Film processing method and corresponding film

Abstract

The invention discloses a thin film processing method which comprises the following steps: S1, applying a chemical treatment agent to the surface of a thin film, and carrying out chemical micro-etching on the surface of the thin film; the mechanical property of the film is compensated while the surface of the film is subjected to chemical micro-etching; the mechanical properties include breaking strength and / or elongation. Through micro-etching the surface of the film, the surface performance of the film can be changed, and the surface adhesiveness is improved; compared with a corona treatment mode and the like, the micro-etching basically does not influence the mechanical strength of the thin film, and the micro-etching can improve the surface performance of the thin film and avoid the influence on the mechanical strength at the same time. The method provided by the invention corresponds to a production process, required equipment is simple, the cost is low, and the application range is wide; the obtained film has the advantages of improved adhesive force, guaranteed mechanical property and uniform performance; based on the thin film obtained by the processing method, the service life, safety and the like of corresponding downstream products, namely a composite current collector and a battery can be prolonged, and the corresponding products generally show excellent product quality.

Description

Technical Field

[0001] The present invention relates to the technical field of thin film processing, and more specifically, to a thin film processing method and a corresponding thin film. Background Art

[0002] Currently, for products obtained by laminating with a thin film as a substrate, when the surface adhesion of the thin film itself is low or the surface properties of the thin film and the structure of the layer to be laminated are quite different, the product has problems such as unstable lamination and easy detachment. Therefore, the prior art usually needs to improve the surface properties of such thin films, and the relatively common treatment method is corona treatment. Corona treatment at least uses high-frequency and high-voltage corona discharge on the surface of the thin film to generate low-temperature plasma, causing a free radical reaction on the surface of the thin film to crosslink the polymer, making the surface rough and increasing its wettability to polar solvents; and the plasma enters the surface of the thin film by electric shock and penetration to destroy its molecular structure, and oxidizes and polarizes the surface molecules of the thin film, etc.; ultimately enhancing the surface adhesion ability of the thin film, etc.

[0003] Although corona treatment can enhance the adhesion of the thin film, it will cause obvious mechanical property losses after treatment. This mechanical property loss will affect the quality of the corresponding product to a certain extent; when it is applied to the surface treatment of ultra-thin films, the impact on the corresponding product is more obvious. For example, for a composite current collector formed by laminating a thin film with a thickness of several micrometers and a metal foil layer; applying corona treatment to achieve the required surface adhesion performance in this field will significantly reduce the mechanical properties such as the elongation rate and breaking strength of the ultra-thin film substrate layer; thereby affecting the elongation rate, tensile strength, etc. of the composite current collector. For the composite current collector, such mechanical property strength is an important factor affecting the performance and quality of the composite current collector, directly affecting the product quality, stability, and safety of the composite current collector, etc. Therefore, there is an urgent need for a thin film processing method that can replace corona treatment to change the surface properties of the thin film while minimizing or avoiding the impact on mechanical properties. Summary of the Invention

[0004] The present invention aims to overcome at least one of the above-mentioned deficiencies of the prior art, and provides a thin film processing method and a corresponding thin film, which improve the surface of the thin film based on chemical micro-etching and avoid affecting the mechanical properties of the thin film.

[0005] The technical solution adopted by the present invention is a thin film processing method, including the steps: S1. Apply a chemical treatment agent to the surface of the thin film to perform chemical micro-etching on the surface of the thin film; and compensate for the mechanical properties of the thin film while chemically micro-etching the surface of the thin film; The mechanical properties include breaking strength and / or elongation rate.

[0006] The present application can change the surface properties of the film, including roughness, surface tension, etc., by micro-etching the surface of the film, and improve the surface adhesion; it is convenient to compound with other layer structures, especially with the metal layer, and maintain a stable composite state. At the same time, compared with the methods such as corona treatment, the micro-etching of the present application has less loss on the mechanical strength of the film. The micro-etching only acts on the surface micro-thickness, and does not penetrate and destroy the internal structure, which can make the film improve the surface properties while avoiding the obvious impact on the mechanical strength. Through this processing method, the corona treatment and other methods can be replaced to avoid the obvious mechanical property loss caused by changing the surface properties of the film in the corona treatment method. And the processing method is simple, only a certain amount of chemical treatment agent micro-etching can be achieved, and the application amount, action time, etc. can be configured to control the degree of micro-etching, which is controllable and can be applied to films of different specifications. The required equipment is also simple, and no complex equipment such as corona rollers and electrodes is required, only equipment that can apply the treatment agent to the surface of the film is required. The processing method of the present application is particularly beneficial to improving the surface properties of ultra-thin films. For example, the ultra-thin film in the composite current collector is only a micron-level film. If it is treated by corona treatment or the like, although its surface tension can be improved, it is difficult to uniformly process all parts of the film surface. On the other hand, since the film thickness is only a few microns, industrial corona treatment is not easy to balance the corona degree and the mechanical properties of the ultra-thin film, which can easily cause a significant loss of mechanical properties. The processing method of the present application, especially the micro-etching process, can be configured to achieve micro-etching corresponding to the thickness of the ultra-thin film, so that it will not significantly affect the mechanical properties of the ultra-thin film, thereby ensuring the quality, safety and service life of downstream products.

[0007] Furthermore, the chemical micro-etching is configured to make the surface dyne value greater than 36; the film mechanical strength before and after micro-etching decreases by ≤2%. Furthermore, the chemical micro-etching makes the surface dyne value greater than 38. The film mechanical strength before and after micro-etching decreases by ≤1%.

[0008] Furthermore, the chemical micro-etching action thickness is ≤1 μm; the chemical micro-etching action thickness is the deepest etching position depth of the chemical micro-etching.

[0009] Furthermore, the thickness range of the thin film is 1.5 to 20 μm. More specifically, the thickness range of the thin film is 1.5 to 10 μm. Further, the micro-etching at least includes chemical micro-etching with an etching thickness of ≤1 μm; more specifically, the chemical micro-etching includes an etching depth range of 10 nm to 1 μm. For ultra-thin films with a thickness of only a few micrometers, when their surfaces need to be compounded with other layers, such as when the ultra-thin film in the composite current collector needs to be compounded with a metal foil layer; in this case, the corresponding surface properties of the thin film need to be improved so that the metal layer can adhere tightly and stably to the thin film substrate layer. By using the thin film processing method of the present application, the compounding effect between the thin film surface and the metal foil layer can be improved. It should be noted that the processing method of the present application can be combined with the corresponding ultra-thin film thickness to achieve nano-level micro-etching, improving the controllability of surface treatment. Compared with the corona surface treatment method of the composite current collector ultra-thin film, it can ensure that the mechanical properties are not significantly affected while improving the surface adhesion performance.

[0010] Further, the thin film includes PET film, PP film, PI film, PE film, PVC film, PBT film, PC film, PS film, ABS film, PA film, PASF film, PVDF film, PEDOT film, PANI film, and PPy film. Further, the thin film is PET film, PP film, PI film; that is, it includes PET (polyethylene terephthalate), pp (polypropylene), PI (polyimide), PE (polyethylene), PVC (polyvinyl chloride), PBT (polybutylene terephthalate), PC (polycarbonate), PS (polystyrene), ABS (ternary copolymer of acrylonitrile (A)-butadiene (B)-styrene (S)), PA (polyamide), PASF (polyarylsulfone), PVDF (polyvinylidene fluoride), PEDOT (poly(3,4-ethylenedioxythiophene)), PANI (polyaniline), and PPy (polypyrrole) corresponding formed thin films. More specifically, the thin film is PP film. In the prior art, when using the corona treatment method to treat PP film, compared with other commonly used ultra-thin films for current collectors, the mechanical properties of the PP material ultra-thin film are more significantly negatively affected. Based on the composition of the present invention, it can replace the corona treatment method of the ultra-thin film and ensure the mechanical strength, especially for PP film, which is significantly different from the effect of corona treatment.

[0011] Further, the chemical treatment agent comprises Component A: acrylic resin; Component B: silane compound; Component C: etching component; and the ratio of Component A, Component B, and Component C is (5 - 10)∶(10 - 30)∶(0.1 - 10). Further, the chemical treatment agent further comprises Component D: glacial acetic acid, and the ratio of Component A, Component B, Component C, and Component D is (5 - 10)∶(10 - 30)∶(0.1 - 10)∶(0.5 - 3); further, it further comprises Component E: wetting agent, and the ratio of Component A, Component B, Component C, Component D, and Component E is (5 - 10)∶(10 - 30)∶(0.1 - 10)∶(0.5 - 3)∶(0.1 - 0.5). Further, an appropriate amount of water component is also included. Furthermore, the acrylic resin at least serves as a binder and includes silane compounds such as the amino silane and / or its oligomer, and / or, epoxy group silane and / or its oligomer at least serves as an adhesion promoter; it should be noted that the above-mentioned Component A and Component B are not limited to the binding or adhesion promoting effects, and here in this application, at least their main functions in the chemical treatment agent are used to illustrate the functions of the corresponding components.

[0012] The etching component is used to micro-etch the surface of the thin film, at least increasing the surface roughness of the thin film and improving the surface tension and wettability of the thin film; and by configuring the ratio and dosage of the etching component acting on the surface of the thin film, etching with a thickness at the nanometer level can be achieved, reducing the impact on the mechanical properties of the thin film while changing the surface properties of the thin film. Component A acrylic resin and the silane compound in Component B can endow the surface of the thin film with viscosity and enhance the adhesion of the thin film, at least providing diverse binding effects through surface groups respectively, so as to achieve binding with the surface of the thin film and binding with the surface of one side of the metal layer. It is worth noting that after the chemical treatment agent acts on the surface of the thin film for a certain period of time, with the partial curing of the treatment agent, the treatment agent on the surface of the thin film forms a micro-layer on the surface of the thin film. Based on the characteristics of multiple components including acrylic resin, this composition micro-layer has high mechanical properties, thereby compensating for the possible loss of the mechanical properties of the thin film due to etching through its mechanical properties while the composition is being etched. That is, it replaces the corona treatment to enhance the adhesion of the thin film while ensuring that the mechanical properties of the thin film do not decline. While the treatment agent micro-etches to change the surface properties of the thin film, it compensates for the possible mechanical property losses, forming a thin film substrate with both final surface improvement and mechanical properties. Further, the mechanical properties include breaking strength and elongation at break.

[0013] The acrylic resin includes its polymers, such as polyacrylic acid, hydroxy acrylic resin, poly(methyl acrylate) (PMA), poly(ethyl acrylate) (PEA), or acrylate esters such as derivatives thereof, poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA), or methacrylate esters such as derivatives thereof, or maleic acid-acrylic acid copolymer, but not limited thereto; specifically, the acrylic resin can be a commercially available acrylic resin, polyacrylic acid emulsion, acrylic polymer, such as Mitsubishi MB-2595 acrylic resin in Japan, Boxing B-30 acrylic resin, Nanjing Gutian 445N acrylic polymer, etc.; the maleic acid-acrylic acid copolymer can be the 479N maleic acid-acrylic acid copolymer sold by Nanjing Gutian Chemical Industry, or can also be a type of maleic acid-acrylic acid copolymer often used as a water treatment agent or dispersant, such as the maleic acid-acrylic acid copolymer sold by Shandong Taihe Science & Technology Co., Ltd. as a water treatment agent (CAS No. 26677-99-6), and also such as the maleic acid-acrylic acid copolymer sold by BASF as a dispersant (Sokalan CP9); the polyacrylic acid emulsion can be the product sold by Runchang Chemical Industry, such as Runchang Chemical Industry 6069 polyacrylic acid emulsion.

[0014] Further, the B-component silane compounds include: amino silane and / or its oligomer, and / or, epoxy silane and / or its oligomer. The amino silane, amino silane oligomer, epoxy silane, and epoxy silane oligomer can all be products of the prior art. For example, the amino silane oligomer can be commercially available products such as γ-aminopropylmethyldiethoxysilane (KH-902), Crosile 8150, Crosile 5203, USi-O1302 amino silane oligomer, QX-1250 amino silane oligomer, Jinrunna KRN8025, Quanxi Silicon Industry 1146 amino silane oligomer, Evonik Dynasylan 1146, and Evonik Dynasylan SIVO 260. The epoxy silane oligomer can be commercially available products such as USi-O2301 of Nanjing Liansil Chemical Co., Ltd., SICO-OP200 of Shandong Sike New Materials Co., Ltd., etc.

[0015] Further, the B-component includes: amino silane and / or its oligomer, and, epoxy silane and / or its oligomer, and the ratio between the amino silane and / or its oligomer and the epoxy silane and / or its oligomer is 1:3 to 3:1. Further still, the ratio between the amino silane and / or its oligomer and the epoxy silane and / or its oligomer is 1:1 to 3:1.

[0016] Further, the etching component in Component C includes phosphates, peroxides, and / or oxidized high-valence metal ions. Further, the phosphates include ammonium phosphate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, potassium phosphate, dipotassium hydrogen phosphate, potassium dihydrogen phosphate, sodium phosphate, disodium hydrogen phosphate, sodium dihydrogen phosphate, ammonium phosphate, calcium phosphate, lithium phosphate, and N-butylpyridinium hexafluorophosphate. Further, the peroxides include hydrogen peroxide, ammonium persulfate, potassium persulfate, benzoyl peroxide, tert-butyl peroxybenzoate, methyl ethyl ketone peroxide, ethyl peroxybenzene, 4,4'-dibenzoyl peroxide, sodium bisulfate persulfate, potassium bisulfate persulfate, calcium bisulfate persulfate, sodium peroxide, calcium peroxide, potassium peroxide, and organic peroxides. Further, the oxidized high-valence metal ions include metal ions with a valence of +2 or higher. Selection can be made among metal ions with a valence of +2 or higher, and examples include Fe3+, V2+, V3+, V4+, V5+, and Cr6+. Further still, the oxidized high-valence metal ions can exist in the form of compounds combined with other ions. Further, the molecular weight of the acrylic resin in Composition A is 3000 to 20000. Further, the particle size of the acrylic resin in Composition A is 0.05 to 0.2 μm. Further, the wetting agent in Component E includes fluorine-containing surface wetting agents such as FC-4430 (fluorosurfactant FC-4430) in the prior art.

[0017] Further, in step S1, the treatment agent is applied to the surface of the film by means of roll coating, spraying, and / or immersion. Since the treatment agent is a liquid component, the treatment agent can be applied by various methods such as roll coating, spraying, or immersion in this application; when using the roll coating method, the treatment agent components can be spread more evenly on the surface of the film; the surface properties of the film are relatively uniform; when using the spraying method, it is convenient to improve the processing speed. When only micro-etching is required in a short time, the treatment agent can be quickly applied by the spraying method, and it is beneficial for the film after the application of the treatment agent to enter the downstream process, controlling the degree and time of micro-etching of the treatment agent; if the immersion method is used, it is convenient to etch thicker films, while improving the application efficiency and accelerating the production speed. Based on the processing method of this application, the corresponding treatment agent application method can be adopted according to the actual film characteristics.

[0018] Further, it further includes the step: S2, after chemically treating the film with the treatment agent, squeezing, blowing, and / or drying treatment is performed. After micro-etching, in this application, components such as water that no longer act on the surface of the film can be removed by squeezing, blowing, or drying, which is beneficial for controlling the etching degree, and is also beneficial for other components of the treatment agent that have already combined with the film to solidify on the surface of the film, promoting the firm combination with the film and compensating for the mechanical property impact caused by micro-etching.

[0019] Further, in step S2, after the chemical treatment agent micro-etching the film for 5 to 20 s, squeezing, air drying and / or drying treatments are performed. Further still, a drying treatment is performed, and the film is dried at 20 to 40 °C for 5 to 60 s.

[0020] Further, a post-treatment step is further included: coating a glue solution on the surface of the film after chemical micro-etching to form a glue layer. Specifically, the post-treatment step can be carried out after the squeezing, air drying and / or drying treatments are completed. Further still, a release film is covered on the glue layer.

[0021] Another object of the present invention is to provide a film obtained by the foregoing film processing method. Based on the film prepared by the foregoing processing method, it has both the improvement of surface adhesion performance and the guarantee of mechanical properties, and when compensating for the mechanical strength during the micro-etching in step S1, when the treatment agent contains an acrylic resin component, while improving the adhesion strength, the mechanical properties may be further improved.

[0022] Another object of the present invention is to provide a composite current collector, including the foregoing film and foil layers on both sides of the film. Based on the film prepared by the foregoing processing method, the metal foil layer can be firmly bonded. The formed composite current collector can effectively overcome the situation that it is easy to fall off between the foil layer and the film substrate layer, which is beneficial to improving the safety, stability and overall quality of the composite current collector during use.

[0023] Another object of the present invention is to provide a battery, including the foregoing film and / or the foregoing composite current collector. In addition to the advantages of high energy density brought by the composite current collector itself, and based on the foregoing film or composite current collector, the service life, stability and safety of the battery are improved.

[0024] Compared with the prior art, the beneficial effects of the present application are as follows: By micro-etching the surface of the film, the present application can change the surface properties of the film, including roughness, surface tension, etc., improving the surface adhesion; facilitating the compounding with other layer structures, especially with the metal layer, and maintaining a stable compound state. At the same time, compared with methods such as corona treatment, the micro-etching in the present application causes less loss of the mechanical strength of the film. Micro-etching can improve the surface properties of the film while avoiding the impact on the mechanical strength. Through this processing method, it can replace methods such as corona treatment and avoid the obvious mechanical property loss caused by changing the surface properties of the film in the corona treatment method. Moreover, the processing method is simple, only requiring micro-etching with a certain amount of treatment agent, and the application amount, action time, etc. can also be configured to control the degree of micro-etching, which has controllability and can be applied to films of different specifications. The required equipment is also simple, without the need for complex equipment such as corona treatment, only requiring equipment that can apply the treatment agent to the film surface. The method of the present application has a simple production process, requires simple equipment, and has a low cost and a wide application range; the obtained film has both improved adhesion and guaranteed mechanical properties, and the performance is uniform; based on the film obtained by the processing method of the present application, the service life, safety, etc. of the corresponding downstream products such as composite current collectors and batteries can be improved, making the overall product quality excellent. Detailed implementation manners

[0025] The embodiments of the present invention are only for illustrative purposes and should not be construed as limiting the present invention. The technical solutions of the present invention will be clearly and completely described below in conjunction with the specific implementation manners. However, those skilled in the art will understand that the following described embodiments are some embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention. For those conditions not specified in the embodiments, they shall be carried out according to the conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase. Example 1

[0026] This example discloses a film processing method, including the steps: S1. Apply a chemical treatment agent to the surface of the film and perform chemical micro-etching on the surface of the film; and compensate for the mechanical properties of the film while chemically micro-etching the surface of the film. The mechanical properties include breaking strength and / or elongation at break.

[0027] This example also includes the step: S2. After treating the film with the chemical treatment agent, perform squeezing, air drying, and / or drying treatment.

[0028] In step S1, the treatment agent is applied to the surface of the film by means of roll coating, spraying and / or dipping. In step S2, after the film is micro-etched with the chemical treatment agent for 5 to 20 s, squeezing, air drying and / or drying treatment is carried out; in this embodiment, drying treatment is adopted, and it is dried at 20 to 40 °C for 5 to 60 s.

[0029] In industrial production, it can be understood that the film is unrolled to the processing area, then the chemical treatment agent is applied to the film in the processing area, and after continuing to drive for a preset distance or time, the components that do not continue to act on the surface are discharged; then the film with the surface chemically micro-etched is wound up; that is, the processed film is obtained.

[0030] After changing the surface properties of the film, in order to facilitate the subsequent production of composite foil materials such as composite current collectors, a glue layer can also be coated on the surface for composite with other layers. That is, it also includes a post-treatment step: coating a glue solution on the surface of the film after chemical micro-etching to form a glue layer. When adopting an off-line production mode, the processed film needs to be temporarily stored. For the convenience of winding and storage, a release film can be coated on the glue layer.

[0031] In this embodiment, the action thickness of the chemical micro-etching ≤ 1 μm; the action thickness of the chemical micro-etching is the depth of the deepest etching position of the chemical micro-etching. The film thickness range in this embodiment is 1.5 to 10 μm.

[0032] The film can be a PET film, a PP film, a PI film, a PE film, a PVC film, a PBT film, a PC film, a PS film, an ABS film, a PA film, a PASF film, a PVDF film, a PEDOT film, a PANI film and a PPy film. In this embodiment, the film is a PET film.

[0033] The chemical treatment agent used contains Component A: acrylic resin; Component B: silane compound; Component C: etching component; and the ratio of Component A, Component B, and Component C is (5-10):(10-30):(0.1-10). To improve the treatment effect, the chemical treatment agent further contains Component D: glacial acetic acid, and the ratio of Component A, Component B, Component C, and Component D is (5-10):(10-30):(0.1-10):(0.5-3); it may further contain Component E: wetting agent, and the ratio of Component A, Component B, Component C, Component D, and Component E is (5-10):(10-30):(0.1-10):(0.5-3):(0.1-0.5). Further, an appropriate amount of water component is also included; preferably, the ratio of Component A, Component B, and Component C is 5:15:0.5. For example, the chemical treatment agent is obtained by diluting the chemical treatment stock solution by ten times. The chemical treatment stock solution may include 5% of Component A, 15% of Component B, 0.5% of Component C, and the balance up to 100% of water; when Component D is contained and the ratio of Component A, Component B, Component C, and Component D is 5:15:0.5:0.5, or when Components D and E are contained and the ratio of Component A, Component B, Component C, Component D, and Component E is 5:15:0.5:0.5:0.1, then the aforementioned chemical treatment stock solution may correspondingly be: 5% of Component A, 15% of Component B, 0.5% of Component C, 0.5% of Component D, and the balance up to 100% of water, or 5% of Component A, 15% of Component B, 0.5% of Component C, 0.5% of Component D, 0.1% of Component E, and the balance up to 100% of water, etc. The silane compound of Component B includes: amino silane and / or its oligomer, and / or, epoxy silane and / or its oligomer. Further, the acrylic resin serves at least as a binder, and the amino silane and / or its oligomer, and / or, epoxy silane and / or its oligomer serve at least as an adhesion promoter; it should be noted that the aforementioned Component A and Component B are not limited to the binding or adhesion promoting effects. Herein, the present application at least illustrates the corresponding component functions based on their main functions in the chemical treatment agent.

[0034] The acrylic resin includes its polymers, such as polyacrylic acid, hydroxy acrylic resin, poly(methyl acrylate) (PMA), poly(ethyl acrylate) (PEA), or acrylate derivatives such as these, poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA), or methacrylate derivatives such as these, or maleic acid-acrylic acid copolymer, but not limited thereto; specifically, the acrylic resin can be a commercially available acrylic resin, polyacrylic acid emulsion, acrylic polymer, such as Mitsubishi MB-2595 acrylic resin in Japan, Boxing B-30 acrylic resin, Nanjing Gutian 445N acrylic polymer, etc.; the maleic acid-acrylic acid copolymer can be the 479N maleic acid-acrylic acid copolymer sold by Nanjing Gutian Chemical Industry, or can also be a type of maleic acid-acrylic acid copolymer often used as a water treatment agent or dispersant, such as the maleic acid-acrylic acid copolymer sold by Shandong Taihe Science & Technology Co., Ltd. as a water treatment agent (CAS No. 26677-99-6), or the maleic acid-acrylic acid copolymer sold by BASF as a dispersant (Sokalan CP9); the polyacrylic acid emulsion can be the product sold by Runchang Chemical Industry, such as Runchang Chemical Industry 6069 polyacrylic acid emulsion. Further, the amino silane, amino silane oligomer, epoxy silane, and epoxy silane oligomer can all be products of the prior art. For example, the amino silane oligomer can be commercially available products such as γ-aminopropylmethyldiethoxysilane (KH-902), Crosile 8150, Crosile 5203, USi-O1302 amino silane oligomer, QX-1250 amino silane oligomer, Jinrunna KRN8025, Quanxi Silicon Industry 1146 amino silane oligomer, Evonik Dynasylan1146, and Evonik Dynasylan SIVO 260, and the epoxy silane oligomer can be commercially available products such as USi-O2301 of Nanjing Liansil Chemical Co., Ltd. and SICO-OP200 of Shandong Sike New Materials Co., Ltd.

[0035] Component B includes: amino silane and / or its oligomer, and epoxy silane and / or its oligomer, and the ratio between the amino silane and / or its oligomer and the epoxy silane and / or its oligomer is 1:3 to 3:1. In this example, amino silane and epoxy silane are used, and the ratio between the two is 3:1.

[0036] The etching component in Component C includes phosphates, peroxides, and / or highly oxidized metal ions with oxidizing properties. The phosphates include ammonium phosphate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, potassium phosphate, dipotassium hydrogen phosphate, potassium dihydrogen phosphate, sodium phosphate, disodium hydrogen phosphate, sodium dihydrogen phosphate, ammonium phosphate, calcium phosphate, lithium phosphate, and N-butylpyridinium hexafluorophosphate. Further, the peroxides include hydrogen peroxide, ammonium persulfate, potassium persulfate, benzoyl peroxide, tert-butyl benzoyl peroxide, methyl ethyl ketone peroxide, ethyl peroxybenzene, 4,4'-dibenzoyl peroxide, sodium bisulfate persulfate, potassium bisulfate persulfate, calcium bisulfate persulfate, sodium peroxide, calcium peroxide, potassium peroxide, and organic peroxides. Further, the highly oxidized metal ions with oxidizing properties are metal ions with a valence of +2 or higher. Selection can be made among metal ions with a valence of +2 or higher, and examples include Fe3+, V2+, V3+, V4+, V5+, Cr6+. The highly oxidized metal ions with oxidizing properties can exist in the form of compounds combined with other ions. In this example, sodium phosphate is used.

[0037] The molecular weight of the acrylic resin in the A composition is 3000 - 20000. Further, the particle size of the acrylic resin in the A composition is 0.05 - 0.2 μm. Further, the wetting agent in Component E includes fluorine-containing surface wetting agents, such as the prior art FC-4430 (fluorosurfactant FC-4430), etc. Example 2

[0038] This example is based on the film processing method of the foregoing Example 1 to obtain the corresponding film. Using materials existing in the prior art, first prepare the chemical treatment stock solution composition according to Table 1 below. The acrylic resin can be the 479N maleic anhydride-acrylic copolymer from Nanjing Gutian, the aminosilane can be Evonik Dynasylan 1146, the epoxy silane can be USi-O2301 from Nanjing Liansil Chemical Co., Ltd., the phosphate can be disodium hydrogen phosphate, the peroxide can be potassium persulfate, and the highly oxidized metal ions with oxidizing properties can be V4+. Then dilute each composition by 10 times, apply it to a 3.6 μm PP film for micro-etching for 5 - 20 s, and then perform a drying treatment to obtain the corresponding film. The test group films prepared based on the foregoing processing method have both improved surface adhesion performance and guaranteed mechanical properties.

[0039] Table 1 Raw material name Test group 1 Test group 2 Test group 3 Test group 4 Acrylic resin 7 5 10 9 Aminosilane and / or its polymer 18 11.2 5 5 Epoxysilane and / or its polymer 6 3.8 6 15 Phosphate 0.1 8 Peroxide 0.7 Oxidizing high-valent metal ions 5 Deionized water To 100 To 100 To 100 To 100 Example 3

[0040] In this embodiment, performance comparisons were made between untreated PP films, films of Example 2 prepared by the processing method of the present application with chemical micro-etching, and films processed by corona treatment; for each composition, at least 4 groups were tested, and the average value was taken as the test result of the film corresponding to the composition. The untreated films were all 3.6 μm films. The corona treatment process included adjusting the parameters of the corona treatment machine to increase the surface dyne value of the treated film to about 34 - 36.

[0041] The test results are shown in Table 2 below.

[0042] Table 2 Tensile strength (longitudinal / Mpa) Tensile strength (transverse / Mpa) Elongation at break (longitudinal / %) Elongation at break (transverse / %) Dyne value Original PP film 164.6 180.2 51.8 42.0 ＜32 Test group 1 159.1 175.3 46.3 39.1 36 Test group 2 164.5 179.8 47.6 42.1 38 Test group 3 161.3 180.3 49.3 40.3 36 Test group 4 164.0 178.2 48.7 40.9 38 Corona group 1 126.1 140.8 27.3 23.2 34 Corona group 2 137.1 123.1 34.4 18.9 36 Corona group 3 114.9 106.6 25.0 14.7 34

[0043] As shown by the comparison results, corona treatment will cause a significant decrease in mechanical properties such as breaking strength and elongation at break. For example, the decrease ratio of breaking strength is as much as 20% - 30%, and the decrease ratio of elongation at break is as much as 40% - 50%; while adopting the micro-etching method of the present application, the mechanical properties after treatment basically do not change significantly, and the surface properties are significantly improved. That is, compared with corona treatment, based on the processing method of the present application, the mechanical properties of the original ultra-thin film can be retained, and excellent surface property improvement effects can be achieved. Example 4

[0044] This embodiment discloses a composite current collector, including the aforementioned film and foil layers on both sides of the film. Based on the film prepared by the aforementioned processing method, the metal foil layer can be firmly bonded. The formed composite current collector can effectively overcome the situation that the foil layer is easily detached from the film substrate layer, which is beneficial to improving the safety, stability and overall quality of the composite current collector. Example 5

[0045] This embodiment discloses a battery, including the aforementioned film and / or the aforementioned composite current collector. In addition to the advantages such as high energy density brought by the composite current collector itself, and based on the aforementioned film or composite current collector, the service life, stability and safety of the battery are improved.

[0046] Obviously, the above-mentioned embodiments of the present invention are merely examples for clearly illustrating the technical solutions of the present invention, rather than limitations on the specific implementation manners of the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principle of the claims of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. A film processing method, characterized in that, Including the steps: S1. Apply a chemical treatment agent to the surface of the film and perform chemical micro-etching on the film surface; And while chemically micro-etching the film surface, compensate for the mechanical properties of the film; The mechanical properties include breaking strength and / or elongation at break.

2. The film processing method according to claim 1, characterized in that, The thickness range of the film is 1.5 - 20 μm; and / or, the film includes PET film, PP film, PI film, PE film, PVC film, PBT film, PC film, PS film, ABS film, PA film, PASF film, PVDF film, PEDOT film, PANI film, and PPy film.

3. The film processing method according to claim 1, wherein The chemical treatment agent contains component A: acrylic resin; component B: silane compound; component C: etching component; and the ratio of component A, component B, and component C is (5 - 10)∶(10 - 30)∶(0.1 - 10).

4. The film processing method according to claim 3, characterized in that, The chemical treatment agent further contains component D: glacial acetic acid, and the ratio of component A, component B, component C, and component D is (5 - 10)∶(10 - 30)∶(0.1 - 10)∶(0.5 - 3); further, it also contains component E: wetting agent, and the ratio of component A, component B, component C, component D, and component E is (5 - 10)∶(10 - 30)∶(0.1 - 10)∶(0.5 - 3)∶(0.1 - 0.5).

5. The film processing method according to any one of claims 1 to 4, characterized in that, In step S1, the chemical treatment agent is applied to the film surface by roll coating, spraying, and / or dipping; and / or, it further includes the step: S2. After the film is treated with the chemical treatment agent, perform squeezing, air drying, and / or drying treatment.

6. The thin film processing method according to any one of claims 1 to 4, characterized in that It further includes a post-treatment step: coat a glue solution on the surface of the film after chemical micro-etching to form a glue layer.

7. The film processing method according to claim 6, characterized in that Cover a release film on the glue layer.

8. A film obtained by the film processing method according to any one of claims 1 - 7.

9. A method for producing a composite current collector, the composite current collector comprising a thin film and a foil layer located on at least one side of the thin film, characterized in that, Including the film processing method according to any one of claims 1 - 7, and a step of laminating the film with a foil layer.

10. A composite current collector, characterized in that, Including the film according to claim 8 and foil layers on both sides of the film; or, prepared by using the composite current collector production method according to claim 9.

11. A battery, characterized in that, Including the film according to claim 8 and / or the composite current collector according to claim 10.