WO2024104393A1 - Multilayer composite polypropylene material, and preparation method therefor and use thereof - Google Patents

Multilayer composite polypropylene material, and preparation method therefor and use thereof Download PDF

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Publication number
WO2024104393A1
WO2024104393A1 PCT/CN2023/131848 CN2023131848W WO2024104393A1 WO 2024104393 A1 WO2024104393 A1 WO 2024104393A1 CN 2023131848 W CN2023131848 W CN 2023131848W WO 2024104393 A1 WO2024104393 A1 WO 2024104393A1
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Prior art keywords
polypropylene
modified
layer
composite
polypropylene material
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PCT/CN2023/131848
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French (fr)
Chinese (zh)
Inventor
朱中亚
王帅
夏建中
李学法
张国平
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扬州纳力新材料科技有限公司
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Publication of WO2024104393A1 publication Critical patent/WO2024104393A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D7/00—Producing flat articles, e.g. films or sheets
    • B29D7/01—Films or sheets
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
    • B32B27/20—Layered products comprising a layer of synthetic resin characterised by the use of special additives using fillers, pigments, thixotroping agents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films or sheets
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/49—Phosphorus-containing compounds
    • C08K5/51—Phosphorus bound to oxygen
    • C08K5/52—Phosphorus bound to oxygen only
    • C08K5/524—Esters of phosphorous acids, e.g. of H3PO3
    • C08K5/526—Esters of phosphorous acids, e.g. of H3PO3 with hydroxyaryl compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
    • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
    • C08L23/10—Homopolymers or copolymers of propene
    • C08L23/12—Polypropene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L51/00—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
    • C08L51/06—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers grafted on to homopolymers or copolymers of aliphatic hydrocarbons containing only one carbon-to-carbon double bond

Definitions

  • the invention relates to the technical field of composite materials, in particular to a multi-layer composite polypropylene material and a preparation method and application thereof.
  • composite current collectors based on polymer films have received widespread attention and application in the new energy industry.
  • the preparation process of the composite current collector is usually: a layer of metal (aluminum, copper, etc.) material is deposited on a polymer film (such as polypropylene, polyethylene, polyester, etc.) by physical vapor deposition (PVD).
  • PVD physical vapor deposition
  • the prepared surface metallized film with a certain conductivity is the composite current collector.
  • composite current collectors based on polymer films have the advantages of low cost, light weight and good internal insulation. These advantages enable the composite current collector to reduce the cost of the battery and improve the energy density and safety of the battery when used in the battery.
  • composite current collectors based on polypropylene films are more common.
  • the process of preparing composite current collectors with traditional polypropylene films as base films due to the weak polarity of the polypropylene film itself, its surface tension is low, and the affinity between the polypropylene film with low surface tension and the metal layer with high surface tension is poor, which leads to low adhesion between the interface of the two and weak bonding, that is, there is a problem of poor surface adhesion performance.
  • the method of corona treatment on the surface of polypropylene film is usually adopted to increase the surface tension of the film, thereby improving the bonding firmness between the polypropylene film and the metal material, but this method has the following shortcomings: the surface tension of the polymer film after corona treatment is unstable. After being stored for a period of time, the surface tension decreases and finally approaches the surface tension of the polymer film before treatment, that is, there is a problem of unstable storage.
  • a multilayer composite polypropylene material which has high surface tension and good storage stability, strong affinity with metals, and can be firmly combined with metals. It can be used to prepare a composite current collector and further used in pole pieces or batteries.
  • a multi-layer composite polypropylene material the structure of which comprises a first modified layer, a core layer and a second modified layer which are stacked;
  • the first modified layer includes a first modified polypropylene
  • the core layer comprises polypropylene
  • the second modified layer includes a second modified polypropylene
  • the first modified polypropylene and the second modified polypropylene are independently selected from one or more of small molecule graft-modified polypropylene and oligomer graft-modified polypropylene.
  • the polypropylene in the core layer is unmodified polypropylene.
  • the polypropylene in the core layer does not comprise modified polypropylene.
  • the small molecule grafted modified polypropylene includes: maleic anhydride grafted modified polypropylene, acrylic acid-maleic anhydride grafted modified polypropylene, diethylenetriamine-methacrylate glycidyl grafted modified polypropylene, acrylamide grafted modified polypropylene, acrylamide-acrylic acid grafted modified polypropylene, succinic anhydride grafted polypropylene, succinylfluorescein-succinic anhydride grafted polypropylene and one or more of modified polypropylenes in which hydrogen in the polar modified molecules is replaced by methyl, ethyl or halogen atoms.
  • the oligomer grafted modified polypropylene includes: polypropylene grafted with maleic anhydride oligomer, polypropylene grafted with (acrylic acid-maleic anhydride) oligomer, polypropylene grafted with di(ethylenetriamine-glycidyl methacrylate) oligomer, polypropylene grafted with acrylamide oligomer, polypropylene grafted with (acrylamide-acrylic acid) oligomer, polypropylene grafted with succinic anhydride oligomer, and polypropylene grafted with (succinyl) anhydride oligomer.
  • the polymerization degree of the oligomer is 2-20, preferably 5-10. Too high polymerization degree of the oligomer is easy to form defects in the modified layer.
  • the combination of small molecule grafted modified polypropylene and oligomer grafted modified polypropylene is preferred.
  • the grafting ratio g of the first modified polypropylene and the second modified polypropylene satisfies: 0.1% ⁇ g ⁇ 2%.
  • the first modified polypropylene has a melt index of about (3.1-4.1) g/10 min/(230° C./2.16 kg) and a molecular weight distribution index of about 4.5-5.6.
  • the melt index of the second modified polypropylene is about (3.2-4.0) g/10 min/(230° C./2.16 kg), and the molecular weight distribution index is about 4.5-5.6.
  • the polypropylene in the core layer is unmodified polypropylene, and the melt index of the polypropylene is about (3.0-3.9) g/10 min/(230° C./2.16 kg), the molecular weight distribution index is about 4.5-5.2, and the isotacticity is about ⁇ 97%.
  • the mass percentage of the first modified polypropylene is about ⁇ 20%.
  • the first modified layer further includes a first polypropylene and a first antioxidant
  • the first modified layer includes about 0%-79.8% of the first polypropylene, about 20%-99.9% of the first modified polypropylene and about 0.1%-0.6% of the first antioxidant.
  • the first polypropylene has a melt index of about (3.0-3.9) g/10 min/(230° C./2.16 kg), a molecular weight distribution index of about 4.5-5.2, and an isotacticity of about 89%-97%.
  • the first antioxidant is selected from one or more of triphenyl phosphite, butylated hydroxyanisole, 2,6-di-tert-butyl-4-methylphenol, and p-tert-butylcatechol.
  • the mass percentage of the second modified polypropylene is The content is approximately ⁇ 20%.
  • the second modified layer further includes a second polypropylene and a second antioxidant
  • the second modified layer includes about 0%-79.8% of the second polypropylene, about 20%-99.9% of the second modified polypropylene and about 0.1%-0.6% of the second antioxidant.
  • the second polypropylene has a melt index of about (3.0-3.9) g/10 min/(230° C./2.16 kg), a molecular weight distribution index of about 4.5-5.2, and an isotacticity of about 89%-97%.
  • the difference between the isotacticity of the first polypropylene and the isotacticity of the polypropylene in the core layer is about 1%-8%, preferably 2%-8%.
  • the second antioxidant is selected from one or more of triphenyl phosphite, butylated hydroxyanisole, 2,6-di-tert-butyl-4-methylphenol and p-tert-butylcatechol.
  • the core layer further comprises a third antioxidant
  • the core layer includes about 99.5%-99.8% of the polypropylene and about 0.2%-0.5% of the third antioxidant.
  • the core layer is composed of unmodified polypropylene and a third antioxidant
  • the core layer includes about 99.5%-99.8% of the polypropylene and about 0.2%-0.5% of the third antioxidant.
  • the third antioxidant is selected from one or more of triphenyl phosphite, butylated hydroxyanisole, 2,6-di-tert-butyl-4-methylphenol, and p-tert-butylcatechol.
  • the thickness of the multi-layer composite polypropylene material is about ⁇ 1 ⁇ m, wherein the thickness of the first modified layer and the second modified layer account for about 5%-15% respectively, and the thickness of the core layer accounts for about 70%-90%.
  • the present application also provides a method for preparing the multi-layer composite polypropylene material as described above.
  • the technical solution is as follows:
  • a method for preparing the multilayer composite polypropylene material as described above comprises the following steps:
  • the first modified layer intermediate, the core layer intermediate and the second modified layer intermediate are composite-molded by a sheet-making process at about 15-60° C. to prepare a multi-layer composite polypropylene material intermediate;
  • the multi-layer composite polypropylene material intermediate is subjected to synchronous stretching treatment to prepare the multi-layer composite polypropylene material, and the total longitudinal stretching ratio is about 5-9 times and the total transverse stretching ratio is about 4-8 times.
  • the synchronous stretching comprises the following steps:
  • the raw material comprising the second modified polypropylene is melted at about 200-260° C., Extrusion at 230-260° C. to prepare a second modified layer intermediate;
  • the first modified layer intermediate, the core layer intermediate and the second modified layer intermediate are composite-molded by a sheet-making process at about 15-60° C. to prepare a multi-layer composite polypropylene material intermediate;
  • the multi-layer composite polypropylene material intermediate is subjected to asynchronous stretching treatment to prepare the multi-layer composite polypropylene material, and the total longitudinal stretching ratio is about 5-9 times and the total transverse stretching ratio is about 4-8 times.
  • the asynchronous stretching comprises the following steps:
  • thermoforming treatment on the multi-layer composite polypropylene material III at a temperature of about 165-170° C. to prepare a multi-layer composite polypropylene material IV;
  • the multi-layer composite polypropylene material IV is heat-treated at about 120-135° C. to prepare the multi-layer composite polypropylene material.
  • the present application also provides a composite current collector, the structure of which includes a first protective layer, a first metal layer, a support layer, a second metal layer and a second protective layer arranged in layers;
  • the support layer comprises a composite polypropylene material according to above.
  • the first protective layer and the second protective layer independently include: one or more of an inactive metal and its alloy, a metal oxide and a carbon material;
  • the first metal layer and the second metal layer independently include metals and alloys thereof with a resistivity of about ⁇ 8 ⁇ 10-8 ⁇ m.
  • the inactive metal is selected from nickel and/or chromium.
  • the inactive metal alloy is selected from one or more of a nickel-based alloy, a chromium-based alloy, and a nickel-chromium-copper alloy.
  • the metal oxide is selected from copper oxide.
  • the carbon material is selected from one or more of aluminum oxide, nickel oxide, chromium oxide, cobalt oxide and copper chromium oxide.
  • the carbon material is selected from one or more of graphite, carbon black, acetylene black, Ketjen black, carbon nano quantum dots, carbon nanotubes, carbon nanofibers and graphene.
  • the metal with a resistivity of about ⁇ 8 ⁇ 10-8 ⁇ m is selected from one or more of copper, aluminum, silver, gold, zinc, molybdenum, cobalt, and nickel, and the alloy that meets the requirements is selected from one or more of copper alloys, aluminum alloys, and nickel alloys.
  • the present application also provides a pole piece, comprising the composite current collector as described above.
  • the present application also provides a battery, comprising the pole piece as described above.
  • FIG1 is a schematic diagram of the structure of a multilayer composite polypropylene material provided according to one or more embodiments
  • FIG2 is a flow chart of a method for preparing a multilayer composite polypropylene material according to one or more embodiments
  • FIG3 is a flow chart of a method for preparing a multilayer composite polypropylene material according to one or more embodiments
  • FIG4 is a schematic diagram of the structure of a composite current collector according to one or more embodiments.
  • FIG5 is a schematic diagram showing the result of measuring energy density varying with cycle number when the composite current collector sample provided according to one or more embodiments is an electrode current collector of a battery.
  • the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.
  • any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, and any upper limit can be combined with any other upper limit to form an unspecified range.
  • each separately disclosed point or single value can itself be combined as a lower limit or upper limit with any other point or single value or with other lower limits or upper limits to form an unspecified range.
  • the temperature parameters in the present invention allow both constant temperature treatment and treatment within a certain temperature range.
  • the constant temperature treatment allows the temperature to be within the precision range controlled by the instrument. fluctuation.
  • the unit of the data range when it comes to the unit of the data range, if there is a unit only after the right endpoint, it means that the units of the left endpoint and the right endpoint are the same.
  • 150-160°C means that the units of the left endpoint "150” and the right endpoint "160” are both °C (degrees Celsius).
  • first and second are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as “first” and “second” may explicitly or implicitly include at least one of the features.
  • the meaning of “multiple” is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.
  • severeal is at least one, such as one, two, etc., unless otherwise clearly and specifically defined.
  • the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially.
  • the method may further include step (c), which means that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.
  • the grafting ratio refers to the ratio of the mass of the polar monomer grafted onto the polypropylene to the mass of the grafted polypropylene.
  • the isotacticity is obtained by testing according to GB/T 2412-2008 standard.
  • the transverse stretch ratio refers to the elongation multiple of the stretched material in the transverse direction (or width) relative to the unstretched material
  • the longitudinal stretch ratio refers to the elongation multiple of the stretched material in the longitudinal direction (or length) relative to the unstretched material
  • the composite current collector based on polypropylene film has the characteristics of low cost, light weight, and good internal insulation, the material polarity of the polypropylene film itself is weak, resulting in low surface tension.
  • the affinity between the low surface tension polypropylene film and the high surface tension metal layer is poor, which causes adhesion between the two interfaces.
  • the force is low and the bonding is not strong, that is, there is a problem of poor surface adhesion and unstable surface tension.
  • the present invention provides a multi-layer composite polypropylene material which has high surface tension, good storage stability, strong affinity with metals, and can be firmly bonded together.
  • a multi-layer composite polypropylene material the structure of which comprises a first modified layer, a core layer and a second modified layer which are stacked;
  • the first modified layer includes a first modified polypropylene
  • the core layer comprises polypropylene
  • the second modified layer includes a second modified polypropylene
  • the first modified polypropylene and the second modified polypropylene are independently selected from:
  • Small molecule grafted modified polypropylene one or more of maleic anhydride grafted modified polypropylene, acrylic acid-maleic anhydride grafted modified polypropylene, diethylenetriamine-glycidyl methacrylate grafted modified polypropylene, acrylamide grafted modified polypropylene, acrylamide-acrylic acid grafted modified polypropylene, succinic anhydride grafted polypropylene, succinylfluorescein-succinic anhydride grafted polypropylene and modified polypropylene in which hydrogen in the polar modified molecule is replaced by methyl, ethyl or halogen atoms;
  • Oligomer grafted polypropylene polypropylene grafted with maleic anhydride oligomers, polypropylene grafted with (acrylic acid-maleic anhydride) oligomers, polypropylene grafted with glycidyl methacrylate oligomers, polypropylene grafted with di(ethylenetriamine-glycidyl methacrylate) oligomers, polypropylene grafted with acrylamide oligomers, (acrylamide-acrylic acid) oligomers, succinic anhydride grafted polypropylene, (succinylfluorescein-succinic anhydride) oligomers, and one or more of modified polypropylenes in which hydrogen in the polar modified molecule is replaced by methyl, ethyl or halogen atoms.
  • the degree of polymerization of the oligomer is 2-20, preferably 5-10. Too high a polymerization degree of the oligomer is easy to cause polymerization in the modified
  • the composition of small molecule graft-modified polypropylene and oligomer graft-modified polypropylene is preferred.
  • polypropylene modified by polar molecules Compared with unmodified polypropylene, polypropylene modified by polar molecules has greater polarity and surface tension.
  • the present invention effectively improves the surface polarity of the composite polypropylene material and thus improves its surface tension by adding polypropylene modified by polar molecules to the surface layer of the multilayer composite polypropylene material, while ensuring that the tensile strength of the multilayer composite polypropylene material meets the performance requirements of the current collector.
  • the polypropylene modified by polar molecules is not easy to crystallize, and can inhibit the crystallization of polypropylene and increase the free volume.
  • the surface adhesion performance of the composite polypropylene material is jointly promoted by the increase of the surface tension and free volume of the modified layer (surface layer), and the metal bonding force is strong, and it can be firmly combined with the metal.
  • the polar molecules and polypropylene in the modified polypropylene are connected by covalent bonds, the structure is stable, so that the surface tension of the surface layer is stable, and the surface tension will not decay during the storage process, showing excellent storage stability. Therefore, if the composite polypropylene material prepared in this application is used as the substrate of the composite current collector, it can be firmly bonded to the metal layer to improve the battery performance.
  • FIG1 is a schematic diagram of the structure of a composite polypropylene material prepared according to one embodiment of the present invention, wherein 101 represents a first modified layer, 102 represents a core layer, and 103 represents a second modified layer.
  • first modified layer and the second modified layer have the same function, but the material types and contents in the first modified layer and the second modified layer can be the same or different.
  • the core layer does not contain modified polypropylene.
  • the inventors of the present invention have found that the core layer does not contain modified polypropylene, which can ensure that the multi-layer composite polypropylene material meets the mechanical property requirements of the composite current collector, such as tensile strength.
  • the first modified polypropylene and the second modified polypropylene modified by polar molecules are independently selected from: polypropylene grafted with maleic anhydride, polypropylene grafted with acrylic acid and maleic anhydride, polypropylene grafted with diethylenetriamine and glycidyl methacrylate, polypropylene grafted with acrylamide, One or more of modified polypropylene, acrylamide-acrylic acid grafted modified polypropylene, succinic anhydride grafted polypropylene, succinylfluorescein-succinic anhydride grafted polypropylene, and modified polypropylene in which hydrogen in polar modified molecules is replaced by methyl, ethyl or halogen atoms, maleic anhydride oligomer grafted modified polypropylene, (acrylic acid-maleic anhydride) oligomer grafted modified polypropylene, methacrylate glycidyl oligomer grafted modified poly
  • modified polypropylene can better improve the polarity of polypropylene, improve surface tension and storage stability. It can be understood that, in the present invention, the types of the first modified polypropylene and the second modified polypropylene can be the same or different.
  • the inventors of the present invention have found that the increase in the content of polar molecules in the polypropylene molecules can cause the surface tension of the first modified layer and the second modified layer to show an increasing trend; polar molecules in the polypropylene molecules play a role in disrupting the regularity of molecular arrangement on the one hand, and on the other hand, they play a role in crystallization nucleation, and the two restrict each other and affect the free volume.
  • the grafting rate will also affect the film forming properties and surface defects of the material, and thus affect the yield rate. It can be understood that the grafting rates of the first modified polypropylene and the second modified polypropylene can be the same or different.
  • the grafting rates of the first modified polypropylene and the second modified polypropylene are both approximately ⁇ 0.1%, including but not limited to: 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5% or 1.6%.
  • the grafting rates of the first modified polypropylene and the second modified polypropylene are respectively about 0.2%-1.5%, which can synergistically improve the surface tension and free volume of the composite polypropylene, thereby improving its bonding strength with the metal.
  • the crystal area is reduced, thus affecting its physical properties such as hardness, strength and rigidity, resulting in defects in the modified layer. If the grafting rate is too low, the polarity, surface tension and free volume of the first modified layer or the second modified layer will be limited.
  • the inventors of the present invention have found that changing the melt index of the modified polypropylene in the first modified layer and/or the second modified layer can adjust the surface tension and free volume, film forming properties and mechanical properties of the modified layer. It is understandable that the melt index of the first modified polypropylene and the second modified polypropylene can be the same or different.
  • the melt index of the first modified polypropylene is about (3.1-4.1) g/10min/(230°C/2.16kg), including but not limited to 3.1 g/10min, 3.2 g/10min, 3.3 g/10min, 3.4 g/10min, 3.5 g/10min, 3.6 g/10min, 3.7 g/10min, 3.8 g/10min, 3.9 g/10min, 4.0 g/10min and 4.1 g/10min.
  • the melt index of the first modified polypropylene is about (3.2-4.0) g/10 min/(230°C/2.16 kg), which can synergistically improve the surface tension and free volume of the composite polypropylene, thereby improving its bonding strength with the metal, and ensuring the film forming property, yield rate and mechanical properties of the material.
  • the melt index of the second modified polypropylene is about (3.1-4.1) g/10min/(230°C/2.16kg), including but not limited to 3.1 g/10min, 3.2 g/10min, 3.3 g/10min, 3.4 g/10min, 3.5 g/10min, 3.6 g/10min, 3.7 g/10min, 3.8 g/10min, 3.9 g/10min, 4.0 g/10min and 4.1 g/10min.
  • the melt index of the second modified polypropylene is about (3.2-4.0) g/10 min/(230°C/2.16 kg), which can synergistically improve the surface tension and free volume of the composite polypropylene, thereby improving its bonding strength with the metal, and ensuring the film forming property, yield rate and mechanical properties of the material.
  • the inventors of the present invention have found that by changing the molecular weight distribution index of the modified polypropylene in the first modified layer and/or the second modified layer, the surface tension and free volume, as well as the film forming property, yield rate and mechanical properties of the modified layer can also be regulated. It can be understood that the molecular weight of the first modified polypropylene and the second modified polypropylene is The distribution indices can be the same or different.
  • the molecular weight distribution index of the first modified polypropylene is about 4.5-5.6, including but not limited to 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5 and 5.6.
  • the molecular weight distribution index of the first modified polypropylene is about 4.6-5.5, which can synergistically improve the surface tension and free volume of the composite polypropylene, thereby improving its bonding strength with the metal, and ensuring the film forming property, yield rate and mechanical properties of the material.
  • the molecular weight distribution index of the second modified polypropylene is about 4.5-5.6, including but not limited to 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5 and 5.6.
  • the molecular weight distribution index of the second modified polypropylene is about 4.6-5.5, which can synergistically improve the surface tension and free volume of the composite polypropylene, thereby improving its bonding strength with the metal, and ensuring the film forming property, yield rate and mechanical properties of the material.
  • adding modified polypropylene grafted with polar molecules to the modified layer can increase the polarity of the modified layer.
  • the inventors of the present invention have found that changing the content of modified polypropylene in the first modified layer and the second modified layer can adjust the surface tension and free volume of the modified layer, as well as the film forming property, yield rate and mechanical properties of the material.
  • the mass percentage of the first modified polypropylene is about ⁇ 20%, including but not limited to 20%, 22%, 23%, 24%, 25%, 26%, 28%, 30%, 32%, 33%, 34%, 36%, 38%, 40%, 41%, 42%, 44%, 45%, 46%, 48%, 50%, 51%, 52%, 55%, 58%, 60%, 62%, 65%, 70%, 72%, 75%, 80%, 85%, 88%, 90%, 92%, 95%, 96%, 98%, 99.8%, 99% and 100%.
  • the first modified layer further includes a first polypropylene and a first antioxidant.
  • the film forming property, yield rate and mechanical properties of the composite polypropylene material are improved through the action of the polypropylene and the antioxidant.
  • the melt index of the first polypropylene is about (3.0-3.9) g/10 min/(230°C/2.16 kg), including but not limited to 3.0 g/10 min, 3.1 g/10 min, 3.2 g/10 min, 3.3 g/10 min, 3.4 g/10 min, 3.5 g/10 min, 3.6 g/10 min, 3.7 g/10 min, 3.8 g/10 min and 3.9 g/10 min.
  • the molecular weight distribution index of the first polypropylene is about 4.5-5.2, including but not limited to 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1 and 5.2.
  • the inventors of the present invention have found that the isotacticity of polypropylene affects the regularity of the arrangement of the polymer in the modified layer, further affecting the free volume, binding force and adhesion performance, and also affects the mechanical properties and film-forming properties of the composite polypropylene material.
  • the isotacticity of the first polypropylene is about 89%-97%, including but not limited to 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96% and 97%.
  • the isotacticity of the first polypropylene is about 90%-96%, which can synergize the surface tension, free volume, mechanical properties, yield and film-forming properties of the composite polypropylene material.
  • the difference between the isotacticity of the first polypropylene described in the present invention and the isotacticity of the polypropylene is about 1%-8%, preferably 2%-8%, so that the first modified layer and the core layer can be gradually transitioned, which can not only avoid stress concentration problems and improve the overall strength and toughness of the multilayer structure, but also avoid the risk of interlayer delamination or cracking caused by interface stress caused by performance mismatch between adjacent layers.
  • the first antioxidant is selected from one or more of triphenyl phosphite, butylated hydroxyanisole, 2,6-di-tert-butyl-4-methylphenol, and p-tert-butylcatechol.
  • the first modified layer includes about 0%-79.8% of the first polypropylene, about 20%-99.9% of the first modified polypropylene, and about 1%-20% of the first antioxidant, based on mass percentage. 0.1%-0.6%.
  • the content of the first polypropylene includes but is not limited to 0%, 2%, 5%, 10%, 15%, 20%, 22%, 23%, 24%, 25%, 26%, 28%, 30%, 32%, 33%, 34%, 36%, 38%, 40%, 41%, 42%, 44%, 45%, 46%, 49.8%, 50%, 51%, 52%, 55%, 58%, 60%, 62%, 65%, 70%, 72%, 75% and 79.8%.
  • the first modified layer includes about 20%-50% of the first polypropylene.
  • the content of the first modified polypropylene includes but is not limited to 20%, 22%, 23%, 24%, 25%, 26%, 28%, 30%, 32%, 33%, 34%, 36%, 38%, 40%, 41%, 42%, 44%, 45%, 46%, 48%, 50%, 51%, 52%, 55%, 58%, 60%, 62%, 65%, 70%, 72%, 75%, 80%, 85%, 88%, 90%, 92%, 95%, 96%, 99.8% and 99.9%.
  • the first modified layer includes about 20%-99.8% of the first modified polypropylene.
  • the content of the first antioxidant includes, but is not limited to, 0.1%, 0.2%, 0.3%, 0.4%, 0.5% and 0.6%.
  • the first modified layer includes about 0.2%-0.5% of the first antioxidant in terms of mass percentage.
  • the first modified layer and the second modified layer have the same function, and the description of the second modified layer can refer to the first modified layer, as follows:
  • the mass percentage of the second modified polypropylene is about ⁇ 20%, including but not limited to 20%, 22%, 23%, 24%, 25%, 26%, 28%, 30%, 32%, 33%, 34%, 36%, 38%, 40%, 41%, 42%, 44%, 45%, 46%, 48%, 50%, 51%, 52%, 55%, 58%, 60%, 62%, 65%, 70%, 72%, 75%, 80%, 85%, 88%, 90%, 92%, 95%, 96%, 98%, 99.8%, 99% and 100%.
  • the mass percentage of the first modified polypropylene is about ⁇ 20%; and in the second modified layer, the mass percentage of the second modified polypropylene is about ⁇ 20%. This can better coordinate the surface tension, free volume, mechanical properties, yield and film-forming properties of the composite polypropylene material.
  • the second modified layer further includes a second polypropylene and a second antioxidant.
  • a second polypropylene and a second antioxidant Through the action of the polypropylene and the antioxidant, the film forming property, the yield rate and the mechanical properties of the composite polypropylene material are improved.
  • the melt index of the second polypropylene is about (3.0-3.9) g/10 min/(230°C/2.16 kg), including but not limited to 3.0 g/10 min, 3.1 g/10 min, 3.2 g/10 min, 3.3 g/10 min, 3.4 g/10 min, 3.5 g/10 min, 3.6 g/10 min, 3.7 g/10 min, 3.8 g/10 min and 3.9 g/10 min.
  • the molecular weight distribution index of the second polypropylene is about 4.5-5.2, including but not limited to 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1 and 5.2.
  • the isotacticity of the second polypropylene is about 89%-97%, including but not limited to 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96% and 97%.
  • the isotacticity of the second polypropylene is about 90%-96%, which can synergize the surface tension, free volume, mechanical properties, yield and film-forming properties of the composite polypropylene material.
  • the difference between the isotacticity of the first polypropylene and the isotacticity of the polypropylene of the present invention is about 1%-8%, preferably 2%-8%, so that the second modified layer and the core layer can be gradually transitioned, which can not only avoid the problem of stress concentration, but also improve the overall strength and toughness of the multilayer structure. It can also avoid the risk of interlayer delamination or cracking caused by interface stress caused by performance mismatch between adjacent layers.
  • the second antioxidant is selected from one or more of triphenyl phosphite, butylated hydroxyanisole, 2,6-di-tert-butyl-4-methylphenol and p-tert-butylcatechol.
  • the second modified layer includes about 0%-79.8% of the second polypropylene, about 20%-99.9% of the second modified polypropylene, and about 0.1%-0.6% of the second antioxidant.
  • the content of the second polypropylene includes but is not limited to 0%, 2%, 5%, 10%, 15%, 20%, 22%, 23%, 24%, 25%, 26%, 28%, 30%, 32%, 33%, 34%, 36%, 38%, 40%, 41%, 42%, 44%, 45%, 46%, 49.8%, 50%, 51%, 52%, 55%, 58%, 60%, 62%, 65%, 70%, 72%, 75% and 79.8%.
  • the second modified layer includes about 20%-50% of the second polypropylene by weight.
  • the content of the second modified polypropylene includes but is not limited to 20%, 22%, 23%, 24%, 25%, 26%, 28%, 30%, 32%, 33%, 34%, 36%, 38%, 40%, 41%, 42%, 44%, 45%, 46%, 48%, 50%, 51%, 52%, 55%, 58%, 60%, 62%, 65%, 70%, 72%, 75%, 80%, 85%, 88%, 90%, 92%, 95%, 96%, 99.8% and 99.9%.
  • the second modified layer includes about 20%-99.8% of the second modified polypropylene in terms of mass percentage.
  • the content of the second antioxidant includes, but is not limited to, 0.1%, 0.2%, 0.3%, 0.4%, 0.5% and 0.6%.
  • the second modified layer includes the second anti- The oxidant is about 0.2%-0.5%.
  • the melt index of the polypropylene of the core layer is about (3.0-3.9) g/10min/(230°C/2.16kg), including but not limited to 3.0 g/10min, 3.1 g/10min, 3.2 g/10min, 3.3 g/10min, 3.4 g/10min, 3.5 g/10min, 3.6 g/10min, 3.7 g/10min, 3.8 g/10min and 3.9 g/10min.
  • the molecular weight distribution index of the polypropylene of the core layer is about 4.5-5.2, including but not limited to 4.5, 4.6, 4.7, 4.8, 4.8, 4.9, 5.0, 5.1 and 5.2.
  • the isotacticity of the polypropylene of the core layer is about ⁇ 97%, including but not limited to 97%, 98%, 99% and 100%.
  • the core layer further includes a third antioxidant.
  • the third antioxidant is selected from one or more of triphenyl phosphite, butylated hydroxyanisole, 2,6-di-tert-butyl-4-methylphenol, and p-tert-butylcatechol.
  • the core layer comprises about 99.5%-99.8% of the polypropylene and about 0.2%-0.5% of the third antioxidant, based on mass percentage.
  • the thickness of the multi-layer composite polypropylene material is about ⁇ 1 ⁇ m, so the thinner the polypropylene film is, the more it can promote the improvement of the energy density of the composite current collector, while taking into account the difficulty of production (the thinner the film, the greater the difficulty of production, and the lower the yield rate). In some embodiments, the thickness of the multi-layer composite polypropylene material is about 2 ⁇ m-20 ⁇ m. Among them, in the composite polypropylene material, the thickness proportions of the first modified layer and the second modified layer are independently about 5%-15%, and the thickness proportion of the core layer is about 70%-90%.
  • the present invention greatly improves the stability of the surface tension while ensuring the mechanical properties of the multi-layer composite polypropylene material by controlling the thickness and thickness proportion of the first modified layer, the second modified layer and the core layer, and by controlling the isotacticity of the polypropylene in the first modified layer, the second modified layer and the core layer, thereby solving the current problems of modified polypropylene film.
  • the problem is that high surface tension and excellent mechanical properties cannot be achieved at the same time.
  • the free volume fraction of the multi-layer composite polypropylene material is 0.018-0.04, which can enhance the bonding force between the metal layer and the multi-layer composite polypropylene material.
  • the present invention also provides a method for preparing the multi-layer composite polypropylene material as described above.
  • the technical scheme is as follows:
  • a method for preparing the multilayer composite polypropylene material as described above comprises the following steps:
  • the first modified layer intermediate, the core layer intermediate and the second modified layer intermediate are composite-molded by a sheet-making process at about 15-60° C. to prepare a multi-layer composite polypropylene material intermediate;
  • the multi-layer composite polypropylene material intermediate is subjected to synchronous stretching treatment to prepare the multi-layer composite polypropylene material, and the total longitudinal stretching ratio is about 5-9 times and the total transverse stretching ratio is about 4-8 times.
  • the synchronous stretching comprises the following steps:
  • the inventors of the present invention have found that the first stretching treatment, the second stretching treatment and the third stretching treatment can promote the orderly arrangement of polymer chains and the formation of lattice structures, better control the orientation and arrangement of polymer chains, and reduce the internal stress of polymer films during the stretching process, thereby improving the crystallization performance, mechanical properties and dimensional stability of multi-layer composite polypropylene materials.
  • the multi-step stretching treatment is combined with the multi-step heat setting treatment, the internal stress in the material can be effectively released, the deformation and thermal deformation tendency of the material can be reduced, and the dimensional stability of the material can be improved; the microstructure of the polymer material can also be regulated, thereby improving its mechanical properties and reducing surface defects.
  • the synchronous stretching includes two stages of preheating, three stages of stretching and two stages of heat setting;
  • the two-stage preheating includes a first preheating and a second preheating, and the temperature is gradually increased, the first preheating temperature is about 130-145°C, and the second preheating temperature is about 145-155°C;
  • the three-stage stretching includes a first stretching, a second stretching and a third stretching, and the temperature is gradually increased, the first stretching temperature is about 152-157° C., the second stretching temperature is about 156-160° C., and the third stretching temperature is about 159-162° C.; after the three-stage stretching, the total longitudinal stretching ratio is about 5-9 times (such as 5, 6, 7, 8, 9, in one embodiment, the total longitudinal stretching ratio is about 6-8 times), and the total transverse stretching ratio is about 4-8 times (such as 4, 5, 6, 7, 8, in one embodiment, the total transverse stretching ratio is about 5-7 times);
  • the two heat setting processes include a first heat setting process and a second heat setting process, and the temperature is gradually increased.
  • the first heat setting temperature is about 162-165° C.
  • the second heat setting temperature is about 162-169° C.
  • Another method for preparing the multilayer composite polypropylene material as described above comprises the following steps:
  • the raw material containing the polypropylene is melted at about 200-260°C, and the raw material containing the polypropylene is melted at about 230-260°C. Extrusion to prepare a core layer intermediate;
  • the first modified layer intermediate, the core layer intermediate and the second modified layer intermediate are composite-molded by a sheet-making process at about 15-60° C. to prepare a multi-layer composite polypropylene material intermediate;
  • the multi-layer composite polypropylene material intermediate is subjected to asynchronous stretching treatment to prepare the multi-layer composite polypropylene material, and the total longitudinal stretching ratio is about 5-9 times and the total transverse stretching ratio is about 4-8 times.
  • the asynchronous stretching comprises the following steps:
  • thermoforming treatment on the multi-layer composite polypropylene material III at a temperature of about 165-170° C. to prepare a multi-layer composite polypropylene material IV;
  • the multi-layer composite polypropylene material IV is heat-treated at about 120-135° C. to prepare the multi-layer composite polypropylene material.
  • the longitudinal stretching comprises the following steps:
  • the transverse stretching comprises the following steps:
  • Preheating at about 120-140°C, stretching at about 150-160°C, thermoforming at about 165-170°C, and the total transverse stretching ratio is about 4-8 times (such as 4, 5, 6, 7, 8, in which one of the actual In the embodiment, the total transverse stretching ratio is about 5-7 times);
  • the heat treatment comprises the following steps:
  • the heat treatment is carried out at about 120-135°C to eliminate the internal stress of the membrane and improve the thermal stability of the membrane.
  • the method for preparing the multi-layer composite polypropylene material comprises the following steps:
  • the raw materials used for the first modified layer, core layer and second modified layer are respectively added into the corresponding twin-screw extruder, melted at about 200-260°C, and then filtered through a filter (10 micron filter screen), and the melt is extruded through a die head.
  • the die head temperature is about 230-260°C, and the extrusion amount of the three layers is controlled at about (5%-15%): (70%-90%): (5%-15%).
  • the molten polyester material extruded from the die head is cast onto the casting roll and is formed by the casting roll and water cooling treatment.
  • the cooling temperature is about 15-60°C.
  • Biaxial stretching can be achieved in two ways, namely synchronous stretching and asynchronous stretching.
  • preheating area preheating area
  • stretching area stretch area
  • heat setting area preheating area
  • Preheating zone divided into two sections, the temperature increases successively, i.e. about 130-145°C and about 145-155°C;
  • Stretching zone divided into three sections, the temperature increases successively, namely about 152-157°C, about 156-160°C, about 159-162°C; after three-stage stretching, the stretching ratio: the total longitudinal stretching ratio is about 5-9 times, and the total transverse stretching ratio is about 4-8 times.
  • Heat setting area divided into two sections, the temperature increases successively, i.e. about 162-165°C and about 162-169°C.
  • preheating temperature is about 110-135°C
  • stretching temperature is about 140-150°C
  • total longitudinal stretching ratio is about 5-9 times, and then cooled to room temperature.
  • Transverse stretching preheating temperature is about 120-140°C; stretching temperature is about 150-160°C; heat setting temperature is about 165-170°C; total transverse stretching ratio is about 4-8 times.
  • the heat treatment temperature is about 120-135°C, the purpose is to eliminate the internal stress of the membrane and improve the thermal stability of the membrane.
  • the film After heat treatment, the film is air-cooled in the platform area and then enters the winding system through the traction system for film winding.
  • the winding tension is about 20-30N/m.
  • the present invention also provides a composite current collector, the structure of which includes a first protective layer, a first metal layer, a support layer, a second metal layer and a second protective layer arranged in layers;
  • the support layer comprises a composite polypropylene material according to above.
  • the composite polypropylene material provided by the present invention has high and stable surface tension, excellent surface adhesion performance, strong metal bonding, and can be firmly bonded to metal.
  • the composite polypropylene material prepared by the present invention is used as a support layer of a composite current collector (a carrier of a composite current collector), which can firmly bond to a metal layer and improve battery performance.
  • the thickness of the support layer is about 1 ⁇ m-20 ⁇ m, which better meets the application requirements of the composite current collector while taking into account the difficulty and cost of the preparation process.
  • the two metal layers are located on both sides of the support layer and function as a conductor. It is understandable that the materials of the two metal layers may be consistent or inconsistent, and the thicknesses may be consistent or inconsistent.
  • the first metal layer and the second metal layer independently include: a metal and an alloy thereof with a resistivity of about ⁇ 8 ⁇ 10-8 ⁇ m.
  • the metal with a resistivity of about ⁇ 8 ⁇ 10-8 ⁇ m is one or more of copper, aluminum, silver, gold, zinc, molybdenum, cobalt and nickel, and the alloy that meets the requirements is selected from one or more of copper alloy, aluminum alloy and nickel alloy.
  • the thickness of the first metal layer and the second metal layer are independently about 500 nm-2000 nm.
  • the thickness of the first metal layer and the second metal layer are independently about 700 nm-1200 nm, which can have better conductivity.
  • the first metal layer and the second metal layer are independently prepared by one or more methods such as physical vapor deposition (such as resistance heating vacuum evaporation, electron beam heating vacuum evaporation, laser heating vacuum evaporation, magnetron sputtering, etc.), electroplating, and chemical plating.
  • physical vapor deposition such as resistance heating vacuum evaporation, electron beam heating vacuum evaporation, laser heating vacuum evaporation, magnetron sputtering, etc.
  • electroplating such as electroplating, and chemical plating.
  • the first protective layer and the second protective layer are arranged on the side of the metal layer away from the support layer to prevent the metal conductive layer from being chemically corroded or physically damaged. It can be understood that the materials of the two protective layers can be consistent or inconsistent, and the thickness can be consistent or inconsistent.
  • the first protective layer and the second protective layer independently include: one or more of inactive metals and alloys thereof, metal oxides and carbon materials.
  • the inactive metal is selected from nickel and/or chromium.
  • the inactive metal alloy is selected from one or more of nickel-based alloys, chromium-based alloys, and nickel-chromium-copper alloys.
  • the metal oxide is selected from one or more of copper oxide, aluminum oxide, nickel oxide, chromium oxide, cobalt oxide, and copper-chromium oxide.
  • the carbon material is selected from one or more of graphite, carbon black, acetylene black, Ketjen black, carbon nano quantum dots, carbon nanotubes, carbon nanofibers, and graphene.
  • the thickness of the first protective layer and the second protective layer are independently about 10 nm-150 nm.
  • the thickness of the first protective layer and the second protective layer are respectively about 20nm-100nm, and the thickness of the protective layer shall not exceed one tenth of the thickness of the metal layer.
  • the preparation methods of the first protective layer and the second protective layer are independently one or more of physical vapor deposition, chemical vapor deposition, in-situ forming, coating, etc.
  • the vapor deposition method is vacuum evaporation or magnetron sputtering;
  • the chemical vapor deposition is atmospheric pressure chemical vapor deposition or plasma enhanced chemical vapor deposition;
  • the in-situ forming is a method of in-situ forming a metal oxide passivation layer on the surface of the metal layer;
  • the coating method is die coating, blade coating or extrusion coating.
  • FIG. 4 is a schematic diagram of the structure of a composite current collector in an embodiment of the present invention, wherein 401 is a first protective layer, 402 is a first metal layer, 403 is a support layer, 404 is a second metal layer, and 405 is a second protective layer.
  • the present invention also provides a pole piece, comprising the composite current collector as described above.
  • the present invention also provides a battery, comprising the pole piece as described above.
  • Embodiment 1 is a diagrammatic representation of Embodiment 1:
  • This embodiment provides a multi-layer composite polypropylene film and a preparation method thereof, a composite current collector and a preparation method thereof.
  • the first modified layer is composed as follows: First Polypropylene 79.8%; First modified polypropylene 20%; First antioxidant 0.2%;
  • the melt index of the first polypropylene is 3.0g/10min/(230°C/2.16kg), the molecular weight distribution index is 5.2, and the isotacticity is 96%.
  • the first modified polypropylene is polypropylene grafted with maleic anhydride, and its melt index is 3.2g/10min/(230°C/2.16kg), the molecular weight distribution index is 5.5, and the grafting rate is 0.2%.
  • the first antioxidant is triphenyl phosphite.
  • the core layer composition is as follows: Polypropylene 99.8%; tertiary antioxidant 0.2%;
  • the melt index of polypropylene is 3.0 g/10 min/(230° C./2.16 kg), the molecular weight distribution index is 5.2, the isotacticity is 97%, and the third antioxidant is triphenyl phosphite.
  • the second modified layer is composed as follows: second polypropylene 79.8%; Second modified polypropylene 20%; Second antioxidant 0.2%;
  • the melt index of the second polypropylene is 3.0g/10min/(230°C/2.16kg), the molecular weight distribution index is 5.2, and the isotacticity is 96%.
  • the second modified polypropylene is polypropylene grafted with maleic anhydride, and its melt index is 3.2g/10min/(230°C/2.16kg), the molecular weight distribution index is 5.5, and the grafting rate is 0.2%.
  • the second antioxidant is triphenyl phosphite.
  • the raw materials of the first modified layer, the core layer and the second modified layer are respectively added into the corresponding twin-screw extruder, melted at 250°C, filtered through a filter (10 micron filter screen), and then extruded through a die head with a die head temperature of 260°C.
  • the extrusion ratio of the three layers is controlled at 10%:80%:10%.
  • the molten polyester material extruded from the die head is cast onto the casting roll, and is formed by the casting roll and water cooling treatment, and the cooling temperature is 30°C.
  • the synchronous stretching process is as follows: it is divided into three areas: preheating area, stretching area, and heat setting area. Specifically:
  • Preheating zone divided into two sections, the temperature increases successively, i.e. 135°C and 150°C;
  • Stretching zone divided into three sections, the temperature increases successively, namely 153°C, 157°C, 160°C; stretching ratio: the total longitudinal stretching ratio is 6 times, and the total transverse stretching ratio is 5 times;
  • Heat setting area divided into two sections, the temperature increases successively, namely 163°C and 166°C.
  • the heat-treated film After the heat-treated film is air-cooled in the platform area, it enters the winding system through the traction system for film winding, and the winding tension is 30N/m.
  • a multi-layer composite polypropylene film with a total thickness of 4.5 microns is prepared, the thickness of the first modified layer and the second modified layer are both 0.45 microns, and the thickness of the core layer is 3.6 microns.
  • metal conductive layer Preparation of metal conductive layer: The multi-layer composite polypropylene film prepared as above and cleaned on the surface is placed in a vacuum evaporation chamber, and the high-purity aluminum wire (purity greater than 99.99%) in the metal evaporation chamber is melted and evaporated at a high temperature of 1300-2000°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and are deposited on the two surfaces of the polymer base film to form an aluminum metal conductive layer with a thickness of 1 micron.
  • Embodiment 2 is a diagrammatic representation of Embodiment 1:
  • the method is basically the same as Example 1, except that the content of each raw material in the modified layer is changed, specifically:
  • polypropylene, maleic anhydride grafted modified polypropylene, and triphenyl phosphite in the first modified layer are 49.8%, 50.0%, and 0.2%, respectively;
  • polypropylene, polypropylene grafted with maleic anhydride and triphenyl phosphite in the second modified layer are 49.8%, 50.0% and 0.2% respectively.
  • Embodiment 3 is a diagrammatic representation of Embodiment 3
  • the method is basically the same as Example 1, except that the content of each raw material in the modified layer is changed, specifically:
  • polypropylene, maleic anhydride grafted modified polypropylene, and triphenyl phosphite in the first modified layer are 0%, 99.8%, and 0.2%, respectively;
  • polypropylene, polypropylene grafted with maleic anhydride, and triphenyl phosphite in the second modified layer are 0%, 99.8%, and 0.2%, respectively.
  • Embodiment 4 is a diagrammatic representation of Embodiment 4:
  • the method is basically the same as Example 1, except that the content of each raw material in the modified layer is changed, specifically:
  • polypropylene, polypropylene grafted with maleic anhydride, and triphenyl phosphite in the first modified layer are 79.5%, 20.0%, and 0.5%, respectively;
  • polypropylene, polypropylene grafted with maleic anhydride and triphenyl phosphite in the second modified layer are 79.5%, 20.0% and 0.5% respectively.
  • Embodiment 5 is a diagrammatic representation of Embodiment 5:
  • the method is basically the same as Example 1, except that the content of each raw material in the modified layer is changed, specifically:
  • the first modified layer contains polypropylene, maleic anhydride grafted modified polypropylene, and triphenyl phosphite. The contents are 80.8%, 19.0%, and 0.2% respectively;
  • polypropylene, polypropylene grafted with maleic anhydride, and triphenyl phosphite in the second modified layer are 80.8%, 19.0%, and 0.2%, respectively.
  • Embodiment 6 is a diagrammatic representation of Embodiment 6
  • the method is basically the same as Example 1, except that the content of each raw material in the modified layer is changed, specifically:
  • polypropylene, maleic anhydride grafted modified polypropylene, and triphenyl phosphite in the first modified layer are 0%, 99.9%, and 0.1%, respectively;
  • polypropylene, polypropylene grafted with maleic anhydride and triphenyl phosphite in the second modified layer are 0%, 99.9% and 0.1% respectively.
  • Embodiment 7 is a diagrammatic representation of Embodiment 7:
  • the method is basically the same as Example 2, except that the grafting rate of the modified polypropylene in the modified layer is changed, specifically:
  • the grafting rate of polypropylene modified by maleic anhydride grafting in the first modified layer is 0.9%;
  • the grafting rate of the polypropylene modified by grafting with maleic anhydride in the second modified layer was 0.9%.
  • Embodiment 8 is a diagrammatic representation of Embodiment 8
  • the method is basically the same as Example 2, except that the grafting rate of the modified polypropylene in the modified layer is changed, specifically:
  • the grafting rate of polypropylene modified by maleic anhydride grafting in the first modified layer is 1.5%;
  • the grafting rate of the polypropylene modified by grafting with maleic anhydride in the second modified layer was 1.5%.
  • Embodiment 9 is a diagrammatic representation of Embodiment 9:
  • the method is basically the same as Example 2, except that the grafting rate of the modified polypropylene in the modified layer is changed, specifically:
  • the grafting rate of polypropylene modified by maleic anhydride grafting in the first modified layer is 0.1%
  • the grafting rate of the polypropylene modified by grafting with maleic anhydride in the second modified layer was 0.1%.
  • Embodiment 10 is a diagrammatic representation of Embodiment 10:
  • the method is basically the same as Example 2, except that the grafting rate of the modified polypropylene in the modified layer is changed, specifically:
  • the grafting rate of maleic anhydride grafted polypropylene in the first modified layer is 1.6%;
  • the grafting rate of the polypropylene modified by grafting with maleic anhydride in the second modified layer was 1.6%.
  • Embodiment 11 is a diagrammatic representation of Embodiment 11:
  • the method is substantially the same as Example 7, except that the melt index of the modified polypropylene in the modified layer is changed, specifically:
  • the melt index of the maleic anhydride grafted modified layer in the first modified layer is 3.6 g/10 min/(230°C/2.16 kg);
  • the melt index of the maleic anhydride grafted modified layer in the second modified layer was 3.6 g/10 min/(230° C./2.16 kg).
  • Embodiment 12 is a diagrammatic representation of Embodiment 12
  • the method is substantially the same as Example 7, except that the melt index of the modified polypropylene in the modified layer is changed, specifically:
  • the melt index of the maleic anhydride grafted modified layer in the first modified layer is 4.0 g/10 min/(230°C/2.16 kg);
  • the melt index of the maleic anhydride grafted modified layer in the second modified layer was 4.0 g/10 min/(230° C./2.16 kg).
  • Embodiment 13 is a diagrammatic representation of Embodiment 13:
  • the method is substantially the same as Example 7, except that the melt index of the modified polypropylene in the modified layer is changed, specifically:
  • the melt index of the maleic anhydride grafted modified layer in the first modified layer is 3.1 g/10 min/(230°C/2.16 kg);
  • the melt index of the maleic anhydride grafted modified layer in the second modified layer was 3.1 g/10 min/(230° C./2.16 kg).
  • Embodiment 14 is a diagrammatic representation of Embodiment 14:
  • the method is substantially the same as Example 7, except that the melt index of the modified polypropylene in the modified layer is changed, specifically:
  • the melt index of the maleic anhydride grafted modified layer in the first modified layer is 4.1 g/10 min/(230°C/2.16 kg);
  • the melt index of the maleic anhydride grafted modified layer in the second modified layer was 4.1 g/10 min/(230° C./2.16 kg).
  • Embodiment 15 is a diagrammatic representation of Embodiment 15:
  • the molecular weight distribution index of the maleic anhydride graft modification in the first modified layer is 5.0;
  • the molecular weight distribution index of the maleic anhydride graft modification in the second modified layer was 5.0.
  • Embodiment 16 is a diagrammatic representation of Embodiment 16:
  • the method is basically the same as Example 11, except that the molecular weight distribution index of the modified polypropylene in the modified layer is changed, specifically:
  • the molecular weight distribution index of maleic anhydride graft modification in the first modified layer is 4.6;
  • the molecular weight distribution index of the maleic anhydride graft modification in the second modified layer was 4.6.
  • Embodiment 17 is a diagrammatic representation of Embodiment 17:
  • the method is basically the same as Example 11, except that the molecular weight distribution index of the modified polypropylene in the modified layer is changed, specifically:
  • the molecular weight distribution index of maleic anhydride graft modification in the first modified layer is 5.6;
  • the molecular weight distribution index of the maleic anhydride graft modification in the second modified layer was 5.6.
  • Embodiment 18 is a diagrammatic representation of Embodiment 18:
  • the method is basically the same as Example 15, except that the molecular weight distribution index of the modified polypropylene in the modified layer is changed, specifically:
  • the molecular weight distribution index of the maleic anhydride grafted modification in the first modified layer is 4.5;
  • the molecular weight distribution index of the maleic anhydride graft modification in the second modified layer was 4.5.
  • Embodiment 19 is a diagrammatic representation of Embodiment 19:
  • Example 15 It is basically the same as Example 15, except that the longitudinal stretching ratio in the synchronous stretching is changed, and the total longitudinal stretching ratio after three-stage stretching treatment is 7:1.
  • Embodiment 20 is a diagrammatic representation of Embodiment 20.
  • Example 15 It is basically the same as Example 15, except that the longitudinal stretching ratio in the synchronous stretching is changed, and the total longitudinal stretching ratio after three-stage stretching treatment is 8:1.
  • Embodiment 21 is a diagrammatic representation of Embodiment 21.
  • Example 15 It is basically the same as Example 15, except that the longitudinal stretching ratio in the synchronous stretching is changed, and the total longitudinal stretching ratio after three-stage stretching treatment is 5:1.
  • Example 15 It is basically the same as Example 15, except that the longitudinal stretching ratio in the synchronous stretching is changed, and the total longitudinal stretching ratio after three-stage stretching treatment is 9:1.
  • Embodiment 23 is a diagrammatic representation of Embodiment 23.
  • the method is basically the same as Example 1, except that the content of each raw material of the core layer is changed, specifically:
  • polypropylene and triphenyl phosphite are 99.5% and 0.5% respectively.
  • Embodiment 24 is a diagrammatic representation of Embodiment 24.
  • Example 19 It is basically the same as Example 19, except that the polypropylene modified by grafting maleic anhydride in the first modified layer and the second modified layer is replaced by polypropylene modified by grafting glycidyl acrylate.
  • Embodiment 25 is a diagrammatic representation of Embodiment 25.
  • Example 19 It is basically the same as Example 19, except that the type of modified polypropylene is changed, specifically, the polypropylene grafted modified with maleic anhydride in the first modified layer and the second modified layer is replaced with polypropylene grafted modified with diethylenetriamine-glycidyl methacrylate.
  • Embodiment 26 is a diagrammatic representation of Embodiment 26.
  • Example 2 It is basically the same as Example 1, except that: the isotacticity of the polypropylene in the first modified layer and the second modified layer is changed, specifically: the isotacticity of the polypropylene in the first modified layer and the second modified layer is 93%.
  • Embodiment 27 is a diagrammatic representation of Embodiment 27.
  • Example 2 It is basically the same as Example 1, except that: the isotacticity of the polypropylene in the first modified layer and the second modified layer is changed, specifically: the isotacticity of the polypropylene in the first modified layer and the second modified layer is 90%.
  • Embodiment 28 is a diagrammatic representation of Embodiment 28:
  • Example 2 It is basically the same as Example 1, except that: the isotacticity of the polypropylene in the first modified layer and the second modified layer is changed, specifically: the isotacticity of the polypropylene in the first modified layer and the second modified layer is 89%.
  • Embodiment 29 is a diagrammatic representation of Embodiment 29.
  • Example 2 It is basically the same as Example 1, except that: the isotacticity of the polypropylene in the first modified layer and the second modified layer is changed, specifically: the isotacticity of the polypropylene in the first modified layer and the second modified layer is 97%.
  • Embodiment 30 is a diagrammatic representation of Embodiment 30.
  • Example 2 It is basically the same as Example 1, except that the isotacticity of the polypropylene used in the core layer is 99%.
  • Embodiment 31 is a diagrammatic representation of Embodiment 31.
  • Example 2 It is basically the same as Example 1, except that the isotacticity of the polypropylene used in the core layer is 96%.
  • Embodiment 32 is a diagrammatic representation of Embodiment 32.
  • Example 2 It is basically the same as Example 1, except that the concentration of the antioxidant triphenyl phosphite used in the first modified layer, the core layer and the second modified layer is 0.1%.
  • the contents of polypropylene, maleic anhydride grafted polypropylene, and triphenyl phosphite in the first modified layer are 79.9%, 20%, and 0.1%, respectively;
  • the contents of polypropylene and triphenyl phosphite in the core layer are 99.9% and 0.1% respectively;
  • polypropylene, polypropylene grafted with maleic anhydride and triphenyl phosphite in the second modified layer are 79.9%, 20% and 0.1% respectively.
  • Embodiment 33 is a diagrammatic representation of Embodiment 33.
  • Example 2 It is basically the same as Example 1, except that the concentration of the antioxidant triphenyl phosphite used in the first modified layer, the core layer and the second modified layer is 0.6%.
  • the contents of polypropylene, maleic anhydride grafted polypropylene, and triphenyl phosphite in the first modified layer are 79.4%, 20%, and 0.6%, respectively;
  • the contents of polypropylene and triphenyl phosphite in the core layer are 99.4% and 0.6% respectively;
  • polypropylene, polypropylene grafted with maleic anhydride and triphenyl phosphite in the second modified layer are 79.4%, 20% and 0.6% respectively.
  • Embodiment 34 is a diagrammatic representation of Embodiment 34.
  • the method is basically the same as Example 1, except that the content of the polypropylene grafted with maleic anhydride in the second modified layer is changed, specifically:
  • the first modified layer is composed as follows: First Polypropylene 79.8%; First modified polypropylene 20%; First antioxidant 0.2%;
  • the melt index of the first polypropylene is 3.0g/10min/(230°C/2.16kg), the molecular weight distribution index is 5.2, and the isotacticity is 96%.
  • the first modified polypropylene is polypropylene grafted with maleic anhydride, and its melt index is 3.2g/10min/(230°C/2.16kg), the molecular weight distribution index is 5.5, and the grafting rate is 0.2%.
  • the first antioxidant is triphenyl phosphite.
  • the core layer composition is as follows: Polypropylene 99.8%; tertiary antioxidant 0.2%;
  • the melt index of polypropylene is 3.0 g/10 min/(230° C./2.16 kg), the molecular weight distribution index is 5.2, the isotacticity is 97%, and the third antioxidant is triphenyl phosphite.
  • the second modified layer is composed as follows: second polypropylene 69.8%; Second modified polypropylene 30%; Second antioxidant 0.2%;
  • the second polypropylene has a melt index of 3.0 g/10 min/(230° C./2.16 kg), a molecular weight distribution index of 5.2, and an isotacticity of 96%.
  • the second modified polypropylene is a polypropylene grafted with maleic anhydride. Its melt index is 3.2 g/10 min/(230° C./2.16 kg), its molecular weight distribution index is 5.5, its grafting rate is 0.2%, and its second antioxidant is triphenyl phosphite.
  • Embodiment 35 is a diagrammatic representation of Embodiment 35.
  • the method is basically the same as Example 1, except that the type of modified polypropylene in the second modified layer is changed, specifically:
  • the first modified layer is composed as follows: First Polypropylene 79.8%; First modified polypropylene 20%; First antioxidant 0.2%;
  • the melt index of the first polypropylene is 3.0g/10min/(230°C/2.16kg), the molecular weight distribution index is 5.2, and the isotacticity is 96%.
  • the first modified polypropylene is polypropylene grafted with maleic anhydride, and its melt index is 3.2g/10min/(230°C/2.16kg), the molecular weight distribution index is 5.5, and the grafting rate is 0.2%.
  • the first antioxidant is triphenyl phosphite.
  • the core layer composition is as follows: Polypropylene 99.8%; tertiary antioxidant 0.2%;
  • the melt index of polypropylene is 3.0 g/10 min/(230° C./2.16 kg), the molecular weight distribution index is 5.2, the isotacticity is 97%, and the third antioxidant is triphenyl phosphite.
  • the second modified layer is composed as follows: second polypropylene 79.8%; Second modified polypropylene 20%; Second antioxidant 0.2%;
  • the melt index of the second polypropylene is 3.0g/10min/(230°C/2.16kg), the molecular weight distribution index is 5.2, and the isotacticity is 96%.
  • the second modified polypropylene is diethylenetriamine-methacrylate grafted modified polypropylene, and its melt index is 3.2g/10min/(230°C/2.16kg), the molecular weight distribution index is 5.5, and the grafting rate is 0.2%.
  • the second antioxidant is triphenyl phosphite.
  • Embodiment 36 is a diagrammatic representation of Embodiment 36.
  • Example 19 It is basically the same as Example 19, except that the modified polypropylene in the first and second modified layers is polypropylene graft-modified with maleic anhydride oligomer (degree of polymerization is 10).
  • Embodiment 37 is a diagrammatic representation of Embodiment 37.
  • Example 19 It is basically the same as Example 19, except that the modified polypropylene in the first and second modified layers is polypropylene grafted with succinylfluorescein-succinic anhydride.
  • Embodiment 38 is a diagrammatic representation of Embodiment 38.
  • the modified polypropylene in the first and second modified layers is a mixture of polypropylene grafted with maleic anhydride oligomer (degree of polymerization is 10) and polypropylene grafted with succinylfluorescein-succinic anhydride, and the mass ratio of the two is 1:1.
  • the method is basically the same as Example 1, except that no polypropylene modified by grafting maleic anhydride is added to the first modified layer and the second modified layer.
  • Example 2 The same as Example 1, except that the first modified layer does not contain maleic anhydride grafted modified Polypropylene.
  • Example 2 It is basically the same as Example 1, except that: all three layers are modified layers: that is, the contents of polypropylene, maleic anhydride grafted modified polypropylene, and triphenyl phosphite in the first modified layer, the second modified layer, and the core layer are 79.8%, 20%, and 0.2%, respectively.
  • the method is basically the same as Example 1, except that: the synchronous stretching is set to 1 stage, the stretching is in place in one step, the temperature is 160°C; the stretching ratio: the total longitudinal stretching ratio is 6 times, and the total transverse stretching ratio is 5 times;
  • the method is basically the same as Example 2, except that the grafting rate of the modified polypropylene in the modified layer is changed, specifically:
  • the grafting rate of polypropylene modified by maleic anhydride grafting in the first modified layer is 2.2%;
  • the grafting rate of the polypropylene modified by grafting with maleic anhydride in the second modified layer was 2.2%.
  • the purpose of preparing the multilayer composite polypropylene film is to improve the surface adhesion performance of the film and Mechanical properties, thereby improving the performance of the composite current collector prepared with this polypropylene film as the substrate.
  • the factors affecting the surface adhesion performance of the polypropylene film namely the surface tension and surface free volume, the adhesion between the multi-layer composite polypropylene film and the surface metal layer in the composite current collector, and other indicators are tested and characterized.
  • the tensile strength of the prepared multi-layer composite polypropylene film and the defective rate caused by surface defects are also tested.
  • the specific test methods are as follows:
  • the bonding strength between the multi-layer composite polypropylene film and the metal layer in the composite current collector a layer of Permacel P-94 double-sided tape is bonded on a 1mm thick aluminum foil, the composite current collector is bonded on the double-sided tape, and a layer of ethylene acrylic acid copolymer film (DuPont Nurcel0903, thickness of 50 ⁇ m) is covered on the composite current collector, and then hot-pressed at 1.3 ⁇ 105N/m2 and 120°C for 10s, cooled to room temperature, and cut into 150mm ⁇ 15mm strips. Finally, the ethylene acrylic acid copolymer film of the sample strip is fixed to the upper fixture of the tensile machine, and the rest is fixed to the lower fixture. After fixing, the two are peeled at an angle of 180o and a speed of 100mm/min to test the peeling force, that is, the bonding strength between the multi-layer composite polypropylene film and the metal layer.
  • Adhesion 1 and Adhesion 2 in the table represent the adhesion between the first modified layer, the second modified layer and the metal layer of the multi-layer composite polypropylene film, respectively.
  • the tensile strength of the prepared multi-layer composite polypropylene film basically shows a trend of first increasing and then remaining basically unchanged when the content of the antioxidant in the modified layer and the core layer is increased. This is because the increase in the content of the antioxidant can reduce the degradation rate of polypropylene during the melting process, thereby reducing the decrease in the average molecular weight of polypropylene. However, the increase in the content of the antioxidant in the modified layer and the core layer has little effect on the surface tension and free volume of the modified layer.
  • Example 1 It can be seen from Example 1 and Comparative Example 5 that, compared with one-step stretching, multiple stretching treatments can make the prepared multi-layer composite polypropylene film have better tensile strength and lower defective rate.
  • the composite current collector samples prepared in Examples 1, 2, 3 and Comparative Example 1 are used as the electrode current collectors of the battery, and lithium iron phosphate is used as the positive electrode material, graphite is used as the negative electrode material, and carbonate is used as the electrolyte to prepare soft-pack batteries.
  • the prepared batteries are subjected to cycle experiments at a charge and discharge rate of 0.5C, and the changes in energy density (unit mass of active electrode material) with the number of cycles are shown in Figure 5.

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Abstract

A multilayer composite polypropylene material, and a preparation method therefor and the use thereof. The multilayer composite polypropylene material comprises a first modified layer (101), a core layer (102) and a second modified layer (103) which are arranged in a stacked manner, wherein the first modified layer (101) comprises a first modified polypropylene; the core layer (102) comprises polypropylene; the second modified layer (103) comprises a second modified polypropylene; and the first modified polypropylene and the second modified polypropylene are each independently selected from: one or more of maleic anhydride graft modified polypropylene, acrylic acid–maleic anhydride graft modified polypropylene, diethylenetriamine–glycidyl methacrylate graft modified polypropylene, acrylamide graft modified polypropylene, acrylamide–acrylic acid graft modified polypropylene, succinic anhydride grafted polypropylene, succinyl fluorescein–succinic anhydride grafted polypropylene, and modified polypropylenes in which hydrogen in polar modified molecules is substituted by a methyl, an ethyl or a halogen atom; and one or more of maleic anhydride oligomer graft modified polypropylene, (acrylic acid–maleic anhydride) oligomer graft modified polypropylene, glycidyl methacrylate oligomer graft modified polypropylene, di(ethylene triamine–glycidyl methacrylate) oligomer graft modified polypropylene, acrylamide oligomer graft modified polypropylene, (acrylamide–acrylic acid) oligomer graft modified polypropylene, succinic anhydride oligomer grafted polypropylene, (succinyl fluorescein–succinic anhydride) oligomer grafted polypropylene, and modified polypropylenes in which hydrogen in polar modified molecules is substituted by a methyl, an ethyl or a halogen atom.

Description

多层复合聚丙烯材料及其制备方法和应用Multilayer composite polypropylene material and preparation method and application thereof 技术领域Technical Field
本发明涉及复合材料技术领域，特别涉及多层复合聚丙烯材料及其制备方法和应用。The invention relates to the technical field of composite materials, in particular to a multi-layer composite polypropylene material and a preparation method and application thereof.
背景技术Background technique
目前，基于高分子聚合物膜的复合集流体得到新能源行业的广泛关注和应用。该复合集流体的制备过程通常为：采用物理气相沉积(PVD)的方法在高分子薄膜(如聚丙烯、聚乙烯、聚酯类等)上沉积一层金属(铝、铜等)材料。制备出的具备一定导电能力的表面金属化的薄膜即为复合集流体。相比传统的集流体，基于高分子聚合物膜的复合集流体具备成本低、质量轻和内部绝缘性好等优势。这些优势使得复合集流体在电池中应用时能够降低电池的成本、并提升电池的能量密度及安全性。At present, composite current collectors based on polymer films have received widespread attention and application in the new energy industry. The preparation process of the composite current collector is usually: a layer of metal (aluminum, copper, etc.) material is deposited on a polymer film (such as polypropylene, polyethylene, polyester, etc.) by physical vapor deposition (PVD). The prepared surface metallized film with a certain conductivity is the composite current collector. Compared with traditional current collectors, composite current collectors based on polymer films have the advantages of low cost, light weight and good internal insulation. These advantages enable the composite current collector to reduce the cost of the battery and improve the energy density and safety of the battery when used in the battery.
在众多基于高分子聚合物膜的复合集流体中，基于聚丙烯膜的复合集流体较为常见。然而，以传统聚丙烯膜为基膜制备复合集流体过程中，由于聚丙烯膜自身材料极性较弱，导致其表面张力较低，低表面张力的聚丙烯膜与高表面张力的金属层之间的亲合力较差，从而引发二者界面之间的附着力较低，结合不牢固，即存在表面粘附性能差的问题。为了解决这一问题，通常采用聚丙烯膜表面电晕的方法，提高膜的表面张力，从而提升聚丙烯膜与金属材料的结合牢固性，但这一方法存在如下不足：电晕处理后的高分子薄膜表面张力不稳定，存放一段时间后，表面张力降低，最后与处理前的高分子薄膜表面张力接近，即存在存储不稳定的问题。Among the many composite current collectors based on polymer films, composite current collectors based on polypropylene films are more common. However, in the process of preparing composite current collectors with traditional polypropylene films as base films, due to the weak polarity of the polypropylene film itself, its surface tension is low, and the affinity between the polypropylene film with low surface tension and the metal layer with high surface tension is poor, which leads to low adhesion between the interface of the two and weak bonding, that is, there is a problem of poor surface adhesion performance. In order to solve this problem, the method of corona treatment on the surface of polypropylene film is usually adopted to increase the surface tension of the film, thereby improving the bonding firmness between the polypropylene film and the metal material, but this method has the following shortcomings: the surface tension of the polymer film after corona treatment is unstable. After being stored for a period of time, the surface tension decreases and finally approaches the surface tension of the polymer film before treatment, that is, there is a problem of unstable storage.
发明内容 Summary of the invention
根据本申请的各种实施例，提供一种多层复合聚丙烯材料，其表面张力高且存储稳定性好，与金属亲和力强，能与金属牢固结合在一起，其可用于制备复合集流体，进一步用于极片或电池。According to various embodiments of the present application, a multilayer composite polypropylene material is provided, which has high surface tension and good storage stability, strong affinity with metals, and can be firmly combined with metals. It can be used to prepare a composite current collector and further used in pole pieces or batteries.
技术方案如下：The technical solution is as follows:
一种多层复合聚丙烯材料，其结构包括呈层叠设置的第一改性层，芯层和第二改性层；A multi-layer composite polypropylene material, the structure of which comprises a first modified layer, a core layer and a second modified layer which are stacked;
所述第一改性层包括第一改性聚丙烯；The first modified layer includes a first modified polypropylene;
所述芯层包括聚丙烯；The core layer comprises polypropylene;
所述第二改性层包括第二改性聚丙烯；The second modified layer includes a second modified polypropylene;
所述第一改性聚丙烯和第二改性聚丙烯分别独立选自小分子接枝改性的聚丙烯和低聚物接枝改性的聚丙烯中的一种或多种。The first modified polypropylene and the second modified polypropylene are independently selected from one or more of small molecule graft-modified polypropylene and oligomer graft-modified polypropylene.
在一些实施例中，芯层中所述聚丙烯为未改性聚丙烯。In some embodiments, the polypropylene in the core layer is unmodified polypropylene.
在一些实施例中，芯层中所述聚丙烯不包含改性聚丙烯。In some embodiments, the polypropylene in the core layer does not comprise modified polypropylene.
在一些实施例中，小分子接枝改性的聚丙烯包括：顺丁烯二酸酐接枝改性的聚丙烯、丙烯酸-顺丁烯二酸酐接枝改性的聚丙烯、二乙烯三胺-甲基丙烯酸缩水甘油酯接枝改性的聚丙烯、丙烯酰胺接枝改性的聚丙烯、丙烯酰胺-丙烯酸接枝改性聚丙烯、琥珀酸酐接枝聚丙烯、琥珀酰荧光素-琥珀酸酐接枝的聚丙烯和极性改性分子中的氢被甲基、乙基或卤素原子取代的改性聚丙烯中的一种或多种。In some embodiments, the small molecule grafted modified polypropylene includes: maleic anhydride grafted modified polypropylene, acrylic acid-maleic anhydride grafted modified polypropylene, diethylenetriamine-methacrylate glycidyl grafted modified polypropylene, acrylamide grafted modified polypropylene, acrylamide-acrylic acid grafted modified polypropylene, succinic anhydride grafted polypropylene, succinylfluorescein-succinic anhydride grafted polypropylene and one or more of modified polypropylenes in which hydrogen in the polar modified molecules is replaced by methyl, ethyl or halogen atoms.
低聚物接枝改性的聚丙烯包括：顺丁烯二酸酐低聚物接枝改性的聚丙烯、(丙烯酸-顺丁烯二酸酐)低聚物接枝改性的聚丙烯、二(乙烯三胺-甲基丙烯酸缩水甘油酯)低聚物接枝改性的聚丙烯、丙烯酰胺低聚物接枝改性的聚丙烯、(丙烯酰胺-丙烯酸)低聚物接枝改性聚丙烯、琥珀酸酐低聚物接枝聚丙烯、(琥珀酰 荧光素-琥珀酸酐)低聚物接枝的聚丙烯和极性改性分子中的氢被甲基、乙基或卤素原子取代的改性聚丙烯中的一种或多种。其中低聚物的聚合度为2-20，优选5-10，低聚物聚合物度过高易在改性层形成缺陷。优选小分子接枝改性的聚丙烯与低聚物接枝改性的聚丙烯的组合物。The oligomer grafted modified polypropylene includes: polypropylene grafted with maleic anhydride oligomer, polypropylene grafted with (acrylic acid-maleic anhydride) oligomer, polypropylene grafted with di(ethylenetriamine-glycidyl methacrylate) oligomer, polypropylene grafted with acrylamide oligomer, polypropylene grafted with (acrylamide-acrylic acid) oligomer, polypropylene grafted with succinic anhydride oligomer, and polypropylene grafted with (succinyl) anhydride oligomer. One or more of polypropylene grafted with fluorescein-succinic anhydride) oligomer and modified polypropylene in which hydrogen in the polar modified molecule is replaced by methyl, ethyl or halogen atom. The polymerization degree of the oligomer is 2-20, preferably 5-10. Too high polymerization degree of the oligomer is easy to form defects in the modified layer. The combination of small molecule grafted modified polypropylene and oligomer grafted modified polypropylene is preferred.
在一些实施例中，所述第一改性聚丙烯和所述第二改性聚丙烯的接枝率g满足：0.1％≤g≤2％。。In some embodiments, the grafting ratio g of the first modified polypropylene and the second modified polypropylene satisfies: 0.1%≤g≤2%.
在一些实施例中，所述第一改性聚丙烯的熔融指数约为(3.1-4.1)g/10min/(230℃/2.16kg)，分子量分布指数约为4.5-5.6。In some embodiments, the first modified polypropylene has a melt index of about (3.1-4.1) g/10 min/(230° C./2.16 kg) and a molecular weight distribution index of about 4.5-5.6.
在一些实施例中，所述第二改性聚丙烯的熔融指数约为(3.2-4.0)g/10min/(230℃/2.16kg)，分子量分布指数约为4.5-5.6。In some embodiments, the melt index of the second modified polypropylene is about (3.2-4.0) g/10 min/(230° C./2.16 kg), and the molecular weight distribution index is about 4.5-5.6.
在一些实施例中，芯层中所述聚丙烯为未改性聚丙烯，且所述聚丙烯的熔融指数约为(3.0-3.9)g/10min/(230℃/2.16kg)，分子量分布指数约为4.5-5.2，等规度约≥97％。In some embodiments, the polypropylene in the core layer is unmodified polypropylene, and the melt index of the polypropylene is about (3.0-3.9) g/10 min/(230° C./2.16 kg), the molecular weight distribution index is about 4.5-5.2, and the isotacticity is about ≥97%.
在一些实施例中，在所述第一改性层中，所述第一改性聚丙烯的质量百分含量约≥20％。In some embodiments, in the first modified layer, the mass percentage of the first modified polypropylene is about ≥ 20%.
在一些实施例中，所述第一改性层中还包括第一聚丙烯和第一抗氧化剂；In some embodiments, the first modified layer further includes a first polypropylene and a first antioxidant;
以质量百分含量计，所述第一改性层中包括所述第一聚丙烯约0％-79.8％，所述第一改性聚丙烯约20％-99.9％以及所述第一抗氧化剂约0.1％-0.6％。In terms of mass percentage, the first modified layer includes about 0%-79.8% of the first polypropylene, about 20%-99.9% of the first modified polypropylene and about 0.1%-0.6% of the first antioxidant.
在一些实施例中，所述第一聚丙烯的熔融指数约为(3.0-3.9)g/10min/(230℃/2.16kg)，分子量分布指数约为4.5-5.2，等规度约为89％-97％。In some embodiments, the first polypropylene has a melt index of about (3.0-3.9) g/10 min/(230° C./2.16 kg), a molecular weight distribution index of about 4.5-5.2, and an isotacticity of about 89%-97%.
在一些实施例中，所述第一抗氧化剂选自亚磷酸三苯酯、丁基羟基茴香醚、2,6-二叔丁基-4-甲基苯酚和对叔丁基邻苯二酚中的一种或多种。In some embodiments, the first antioxidant is selected from one or more of triphenyl phosphite, butylated hydroxyanisole, 2,6-di-tert-butyl-4-methylphenol, and p-tert-butylcatechol.
在一些实施例中，在所述第二改性层中，所述第二改性聚丙烯的质量百分 含量约≥20％。In some embodiments, in the second modified layer, the mass percentage of the second modified polypropylene is The content is approximately ≥20%.
在一些实施例中，所述第二改性层中还包括第二聚丙烯和第二抗氧化剂；In some embodiments, the second modified layer further includes a second polypropylene and a second antioxidant;
以质量百分含量计，所述第二改性层中包括所述第二聚丙烯约0％-79.8％，所述第二改性聚丙烯约20％-99.9％以及所述第二抗氧化剂约0.1％-0.6％。In terms of mass percentage, the second modified layer includes about 0%-79.8% of the second polypropylene, about 20%-99.9% of the second modified polypropylene and about 0.1%-0.6% of the second antioxidant.
在一些实施例中，所述第二聚丙烯的熔融指数约为(3.0-3.9)g/10min/(230℃/2.16kg)，分子量分布指数约为4.5-5.2，等规度约为89％-97％。In some embodiments, the second polypropylene has a melt index of about (3.0-3.9) g/10 min/(230° C./2.16 kg), a molecular weight distribution index of about 4.5-5.2, and an isotacticity of about 89%-97%.
在一些实施例中，所述第一聚丙烯的等规度与芯层中所述聚丙烯的等规度的差值约1％-8％，优选为2％-8％。In some embodiments, the difference between the isotacticity of the first polypropylene and the isotacticity of the polypropylene in the core layer is about 1%-8%, preferably 2%-8%.
在一些实施例中，所述第二抗氧化剂选自亚磷酸三苯酯、丁基羟基茴香醚、2,6-二叔丁基-4-甲基苯酚和对叔丁基邻苯二酚中的一种或多种。In some embodiments, the second antioxidant is selected from one or more of triphenyl phosphite, butylated hydroxyanisole, 2,6-di-tert-butyl-4-methylphenol and p-tert-butylcatechol.
在一些实施例中，所述芯层还包括第三抗氧化剂；In some embodiments, the core layer further comprises a third antioxidant;
以质量百分含量计，所述芯层中包括所述聚丙烯约99.5％-99.8％以及第三抗氧化剂约0.2％-0.5％。In terms of mass percentage, the core layer includes about 99.5%-99.8% of the polypropylene and about 0.2%-0.5% of the third antioxidant.
在一些实施例中，所述芯层由未改性聚丙烯与第三抗氧化剂组成；In some embodiments, the core layer is composed of unmodified polypropylene and a third antioxidant;
以质量百分含量计，所述芯层中包括所述聚丙烯约99.5％-99.8％以及第三抗氧化剂约0.2％-0.5％。In terms of mass percentage, the core layer includes about 99.5%-99.8% of the polypropylene and about 0.2%-0.5% of the third antioxidant.
在一些实施例中，所述第三抗氧化剂选自亚磷酸三苯酯、丁基羟基茴香醚、2,6-二叔丁基-4-甲基苯酚和对叔丁基邻苯二酚中的一种或多种。In some embodiments, the third antioxidant is selected from one or more of triphenyl phosphite, butylated hydroxyanisole, 2,6-di-tert-butyl-4-methylphenol, and p-tert-butylcatechol.
在一些实施例中，所述多层复合聚丙烯材料的厚度约≥1μm，其中，所述第一改性层和第二改性层的厚度占比分别独立约为5％-15％，所述芯层的厚度占比约为70％-90％。In some embodiments, the thickness of the multi-layer composite polypropylene material is about ≥1 μm, wherein the thickness of the first modified layer and the second modified layer account for about 5%-15% respectively, and the thickness of the core layer accounts for about 70%-90%.
本申请还提供如上所述的多层复合聚丙烯材料的制备方法。技术方案如下：The present application also provides a method for preparing the multi-layer composite polypropylene material as described above. The technical solution is as follows:
(1)一种如上所述的多层复合聚丙烯材料的制备方法，包括如下步骤： (1) A method for preparing the multilayer composite polypropylene material as described above comprises the following steps:
在约200-260℃条件下熔融包含所述第一改性聚丙烯的原料，在约230-260℃条件下挤出制备第一改性层中间体；Melting the raw material containing the first modified polypropylene at a temperature of about 200-260° C., and extruding at a temperature of about 230-260° C. to prepare a first modified layer intermediate;
在约200-260℃条件下熔融包含所述聚丙烯的原料，在约230-260℃条件下挤出制备芯层中间体；Melting the raw material containing the polypropylene at a temperature of about 200-260° C., and extruding at a temperature of about 230-260° C. to prepare a core layer intermediate;
在约200-260℃条件下熔融包含所述第二改性聚丙烯的原料，在约230-260℃条件下挤出制备第二改性层中间体；Melting the raw material containing the second modified polypropylene at a temperature of about 200-260° C., and extruding at a temperature of about 230-260° C. to prepare a second modified layer intermediate;
在约15-60℃条件下通过制片工艺将所述第一改性层中间体、芯层中间体和第二改性层中间体复合成型制备多层复合聚丙烯材料中间体；The first modified layer intermediate, the core layer intermediate and the second modified layer intermediate are composite-molded by a sheet-making process at about 15-60° C. to prepare a multi-layer composite polypropylene material intermediate;
对所述多层复合聚丙烯材料中间体进行同步拉伸处理制备所述多层复合聚丙烯材料，且纵向总拉伸比约为5-9倍、横向总拉伸比约为4-8倍。The multi-layer composite polypropylene material intermediate is subjected to synchronous stretching treatment to prepare the multi-layer composite polypropylene material, and the total longitudinal stretching ratio is about 5-9 times and the total transverse stretching ratio is about 4-8 times.
在其中一个实施例中，所述同步拉伸包括如下步骤：In one embodiment, the synchronous stretching comprises the following steps:
逐步升温，分别在约152-157℃、约156-160℃、约159-162℃条件下对所述多层复合聚丙烯材料中间体进行第一拉伸处理、第二拉伸处理和第三拉伸处理，制备多层复合聚丙烯材料中间体I；gradually raising the temperature to perform a first stretching treatment, a second stretching treatment and a third stretching treatment on the multilayer composite polypropylene material intermediate at about 152-157° C., about 156-160° C. and about 159-162° C., respectively, to prepare a multilayer composite polypropylene material intermediate I;
逐步升温，分别在约162-165℃、约162-169℃条件下对所述多层复合聚丙烯材料中间体I进行第一热定型处理和第二热定型处理，制备所述多层复合聚丙烯材料；gradually raising the temperature to perform a first heat setting treatment and a second heat setting treatment on the multilayer composite polypropylene material intermediate I at about 162-165° C. and about 162-169° C., respectively, to prepare the multilayer composite polypropylene material;
(2)一种如上所述的多层复合聚丙烯材料的制备方法，包括如下步骤：(2) A method for preparing the multilayer composite polypropylene material as described above, comprising the following steps:
在约200-260℃条件下熔融包含所述第一改性聚丙烯的原料，在约230-260℃条件下挤出制备第一改性层中间体；Melting the raw material containing the first modified polypropylene at a temperature of about 200-260° C., and extruding at a temperature of about 230-260° C. to prepare a first modified layer intermediate;
在约200-260℃条件下熔融包含所述聚丙烯的原料，在约230-260℃条件下挤出制备芯层中间体；Melting the raw material containing the polypropylene at a temperature of about 200-260° C., and extruding at a temperature of about 230-260° C. to prepare a core layer intermediate;
在约200-260℃条件下熔融包含所述第二改性聚丙烯的原料，在约 230-260℃条件下挤出制备第二改性层中间体；The raw material comprising the second modified polypropylene is melted at about 200-260° C., Extrusion at 230-260° C. to prepare a second modified layer intermediate;
在约15-60℃条件下通过制片工艺将所述第一改性层中间体、芯层中间体和第二改性层中间体复合成型制备多层复合聚丙烯材料中间体；The first modified layer intermediate, the core layer intermediate and the second modified layer intermediate are composite-molded by a sheet-making process at about 15-60° C. to prepare a multi-layer composite polypropylene material intermediate;
对所述多层复合聚丙烯材料中间体进行异步拉伸处理制备所述多层复合聚丙烯材料，且纵向总拉伸比约为5-9倍、横向总拉伸比约为4-8倍。The multi-layer composite polypropylene material intermediate is subjected to asynchronous stretching treatment to prepare the multi-layer composite polypropylene material, and the total longitudinal stretching ratio is about 5-9 times and the total transverse stretching ratio is about 4-8 times.
在其中一个实施例中，所述异步拉伸包括如下步骤：In one embodiment, the asynchronous stretching comprises the following steps:
在约145-155℃条件下对所述多层复合聚丙烯材料中间体进行纵向拉伸处理，制备多层复合聚丙烯材料中间体II；Performing a longitudinal stretching treatment on the multi-layer composite polypropylene material intermediate at a temperature of about 145-155° C. to prepare a multi-layer composite polypropylene material intermediate II;
在约150-160℃条件下对所述多层复合聚丙烯材料II中间体进行横向拉伸处理，制备多层复合聚丙烯材料中间体III；Performing a transverse stretching treatment on the multilayer composite polypropylene material II intermediate at about 150-160° C. to prepare a multilayer composite polypropylene material intermediate III;
在约165-170℃条件下对所述多层复合聚丙烯材料III进行热成型处理，制备多层复合聚丙烯材料IV；Performing a thermoforming treatment on the multi-layer composite polypropylene material III at a temperature of about 165-170° C. to prepare a multi-layer composite polypropylene material IV;
在约120-135℃条件下对所述多层复合聚丙烯材料IV进行热处理，制备所述多层复合聚丙烯材料。The multi-layer composite polypropylene material IV is heat-treated at about 120-135° C. to prepare the multi-layer composite polypropylene material.
本申请还提供一种复合集流体，其结构包括呈层叠设置的第一保护层，第一金属层，支撑层，第二金属层和第二保护层；The present application also provides a composite current collector, the structure of which includes a first protective layer, a first metal layer, a support layer, a second metal layer and a second protective layer arranged in layers;
所述支撑层包括根据如上所述的复合聚丙烯材料。The support layer comprises a composite polypropylene material according to above.
在其中一个实施例中，所述第一保护层和第二保护层分别独立包括：不活泼金属及其合金、金属氧化物和碳材料中的一种或多种；In one embodiment, the first protective layer and the second protective layer independently include: one or more of an inactive metal and its alloy, a metal oxide and a carbon material;
所述第一金属层和第二金属层分别独立包括电阻率约≤8×10-8Ω·m的金属及其合金。The first metal layer and the second metal layer independently include metals and alloys thereof with a resistivity of about ≤8×10-8Ω·m.
在其中一个实施例中，不活泼金属选自镍和/或铬。不活泼金属合金选自镍基合金、铬基合金和镍铬铜合金中的一种或多种。金属氧化物选自氧化铜、氧 化铝、氧化镍、氧化铬、氧化钴和铜铬氧化物中的一种或多种。碳材料选自石墨、炭黑、乙炔黑、科琴黑、碳纳米量子点、碳纳米管、碳纳米纤维和石墨烯中的一种或多种。In one embodiment, the inactive metal is selected from nickel and/or chromium. The inactive metal alloy is selected from one or more of a nickel-based alloy, a chromium-based alloy, and a nickel-chromium-copper alloy. The metal oxide is selected from copper oxide, The carbon material is selected from one or more of aluminum oxide, nickel oxide, chromium oxide, cobalt oxide and copper chromium oxide. The carbon material is selected from one or more of graphite, carbon black, acetylene black, Ketjen black, carbon nano quantum dots, carbon nanotubes, carbon nanofibers and graphene.
在其中一个实施例中，电阻率约≤8×10-8Ω·m的金属选自铜、铝、银、金、锌、钼、钴、镍中的一种或多种，符合要求的合金选自铜合金、铝合金和镍合金中的一种或多种。In one embodiment, the metal with a resistivity of about ≤8×10-8Ω·m is selected from one or more of copper, aluminum, silver, gold, zinc, molybdenum, cobalt, and nickel, and the alloy that meets the requirements is selected from one or more of copper alloys, aluminum alloys, and nickel alloys.
本申请还提供一种极片，包括如上所述的复合集流体。The present application also provides a pole piece, comprising the composite current collector as described above.
本申请还提供一种电池，包括如上所述的极片。The present application also provides a battery, comprising the pole piece as described above.
本申请的一个或多个实施例的细节在下面的附图和描述中提出。本申请的其它特征、目的和优点将从说明书、附图以及权利要求书变得明显。The details of one or more embodiments of the present application are set forth in the following drawings and description. Other features, objects, and advantages of the present application will become apparent from the description, drawings, and claims.
附图说明BRIEF DESCRIPTION OF THE DRAWINGS
为了更好地描述和说明这里公开的那些发明的实施例和/或示例，可以参考一幅或多幅附图。用于描述附图的附加细节或示例不应当被认为是对所公开的发明、目前描述的实施例和/或示例以及目前理解的这些发明的最佳模式中的任何一者的范围的限制。In order to better describe and illustrate the embodiments and/or examples of the inventions disclosed herein, reference may be made to one or more drawings. The additional details or examples used to describe the drawings should not be considered as limiting the scope of the disclosed inventions, the embodiments and/or examples currently described, and any of the best modes of these inventions currently understood.
图1是根据一个或多个实施例提供的多层复合聚丙烯材料的结构示意图；FIG1 is a schematic diagram of the structure of a multilayer composite polypropylene material provided according to one or more embodiments;
图2是根据一个或多个实施例提供的多层复合聚丙烯材料的制备方法流程图；FIG2 is a flow chart of a method for preparing a multilayer composite polypropylene material according to one or more embodiments;
图3是根据一个或多个实施例提供的多层复合聚丙烯材料的制备方法流程图；FIG3 is a flow chart of a method for preparing a multilayer composite polypropylene material according to one or more embodiments;
图4是根据一个或多个实施例提供的复合集流体的结构示意图；FIG4 is a schematic diagram of the structure of a composite current collector according to one or more embodiments;
图5是根据一个或多个实施例提供的复合集流体样品为电池的电极集流体，所测得的能量密度随循环次数变化的结果示意图。 FIG5 is a schematic diagram showing the result of measuring energy density varying with cycle number when the composite current collector sample provided according to one or more embodiments is an electrode current collector of a battery.
具体实施方式Detailed ways
以下结合具体实施例对本发明作进一步详细的说明。本发明可以以许多不同的形式来实现，并不限于本文所描述的实施方式。相反地，提供这些实施方式的目的是使对本发明公开内容理解更加透彻全面。The present invention will be further described in detail below in conjunction with specific embodiments. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly understood.
除非另有定义，本文所使用的所有的技术和科学术语与属于本发明的技术领域的技术人员通常理解的含义相同。本文中在本发明的说明书中所使用的术语只是为了描述具体的实施例的目的，不是旨在于限制本发明。本文所使用的术语“和/或”包括一个或多个相关的所列项目的任意的和所有的组合。Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and/or" used herein includes any and all combinations of one or more related listed items.
在本发明中，以开放式描述的技术特征中，包括所列举特征组成的封闭式技术方案，也包括包含所列举特征的开放式技术方案。In the present invention, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.
在本发明中，涉及到数值区间，如无特别说明，上述数值区间内视为连续，且包括该范围的最小值及最大值，以及这种最小值与最大值之间的每一个值。进一步地，当范围是指整数时，包括该范围的最小值与最大值之间的每一个整数。此外，当提供多个范围描述特征或特性时，可以合并该范围。换言之，除非另有指明，否则本文中所公开之所有范围应理解为包括其中所归入的任何及所有的子范围。In the present invention, when it comes to numerical ranges, unless otherwise specified, the above numerical ranges are considered continuous and include the minimum and maximum values of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.
本发明仅具体地公开了一些数值范围。然而，任意下限可以与任意上限组合形成未明确记载的范围；以及任意下限可以与其它下限组合形成未明确记载的范围，同样任意上限可以与任意其它上限组合形成未明确记载的范围。此外，每个单独公开的点或单个数值自身可以作为下限或上限与任意其它点或单个数值组合或与其它下限或上限组合形成未明确记载的范围。The present invention only specifically discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, and any upper limit can be combined with any other upper limit to form an unspecified range. In addition, each separately disclosed point or single value can itself be combined as a lower limit or upper limit with any other point or single value or with other lower limits or upper limits to form an unspecified range.
本发明中的温度参数，如无特别限定，既允许为恒温处理，也允许在一定温度区间内进行处理。所述的恒温处理允许温度在仪器控制的精度范围内进行 波动。The temperature parameters in the present invention, if not specifically limited, allow both constant temperature treatment and treatment within a certain temperature range. The constant temperature treatment allows the temperature to be within the precision range controlled by the instrument. fluctuation.
在本发明中，涉及数据范围的单位，如果仅在右端点后带有单位，则表示左端点和右端点的单位是相同的。比如，150-160℃表示左端点“150和右端点“160”的单位都是℃(摄氏度)。In the present invention, when it comes to the unit of the data range, if there is a unit only after the right endpoint, it means that the units of the left endpoint and the right endpoint are the same. For example, 150-160°C means that the units of the left endpoint "150" and the right endpoint "160" are both ℃ (degrees Celsius).
在本发明中，术语“第一”、“第二”仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有“第一”、“第二”的特征可以明示或者隐含地包括至少一个该特征。在发明的描述中，“多种”的含义是至少两种，例如两种，三种等，除非另有明确具体的限定。在本申请的描述中，“若干”的含义是至少一个，例如一个，两个等，除非另有明确具体的限定。In the present invention, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the invention, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In the description of this application, the meaning of "several" is at least one, such as one, two, etc., unless otherwise clearly and specifically defined.
如果没有特别的说明，本发明的所有实施方式以及可选实施方式可以相互组合形成新的技术方案。If not otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form a new technical solution.
如果没有特别的说明，本发明的所有步骤可以顺序进行，也可以随机进行，一般是顺序进行的。例如，所述方法包括步骤(a)和(b)，表示所述方法可包括顺序进行的步骤(a)和(b)，也可以包括顺序进行的步骤(b)和(a)。例如，所述提到所述方法还可包括步骤(c)，表示步骤(c)可以任意顺序加入到所述方法，例如，所述方法可以包括按照步骤(a)、(b)和(c)，也可包括步骤(a)、(c)和(b)，也可以包括步骤(c)、(a)和(b)等。If not otherwise specified, all steps of the present invention may be performed sequentially or randomly, and are generally performed sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.
需要说明的是，在本发明的描述中，对于方位词，如有术语“中心”、“横向”、“纵向”、“长度”、“宽度”、“厚度”、“上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”、“底”、内”、“外”、“顺时针”、“逆时针”等指示方位和位置关系为基于附图所示的方位或位置关系，仅是为了便于叙述本发明和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定方位构造和 操作，不能理解为限制本发明的具体保护范围。It should be noted that in the description of the present invention, directional words such as the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicating directions and positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and used in a specific direction. Operations should not be construed as limiting the specific protection scope of the present invention.
在描述位置关系时，除非另有规定，否则当一元件例如层、膜或基板被指为在另一膜层“上”时，其能直接在其他膜层上或亦可存在中间膜层。进一步说，当层被指为在另一层“下”时，其可直接在下方，亦可存在一或多个中间层。亦可以理解的是，当层被指为在两层“之间”时，其可为两层之间的唯一层，或亦可存在一或多个中间层。When describing positional relationships, unless otherwise specified, when an element such as a layer, film, or substrate is referred to as being "on" another film layer, it can be directly on the other film layer or there can be an intermediate film layer. Further, when a layer is referred to as being "under" another layer, it can be directly below or there can be one or more intermediate layers. It is also understood that when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or there can be one or more intermediate layers.
在使用本文中描述的“包括”、“具有”、和“包含”的情况下，意图在于覆盖不排他的包含，除非使用了明确的限定用语，例如“仅”、“由……组成”等，否则还可以添加另一部件。Where “including,” “having,” and “comprising” are used herein, it is intended to cover a non-exclusive inclusion, and another component may also be added unless explicit limiting terms such as “only,” “consisting of,” etc. are used.
除非相反地提及，否则单数形式的术语可以包括复数形式，并不能理解为其数量为一个。Unless mentioned to the contrary, terms in the singular may include plural forms and should not be construed as being one in number.
此外，附图并不是以1：1的比例绘制，并且各元件的相对尺寸在附图中仅以示例地绘制，以便于理解本发明，但不一定按照真实比例绘制，附图中的比例不构成对本发明的限制。In addition, the drawings are not drawn in a 1:1 ratio, and the relative sizes of the elements are drawn in the drawings only as examples to facilitate understanding of the present invention, but are not necessarily drawn in true proportion. The proportions in the drawings do not constitute a limitation to the present invention.
在本发明中，接枝率指接枝到聚丙烯上的极性单体的质量与接枝后聚丙烯的质量比。In the present invention, the grafting ratio refers to the ratio of the mass of the polar monomer grafted onto the polypropylene to the mass of the grafted polypropylene.
在本发明中，等规度依据GB/T 2412-2008标准测试而得。In the present invention, the isotacticity is obtained by testing according to GB/T 2412-2008 standard.
在本发明中，横向拉伸比是指拉伸后的材料相对于未拉伸前的材料在横向方向(或宽度)的伸长倍数，纵向拉伸比是指拉伸后的材料相对于未拉伸前的材料在纵向方向(或长度)的伸长倍数。In the present invention, the transverse stretch ratio refers to the elongation multiple of the stretched material in the transverse direction (or width) relative to the unstretched material, and the longitudinal stretch ratio refers to the elongation multiple of the stretched material in the longitudinal direction (or length) relative to the unstretched material.
虽然基于聚丙烯膜的复合集流体具备成本低、质量轻、内部绝缘性好等特点，但聚丙烯膜自身材料极性较弱，导致其表面张力较低，低表面张力的聚丙烯膜与高表面张力的金属层之间的亲合力较差，从而引发二者界面之间的附着 力较低，结合不牢固，即存在表面粘附性能差的问题，以及表面张力不稳定的问题。Although the composite current collector based on polypropylene film has the characteristics of low cost, light weight, and good internal insulation, the material polarity of the polypropylene film itself is weak, resulting in low surface tension. The affinity between the low surface tension polypropylene film and the high surface tension metal layer is poor, which causes adhesion between the two interfaces. The force is low and the bonding is not strong, that is, there is a problem of poor surface adhesion and unstable surface tension.
对此，本发明提供了一种表面张力高且存储稳定性好，与金属亲和力强，且能牢固结合在一起的多层复合聚丙烯材料。In this regard, the present invention provides a multi-layer composite polypropylene material which has high surface tension, good storage stability, strong affinity with metals, and can be firmly bonded together.
技术方案如下：The technical solution is as follows:
一种多层复合聚丙烯材料，其结构包括呈层叠设置的第一改性层，芯层和第二改性层；A multi-layer composite polypropylene material, the structure of which comprises a first modified layer, a core layer and a second modified layer which are stacked;
所述第一改性层包括第一改性聚丙烯；The first modified layer includes a first modified polypropylene;
所述芯层包括聚丙烯；The core layer comprises polypropylene;
所述第二改性层包括第二改性聚丙烯；The second modified layer includes a second modified polypropylene;
所述第一改性聚丙烯和第二改性聚丙烯分别独立选自：The first modified polypropylene and the second modified polypropylene are independently selected from:
小分子接枝改性的聚丙烯：顺丁烯二酸酐接枝改性的聚丙烯、丙烯酸-顺丁烯二酸酐接枝改性的聚丙烯、二乙烯三胺-甲基丙烯酸缩水甘油酯接枝改性的聚丙烯、丙烯酰胺接枝改性的聚丙烯、丙烯酰胺-丙烯酸接枝改性聚丙烯、琥珀酸酐接枝聚丙烯、琥珀酰荧光素-琥珀酸酐接枝的聚丙烯和极性改性分子中的氢被甲基、乙基或卤素原子取代的改性聚丙烯中的一种或多种；Small molecule grafted modified polypropylene: one or more of maleic anhydride grafted modified polypropylene, acrylic acid-maleic anhydride grafted modified polypropylene, diethylenetriamine-glycidyl methacrylate grafted modified polypropylene, acrylamide grafted modified polypropylene, acrylamide-acrylic acid grafted modified polypropylene, succinic anhydride grafted polypropylene, succinylfluorescein-succinic anhydride grafted polypropylene and modified polypropylene in which hydrogen in the polar modified molecule is replaced by methyl, ethyl or halogen atoms;
低聚物接枝改性的聚丙烯：顺丁烯二酸酐低聚物接枝改性的聚丙烯、(丙烯酸-顺丁烯二酸酐)低聚物接枝改性的聚丙烯、甲基丙烯酸缩水甘油酯低聚物接枝改性的聚丙烯、二(乙烯三胺-甲基丙烯酸缩水甘油酯)低聚物接枝改性的聚丙烯、丙烯酰胺低聚物接枝改性的聚丙烯、(丙烯酰胺-丙烯酸)低聚物接枝改性聚丙烯、琥珀酸酐接枝聚丙烯、(琥珀酰荧光素-琥珀酸酐)低聚物接枝的聚丙烯和极性改性分子中的氢被甲基、乙基或卤素原子取代的改性聚丙烯中的一种或多种。其中低聚物的聚合度为2-20，优选5-10。低聚物聚合物度过高易在改性 层形成缺陷。优选小分子接枝改性的聚丙烯与低聚物接枝改性的聚丙烯的组合物。Oligomer grafted polypropylene: polypropylene grafted with maleic anhydride oligomers, polypropylene grafted with (acrylic acid-maleic anhydride) oligomers, polypropylene grafted with glycidyl methacrylate oligomers, polypropylene grafted with di(ethylenetriamine-glycidyl methacrylate) oligomers, polypropylene grafted with acrylamide oligomers, (acrylamide-acrylic acid) oligomers, succinic anhydride grafted polypropylene, (succinylfluorescein-succinic anhydride) oligomers, and one or more of modified polypropylenes in which hydrogen in the polar modified molecule is replaced by methyl, ethyl or halogen atoms. The degree of polymerization of the oligomer is 2-20, preferably 5-10. Too high a polymerization degree of the oligomer is easy to cause polymerization in the modified The composition of small molecule graft-modified polypropylene and oligomer graft-modified polypropylene is preferred.
相比于未改性聚丙烯，经极性分子改性的聚丙烯具有更大的极性和表面张力。本发明通过在多层复合聚丙烯材料的表层中加入经极性分子改性的聚丙烯，在保证多层复合聚丙烯材料的拉伸强度满足应用于集流体的性能要求的前提下，有效地提升了复合聚丙烯材料的表面极性，进而提升了其表面张力。进一步地，经极性分子改性的聚丙烯不易结晶，且能够抑制聚丙烯的结晶，提升自由体积。通过改性层(表层)表面张力和自由体积的提升共同促进了复合聚丙烯材料的表面粘附性能，与金属结合力强，能与金属牢固地结合在一起。并且，由于改性聚丙烯中极性分子与聚丙烯是通过共价键连接，结构稳定，从而使得表层表面张力稳定，存储过程中不会发生表面张力的衰减，表现出优异的存储稳定性。故，若以本申请制备的复合聚丙烯材料作为复合集流体的基材，能与金属层牢固粘结，提升电池性能。Compared with unmodified polypropylene, polypropylene modified by polar molecules has greater polarity and surface tension. The present invention effectively improves the surface polarity of the composite polypropylene material and thus improves its surface tension by adding polypropylene modified by polar molecules to the surface layer of the multilayer composite polypropylene material, while ensuring that the tensile strength of the multilayer composite polypropylene material meets the performance requirements of the current collector. Furthermore, the polypropylene modified by polar molecules is not easy to crystallize, and can inhibit the crystallization of polypropylene and increase the free volume. The surface adhesion performance of the composite polypropylene material is jointly promoted by the increase of the surface tension and free volume of the modified layer (surface layer), and the metal bonding force is strong, and it can be firmly combined with the metal. In addition, since the polar molecules and polypropylene in the modified polypropylene are connected by covalent bonds, the structure is stable, so that the surface tension of the surface layer is stable, and the surface tension will not decay during the storage process, showing excellent storage stability. Therefore, if the composite polypropylene material prepared in this application is used as the substrate of the composite current collector, it can be firmly bonded to the metal layer to improve the battery performance.
图1是本发明其中一实施例制得的复合聚丙烯材料的结构示意图，其中101表示第一改性层，102表示芯层，103表示第二改性层。FIG1 is a schematic diagram of the structure of a composite polypropylene material prepared according to one embodiment of the present invention, wherein 101 represents a first modified layer, 102 represents a core layer, and 103 represents a second modified layer.
可以理解地，在本发明中，第一改性层和第二改性层的作用相同，但第一改性层和第二改性层中的材料种类以及含量可以相同也可以不同。It can be understood that in the present invention, the first modified layer and the second modified layer have the same function, but the material types and contents in the first modified layer and the second modified layer can be the same or different.
在其中一个实施例中，所述芯层不包含改性的聚丙烯。本发明的发明人发现，芯层不包含改性的聚丙烯可以保证多层复合聚丙烯材料满足复合集流体的力学性能要求，比如拉伸强度等。In one embodiment, the core layer does not contain modified polypropylene. The inventors of the present invention have found that the core layer does not contain modified polypropylene, which can ensure that the multi-layer composite polypropylene material meets the mechanical property requirements of the composite current collector, such as tensile strength.
在本发明中，经极性分子改性的第一改性聚丙烯和第二改性聚丙烯分别独立地选自：顺丁烯二酸酐接枝改性的聚丙烯、丙烯酸-顺丁烯二酸酐接枝改性的聚丙烯、二乙烯三胺-甲基丙烯酸缩水甘油酯接枝改性的聚丙烯、丙烯酰胺接枝 改性的聚丙烯、丙烯酰胺-丙烯酸接枝改性聚丙烯、琥珀酸酐接枝聚丙烯、琥珀酰荧光素-琥珀酸酐接枝的聚丙烯和极性改性分子中的氢被甲基、乙基或卤素原子取代的改性聚丙烯中的一种或多种，顺丁烯二酸酐低聚物接枝改性的聚丙烯、(丙烯酸-顺丁烯二酸酐)低聚物接枝改性的聚丙烯、甲基丙烯酸缩水甘油酯低聚物接枝改性的聚丙烯、二(乙烯三胺-甲基丙烯酸缩水甘油酯)低聚物接枝改性的聚丙烯、丙烯酰胺低聚物接枝改性的聚丙烯、(丙烯酰胺-丙烯酸)低聚物接枝改性聚丙烯、琥珀酸酐低聚物接枝聚丙烯、(琥珀酰荧光素-琥珀酸酐)低聚物接枝的聚丙烯和极性改性分子中的氢被甲基、乙基或卤素原子取代的改性聚丙烯中的一种或多种。采用这样的改性聚丙烯能够更好地提升聚丙烯的极性，提高表面张力以及存储稳定性。可以理解地，在本发明中，第一改性聚丙烯和第二改性聚丙烯的种类可以相同也可以不同。In the present invention, the first modified polypropylene and the second modified polypropylene modified by polar molecules are independently selected from: polypropylene grafted with maleic anhydride, polypropylene grafted with acrylic acid and maleic anhydride, polypropylene grafted with diethylenetriamine and glycidyl methacrylate, polypropylene grafted with acrylamide, One or more of modified polypropylene, acrylamide-acrylic acid grafted modified polypropylene, succinic anhydride grafted polypropylene, succinylfluorescein-succinic anhydride grafted polypropylene, and modified polypropylene in which hydrogen in polar modified molecules is replaced by methyl, ethyl or halogen atoms, maleic anhydride oligomer grafted modified polypropylene, (acrylic acid-maleic anhydride) oligomer grafted modified polypropylene, methacrylate glycidyl oligomer grafted modified polypropylene, di(ethylenetriamine-methacrylate glycidyl) oligomer grafted modified polypropylene, acrylamide oligomer grafted modified polypropylene, (acrylamide-acrylic acid) oligomer grafted modified polypropylene, succinic anhydride oligomer grafted polypropylene, (succinylfluorescein-succinic anhydride) oligomer grafted polypropylene, and modified polypropylene in which hydrogen in polar modified molecules is replaced by methyl, ethyl or halogen atoms. Using such modified polypropylene can better improve the polarity of polypropylene, improve surface tension and storage stability. It can be understood that, in the present invention, the types of the first modified polypropylene and the second modified polypropylene can be the same or different.
本发明的发明人发现，聚丙烯分子中的极性分子含量增加，可引起第一改性层和第二改性层的表面张力呈现增大的趋势；极性分子在聚丙烯分子中一方面起到扰乱分子排列规整性的作用，另一方面又起到结晶成核的作用，二者相互制约，影响自由体积。另外，接枝率的高低还会影响材料的成膜性和表面缺陷，进而影响良品率。可以理解地，所述第一改性聚丙烯和第二改性聚丙烯的接枝率可以相同也可以不同。The inventors of the present invention have found that the increase in the content of polar molecules in the polypropylene molecules can cause the surface tension of the first modified layer and the second modified layer to show an increasing trend; polar molecules in the polypropylene molecules play a role in disrupting the regularity of molecular arrangement on the one hand, and on the other hand, they play a role in crystallization nucleation, and the two restrict each other and affect the free volume. In addition, the grafting rate will also affect the film forming properties and surface defects of the material, and thus affect the yield rate. It can be understood that the grafting rates of the first modified polypropylene and the second modified polypropylene can be the same or different.
在一些实施例中，所述第一改性聚丙烯和所述第二改性聚丙烯的接枝率均约≥0.1％，包括但不限于为：0.1％、0.2％、0.3％、0.4％、0.5％、0.6％、0.7％、0.8％、0.9％、1.0％、1.1％、1.2％、1.3％、1.4％、1.5％或1.6％。In some embodiments, the grafting rates of the first modified polypropylene and the second modified polypropylene are both approximately ≥0.1%, including but not limited to: 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5% or 1.6%.
在一些实施例中，所述第一改性聚丙烯和所述第二改性聚丙烯的接枝率分别独立约为0.2％-1.5％，这样能够协同提高复合聚丙烯的表面张力和自由体积，进而提高其与金属的结合力。接枝率过高会增加分支结构的密度，使聚丙烯的 晶体区域减少，从而影响其硬度、强度和刚性等物理性能，导致改性层易产生缺陷。接枝率过低则第一改性层或第二改性层的极性、表面张力及自由体积提升有限。In some embodiments, the grafting rates of the first modified polypropylene and the second modified polypropylene are respectively about 0.2%-1.5%, which can synergistically improve the surface tension and free volume of the composite polypropylene, thereby improving its bonding strength with the metal. The crystal area is reduced, thus affecting its physical properties such as hardness, strength and rigidity, resulting in defects in the modified layer. If the grafting rate is too low, the polarity, surface tension and free volume of the first modified layer or the second modified layer will be limited.
本发明的发明人发现，改变第一改性层和/或第二改性层中改性聚丙烯的熔融指数，能够调控改性层的表面张力和自由体积，成膜性和力学性能。可以理解地，所述第一改性聚丙烯和第二改性聚丙烯的熔融指数可以相同也可以不同。The inventors of the present invention have found that changing the melt index of the modified polypropylene in the first modified layer and/or the second modified layer can adjust the surface tension and free volume, film forming properties and mechanical properties of the modified layer. It is understandable that the melt index of the first modified polypropylene and the second modified polypropylene can be the same or different.
在一些实施例中，所述第一改性聚丙烯的熔融指数约为(3.1-4.1)g/10min/(230℃/2.16kg)，包括但不限于为3.1g/10min、3.2g/10min、3.3g/10min、3.4g/10min、3.5g/10min、3.6g/10min、3.7g/10min、3.8g/10min、3.9g/10min、4.0g/10min和4.1g/10min。In some embodiments, the melt index of the first modified polypropylene is about (3.1-4.1) g/10min/(230°C/2.16kg), including but not limited to 3.1 g/10min, 3.2 g/10min, 3.3 g/10min, 3.4 g/10min, 3.5 g/10min, 3.6 g/10min, 3.7 g/10min, 3.8 g/10min, 3.9 g/10min, 4.0 g/10min and 4.1 g/10min.
在一些实施例中，所述第一改性聚丙烯的熔融指数约为(3.2-4.0)g/10min/(230℃/2.16kg)，这样能够协同提高复合聚丙烯的表面张力和自由体积，进而提高其与金属的结合力，以及保证材料成膜性、良品率和力学性能。In some embodiments, the melt index of the first modified polypropylene is about (3.2-4.0) g/10 min/(230°C/2.16 kg), which can synergistically improve the surface tension and free volume of the composite polypropylene, thereby improving its bonding strength with the metal, and ensuring the film forming property, yield rate and mechanical properties of the material.
在一些实施例中，所述第二改性聚丙烯的熔融指数约为(3.1-4.1)g/10min/(230℃/2.16kg)，包括但不限于为3.1g/10min、3.2g/10min、3.3g/10min、3.4g/10min、3.5g/10min、3.6g/10min、3.7g/10min、3.8g/10min、3.9g/10min、4.0g/10min和4.1g/10min。In some embodiments, the melt index of the second modified polypropylene is about (3.1-4.1) g/10min/(230°C/2.16kg), including but not limited to 3.1 g/10min, 3.2 g/10min, 3.3 g/10min, 3.4 g/10min, 3.5 g/10min, 3.6 g/10min, 3.7 g/10min, 3.8 g/10min, 3.9 g/10min, 4.0 g/10min and 4.1 g/10min.
在一些实施例中，所述第二改性聚丙烯的熔融指数约为(3.2-4.0)g/10min/(230℃/2.16kg)，这样能够协同提高复合聚丙烯的表面张力和自由体积，进而提高其与金属的结合力，以及保证材料成膜性、良品率和力学性能。In some embodiments, the melt index of the second modified polypropylene is about (3.2-4.0) g/10 min/(230°C/2.16 kg), which can synergistically improve the surface tension and free volume of the composite polypropylene, thereby improving its bonding strength with the metal, and ensuring the film forming property, yield rate and mechanical properties of the material.
本发明的发明人发现，改变第一改性层和/或第二改性层中改性聚丙烯的分子量分布指数，也能够调控改性层的表面张力和自由体积，以及成膜性、良品率和力学性能。可以理解地，所述第一改性聚丙烯和第二改性聚丙烯的分子量 分布指数可以相同也可以不同。The inventors of the present invention have found that by changing the molecular weight distribution index of the modified polypropylene in the first modified layer and/or the second modified layer, the surface tension and free volume, as well as the film forming property, yield rate and mechanical properties of the modified layer can also be regulated. It can be understood that the molecular weight of the first modified polypropylene and the second modified polypropylene is The distribution indices can be the same or different.
在一些实施例中，所述第一改性聚丙烯的分子量分布指数约为4.5-5.6，包括但不限于为4.5、4.6、4.7、4.8、4.9、5.0、5.1、5.2、5.3、5.4、5.5和5.6。In some embodiments, the molecular weight distribution index of the first modified polypropylene is about 4.5-5.6, including but not limited to 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5 and 5.6.
在一些实施例中，所述第一改性聚丙烯的分子量分布指数约为4.6-5.5，这样能够协同提高复合聚丙烯的表面张力和自由体积，进而提高其与金属的结合力，以及保证材料成膜性、良品率和力学性能。In some embodiments, the molecular weight distribution index of the first modified polypropylene is about 4.6-5.5, which can synergistically improve the surface tension and free volume of the composite polypropylene, thereby improving its bonding strength with the metal, and ensuring the film forming property, yield rate and mechanical properties of the material.
在一些实施例中，所述第二改性聚丙烯的分子量分布指数约为4.5-5.6，包括但不限于为4.5、4.6、4.7、4.8、4.9、5.0、5.1、5.2、5.3、5.4、5.5和5.6。In some embodiments, the molecular weight distribution index of the second modified polypropylene is about 4.5-5.6, including but not limited to 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5 and 5.6.
在一些实施例中，所述第二改性聚丙烯的分子量分布指数约为4.6-5.5，这样能够协同提高复合聚丙烯的表面张力和自由体积，进而提高其与金属的结合力，以及保证材料成膜性、良品率和力学性能。In some embodiments, the molecular weight distribution index of the second modified polypropylene is about 4.6-5.5, which can synergistically improve the surface tension and free volume of the composite polypropylene, thereby improving its bonding strength with the metal, and ensuring the film forming property, yield rate and mechanical properties of the material.
参见上述描述，在改性层中添加经极性分子接枝后的改性聚丙烯，即可增加改性层的极性。本发明的发明人发现，改变第一改性层和第二改性层中改性聚丙烯的含量，能够调控改性层的表面张力和自由体积，以及材料成膜性、良品率和力学性能。As described above, adding modified polypropylene grafted with polar molecules to the modified layer can increase the polarity of the modified layer. The inventors of the present invention have found that changing the content of modified polypropylene in the first modified layer and the second modified layer can adjust the surface tension and free volume of the modified layer, as well as the film forming property, yield rate and mechanical properties of the material.
在一些实施例中，在所述第一改性层中，所述第一改性聚丙烯的质量百分含量约≥20％，包括但不限于为20％、22％、23％、24％、25％、26％、28％、30％、32％、33％、34％、36％、38％、40％、41％、42％、44％、45％、46％、48％、50％、51％、52％、55％、58％、60％、62％、65％、70％、72％、75％、80％、85％、88％、90％、92％、95％、96％、98％、99.8％、99％和100％。In some embodiments, in the first modified layer, the mass percentage of the first modified polypropylene is about ≥20%, including but not limited to 20%, 22%, 23%, 24%, 25%, 26%, 28%, 30%, 32%, 33%, 34%, 36%, 38%, 40%, 41%, 42%, 44%, 45%, 46%, 48%, 50%, 51%, 52%, 55%, 58%, 60%, 62%, 65%, 70%, 72%, 75%, 80%, 85%, 88%, 90%, 92%, 95%, 96%, 98%, 99.8%, 99% and 100%.
在一些实施例中，所述第一改性层中还包括第一聚丙烯和第一抗氧化剂。通过聚丙烯、抗氧化剂的作用，改善复合聚丙烯材料的成膜性、良品率和力学性能。 In some embodiments, the first modified layer further includes a first polypropylene and a first antioxidant. The film forming property, yield rate and mechanical properties of the composite polypropylene material are improved through the action of the polypropylene and the antioxidant.
在一些实施例中，所述第一聚丙烯的熔融指数约为(3.0-3.9)g/10min/(230℃/2.16kg)，包括但不限于为3.0g/10min、3.1g/10min、3.2g/10min、3.3g/10min、3.4g/10min、3.5g/10min、3.6g/10min、3.7g/10min、3.8g/10min和3.9g/10min。In some embodiments, the melt index of the first polypropylene is about (3.0-3.9) g/10 min/(230°C/2.16 kg), including but not limited to 3.0 g/10 min, 3.1 g/10 min, 3.2 g/10 min, 3.3 g/10 min, 3.4 g/10 min, 3.5 g/10 min, 3.6 g/10 min, 3.7 g/10 min, 3.8 g/10 min and 3.9 g/10 min.
在一些实施例中，所述第一聚丙烯的分子量分布指数约为4.5-5.2，包括但不限于为4.5、4.6、4.7、4.8、4.9、5.0、5.1和5.2。In some embodiments, the molecular weight distribution index of the first polypropylene is about 4.5-5.2, including but not limited to 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1 and 5.2.
本发明的发明人发现，聚丙烯的等规度影响改性层中高分子的排列规整性，进一步影响自由体积、结合力和粘附性能，另外还对复合聚丙烯材料的力学性能和成膜性有影响。The inventors of the present invention have found that the isotacticity of polypropylene affects the regularity of the arrangement of the polymer in the modified layer, further affecting the free volume, binding force and adhesion performance, and also affects the mechanical properties and film-forming properties of the composite polypropylene material.
在一些实施例中，所述第一聚丙烯的等规度约为89％-97％，包括但不限于为89％、90％、91％、92％、93％、94％、95％、96％和97％。In some embodiments, the isotacticity of the first polypropylene is about 89%-97%, including but not limited to 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96% and 97%.
在一些实施例中，在本发明中所述第一聚丙烯的等规度约为90％-96％，这样能够协同复合聚丙烯材料的表面张力、自由体积、力学性能、良品率和成膜性。In some embodiments, in the present invention, the isotacticity of the first polypropylene is about 90%-96%, which can synergize the surface tension, free volume, mechanical properties, yield and film-forming properties of the composite polypropylene material.
在一些实施例中，本发明所述的第一聚丙烯的等规度与所述聚丙烯的等规度的差值约为1％-8％，优选为2％-8％，这样可以使得所述第一改性层与所述芯层之间逐渐过渡，不仅可以避免应力集中问题，提高多层结构的整体强度和韧性，而且可以避免因相邻层之间性能不匹配造成界面应力而出现的降低层间剥离或开裂的风险。In some embodiments, the difference between the isotacticity of the first polypropylene described in the present invention and the isotacticity of the polypropylene is about 1%-8%, preferably 2%-8%, so that the first modified layer and the core layer can be gradually transitioned, which can not only avoid stress concentration problems and improve the overall strength and toughness of the multilayer structure, but also avoid the risk of interlayer delamination or cracking caused by interface stress caused by performance mismatch between adjacent layers.
在一些实施例中，所述第一抗氧化剂选自亚磷酸三苯酯、丁基羟基茴香醚、2,6-二叔丁基-4-甲基苯酚和对叔丁基邻苯二酚中的一种或多种。In some embodiments, the first antioxidant is selected from one or more of triphenyl phosphite, butylated hydroxyanisole, 2,6-di-tert-butyl-4-methylphenol, and p-tert-butylcatechol.
在一些实施例中，以质量百分含量计，所述第一改性层中包括所述第一聚丙烯约0％-79.8％，所述第一改性聚丙烯约20％-99.9％以及所述第一抗氧化剂约 0.1％-0.6％。In some embodiments, the first modified layer includes about 0%-79.8% of the first polypropylene, about 20%-99.9% of the first modified polypropylene, and about 1%-20% of the first antioxidant, based on mass percentage. 0.1%-0.6%.
其中，在所述第一改性层中，第一聚丙烯的含量包括但不限于为0％、2％、5％、10％、15％、20％、22％、23％、24％、25％、26％、28％、30％、32％、33％、34％、36％、38％、40％、41％、42％、44％、45％、46％、49.8％、50％、51％、52％、55％、58％、60％、62％、65％、70％、72％、75％和79.8％。Wherein, in the first modified layer, the content of the first polypropylene includes but is not limited to 0%, 2%, 5%, 10%, 15%, 20%, 22%, 23%, 24%, 25%, 26%, 28%, 30%, 32%, 33%, 34%, 36%, 38%, 40%, 41%, 42%, 44%, 45%, 46%, 49.8%, 50%, 51%, 52%, 55%, 58%, 60%, 62%, 65%, 70%, 72%, 75% and 79.8%.
在一些实施例中，以质量百分含量计，所述第一改性层中包括所述第一聚丙烯约为20％-50％。In some embodiments, based on mass percentage, the first modified layer includes about 20%-50% of the first polypropylene.
在所述第一改性层中，第一改性聚丙烯的含量包括但不限于为20％、22％、23％、24％、25％、26％、28％、30％、32％、33％、34％、36％、38％、40％、41％、42％、44％、45％、46％、48％、50％、51％、52％、55％、58％、60％、62％、65％、70％、72％、75％、80％、85％、88％、90％、92％、95％、96％、99.8％和99.9％。In the first modified layer, the content of the first modified polypropylene includes but is not limited to 20%, 22%, 23%, 24%, 25%, 26%, 28%, 30%, 32%, 33%, 34%, 36%, 38%, 40%, 41%, 42%, 44%, 45%, 46%, 48%, 50%, 51%, 52%, 55%, 58%, 60%, 62%, 65%, 70%, 72%, 75%, 80%, 85%, 88%, 90%, 92%, 95%, 96%, 99.8% and 99.9%.
在一些实施例中，以质量百分含量计，所述第一改性层中包括所述第一改性聚丙烯约为20％-99.8％。In some embodiments, based on mass percentage, the first modified layer includes about 20%-99.8% of the first modified polypropylene.
在所述第一改性层中，所述第一抗氧化剂的含量包括但不限于为0.1％、0.2％、0.3％、0.4％、0.5％和0.6％。In the first modified layer, the content of the first antioxidant includes, but is not limited to, 0.1%, 0.2%, 0.3%, 0.4%, 0.5% and 0.6%.
在一些实施例中，以质量百分含量计，所述第一改性层中包括所述第一抗氧化剂约为0.2％-0.5％。In some embodiments, the first modified layer includes about 0.2%-0.5% of the first antioxidant in terms of mass percentage.
在一些实施例中，第一改性层和第二改性层作用相同，针对第二改性层的描述可参照第一改性层，具体如下：In some embodiments, the first modified layer and the second modified layer have the same function, and the description of the second modified layer can refer to the first modified layer, as follows:
在一些实施例中，在所述第二改性层中，所述第二改性聚丙烯的质量百分含量约≥20％，包括但不限于为20％、22％、23％、24％、25％、26％、28％、30％、32％、33％、34％、36％、38％、40％、41％、42％、44％、45％、46％、48％、 50％、51％、52％、55％、58％、60％、62％、65％、70％、72％、75％、80％、85％、88％、90％、92％、95％、96％、98％、99.8％、99％和100％。In some embodiments, in the second modified layer, the mass percentage of the second modified polypropylene is about ≥20%, including but not limited to 20%, 22%, 23%, 24%, 25%, 26%, 28%, 30%, 32%, 33%, 34%, 36%, 38%, 40%, 41%, 42%, 44%, 45%, 46%, 48%, 50%, 51%, 52%, 55%, 58%, 60%, 62%, 65%, 70%, 72%, 75%, 80%, 85%, 88%, 90%, 92%, 95%, 96%, 98%, 99.8%, 99% and 100%.
在一些实施例中，在所述第一改性层中，所述第一改性聚丙烯的质量百分含量约≥20％；且在所述第二改性层中，所述第二改性聚丙烯的质量百分含量约≥20％。这样更能够协同复合聚丙烯材料的表面张力、自由体积、力学性能、良品率和成膜性。In some embodiments, in the first modified layer, the mass percentage of the first modified polypropylene is about ≥20%; and in the second modified layer, the mass percentage of the second modified polypropylene is about ≥20%. This can better coordinate the surface tension, free volume, mechanical properties, yield and film-forming properties of the composite polypropylene material.
在一些实施例中，所述第二改性层中还包括第二聚丙烯和第二抗氧化剂。通过聚丙烯、抗氧化剂的作用，改善复合聚丙烯材料的成膜性、良品率和力学性能。In some embodiments, the second modified layer further includes a second polypropylene and a second antioxidant. Through the action of the polypropylene and the antioxidant, the film forming property, the yield rate and the mechanical properties of the composite polypropylene material are improved.
在一些实施例中，所述第二聚丙烯的熔融指数约为(3.0-3.9)g/10min/(230℃/2.16kg)，包括但不限于为3.0g/10min、3.1g/10min、3.2g/10min、3.3g/10min、3.4g/10min、3.5g/10min、3.6g/10min、3.7g/10min、3.8g/10min和3.9g/10min。In some embodiments, the melt index of the second polypropylene is about (3.0-3.9) g/10 min/(230°C/2.16 kg), including but not limited to 3.0 g/10 min, 3.1 g/10 min, 3.2 g/10 min, 3.3 g/10 min, 3.4 g/10 min, 3.5 g/10 min, 3.6 g/10 min, 3.7 g/10 min, 3.8 g/10 min and 3.9 g/10 min.
在一些实施例中，所述第二聚丙烯的分子量分布指数约为4.5-5.2，包括但不限于为4.5、4.6、4.7、4.8、4.9、5.0、5.1和5.2。In some embodiments, the molecular weight distribution index of the second polypropylene is about 4.5-5.2, including but not limited to 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1 and 5.2.
在一些实施例中，所述第二聚丙烯的等规度约为89％-97％，包括但不限于为89％、90％、91％、92％、93％、94％、95％、96％和97％。In some embodiments, the isotacticity of the second polypropylene is about 89%-97%, including but not limited to 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96% and 97%.
在一些实施例中，在本发明中所述第二聚丙烯的等规度约为90％-96％，这样能够协同复合聚丙烯材料的表面张力、自由体积、力学性能、良品率和成膜性。In some embodiments, in the present invention, the isotacticity of the second polypropylene is about 90%-96%, which can synergize the surface tension, free volume, mechanical properties, yield and film-forming properties of the composite polypropylene material.
在一些实施例中，本发明所述第一聚丙烯的等规度与所述聚丙烯的等规度的差值约1％-8％，优选为2％-8％，这样可以使得所述第二改性层与所述芯层之间逐渐过渡，不仅可以避免应力集中问题，提高多层结构的整体强度和韧性， 而且可以避免因相邻层之间性能不匹配造成界面应力而出现的降低层间剥离或开裂的风险。In some embodiments, the difference between the isotacticity of the first polypropylene and the isotacticity of the polypropylene of the present invention is about 1%-8%, preferably 2%-8%, so that the second modified layer and the core layer can be gradually transitioned, which can not only avoid the problem of stress concentration, but also improve the overall strength and toughness of the multilayer structure. It can also avoid the risk of interlayer delamination or cracking caused by interface stress caused by performance mismatch between adjacent layers.
在一些实施例中，所述第二抗氧化剂选自亚磷酸三苯酯、丁基羟基茴香醚、2,6-二叔丁基-4-甲基苯酚和对叔丁基邻苯二酚中的一种或多种。In some embodiments, the second antioxidant is selected from one or more of triphenyl phosphite, butylated hydroxyanisole, 2,6-di-tert-butyl-4-methylphenol and p-tert-butylcatechol.
在一些实施例中，以质量百分含量计，所述第二改性层中包括所述第二聚丙烯约0％-79.8％，所述第二改性聚丙烯约20％-99.9％以及所述第二抗氧化剂约0.1％-0.6％。In some embodiments, based on mass percentage, the second modified layer includes about 0%-79.8% of the second polypropylene, about 20%-99.9% of the second modified polypropylene, and about 0.1%-0.6% of the second antioxidant.
其中，在所述第二改性层中，第二聚丙烯的含量包括但不限于为0％、2％、5％、10％、15％、20％、22％、23％、24％、25％、26％、28％、30％、32％、33％、34％、36％、38％、40％、41％、42％、44％、45％、46％、49.8％、50％、51％、52％、55％、58％、60％、62％、65％、70％、72％、75％和79.8％。Wherein, in the second modified layer, the content of the second polypropylene includes but is not limited to 0%, 2%, 5%, 10%, 15%, 20%, 22%, 23%, 24%, 25%, 26%, 28%, 30%, 32%, 33%, 34%, 36%, 38%, 40%, 41%, 42%, 44%, 45%, 46%, 49.8%, 50%, 51%, 52%, 55%, 58%, 60%, 62%, 65%, 70%, 72%, 75% and 79.8%.
在一些实施例中，以质量百分含量计，所述第二改性层中包括所述第二聚丙烯约为20％-50％。In some embodiments, the second modified layer includes about 20%-50% of the second polypropylene by weight.
在所述第二改性层中，第二改性聚丙烯的含量包括但不限于为20％、22％、23％、24％、25％、26％、28％、30％、32％、33％、34％、36％、38％、40％、41％、42％、44％、45％、46％、48％、50％、51％、52％、55％、58％、60％、62％、65％、70％、72％、75％、80％、85％、88％、90％、92％、95％、96％、99.8％和99.9％In the second modified layer, the content of the second modified polypropylene includes but is not limited to 20%, 22%, 23%, 24%, 25%, 26%, 28%, 30%, 32%, 33%, 34%, 36%, 38%, 40%, 41%, 42%, 44%, 45%, 46%, 48%, 50%, 51%, 52%, 55%, 58%, 60%, 62%, 65%, 70%, 72%, 75%, 80%, 85%, 88%, 90%, 92%, 95%, 96%, 99.8% and 99.9%.
在一些实施例中，以质量百分含量计，所述第二改性层中包括所述第二改性聚丙烯约为20％-99.8％。In some embodiments, the second modified layer includes about 20%-99.8% of the second modified polypropylene in terms of mass percentage.
在所述第二改性层中，所述第二抗氧化剂的含量包括但不限于为0.1％、0.2％、0.3％、0.4％、0.5％和0.6％。In the second modified layer, the content of the second antioxidant includes, but is not limited to, 0.1%, 0.2%, 0.3%, 0.4%, 0.5% and 0.6%.
在一些实施例中，以质量百分含量计，所述第二改性层中包括所述第二抗 氧化剂约为0.2％-0.5％。In some embodiments, the second modified layer includes the second anti- The oxidant is about 0.2%-0.5%.
在一些实施例中，所述芯层的聚丙烯的熔融指数约为(3.0-3.9)g/10min/(230℃/2.16kg)，包括但不限于为3.0g/10min、3.1g/10min、3.2g/10min、3.3g/10min、3.4g/10min、3.5g/10min、3.6g/10min、3.7g/10min、3.8g/10min和3.9g/10min。In some embodiments, the melt index of the polypropylene of the core layer is about (3.0-3.9) g/10min/(230°C/2.16kg), including but not limited to 3.0 g/10min, 3.1 g/10min, 3.2 g/10min, 3.3 g/10min, 3.4 g/10min, 3.5 g/10min, 3.6 g/10min, 3.7 g/10min, 3.8 g/10min and 3.9 g/10min.
在其一些实施例中，所述芯层的聚丙烯的分子量分布指数约为4.5-5.2，包括但不限于为4.5、4.6、4.7、4.8、4.8、4.9、5.0、5.1和5.2。In some embodiments thereof, the molecular weight distribution index of the polypropylene of the core layer is about 4.5-5.2, including but not limited to 4.5, 4.6, 4.7, 4.8, 4.8, 4.9, 5.0, 5.1 and 5.2.
在一些实施例中，所述芯层的聚丙烯的等规度约≥97％，包括但不限于为97％、98％、99％和100％。In some embodiments, the isotacticity of the polypropylene of the core layer is about ≥ 97%, including but not limited to 97%, 98%, 99% and 100%.
在其中一个实施例中，所述芯层还包括第三抗氧化剂。In one embodiment, the core layer further includes a third antioxidant.
在一些实施例中，所述第三抗氧化剂选自亚磷酸三苯酯、丁基羟基茴香醚、2,6-二叔丁基-4-甲基苯酚和对叔丁基邻苯二酚中的一种或多种。In some embodiments, the third antioxidant is selected from one or more of triphenyl phosphite, butylated hydroxyanisole, 2,6-di-tert-butyl-4-methylphenol, and p-tert-butylcatechol.
在一些实施例中，以质量百分含量计，所述芯层中包括所述聚丙烯约99.5％-99.8％以及第三抗氧化剂约0.2％-0.5％。In some embodiments, the core layer comprises about 99.5%-99.8% of the polypropylene and about 0.2%-0.5% of the third antioxidant, based on mass percentage.
在一些实施例中，所述多层复合聚丙烯材料的厚度约≥1μm，因此聚丙烯膜越薄越能促进复合集流体能量密度的提升，同时兼顾生产难度(膜越薄、生产难度越大、良品率越低)。在一些实施例中，所述多层复合聚丙烯材料的为约2μm-20μm。其中，在所述复合聚丙烯材料中，所述第一改性层和第二改性层的厚度占比分别独立约为5％-15％，所述芯层的厚度占比约为70％-90％。本发明的发明人发现，与现有改性聚丙烯膜方法制备的聚丙烯膜相比，本发明通过控制第一改性层、第二改性层以及芯层的厚度以及厚度占比，并通过控制第一改性层、第二改性层以及芯层中聚丙烯的等规度，大幅度提升了表面张力的稳定性的同时保证了多层复合聚丙烯材料的力学性能，解决了目前改性聚丙烯膜存 在的高表面张力与优异力学性能不能兼具的问题。In some embodiments, the thickness of the multi-layer composite polypropylene material is about ≥1 μm, so the thinner the polypropylene film is, the more it can promote the improvement of the energy density of the composite current collector, while taking into account the difficulty of production (the thinner the film, the greater the difficulty of production, and the lower the yield rate). In some embodiments, the thickness of the multi-layer composite polypropylene material is about 2μm-20μm. Among them, in the composite polypropylene material, the thickness proportions of the first modified layer and the second modified layer are independently about 5%-15%, and the thickness proportion of the core layer is about 70%-90%. The inventors of the present invention have found that compared with the polypropylene film prepared by the existing modified polypropylene film method, the present invention greatly improves the stability of the surface tension while ensuring the mechanical properties of the multi-layer composite polypropylene material by controlling the thickness and thickness proportion of the first modified layer, the second modified layer and the core layer, and by controlling the isotacticity of the polypropylene in the first modified layer, the second modified layer and the core layer, thereby solving the current problems of modified polypropylene film. The problem is that high surface tension and excellent mechanical properties cannot be achieved at the same time.
在一些实施例中，所述多层复合聚丙烯材料的自由体积分数为0.018-0.04。这样可以增强金属层与多层复合聚丙烯材料之间的粘结力。In some embodiments, the free volume fraction of the multi-layer composite polypropylene material is 0.018-0.04, which can enhance the bonding force between the metal layer and the multi-layer composite polypropylene material.
本发明还提供如上所述的多层复合聚丙烯材料的制备方法。技术方案如下：The present invention also provides a method for preparing the multi-layer composite polypropylene material as described above. The technical scheme is as follows:
(1)参见图2，一种如上所述的多层复合聚丙烯材料的制备方法，包括如下步骤：(1) Referring to FIG. 2 , a method for preparing the multilayer composite polypropylene material as described above comprises the following steps:
在约200-260℃条件下熔融包含所述第一改性聚丙烯的原料，在约230-260℃条件下挤出制备第一改性层中间体；Melting the raw material containing the first modified polypropylene at a temperature of about 200-260° C., and extruding at a temperature of about 230-260° C. to prepare a first modified layer intermediate;
在约200-260℃条件下熔融包含所述聚丙烯的原料，在约230-260℃条件下挤出制备芯层中间体；Melting the raw material containing the polypropylene at a temperature of about 200-260° C., and extruding at a temperature of about 230-260° C. to prepare a core layer intermediate;
在约200-260℃条件下熔融包含所述第二改性聚丙烯的原料，在约230-260℃条件下挤出制备第二改性层中间体；Melting the raw material containing the second modified polypropylene at a temperature of about 200-260° C., and extruding at a temperature of about 230-260° C. to prepare a second modified layer intermediate;
在约15-60℃条件下通过制片工艺将所述第一改性层中间体、芯层中间体和第二改性层中间体复合成型制备多层复合聚丙烯材料中间体；The first modified layer intermediate, the core layer intermediate and the second modified layer intermediate are composite-molded by a sheet-making process at about 15-60° C. to prepare a multi-layer composite polypropylene material intermediate;
对所述多层复合聚丙烯材料中间体进行同步拉伸处理制备所述多层复合聚丙烯材料，且纵向总拉伸比约为5-9倍、横向总拉伸比约为4-8倍。The multi-layer composite polypropylene material intermediate is subjected to synchronous stretching treatment to prepare the multi-layer composite polypropylene material, and the total longitudinal stretching ratio is about 5-9 times and the total transverse stretching ratio is about 4-8 times.
在一些实施例中，所述同步拉伸包括如下步骤：In some embodiments, the synchronous stretching comprises the following steps:
逐步升温，分别在约152-157℃、约156-160℃、约159-162℃条件下对所述多层复合聚丙烯材料中间体进行第一拉伸处理、第二拉伸处理和第三拉伸处理，制备多层复合聚丙烯材料中间体I；gradually raising the temperature to perform a first stretching treatment, a second stretching treatment and a third stretching treatment on the multilayer composite polypropylene material intermediate at about 152-157° C., about 156-160° C. and about 159-162° C., respectively, to prepare a multilayer composite polypropylene material intermediate I;
逐步升温，分别在约162-165℃、约162-169℃条件下对所述多层复合聚丙烯材料中间体I进行第一热定型处理和第二热定型处理，制备所述多层复合聚丙烯材料； gradually raising the temperature to perform a first heat setting treatment and a second heat setting treatment on the multilayer composite polypropylene material intermediate I at about 162-165° C. and about 162-169° C., respectively, to prepare the multilayer composite polypropylene material;
本发明的发明人发现，利用第一拉伸处理、第二拉伸处理和第三拉伸处理，可以促进高分子链的有序排列和晶格结构的形成、更好地控制高分子链的取向和排布方式、减少高分子薄膜在拉伸过程中的内应力，从而提高多层复合聚丙烯材料的结晶性能、力学性能及其尺寸的稳定性。此外，当多步拉伸处理与多步热定型处理相结合时，可以有效地释放材料中的内部应力，减少材料的变形和热变形倾向，提高材料的尺寸稳定性；也可以调控高分子材料的微观结构，从而改善其力学性能、减少表面缺陷。The inventors of the present invention have found that the first stretching treatment, the second stretching treatment and the third stretching treatment can promote the orderly arrangement of polymer chains and the formation of lattice structures, better control the orientation and arrangement of polymer chains, and reduce the internal stress of polymer films during the stretching process, thereby improving the crystallization performance, mechanical properties and dimensional stability of multi-layer composite polypropylene materials. In addition, when the multi-step stretching treatment is combined with the multi-step heat setting treatment, the internal stress in the material can be effectively released, the deformation and thermal deformation tendency of the material can be reduced, and the dimensional stability of the material can be improved; the microstructure of the polymer material can also be regulated, thereby improving its mechanical properties and reducing surface defects.
在其中一个实施例中，所述同步拉伸包括两段预热、三段拉伸和两次热定型；In one embodiment, the synchronous stretching includes two stages of preheating, three stages of stretching and two stages of heat setting;
所述两段预热包括第一预热和第二预热，且温度逐步升高，第一预热温度约为130-145℃，第二预热温度约为145-155℃；The two-stage preheating includes a first preheating and a second preheating, and the temperature is gradually increased, the first preheating temperature is about 130-145°C, and the second preheating temperature is about 145-155°C;
所述三段拉伸包括第一拉伸，第二拉伸和第三拉伸，且温度逐步升高，第一拉伸温度约为152-157℃，第二拉伸温度约为156-160℃，第三拉伸温度约为159-162℃；经过三段拉伸后，纵向总拉伸比约为5-9倍(如5、6、7、8、9，在其中一个实施例中，纵向总拉伸比约为6-8倍)、横向总拉伸比约为4-8倍(如4、5、6、7、8，在其中一个实施例中，横向总拉伸比约为5-7倍)；The three-stage stretching includes a first stretching, a second stretching and a third stretching, and the temperature is gradually increased, the first stretching temperature is about 152-157° C., the second stretching temperature is about 156-160° C., and the third stretching temperature is about 159-162° C.; after the three-stage stretching, the total longitudinal stretching ratio is about 5-9 times (such as 5, 6, 7, 8, 9, in one embodiment, the total longitudinal stretching ratio is about 6-8 times), and the total transverse stretching ratio is about 4-8 times (such as 4, 5, 6, 7, 8, in one embodiment, the total transverse stretching ratio is about 5-7 times);
所述两次热定型包括第一热定型和第二热定型，且温度逐步升高，第一热定型温度约为162-165℃，第二热定型温度约为162-169℃。The two heat setting processes include a first heat setting process and a second heat setting process, and the temperature is gradually increased. The first heat setting temperature is about 162-165° C., and the second heat setting temperature is about 162-169° C.
(2)参见图3，另一种如上所述的多层复合聚丙烯材料的制备方法，包括如下步骤：(2) Referring to FIG. 3 , another method for preparing the multilayer composite polypropylene material as described above comprises the following steps:
在约200-260℃条件下熔融包含所述第一改性聚丙烯的原料，在约230-260℃条件下挤出制备第一改性层中间体；Melting the raw material containing the first modified polypropylene at a temperature of about 200-260° C., and extruding at a temperature of about 230-260° C. to prepare a first modified layer intermediate;
在约200-260℃条件下熔融包含所述聚丙烯的原料，在约230-260℃条件下 挤出制备芯层中间体；The raw material containing the polypropylene is melted at about 200-260°C, and the raw material containing the polypropylene is melted at about 230-260°C. Extrusion to prepare a core layer intermediate;
在约200-260℃条件下熔融包含所述第二改性聚丙烯的原料，在约230-260℃条件下挤出制备第二改性层中间体；Melting the raw material containing the second modified polypropylene at a temperature of about 200-260° C., and extruding at a temperature of about 230-260° C. to prepare a second modified layer intermediate;
在约15-60℃条件下通过制片工艺将所述第一改性层中间体、芯层中间体和第二改性层中间体复合成型制备多层复合聚丙烯材料中间体；The first modified layer intermediate, the core layer intermediate and the second modified layer intermediate are composite-molded by a sheet-making process at about 15-60° C. to prepare a multi-layer composite polypropylene material intermediate;
对所述多层复合聚丙烯材料中间体进行异步拉伸处理制备所述多层复合聚丙烯材料，且纵向总拉伸比约为5-9倍、横向总拉伸比约为4-8倍。The multi-layer composite polypropylene material intermediate is subjected to asynchronous stretching treatment to prepare the multi-layer composite polypropylene material, and the total longitudinal stretching ratio is about 5-9 times and the total transverse stretching ratio is about 4-8 times.
在其中一个实施例中，所述异步拉伸包括如下步骤：In one embodiment, the asynchronous stretching comprises the following steps:
在约145-155℃条件下对所述多层复合聚丙烯材料中间体进行纵向拉伸处理，制备多层复合聚丙烯材料中间体II；Performing a longitudinal stretching treatment on the multi-layer composite polypropylene material intermediate at a temperature of about 145-155° C. to prepare a multi-layer composite polypropylene material intermediate II;
在约150-160℃条件下对所述多层复合聚丙烯材料II中间体进行横向拉伸处理，制备多层复合聚丙烯材料中间体III；Performing a transverse stretching treatment on the multilayer composite polypropylene material II intermediate at about 150-160° C. to prepare a multilayer composite polypropylene material intermediate III;
在约165-170℃条件下对所述多层复合聚丙烯材料III进行热成型处理，制备多层复合聚丙烯材料IV；Performing a thermoforming treatment on the multi-layer composite polypropylene material III at a temperature of about 165-170° C. to prepare a multi-layer composite polypropylene material IV;
在约120-135℃条件下对所述多层复合聚丙烯材料IV进行热处理，制备所述多层复合聚丙烯材料。The multi-layer composite polypropylene material IV is heat-treated at about 120-135° C. to prepare the multi-layer composite polypropylene material.
在其中一个实施例中，所述纵向拉伸包括如下步骤：In one embodiment, the longitudinal stretching comprises the following steps:
在约110-135℃条件下预热，在约140-150℃条件下进行拉伸，且纵向总拉伸比约为5-9倍(如5、6、7、8、9，在其中一个实施例中，纵向总拉伸比约为6-8倍)，冷却；Preheating at about 110-135° C., stretching at about 140-150° C., and a total longitudinal stretching ratio of about 5-9 times (such as 5, 6, 7, 8, 9, and in one embodiment, a total longitudinal stretching ratio of about 6-8 times), and cooling;
所述横向拉伸包括如下步骤：The transverse stretching comprises the following steps:
在约120-140℃条件下预热，在约150-160℃条件下进行拉伸，在约165-170℃条件下热成型，且横向总拉伸比约为4-8倍(如4、5、6、7、8，在其中一个实 施例中，横向总拉伸比约为5-7倍)；Preheating at about 120-140°C, stretching at about 150-160°C, thermoforming at about 165-170°C, and the total transverse stretching ratio is about 4-8 times (such as 4, 5, 6, 7, 8, in which one of the actual In the embodiment, the total transverse stretching ratio is about 5-7 times);
所述热处理包括如下步骤：The heat treatment comprises the following steps:
在约120-135℃条件下进行热处理，目的是消除膜内部应力，提高膜的热稳定性。The heat treatment is carried out at about 120-135°C to eliminate the internal stress of the membrane and improve the thermal stability of the membrane.
在其中一个实施例中，所述的多层复合聚丙烯材料的制备方法包括如下步骤：In one embodiment, the method for preparing the multi-layer composite polypropylene material comprises the following steps:
(1)熔融挤出(1) Melt extrusion
将上述第一改性层、芯层、第二改性层采用的原料分别加入到对应的双螺杆挤出机内，在约200-260℃下熔融，然后经过过滤器(10微米滤网)过滤后，通过模头挤出熔体，模头温度约为230-260℃，三层的挤出量控制在约(5％-15％):(70％-90％)：(5％-15％)。The raw materials used for the first modified layer, core layer and second modified layer are respectively added into the corresponding twin-screw extruder, melted at about 200-260°C, and then filtered through a filter (10 micron filter screen), and the melt is extruded through a die head. The die head temperature is about 230-260°C, and the extrusion amount of the three layers is controlled at about (5%-15%): (70%-90%): (5%-15%).
(2)铸片(2) Casting
模头挤出的熔融聚酯料流延到铸片辊上，经铸片辊及水冷的冷却处理成型，冷却温度约为15-60℃。The molten polyester material extruded from the die head is cast onto the casting roll and is formed by the casting roll and water cooling treatment. The cooling temperature is about 15-60°C.
(3)双向拉伸(3) Biaxial stretching
双向拉伸可以通过两种方式实现，即同步拉伸和异步拉伸。Biaxial stretching can be achieved in two ways, namely synchronous stretching and asynchronous stretching.
a.对于同步拉伸，其拉伸工艺如下：a. For synchronous stretching, the stretching process is as follows:
分为预热区、拉伸区、热定型区三个区域，具体地：It is divided into three areas: preheating area, stretching area and heat setting area. Specifically:
预热区：分为两段，温度依次升高，即约130-145℃、约145-155℃；Preheating zone: divided into two sections, the temperature increases successively, i.e. about 130-145℃ and about 145-155℃;
拉伸区：分为三段，温度依次升高，即约152-157℃、约156-160℃、约159-162℃；经过三段拉伸后，拉伸比：纵向总拉伸比约为5-9倍、横向总拉伸比约为4-8倍。Stretching zone: divided into three sections, the temperature increases successively, namely about 152-157°C, about 156-160°C, about 159-162°C; after three-stage stretching, the stretching ratio: the total longitudinal stretching ratio is about 5-9 times, and the total transverse stretching ratio is about 4-8 times.
热定型区：分为两段，温度依次升高，即约162-165℃、约162-169℃。 Heat setting area: divided into two sections, the temperature increases successively, i.e. about 162-165°C and about 162-169°C.
b.对于异步拉伸，其拉伸工艺如下：b. For asynchronous stretching, the stretching process is as follows:
①纵向拉伸：预热温度约为110-135℃；拉伸温度约为140-150℃；纵向总拉伸比约为5-9倍，然后冷却至室温。① Longitudinal stretching: preheating temperature is about 110-135℃; stretching temperature is about 140-150℃; total longitudinal stretching ratio is about 5-9 times, and then cooled to room temperature.
②横向拉伸：预热温度约为120-140℃；拉伸温度约为150-160℃；热定型温度约为165-170℃；横向总拉伸比约为4-8倍。② Transverse stretching: preheating temperature is about 120-140℃; stretching temperature is about 150-160℃; heat setting temperature is about 165-170℃; total transverse stretching ratio is about 4-8 times.
③热处理：热处理温度约为120-135℃，目的是消除膜内部应力，提高膜的热稳定性。③ Heat treatment: The heat treatment temperature is about 120-135℃, the purpose is to eliminate the internal stress of the membrane and improve the thermal stability of the membrane.
(4)收卷：(4) Rolling:
热处理后的膜经平台区空气冷却后，经牵引***进入收卷***进行膜片收卷，收卷张力约20-30N/m。After heat treatment, the film is air-cooled in the platform area and then enters the winding system through the traction system for film winding. The winding tension is about 20-30N/m.
本发明还提供一种复合集流体，其结构包括呈层叠设置的第一保护层，第一金属层，支撑层，第二金属层和第二保护层；The present invention also provides a composite current collector, the structure of which includes a first protective layer, a first metal layer, a support layer, a second metal layer and a second protective layer arranged in layers;
所述支撑层包括根据如上所述的复合聚丙烯材料。The support layer comprises a composite polypropylene material according to above.
本发明提供的复合聚丙烯材料表面张力高且稳定，具有优异的表面粘附性能，与金属结合力强，能与金属牢固地结合在一起。将本发明制备的复合聚丙烯材料作为复合集流体的支撑层(复合集流体的载体)，能与金属层牢固粘结，提升电池性能。The composite polypropylene material provided by the present invention has high and stable surface tension, excellent surface adhesion performance, strong metal bonding, and can be firmly bonded to metal. The composite polypropylene material prepared by the present invention is used as a support layer of a composite current collector (a carrier of a composite current collector), which can firmly bond to a metal layer and improve battery performance.
在其中一个实施例中，所述支撑层的厚度约为1μm-20μm。这样更符合复合集流体的应用要求，同时兼顾制备工艺的难度和成本的高低。In one embodiment, the thickness of the support layer is about 1 μm-20 μm, which better meets the application requirements of the composite current collector while taking into account the difficulty and cost of the preparation process.
两层金属层位于支撑层的两侧，作用为导电。可以理解地，两层金属层的材料可以一致也可以不一致，厚度可以一致也可以不一致。The two metal layers are located on both sides of the support layer and function as a conductor. It is understandable that the materials of the two metal layers may be consistent or inconsistent, and the thicknesses may be consistent or inconsistent.
在一些实施例中，所述第一金属层和第二金属层分别独立包括：电阻率约≤8×10-8Ω·m的金属及其合金。 In some embodiments, the first metal layer and the second metal layer independently include: a metal and an alloy thereof with a resistivity of about ≤8×10-8Ω·m.
在一些实施例中，电阻率约≤8×10-8Ω·m的金属为铜、铝、银、金、锌、钼、钴和镍中的一种或多种，符合要求的合金选自铜合金、铝合金和镍合金中的一种或多种。In some embodiments, the metal with a resistivity of about ≤8×10-8Ω·m is one or more of copper, aluminum, silver, gold, zinc, molybdenum, cobalt and nickel, and the alloy that meets the requirements is selected from one or more of copper alloy, aluminum alloy and nickel alloy.
在一些实施例中，所述第一金属层和第二金属层的厚度分别独立约为500nm-2000nm。In some embodiments, the thickness of the first metal layer and the second metal layer are independently about 500 nm-2000 nm.
在一些实施例中，所述第一金属层和第二金属层的厚度分别独立约约为700nm-1200nm，这样可以具有更好的导电性。In some embodiments, the thickness of the first metal layer and the second metal layer are independently about 700 nm-1200 nm, which can have better conductivity.
在一些实施例中，所述第一金属层和第二金属层分别独立地通过物理气相沉积(如电阻加热真空蒸镀、电子束加热真空蒸镀、激光加热真空蒸镀、磁控溅射等)、电镀、化学镀等方法中的一种或多种制备。In some embodiments, the first metal layer and the second metal layer are independently prepared by one or more methods such as physical vapor deposition (such as resistance heating vacuum evaporation, electron beam heating vacuum evaporation, laser heating vacuum evaporation, magnetron sputtering, etc.), electroplating, and chemical plating.
第一保护层和第二保护层设置在金属层远离支撑层的一侧，作用为防止金属导层被化学腐蚀或物理损坏。可以理解地，两层保护层的材料可以一致也可以不一致，厚度可以一致也可以不一致。The first protective layer and the second protective layer are arranged on the side of the metal layer away from the support layer to prevent the metal conductive layer from being chemically corroded or physically damaged. It can be understood that the materials of the two protective layers can be consistent or inconsistent, and the thickness can be consistent or inconsistent.
在一些实施例中，所述第一保护层和第二保护层分别独立包括：不活泼金属及其合金、金属氧化物和碳材料中的一种或多种。In some embodiments, the first protective layer and the second protective layer independently include: one or more of inactive metals and alloys thereof, metal oxides and carbon materials.
在一些实施例中，不活泼金属选自镍和/或铬。不活泼金属合金选自镍基合金、铬基合金和镍铬铜合金中的一种或多种。金属氧化物选自氧化铜、氧化铝、氧化镍、氧化铬、氧化钴和铜铬氧化物中的一种或多种。碳材料选自石墨、炭黑、乙炔黑、科琴黑、碳纳米量子点、碳纳米管、碳纳米纤维和石墨烯中的一种或多种。In some embodiments, the inactive metal is selected from nickel and/or chromium. The inactive metal alloy is selected from one or more of nickel-based alloys, chromium-based alloys, and nickel-chromium-copper alloys. The metal oxide is selected from one or more of copper oxide, aluminum oxide, nickel oxide, chromium oxide, cobalt oxide, and copper-chromium oxide. The carbon material is selected from one or more of graphite, carbon black, acetylene black, Ketjen black, carbon nano quantum dots, carbon nanotubes, carbon nanofibers, and graphene.
在一些实施例中，所述第一保护层和第二保护层的厚度分别独立约为10nm-150nm。In some embodiments, the thickness of the first protective layer and the second protective layer are independently about 10 nm-150 nm.
在一些实施例中，所述第一保护层和第二保护层的厚度分别独立约为 20nm-100nm，且保护层的厚度不得超过金属层厚度的十分之一。In some embodiments, the thickness of the first protective layer and the second protective layer are respectively about 20nm-100nm, and the thickness of the protective layer shall not exceed one tenth of the thickness of the metal layer.
在一些实施例中，所述第一保护层和第二保护层的制备方法分别独立为物理气相沉积、化学气相沉积、原位成型、涂布等方法中的一种或多种。其中气相沉积法为真空蒸镀或磁控溅射；化学气相沉积为常压化学气相沉积或等离子体增强化学气相沉积；原位成型为在金属层表面原位形成金属氧化物钝化层的方法；涂布法为模头涂布、刮刀涂布或挤压涂布。In some embodiments, the preparation methods of the first protective layer and the second protective layer are independently one or more of physical vapor deposition, chemical vapor deposition, in-situ forming, coating, etc. The vapor deposition method is vacuum evaporation or magnetron sputtering; the chemical vapor deposition is atmospheric pressure chemical vapor deposition or plasma enhanced chemical vapor deposition; the in-situ forming is a method of in-situ forming a metal oxide passivation layer on the surface of the metal layer; the coating method is die coating, blade coating or extrusion coating.
图4是本发明一实施例中的复合集流体的结构示意图，其中，401是第一保护层，402是第一金属层，403是支撑层，404是第二金属层，405是第二保护层。4 is a schematic diagram of the structure of a composite current collector in an embodiment of the present invention, wherein 401 is a first protective layer, 402 is a first metal layer, 403 is a support layer, 404 is a second metal layer, and 405 is a second protective layer.
本发明还提供一种极片，包括如上所述的复合集流体。The present invention also provides a pole piece, comprising the composite current collector as described above.
本发明还提供一种电池，包括如上所述的极片。The present invention also provides a battery, comprising the pole piece as described above.
以下结合具体实施例和对比例进行进一步说明，以下具体实施例中所涉及的原料，若无特殊说明，均可来源于市售，所使用的仪器，若无特殊说明，均可来源于市售。The following is further described in conjunction with specific examples and comparative examples. The raw materials involved in the following specific examples, unless otherwise specified, can all be sourced from commercial sources, and the instruments used, unless otherwise specified, can all be sourced from commercial sources.
实施例1：Embodiment 1:
本实施例提供一种多层复合聚丙烯薄膜及其制备方法，复合集流体及其制备方法。This embodiment provides a multi-layer composite polypropylene film and a preparation method thereof, a composite current collector and a preparation method thereof.
(1)多层复合聚丙烯薄膜：(1) Multilayer composite polypropylene film:
1)原料：1) Raw materials:
a.以质量百分含量计，第一改性层组成如下：
第一聚丙烯            79.8％；
第一改性聚丙烯        20％；
第一抗氧化剂          0.2％； a. In terms of mass percentage, the first modified layer is composed as follows:
First Polypropylene 79.8%;
First modified polypropylene 20%;
First antioxidant 0.2%;
其中，第一聚丙烯的熔融指数为3.0g/10min/(230℃/2.16kg)、分子量分布指数为5.2、等规度为96％，第一改性聚丙烯为顺丁烯二酸酐接枝改性的聚丙烯，其熔融指数为3.2g/10min/(230℃/2.16kg)、分子量分布指数5.5、接枝率为0.2％，第一抗氧化剂为亚磷酸三苯酯。Among them, the melt index of the first polypropylene is 3.0g/10min/(230℃/2.16kg), the molecular weight distribution index is 5.2, and the isotacticity is 96%. The first modified polypropylene is polypropylene grafted with maleic anhydride, and its melt index is 3.2g/10min/(230℃/2.16kg), the molecular weight distribution index is 5.5, and the grafting rate is 0.2%. The first antioxidant is triphenyl phosphite.
b.以质量百分含量计，芯层组成如下：
聚丙烯                 99.8％；
第三抗氧化剂           0.2％；b. In terms of mass percentage, the core layer composition is as follows:
Polypropylene 99.8%;
tertiary antioxidant 0.2%;
其中，聚丙烯的熔融指数为3.0g/10min/(230℃/2.16kg)、分子量分布指数为5.2、等规度为97％，第三抗氧化剂为亚磷酸三苯酯。The melt index of polypropylene is 3.0 g/10 min/(230° C./2.16 kg), the molecular weight distribution index is 5.2, the isotacticity is 97%, and the third antioxidant is triphenyl phosphite.
c.以质量百分含量计，第二改性层组成如下：
第二聚丙烯             79.8％；
第二改性聚丙烯         20％；
第二抗氧化剂           0.2％；c. In terms of mass percentage, the second modified layer is composed as follows:
second polypropylene 79.8%;
Second modified polypropylene 20%;
Second antioxidant 0.2%;
其中，第二聚丙烯的熔融指数为3.0g/10min/(230℃/2.16kg)、分子量分布指数为5.2、等规度为96％，第二改性聚丙烯为顺丁烯二酸酐接枝改性的聚丙烯，其熔融指数为3.2g/10min/(230℃/2.16kg)、分子量分布指数5.5、接枝率为0.2％，第二抗氧化剂为亚磷酸三苯酯。Among them, the melt index of the second polypropylene is 3.0g/10min/(230℃/2.16kg), the molecular weight distribution index is 5.2, and the isotacticity is 96%. The second modified polypropylene is polypropylene grafted with maleic anhydride, and its melt index is 3.2g/10min/(230℃/2.16kg), the molecular weight distribution index is 5.5, and the grafting rate is 0.2%. The second antioxidant is triphenyl phosphite.
2)复合聚丙烯薄膜的制备方法如下：2) The preparation method of the composite polypropylene film is as follows:
①熔融挤出：① Melt extrusion:
将上述第一改性层、芯层、第二改性层层的原料分别加入到对应的双螺杆挤出机内，在250℃下熔融，然后经过过滤器(10微米滤网)过滤后，通过模头挤出熔体，模头温度为260℃，三层的挤出量比例控制在10％:80％:10％。The raw materials of the first modified layer, the core layer and the second modified layer are respectively added into the corresponding twin-screw extruder, melted at 250°C, filtered through a filter (10 micron filter screen), and then extruded through a die head with a die head temperature of 260°C. The extrusion ratio of the three layers is controlled at 10%:80%:10%.
②铸片： ② Casting sheet:
将模头挤出的熔融聚酯料流延到铸片辊上，经铸片辊及水冷的冷却处理成型，冷却温度为30℃。The molten polyester material extruded from the die head is cast onto the casting roll, and is formed by the casting roll and water cooling treatment, and the cooling temperature is 30°C.
③双向拉伸③Two-way stretch
采用同步拉伸的工艺，其拉伸工艺如下：分为预热区、拉伸区、热定型区三个区域，具体地：The synchronous stretching process is as follows: it is divided into three areas: preheating area, stretching area, and heat setting area. Specifically:
预热区：分为两段，温度依次升高，即135℃、150℃；Preheating zone: divided into two sections, the temperature increases successively, i.e. 135℃ and 150℃;
拉伸区：分为三段，温度依次升高，即153℃、157℃、160℃；拉伸比：纵向总拉伸比为6倍、横向总拉伸比为5倍；Stretching zone: divided into three sections, the temperature increases successively, namely 153℃, 157℃, 160℃; stretching ratio: the total longitudinal stretching ratio is 6 times, and the total transverse stretching ratio is 5 times;
热定型区：分为两段，温度依次升高，即163℃、166℃。Heat setting area: divided into two sections, the temperature increases successively, namely 163℃ and 166℃.
④热处理后的膜经平台区空气冷却后，经牵引***进入收卷***进行膜片收卷，收卷张力为30N/m。制备出总厚度为4.5微米的多层复合聚丙烯膜，第一改性层和第二改性层的厚度均为0.45微米，芯层的厚度为3.6微米。④ After the heat-treated film is air-cooled in the platform area, it enters the winding system through the traction system for film winding, and the winding tension is 30N/m. A multi-layer composite polypropylene film with a total thickness of 4.5 microns is prepared, the thickness of the first modified layer and the second modified layer are both 0.45 microns, and the thickness of the core layer is 3.6 microns.
(2)复合集流体制备：(2) Preparation of composite current collector:
①金属导电层的制备：将上述制备的、表面进行清洁处理的多层复合聚丙烯膜置于真空蒸镀的舱体内，以1300-2000℃的高温将金属蒸发室内的高纯铝丝(纯度大于99.99％)熔化蒸发，蒸发后的金属原子经过真空镀膜室内的冷却***，沉积在高分子基膜的两个表面，形成厚度为1微米的铝金属导电层。① Preparation of metal conductive layer: The multi-layer composite polypropylene film prepared as above and cleaned on the surface is placed in a vacuum evaporation chamber, and the high-purity aluminum wire (purity greater than 99.99%) in the metal evaporation chamber is melted and evaporated at a high temperature of 1300-2000°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and are deposited on the two surfaces of the polymer base film to form an aluminum metal conductive layer with a thickness of 1 micron.
②保护层的制备：通过超声分散的方法将1g碳纳米管均匀分散到999g氮甲基吡咯烷酮(NMP)溶液中，配制成固含量为0.1wt.％的涂布液，然后通过模头涂布的工艺将涂布液均匀涂覆到金属导电层的表面，其中涂覆量控制在80微米，最后在100℃下进行干燥。② Preparation of protective layer: 1g of carbon nanotubes is uniformly dispersed in 999g of nitrogen methyl pyrrolidone (NMP) solution by ultrasonic dispersion to prepare a coating solution with a solid content of 0.1wt.%, and then the coating solution is uniformly coated on the surface of the metal conductive layer by a die coating process, wherein the coating amount is controlled at 80 microns, and finally dried at 100°C.
实施例2： Embodiment 2:
与实施例1基本相同，区别在于：改变改性层中各原料的含量，具体地：The method is basically the same as Example 1, except that the content of each raw material in the modified layer is changed, specifically:
第一改性层中聚丙烯、顺丁烯二酸酐接枝改性的聚丙烯、亚磷酸三苯酯的含量分别为49.8％、50.0％、0.2％；The contents of polypropylene, maleic anhydride grafted modified polypropylene, and triphenyl phosphite in the first modified layer are 49.8%, 50.0%, and 0.2%, respectively;
第二改性层中聚丙烯、顺丁烯二酸酐接枝改性的聚丙烯、亚磷酸三苯酯的含量分别为49.8％、50.0％、0.2％。The contents of polypropylene, polypropylene grafted with maleic anhydride and triphenyl phosphite in the second modified layer are 49.8%, 50.0% and 0.2% respectively.
实施例3：Embodiment 3:
与实施例1基本相同，区别在于：改变改性层中各原料的含量，具体地：The method is basically the same as Example 1, except that the content of each raw material in the modified layer is changed, specifically:
第一改性层中聚丙烯、顺丁烯二酸酐接枝改性的聚丙烯、亚磷酸三苯酯的含量分别为0％、99.8％、0.2％；The contents of polypropylene, maleic anhydride grafted modified polypropylene, and triphenyl phosphite in the first modified layer are 0%, 99.8%, and 0.2%, respectively;
第二改性层中聚丙烯、顺丁烯二酸酐接枝改性的聚丙烯、亚磷酸三苯酯的含量分别为0％、99.8％、0.2％。The contents of polypropylene, polypropylene grafted with maleic anhydride, and triphenyl phosphite in the second modified layer are 0%, 99.8%, and 0.2%, respectively.
实施例4：Embodiment 4:
与实施例1基本相同，区别在于：改变改性层中各原料的含量，具体地：The method is basically the same as Example 1, except that the content of each raw material in the modified layer is changed, specifically:
第一改性层中聚丙烯、顺丁烯二酸酐接枝改性的聚丙烯、亚磷酸三苯酯的含量分别为79.5％、20.0％、0.5％；The contents of polypropylene, polypropylene grafted with maleic anhydride, and triphenyl phosphite in the first modified layer are 79.5%, 20.0%, and 0.5%, respectively;
第二改性层中聚丙烯、顺丁烯二酸酐接枝改性的聚丙烯、亚磷酸三苯酯的含量分别为79.5％、20.0％、0.5％。The contents of polypropylene, polypropylene grafted with maleic anhydride and triphenyl phosphite in the second modified layer are 79.5%, 20.0% and 0.5% respectively.
实施例5：Embodiment 5:
与实施例1基本相同，区别在于：改变改性层中各原料的含量，具体地：The method is basically the same as Example 1, except that the content of each raw material in the modified layer is changed, specifically:
第一改性层中聚丙烯、顺丁烯二酸酐接枝改性的聚丙烯、亚磷酸三苯酯的 含量分别为80.8％、19.0％、0.2％；The first modified layer contains polypropylene, maleic anhydride grafted modified polypropylene, and triphenyl phosphite. The contents are 80.8%, 19.0%, and 0.2% respectively;
第二改性层中聚丙烯、顺丁烯二酸酐接枝改性的聚丙烯、亚磷酸三苯酯的含量分别为80.8％、19.0％、0.2％。The contents of polypropylene, polypropylene grafted with maleic anhydride, and triphenyl phosphite in the second modified layer are 80.8%, 19.0%, and 0.2%, respectively.
实施例6：Embodiment 6:
与实施例1基本相同，区别在于：改变改性层中各原料的含量，具体地：The method is basically the same as Example 1, except that the content of each raw material in the modified layer is changed, specifically:
第一改性层中聚丙烯、顺丁烯二酸酐接枝改性的聚丙烯、亚磷酸三苯酯的含量分别为0％、99.9％、0.1％；The contents of polypropylene, maleic anhydride grafted modified polypropylene, and triphenyl phosphite in the first modified layer are 0%, 99.9%, and 0.1%, respectively;
第二改性层中聚丙烯、顺丁烯二酸酐接枝改性的聚丙烯、亚磷酸三苯酯的含量分别为0％、99.9％、0.1％。The contents of polypropylene, polypropylene grafted with maleic anhydride and triphenyl phosphite in the second modified layer are 0%, 99.9% and 0.1% respectively.
实施例7：Embodiment 7:
与实施例2基本相同，区别在于：改变改性层中改性聚丙烯的接枝率，具体地：The method is basically the same as Example 2, except that the grafting rate of the modified polypropylene in the modified layer is changed, specifically:
第一改性层中顺丁烯二酸酐接枝改性的聚丙烯接枝率为0.9％；The grafting rate of polypropylene modified by maleic anhydride grafting in the first modified layer is 0.9%;
第二改性层中顺丁烯二酸酐接枝改性的聚丙烯接枝率为0.9％。The grafting rate of the polypropylene modified by grafting with maleic anhydride in the second modified layer was 0.9%.
实施例8：Embodiment 8:
与实施例2基本相同，区别在于：改变改性层中改性聚丙烯的接枝率，具体地：The method is basically the same as Example 2, except that the grafting rate of the modified polypropylene in the modified layer is changed, specifically:
第一改性层中顺丁烯二酸酐接枝改性的聚丙烯接枝率为1.5％；The grafting rate of polypropylene modified by maleic anhydride grafting in the first modified layer is 1.5%;
第二改性层中顺丁烯二酸酐接枝改性的聚丙烯接枝率为1.5％。 The grafting rate of the polypropylene modified by grafting with maleic anhydride in the second modified layer was 1.5%.
实施例9：Embodiment 9:
与实施例2基本相同，区别在于：改变改性层中改性聚丙烯的接枝率，具体地：The method is basically the same as Example 2, except that the grafting rate of the modified polypropylene in the modified layer is changed, specifically:
第一改性层中顺丁烯二酸酐接枝改性的聚丙烯接枝率为0.1％；The grafting rate of polypropylene modified by maleic anhydride grafting in the first modified layer is 0.1%;
第二改性层中顺丁烯二酸酐接枝改性的聚丙烯接枝率为0.1％。The grafting rate of the polypropylene modified by grafting with maleic anhydride in the second modified layer was 0.1%.
实施例10：Embodiment 10:
与实施例2基本相同，区别在于：改变改性层中改性聚丙烯的接枝率，具体地：The method is basically the same as Example 2, except that the grafting rate of the modified polypropylene in the modified layer is changed, specifically:
第一改性层中顺丁烯二酸酐接枝改性的聚丙烯接枝率为1.6％；The grafting rate of maleic anhydride grafted polypropylene in the first modified layer is 1.6%;
第二改性层中顺丁烯二酸酐接枝改性的聚丙烯接枝率为1.6％。The grafting rate of the polypropylene modified by grafting with maleic anhydride in the second modified layer was 1.6%.
实施例11：Embodiment 11:
与实施例7基本相同，区别在于：改变改性层中改性聚丙烯的熔融指数，具体地：The method is substantially the same as Example 7, except that the melt index of the modified polypropylene in the modified layer is changed, specifically:
第一改性层中顺丁烯二酸酐接枝改性的熔融指数为3.6g/10min/(230℃/2.16kg)；The melt index of the maleic anhydride grafted modified layer in the first modified layer is 3.6 g/10 min/(230°C/2.16 kg);
第二改性层中顺丁烯二酸酐接枝改性的熔融指数为3.6g/10min/(230℃/2.16kg)。The melt index of the maleic anhydride grafted modified layer in the second modified layer was 3.6 g/10 min/(230° C./2.16 kg).
实施例12：Embodiment 12:
与实施例7基本相同，区别在于：改变改性层中改性聚丙烯的熔融指数，具体地： The method is substantially the same as Example 7, except that the melt index of the modified polypropylene in the modified layer is changed, specifically:
第一改性层中顺丁烯二酸酐接枝改性的熔融指数为4.0g/10min/(230℃/2.16kg)；The melt index of the maleic anhydride grafted modified layer in the first modified layer is 4.0 g/10 min/(230°C/2.16 kg);
第二改性层中顺丁烯二酸酐接枝改性的熔融指数为4.0g/10min/(230℃/2.16kg)。The melt index of the maleic anhydride grafted modified layer in the second modified layer was 4.0 g/10 min/(230° C./2.16 kg).
实施例13：Embodiment 13:
与实施例7基本相同，区别在于：改变改性层中改性聚丙烯的熔融指数，具体地：The method is substantially the same as Example 7, except that the melt index of the modified polypropylene in the modified layer is changed, specifically:
第一改性层中顺丁烯二酸酐接枝改性的熔融指数为3.1g/10min/(230℃/2.16kg)；The melt index of the maleic anhydride grafted modified layer in the first modified layer is 3.1 g/10 min/(230°C/2.16 kg);
第二改性层中顺丁烯二酸酐接枝改性的熔融指数为3.1g/10min/(230℃/2.16kg)。The melt index of the maleic anhydride grafted modified layer in the second modified layer was 3.1 g/10 min/(230° C./2.16 kg).
实施例14：Embodiment 14:
与实施例7基本相同，区别在于：改变改性层中改性聚丙烯的熔融指数，具体地：The method is substantially the same as Example 7, except that the melt index of the modified polypropylene in the modified layer is changed, specifically:
第一改性层中顺丁烯二酸酐接枝改性的熔融指数为4.1g/10min/(230℃/2.16kg)；The melt index of the maleic anhydride grafted modified layer in the first modified layer is 4.1 g/10 min/(230°C/2.16 kg);
第二改性层中顺丁烯二酸酐接枝改性的熔融指数为4.1g/10min/(230℃/2.16kg)。The melt index of the maleic anhydride grafted modified layer in the second modified layer was 4.1 g/10 min/(230° C./2.16 kg).
实施例15：Embodiment 15:
与实施例11基本相同，区别在于：改变改性层改性聚丙烯的分子量分布指 数，具体地：The same as Example 11, except that the molecular weight distribution index of the modified polypropylene in the modified layer is changed. Number, specifically:
第一改性层中顺丁烯二酸酐接枝改性的分子量分布指数为5.0；The molecular weight distribution index of the maleic anhydride graft modification in the first modified layer is 5.0;
第二改性层中顺丁烯二酸酐接枝改性的分子量分布指数为5.0。The molecular weight distribution index of the maleic anhydride graft modification in the second modified layer was 5.0.
实施例16：Embodiment 16:
与实施例11基本相同，区别在于：改变改性层改性聚丙烯的分子量分布指数，具体地：The method is basically the same as Example 11, except that the molecular weight distribution index of the modified polypropylene in the modified layer is changed, specifically:
第一改性层中顺丁烯二酸酐接枝改性的分子量分布指数为4.6；The molecular weight distribution index of maleic anhydride graft modification in the first modified layer is 4.6;
第二改性层中顺丁烯二酸酐接枝改性的分子量分布指数为4.6。The molecular weight distribution index of the maleic anhydride graft modification in the second modified layer was 4.6.
实施例17：Embodiment 17:
与实施例11基本相同，区别在于：改变改性层改性聚丙烯的分子量分布指数，具体地：The method is basically the same as Example 11, except that the molecular weight distribution index of the modified polypropylene in the modified layer is changed, specifically:
第一改性层中顺丁烯二酸酐接枝改性的分子量分布指数为5.6；The molecular weight distribution index of maleic anhydride graft modification in the first modified layer is 5.6;
第二改性层中顺丁烯二酸酐接枝改性的分子量分布指数为5.6。The molecular weight distribution index of the maleic anhydride graft modification in the second modified layer was 5.6.
实施例18：Embodiment 18:
与实施例15基本相同，区别在于：改变改性层改性聚丙烯的分子量分布指数，具体地：The method is basically the same as Example 15, except that the molecular weight distribution index of the modified polypropylene in the modified layer is changed, specifically:
第一改性层中顺丁烯二酸酐接枝改性的分子量分布指数为4.5；The molecular weight distribution index of the maleic anhydride grafted modification in the first modified layer is 4.5;
第二改性层中顺丁烯二酸酐接枝改性的分子量分布指数为4.5。The molecular weight distribution index of the maleic anhydride graft modification in the second modified layer was 4.5.
实施例19： Embodiment 19:
与实施例15基本相同，区别在于：改变了同步拉伸中的纵向拉伸比，三段拉伸处理后总纵向拉伸比为7:1。It is basically the same as Example 15, except that the longitudinal stretching ratio in the synchronous stretching is changed, and the total longitudinal stretching ratio after three-stage stretching treatment is 7:1.
实施例20：Embodiment 20:
与实施例15基本相同，区别在于：改变了同步拉伸中的纵向拉伸比，三段拉伸处理后总纵向拉伸比为8:1。It is basically the same as Example 15, except that the longitudinal stretching ratio in the synchronous stretching is changed, and the total longitudinal stretching ratio after three-stage stretching treatment is 8:1.
实施例21：Embodiment 21:
与实施例15基本相同，区别在于：改变了同步拉伸中的纵向拉伸比，三段拉伸处理后总纵向拉伸比为5:1。It is basically the same as Example 15, except that the longitudinal stretching ratio in the synchronous stretching is changed, and the total longitudinal stretching ratio after three-stage stretching treatment is 5:1.
实施例22：Embodiment 22:
与实施例15基本相同，区别在于：改变了同步拉伸中的纵向拉伸比，三段拉伸处理后总纵向拉伸比为9:1。It is basically the same as Example 15, except that the longitudinal stretching ratio in the synchronous stretching is changed, and the total longitudinal stretching ratio after three-stage stretching treatment is 9:1.
实施例23：Embodiment 23:
与实施例1基本相同，区别在于：改变芯层各原料的含量，具体地：The method is basically the same as Example 1, except that the content of each raw material of the core layer is changed, specifically:
聚丙烯、亚磷酸三苯酯的含量分别为99.5％、0.5％。The contents of polypropylene and triphenyl phosphite are 99.5% and 0.5% respectively.
实施例24：Embodiment 24:
与实施例19基本相同，区别在于：将第一改性层和第二改性层中的顺丁烯二酸酐接枝改性的聚丙烯均换成丙烯酸缩水甘油酯接枝改性的聚丙烯。 It is basically the same as Example 19, except that the polypropylene modified by grafting maleic anhydride in the first modified layer and the second modified layer is replaced by polypropylene modified by grafting glycidyl acrylate.
实施例25：Embodiment 25:
与实施例19基本相同，区别在于：改变了改性聚丙烯的种类，具体地：将第一改性层和第二改性中的顺丁烯二酸酐接枝改性的聚丙烯均换成二乙烯三胺-甲基丙烯酸缩水甘油酯接枝改性的聚丙烯。It is basically the same as Example 19, except that the type of modified polypropylene is changed, specifically, the polypropylene grafted modified with maleic anhydride in the first modified layer and the second modified layer is replaced with polypropylene grafted modified with diethylenetriamine-glycidyl methacrylate.
实施例26：Embodiment 26:
与实施例1基本相同，区别在于：改变了第一改性层和第二改性层中聚丙烯的等规度，具体地：第一改性层和第二改性层中聚丙烯的等规度均为93％。It is basically the same as Example 1, except that: the isotacticity of the polypropylene in the first modified layer and the second modified layer is changed, specifically: the isotacticity of the polypropylene in the first modified layer and the second modified layer is 93%.
实施例27：Embodiment 27:
与实施例1基本相同，区别在于：改变了第一改性层和第二改性层中聚丙烯的等规度，具体地：第一改性层和第二改性层中聚丙烯的等规度均为90％。It is basically the same as Example 1, except that: the isotacticity of the polypropylene in the first modified layer and the second modified layer is changed, specifically: the isotacticity of the polypropylene in the first modified layer and the second modified layer is 90%.
实施例28：Embodiment 28:
与实施例1基本相同，区别在于：改变了第一改性层和第二改性层中聚丙烯的等规度，具体地：第一改性层和第二改性层中聚丙烯的等规度均为89％。It is basically the same as Example 1, except that: the isotacticity of the polypropylene in the first modified layer and the second modified layer is changed, specifically: the isotacticity of the polypropylene in the first modified layer and the second modified layer is 89%.
实施例29：Embodiment 29:
与实施例1基本相同，区别在于：改变了第一改性层和第二改性层中聚丙烯的等规度，具体地：第一改性层和第二改性层中聚丙烯的等规度均为97％。It is basically the same as Example 1, except that: the isotacticity of the polypropylene in the first modified layer and the second modified layer is changed, specifically: the isotacticity of the polypropylene in the first modified layer and the second modified layer is 97%.
实施例30：Embodiment 30:
与实施例1基本相同，区别在于：芯层中采用的聚丙烯的等规度为99％。 It is basically the same as Example 1, except that the isotacticity of the polypropylene used in the core layer is 99%.
实施例31：Embodiment 31:
与实施例1基本相同，区别在于：芯层中采用的聚丙烯的等规度为96％。It is basically the same as Example 1, except that the isotacticity of the polypropylene used in the core layer is 96%.
实施例32：Embodiment 32:
与实施例1基本相同，区别在于：第一改性层、芯层和第二改性层中采用的抗氧化剂亚磷酸三苯酯的浓度为0.1％。It is basically the same as Example 1, except that the concentration of the antioxidant triphenyl phosphite used in the first modified layer, the core layer and the second modified layer is 0.1%.
第一改性层中聚丙烯、顺丁烯二酸酐接枝改性的聚丙烯、亚磷酸三苯酯的含量分别为79.9％、20％、0.1％；The contents of polypropylene, maleic anhydride grafted polypropylene, and triphenyl phosphite in the first modified layer are 79.9%, 20%, and 0.1%, respectively;
芯层中聚丙烯、亚磷酸三苯酯的含量分别为99.9％、0.1％；The contents of polypropylene and triphenyl phosphite in the core layer are 99.9% and 0.1% respectively;
第二改性层中聚丙烯、顺丁烯二酸酐接枝改性的聚丙烯、亚磷酸三苯酯的含量分别为79.9％、20％、0.1％。The contents of polypropylene, polypropylene grafted with maleic anhydride and triphenyl phosphite in the second modified layer are 79.9%, 20% and 0.1% respectively.
实施例33：Embodiment 33:
与实施例1基本相同，区别在于：第一改性层、芯层和第二改性层中采用的抗氧化剂亚磷酸三苯酯的浓度为0.6％。It is basically the same as Example 1, except that the concentration of the antioxidant triphenyl phosphite used in the first modified layer, the core layer and the second modified layer is 0.6%.
第一改性层中聚丙烯、顺丁烯二酸酐接枝改性的聚丙烯、亚磷酸三苯酯的含量分别为79.4％、20％、0.6％；The contents of polypropylene, maleic anhydride grafted polypropylene, and triphenyl phosphite in the first modified layer are 79.4%, 20%, and 0.6%, respectively;
芯层中聚丙烯、亚磷酸三苯酯的含量分别为99.4％、0.6％；The contents of polypropylene and triphenyl phosphite in the core layer are 99.4% and 0.6% respectively;
第二改性层中聚丙烯、顺丁烯二酸酐接枝改性的聚丙烯、亚磷酸三苯酯的含量分别为79.4％、20％、0.6％。The contents of polypropylene, polypropylene grafted with maleic anhydride and triphenyl phosphite in the second modified layer are 79.4%, 20% and 0.6% respectively.
实施例34： Embodiment 34:
与实施例1基本相同，区别在于：改变第二改性层中顺丁烯二酸酐接枝改性的聚丙烯的含量，具体地：The method is basically the same as Example 1, except that the content of the polypropylene grafted with maleic anhydride in the second modified layer is changed, specifically:
(1)多层复合聚丙烯薄膜：(1) Multilayer composite polypropylene film:
1)原料：1) Raw materials:
a.以质量百分含量计，第一改性层组成如下：
第一聚丙烯             79.8％；
第一改性聚丙烯         20％；
第一抗氧化剂           0.2％；a. In terms of mass percentage, the first modified layer is composed as follows:
First Polypropylene 79.8%;
First modified polypropylene 20%;
First antioxidant 0.2%;
其中，第一聚丙烯的熔融指数为3.0g/10min/(230℃/2.16kg)、分子量分布指数为5.2、等规度为96％，第一改性聚丙烯为顺丁烯二酸酐接枝改性的聚丙烯，其熔融指数为3.2g/10min/(230℃/2.16kg)、分子量分布指数5.5、接枝率为0.2％，第一抗氧化剂为亚磷酸三苯酯。Among them, the melt index of the first polypropylene is 3.0g/10min/(230℃/2.16kg), the molecular weight distribution index is 5.2, and the isotacticity is 96%. The first modified polypropylene is polypropylene grafted with maleic anhydride, and its melt index is 3.2g/10min/(230℃/2.16kg), the molecular weight distribution index is 5.5, and the grafting rate is 0.2%. The first antioxidant is triphenyl phosphite.
b.以质量百分含量计，芯层组成如下：
聚丙烯                 99.8％；
第三抗氧化剂           0.2％；b. In terms of mass percentage, the core layer composition is as follows:
Polypropylene 99.8%;
tertiary antioxidant 0.2%;
其中，聚丙烯的熔融指数为3.0g/10min/(230℃/2.16kg)、分子量分布指数为5.2、等规度为97％，第三抗氧化剂为亚磷酸三苯酯。The melt index of polypropylene is 3.0 g/10 min/(230° C./2.16 kg), the molecular weight distribution index is 5.2, the isotacticity is 97%, and the third antioxidant is triphenyl phosphite.
c.以质量百分含量计，第二改性层组成如下：
第二聚丙烯             69.8％；
第二改性聚丙烯         30％；
第二抗氧化剂           0.2％；c. In terms of mass percentage, the second modified layer is composed as follows:
second polypropylene 69.8%;
Second modified polypropylene 30%;
Second antioxidant 0.2%;
其中，第二聚丙烯的熔融指数为3.0g/10min/(230℃/2.16kg)、分子量分布指数为5.2、等规度为96％，第二改性聚丙烯为顺丁烯二酸酐接枝改性的聚丙烯， 其熔融指数为3.2g/10min/(230℃/2.16kg)、分子量分布指数5.5、接枝率为0.2％，第二抗氧化剂为亚磷酸三苯酯。The second polypropylene has a melt index of 3.0 g/10 min/(230° C./2.16 kg), a molecular weight distribution index of 5.2, and an isotacticity of 96%. The second modified polypropylene is a polypropylene grafted with maleic anhydride. Its melt index is 3.2 g/10 min/(230° C./2.16 kg), its molecular weight distribution index is 5.5, its grafting rate is 0.2%, and its second antioxidant is triphenyl phosphite.
实施例35：Embodiment 35:
与实施例1基本相同，区别在于：改变第二改性层中改性聚丙烯的种类，具体地：The method is basically the same as Example 1, except that the type of modified polypropylene in the second modified layer is changed, specifically:
(1)多层复合聚丙烯薄膜：(1) Multilayer composite polypropylene film:
1)原料：1) Raw materials:
a.以质量百分含量计，第一改性层组成如下：
第一聚丙烯             79.8％；
第一改性聚丙烯         20％；
第一抗氧化剂           0.2％；a. In terms of mass percentage, the first modified layer is composed as follows:
First Polypropylene 79.8%;
First modified polypropylene 20%;
First antioxidant 0.2%;
其中，第一聚丙烯的熔融指数为3.0g/10min/(230℃/2.16kg)、分子量分布指数为5.2、等规度为96％，第一改性聚丙烯为顺丁烯二酸酐接枝改性的聚丙烯，其熔融指数为3.2g/10min/(230℃/2.16kg)、分子量分布指数5.5、接枝率为0.2％，第一抗氧化剂为亚磷酸三苯酯。Among them, the melt index of the first polypropylene is 3.0g/10min/(230℃/2.16kg), the molecular weight distribution index is 5.2, and the isotacticity is 96%. The first modified polypropylene is polypropylene grafted with maleic anhydride, and its melt index is 3.2g/10min/(230℃/2.16kg), the molecular weight distribution index is 5.5, and the grafting rate is 0.2%. The first antioxidant is triphenyl phosphite.
b.以质量百分含量计，芯层组成如下：
聚丙烯                 99.8％；
第三抗氧化剂           0.2％；b. In terms of mass percentage, the core layer composition is as follows:
Polypropylene 99.8%;
tertiary antioxidant 0.2%;
其中，聚丙烯的熔融指数为3.0g/10min/(230℃/2.16kg)、分子量分布指数为5.2、等规度为97％，第三抗氧化剂为亚磷酸三苯酯。The melt index of polypropylene is 3.0 g/10 min/(230° C./2.16 kg), the molecular weight distribution index is 5.2, the isotacticity is 97%, and the third antioxidant is triphenyl phosphite.
c.以质量百分含量计，第二改性层组成如下：
第二聚丙烯             79.8％；
第二改性聚丙烯        20％；
第二抗氧化剂          0.2％；c. In terms of mass percentage, the second modified layer is composed as follows:
second polypropylene 79.8%;
Second modified polypropylene 20%;
Second antioxidant 0.2%;
其中，第二聚丙烯的熔融指数为3.0g/10min/(230℃/2.16kg)、分子量分布指数为5.2、等规度为96％，第二改性聚丙烯为二乙烯三胺-甲基丙烯酸缩水甘油酯接枝改性的聚丙烯，其熔融指数为3.2g/10min/(230℃/2.16kg)、分子量分布指数5.5、接枝率为0.2％，第二抗氧化剂为亚磷酸三苯酯。Among them, the melt index of the second polypropylene is 3.0g/10min/(230℃/2.16kg), the molecular weight distribution index is 5.2, and the isotacticity is 96%. The second modified polypropylene is diethylenetriamine-methacrylate grafted modified polypropylene, and its melt index is 3.2g/10min/(230℃/2.16kg), the molecular weight distribution index is 5.5, and the grafting rate is 0.2%. The second antioxidant is triphenyl phosphite.
实施例36：Embodiment 36:
与实施例19基本相同，区别在于：第一及第二改性层中的改性聚丙烯为顺丁烯二酸酐低聚物(聚合度为10)接枝改性的聚丙烯。It is basically the same as Example 19, except that the modified polypropylene in the first and second modified layers is polypropylene graft-modified with maleic anhydride oligomer (degree of polymerization is 10).
实施例37：Embodiment 37:
与实施例19基本相同，区别在于：第一及第二改性层中的改性聚丙烯为琥珀酰荧光素-琥珀酸酐接枝的聚丙烯接枝改性的聚丙烯。It is basically the same as Example 19, except that the modified polypropylene in the first and second modified layers is polypropylene grafted with succinylfluorescein-succinic anhydride.
实施例38：Embodiment 38:
与实施例19基本相同，区别在于：第一及第二改性层中的改性聚丙烯为顺丁烯二酸酐低聚物(聚合度为10)接枝改性的聚丙烯与琥珀酰荧光素-琥珀酸酐接枝的聚丙烯混合物，且二者质量比为1:1。It is basically the same as Example 19, except that the modified polypropylene in the first and second modified layers is a mixture of polypropylene grafted with maleic anhydride oligomer (degree of polymerization is 10) and polypropylene grafted with succinylfluorescein-succinic anhydride, and the mass ratio of the two is 1:1.
对比例1：Comparative Example 1:
与实施例1基本相同，区别在于：第一改性层和第二改性层中均不添加顺丁烯二酸酐接枝改性的聚丙烯。The method is basically the same as Example 1, except that no polypropylene modified by grafting maleic anhydride is added to the first modified layer and the second modified layer.
对比例2：Comparative Example 2:
与实施例1基本相同，区别在于：第一改性层不添加顺丁烯二酸酐接枝改 性的聚丙烯。The same as Example 1, except that the first modified layer does not contain maleic anhydride grafted modified Polypropylene.
对比例3：Comparative Example 3:
与实施例1基本相同，区别在于：三层均为改性层：即第一改性层、第二改性层及芯层中聚丙烯、顺丁烯二酸酐接枝改性的聚丙烯、亚磷酸三苯酯的含量分别为79.8％、20％、0.2％。It is basically the same as Example 1, except that: all three layers are modified layers: that is, the contents of polypropylene, maleic anhydride grafted modified polypropylene, and triphenyl phosphite in the first modified layer, the second modified layer, and the core layer are 79.8%, 20%, and 0.2%, respectively.
对比例4：Comparative Example 4:
与对比例1基本相同，区别在于：复合聚丙烯薄膜制备完成后，进行单面电晕处理，电晕处理强度为16W·min/m2。It is basically the same as Comparative Example 1, except that after the composite polypropylene film is prepared, a single-sided corona treatment is performed, and the corona treatment intensity is 16 W·min/m2.
对比例5：Comparative Example 5:
与实施例1基本相同，区别在于：同步拉伸设置为1段，一步拉伸到位，温度为160℃；拉伸比：纵向总拉伸比为6倍、横向总拉伸比为5倍；The method is basically the same as Example 1, except that: the synchronous stretching is set to 1 stage, the stretching is in place in one step, the temperature is 160°C; the stretching ratio: the total longitudinal stretching ratio is 6 times, and the total transverse stretching ratio is 5 times;
对比例6：Comparative Example 6:
与实施例2基本相同，区别在于：改变改性层中改性聚丙烯的接枝率，具体地：The method is basically the same as Example 2, except that the grafting rate of the modified polypropylene in the modified layer is changed, specifically:
第一改性层中顺丁烯二酸酐接枝改性的聚丙烯接枝率为2.2％；The grafting rate of polypropylene modified by maleic anhydride grafting in the first modified layer is 2.2%;
第二改性层中顺丁烯二酸酐接枝改性的聚丙烯接枝率为2.2％。The grafting rate of the polypropylene modified by grafting with maleic anhydride in the second modified layer was 2.2%.
测试评价：Test evaluation:
1、如前所述制备多层复合聚丙烯薄膜的目的在于提升膜的表面粘附性能及 力学性能，进而提升以此聚丙烯薄膜为基材制备的复合集流体的性能，这里对影响聚丙烯膜表面粘附性能的因素即表面张力及表层自由体积、复合集流体中多层复合聚丙烯膜与表层金属层的粘结力等指标进行了测试及表征，此外，还对制备的多层复合聚丙烯膜的拉伸强度及由于表层缺陷引起的不良率进行了测试，具体测试方法如下：1. As mentioned above, the purpose of preparing the multilayer composite polypropylene film is to improve the surface adhesion performance of the film and Mechanical properties, thereby improving the performance of the composite current collector prepared with this polypropylene film as the substrate. Here, the factors affecting the surface adhesion performance of the polypropylene film, namely the surface tension and surface free volume, the adhesion between the multi-layer composite polypropylene film and the surface metal layer in the composite current collector, and other indicators are tested and characterized. In addition, the tensile strength of the prepared multi-layer composite polypropylene film and the defective rate caused by surface defects are also tested. The specific test methods are as follows:
①表面张力：按照GB/T 14216-2008对上述制备的多层复合聚丙烯膜的初始及存储三个月后的表面张力进行测试。① Surface tension: The surface tension of the multi-layer composite polypropylene film prepared above was tested at the beginning and after three months of storage in accordance with GB/T 14216-2008.
②聚丙烯膜表层自由体积：将表面改性聚丙烯层从制备的多层复合聚丙烯膜中剥离下来，然后利用正电子湮灭寿命谱(PALS)对常温下的表层的自由体积进行表征。② Free volume of the polypropylene film surface: The surface modified polypropylene layer was peeled off from the prepared multilayer composite polypropylene film, and then the free volume of the surface layer at room temperature was characterized by positron annihilation lifetime spectroscopy (PALS).
③复合集流体中多层复合聚丙烯膜与金属层的粘结力：在一个1mm厚的铝箔上粘接一层Permacel P-94双面胶，在双面胶的上方粘接复合集流体，在复合集流体上方覆盖一层乙烯丙烯酸共聚物薄膜(杜邦Nurcel0903，厚度为50μm)，然后在1.3×105N/m2、120℃下热压10s，冷却至室温，裁成150mm×15mm的小条。最后将样品小条的乙烯丙烯酸共聚物薄膜固定于拉力机的上夹具，其余部分固定在下夹具，固定好后二者以180o的角度、100mm/min的速度进行剥离，测试剥离力，即多层复合聚丙烯膜与金属层的粘结力。③ The bonding strength between the multi-layer composite polypropylene film and the metal layer in the composite current collector: a layer of Permacel P-94 double-sided tape is bonded on a 1mm thick aluminum foil, the composite current collector is bonded on the double-sided tape, and a layer of ethylene acrylic acid copolymer film (DuPont Nurcel0903, thickness of 50μm) is covered on the composite current collector, and then hot-pressed at 1.3×105N/m2 and 120℃ for 10s, cooled to room temperature, and cut into 150mm×15mm strips. Finally, the ethylene acrylic acid copolymer film of the sample strip is fixed to the upper fixture of the tensile machine, and the rest is fixed to the lower fixture. After fixing, the two are peeled at an angle of 180o and a speed of 100mm/min to test the peeling force, that is, the bonding strength between the multi-layer composite polypropylene film and the metal layer.
④复合聚丙烯膜拉伸强度：测试参照国标GB/T 1040.3-2006。④ Tensile strength of composite polypropylene film: The test refers to the national standard GB/T 1040.3-2006.
⑤表层不良率：表面存在缺陷的聚丙烯膜的长度与制备的多层复合聚丙烯膜的总长度之比，其中表面存在缺陷的聚丙烯膜的长度由收卷前的光学缺陷检测***进行统计。⑤ Surface defect rate: the ratio of the length of the polypropylene film with surface defects to the total length of the prepared multi-layer composite polypropylene film, wherein the length of the polypropylene film with surface defects is counted by the optical defect detection system before winding.
性能测试结果见下表1：The performance test results are shown in Table 1 below:
表1


Table 1


备注：表中粘结力1及粘结力2分别表示多层复合聚丙烯膜的第一改性层、第二改性层与金属层的粘结力。Note: Adhesion 1 and Adhesion 2 in the table represent the adhesion between the first modified layer, the second modified layer and the metal layer of the multi-layer composite polypropylene film, respectively.
结果分析：Result analysis:
(1)由表1可知，相对于对比例1-2，实施例1-35的多层复合聚丙烯膜的表面张力更高，相对于对比例4，实施例1-35的多层复合聚丙烯膜的表面张力更加稳定，对比例3的多层复合聚丙烯膜的表面张力较高且稳定，但是拉伸强度很低。(1) It can be seen from Table 1 that the surface tension of the multilayer composite polypropylene film of Example 1-35 is higher than that of Comparative Example 1-2, and the surface tension of the multilayer composite polypropylene film of Example 1-35 is more stable than that of Comparative Example 4. The surface tension of the multilayer composite polypropylene film of Comparative Example 3 is relatively high and stable, but the tensile strength is very low.
(2)从实施例1-3和5、6可以看出：提升改性层中改性聚丙烯的含量，改性层的表面张力呈现增大的趋势、自由体积先增大后降低，二者共同作用导致了多层复合聚丙烯膜与金属层的粘结力先升高后降低；由于改性层中改性聚丙烯含量的增加，导致高分子的取向性和结晶度降低，最终导致多层复合聚丙烯膜的拉伸强度降低。(2) It can be seen from Examples 1-3 and 5 and 6 that: as the content of modified polypropylene in the modified layer is increased, the surface tension of the modified layer shows an increasing trend, and the free volume first increases and then decreases. The combined effect of the two causes the adhesion between the multilayer composite polypropylene film and the metal layer to first increase and then decrease. Due to the increase in the content of modified polypropylene in the modified layer, the orientation and crystallinity of the polymer decrease, which ultimately leads to a decrease in the tensile strength of the multilayer composite polypropylene film.
(3)从实施例2、7、8、9、10和对比例6可以看出：提升改性聚丙烯中极性分子的接枝率，聚丙烯分子中的极性分子含量增加，进而引起改性层的表面张力呈现增大的趋势；极性分子在聚丙烯分子中一方面起到扰乱分子排列规整性的作用，另一方面又起到结晶成核的作用，二者相互制约，导致了自由体积先增大后降低；表面张力及自由体积二者共同的作用导致了多层复合聚丙烯膜与金属层的粘结力先升高后降低；提升极性分子的接枝率，多层复合聚丙烯膜的拉伸强度先升高后降低；且当改性聚丙烯中极性分子的接枝率过高，容易造成表面形成缺陷，导致由于表面缺陷形成的不良率提升，且不良率的提升会导致制备的复合集流体中基膜与金属层的粘结力变差。 (3) It can be seen from Examples 2, 7, 8, 9, 10 and Comparative Example 6 that: by increasing the grafting rate of polar molecules in the modified polypropylene, the content of polar molecules in the polypropylene molecules increases, which in turn causes the surface tension of the modified layer to show an increasing trend; polar molecules in the polypropylene molecules, on the one hand, disrupt the regularity of molecular arrangement, and on the other hand, they play a role in crystallization nucleation, and the two restrict each other, resulting in the free volume first increasing and then decreasing; the combined effect of surface tension and free volume causes the adhesion between the multilayer composite polypropylene film and the metal layer to first increase and then decrease; by increasing the grafting rate of polar molecules, the tensile strength of the multilayer composite polypropylene film first increases and then decreases; and when the grafting rate of polar molecules in the modified polypropylene is too high, it is easy to cause surface defects, resulting in an increase in the defect rate due to surface defects, and the increase in the defect rate will cause the adhesion between the base film and the metal layer in the prepared composite current collector to deteriorate.
(4)从实施例7、11、12、13和14可以看出：提升改性层中改性聚丙烯的熔融指数，改性层的表面张力、自由体积均先升高后降低、二者共同作用导致了多层复合聚丙烯膜与金属层的粘结力先升高后降低。由于熔融指数的提升，改性聚丙烯的平均分子量降低，导致制备的多层复合聚丙烯膜的拉伸强度降低。且当改性聚丙烯的熔融指数过低，成膜性变差，容易造成表面形成缺陷，导致由于表面缺陷形成的不良率提升。(4) It can be seen from Examples 7, 11, 12, 13 and 14 that when the melt index of the modified polypropylene in the modified layer is increased, the surface tension and free volume of the modified layer are first increased and then decreased, and the combined effect of the two causes the adhesion between the multilayer composite polypropylene film and the metal layer to first increase and then decrease. Due to the increase in the melt index, the average molecular weight of the modified polypropylene is reduced, resulting in a decrease in the tensile strength of the prepared multilayer composite polypropylene film. When the melt index of the modified polypropylene is too low, the film-forming property deteriorates, which easily causes surface defects, resulting in an increase in the defect rate due to surface defects.
(5)从实施例11、15、16、17和18可以看出：提升改性层中改性聚丙烯的分子量分布指数，改性层的表面张力、自由体积均先升高后降低、二者共同作用导致了多层复合聚丙烯膜与金属层的粘结力先升高后降低。由于分子量分布指数的提升，改性聚丙烯分子中小分子的含量增加，导致制备的多层复合聚丙烯膜的拉伸强度降低。且当改性聚丙烯的分子量分布过低或者过高时，成膜性变差，容易造成表面形成缺陷，导致由于表面缺陷形成的不良率提升。(5) It can be seen from Examples 11, 15, 16, 17 and 18 that when the molecular weight distribution index of the modified polypropylene in the modified layer is increased, the surface tension and free volume of the modified layer are first increased and then decreased, and the combined effect of the two causes the adhesion between the multilayer composite polypropylene film and the metal layer to first increase and then decrease. Due to the increase in the molecular weight distribution index, the content of small molecules in the modified polypropylene molecules increases, resulting in a decrease in the tensile strength of the prepared multilayer composite polypropylene film. When the molecular weight distribution of the modified polypropylene is too low or too high, the film-forming property deteriorates, which easily causes surface defects, resulting in an increase in the defect rate due to surface defects.
(6)从实施例15、19、20、21和22可以看出：提升多层复合聚丙烯膜的纵向拉伸倍率，改性层表面张力变化先略有升高后略有降低，自由体积呈现降低的趋势，这是由于高分子的取向性提高所致，二者的共同作用导致多层复合聚丙烯膜与金属层的粘结力先升高后降低。并且，由于多层复合聚丙烯膜的纵向拉伸倍率的提升，将导致多层复合聚丙烯膜的拉伸强度随之提升，但拉伸强度过高，容易造成表面形成缺陷，导致由于表面缺陷形成的不良率提升。(6) It can be seen from Examples 15, 19, 20, 21 and 22 that when the longitudinal stretching ratio of the multilayer composite polypropylene film is increased, the surface tension of the modified layer first increases slightly and then decreases slightly, and the free volume shows a decreasing trend. This is due to the improvement of the orientation of the polymer. The combined effect of the two causes the adhesion between the multilayer composite polypropylene film and the metal layer to first increase and then decrease. In addition, due to the increase in the longitudinal stretching ratio of the multilayer composite polypropylene film, the tensile strength of the multilayer composite polypropylene film will also increase. However, if the tensile strength is too high, it is easy to cause surface defects, resulting in an increase in the defect rate due to surface defects.
(7)从实施例1、26、27、28和29可以看出：提升改性层中改性聚丙烯的等规度，改性层表面张力先升高后降低，改性层自由体积降低，二者共同作用导致多层复合聚丙烯膜与金属层的粘结力先升高后降低；并且，由于改性层中改性聚丙烯的等规度提升，改性层中的高分子排列规整性提高，将导致多层复合聚丙烯膜的拉伸强度提升。另外，当改性层中改性聚丙烯的等规度过低时， 成膜性较差，容易造成表面形成缺陷，导致由于表面缺陷形成的不良率提升。(7) It can be seen from Examples 1, 26, 27, 28 and 29 that when the isotacticity of the modified polypropylene in the modified layer is increased, the surface tension of the modified layer first increases and then decreases, and the free volume of the modified layer decreases. The combined effect of the two causes the adhesion between the multilayer composite polypropylene film and the metal layer to first increase and then decrease. In addition, since the isotacticity of the modified polypropylene in the modified layer is increased, the regularity of the polymer arrangement in the modified layer is improved, which will lead to an increase in the tensile strength of the multilayer composite polypropylene film. In addition, when the isotacticity of the modified polypropylene in the modified layer is too low, The film-forming property is poor, which easily causes surface defects, resulting in an increase in the defective rate due to surface defects.
(8)从实施例1、30和31可以看出：芯层中聚丙烯的等规度对改性层的表面张力及自由体积基本没有影响，主要影响制备的多层复合聚丙烯膜的拉伸强度，芯层中聚丙烯的等规度越高，聚丙烯高分子更易发生取向及结晶，从而制备的多层复合聚丙烯膜的拉伸强度越高。(8) It can be seen from Examples 1, 30 and 31 that the isotacticity of the polypropylene in the core layer has little effect on the surface tension and free volume of the modified layer, but mainly affects the tensile strength of the prepared multi-layer composite polypropylene film. The higher the isotacticity of the polypropylene in the core layer, the easier it is for the polypropylene polymer to be oriented and crystallized, thereby the higher the tensile strength of the prepared multi-layer composite polypropylene film.
(9)从实施例1、4、23、32和33可以看出：提升改性层、芯层中抗氧化剂的含量，制备的多层复合聚丙烯膜的拉伸强度基本呈现先增加后基本不变的趋势，这是由于抗氧化剂含量的提升，可以降低聚丙烯熔融过程中的降解率，从而使得聚丙烯的平均分子量的降低值变小。而改性层、芯层中抗氧化剂的含量的提升对改性层的表面张力及自由体积基本没有影响。(9) It can be seen from Examples 1, 4, 23, 32 and 33 that the tensile strength of the prepared multi-layer composite polypropylene film basically shows a trend of first increasing and then remaining basically unchanged when the content of the antioxidant in the modified layer and the core layer is increased. This is because the increase in the content of the antioxidant can reduce the degradation rate of polypropylene during the melting process, thereby reducing the decrease in the average molecular weight of polypropylene. However, the increase in the content of the antioxidant in the modified layer and the core layer has little effect on the surface tension and free volume of the modified layer.
(10)从实施例19、24、25、36、37及38可以看出：利用其他改性的聚丙烯依然可以取得良好的发明效果，尤其是低聚物改性的聚丙烯与小分子改性的聚丙烯的组合物。(10) It can be seen from Examples 19, 24, 25, 36, 37 and 38 that good inventive effects can still be achieved using other modified polypropylenes, especially the combination of oligomer-modified polypropylene and small molecule-modified polypropylene.
(11)从实施例1与对比例5可以看出，与一步拉伸到位相比，采用多次拉伸处理可以使得制备的多层复合聚丙烯膜的拉伸强度更优、不良率更低。(11) It can be seen from Example 1 and Comparative Example 5 that, compared with one-step stretching, multiple stretching treatments can make the prepared multi-layer composite polypropylene film have better tensile strength and lower defective rate.
2、为了验证本发明制备的复合集流体在电池应用过程的效果，并与传统复合集流体的应用效果进行对比，这里以实施例1、2、3及对比例1制备的复合集流体样品为电池的电极集流体，以磷酸铁锂为正极材料、石墨为负极材料、碳酸酯为电解液，制备出软包电池，制备的电池在0.5C的充放电倍率下进行循环实验，能量密度(单位质量活性电极材料)随循环次数的变化如图5所示。2. In order to verify the effect of the composite current collector prepared by the present invention in the battery application process and compare it with the application effect of the traditional composite current collector, the composite current collector samples prepared in Examples 1, 2, 3 and Comparative Example 1 are used as the electrode current collectors of the battery, and lithium iron phosphate is used as the positive electrode material, graphite is used as the negative electrode material, and carbonate is used as the electrolyte to prepare soft-pack batteries. The prepared batteries are subjected to cycle experiments at a charge and discharge rate of 0.5C, and the changes in energy density (unit mass of active electrode material) with the number of cycles are shown in Figure 5.
从图5可以看出：与传统的复合集流体相比，以本发明制备的复合集流体样品为电池集流体制备的电池的能量密度在循环过程中的衰减变缓，即电池充放电循环性能得到提升，这得益于其基膜与金属层粘结力提升所带来的结构稳 定性。As can be seen from Figure 5, compared with the traditional composite current collector, the energy density of the battery prepared with the composite current collector sample prepared in the present invention as the battery current collector decays more slowly during the cycle, that is, the battery charge and discharge cycle performance is improved, which is due to the structural stability brought about by the improved adhesion between the base film and the metal layer. Qualitative.
以上所述实施例的各技术特征可以进行任意的组合，为使描述简洁，未对上述实施例中的各个技术特征所有可能的组合都进行描述，然而，只要这些技术特征的组合不存在矛盾，都应当认为是本说明书记载的范围。The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
以上所述实施例仅表达了本发明的几种实施方式，其描述较为具体和详细，但并不能因此而理解为对发明专利范围的限制。应当指出的是，对于本领域的普通技术人员来说，在不脱离本发明构思的前提下，还可以做出若干变形和改进，这些都属于本发明的保护范围。因此，本发明专利的保护范围应以所附权利要求为准。 The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims (25)

  1. 一种多层复合聚丙烯材料，其特征在于，其结构包括呈层叠设置的第一改性层，芯层和第二改性层；A multi-layer composite polypropylene material, characterized in that its structure comprises a first modified layer, a core layer and a second modified layer which are stacked;
    所述第一改性层包括第一改性聚丙烯；The first modified layer includes a first modified polypropylene;
    所述芯层包括聚丙烯；The core layer comprises polypropylene;
    所述第二改性层包括第二改性聚丙烯；The second modified layer includes a second modified polypropylene;
    所述第一改性聚丙烯和第二改性聚丙烯分别独立选自小分子接枝改性的聚丙烯和低聚物接枝改性的聚丙烯中的一种或多种。The first modified polypropylene and the second modified polypropylene are independently selected from one or more of small molecule graft-modified polypropylene and oligomer graft-modified polypropylene.
  2. 根据权利要求1所述的多层复合聚丙烯材料，其特征在于，The multi-layer composite polypropylene material according to claim 1, characterized in that:
    所述小分子接枝改性的聚丙烯选自顺丁烯二酸酐接枝改性的聚丙烯、丙烯酸-顺丁烯二酸酐接枝改性的聚丙烯、二乙烯三胺-甲基丙烯酸缩水甘油酯接枝改性的聚丙烯、丙烯酰胺接枝改性的聚丙烯、丙烯酰胺-丙烯酸接枝改性聚丙烯、琥珀酸酐接枝聚丙烯、琥珀酰荧光素-琥珀酸酐接枝的聚丙烯和极性改性分子中的氢被甲基、乙基或卤素原子取代的改性聚丙烯中的一种或多种；和/或The small molecule grafted modified polypropylene is selected from one or more of maleic anhydride grafted modified polypropylene, acrylic acid-maleic anhydride grafted modified polypropylene, diethylenetriamine-glycidyl methacrylate grafted modified polypropylene, acrylamide grafted modified polypropylene, acrylamide-acrylic acid grafted modified polypropylene, succinic anhydride grafted polypropylene, succinylfluorescein-succinic anhydride grafted polypropylene and modified polypropylene in which hydrogen in the polar modified molecule is replaced by methyl, ethyl or halogen atoms; and/or
    所述低聚物接枝改性的聚丙烯选自顺丁烯二酸酐低聚物接枝改性的聚丙烯、(丙烯酸-顺丁烯二酸酐)低聚物接枝改性的聚丙烯、二(乙烯三胺-甲基丙烯酸缩水甘油酯)低聚物接枝改性的聚丙烯、丙烯酰胺低聚物接枝改性的聚丙烯、(丙烯酰胺-丙烯酸)低聚物接枝改性聚丙烯、琥珀酸酐低聚物接枝聚丙烯、(琥珀酰荧光素-琥珀酸酐)低聚物接枝的聚丙烯和极性改性分子中的氢被甲基、乙基或卤素原子取代的改性聚丙烯中的一种或多种。The oligomer grafted modified polypropylene is selected from one or more of maleic anhydride oligomer grafted modified polypropylene, (acrylic acid-maleic anhydride) oligomer grafted modified polypropylene, di(ethylenetriamine-glycidyl methacrylate) oligomer grafted modified polypropylene, acrylamide oligomer grafted modified polypropylene, (acrylamide-acrylic acid) oligomer grafted modified polypropylene, succinic anhydride oligomer grafted polypropylene, (succinylfluorescein-succinic anhydride) oligomer grafted polypropylene and modified polypropylene in which hydrogen in the polar modified molecule is replaced by methyl, ethyl or halogen atoms.
  3. 根据权利要求1或2所述的多层复合聚丙烯材料，其特征在于，所述第一改性聚丙烯和所述第二改性聚丙烯的接枝率g满足：0.1％≤g≤2％。The multilayer composite polypropylene material according to claim 1 or 2, characterized in that the grafting rate g of the first modified polypropylene and the second modified polypropylene satisfies: 0.1%≤g≤2%.
  4. 根据权利要求1至3任一项所述的多层复合聚丙烯材料，其特征在于，所述第一改性聚丙烯的熔融指数约为(3.1-4.1)g/10min/(230℃/2.16kg)，分子量 分布指数约为4.5-5.6。The multilayer composite polypropylene material according to any one of claims 1 to 3, characterized in that the melt index of the first modified polypropylene is about (3.1-4.1) g/10min/(230°C/2.16kg), and the molecular weight is The distribution index is approximately 4.5-5.6.
  5. 根据权利要求1至4任一项所述的多层复合聚丙烯材料，其特征在于，所述第二改性聚丙烯的熔融指数约为(3.2-4.0)g/10min/(230℃/2.16kg)，分子量分布指数约为4.5-5.6。The multilayer composite polypropylene material according to any one of claims 1 to 4 is characterized in that the melt index of the second modified polypropylene is approximately (3.2-4.0) g/10 min/(230°C/2.16 kg) and the molecular weight distribution index is approximately 4.5-5.6.
  6. 根据权利要求1至5任一项所述的多层复合聚丙烯材料，其特征在于，所述芯层中聚丙烯的熔融指数约为(3.0-3.9)g/10min/(230℃/2.16kg)，分子量分布指数约为4.5-5.2，等规度约≥97％。The multilayer composite polypropylene material according to any one of claims 1 to 5 is characterized in that the melt index of the polypropylene in the core layer is about (3.0-3.9) g/10 min/(230°C/2.16 kg), the molecular weight distribution index is about 4.5-5.2, and the isotacticity is about ≥97%.
  7. 根据权利要求1至6任一项所述的多层复合聚丙烯材料，其特征在于，在所述第一改性层中，所述第一改性聚丙烯的质量百分含量约≥20％。The multi-layer composite polypropylene material according to any one of claims 1 to 6, characterized in that, in the first modified layer, the mass percentage of the first modified polypropylene is about ≥ 20%.
  8. 根据权利要求7所述的多层复合聚丙烯材料，其特征在于，所述第一改性层中还包括第一聚丙烯和第一抗氧化剂；The multi-layer composite polypropylene material according to claim 7, characterized in that the first modified layer further comprises a first polypropylene and a first antioxidant;
    以质量百分含量计，所述第一改性层中包括所述第一聚丙烯约0％-79.8％，所述第一改性聚丙烯约20％-99.9％以及所述第一抗氧化剂约0.1％-0.6％。In terms of mass percentage, the first modified layer includes about 0%-79.8% of the first polypropylene, about 20%-99.9% of the first modified polypropylene and about 0.1%-0.6% of the first antioxidant.
  9. 根据权利要求8所述的多层复合聚丙烯材料，其特征在于，所述第一聚丙烯的熔融指数约为(3.0-3.9)g/10min/(230℃/2.16kg)，分子量分布指数约为4.5-5.2，等规度约为89％-97％。The multilayer composite polypropylene material according to claim 8 is characterized in that the melt index of the first polypropylene is approximately (3.0-3.9) g/10min/(230°C/2.16kg), the molecular weight distribution index is approximately 4.5-5.2, and the isotacticity is approximately 89%-97%.
  10. 根据权利要求8或9所述的多层复合聚丙烯材料，其特征在于，所述第一抗氧化剂选自亚磷酸三苯酯、丁基羟基茴香醚、2,6-二叔丁基-4-甲基苯酚和对叔丁基邻苯二酚中的一种或多种。The multilayer composite polypropylene material according to claim 8 or 9 is characterized in that the first antioxidant is selected from one or more of triphenyl phosphite, butylated hydroxyanisole, 2,6-di-tert-butyl-4-methylphenol and p-tert-butylcatechol.
  11. 根据权利要求1至10任一项所述的多层复合聚丙烯材料，其特征在于，在所述第二改性层中，所述第二改性聚丙烯的质量百分含量约≥20％。The multi-layer composite polypropylene material according to any one of claims 1 to 10, characterized in that, in the second modified layer, the mass percentage of the second modified polypropylene is about ≥ 20%.
  12. 根据权利要求11所述的多层复合聚丙烯材料，其特征在于，所述第二改性层中还包括第二聚丙烯和第二抗氧化剂； The multi-layer composite polypropylene material according to claim 11, characterized in that the second modified layer further comprises a second polypropylene and a second antioxidant;
    以质量百分含量计，所述第二改性层中包括所述第二聚丙烯约0％-79.8％，所述第二改性聚丙烯约20％-99.9％以及所述第二抗氧化剂约0.1％-0.6％。In terms of mass percentage, the second modified layer includes about 0%-79.8% of the second polypropylene, about 20%-99.9% of the second modified polypropylene and about 0.1%-0.6% of the second antioxidant.
  13. 根据权利要求12所述的多层复合聚丙烯材料，其特征在于，所述第二聚丙烯的熔融指数约为(3.0-3.9)g/10min/(230℃/2.16kg)，分子量分布指数约为4.5-5.2，等规度约为89％-97％。The multilayer composite polypropylene material according to claim 12 is characterized in that the melt index of the second polypropylene is approximately (3.0-3.9) g/10min/(230°C/2.16kg), the molecular weight distribution index is approximately 4.5-5.2, and the isotacticity is approximately 89%-97%.
  14. 根据权利要求12或13所述的多层复合聚丙烯材料，其特征在于，所述第二抗氧化剂选自亚磷酸三苯酯、丁基羟基茴香醚、2,6-二叔丁基-4-甲基苯酚和对叔丁基邻苯二酚中的一种或多种。The multilayer composite polypropylene material according to claim 12 or 13, characterized in that the second antioxidant is selected from one or more of triphenyl phosphite, butylated hydroxyanisole, 2,6-di-tert-butyl-4-methylphenol and p-tert-butylcatechol.
  15. 根据权利要求1至14任一项所述的多层复合聚丙烯材料，其特征在于，所述芯层还包括第三抗氧化剂；The multilayer composite polypropylene material according to any one of claims 1 to 14, characterized in that the core layer further comprises a third antioxidant;
    以质量百分含量计，所述芯层中包括所述聚丙烯约99.5％-99.8％以及第三抗氧化剂约0.2％-0.5％。In terms of mass percentage, the core layer includes about 99.5%-99.8% of the polypropylene and about 0.2%-0.5% of the third antioxidant.
  16. 根据权利要求15所述的多层复合聚丙烯材料，其特征在于，所述第三抗氧化剂选自亚磷酸三苯酯、丁基羟基茴香醚、2,6-二叔丁基-4-甲基苯酚和对叔丁基邻苯二酚中的一种或多种。The multilayer composite polypropylene material according to claim 15 is characterized in that the third antioxidant is selected from one or more of triphenyl phosphite, butylated hydroxyanisole, 2,6-di-tert-butyl-4-methylphenol and p-tert-butylcatechol.
  17. 根据权利要求1至16任一项所述的多层复合聚丙烯材料，其特征在于，所述多层复合聚丙烯材料的厚度约≥1μm，其中，所述第一改性层和第二改性层的厚度占比分别独立约为5％-15％，所述芯层的厚度占比约为70％-90％。The multilayer composite polypropylene material according to any one of claims 1 to 16 is characterized in that the thickness of the multilayer composite polypropylene material is about ≥1 μm, wherein the thickness of the first modified layer and the second modified layer account for about 5%-15% respectively, and the thickness of the core layer accounts for about 70%-90%.
  18. 一种权利要求1至17任一项所述的多层复合聚丙烯材料的制备方法，其特征在于，包括如下步骤：A method for preparing the multilayer composite polypropylene material according to any one of claims 1 to 17, characterized in that it comprises the following steps:
    在约200-260℃条件下熔融包含所述第一改性聚丙烯的原料，在约230-260℃条件下挤出制备第一改性层中间体；Melting the raw material containing the first modified polypropylene at a temperature of about 200-260° C., and extruding at a temperature of about 230-260° C. to prepare a first modified layer intermediate;
    在约200-260℃条件下熔融包含所述聚丙烯的原料，在约230-260℃条件下 挤出制备芯层中间体；The raw material containing the polypropylene is melted at about 200-260°C, and the raw material containing the polypropylene is melted at about 230-260°C. Extrusion to prepare a core layer intermediate;
    在约200-260℃条件下熔融包含所述第二改性聚丙烯的原料，在约230-260℃条件下挤出制备第二改性层中间体；Melting the raw material containing the second modified polypropylene at a temperature of about 200-260° C., and extruding at a temperature of about 230-260° C. to prepare a second modified layer intermediate;
    在约15-60℃条件下通过制片工艺将所述第一改性层中间体、芯层中间体和第二改性层中间体复合成型制备多层复合聚丙烯材料中间体；The first modified layer intermediate, the core layer intermediate and the second modified layer intermediate are composite-molded by a sheet-making process at about 15-60° C. to prepare a multi-layer composite polypropylene material intermediate;
    对所述多层复合聚丙烯材料中间体进行同步拉伸处理制备所述多层复合聚丙烯材料，且纵向总拉伸比约为5-9倍、横向总拉伸比约为4-8倍。The multi-layer composite polypropylene material intermediate is subjected to synchronous stretching treatment to prepare the multi-layer composite polypropylene material, and the total longitudinal stretching ratio is about 5-9 times and the total transverse stretching ratio is about 4-8 times.
  19. 根据权利要求18所述的多层复合聚丙烯材料的制备方法，其特征在于，所述同步拉伸包括如下步骤：The method for preparing a multi-layer composite polypropylene material according to claim 18, characterized in that the synchronous stretching comprises the following steps:
    逐步升温，分别在约152-157℃、约156-160℃、约159-162℃条件下对所述多层复合聚丙烯材料中间体进行第一拉伸处理、第二拉伸处理和第三拉伸处理，制备多层复合聚丙烯材料中间体I；gradually raising the temperature to perform a first stretching treatment, a second stretching treatment and a third stretching treatment on the multilayer composite polypropylene material intermediate at about 152-157° C., about 156-160° C. and about 159-162° C., respectively, to prepare a multilayer composite polypropylene material intermediate I;
    逐步升温，分别在约162-165℃、约162-169℃条件下对所述多层复合聚丙烯材料中间体I进行第一热定型处理和第二热定型处理，制备所述多层复合聚丙烯材料。The temperature is gradually increased, and the multilayer composite polypropylene material intermediate I is subjected to a first heat setting treatment and a second heat setting treatment at about 162-165° C. and about 162-169° C., respectively, to prepare the multilayer composite polypropylene material.
  20. 一种权利要求1至17任一项所述的多层复合聚丙烯材料的制备方法，其特征在于，包括如下步骤：A method for preparing the multilayer composite polypropylene material according to any one of claims 1 to 17, characterized in that it comprises the following steps:
    在约200-260℃条件下熔融包含所述第一改性聚丙烯的原料，在约230-260℃条件下挤出制备第一改性层中间体；Melting the raw material containing the first modified polypropylene at a temperature of about 200-260° C., and extruding at a temperature of about 230-260° C. to prepare a first modified layer intermediate;
    在约200-260℃条件下熔融包含所述聚丙烯的原料，在约230-260℃条件下挤出制备芯层中间体；Melting the raw material containing the polypropylene at a temperature of about 200-260° C., and extruding at a temperature of about 230-260° C. to prepare a core layer intermediate;
    在约200-260℃条件下熔融包含所述第二改性聚丙烯的原料，在约230-260℃条件下挤出制备第二改性层中间体； Melting the raw material containing the second modified polypropylene at a temperature of about 200-260° C., and extruding at a temperature of about 230-260° C. to prepare a second modified layer intermediate;
    在约15-60℃条件下通过制片工艺将所述第一改性层中间体、芯层中间体和第二改性层中间体复合成型制备多层复合聚丙烯材料中间体；The first modified layer intermediate, the core layer intermediate and the second modified layer intermediate are composite-molded by a sheet-making process at about 15-60° C. to prepare a multi-layer composite polypropylene material intermediate;
    对所述多层复合聚丙烯材料中间体进行异步拉伸处理制备所述多层复合聚丙烯材料，且纵向总拉伸比约为5-9倍、横向总拉伸比约为4-8倍。The multi-layer composite polypropylene material intermediate is subjected to asynchronous stretching treatment to prepare the multi-layer composite polypropylene material, and the total longitudinal stretching ratio is about 5-9 times and the total transverse stretching ratio is about 4-8 times.
  21. 根据权利要求20所述的多层复合聚丙烯材料的制备方法，其特征在于，所述异步拉伸包括如下步骤：The method for preparing a multilayer composite polypropylene material according to claim 20, characterized in that the asynchronous stretching comprises the following steps:
    在约145-155℃条件下对所述多层复合聚丙烯材料中间体进行纵向拉伸处理，制备多层复合聚丙烯材料中间体II；Performing a longitudinal stretching treatment on the multi-layer composite polypropylene material intermediate at a temperature of about 145-155° C. to prepare a multi-layer composite polypropylene material intermediate II;
    在约150-160℃条件下对所述多层复合聚丙烯材料II中间体进行横向拉伸处理，制备多层复合聚丙烯材料中间体III；Performing a transverse stretching treatment on the multilayer composite polypropylene material II intermediate at about 150-160° C. to prepare a multilayer composite polypropylene material intermediate III;
    在约165-170℃条件下对所述多层复合聚丙烯材料III进行热成型处理，制备多层复合聚丙烯材料IV；Performing a thermoforming treatment on the multi-layer composite polypropylene material III at a temperature of about 165-170° C. to prepare a multi-layer composite polypropylene material IV;
    在约120-135℃条件下对所述多层复合聚丙烯材料IV进行热处理，制备所述多层复合聚丙烯材料。The multi-layer composite polypropylene material IV is heat-treated at about 120-135° C. to prepare the multi-layer composite polypropylene material.
  22. 一种复合集流体，其特征在于，其结构包括呈层叠设置的第一保护层，第一金属层，支撑层，第二金属层和第二保护层；A composite current collector, characterized in that its structure comprises a first protective layer, a first metal layer, a support layer, a second metal layer and a second protective layer arranged in layers;
    所述支撑层包括根据权利要求1至17任一项所述的多层复合聚丙烯材料，或根据权利要求18至21任一项所述的制备方法制得的多层复合聚丙烯材料。The support layer comprises the multi-layer composite polypropylene material according to any one of claims 1 to 17, or the multi-layer composite polypropylene material prepared by the preparation method according to any one of claims 18 to 21.
  23. 根据权利要求22所述的复合集流体，其特征在于，所述第一保护层和第二保护层分别独立包括不活泼金属及其合金、金属氧化物和碳材料中的一种或多种；The composite current collector according to claim 22, characterized in that the first protective layer and the second protective layer independently include one or more of inactive metals and alloys thereof, metal oxides and carbon materials;
    所述第一金属层和第二金属层分别独立包括电阻率约≤8×10-8Ω·m的金属及其合金中的一种或多种。 The first metal layer and the second metal layer independently include one or more metals and alloys thereof with a resistivity of about ≤8×10-8Ω·m.
  24. 一种极片，其特征在于，包括权利要求22或23所述的复合集流体。A pole piece, characterized by comprising the composite current collector according to claim 22 or 23.
  25. 一种电池，其特征在于，包括权利要求24所述的极片。 A battery, characterized by comprising the pole piece according to claim 24.
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