, 0.5% antioxidant 1222, and 0.5% calcium carbonate, in mass %, which was essentially the same as Example 1.

[0104] Example 4 In step S1, the polyester chip A and polyester chip C layers were each independently manufactured from 92% PET resin, 7% nanosilica, 0.5% antioxidant 1222, and 0.5% calcium carbonate, in mass %, which was essentially the same as Example 1.

[0105] Example 5 In step S1, the polyester chip A and polyester chip C layers were each independently manufactured from 90% PET resin, 9% nanosilica, 0.5% antioxidant 1222, and 0.5% calcium carbonate, in mass %, which was essentially the same as Example 1.

[0106] Example 6 In step S1, the polyester chip A and polyester chip C layers were each independently manufactured from 89% PET resin, 10% nanosilica, 0.5% antioxidant 1222, and 0.5% calcium carbonate, in mass %, which was essentially the same as Example 1.

[0107] Example 7 The nano-oxides in the surface layer 1 and the surface layer 2 were both tubular nano-silica (diameter 25 nm, length 0.4 μm), but this was basically the same as in Example 4.

[0108] Example 8 The nano-oxides in the surface layer 1 and the surface layer 2 were both linear nano-silica (diameter 10 nm, length 0.5 μm), but this was basically the same as in Example 4.

[0109] Example 9 The nano-oxides in the surface layer 1 and the surface layer 2 were both linear nano-aluminum oxide (diameter 10 nm, length 0.5 μm), but this was basically the same as in Example 8.

[0110] Example 10 The nano-oxides in the surface layer 1 and the surface layer 2 were both linear nano-titanium dioxide (diameter 10 nm, length 0.5 μm), but this was basically the same as in Example 8.

[0111] Example 11 In step S1, the polyester chip B layer was made of 99.2% PET resin, 0.3% nano aluminum oxide, and 0.5% antioxidant 1222, in mass %, which was basically the same as in Example 8.

[0112] Example 12 In step S1, the polyester chip B layer was made of 99.0% PET resin, 0.5% nano aluminum oxide, and 0.5% antioxidant 1222, in mass %, which was basically the same as in Example 8.

[0113] Example 13 In step S1, the polyester chip B layer was made of 98.8% PET resin, 0.7% nano aluminum oxide, and 0.5% antioxidant 1222, in mass %, which was basically the same as in Example 8.

[0114] Example 14 In step S1, the polyester chip B layer was made of 98.6% PET resin, 0.9% nano aluminum oxide, and 0.5% antioxidant 1222, in mass %, which was basically the same as in Example 8.

[0115] Example 15 In step S1, the polyester chip B layer was made of 98.5% PET resin, 1.0% nano aluminum oxide, and 0.5% antioxidant 1222, in mass %, which was basically the same as in Example 8.

[0116] Example 16 This is basically the same as Example 12, except that the inorganic nanomaterial of the core layer is tubular nano-aluminum oxide (diameter 25 nm, length 0.4 μm).

[0117] Example 17 This is basically the same as Example 12, except that the inorganic nanomaterial of the core layer is linear nano-aluminum oxide (diameter 10 nm, length 0.5 μm).

[0118] Example 18 This is basically the same as Example 17, except that the inorganic nanomaterial of the core layer is a single-walled carbon nanotube (diameter 5 nm, length 0.2 μm).

[0119] Example 19 This is basically the same as Example 17, except that the inorganic nanomaterial of the core layer is graphene (flake diameter 0.2 μm, thickness 0.8 nm, single layer ratio 80%).

[0120] Example 20 The procedure is basically the same as in Example 19, except that the heat treatment time in the second stage of the heat treatment process in step S3.2 is 1 minute.

[0121] Example 21 This is basically the same as Example 19, except that in the second stage of the heat treatment process in step S3.2, the heat treatment time is 2 minutes.

[0122] Example 22 This is basically the same as Example 19, except that the heat treatment time in the second stage of the heat treatment process in step S3.2 is 3 minutes.

[0123] Example 23 The procedure is basically the same as in Example 19, except that the heat treatment time in the second stage of the heat treatment process in step S3.2 is 5 minutes.

[0124] Example 24 This is basically the same as Example 21, except that the heat treatment temperature in the second stage of the heat treatment process in step S3.2 is 180°C.

[0125] Example 25 This is basically the same as Example 21, except that the heat treatment temperature in the second stage of the heat treatment process in step S3.2 is 200°C.

[0126] Example 26 This is basically the same as Example 21, except that the heat treatment temperature in the second stage of the heat treatment process in step S3.2 is 220°C.

[0127] Example 27 In step S1, polyester chip A and polyester chip C were each independently produced from 98.8% PET resin, 1% nanosilica, 0.1% antioxidant 1222, and 0.1% calcium carbonate, in mass %, which was essentially the same as Example 1.

[0128] Example 28 In step S1, polyester chip A and polyester chip C were each independently produced from 88% PET resin, 10% nanosilica, 1% antioxidant 1222, and 1% calcium carbonate, in mass %, which was essentially the same as Example 1.

[0129] Example 29 In step S1, polyester chip B was prepared from 99.8% PET resin, 0.1% nano-aluminum oxide, and 0.1% antioxidant 1222, which was essentially the same as Example 8.

[0130] Example 30 In step S1, polyester chip B was prepared from 98% PET resin, 1% nano-aluminum oxide, and 1% antioxidant 1222, in mass %, which was essentially the same as in Example 8.

[0131] Comparative Example 1 In step S1, the polyester chip A and polyester chip C layers were each independently manufactured from 99% PET resin, 0.5% antioxidant 1222, and 0.5% calcium carbonate, in mass %, and polyester chip B was manufactured from 99.5% PET resin and 0.5% antioxidant 1222, which was basically the same as Example 1.

[0132] Comparative Example 2 In step S1, the polyester chip A and polyester chip C layers were each independently manufactured from, by mass, 98.5% PET resin, 0.5% nanosilica, 0.5% antioxidant 1222, and 0.5% calcium carbonate, which was essentially the same as Example 1.

[0133] Comparative Example 3 In step S1, the polyester chip A and polyester chip C layers were each independently manufactured from 87% PET resin, 12% nanosilica, 0.5% antioxidant 1222, and 0.5% calcium carbonate, in terms of mass %, which was essentially the same as Example 1.

[0134] Comparative Example 4 In step S1, polyester chip B was prepared from 99.45% PET resin, 0.05% nano-aluminum oxide, and 0.5% antioxidant 1222, in mass %, which was essentially the same as in Example 8.

[0135] Comparative Example 5 In step S1, polyester chip B was prepared from 98% PET resin, 1.5% nano-aluminum oxide, and 0.5% antioxidant 1222, in terms of mass %, which was essentially the same as in Example 8.

[0136] Comparative Example 6 This is basically the same as Example 19, except that the heat treatment time in the second stage of the heat treatment process in step S3.2 is 0.1 min.

[0137] Comparative Example 7 This is basically the same as Example 19, except that the heat treatment time in the second stage of the heat treatment process in step S3.2 is 6 minutes.

[0138] Comparative Example 8 This is basically the same as Example 21, except that the heat treatment temperature in the second stage of the heat treatment process in step S3.2 is 155°C.

[0139] Comparative Example 9 This is basically the same as Example 21, except that the heat treatment temperature in the second stage of the heat treatment process in step S3.2 is 225°C.

[0140] Test Example 1: Performance Measurement of Composite Polymer Film and Composite Current Collector The fabricated composite polymer films and composite current collectors were subjected to measurements of tensile strength, elongation at break and thermal shrinkage with reference to Chinese national standards GB / T 1040.3-2006 and GB / T 10003-2008.

[0141] The adhesive strength between the composite polymer film and the metal conductive layer was measured. A layer of Permacel P-94 double-sided tape was attached to a 1 mm thick piece of aluminum foil. A composite current collector was then attached to the double-sided tape. A layer of ethylene-acrylic acid copolymer thin film (DuPont Nurcel 0903, 50 μm thick) was then coated on top of the composite current collector. The composite current collector was then hot-pressed at 1.3 × 105 N / m2 and 120 °C for 10 s, cooled to room temperature, and cut into 150 mm × 15 mm pieces. Finally, the ethylene-acrylic acid copolymer thin film of the sample piece was clamped to the upper jig of a tensile machine, and the remaining portion was clamped to the lower jig. After clamping, the two pieces were peeled at an angle of 180° at a rate of 100 mm / min. The peel strength, i.e., the adhesive strength between the composite polymer film and the metal conductive layer, was measured. The measurement results are shown in Tables 1 and 2.

[0142] [Table 1]

[0143] Note: MD represents the longitudinal direction of the composite polymer film, and TD represents the transverse direction of the composite polymer film. The direction in which the longer side of the composite polymer film is the longitudinal direction, and the direction in which the shorter side of the composite polymer film is the transverse direction; the two directions are perpendicular to each other. The thermal shrinkage is data measured after heating the composite polymer film at 150 °C for 30 min.

[0144] [Table 2]

[0145] Note: MD represents the longitudinal direction of the composite current collector, and TD represents the transverse direction of the composite current collector. The direction in which the side length of the composite current collector is longer is the longitudinal direction, and the direction in which the side length of the composite current collector is shorter is the transverse direction. The two directions are perpendicular to each other. The thermal shrinkage is data measured after heating the current collector at 150 °C for 30 min.

[0146] As can be seen from Tables 1-2, Examples 1-6 investigate the effect of varying the content of nanosilica in Surface Layer 1 and Surface Layer 2 on the performance of the composite polymer film. Examples 4, 7, and 8 investigate the effect of the shape of silica in Surface Layer 1 and Surface Layer 2 on the performance of the composite polymer film. Examples 8-10 investigate the effect of the type of nanooxide in Surface Layer 1 and Surface Layer 2 on the performance of the composite polymer film. Examples 8 and 11-15 investigate the effect of the content of nanoaluminum oxide in the core layer on the performance of the composite polymer film. Examples 12 and 16-17 investigate the effect of the shape of nanoaluminum oxide in the core layer on the performance of the composite polymer film. Examples 17-19 investigate the effect of the type of inorganic nanomaterial in the core layer on the performance of the composite polymer film. Examples 19 to 23 investigated the effect of the heat treatment time in the second stage of the heat treatment process on the performance of the composite polymer film, and found that by increasing the heat treatment time in the second stage, the crystallinity of the composite polymer film could be improved, thereby improving the tensile strength of the composite polymer film and reducing the heat shrinkage rate and elongation at break.

[0147] In Examples 21 and 24 to 25, the effect of the heat treatment temperature in the second stage of the heat treatment process on the performance of the composite polymer film was investigated, and it was found that by increasing the heat treatment temperature in the second stage, the crystallinity of the composite polymer film could be improved, thereby improving the tensile strength of the composite polymer film and reducing the heat shrinkage rate and breaking elongation.

[0148] Compared with Examples 1 to 6 and 27 to 28, the composite polymer films produced in Comparative Examples 1 and 2 had lower stretching strength in both MD and TD, and higher elongation at break and thermal shrinkage in both MD and TD. In addition, the composite polymer films produced in Comparative Examples 1 and 2 had lower adhesive strength with the metal conductive layer. Therefore, it has been found that if the amount of PET resin added in Surface Layer 1 and Surface Layer 2 of Comparative Examples 1 and 2 is too low or too high, it is detrimental to improving the surface adhesiveness, mechanical strength, and heat resistance of the composite polymer film.

[0149] Compared with Examples 1 to 6 and Examples 27 to 28, the composite polymer film and composite current collector produced in Comparative Example 3 were found to have good heat resistance performance because the thermal shrinkage rates were small in both MD and TD, but were found to have poor mechanical strength because the stretching strength in both MD and TD was clearly low.

[0150] The composite polymer films produced in Comparative Examples 4 to 5 and Examples 11 to 15 and Example 30 all had an adhesive strength of 4.5 N / cm with the metal conductive layer. However, compared to Examples 11 to 15 and Example 30, the composite polymer films and composite current collectors produced in Comparative Examples 4 to 5 had significantly lower stretching strength in both the MD and TD directions, indicating that the mechanical strength of the composite polymer films and composite current collectors produced in Comparative Examples 4 to 5 was poor.

[0151] The composite polymer films produced in Comparative Example 6 and Examples 19 to 23 all had an adhesive strength of 4.5 N / cm with the metal conductive layer. However, compared to Examples 19 to 23, the composite polymer film and composite current collector produced in Comparative Example 6 had relatively low stretching strength in both MD and TD, and relatively high elongation at break and thermal shrinkage. This indicates that the mechanical strength and heat resistance of the composite polymer film and composite current collector produced in Comparative Example 6 were inferior.

[0152] The composite polymer films produced in Comparative Examples 8 to 9 have the same adhesive strength with the metal conductive layer as those in Examples 21 and 24 to 26. However, the composite polymer films and composite current collectors produced in Comparative Examples 8 to 9 have relatively low stretching strength in both the MD and TD directions, and relatively high elongation at break and thermal shrinkage. This indicates that the mechanical strength of the composite polymer films and composite current collectors produced in Comparative Examples 8 to 9 is poor.

[0153] As can be seen from these results, the composite polymer film according to the present invention has significantly improved surface adhesion, mechanical strength and heat resistance.

[0154] The technical features of the above-described embodiments can be combined in any manner, and for the sake of brevity, not all possible combinations of the technical features in the above-described embodiments are described, but combinations of these technical features should be considered to fall within the scope described in this specification unless there is a contradiction.

[0155] The above examples are merely illustrative of some embodiments of the present application, and although the descriptions are more specific and detailed, they should not be understood as limiting the scope of the claims. Those skilled in the art may make minor modifications and improvements without departing from the spirit of the present application, and all such modifications and improvements should fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent is governed by the appended claims.

Claims

1. A composite polymer film comprising a surface layer 1, a surface layer 2, and a core layer located between the surface layer 1 and the surface layer 2, In mass %, the raw materials for the core layer include 98% to 99.8% polyester material, 0.1% to 1% inorganic nanomaterial, and 0.1% to 1% antioxidant, and the raw materials for the surface layer 1 and the surface layer 2 each independently include 88% to 98.8% polyester material, 1% to 10% nanooxide, and 0.2% to 2% additive; A composite polymer film characterized by:

2. The nanooxides include one or more of aluminum oxide, silica, titanium dioxide, zinc oxide, copper oxide, magnesium oxide, iron trioxide, iron tetroxide, zirconium dioxide, and tin dioxide; The composite polymer film of claim 1 .

3. The inorganic nanomaterials include one or more of nanooxides, graphene, graphene oxide, carbon nanotubes, and carbon nanofibers; 3. The composite polymer film according to claim 1, wherein the polymer film is a composite polymer film.

4. The polyester material comprises one or more of polyethylene terephthalate, polyethylene-2,6-naphthalenedicarboxylate, polybutylene terephthalate, polycyclohexane 1,4-dimethylene terephthalate, polyethylene terephthalate-1,4-cyclohexanedimethylene terephthalatedimethylene terephthalate, polypropylene-2,6-naphthalenedicarboxylate, polytrimethylene terephthalate, polybutylene-2,6-naphthalenedicarboxylate, polybutylene-2,5-furanoate, polybutylene adipate terephthalate, polyarylate, and derivatives thereof; The composite polymer film according to any one of claims 1 to 3.

5. The additives include antioxidants and lubricants; Preferably, the antioxidant comprises one or more of a phosphonate ester and a bisphenol A phosphite; Preferably, the lubricant comprises one or more of calcium carbonate, talc powder, kaolin, diatomaceous earth, siloxane, clay, mica, aluminum silicate, potassium phosphate, barium sulfate, and acrylic esters; The composite polymer film according to any one of claims 1 to 4.

6. The thickness of the composite polymer film is 1 to 50 μm. The composite polymer film according to any one of claims 1 to 5.

7. A method for producing the composite polymer film according to any one of claims 1 to 6, comprising: Step S1 of manufacturing polyester chips A, B, and C, respectively, wherein, in mass%, the polyester chips A and C are each independently manufactured from 88% to 98.8% polyester material, 1% to 10% nano-oxide, and 0.2% to 2% additive, and the polyester chips B are each independently manufactured from 98% to 99.8% polyester material, 0.1% to 1% inorganic nano-material, and 0.1% to 1% antioxidant; Step S2: melt-extruding the polyester chips A, B, and C to obtain a molten polyester material having a core layer, a surface layer 1, and a surface layer 2, wherein the core layer is located between the surface layer 1 and the surface layer 2; and step S3 of subjecting the molten polyester material to a molding process and a heat treatment in sequence. A method for producing a composite polymer film, comprising:

8. The heat treatment process in step S3 is a first stage in which the heat treatment temperature is 130 to 160°C and the heat treatment time is 0.5 to 2 minutes; a second stage in which the heat treatment temperature is 160 to 220°C and the heat treatment time is 0.5 to 5 minutes; A third step in which the heat treatment temperature is 130 to 160°C and the heat treatment time is 0.5 to 2 minutes; The method for producing a composite polymer film according to claim 7 .

9. A metallized composite polymer film comprising: a composite polymer film that is the composite polymer film according to any one of claims 1 to 6 or a composite polymer film manufactured by the manufacturing method according to any one of claims 7 to 8; and a metal conductive layer provided on at least one surface of the composite polymer film, Preferably, the material of the metal conductive layer comprises one or more of copper, copper alloy, aluminum, aluminum alloy, nickel, nickel alloy, titanium and silver; 1. A metallized composite polymer film comprising:

10. The thickness of the metal conductive layer is 20 to 2000 nm.

10. The metallized composite polymer film of claim 9.

11. A metallized composite polymer film according to any one of claims 9 to 10, A composite current collector characterized by:

12. a protective layer located on the metal conductive layer of the metallized composite polymer film; 12. The composite current collector of claim 11.

13. the protective layer comprises one or more of nickel, chromium, a nickel-based alloy, a copper-based alloy, copper oxide, aluminum oxide, nickel oxide, chromium oxide, cobalt oxide, graphite, carbon black, acetylene black, ketjen black, carbon nano quantum dots, carbon nanotubes, carbon nanofibers, and graphene; 13. The composite current collector of claim 12.

14. The thickness of the protective layer is 10 to 150 nm. The composite current collector according to any one of claims 12 to 13.

15. A composite current collector comprising the composite current collector according to any one of claims 11 to 14. An electrode piece characterized by:

16. The electrode strip according to claim 15, A battery characterized by:

17. 17. A battery comprising the battery of claim 16. An electronic device characterized by:

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