Aluminum-plastic film, and preparation method thereof, and aluminum-plastic film

Abstract

The application belongs to the technical field of thin films for aluminum-plastic films, and particularly relates to a cast polypropylene film for aluminum-plastic films, a preparation method thereof and an aluminum-plastic film, which comprises a melt co-extruded corona layer, a support layer and a heat-sealing layer; wherein raw materials of the corona layer comprise main material ternary copolymerized polypropylene resin and auxiliary material homopolymerized polypropylene resin and silicon dioxide doped POE resin; raw materials of the support layer comprise main stream homopolymerized polypropylene resin and auxiliary material silicon dioxide doped POE resin and hyperbranched polyamide resin; and raw materials of the heat-sealing layer comprise main stream ternary copolymerized polypropylene resin and auxiliary material silicon dioxide doped POE resin and hyperbranched polyamide resin; different kinds of polypropylenes are used as main materials and different auxiliary materials are added to prepare the corona layer, the support layer and the heat-sealing layer respectively, and three-layer co-extrusion technology is adopted for integrated molding, so that the polarity problem of the film is improved.

Description

Technical Field

[0001] This invention belongs to the field of film technology for aluminum-plastic film, specifically relating to a cast polypropylene film for aluminum-plastic film and its preparation method, and aluminum-plastic film. Background Technology

[0002] Lithium-ion batteries have advantages such as high energy density and long cycle life, and have experienced rapid development in recent years. Currently, lithium-ion batteries are available in three packaging forms: steel casing, square aluminum casing, and soft-pack. Among them, soft-pack lithium-ion batteries, with their high energy density and safety, have seen an increasing share of the power battery market in recent years. Aluminum-plastic film is the main packaging material for soft-pack lithium batteries. It is mainly composed of a three-layer composite structure: from the outside in, nylon film and PET film, aluminum foil, and cast polypropylene. When the performance of the cast polypropylene is poor, it can cause the aluminum foil to short-circuit simultaneously with both the negative electrode and the electrolyte, significantly accelerating the corrosion rate of the aluminum foil. Therefore, the selection of cast polypropylene is relatively stringent, making it a key structural element in the aluminum-plastic film.

[0003] Cast polypropylene (CPP) is widely used in various packaging materials due to its good transparency, high gloss, good stiffness, good moisture resistance, heat resistance, excellent easy-to-seal properties at seams, low cost, and low density. However, traditional polypropylene films also exhibit some drawbacks. For example, due to their non-polar nature, they have a high adsorption capacity for low molecular weight solvent molecules, which affects the adhesion between them and other layers. Therefore, their insufficient adhesion performance leads to their inability to meet the electrolyte resistance requirements of next-generation lithium batteries.

[0004] Therefore, overcoming the polar adsorption problem of cast polypropylene is a technical problem that urgently needs to be solved in this field.

[0005] It should be noted that the information disclosed in this background section is only for understanding the background technology of the present application concept, and therefore, the above description is not considered to constitute prior art information. Summary of the Invention

[0006] This disclosure provides at least one example of a cast polypropylene film for aluminum-plastic film, a method for preparing the same, and an aluminum-plastic film.

[0007] In a first aspect, embodiments of this disclosure provide a cast polypropylene film for aluminum-plastic film, comprising: a melt-co-extruded corona layer, a support layer, and a heat-sealing layer; wherein the raw materials of the corona layer include the main material ternary copolymer polypropylene resin and the auxiliary materials homopolymer polypropylene resin and silica-doped POE resin; the raw materials of the support layer include mainstream homopolymer polypropylene resin and the auxiliary materials silica-doped POE resin and hyperbranched polyamide resin; the raw materials of the heat-sealing layer include mainstream ternary copolymer polypropylene resin and the auxiliary materials silica-doped POE resin and hyperbranched polyamide resin.

[0008] In one optional embodiment, the corona layer comprises the following components by mass parts: 40-50 parts of ternary copolymer polypropylene resin, 30-40 parts of homopolymer polypropylene resin, 5-15 parts of silica-doped POE resin, 2-8 parts of hyperbranched polyamide resin, and 1-5 parts of slip masterbatch.

[0009] In one optional embodiment, the support layer comprises the following components by weight: 75-85 parts homopolymer polypropylene resin, 5-10 parts silica-doped POE resin, 2-8 parts hyperbranched polyamide resin, and 1-7 parts slip masterbatch.

[0010] In one optional embodiment, the heat-sealing layer comprises the following components by weight: 80-90 parts of ternary copolymer polypropylene resin, 5-10 parts of silica-doped POE resin, 2-8 parts of hyperbranched amide resin, and 1-5 parts of slip masterbatch.

[0011] In one alternative embodiment, the melt flow rate of the ternary copolymer polypropylene resin is 6-8 g / 10 min.

[0012] In one optional embodiment, the silica doping content in the silica-doped POE resin is 3-10%.

[0013] In one alternative embodiment, the melt flow rate of the homopolymer polypropylene resin is 16-18 g / 10 min.

[0014] In one optional embodiment, the thickness ratio of the corona layer, the support layer, and the heat-sealing layer is (1-1.5):(2-3):(1-1.5); and the thickness of the cast polypropylene film for aluminum-plastic film is 30-90 μm.

[0015] Secondly, this disclosure also provides a method for preparing cast polypropylene film for aluminum-plastic film as described above, comprising the following steps: mixing various raw materials evenly in proportion and then feeding them cleanly by metering; setting the temperature of the melt extruder, filter, and transmission pipeline to 220-270℃, and the temperature of the distributor and T-die to 260-280℃; melting, shearing, and plasticizing the mixed materials through different extruder screws to obtain a melt; filtering the melt a second time through a filter; distributing the filtered melt in different proportions through a distributor, passing it through a T-die, and then casting it on a non-mirror surface, followed by cooling and crystallization to form a film, wherein the casting speed is 50-100 m / min to obtain a pre-formed film; measuring and adjusting the thickness of the pre-formed film, and then traction and winding it into a film after surface corona treatment.

[0016] Thirdly, embodiments of this disclosure also provide an aluminum-plastic film, which uses the cast polypropylene film for aluminum-plastic films as described above.

[0017] The beneficial effects of this invention are as follows: The aluminum-plastic film uses cast polypropylene film and its preparation method; different types of polypropylene are used as the main material and different auxiliary materials are added to prepare the corona layer, support layer, and heat-sealing layer respectively; and a three-layer co-extrusion technology is used for integral molding. The corona layer is mainly composed of ternary copolymer polypropylene resin and supplemented by polypropylene homopolymer. The addition of silica-doped POE resin reduces the crystallinity of the corona layer after film formation. With decreased crystallinity, the polarity of the corona layer increases during corona treatment, which is beneficial. It can be composited with materials such as aluminum foil; the support layer is mainly composed of polypropylene homopolymer, supplemented by hyperbranched resin and silica-doped POE resin. The addition of a small amount of inorganic matter can improve the stiffness of CPP film, while the addition of hyperbranched resin and POE resin can improve the ductility of CPP film; the heat-sealing layer is mainly composed of ternary copolymer polypropylene, with the addition of some silica-doped POE resin and hyperbranched polyester. The addition of inorganic matter in the heat-sealing layer can improve the residual rate of heat-sealing layer during heat sealing of CPP material, and improve heat sealing strength and electrolyte resistance.

[0018] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention are realized and obtained through the structures particularly pointed out in the description and the drawings.

[0019] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of a cast polypropylene film for aluminum-plastic film provided in an embodiment of this disclosure.

[0022] In the picture:

[0023] 1. Corona layer; 2. Support layer; 3. Heat seal layer. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] As used herein, the phrases “in one embodiment,” “according to one embodiment,” “in some embodiments,” etc., generally refer to the fact that a particular feature, structure, or characteristic following the phrase can be included in at least one embodiment of this disclosure. Therefore, a particular feature, structure, or characteristic can be included in more than one embodiment of this disclosure, such that these phrases do not necessarily refer to the same embodiment. As used herein, the terms “example,” “exemplary,” etc., 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. Rather, the use of the terms “example,” “exemplary,” etc., is intended to present concepts in a specific manner.

[0026] In this document, exemplary 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 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.

[0027] The terminology used herein is for the purpose of describing specific exemplary configurations only and is not intended to be limiting. As used herein, the singular articles “a,” “an,” and “the” may also be intended to include plural forms unless otherwise clearly stated herein. The terms “comprising,” “including,” and “having” are inclusive and thus specify the presence of features, steps, operations, elements, and / or components, but do not preclude 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 construed as requiring them to be performed in the specific order discussed or shown, unless specifically identified as such. Additional or alternative steps may be employed.

[0028] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0029] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0030] Please see Figure 1 ,like Figure 1 As shown in the embodiments of this disclosure, a cast polypropylene film for aluminum-plastic film is provided, comprising: a melt-co-extruded corona layer, a support layer, and a heat-sealing layer; wherein the raw materials of the corona layer include the main material ternary copolymer polypropylene resin and the auxiliary materials homopolymer polypropylene resin and silica-doped POE resin; the raw materials of the support layer include mainstream homopolymer polypropylene resin and the auxiliary materials silica-doped POE resin and hyperbranched polyamide resin; the raw materials of the heat-sealing layer include mainstream ternary copolymer polypropylene resin and the auxiliary materials silica-doped POE resin and hyperbranched polyamide resin.

[0031] This disclosure also provides a method for preparing cast polypropylene film for aluminum-plastic film as described above, comprising the following steps: mixing various raw materials evenly in proportion and then feeding them cleanly by metering; setting the temperature of the melt extruder, filter, and transmission pipeline to 220-270℃, and the temperature of the distributor and T-die to 260-280℃; melting, shearing, and plasticizing the mixed materials through different extruder screws to obtain a melt; filtering the melt a second time through a filter; distributing the filtered melt in different proportions through a distributor, passing it through a T-die, and then casting it on a non-mirror surface, followed by cooling and crystallization to form a film, wherein the casting speed is 50-100 m / min to obtain a pre-formed film; measuring and adjusting the thickness of the pre-formed film, and then traction and winding it into a film after surface corona treatment.

[0032] The performance of the cast polypropylene film provided by this invention was tested according to the following method:

[0033] (1) Haze, total light transmittance

[0034] The haze was measured using a Sanenshi YH1610 haze meter by means of transmitted light.

[0035] (2) Tensile properties

[0036] The tensile properties of the film were tested using a Shimadzu AGS-X series electronic universal testing machine.

[0037] (3) Dyne value

[0038] Using an Arcotest dyne pen, randomly select a dyne pen with a certain value and draw three lines on the film. If the lines do not shrink within 2 seconds, it indicates that the dyne value of the film is greater than or equal to that value. Select a dyne pen with a larger value for testing until the dyne pen shrinks within 2 seconds after drawing the lines. Stop the test and record the maximum value at which the dyne pen does not shrink. This value is the dyne value of the film.

[0039] (4) Electrolyte heat seal strength

[0040] Two 10cm x 10cm films were placed in a bottle containing electrolyte and baked at 85°C for 24 hours. After baking, the films were cleaned with alcohol, and then heat-sealed using a Tester Sangyo TP-701-B heat sealer at a temperature of 190°C, a pressure of 0.5 MPa, and a sealing time of 3 seconds. After the samples cooled to room temperature, the heat seal strength was tested using a Shimadzu AGS-X series electronic universal testing machine.

[0041] (5) Smoothness

[0042] The coefficient of friction between the films was measured using a Friction Tester HM-3 model from Toyo Seiki Co., Ltd. A lower coefficient of friction indicates better slip performance.

[0043] Example 1

[0044] This embodiment provides a cast polypropylene film, which includes a corona layer, a support layer, and a casting layer.

[0045] The corona layer resin was obtained by uniformly mixing 45 parts of ternary copolymer polypropylene resin TF400, 35 parts of homopolymer polypropylene resin FC801, 10 parts of silica-doped POE resin 3980FL (silica content 5%), 2026 parts of hyperbranched polyamide resin HyPer HPN, and 4 parts of slip masterbatch AB6018PP.

[0046] The support layer resin was obtained by uniformly mixing 180 parts of homopolymer polypropylene resin FC80, 10 parts of silica-doped POE resin 3980FL (silica content 5%), 2028 parts of hyperbranched polyamide resin HyPer HPN, and 2 parts of slip masterbatch AB6018PP.

[0047] The heat-sealing resin was obtained by uniformly mixing 85 parts of ternary copolymer polypropylene resin TF400, 5 parts of silica-doped POE resin 3980FL (silica content 5%), 2025 parts of hyperbranched polyamide resin HyPer HPN, and 5 parts of slip masterbatch AB6018PP.

[0048] After processing, each raw material is fed into a metering hopper and mixed in proportion. Then, it is fed into the corresponding extruder for pressurized melting and plasticizing to obtain a melt. The inlet temperature of extruders A, B, and C is controlled at 30°C, and the temperatures of zones 1, 2, and 3 are 200°C, 250°C, and 270°C, respectively.

[0049] The plasticized melt is filtered through a disc filter at a temperature of 250°C.

[0050] The filtered melt is distributed according to a ratio through a distributor, and then co-extruded through a three-layer T-die, cast at high speed, and cooled to crystallize into a film; the extrusion rate is 280 kg / h, the temperature of the distributor and the T-die is 270℃, and the casting speed is 50 m / min;

[0051] The thickness of the obtained film was measured, and then a corona discharge of 25 W / (m) was applied. 2 The corona layer surface is corona treated under conditions of 50 m / min, and then wound into a film by traction, with a winding width of 800-1300 mm and a winding speed of 50 m / min, to obtain the final product. The film thickness is 80 μm.

[0052] Example 2

[0053] As provided in Example 1, a cast polypropylene film.

[0054] The corona layer resin was obtained by uniformly mixing 46 parts of ternary copolymer polypropylene resin TF400, 140 parts of homopolymer polypropylene resin FC80, 5 parts of silica-doped POE resin 3980FL (silica content 5%), 2028 parts of hyperbranched polyamide resin HyPer HPN, and 1 part of slip masterbatch AB6018PP.

[0055] The support layer resin was obtained by uniformly mixing 5 parts of homopolymer polypropylene resin FC8018, 6 parts of silica-doped POE resin 3980FL (silica content 5%), 2024 parts of hyperbranched polyamide resin HyPer HPN, and 5 parts of slip masterbatch AB6018PP.

[0056] The heat-sealing resin was obtained by uniformly mixing 90 parts of ternary copolymer polypropylene resin TF400, 6 parts of silica-doped POE resin 3980FL (silica content 5%), 2022 parts of hyperbranched polyamide resin HyPer HPN, and 2 parts of slip masterbatch AB6018PP.

[0057] After processing, each raw material is fed into a metering hopper and mixed in proportion. Then, it is fed into the corresponding extruder for pressurized melting and plasticizing to obtain a melt. The feed inlet temperature of extruders 1, 2 and 3 is controlled at 35°C, and the temperatures of zones 1, 2 and 3 are 200°C, 250°C and 270°C, respectively.

[0058] The plasticized melt is filtered through a disc filter at a temperature of 250°C.

[0059] The filtered melt is distributed according to a ratio through a distributor, and then co-extruded through a three-layer T-die, cast at high speed, and cooled to crystallize into a film; the extrusion rate is 280 kg / h, the temperature of the distributor and the T-die is 270℃, and the casting speed is 50 m / min;

[0060] The thickness of the obtained film was measured, and then a corona discharge of 25 W / (m) was applied. 2 The corona layer surface is corona treated under conditions of 50 m / min, and then wound into a film by traction, with a winding width of 800-1300 mm and a winding speed of 50 m / min, to obtain the final product. The film thickness is 30 μm.

[0061] Example 3

[0062] As provided in Example 1, a cast polypropylene film.

[0063] The corona layer resin was obtained by uniformly mixing 50 parts of ternary copolymer polypropylene resin TF400, 30 parts of homopolymer polypropylene resin FC801, 13 parts of silica-doped POE resin 3980FL (silica content 5%), 22 parts of hyperbranched polyamide resin HyPer HPN 2022, and 5 parts of slip masterbatch AB6018PP.

[0064] The support layer resin was obtained by uniformly mixing 175 parts of homopolymer polypropylene resin FC80, 10 parts of silica-doped POE resin 3980FL (silica content 5%), 2028 parts of hyperbranched polyamide resin HyPer HPN, and 7 parts of slip masterbatch AB6018PP.

[0065] One part of ternary copolymer polypropylene resin TF4008, 10 parts of silica-doped POE resin 3980FL (silica content 5%), 2028 parts of hyperbranched polyamide resin HyPer HPN, and 1 part of slip masterbatch AB6018PP were uniformly mixed to obtain the heat-sealing layer resin.

[0066] After processing, each raw material is fed into a metering hopper and mixed in proportion. Then, it is fed into the corresponding extruder for pressurized melting and plasticizing to obtain a melt. The feed inlet temperature of extruders 1, 2 and 3 is controlled at 35°C, and the temperatures of zones 1, 2 and 3 are 200°C, 250°C and 270°C, respectively.

[0067] The plasticized melt is filtered through a disc filter at a temperature of 250°C.

[0068] The filtered melt is distributed according to a ratio through a distributor, and then co-extruded through a three-layer T-die, cast at high speed, and cooled to crystallize into a film; the extrusion rate is 280 kg / h, the temperature of the distributor and the T-die is 270℃, and the casting speed is 50 m / min;

[0069] The thickness of the obtained film was measured, and then a corona discharge of 25 W / (m) was applied. 2 The corona layer surface is corona treated under conditions of 50 m / min, and then wound into a film by traction, with a winding width of 800-1300 mm and a winding speed of 50 m / min, to obtain the final product. The film thickness is 90 μm.

[0070] Example 4

[0071] As provided in Example 1, a cast polypropylene film.

[0072] The corona layer resin was obtained by uniformly mixing 40 parts of ternary copolymer polypropylene resin TF400, 140 parts of homopolymer polypropylene resin FC80, 15 parts of silica-doped POE resin 3980FL (silica content 5%), 2023 parts of hyperbranched polyamide resin HyPer HPN, and 2 parts of slip masterbatch AB6018PP.

[0073] The support layer resin was obtained by uniformly mixing 5 parts of homopolymer polypropylene resin FC8018, 5 parts of silica-doped POE resin 3980FL (silica content 5%), 2025 parts of hyperbranched polyamide resin HyPer HPN, and 5 parts of slip masterbatch AB6018PP.

[0074] The heat-sealing resin was obtained by uniformly mixing 80 parts of ternary copolymer polypropylene resin TF400, 7 parts of silica-doped POE resin 3980FL (silica content 5%), 2028 parts of hyperbranched polyamide resin HyPer HPN, and 5 parts of slip masterbatch AB6018PP.

[0075] After processing, each raw material is fed into a metering hopper and mixed in proportion. Then, it is fed into the corresponding extruder for pressurized melting and plasticizing to obtain a melt. The feed inlet temperature of extruders 1, 2 and 3 is controlled at 35°C, and the temperatures of zones 1, 2 and 3 are 200°C, 250°C and 270°C, respectively.

[0076] The plasticized melt is filtered through a disc filter at a temperature of 250°C.

[0077] The filtered melt is distributed according to a ratio through a distributor, and then co-extruded through a three-layer T-die, cast at high speed, and cooled to crystallize into a film; the extrusion rate is 280 kg / h, the temperature of the distributor and the T-die is 270℃, and the casting speed is 50 m / min;

[0078] The thickness of the obtained film was measured, and then a corona discharge of 25 W / (m) was applied. 2The corona layer surface is corona treated under conditions of 50 m / min, and then wound into a film by traction, with a winding width of 800-1300 mm and a winding speed of 50 m / min, to obtain the final product. The film thickness is 70 μm.

[0079] Example 5

[0080] As provided in Example 1, a cast polypropylene film.

[0081] The corona layer resin was obtained by uniformly mixing 45 parts of ternary copolymer polypropylene resin TF400, 37 parts of homopolymer polypropylene resin FC801, 8 parts of silica-doped POE resin 3980FL (silica content 5%), 2026 parts of hyperbranched polyamide resin HyPer HPN, and 4 parts of slip masterbatch AB6018PP.

[0082] The support layer resin was obtained by uniformly mixing 2 parts of homopolymer polypropylene resin FC8018, 9 parts of silica-doped POE resin 3980FL (silica content 5%), 2028 parts of hyperbranched polyamide resin HyPer HPN, and 1 part of slip masterbatch AB6018PP.

[0083] The heat-sealing resin was obtained by uniformly mixing 88 parts of ternary copolymer polypropylene resin TF400, 5 parts of silica-doped POE resin 3980FL (silica content 5%), 2023 parts of hyperbranched polyamide resin HyPer HPN, and 4 parts of slip masterbatch AB6018PP.

[0084] After processing, each raw material is fed into a metering hopper and mixed in proportion. Then, it is fed into the corresponding extruder for pressurized melting and plasticizing to obtain a melt. The feed inlet temperature of extruders 1, 2 and 3 is controlled at 35°C, and the temperatures of zones 1, 2 and 3 are 200°C, 250°C and 270°C, respectively.

[0085] The plasticized melt is filtered through a disc filter at a temperature of 250°C.

[0086] The filtered melt is distributed according to a ratio through a distributor, and then co-extruded through a three-layer T-die, cast at high speed, and cooled to crystallize into a film; the extrusion rate is 280 kg / h, the temperature of the distributor and the T-die is 270℃, and the casting speed is 50 m / min;

[0087] The thickness of the obtained film was measured, and then a corona discharge of 25 W / (m) was applied. 2 The corona layer surface is corona treated under conditions of 50 m / min, and then wound into a film by traction, with a winding width of 800-1300 mm and a winding speed of 50 m / min, to obtain the final product. The film thickness is 40 μm.

[0088] Comparative Example 1

[0089] A cast polypropylene film is provided.

[0090] The corona layer resin was obtained by uniformly mixing 45 parts of ternary copolymer polypropylene resin TF400, 145 parts of homopolymer polypropylene resin FC80, 2026 parts of hyperbranched polyamide resin HyPer HPN, and 4 parts of slip masterbatch AB6018PP.

[0091] One part of homopolymer polypropylene resin FC8019, one part of hyperbranched polyamide resin HyPer HPN 2028, and one part of slip masterbatch AB6018PP were uniformly mixed to obtain the support layer resin.

[0092] The heat-sealing resin was obtained by uniformly mixing 93 parts of ternary copolymer polypropylene resin TF400, 23 parts of hyperbranched polyamide resin HyPer HPN, and 4 parts of slip masterbatch AB6018PP.

[0093] After processing, each raw material is fed into a metering hopper and mixed in proportion. Then, it is fed into the corresponding extruder for pressurized melting and plasticizing to obtain a melt. The feed inlet temperature of extruders 1, 2 and 3 is controlled at 35°C, and the temperatures of zones 1, 2 and 3 are 200°C, 250°C and 270°C, respectively.

[0094] The plasticized melt is filtered through a disc filter at a temperature of 250°C.

[0095] The filtered melt is distributed according to a ratio through a distributor, and then co-extruded through a three-layer T-die, cast at high speed, and cooled to crystallize into a film; the extrusion rate is 280 kg / h, the temperature of the distributor and the T-die is 270℃, and the casting speed is 50 m / min;

[0096] The thickness of the obtained film was measured, and then a corona discharge of 25 W / (m) was applied. 2 The corona layer surface is corona treated under conditions of 50 m / min, and then wound into a film by traction, with a winding width of 800-1300 mm and a winding speed of 50 m / min, to obtain the final product. The film thickness is 60 μm.

[0097] Compared with the technical solution provided by the present invention, the difference of the cast polypropylene film provided in Comparative Example 1 is that no silica-doped POE resin is added in the formulation.

[0098] Comparative Example 2

[0099] A cast polypropylene film is provided.

[0100] The corona layer resin was obtained by uniformly mixing 45 parts of ternary copolymer polypropylene resin TF400, 43 parts of homopolymer polypropylene resin FC801, 8 parts of silica-doped POE resin 3980FL (silica content 5%), and 4 parts of slip masterbatch AB6018PP.

[0101] The support layer resin was obtained by uniformly mixing 190 parts of homopolymer polypropylene resin FC80, 9 parts of silica-doped POE resin 3980FL (silica content 5%), and 1 part of slip masterbatch AB6018PP.

[0102] The heat-sealing resin was obtained by uniformly mixing 1 part of ternary copolymer polypropylene resin TF4009, 5 parts of silica-doped POE resin 3980FL (silica content 5%), and 4 parts of slip masterbatch AB6018PP.

[0103] After processing, each raw material is fed into a metering hopper and mixed in proportion. Then, it is fed into the corresponding extruder for pressurized melting and plasticizing to obtain a melt. The feed inlet temperature of extruders 1, 2 and 3 is controlled at 35°C, and the temperatures of zones 1, 2 and 3 are 200°C, 250°C and 270°C, respectively.

[0104] The plasticized melt is filtered through a disc filter at a temperature of 250°C.

[0105] The filtered melt is distributed according to a ratio through a distributor, and then co-extruded through a three-layer T-die, cast at high speed, and cooled to crystallize into a film; the extrusion rate is 280 kg / h, the temperature of the distributor and the T-die is 270℃, and the casting speed is 50 m / min;

[0106] The thickness of the obtained film was measured, and then a corona discharge of 25 W / (m) was applied. 2 The corona layer surface is corona treated under conditions of 50 m / min, and then wound into a film by traction, with a winding width of 800-1300 mm and a winding speed of 50 m / min, to obtain the final product. The film thickness is 60 μm.

[0107] Compared with the technical solution provided by the present invention, the difference of the cast polypropylene film provided in Comparative Example 1 is that the hyperbranched polyamide resin HyPer HPN 202 is not added to the formulation.

[0108] Table 1. Performance test results of the polypropylene films provided in Examples 1-5 and Comparative Examples 1-2

[0109]

[0110]

[0111] Specifically, as shown in Table 1, when no silica-doped POE resin was added in Comparative Example 1, the crystallinity of the corona layer could not be reduced. Therefore, the friction coefficient was high due to the influence of polarity, and the extensibility of the support layer was also reduced. That is, the combination of silica-doped POE resin with other materials ensured the overall performance of the cast polypropylene film. The film was greatly affected in the absence of silica-doped POE resin.

[0112] Specifically, as shown in Table 1, when the hyperbranched polyamide resin HyPer HPN 202 was not added in Comparative Example 2, the ductility of the support layer was also affected, and the heat-sealing layer lacked the addition of the hyperbranched polyamide resin HyPer HPN 202, resulting in a significant decrease in heat-sealing strength, i.e., a decrease in bonding performance.

[0113] In summary, this paper describes a cast polypropylene film for aluminum-plastic composite film and its preparation method. Different types of polypropylene are used as the main material, with different auxiliary materials added to prepare the corona layer, support layer, and heat-sealing layer, which are then integrally formed using a three-layer co-extrusion technology. The corona layer is mainly composed of ternary copolymer polypropylene resin, supplemented by polypropylene homopolymer. The addition of silica-doped POE resin reduces the crystallinity of the corona layer after film formation. This decrease in crystallinity leads to an increase in the polarity of the corona layer during corona treatment, which is beneficial for... The CPP film is composed of materials such as aluminum foil. The support layer is mainly composed of polypropylene homopolymer, supplemented by hyperbranched resin and silica-doped POE resin. The addition of a small amount of inorganic materials can improve the stiffness of the CPP film, while the addition of hyperbranched resin and POE resin enhances the ductility of the CPP film. The heat-sealing layer is mainly composed of ternary copolymer polypropylene, with the addition of some silica-doped POE resin and hyperbranched polyester. The addition of inorganic materials in the heat-sealing layer can increase the residual rate of the heat-sealing layer during heat sealing of CPP material, and improve the heat-sealing strength and electrolyte resistance.

[0114] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A cast polypropylene film for aluminum-plastic film, characterized in that, include: The corona layer, support layer, and heat-sealing layer are co-extruded by melt. in The raw materials of the corona layer include the main material ternary copolymer polypropylene resin and the auxiliary materials homopolymer polypropylene resin, silica-doped POE resin and hyperbranched polyamide resin. The raw materials for the support layer include homopolymer polypropylene resin as the main material and silica-doped POE resin and hyperbranched polyamide resin as auxiliary materials. The raw materials for the heat-sealing layer include the main material ternary copolymer polypropylene resin and the auxiliary materials silica-doped POE resin and hyperbranched polyamide resin.

2. The cast polypropylene film for aluminum-plastic film as described in claim 1, characterized in that, The corona layer comprises the following components by mass parts: 40-50 parts of ternary copolymer polypropylene resin, 30-40 parts of homopolymer polypropylene resin, 5-15 parts of silica-doped POE resin, 2-8 parts of hyperbranched polyamide resin, and 1-5 parts of slip masterbatch.

3. The cast polypropylene film for aluminum-plastic film as described in claim 1, characterized in that, The support layer comprises the following components by mass parts: 75-85 parts homopolymer polypropylene resin, 5-10 parts silica-doped POE resin, 2-8 parts hyperbranched polyamide resin, and 1-7 parts slip masterbatch.

4. The cast polypropylene film for aluminum-plastic film as described in claim 1, characterized in that, The heat-sealing layer comprises the following components by mass parts: 80-90 parts of ternary copolymer polypropylene resin, 5-10 parts of silica-doped POE resin, 2-8 parts of hyperbranched amide resin, and 1-5 parts of slip masterbatch.

5. The cast polypropylene film for aluminum-plastic film as described in claim 1, characterized in that, The melt flow rate of the ternary copolymer polypropylene resin is 6-8 g / 10 min.

6. The cast polypropylene film for aluminum-plastic film as described in claim 1, characterized in that, The silica doping content in the silica-doped POE resin is 3-10%.

7. The cast polypropylene film for aluminum-plastic film as described in claim 1, characterized in that, The melt flow rate of the homopolymer polypropylene resin is 16-18 g / 10min.

8. The cast polypropylene film for aluminum-plastic film as described in claim 1, characterized in that, The thickness ratio of the corona layer, the support layer, and the heat-sealing layer is (1-1.5):(2-3):(1-1.5); and The thickness of the cast polypropylene film used for the aluminum-plastic film is 30-90 μm.

9. A method for preparing a cast polypropylene film for aluminum-plastic film as described in any one of claims 1-8, characterized in that, Includes the following steps: After mixing all the raw materials evenly in proportion, clean and metered feeding is carried out. Set the temperature of the melt extruder, filter, and transmission pipeline to 220-270℃, and the temperature of the distributor and T-die to 260-280℃; The mixed materials are melted, sheared, and plasticized by passing them through different extruder screws to obtain a melt; The melt is filtered a second time through a filter; The filtered melt is distributed in different proportions through a distributor, passes through a T-die and is then cast in a non-mirror finish, cooled and crystallized, and shaped into a film. The casting speed is 50-100 m / min to obtain a pre-formed film. The pre-made film is measured and its thickness is adjusted. After surface corona treatment, it is wound into a film by traction.

10. An aluminum-plastic film, characterized in that, The cast polypropylene film for aluminum-plastic film as described in any one of claims 1-8 is used.

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