Aluminum-plastic film without powder falling during shell punching and preparation method of aluminum-plastic film

Abstract

The invention belongs to the technical field of aluminum plastic films, and particularly relates to an aluminum plastic film without powder falling during shell punching and a preparation method thereof.The aluminum plastic film comprises a hardened layer, a PA layer, a bonding layer, an aluminum foil layer and a CPP layer which are sequentially stacked; wherein the hardened layer is formed by a thermocuring composition, and the thermocuring composition comprises the following components in parts by mass: 40-50 parts of polyacrylate polyol, 10-20 parts of a polyfunctional thiol compound, 5-10 parts of a hardening agent, 1-5 parts of an antifouling auxiliary agent and 12-20 parts of an ethyl acetate solvent; the hardened layer is formed by the thermosetting composition containing the polyacrylate polyol and the polyfunctional thiol compound, and in the coating curing process, the antifouling auxiliary agent is migrated to the surface of the hardened film along with volatilization of a solvent, so that a coating with a smooth effect is formed.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum-plastic films, and in particular relates to an aluminum-plastic film for punching shells without losing powder and a preparation method thereof. Background Art

[0002] In order to improve the punching performance of aluminum-plastic film, lubricants such as erucic acid amide are generally applied to the CPP surface and the outer protective layer during the manufacturing process of aluminum-plastic film to obtain sufficient punching depth. However, the aluminum-plastic film coated with lubricants is constantly rubbed against the mold during the punching process of the shell punching machine, and some erucic acid amide will remain on the mold, causing punching pits and powder falling off. This will cause the appearance quality of the aluminum-plastic film to deteriorate, and defects such as spots and scratches will appear, affecting the aesthetics of the product. In addition, powder falling may also affect the electrical performance test results of the battery, increasing the defective rate of the product.

[0003] Therefore, how to overcome the powdering defect caused by coating the aluminum-plastic film with lubricants such as erucic acid amide is a technical problem that needs to be solved urgently in this field.

[0004] It should be noted that the above information disclosed in this background technology section is only used to understand the background technology of the present application concept, and therefore, the above description is not considered to constitute information of the prior art. Summary of the invention

[0005] The disclosed embodiments at least provide an aluminum-plastic film that does not shed powder when punching shells and a preparation method thereof.

[0006] In the first aspect, an embodiment of the present disclosure provides an aluminum-plastic film for punching shells without powdering, comprising: a hardening layer, a PA layer, an adhesive layer, an aluminum foil layer and a CPP layer stacked in sequence; wherein the hardening layer is formed by a thermosetting composition, and the thermosetting composition comprises the following components in parts by weight: 40-50 parts of polyacrylate polyol, 10-20 parts of a multifunctional thiol compound, 5-10 parts of a hardener, 1-5 parts of an antifouling agent and 12-20 parts of an ethyl acetate solvent.

[0007] In an optional embodiment, the multifunctional thiol compound includes any one or more combinations of pentaerythritol tetrakis(3-mercaptopropionate), trimethylolpropane tris(3-mercaptopropionate) and bis(3-mercaptopropionate)ethylene glycol.

[0008] In an optional embodiment, the antifouling agent includes any one or more combinations of trifluorochlorosilane, 3-epoxypropyltriethoxysilane and fluorinated alkyl phosphate.

[0009] In an optional embodiment, the thickness of the hardened layer is 1-2 μm.

[0010] In an optional embodiment, the PA layer has a thickness of 15-25 μm.

[0011] In an optional embodiment, the thickness of the bonding layer is 3-5 μm.

[0012] In an optional embodiment, the thickness of the CPP layer is 38-54 μm.

[0013] In an optional embodiment, the CPP layer includes an adhesive layer, a support layer and a heat-sealing layer stacked in sequence; wherein the adhesive layer is formed by mixing maleic anhydride-modified polypropylene and binary copolymer polypropylene; the support layer is formed by polypropylene homopolymer; and the heat-sealing layer is formed by mixing silicone masterbatch and ternary copolymer polypropylene.

[0014] In the second aspect, the embodiment of the present disclosure also provides a method for preparing the non-powdering aluminum-plastic film for punching shells as described above, comprising the following steps: step S1, preparing a thermosetting composition and coating it on one side surface of the PA layer, heating it at high temperature to obtain a hardened layer; step S2, preparing a polyurethane glue and coating it on the other side surface of the PA layer, and compounding it with the matte surface of the aluminum foil layer at 80-90°C after high-temperature heating, and the polyurethane glue forms a bonding layer; step S3, compounding the CPP layer with the bright surface of the aluminum foil layer at 200-220°C to obtain a non-powdering aluminum-plastic film for punching shells.

[0015] The beneficial effect of the present invention is that the non-powdering aluminum-plastic film for punching shells and its preparation method form a hardened layer by a thermosetting composition containing polyacrylate polyols and multifunctional thiol compounds. During the coating curing process, the anti-fouling additive migrates to the surface of the hardened film as the solvent evaporates to form a coating with a slippery effect, thereby eliminating the step of applying the slippery agent in the aluminum-plastic film manufacturing process and providing the aluminum-plastic film with sufficient punching depth, thereby further improving the processing performance of the aluminum-plastic film and overcoming the powdering problem.

[0016] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.

[0017] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A schematic diagram of the structure of an aluminum-plastic film for punching shells without losing powder provided in an embodiment of the present disclosure;

[0020] Figure 2 A schematic diagram of the structure of a CPP layer provided in an embodiment of the present disclosure.

[0021] In the figure:

[0022] 1. Hardening layer; 2. PA layer; 3. Adhesive layer; 4. Aluminum foil layer; 5. CPP layer; 51. Adhesive layer; 52. Support layer; 53. Heat sealing layer. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] As used herein, the phrases "in one embodiment," "according to one embodiment," "in some embodiments," and the like generally refer to the fact that the particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present disclosure. Therefore, a particular feature, structure, or characteristic may be included in more than one embodiment of the present disclosure, so that these phrases do not necessarily refer to the same embodiment. As used herein, the terms "example," "exemplary," and the like are used to "serve as an example, instance, or illustration." Any implementation, aspect, or design described herein as "example" or "exemplary" is not necessarily to be construed as preferred or superior to other implementations, aspects, or designs. On the contrary, the use of the terms "example," "exemplary," and the like is intended to present concepts in a concrete manner.

[0025] Herein, example embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. As used herein, expressions such as "at least one of..." modify the entire list of elements when following a list of elements, rather than modifying individual elements in the list. For example, the expression "at least one of a, b, and c" should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0026] The terms used herein are only used to describe specific exemplary configurations and are not intended to be limited. As used herein, the singular articles "one", "an" and "the" may also be intended to include plural forms, unless it is clearly indicated above that this is not the case. The terms "comprise", "include" and "have" are inclusive, and therefore specify the presence of features, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components and / or combinations thereof. The method steps, processes and operations described herein should not be interpreted as necessarily requiring them to be performed in the specific order discussed or shown, unless specifically identified as an execution order. Additional or alternative steps may be adopted.

[0027] Glossary

[0028] As used herein, "CPP" refers to cast polypropylene film, "PA" refers to polyamide, and "HDI" refers to hexamethylene diisocyanate.

[0029] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0030] like Figure 1 As shown, an embodiment of the present disclosure provides an aluminum-plastic film for punching shells without powdering, comprising: a hardening layer, a PA layer, a bonding layer, an aluminum foil layer and a CPP layer stacked in sequence; wherein the hardening layer is formed by a thermosetting composition, and the thermosetting composition comprises the following components in parts by mass: 40-50 parts of polyacrylate polyol, 10-20 parts of a multifunctional thiol compound, 5-10 parts of a hardener, 1-5 parts of an antifouling agent and 12-20 parts of an ethyl acetate solvent; and the total parts of the polyacrylate polyol, the multifunctional thiol compound, the antifouling agent, the hardener and the ethyl acetate solvent is 100 parts.

[0031] In some embodiments, specifically, the multifunctional thiol compound includes any one or more combinations of pentaerythritol tetrakis(3-mercaptopropionate), trimethylolpropane tris(3-mercaptopropionate) and bis(3-mercaptopropionate)ethylene glycol.

[0032] In some embodiments, specifically, the antifouling agent includes any one or more combinations of trifluorochlorosilane, 3-epoxypropyltriethoxysilane and fluorinated alkyl phosphate.

[0033] In some embodiments, specifically, the thickness of the hardened layer is 1-2 μm.

[0034] In some embodiments, specifically, the thickness of the PA layer is 15-25 μm.

[0035] In some embodiments, specifically, the thickness of the bonding layer is 3-5 μm.

[0036] In some embodiments, specifically, the thickness of the CPP layer is 38-54 μm.

[0037] like Figure 2 As shown, specifically, the CPP layer includes an adhesive layer, a support layer and a heat-sealing layer stacked in sequence; wherein the adhesive layer is formed by mixing maleic anhydride-modified polypropylene and binary copolymer polypropylene; the support layer is formed by polypropylene homopolymer; and the heat-sealing layer is formed by mixing silicone masterbatch and ternary copolymer polypropylene.

[0038] The disclosed embodiment also provides a method for preparing the aforementioned non-powdering aluminum-plastic film for punching shells, comprising the following steps: step S1, preparing a thermosetting composition and coating it on one side surface of the PA layer, heating it at high temperature to obtain a hardened layer; step S2, preparing a polyurethane glue and coating it on the other side surface of the PA layer, and compounding it with the matte surface of the aluminum foil layer at 80-90°C after high-temperature heating, so that the polyurethane glue forms a bonding layer; step S3, compounding the CPP layer with the bright surface of the aluminum foil layer at 200-220°C to obtain the non-powdering aluminum-plastic film for punching shells.

[0039] The performance of the aluminum-plastic film provided by the present invention is tested according to the following method:

[0040] (1) Deep drawing performance

[0041] Punch holes with a shell punching machine. Start punching from 5.0mm, punch 10 samples continuously, check under strong light for no delamination, cracks, or pinholes, then increase by 0.2mm and continue punching for 10 more until it breaks. Record the punching depth before it breaks as the limit punching depth.

[0042] (2) Heat seal strength

[0043] Using a Japanese Tester Sangyo TP-701-B heat sealer, two 10×10 cm -2 The aluminum-plastic film of different sizes is aligned with the heat-sealing layer for heat sealing. After the sample cools to room temperature, the heat-sealing strength is tested using the Shimadzu AGS-X series electronic universal testing machine.

[0044] (3) Slippery performance

[0045] The friction coefficient between hardened layers is measured using the Friction Tester HM-3 friction coefficient measuring instrument produced by Toyo Seiki Co., Ltd. The smaller the friction coefficient, the better the lubricity.

[0046] Specifically, in a specific embodiment, the nylon layer is the PA layer, and the glue layer is the bonding layer.

[0047] Example 1

[0048] 45 parts of polyacrylate polyol, 17 parts of trimethylolpropane tris(3-mercaptopropionate), 8 parts of HDI, 4 parts of antifouling agent trifluorochlorosilane, and 26 parts of solvent ethyl acetate were mixed to obtain a heat-curing composition.

[0049] The above-mentioned heat-curable composition was applied to one surface of a nylon film having a thickness of 15 μm. After the formed coating was dried at 100°C for 4 minutes, a hardened layer was obtained, and the coating thickness was 1 μm.

[0050] The glue of model XH-50NT of Guangzhou Xinhui Chemical was prepared according to the recommended ratio, and then coated on the other side of the nylon film, and dried at 90°C for 1 minute to form a glue layer with a thickness of 3um.

[0051] After drying, the adhesive surface of the nylon film coated with the adhesive layer is thermally laminated with the matte surface of the aluminum foil treated with a 40 um surface acid-resistant agent at a lamination temperature of 70°C.

[0052] 60 parts of maleic anhydride modified polypropylene HP500N and 40 parts of binary copolymer polypropylene Dowlex TM 2530G was added to extruder A, 100 parts of polypropylene homopolymer FC801 were added to extruder B, 10 parts of silicone masterbatch and 90 parts of ternary copolymer polypropylene TF400 were added to extruder C, and at a temperature of 220°C, three layers were co-extruded to obtain a CPP film with a thickness of 54um.

[0053] The CPP is compounded with the bright surface of the aluminum foil with nylon film at a compounding temperature of 200° C. to obtain the final product.

[0054] Example 2

[0055] 40 parts of polyacrylate polyol, 20 parts of pentaerythritol tetrakis(3-mercaptopropionate), 5 parts of MDI, 5 parts of antifouling agent 3-epoxypropyltriethoxysilane, and 30 parts of solvent ethyl acetate were mixed to obtain a heat curing composition.

[0056] The above-mentioned heat-curable composition was coated on one surface of a nylon film having a thickness of 20 μm. After the formed coating was dried at 100°C for 4 minutes, a hardened layer was obtained, and the coating thickness was 2 μm.

[0057] The glue of model XH-50NT of Guangzhou Xinhui Chemical was prepared according to the recommended ratio, and then coated on the other side of the nylon film, and dried at 90°C for 1 minute to form a glue layer with a thickness of 3um.

[0058] After drying, the adhesive surface of the nylon film coated with the adhesive layer is thermally laminated with the matte surface of the aluminum foil treated with a 40 um surface acid-resistant agent at a lamination temperature of 70°C.

[0059] 70 parts of maleic anhydride modified polypropylene HP500N and 30 parts of binary copolymer polypropylene Dowlex TM 2530G was added to extruder A, 100 parts of polypropylene homopolymer FC801 was added to extruder B, 5 parts of silicone masterbatch and 95 parts of ternary copolymer polypropylene TF400 were added to extruder C, and the three layers were co-extruded at a temperature of 220°C to obtain a CPP film with a thickness of 48um.

[0060] The CPP is compounded with the bright surface of the aluminum foil with nylon film at a compounding temperature of 200° C. to obtain the final product.

[0061] Example 3

[0062] 50 parts of polyacrylate polyol, 10 parts of bis(3-mercaptopropionic acid)ethylene glycol, 10 parts of MDI, 2 parts of antifouling assistant fluorinated alkyl phosphate, and 28 parts of solvent ethyl acetate were mixed to obtain a heat curing composition.

[0063] The above-mentioned heat-curable composition was applied to one surface of a nylon film having a thickness of 15 μm. After the formed coating was dried at 100°C for 4 minutes, a hardened layer was obtained, and the coating thickness was 2 μm.

[0064] The glue of model XH-50NT of Guangzhou Xinhui Chemical was prepared according to the recommended ratio, and then coated on the other side of the nylon film, and dried at 90°C for 1 minute to form a glue layer with a thickness of 3um.

[0065] After drying, the adhesive surface of the nylon film coated with the adhesive layer is thermally laminated with the matte surface of the aluminum foil treated with a 55um surface acid-resistant agent at a lamination temperature of 70°C.

[0066] 50 parts of maleic anhydride modified polypropylene HP500N and 50 parts of binary copolymer polypropylene Dowlex TM 2530G was added to extruder A, 100 parts of polypropylene homopolymer FC801 were added to extruder B, 8 parts of silicone masterbatch and 92 parts of ternary copolymer polypropylene TF400 were added to extruder C, and at a temperature of 220°C, three layers were co-extruded to obtain a CPP film with a thickness of 38um.

[0067] The CPP is compounded with the bright surface of the aluminum foil with nylon film at a compounding temperature of 200° C. to obtain the final product.

[0068] Example 4

[0069] 50 parts of polyacrylate polyol, 15 parts of trimethylolpropane tris(3-mercaptopropionate), 10 parts of HDI, 5 parts of antifouling agent 3-epoxypropyltriethoxysilane, and 20 parts of solvent ethyl acetate were mixed to obtain a heat curing composition.

[0070] The above heat-curable composition was applied to one surface of a nylon film having a thickness of 25 μm. After the formed coating was dried at 100°C for 4 minutes, a hardened layer was obtained. The coating thickness was 1 μm.

[0071] The glue of model XH-50NT of Guangzhou Xinhui Chemical was prepared according to the recommended ratio, and then coated on the other side of the nylon film, and dried at 90°C for 1 minute to form a glue layer with a thickness of 3um.

[0072] After drying, the adhesive surface of the nylon film coated with the adhesive layer is thermally laminated with the matte surface of the aluminum foil treated with a 35 um surface acid-resistant agent at a lamination temperature of 70°C.

[0073] 55 parts of maleic anhydride modified polypropylene HP500N and 45 parts of binary copolymer polypropylene Dowlex TM 2530G was added to extruder A, 100 parts of polypropylene homopolymer FC801 were added to extruder B, 10 parts of silicone masterbatch and 90 parts of ternary copolymer polypropylene TF400 were added to extruder C, and the three layers were co-extruded at a temperature of 220°C to obtain a CPP film with a thickness of 49um.

[0074] The CPP is compounded with the bright surface of the aluminum foil with nylon film at a compounding temperature of 200° C. to obtain the final product.

[0075] Example 5

[0076] 42 parts of polyacrylate polyol, 18 parts of bis(3-mercaptopropionic acid)ethylene glycol, 7 parts of HDI, 3 parts of antifouling auxiliary agent fluorinated alkyl phosphate, and 30 parts of solvent ethyl acetate were mixed to obtain a heat curing composition.

[0077] The above heat-curable composition was applied to one surface of a nylon film having a thickness of 15 μm. After the formed coating was dried at 100°C for 4 minutes, a hardened layer was obtained. The coating thickness was 2 μm.

[0078] The glue of model XH-50NT of Guangzhou Xinhui Chemical was prepared according to the recommended ratio, and then coated on the other side of the nylon film, and dried at 90°C for 1 minute to form a glue layer with a thickness of 3um.

[0079] After drying, the adhesive surface of the nylon film coated with the adhesive layer is thermally laminated with the matte surface of the aluminum foil treated with a 40 um surface acid-resistant agent at a lamination temperature of 70°C.

[0080] 60 parts of maleic anhydride modified polypropylene HP500N and 40 parts of binary copolymer polypropylene Dowlex TM 2530G was added to extruder A, 100 parts of polypropylene homopolymer FC801 were added to extruder B, 10 parts of silicone masterbatch and 90 parts of ternary copolymer polypropylene TF400 were added to extruder C, and at a temperature of 220°C, three layers were co-extruded to obtain a CPP film with a thickness of 53um.

[0081] The CPP is compounded with the bright surface of the aluminum foil with nylon film at a compounding temperature of 200° C. to obtain the final product.

[0082] Comparative Example 1

[0083] 50 parts of polyacrylate polyol, 20 parts of trimethylolpropane tris(3-mercaptopropionate), 10 parts of HDI, and 20 parts of solvent ethyl acetate were mixed to obtain a heat curing composition.

[0084] The above heat-curable composition was applied to one surface of a nylon film having a thickness of 15 μm. After the formed coating was dried at 100°C for 4 minutes, a hardened layer was obtained. The coating thickness was 1 μm.

[0085] The glue of model XH-50NT of Guangzhou Xinhui Chemical was prepared according to the recommended ratio, and then coated on the other side of the nylon film, and dried at 90°C for 1 minute to form a glue layer with a thickness of 3um.

[0086] After drying, the adhesive surface of the nylon film coated with the adhesive layer is thermally laminated with the matte surface of the aluminum foil treated with a 40 um surface acid-resistant agent at a lamination temperature of 70°C.

[0087] 50 parts of maleic anhydride modified polypropylene HP500N and 50 parts of binary copolymer polypropylene Dowlex TM 2530G was added to extruder A, 100 parts of polypropylene homopolymer FC801 were added to extruder B, 10 parts of silicone masterbatch and 90 parts of ternary copolymer polypropylene TF400 were added to extruder C, and at a temperature of 220°C, three layers were co-extruded to obtain a CPP film with a thickness of 54um.

[0088] The CPP is compounded with the bright surface of the aluminum foil with nylon film at a compounding temperature of 200° C. to obtain the final product.

[0089] Compared with the technical solution provided in the embodiment, the difference of the heat curing composition provided in Comparative Example 1 is that no antifouling auxiliary agent is added in the formula.

[0090] Comparative Example 2

[0091] 45 parts of polyacrylate polyol, 17 parts of trimethylolpropane tris(3-mercaptopropionate), 8 parts of HDI, 4 parts of antifouling auxiliary agent fluorinated alkyl phosphate, and 26 parts of solvent ethyl acetate were mixed to obtain a heat curing composition.

[0092] The above heat-curable composition was applied to one surface of a nylon film having a thickness of 15 μm. After the formed coating was dried at 100°C for 4 minutes, a hardened layer was obtained. The coating thickness was 1 μm.

[0093] The glue of model XH-50NT of Guangzhou Xinhui Chemical was prepared according to the recommended ratio, and then coated on the other side of the nylon film, and dried at 90°C for 1 minute to form a glue layer with a thickness of 3um.

[0094] After drying, the adhesive surface of the nylon film coated with the adhesive layer is thermally laminated with the matte surface of the aluminum foil treated with a 40 um surface acid-resistant agent at a lamination temperature of 70°C.

[0095] 50 parts of maleic anhydride modified polypropylene HP500N and 50 parts of binary copolymer polypropylene Dowlex TM 2530G was added to extruder A, 100 parts of polypropylene homopolymer FC801 was added to extruder B, 100 parts of ternary copolymer polypropylene TF400 was added to extruder C, and at a temperature of 220°C, three layers were co-extruded to obtain a CPP film with a thickness of 54um.

[0096] The CPP is compounded with the bright surface of the aluminum foil with nylon film at a compounding temperature of 200° C. to obtain the final product.

[0097] Compared with the technical solution provided in the embodiment, the CPP provided in Comparative Example 2 is different in that no silicone masterbatch is added to the heat sealing layer.

[0098] Table 1 Performance test results of aluminum-plastic films provided by Examples 1-5 and Comparative Examples 1-2

[0099]

[0100]

[0101] Specifically, no antifouling agent was added to the hardened layer in Comparative Example 1, resulting in an increase in the friction coefficient of the hardened layer. No silicone masterbatch was added to the CPP layer in Comparative Example 2, resulting in an increase in the friction coefficient of the CPP. If the friction coefficient is too high, the aluminum-plastic film will have difficulty moving in the mold, which will increase the force required during the stamping process, easily causing damage to the shell, and reducing the shell depth of the aluminum-plastic film.

[0102] In summary, the present aluminum-plastic film for punching shells without losing powder and its preparation method forms a hardened layer by a thermosetting composition containing polyacrylate polyol and a multifunctional thiol compound, which eliminates the step of applying a lubricant in the aluminum-plastic film manufacturing process and provides a sufficient punching depth for the aluminum-plastic film, thereby further improving the processing performance of the aluminum-plastic film and overcoming the problem of powder loss.

[0103] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A non-powder-shedding aluminum-plastic film for punching shells, characterized in that: include: The hardening layer, PA layer, bonding layer, aluminum foil layer and CPP layer are stacked in sequence; The hardened layer is formed by a heat-curing composition, and the heat-curing composition includes the following components in parts by weight: 40-50 parts of polyacrylate polyol, 10-20 parts of multifunctional thiol compound, 5-10 parts of hardener, 1-5 parts of antifouling assistant and 12-20 parts of ethyl acetate solvent.

2. The powder-free aluminum-plastic film for punching shells as claimed in claim 1, characterized in that: The multifunctional thiol compound includes any one or more combinations of tetrakis(3-mercaptopropionate)pentaerythritol, trimethylolpropane tris(3-mercaptopropionate) and bis(3-mercaptopropionate)ethylene glycol.

3. The powder-free aluminum-plastic film for punching shells as claimed in claim 1, characterized in that: The antifouling agent includes any one or more combinations of trifluorochlorosilane, 3-epoxypropyltriethoxysilane and fluorinated alkyl phosphate.

4. The powder-free aluminum-plastic film for punching shells as claimed in claim 1, characterized in that: The thickness of the hardened layer is 1-2 μm.

5. The powder-free aluminum-plastic film for punching shells as claimed in claim 1, characterized in that: The thickness of the PA layer is 15-25 μm; The thickness of the bonding layer is 3-5 μm; The thickness of the CPP layer is 38-54 μm.

6. The powder-free aluminum-plastic film for punching shells as claimed in claim 1, characterized in that: The CPP layer comprises an adhesive layer, a support layer and a heat-sealing layer stacked in sequence; wherein The adhesive layer is formed by mixing maleic anhydride modified polypropylene and binary copolymer polypropylene; The support layer is formed of polypropylene homopolymer; The heat sealing layer is formed by mixing silicone masterbatch and terpolymer polypropylene.

7. A method for preparing a powder-free aluminum-plastic film for punching shells as claimed in any one of claims 1 to 9, characterized in that: The steps include: Step S1, preparing a heat curing composition and coating it on one surface of the PA layer, and heating at a high temperature to obtain a hardened layer; Step S2, preparing polyurethane glue and coating it on the other side of the PA layer, and then heating it at high temperature to compound it with the matte surface of the aluminum foil layer at 80-90° C., so that the polyurethane glue forms a bonding layer; Step S3, compounding the CPP layer and the bright surface of the aluminum foil layer at 200-220° C. to obtain an aluminum-plastic film that does not shed powder when punching shells.

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