High-performance composite film for packaging battery of unmanned aerial vehicle

Abstract

The invention relates to the technical field of unmanned aerial vehicle battery packaging materials, and discloses a high-performance composite film for unmanned aerial vehicle battery packaging, which is specifically prepared by the following steps: preparing alkynylated PA6 / PET composite resin by taking an epoxy compatilizer, PA6, PET and 3-propargyl bromide as raw materials; the preparation method comprises the following steps: carrying out melt grafting modification treatment on LLDPE (Linear Low Density Polyethylene) by using tetramethyl tetravinyl cyclotetrasiloxane, oxidizing an alkenyl functional group into an epoxy functional group, and reacting with sodium azide to prepare azide polyethylene resin; the polyethylene resin and alkynylated PA6 / PET composite resin are subjected to a click reaction to prepare PA6 / PET / LLDPE composite resin, and the PA6 / PET / LLDPE composite resin is subjected to blow molding to prepare the PA6 / PET / LLDPE composite film. The PA6 / PET / LLDPE composite film prepared by the invention has excellent mechanical properties, and can be used as an outer layer of an aluminum plastic film to prepare a high-performance composite film for packaging an unmanned aerial vehicle battery, so that the production cost of the aluminum plastic film is effectively reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of unmanned aerial vehicle battery packaging materials, in particular to a high-performance composite film for unmanned aerial vehicle battery packaging. BACKGROUND

[0002] With the wide application of unmanned aerial vehicle technology in surveying and mapping, agriculture, logistics, security and consumer entertainment fields, the performance and safety requirements of the core energy unit-battery pack are increasingly improved. Unmanned aerial vehicle batteries are usually high-energy-density lithium-ion or lithium-polymer batteries, and their characteristics determine that they have extremely stringent requirements for packaging materials.

[0003] At present, the common battery packaging material on the market is an aluminum plastic film, which has the following structure: outer layer (polyethylene terephthalate or polyamide), adhesive layer (polyurethane or modified polyethylene acrylic adhesive), barrier layer (aluminum foil), adhesive layer (polyurethane or modified polyethylene acrylic adhesive), inner layer (cast polypropylene or modified polyethylene). Since the battery will frequently bear vibration, impact and possible puncture risk during the take-off, flight and transportation of the unmanned aerial vehicle, the outer layer needs to provide all-round physical protection for the battery to resist mechanical stress during transportation, loading and unloading and use.

[0004] However, the toughness of PET (polyethylene terephthalate) in the outer layer material is poor, and the raw material cost of PA6 (polyamide 6) is high. LLDPE (linear low-density polyethylene) not only has high toughness, but also has low raw material cost. Therefore, LLDPE is used to replace part of PET and PA6 in the outer layer structure design to improve the toughness of the aluminum plastic film and reduce the production cost.

[0005] Research has found that the compatibility between LLDPE, PET and PA6 is poor, and phase separation easily occurs, which cannot achieve good interface bonding, thereby causing the tensile strength, puncture resistance and other properties of the composite film to decrease. SUMMARY

[0006] In order to improve the compatibility between LLDPE, PET and PA6, the alkyne-modified PA6 / PET composite resin and azido polyethylene resin are designed and synthesized in the present application. Through the "click" reaction of azido-alkyne, the azido polyethylene resin is grafted to the alkyne-modified PA6 / PET composite resin in the form of covalent bond to prepare PA6 / PET / LLDPE composite resin. Further, through the blow molding process, the PA6 / PET / LLDPE composite film with excellent mechanical properties is prepared, and the production cost of the aluminum plastic film is reduced by replacing part of PET and PA6.

[0007] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0008] The application discloses a high-performance composite film for unmanned aerial vehicle battery packaging and a preparation method thereof.

[0009] Step one: under the action of an initiator, tetramethyltetra-vinylcyclotetrasiloxane is used for melt grafting modification treatment of LLDPE resin, and alkenyl functional groups in the LLDPE resin are oxidized into epoxy functional groups, and finally, ring-opening reaction occurs with sodium azide to obtain azidized polyethylene resin;

[0010] Step two: under the action of a cuprous halide, click reaction occurs between the alkyne functional groups in the alkyne-modified PA6 / PET composite resin and the azido groups in the azidized polyethylene resin, and the LLDPE resin is grafted onto the PA6 / PET composite resin in the form of a covalent bond, and finally, a PA6 / PET / LLDPE composite film is prepared through a blow molding process;

[0011] Step three: the PA6 / PET / LLDPE composite film is compounded with an adhesive layer, a barrier layer and an inner layer to obtain the high-performance composite film.

[0012] Preferably, the preparation method of the alkyne-modified PA6 / PET composite resin comprises the following steps:

[0013] PA6 resin and PET resin are in-situ compatibilized by using an epoxy-type compatibilizer, and a chain extension reaction occurs to obtain a hydroxyl-functionalized PA6 / PET composite master batch;

[0014] Under the action of an alkali catalyst, the hydroxyl-functionalized PA6 / PET composite master batch is subjected to a substitution reaction with 3-bromopropargyl to obtain the alkyne-modified PA6 / PET composite resin.

[0015] Preferably, the mass ratio of the PA6 resin to the PET resin in the hydroxyl-functionalized PA6 / PET composite master batch is 8:1-3, and the amount of the epoxy-type compatibilizer is 5-10% of the total mass of the PA6 resin and the PET resin.

[0016] Preferably, the epoxy-type compatibilizer is one of ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether and 1,4-butanediol diglycidyl ether.

[0017] Preferably, the alkali catalyst is one of potassium hydroxide and sodium hydroxide.

[0018] Preferably, the initiator is one of dicumyl peroxide and tert-butyl peroxybenzoate.

[0019] Preferably, the cuprous halide is one of cuprous bromide, cuprous chloride and cuprous iodide.

[0020] Preferably, the process parameters of the extruder used in the blow molding process are: barrel three-zone temperature: 210-230 DEG C, 240-260 DEG C, 240-260 DEG C, head temperature: 230-250 DEG C, screw rotation speed: 25-35 r / min.

[0021] Preferably, the mass ratio of the acetylenylated PA6 / PET composite resin to the azidated polyethylene resin in the PA6 / PET / LLDPE composite film is 75-85:15-25.

[0022] Preferably, the thickness of the PA6 / PET / LLDPE composite film is 10-25 mu m.

[0023] The present application has the following beneficial effects:

[0024] Based on the mechanism of epoxy ring-opening reaction and substitution reaction, the acetylenylated PA6 / PET composite resin is prepared from the epoxy type compatibilizer, PA6 resin, PET resin and 3-bromopropargyl.

[0025] Under the action of the initiator, the LLDPE resin is modified by melt grafting with tetramethyltetravinylcyclotetrasiloxane, the alkenyl functional group is introduced into the LLDPE resin, and the alkenyl functional group is oxidized into an epoxy functional group, and finally the sodium azide is reacted by the epoxy ring-opening azidation reaction to prepare the azidated polyethylene resin.

[0026] Based on the mechanism of azide-acetylenyl "click" reaction, the PA6 / PET / LLDPE composite resin is prepared from the acetylenylated PA6 / PET composite resin and the azidated polyethylene resin under the action of halogenated cuprous, and then the PA6 / PET / LLDPE composite film is prepared by the blow molding process.

[0027] The experimental results prove that the PA6 / PET / LLDPE composite film prepared by the present application has significantly improved beneficial technical effects in toughness, and the composite film does not significantly decrease in tensile strength and puncture resistance;

[0028] The PA6 / PET / LLDPE composite film is compounded with an adhesive layer, a barrier layer and an inner layer to prepare a high-performance composite film for packaging unmanned aerial vehicle batteries, and effectively reduces the production cost of aluminum plastic film. DETAILED DESCRIPTION

[0029] Example one:

[0030] The preparation of the acetylenylated PA6 / PET composite resin comprises the following steps:

[0031] Step S1: preparing the hydroxyl-functionalized PA6 / PET composite master batch, the preparation mechanism of which is that the epoxy groups in 1,4-butanediol diglycidyl ether react with the polar functional groups at the molecular chain ends of PA6 resin and PET resin to prepare the hydroxyl-functionalized PA6 / PET composite master batch, and the specific experimental steps are as follows: 80 g of PA6 resin (model F136 / NA99001 / 4229D), 20 g of PET resin (brand 70G43L), and 0.8 g of 1,4-butanediol diglycidyl ether are added into a high-speed mixer, mixed for 5 min, and then placed in an extruder for melt extrusion granulation, wherein the screw rotation speed of the extruder is 200 r / min, the temperature of zone 1 is 230°C, the temperature of zone 2 is 240°C, the temperature of zone 3 is 250°C, and the temperature of zone 4 is 260°C, to prepare the hydroxyl-functionalized PA6 / PET composite master batch;

[0032] Step S2: preparing the acetylenyl-functionalized PA6 / PET composite resin, the preparation mechanism of which is that the hydroxyl groups in the hydroxyl-functionalized PA6 / PET composite master batch react with the bromine functional groups in 3-bromopropargyl to prepare the acetylenyl-functionalized PA6 / PET composite resin, and the specific experimental steps are as follows: 20 g of the hydroxyl-functionalized PA6 / PET composite master batch and 2.81 g of potassium hydroxide are added into 100 mL of dimethyl sulfoxide under nitrogen protection, stirred for 2 h in an ice bath, then 5.95 g of 3-bromopropargyl is added, after the addition, the temperature of the system is increased to 80°C, and the reaction is carried out for 20 h, after the reaction is completed, filtration, washing, and drying at 60°C for 10 h are performed to prepare the acetylenyl-functionalized PA6 / PET composite resin.

[0033] Example Two

[0034] The preparation of the azidized polyethylene resin includes the following steps:

[0035] Step SS1: preparing the polyethylene resin containing alkenyl functional groups, the preparation mechanism of which is that tetramethyltetra-vinylcyclotetrasiloxane is used for melt grafting modification treatment of LLDPE resin under the action of dicumyl peroxide initiator to prepare the polyethylene resin containing alkenyl functional groups, which includes the following raw materials in parts by weight: 100 parts of LLDPE resin (model 7042); 8 parts of tetramethyltetra-vinylcyclotetrasiloxane; and 0.1 part of dicumyl peroxide;

[0036] The preparation method of the polyethylene resin containing alkenyl functional groups is as follows: the LLDPE resin, tetramethyltetra-vinylcyclotetrasiloxane, and dicumyl peroxide are added into a high-speed mixer, uniformly mixed, and the mixed material is placed in a twin-screw extruder for melt extrusion granulation, wherein the screw rotation speed of the twin-screw extruder is 150 r / min, and the temperature of zones 1-4 is 130°C, 150°C, 170°C, and 180°C, respectively, to prepare the polyethylene resin containing alkenyl functional groups.

[0037] Step SS2: preparing the polyethylene resin containing epoxy group, the preparation mechanism is that the alkenyl functional group in the polyethylene resin containing alkenyl functional group is oxidized into epoxy functional group under the action of glacial acetic acid and hydrogen peroxide, and the polyethylene resin containing epoxy group is prepared, and the specific experimental steps are as follows: 20 g of polyethylene resin containing alkenyl functional group is added into 100 mL of toluene, the temperature is raised to 80℃, and stirring is performed until dissolution, 20 mL of glacial acetic acid and 1 mL of concentrated sulfuric acid are added, the temperature of the system is controlled at 70℃, 40 mL of 50% mass fraction of hydrogen peroxide is added dropwise, and the reaction is carried out for 8 h, after the reaction is completed, the reaction solution is washed with sodium carbonate solution and deionized water in sequence, the solvent is removed by rotary evaporation, and drying is carried out in a 50℃ vacuum drying box for 10 h to prepare the polyethylene resin containing epoxy group;

[0038] Step SS3: preparing the azidation polyethylene resin, the preparation mechanism is that the polyethylene resin containing epoxy group and sodium azide are used as raw materials, and the azidation polyethylene resin is prepared through the epoxy ring-opening azidation reaction, and the specific experimental steps are as follows: 20 g of polyethylene resin containing epoxy group and 100 mL of toluene are added into a 250 mL round-bottom flask, the temperature is raised to 80℃, stirring is performed until dissolution, 20 mL of deionized water solution containing 1.2 g of sodium azide and 0.1 g of ammonium chloride is added, mechanical stirring is uniformly performed, the reaction is carried out at 50℃ for 48 h, after the reaction is completed, the solvent is removed by rotary evaporation, washing is performed, and drying is carried out in a vacuum drying box at 50℃ for 10 h to prepare the azidation polyethylene resin.

[0039] Example three:

[0040] Preparation of PA6 / PET / LLDPE composite film I, which comprises the following raw materials in parts by weight:

[0041] 80 parts of acetylenyl PA6 / PET composite resin;

[0042] 20 parts of azidation polyethylene resin;

[0043] 4.6 parts of cuprous bromide;

[0044] 5.6 parts of N,N,N',N'',N''-pentamethyldivinyltriamine;

[0045] 60 parts of N,N-dimethylformamide;

[0046] The preparation method of the PA6 / PET / LLDPE composite film I comprises the following steps: adding the acetylenic PA6 / PET composite resin and the azidized polyethylene resin into N,N-dimethylformamide, uniformly dispersing by ultrasonic, adding cuprous bromide and N,N,N',N'',N''-pentamethyldivinyltriamine, uniformly mixing, performing the freeze-vacuum-thaw cycle three times, sealing under vacuum, and reacting at 60℃ for 2h; after the reaction is completed, cooling to room temperature, filtering, and vacuum drying to obtain the PA6 / PET / LLDPE composite resin.

[0047] The PA6 / PET / LLDPE composite resin is added into an extruder to be blow molded, wherein the process parameters of the extruder are as follows: the barrel three-zone temperature is 220℃, 250℃ and 250℃, the die temperature is 240℃, and the screw rotation speed is 30r / min, so as to obtain the PA6 / PET / LLDPE composite film I with a thickness of 20μm.

[0048] Example four:

[0049] The PA6 / PET / LLDPE composite film II comprises the following raw materials in parts by weight: 85 parts of acetylenic PA6 / PET composite resin; and 15 parts of azidized polyethylene resin.

[0050] The preparation process of the PA6 / PET / LLDPE composite film II is different from the preparation process of the PA6 / PET / LLDPE composite film I only in that the raw material formula of the PA6 / PET / LLDPE composite film II is used to replace the raw material formula of the PA6 / PET / LLDPE composite film I.

[0051] Example five:

[0052] The PA6 / PET / LLDPE composite film III comprises the following raw materials in parts by weight: 75 parts of acetylenic PA6 / PET composite resin; and 25 parts of azidized polyethylene resin.

[0053] The preparation process of the PA6 / PET / LLDPE composite film III is different from the preparation process of the PA6 / PET / LLDPE composite film I only in that the raw material formula of the PA6 / PET / LLDPE composite film III is used to replace the raw material formula of the PA6 / PET / LLDPE composite film I.

[0054] Comparative example:

[0055] The PA6 / PET composite film comprises the following raw materials in parts by weight: 50 parts of PA6 resin (model F136 / NA99001 / 4229D) and 50 parts of PET resin (brand 70G43L).

[0056] The difference between the preparation process of the PA6 / PET composite film and the preparation process of the PA6 / PET / LLDPE composite film I is only that the raw material formula of the PA6 / PET composite film is used to replace the raw material formula of the PA6 / PET / LLDPE composite film I.

[0057] Performance test:

[0058] I. Tensile strength and elongation at break: The tensile strength and elongation at break of the PA6 / PET / LLDPE composite film are tested according to GB / T 1040.3-2006 "Determination of the tensile properties of plastics - Part 3: test conditions for films and sheets", the length of the PA6 / PET / LLDPE composite film sample is 200mm, the width is 20mm, and the tensile speed is 200mm / min;

[0059] II. Puncture resistance: The puncture resistance of the PA6 / PET / LLDPE composite film is tested according to GB / T 37841-2019 "Test method for puncture resistance of plastic films and sheets", the size of the PA6 / PET / LLDPE composite film sample is 100mm*100mm, and the puncture speed is 50mm / min;

[0060] The above test results are shown in Table 1 below;

[0061] Table 1 Performance test results of PA6 / PET / LLDPE composite film

[0062]

[0063] From the experimental results in Table 1, it can be seen that:

[0064] The PA6 / PET / LLDPE composite film prepared by the present application has significantly improved toughness while its mechanical properties (tensile strength and puncture resistance) do not significantly decrease.

Claims

1. A high-performance composite film for drone battery packaging, characterized in that, The method for preparing the high-performance composite film includes the following steps: Step 1: Under the action of an initiator, LLDPE resin is melt-grafted and modified using tetramethyltetravinylcyclotetrasiloxane, and the alkenyl functional groups in LLDPE resin are oxidized into epoxy functional groups. Finally, a ring-opening reaction is carried out with sodium azide to obtain azide polyethylene resin. Step 2: Under the action of cuprous halide, the alkynyl functional groups in the alkynylated PA6 / PET composite resin undergo a click reaction with the azide groups in the azidolated polyethylene resin, and the LLDPE resin is covalently grafted onto the PA6 / PET composite resin. Finally, the PA6 / PET / LLDPE composite film is obtained by blow molding. Step 3: Composite the PA6 / PET / LLDPE composite film with the adhesive layer, barrier layer and inner layer to obtain a high-performance composite film.

2. The high-performance composite film for drone battery packaging according to claim 1, characterized in that, The preparation method of the acetylated PA6 / PET composite resin includes the following steps: In-situ compatibilization of PA6 resin and PET resin was carried out using epoxy compatibilizer, followed by chain extension reaction, to prepare hydroxyl-functionalized PA6 / PET composite masterbatch. Under the action of an alkaline catalyst, hydroxyl-functionalized PA6 / PET composite masterbatch undergoes a substitution reaction with 3-bromopropyne to obtain alkynylated PA6 / PET composite resin.

3. The high-performance composite film for drone battery packaging according to claim 2, characterized in that, The mass ratio of PA6 resin to PET resin in the hydroxyl-functionalized PA6 / PET composite masterbatch is 8:1-3; the amount of epoxy compatibilizer is 5-10% of the total mass of PA6 resin and PET resin.

4. The high-performance composite film for drone battery packaging according to claim 2, characterized in that, The epoxy compatibilizer is one of ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, and 1,4-butanediol diglycidyl ether.

5. The high-performance composite film for drone battery packaging according to claim 2, characterized in that, The alkaline catalyst is one of potassium hydroxide and sodium hydroxide.

6. The high-performance composite film for drone battery packaging according to claim 1, characterized in that, The initiator is one of dicumyl peroxide and tert-butyl peroxide.

7. The high-performance composite film for drone battery packaging according to claim 1, characterized in that, The cuprous halide is one of cuprous bromide, cuprous chloride, and cuprous iodide.

8. The high-performance composite film for drone battery packaging according to claim 1, characterized in that, The process parameters of the extruder used in the blow molding process are as follows: the temperature of the three zones of the barrel is 210-230℃, 240-260℃, and 240-260℃; the temperature of the die head is 230-250℃; and the screw speed is 25-35 r / min.

9. The high-performance composite film for drone battery packaging according to claim 1, characterized in that, The mass ratio of alkynylated PA6 / PET composite resin to azidolated polyethylene resin in the PA6 / PET / LLDPE composite film is 75-85:15-25.

10. The high-performance composite film for drone battery packaging according to any one of claims 1-9, characterized in that, The thickness of the PA6 / PET / LLDPE composite film is 10-25 μm.

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