PPE / PA alloy material for upper cover of power battery as well as preparation method and application of PPE / PA alloy material

Abstract

The invention belongs to the field of high polymer materials, and discloses a PPE / PA alloy material for an upper cover of a power battery as well as a preparation method and application of the PPE / PA alloy material. 5-35% of polyamide resin; 10-40% of a reinforcing body; 0.01 to 10% of a compatilizer; 0.01 to 10% of a flame retardant; 0-2% of a processing aid; and 0-1% of color master batch. The PPE / PA alloy material prepared by the invention has excellent mechanical properties, processability and flame retardant property, can be used as a first material of the upper cover of the power battery for replacing steel with plastic, and has important significance on light weight of the power battery and a new energy automobile.

Description

Technical Field

[0001] The present invention relates to the field of polymer materials, and in particular to a PPE / PA alloy material for a power battery upper cover, and a preparation method and application thereof. Background Art

[0002] The power battery system of new energy vehicles can be called the "heart" of new energy vehicles. The direct function of the power battery is to provide a power source for electric vehicles, which determines the cruising range of new energy vehicles. The cruising range determines the scope of use and mileage of new energy vehicles, and is a key factor in determining the market competitiveness of new energy vehicles. With the development of new energy vehicle technology, the market competitiveness of new energy vehicles has been gradually improved, but improving the cruising range is still one of the biggest challenges that new energy vehicles will face in the future. There are three main ways to improve the cruising range: improving battery performance, increasing battery capacity and lightweighting. Among them, lightweighting is the most feasible, economical and fastest method. The cost of power batteries accounts for 90% of the cost of the three electrics and 40% of the weight of the entire vehicle. The lightweighting of power batteries is an important direction for lightweighting new energy vehicles.

[0003] The upper cover of the power battery pack is an important component to protect the battery. It needs to have good high temperature resistance, corrosion resistance, high strength and lightweight properties. Commonly used upper cover materials are aluminum alloy and steel alloy. The "plastic instead of steel" upper cover of the battery pack can achieve a weight reduction of more than 40% of the parts, which is an important technical path for the research of lightweight power batteries. Polyphenylene ether (PPE) has excellent heat resistance, electrical insulation, mechanical properties, chemical stability, corrosion resistance, dimensional stability, self-extinguishing ability and low water absorption, but polyphenylene ether has poor fluidity, stress cracking, and poor fatigue resistance. Polyamide (PA) material has excellent mechanical properties, outstanding corrosion resistance, oil resistance, heat resistance, high modulus, fatigue resistance, creep resistance and processability. PPE and PA alloy materials can significantly improve its heat resistance, flame retardancy and fire resistance test performance.

[0004] Chinese patent CN111961342A discloses a method for preparing flame-retardant high-toughness nylon 66 / polyphenylene ether (PA66 / PPO) plastic alloy. The method is as follows: maleic anhydride (MAH) and high-impact polystyrene (HIPS) are melted and mixed together, and extruded into granules; then the granules are placed in a gamma-ray radiation field for irradiation, and the irradiated granules are mixed with PA66, PPO, flame retardants and other additives; finally, the above mixture is extruded and granulated on an extruder to obtain a flame-retardant high-toughness PA66 / PPO plastic alloy. Chinese patent CN105062035A relates to a low-temperature resistant, high CTI, high heat deformation halogen-free flame-retardant PPE and its preparation method. The impact performance of the PPE material is improved by the combined action of the toughening agent and silicone oil, and the CTI value of the PPE is improved by the hydrophobicity and non-polarity of PTFE. Chinese patent CN111154257A relates to an ultra-low water absorption PA66 / PPO composition and its preparation method. By introducing fluorinated silicone rubber on the PA matrix to prepare a water-absorbing modified masterbatch, the water absorption of PA66 is greatly reduced. At the same time, the anti-fouling and surface tactile lubricity of the material are improved to a certain extent. Therefore, it can be used in automobiles, home appliances and other appearance parts with high requirements for water absorption, anti-fouling and tactile feel. The currently disclosed patents have made certain studies on the modification technology of PPE mechanical properties, flame retardant properties, etc., but there are few studies on the technology of using PPE / PA alloy materials to replace steel with plastic, especially the research on the development of PPE / PA alloy materials that meet the working conditions of the battery cover of new energy vehicles. The development of materials for the battery cover of new energy vehicles is of great significance to the realization of lightweight power batteries and the improvement of the driving range and acceleration of new energy vehicles per 100 kilometers. Summary of the invention

[0005] The present invention provides a PPE / PA alloy material for a power battery upper cover, a preparation method and an application thereof. The PPE / PA alloy material is prepared by formula design, and the PPE / PA alloy material prepared by the method can be applied to the performance requirements of the material under the use conditions of the power battery upper cover of new energy vehicles.

[0006] The present invention is achieved through the following technical solutions: A PPE / PA alloy material for a power battery cover, comprising the following raw materials in percentage by weight: Functionalized MPPE resin 2-84.98%; Polyamide resin 5-35%; Enhancement 10-40%; Compatibilizer 0.01-10%; Flame retardant 0.01-10%; Processing aids 0-2%; Masterbatch 0-1%.

[0007] The functionalized MPPE resin is obtained by functionalizing and modifying the PPE resin. The weight average molecular weight of the PPE resin is 20,000-60,000, and the melt flow rate (test conditions: 280°C, 5kg) is 0.5-30g / 10min. The functionalization modification of PPE is prepared in two steps: first, the carboxyl modified PPE resin is prepared by reacting butyl lithium and carbon dioxide in anhydrous toluene solvent; secondly, the carboxyl modified PPE resin is acylated with a cyclophosphazene derivative with an amino terminal, so that the cyclophosphazene derivative functionalizes the PPE. The reaction rate of the terminal hydroxyl group of the functionalized MPPE resin is greater than 90%, and the reaction rate of the terminal carboxyl group is greater than 80%. The general structural formula is as follows:

[0008] The polyamide resin can be one or more of PA6, PA56, PA66, PA6 / 66, PA66 / 6, PA66 / 6T, PA612, PA1010, PA12, PA1012, PA11, PA510, PA46, PA4T, PA5T / X, PA6T / X, PA9T, PA10T, PA10T / X, PA12T, PA12T / X, etc., with a melting point (Tm) of 180-320°C, a relative viscosity of 1.8-3.0 (test standard: FZT51004-2011), and a terminal amino content of ≥60mmol / kg.

[0009] The reinforcement can be one or more of glass fiber, basalt fiber, etc. The preferred reinforcement of the present invention is glass fiber, alkali content <0.8%, volume density 0.6-0.8g / cm3, single fiber diameter: 7-13μm, short cut length: 2-5mm, moisture content ≤0.05%, glass fiber surface treated with sizing agent, sizing agent mass fraction >0.3%.

[0010] The compatibilizer can be one or more of PPO-g-MAH, SEBS-g-MAH, SBS-g-MAH, etc. The preferred compatibilizer of the present invention is PPO-g-MAH.

[0011] The flame retardant is a new type of phosphorus flame retardant. The flame retardant has balanced the three functions of free radical capture, oxygen isolation, and carbon formation through the design of the molecular structure, thereby improving the flame retardant efficiency. The phosphorus content is 15-19% (17.9%), the aluminum content is 3.0-6.0% (5.2%); the density is 1.32-1.38g / cm3; the particle size (D50) is 10-35μm; the structural formula of the flame retardant is as follows: .

[0012] The processing aid is one or more of a dendritic structure additive containing a special functional group, saponified calcium montanate, oxidized polyethylene wax, calcium stearate, phenyl silicone, etc. In the present invention, phenyl silicone is preferred.

[0013] The masterbatch can be one or more of carbon black, zinc sulfide, iron oxide, etc. according to the color requirements, with a toner content of 20-99%, and a carrier of PA6, PA66, PPO or lubricant.

[0014] The method for preparing the PPE / PA alloy material for the power battery upper cover comprises the following steps: (1) The moisture content of polyamide resin is not higher than 2000ppm; (2) Weigh various dried raw materials according to the formula ratio; mix the functionalized MPPE resin, polyamide resin, compatibilizer, flame retardant, processing aid, and masterbatch evenly with a high-speed mixer and set aside; weigh the reinforcement according to the ratio and set aside; (3) The resin and additive mixture is added through the main feed port of a twin-screw extruder, and the filler is added through the side feed port of the twin-screw extruder. After melt extrusion, granulation, drying and other processes, the PPE / PA alloy material is obtained.

[0015] The above-mentioned PPE / PA alloy material can be applied to the upper cover of power batteries of new energy vehicles.

[0016] The advantage of the present invention is that the PPE / PA alloy material prepared by formula design meets the performance requirements of "plastic instead of steel" as the material for the upper cover of the power battery of new energy vehicles. The functionalized MPPE resin is selected in the formula design to increase the flame retardant performance of the PPE body and the compatibility of PPE with polyamide resin and reinforcement. According to the principle of molecular structure design, the flame retardant selected in the formula design has good compatibility with polyamide and PPE resin, and can play a good synergistic role with the functional groups of PPE resin, balancing the three effects of the flame retardant in free radical capture, oxygen isolation, and carbon formation, thereby improving the flame retardant efficiency. It is achieved that the PPE / PA alloy material meets the mechanical properties, processing properties and flame retardant performance requirements of the upper cover of the power battery for the material.

[0017] The beneficial effects of the present invention are: Functionalized MPPE resin is introduced in the formula design, and the functional modification of PPE is prepared in two steps: first, carboxyl-modified MPPE resin is prepared by reacting butyl lithium and carbon dioxide in anhydrous toluene solvent; secondly, the carboxyl-modified PPE resin is acylated with a cyclophosphazene derivative with a terminal amino group, so that the cyclophosphazene derivative functionalizes PPE to give the MPPE resin body flame retardant properties. The functionalized MPPE resin has polar amino and carboxyl groups, which increase the polarity of the resin compared to the PPE resin, thereby increasing the compatibility of MPPE with polyamide resin, reinforcement and flame retardant, and increasing the mechanical properties of the PPE / PA alloy material.

[0018] A new type of flame retardant was introduced in the formula design. According to the characteristics of the combustion process of polyamide and PPE resin and the principle of molecular structure design, an organic phosphorus flame retardant was selected. The molecular structure of the flame retardant contains P element, Al element and benzene ring structure, which balances the three functions of the flame retardant in free radical capture, oxygen isolation and carbon formation, thereby improving the flame retardant efficiency.

[0019] 3) The phosphazene groups of the functionalized MPPE resin in the formula design of the present invention can play a synergistic role with the flame retardant, thereby improving the flame retardant efficiency, thereby achieving excellent flame retardant effect with a relatively small amount of flame retardant added, and the comprehensive performance of the prepared PPE / PA alloy material is greatly improved.

[0020] 4) The PPE / PA alloy material prepared by the present invention can achieve excellent flame retardant effect with a small amount of flame retardant added, and the material has excellent mechanical properties and processing properties, which meets the performance requirements of the material for the power battery cover of new energy vehicles, and realizes the "plastic instead of steel" of the power battery cover, which is of great significance for the lightweight of power batteries and new energy vehicles.

[0021] The above beneficial effects achieve excellent mechanical properties, processing properties and flame retardant properties of the PPE / PA alloy material. DETAILED DESCRIPTION

[0022] In order to make the technical problems, technical solutions and intentions to be solved by the present invention clearer, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0023] The embodiments and comparative examples of the present invention use the following materials, but are not limited to the following materials: Polyamide resin PA66, brand EPR27, produced by Shenma Engineering Plastics Co., Ltd.; Functionalized MPPE resin, homemade; PPE, brand LXN040, produced by Nantong Xingchen Synthetic Materials Co., Ltd.; Glass fiber, brand ECS301HP-3, produced by Chongqing International Composite Materials Co., Ltd.; Compatibilizer PPO-g-MAH, brand name GPM450C, produced by Ningbo Nengzhiguang New Materials Co., Ltd.; Modified flame retardant, homemade; Flame retardant ADP, brand OP1230, produced by Clariant; The flame retardant phosphazene, brand name SPB100, is produced by Otsuka Chemical.

[0024] Flame retardant BDP, brand name WSFR-BDP, produced by Zhejiang Wansheng Co., Ltd.; Processing aid, brand name LYSI-100E, produced by Chengdu Silike Technology Co., Ltd.; Masterbatch, brand TA5101, is produced by Jiangsu Haiyan New Materials Co., Ltd.

[0025] In the embodiment of the present invention, The preparation method of the functionalized MPPE resin is as follows: first, a carboxyl-modified PPE resin is prepared by reacting butyl lithium and carbon dioxide in anhydrous toluene solvent; secondly, the carboxyl-modified PPE resin is subjected to an acylation reaction with a cyclophosphazene derivative with a terminal amino group, so that the cyclophosphazene derivative functionalizes the PPE, and the reaction rate of the terminal hydroxyl group of the functionalized MPPE resin is greater than 90%, and the reaction rate of the terminal carboxyl group is greater than 80%.

[0026] The flame retardant is prepared according to the following preparation method: 1) bisphenol A and phosphorus oxychloride react at 120°C for 3.5 hours to perform an acyl chlorination reaction; 2) the reaction product of step 1) is dripped into a four-necked bottle filled with a phosphorus-containing compound, the temperature is maintained at 80°C to 150°C and protected with nitrogen; 3) a reflux device is always provided in step 2), and after the dripping is completed, the reflux is continued for 10 to 48 hours, and separation and purification are performed to obtain the flame retardant.

[0027] Preparation methods of Examples 1-6 and Comparative Examples 1-6: Preparation method of PPE / PA alloy material (1) The moisture content of polyamide resin is not higher than 2000ppm; (2) Weigh various dried raw materials according to the formula ratio; mix the functionalized MPPE resin, polyamide resin, compatibilizer, flame retardant, processing aid, and masterbatch evenly with a high-speed mixer and set aside; weigh the reinforcement according to the ratio and set aside; (3) The resin and additive mixture is added through the main feed port of a twin-screw extruder, and the filler is added through the side feed port of the twin-screw extruder. After melt extrusion, granulation, drying and other processes, the PPE / PA alloy material is obtained.

[0028] Preparation of PPE / PA alloy material test specimens: The above materials were dried in a forced air drying oven at 120°C for 4 hours and then injection molded into standard specimens at an injection molding temperature of 280-330°C. The prepared mechanical properties specimens were conditioned in a standard laboratory environment (23°C, 50% RH) for 24 hours before testing.

[0029] Test methods for each performance index: Tensile properties: According to ISO 527 method, sample size: 170mm×10mm×4mm, test speed 5mm / min.

[0030] Bending properties: According to ISO 178 method, sample size: 80mm×10mm×4mm, test speed 2mm / min.

[0031] Notched impact performance: According to ISO 179 method, sample size: 80mm×10mm×4mm.

[0032] Heat deformation temperature: according to ISO 75 method, sample size: 80mm×10mm×4mm, test condition: 1.8MPa.

[0033] Flame retardant performance: According to UL94 method, sample size: 127mm×12.7mm×1.6mm.

[0034] Table 1: Composition and properties of PPE / PA alloy materials in Examples 1-6 and Comparative Examples 1-6

[0035] It can be seen from the results of the embodiments and comparative examples in Table 1 that the introduction of new flame retardants and functionalized MPPE in the formula design can improve the flame retardant properties and mechanical properties of PPE / PA alloy materials. Through Examples 1-6, in different nylon content and glass fiber content material grades, the PPE / PA material can achieve stable V0 flame retardant properties and obtain excellent mechanical properties with a small amount of flame retardant added; by comparing Examples 1-2 and Comparative Examples 1-3, it can be seen that with the same amount of flame retardant added, the flame retardant involved in the present invention can achieve more excellent flame retardant properties, because the flame retardant P, Al and benzene ring content of the present invention balance the flame retardant in free radical capture, oxygen isolation, carbon formation and other three aspects, thereby improving the flame retardant efficiency. It can be seen from the comparison of Examples 1-2 and Comparative Examples 4-6 that the functionalized MPPE can achieve more beneficial flame retardant and mechanical properties than conventional PPE resins, because the functionalized MPPE resins have polar amino and carboxyl groups, which increase the polarity of the resin compared to the PPE resin, thereby increasing the compatibility of MPPE with polyamide resins, reinforcements and flame retardants, and increasing the mechanical properties of the PPE / PA alloy material. The PPE / PA alloy material prepared by the present invention has excellent mechanical properties, processing properties and flame retardant properties, and can be used as the preferred material for "plastics instead of steel" for power batteries, which is of great significance to the lightweighting of power batteries and new energy vehicles.

Claims

1. A PPE / PA alloy material for a power battery cover, characterized in that: The raw material composition is as follows by weight percentage: Functionalized MPPE resin 2-84.98%; Polyamide resin 5-35%; Enhancement 10-40%; Compatibilizer 0.01-10%; Flame retardant 0.01-10%; Processing aids 0-2%; Masterbatch 0-1%; The functionalized MPPE resin is obtained by functionally modifying a PPE resin, wherein the weight average molecular weight of the PPE resin is 20,000-60,000, and the melt flow rate is 0.5-30 g / 10 min under the test conditions of 280° C. and 5 kg; the functionalized modification of PPE is prepared in two steps: firstly, a carboxyl-modified PPE resin is prepared by reacting butyl lithium and carbon dioxide in anhydrous toluene solvent; secondly, the carboxyl-modified PPE resin is subjected to an acylation reaction with a cyclophosphazene derivative with a terminal amino group, so that the cyclophosphazene derivative functionalizes the PPE, and the reaction rate of the terminal hydroxyl group of the functionalized MPPE resin is greater than 80%, and the reaction rate of the terminal carboxyl group is greater than 60%; the general structural formula is as follows: ； The flame retardant is a phosphorus-based flame retardant. The molecular structure is designed to balance the flame retardant's effects on free radical capture, oxygen isolation, and carbonization, thereby improving the flame retardant efficiency. By mass percentage, the phosphorus content is 16-20%, the aluminum content is 4.0-7.0%; the density is 1.32-1.38 g / cm 3 ; Particle size (D50) 10-35μm; The structural formula of the flame retardant is as follows: 。 2. The PPE / PA alloy material for a power battery upper cover according to claim 1, characterized in that: The polyamide resin is one or more of PA6, PA56, PA66, PA6 / 66, PA66 / 6, PA66 / 6T, PA612, PA1010, PA12, PA1012, PA11, PA510, PA46, PA4T, PA5T / X, PA6T / X, PA9T, PA10T, PA10T / X, PA12T, and PA12T / X; the melting point (Tm) is 180-320° C., the relative viscosity is 1.8-3.0, and the terminal amino group content is ≥60 mmol / kg.

3. The PPE / PA alloy material for a power battery upper cover according to claim 1, characterized in that: The reinforcement is selected from one or more of glass fiber and basalt fiber.

4. The PPE / PA alloy material for a power battery upper cover according to claim 3, characterized in that: The reinforcement is glass fiber, the alkali content is less than 0.8% by mass, and the volume density is 0.6-0.8g / cm 3 , monofilament fiber diameter: 7-13μm, short cut length: 2-5mm, moisture content by mass percentage ≤0.05%, glass fiber surface treated with sizing agent, sizing agent mass fraction>0.3%.

5. The PPE / PA alloy material for a power battery upper cover according to claim 1, characterized in that: The compatibilizer is one or more of PPO-g-MAH, SEBS-g-MAH and SBS-g-MAH.

6. The PPE / PA alloy material for a power battery upper cover according to claim 5, characterized in that: The compatibilizer is PPO-g-MAH.

7. The PPE / PA alloy material for a power battery upper cover according to claim 1, characterized in that: The processing aid is one or more of saponified calcium montanate, oxidized polyethylene wax, calcium stearate and phenyl silicone.

8. The PPE / PA alloy material for a power battery upper cover according to claim 7, characterized in that: The processing aid is selected from phenyl silicone.

9. The PPE / PA alloy material for a power battery upper cover according to claim 1, characterized in that: The masterbatch comprises a toner and a carrier. The toner is selected from one or more of carbon black, zinc sulfide and iron oxide, and the content thereof is 20-99% by weight. The carrier is a masterbatch of PA6, PA66 and PPO.

10. The method for preparing the PPE / PA alloy material for the power battery upper cover according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) The moisture content of polyamide resin is not higher than 2000ppm; (2) Weigh various dried raw materials according to the formula ratio; mix the functionalized MPPE resin, polyamide resin, compatibilizer, flame retardant, processing aid, and masterbatch evenly with a high-speed mixer and set aside; weigh the reinforcement according to the ratio and set aside; (3) The functionalized MPPE resin, polyamide resin, compatibilizer, flame retardant, processing aid, and masterbatch mixed raw materials are added through the main feeding port of the twin-screw extruder, and the reinforcement is added from the side feeding port of the twin-screw extruder. After the melt extrusion, granulation, and drying processes, the PPE / PA alloy material is obtained.

11. Application of the PPE / PA alloy material for power battery top cover according to any one of claims 1 to 9.

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