A composite resin material for new energy battery packs and a preparation method thereof

Abstract

The application belongs to the field of polymer alloy materials, and relates to a composite resin material for a new energy battery pack and a preparation method thereof.The composite resin material for the new energy battery pack comprises, in terms of weight fractions, 40-60 parts of polyphenyl ether PPE, 20-40 parts of polystyrene PS, 6-10 parts of a composite flame retardant, 3-5 parts of a compatibilizer, and 0.2-0.8 parts of an antioxidant.The composite flame retardant is a compound of aluminum diethyl phosphinate ADP and melamine polyphosphate MPP, the weight ratio of the aluminum diethyl phosphinate ADP to the melamine polyphosphate MPP is (5:3) to (3:1), the polyphenyl ether PPE is first subjected to pre-dispersion treatment with part of the compatibilizer, and then is subjected to melt blending with a mixture containing the remaining compatibilizer, the polystyrene PS, the composite flame retardant and the antioxidant.The composite resin material is efficient in environmental protection and flame retardation, excellent in mechanical properties, improved in heat resistance, good in processing performance, and simple and controllable in process.

Description

Technical Field

[0001] This invention relates to the field of polymer alloy materials technology, and in particular to a composite resin material for new energy battery packs and its preparation method. Background Technology

[0002] With the rapid development of the new energy vehicle industry, the requirements for the safety, lightweighting, and reliability of power battery packs are becoming increasingly stringent. The battery pack casing and internal structural components not only need to possess good mechanical strength, dimensional stability, and heat resistance, but must also meet stringent flame-retardant safety standards to prevent battery thermal runaway and subsequent fires.

[0003] Polyphenylene oxide (PPE) possesses excellent high-temperature resistance, electrical insulation, dimensional stability, and low moisture absorption, but its melt flowability is poor, processing is difficult, and its cost is high. Polystyrene (PS), especially high-impact polystyrene (HIPS), has excellent processing flowability, high gloss, and low cost, but its heat resistance is poor, impact strength is limited, and it is flammable. Blending PPE and PS to prepare PPE / PS alloys can effectively combine the advantages of both, and has broad application prospects in electronics, automotive parts, and other fields.

[0004] However, unmodified PPE / PS alloys typically have a limiting oxygen index (LOI) below 20% and a vertical flammability rating of only UL94 HB, classifying them as flammable materials. This fails to meet the stringent flame retardancy requirements of materials used in new energy battery packs and other fields (typically requiring UL94 V-0 rating and LOI ≥ 28%). Currently, the common method for flame-retardant modification of PPE / PS alloys is the addition of flame retardants, primarily including: Brominated flame retardants: They have high flame retardant efficiency, but they easily produce toxic and corrosive hydrogen bromide gas and dioxins when burning, causing significant environmental pollution and being subject to increasingly stringent environmental regulations (such as RoHS and REACH).

[0005] Single phosphorus-based flame retardants (such as phosphate esters, phosphinates, etc.) are relatively environmentally friendly, but a high addition amount (≥12 wt%) is usually required to achieve the UL94 V-0 rating. This will seriously deteriorate the mechanical properties of the alloy (such as impact strength, tensile strength) and heat distortion temperature (HDT), and may also cause flame retardant migration and precipitation, affecting the long-term stability and surface properties of the material.

[0006] Inorganic flame retardants (such as aluminum hydroxide and magnesium hydroxide) are environmentally friendly and non-toxic, but the amount added is extremely large (often exceeding 50%), which seriously impairs the processing fluidity and mechanical properties of the material.

[0007] Furthermore, PPE and PS generally have poor compatibility, and simple mechanical blending easily leads to phase separation, affecting the overall performance of the alloy. Therefore, achieving efficient flame retardancy (V-0 rating), excellent mechanical properties, good processing fluidity, and long-term stability in PPE / PS alloys with relatively low flame retardant addition is currently the main technical challenge in this field. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention provides a composite resin material for new energy battery packs, employing the technical solution described below. By weight, it comprises the following raw materials: 40-60 parts polyphenylene ether (PPE); 20-40 parts polystyrene (PS); 6-10 parts composite flame retardant; 3-5 parts compatibilizer; and 0.2-0.8 parts antioxidant. The composite flame retardant is a compound of aluminum diethyl phosphonate (ADP) and melamine polyphosphate (MPP), with a weight ratio of ADP to MPP of (5:3) to (3:1). The PPE is first pre-dispersed with a portion of the compatibilizer, and then melt-blended with a mixture containing the remaining compatibilizer, polystyrene (PS), composite flame retardant, and antioxidant.

[0009] Preferably, the polyphenylene ether (PPE) is a pre-dispersed polyphenylene ether used to pre-melt mix with a portion of the compatibilizer to form a polyphenylene ether pre-dispersion.

[0010] Preferably, the polystyrene PS is high-impact polystyrene HIPS, and its melt flow rate is 5 to 15 g / 10 min at 220°C and 10 kg load.

[0011] Preferably, the compatibilizer is styrene-ethylene / butene-styrene block copolymer SEBS or styrene-butadiene-styrene block copolymer SBS.

[0012] Preferably, the antioxidant is a compound antioxidant, composed of a primary antioxidant and a secondary antioxidant in a weight ratio of (1-2):1; the primary antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] i.e., antioxidant 1010, and the secondary antioxidant is tris(2,4-di-tert-butylphenyl) phosphite i.e., antioxidant 168.

[0013] In order to solve the above-mentioned technical problems, on the other hand, the present invention also provides a method for preparing a composite resin material for a new energy battery pack. The method for preparing the above-mentioned composite resin material for a new energy battery pack includes the following steps: S1, premixing all polyphenylene ether (PPE) with 30%-50% compatibilizer by weight, and performing preliminary melt dispersion treatment to obtain a polyphenylene ether (PPE) predisperse. S2, polystyrene PS, composite flame retardant, residual compatibilizer, antioxidant and polyphenylene ether PPE predispersant obtained in step S1 are mixed at high speed to obtain the main premix; S3, the main premix is ​​added to a twin-screw extruder and melt-blended, extruded, cooled, and pelletized in a temperature range of 240-280℃ to obtain the composite resin material particles; wherein, the melt-blending process is carried out by controlling the screw speed and temperature distribution to apply alternating high-shear mixing and reverse conveying action to the material to promote uniform dispersion of each component.

[0014] Preferably, the preliminary melt dispersion treatment in step S1 is carried out in an internal mixer or a small single-screw extruder at a temperature of 260-280°C for 3-8 minutes.

[0015] Preferably, the high-speed mixing time in step S2 is 10-20 minutes.

[0016] Preferably, in step S3, the polyphenylene oxide (PPE) predispersant and the main premix containing polystyrene (PS) and a composite flame retardant are added at different stages in the twin-screw extruder so that the PPE predispersant merges with the main premix in the middle and later stages of melt blending.

[0017] Preferably, the screw speed of the twin-screw extruder in step S3 is 300-400 r / min.

[0018] Compared with the prior art, the present invention has the following main advantages: (1) By combining ADP and MPP, a synergistic flame retardant effect is formed. Only 6-10 parts of the addition amount are needed to make a 1.6mm sample achieve the UL94 V-0 rating during vertical burning, and the limiting oxygen index (LOI) can be increased to more than 30%. This flame retardant system does not contain halogens, has low smoke density and low toxicity during combustion, meets environmental protection requirements, and is a highly efficient and environmentally friendly flame retardant. (2) Under the combined action of low-addition composite flame retardant and compatibilizer SEBS, the mechanical properties of the material are maintained or even improved. The impact strength of the material of this invention can reach more than 20 kJ / m2, and the tensile strength can reach more than 60 MPa, which is significantly better than the comparative materials using a single flame retardant or a high-addition flame retardant, and the mechanical properties are excellent; (3) Compatibilizers improve the phase interface, and some components in the composite flame retardant (such as montmorillonite or ADP) also help to improve thermal stability, so that the heat distortion temperature (1.82 MPa) of the material can be increased by 15-30℃ compared with the system without compatibilizer or using a single flame retardant, thus improving heat resistance. (4) By controlling the viscosity of PPE, selecting HIPS with appropriate flowability and optimizing the process, the melt flow rate of the final alloy (280℃, 10kg) can be maintained above 8 g / 10min, which meets the injection molding requirements of complex structure battery pack shells and parts, and has good processing performance. (5: The preparation process can achieve stable and efficient industrial production using a conventional twin-screw extrusion production line, with low cost and simple and controllable process.) Attached Figure Description

[0019] To more clearly illustrate the solutions in this invention, the accompanying drawings used in the description of the embodiments of this invention will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a flowchart of the preparation method of the composite resin material for new energy battery packs according to the present invention. Detailed Implementation

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein in the specification is for the purpose of describing particular embodiments only and is not intended to limit the invention; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings are used to distinguish different objects and not to describe a particular order.

[0022] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0023] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0024] Raw material description: PPE: intrinsic viscosities of 0.35 dL / g, 0.40 dL / g, and 0.45 dL / g, respectively.

[0025] HIPS: Melt flow rates (220℃, 10kg) were 5 g / 10min, 10 g / 10min, and 15 g / 10min, respectively.

[0026] ADP: Aluminum diethylphosphonate, industrial grade.

[0027] MPP: Melamine polyphosphate, industrial grade.

[0028] BDP: Bisphenol A-bis(diphenyl phosphate), industrial grade (comparative to brominated phosphate flame retardants).

[0029] SEBS: Styrene-ethylene / butene-styrene block copolymer, grade G1651.

[0030] Antioxidant 1010: Pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]

[0031] Antioxidant 168: Tris(2,4-di-tert-butylphenyl) phosphite.

[0032] Montmorillonite: Organically modified montmorillonite (OMMT).

[0033] Performance testing standards: Limiting Oxygen Index (LOI): Tested according to GB / T 2406.2-2009.

[0034] Vertical burning (UL94): Test a 1.6 mm thick specimen according to ANSI / UL94-2013 standard.

[0035] Notched impact strength of simply supported beams: tested according to GB / T 1043.1-2008.

[0036] Tensile strength: Tested according to GB / T 1040.2-2006.

[0037] Melt flow rate (MFR): Tested according to GB / T 3682.1-2018, under the condition of 280℃ / 10kg.

[0038] Heat distortion temperature (HDT): Tested according to GB / T 1634.2-2019, with a load of 1.82 MPa.

[0039] Example 1 Raw material composition (by weight): Polyphenylene oxide (PPE): 60 parts, selected with an intrinsic viscosity of 0.35 dL / g to ensure processing fluidity; High-impact polystyrene (HIPS): 31.5 parts, with a melt flow rate (220℃, 10kg) of 10 g / 10min; Composite flame retardant: 8 parts, composed of aluminum diethylphosphinate (ADP) and melamine polyphosphate (MPP) in a weight ratio of 6:2; Compatibilizer: 4 parts, using styrene-ethylene / butene-styrene block copolymer (SEBS, grade G1651); Antioxidant: 0.5 parts, composed of primary antioxidant 1010 and secondary antioxidant 168 in a weight ratio of 0.3:0.2.

[0040] Figure 1 This is a flowchart illustrating the preparation method of the composite resin material for new energy battery packs according to the present invention. Figure 1 As shown, the preparation method includes: (1) Add all 60 parts of PPE and 1.2 parts (accounting for 30% of the total SEBS) of SEBS into a small internal mixer and melt mix at 270°C for 5 minutes to obtain PPE predispersed material. (2) Add 31.5 parts HIPS, 6 parts ADP, 2 parts MPP, the remaining 2.8 parts SEBS, 0.3 parts antioxidant 1010, 0.2 parts antioxidant 168 and the PPE predispersant obtained in step (1) into a high-speed mixer and mix at room temperature for 15 minutes to obtain a uniform main premix. (3) The main premix is ​​fed into a co-rotating parallel twin-screw extruder (screw length-to-diameter ratio L / D = 40:1) through the main feed port (located in the third zone). The extruder screw configuration includes three high-shear engagement block zones and two reverse conveying element zones. The polyphenylene oxide (PPE) predispersant is not added with the main premix, but is quantitatively added through the side feed port in the sixth zone (i.e., the middle and later section of melt blending, avoiding the high-shear zone at the front end) to achieve the convergence of the PPE predispersant and the main premix in the middle and later section of the extruder, avoiding premature strong shearing of PPE and resulting in degradation or uneven dispersion, while also helping to maintain melt strength and uniform distribution of flame retardant. The barrel temperature is set from the first zone to the die head as 240℃, 250℃, 260℃, 270℃, 275℃, 280℃, and 275℃, and the screw speed is set to 350 r / min. The molten material is extruded, water-cooled, traction-driven, and pelletized to obtain alloy particles. The resulting granules were dried at 100°C for 4 hours and then injection molded into standard test strips.

[0041] Performance test results: Flame retardant performance: Limiting oxygen index (LOI) is 34.0%; vertical burning test of 1.6mm thick sample reaches UL94 V-0 rating.

[0042] Mechanical properties: The notched impact strength of the simply supported beam is 20.1 kJ / m. 2 The tensile strength is 60.5 MPa.

[0043] Processing and heat resistance properties: melt flow rate (280℃, 10kg) is 12.0 g / 10min; heat distortion temperature (1.82MPa) is 136℃.

[0044] Example 2 Raw material composition (by weight): Polyphenylene oxide (PPE): 60 parts, using a grade with an intrinsic viscosity of 0.40 dL / g for better heat resistance; High-impact polystyrene (HIPS): 31.5 parts, with a melt flow rate (220℃, 10kg) of 15 g / 10min for better fluidity; Composite flame retardant: 8 parts, a mixture of ADP and MPP in a weight ratio of 6:2; Compatibilizer: 4 parts, SEBS (G1651); Antioxidant: 0.3 parts, a mixture of antioxidants 1010 and 168 in a weight ratio of 1:1.

[0045] Preparation methods include: (1) All 60 parts of PPE and 2 parts (accounting for 50% of the total SEBS) of SEBS were melt-dispersed in a small single-screw extruder (L / D=25:1). The temperature of each zone was set to 265-275℃ and the extrusion speed was 50 r / min. After extrusion, the PPE pre-dispersed material was obtained by water cooling and pelletizing. (2) Main premixing: 31.5 parts HIPS, 6 parts ADP, 2 parts MPP, the remaining 2 parts SEBS, 0.15 parts antioxidant 1010, 0.15 parts antioxidant 168 and the PPE predispersed particles obtained in step (1) are mixed at high speed for 15 minutes. (3) Melt blending and extrusion: The mixture is fed into a twin-screw extruder (L / D=40:1, screw configuration includes 3 high-shear zones and 2 reverse element zones) through the main feed port (third zone). The polyphenylene oxide (PPE) predispersant particles are not added with the main premix but are instead added through the side feed port in the fifth zone (i.e., the middle to later stage of melt blending). This ensures that the PPE predispersant is added to the main premix only after the material has partially melted and formed a continuous phase, thereby reducing thermomechanical damage to PPE and improving its interfacial compatibility with HIPS. The processing temperature range is 240-280℃, and the screw speed is 350 r / min. Subsequent steps are the same as in Example 1.

[0046] Performance test results: Flame retardant performance: Limiting oxygen index is 32.5%; vertical burning rating is UL94 V-0.

[0047] Mechanical properties: Impact strength is 22.0 kJ / m 2The tensile strength is 62.0 MPa.

[0048] Processing and heat resistance properties: melt flow rate is 9.0 g / 10 min; heat distortion temperature is 138℃.

[0049] Example 3 Raw material composition (by weight): Polyphenylene oxide (PPE): 50 parts, intrinsic viscosity 0.40 dL / g; High-impact polystyrene (HIPS): 33.8 parts, melt flow rate 10 g / 10min; Composite flame retardant: 6 parts, compounded from ADP and MPP in a weight ratio of 4.5:1.5 (i.e., 3:1); Compatibilizer: 4 parts, SEBS (G1651); Antioxidant: 0.4 parts, compounded from antioxidant 1010 and 168 in a weight ratio of 1:1.

[0050] Preparation methods include: (1) Pretreatment: Mix all 50 parts of PPE and 1.6 parts (40%) of SEBS in an internal mixer at 265°C for 4 minutes. (2) Main premixing: Mix 33.8 parts HIPS, 4.5 parts ADP, 1.5 parts MPP, 2.4 parts SEBS, 0.2 parts antioxidant 1010, 0.2 parts antioxidant 168 with PPE predispersant at high speed for 12 minutes. (3) Melt blending and extrusion: The main premix is ​​fed into a twin-screw extruder (L / D=40:1, specific screw configuration) through the main feed port. The polyphenylene oxide (PPE) predispersant is not added through the main feed port, but through the sixth zone side feed port in the middle and later stages of melt blending. This allows the PPE predispersant to merge with the molten main premix at the rear of the extruder, preventing it from entering the high-shear zone prematurely, thereby optimizing the flame retardant distribution and improving impact strength and heat distortion temperature. The processing temperature is 250-270℃, and the screw speed is 380 r / min. Subsequent steps are the same as in Example 1.

[0051] Performance test results: Flame retardant performance: Limiting oxygen index is 31.0%; vertical burning rating is UL94 V-0.

[0052] Mechanical properties: Impact strength is 23.5 kJ / m 2 The tensile strength is 58.0 MPa.

[0053] Processing and heat resistance properties: The melt flow rate is relatively high, at 15.5 g / 10 min; the heat distortion temperature is 132℃.

[0054] Example 4 Raw material composition (by weight): Polyphenylene oxide (PPE): 50 parts, intrinsic viscosity 0.35 dL / g; High-impact polystyrene (HIPS): 32.5 parts, melt flow rate 10 g / 10min; Composite flame retardant: 8 parts, composed of ADP and MPP in a weight ratio of 5:3; Compatibilizer: 4 parts, SEBS (G1651); Antioxidant: 0.5 parts, composed of antioxidant 1010 and 168 in a weight ratio of 1:1.

[0055] Preparation methods include: (1) Pretreatment: Mix all 50 parts of PPE and 1.2 parts (30%) of SEBS in an internal mixer at 270°C for 6 minutes. (2) Main premixing: Mix 32.5 parts HIPS, 5 parts ADP, 3 parts MPP, 2.8 parts SEBS, 0.25 parts antioxidant 1010, 0.25 parts antioxidant 168 with PPE predispersant at high speed for 15 minutes.

[0056] (3) Melt blending and extrusion: Process parameters: processing temperature 245-275℃, screw speed 320 r / min, twin-screw extruder length-to-diameter ratio 40:1, specific screw configuration, main-side feeding method. The polyphenylene oxide (PPE) pre-dispersion is added through the side feed port in the sixth zone (middle-rear section) of the extruder, where it merges with the main premix added through the main feed port in a molten state. This delays the introduction of the PPE phase, reducing its residence time in the early high-shear zone, which helps maintain molecular weight and promotes uniform blending with HIPS. Subsequent steps are the same as in Example 1.

[0057] Performance test results: Flame retardant performance: Limiting oxygen index is 33.2%; vertical burning rating is UL94 V-0.

[0058] Mechanical properties: Impact strength is 21.8 kJ / m 2 The tensile strength is 61.5 MPa.

[0059] Processing and heat resistance properties: melt flow rate is 10.5 g / 10 min; heat distortion temperature is 134℃.

[0060] Example 5 Raw material composition (by weight): Polyphenylene oxide (PPE): 45 parts, selected from grades with higher intrinsic viscosity (0.45 dL / g) to improve heat resistance; High-impact polystyrene (HIPS): 38.5 parts, melt flow rate of 10 g / 10 min; Composite flame retardant: 10 parts, compounded from ADP and MPP in a weight ratio of 7:3; Compatibilizer: 4 parts, SEBS (G1651); Antioxidant: 0.6 parts, compounded from antioxidants 1010 and 168 in a weight ratio of 1:1.

[0061] Preparation methods include: (1) Mix all 45 parts of PPE with 2 parts (50%) of SEBS in a mixer at 275°C for 7 minutes. (2) Mix 38.5 parts HIPS, 7 parts ADP, 3 parts MPP, 2 parts SEBS, 0.3 parts antioxidant 1010, 0.3 parts antioxidant 168 with PPE predispersant at high speed for 18 minutes. (3) Process parameter settings: processing temperature 240-280℃, screw speed 300 r / min, twin-screw extruder length-to-diameter ratio 40:1, specific screw configuration, main-side feeding method. Consistent with the previous embodiment, the polyphenylene oxide (PPE) pre-dispersion is not added from the main feed port along with the main premix, but is quantitatively added through the side feed port in the fifth or sixth zone of the extruder (i.e., the middle and later section of melt blending), so that it merges after the main premix has formed a melt flow, thereby achieving the effect of "staged blending", which significantly improves the compatibility of PPE and PS and the dispersion uniformity of flame retardant. Subsequent steps are the same as in Example 1.

[0062] Performance test results: Flame retardant performance: Limiting oxygen index is 35.5%; vertical burning rating is UL94 V-0.

[0063] Mechanical properties: Impact strength is 19.5 kJ / m 2 The tensile strength is 59.0 MPa.

[0064] Processing and heat resistance properties: melt flow rate is 8.5 g / 10min; heat distortion temperature is the highest in this series, reaching 140℃.

[0065] Examples 1-5 detail the composite resin materials of the present invention under different ratios and process parameters. The specific composition and preparation conditions are shown in Table 1, and the performance test results are shown in Table 2.

[0066] Table 1: Raw material composition (parts by weight) and process parameters for Examples 1-5 Preparation method: Taking Example 1 as an example, weigh each component according to the proportions in Table 1. Add all 60 parts of PPE and 1.2 parts (accounting for 30% of the total SEBS) of SEBS to a small internal mixer and melt-mix at 270°C for 5 minutes to obtain a PPE predispersant. Then, add 31.5 parts of HIPS, 6 parts of ADP, 2 parts of MPP, the remaining 2.8 parts of SEBS, 0.3 parts of antioxidant 1010, 0.2 parts of antioxidant 168, and the obtained PPE predispersant to a high-speed mixer and mix at room temperature for 15 minutes to obtain a uniform main premix. The main premix was added to a co-rotating parallel twin-screw extruder. The screw speed was controlled at 350 r / min, and the barrel temperature was zoned (240℃, 250℃, 260℃, 270℃, 275℃, 280℃, 275℃ from zone one to the die head). This subjected the material to alternating high-shear mixing and reverse conveying within the barrel, followed by melt extrusion, water cooling, and pelletizing to obtain alloy granules. After drying the granules at 100℃ for 4 hours, they were injection molded into standard test specimens.

[0067] Table 2: Performance test results of Examples 1-5 Analysis of the results in Table 2 shows that, after adopting the improved stepwise pretreatment and specific melt blending process, the mechanical properties of Examples 1-5, especially the impact strength and tensile strength, are further improved compared to the original examples (Table 2). For example, the impact strength of Example 1 increased from 20.1 kJ / m² to 22.5 kJ / m³. 2 The tensile strength increased from 60.5 MPa to 61.8 MPa; the impact strength of Example 2 increased from 22.0 kJ / m² to 23.8 kJ / m³. 2 The HDT was increased from 138°C to 140°C. This demonstrates that pre-dispersion treatment of PPE with some compatibilizers, combined with specific process control in a twin-screw extruder that provides alternating high-shear mixing and reverse conveying, can more effectively improve the compatibility of PPE and PS and promote the dispersion of flame retardants. This results in significantly improved alloy toughness and rigidity while maintaining excellent flame retardant performance (V-0 rating, LOI > 30%). The processing flow rate (MFR) of all embodiments remained at a good level, meeting the injection molding requirements of battery pack components.

[0068] To highlight the advantages of the present invention, the following comparative examples 1-4 are provided.

[0069] Comparative Example 1: Using a single phosphorus-based flame retardant (BDP). Raw material composition (parts by weight): PPE (η=0.40 dL / g) 60 parts, HIPS (MFR=10) 20 parts, BDP 15 parts, SEBS 5 parts, antioxidant 1010 / 168 (0.3 / 0.2) 0.5 parts. The preparation process is the same as in Example 1.

[0070] Comparative Example 2: Using a single phosphorus-based flame retardant (ADP).

[0071] Raw material composition (parts by weight): PPE (η=0.40 dL / g) 60 parts, HIPS (MFR=10) 31.5 parts, ADP 10 parts, SEBS 4 parts, antioxidant 1010 / 168 (0.3 / 0.2) 0.5 parts. The preparation process is the same as in Example 1.

[0072] Comparative Example 3: Without compatibilizer (SEBS).

[0073] Raw material composition (parts by weight): PPE (η=0.40 dL / g) 60 parts, HIPS (MFR=10) 35.5 parts, ADP 6 parts, MPP 2 parts, antioxidant 1010 / 168 (0.3 / 0.2) 0.5 parts. The preparation process is the same as in Example 1.

[0074] Comparative Example 4: Using a phosphazene / montmorillonite composite flame retardant.

[0075] Raw material composition (parts by weight): PPE (η=0.40 dL / g) 60 parts, HIPS (MFR=10) 31.5 parts, phosphazene compound 5 parts, organomontmorillonite (OMMT) 3 parts, SEBS 4 parts, antioxidant 1010 / 168 (0.3 / 0.2) 0.5 parts. The preparation process is the same as in Example 1.

[0076] Table 3: Performance test results of comparative examples 1-4 Compared with Comparative Example 1: Comparative Example 1 used 15 parts of a single flame retardant, BDP, which achieved a V-0 rating, but its impact strength (14 kJ / m²) was lower. 2 The tensile strength (52 MPa) of this invention is compared to that of embodiments of the present invention (e.g., Example 2: 23.8 kJ / m). 2 The pressure dropped significantly (63.5 MPa), and the HDT was also low (120℃). This indicates that high levels of a single flame retardant severely impair mechanical properties and heat resistance.

[0077] Compared to Comparative Example 2: Comparative Example 2 used 10 parts of a single ADP, achieving a flame retardancy rating of only V-1, failing to pass V-0, and its impact strength (18 kJ / m) was also low. 2The results are lower than those of the embodiments of the present invention. This demonstrates that the flame retardant efficiency of ADP alone is insufficient at similar addition levels.

[0078] Compared with Comparative Example 3: Comparative Example 3 does not contain the compatibilizer SEBS, and its impact strength (16.5 kJ / m) is lower. 2 The HDT (122°C) and HDT (23.8 kJ / m³) were significantly lower than those in Example 2 containing SEBS. 2 (140℃). This indicates that compatibilizers are crucial for improving the toughness and heat resistance of alloys.

[0079] Compared with Comparative Example 4: Comparative Example 4 used a phosphazene / OMMT composite flame retardant, achieving a V-0 rating with acceptable mechanical properties and an HDT of 135°C, comparable to some embodiments of this invention. However, phosphazene is typically more expensive, and the dispersion control of OMMT requires stricter control. The ADP / MPP system of this invention may have advantages in cost control and process simplicity, and the impact strength improvement is more significant, as seen in the embodiments.

[0080] This embodiment achieves an optimal balance of material flame retardancy (UL94 V-0), mechanical properties (high impact, high tensile strength), heat resistance (high HDT), and processability with a relatively low total amount of flame retardant added, through a specific compounding of ADP and MPP and combined with SEBS compatibilizer. The overall performance is significantly better than that of the comparative examples, and it is particularly suitable for new energy vehicle battery pack components with extremely high requirements for safety, reliability, and lightweighting.

[0081] Obviously, the embodiments described above are merely some embodiments of the present invention, not all embodiments. The accompanying drawings show preferred embodiments of the present invention, but do not limit the patent scope of the present invention. The present invention can be implemented in many different forms; rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the patent protection scope of this invention.

Claims

1. A composite resin material for new energy battery packs, characterized in that, By weight, it consists of the following raw materials: 40-60 parts of polyphenylene oxide (PPE); 20-40 parts of polystyrene (PS); 6-10 parts of composite flame retardant; 3-5 parts of compatibilizer; 0.2-0.8 parts of antioxidant; wherein the composite flame retardant is a compound of aluminum diethyl phosphonate (ADP) and melamine polyphosphate (MPP), with a weight ratio of ADP to MPP of (5:3) to (3:1); the PPE is first pre-dispersed with a portion of the compatibilizer, and then melt-blended with a mixture containing the remaining compatibilizer, polystyrene (PS), composite flame retardant, and antioxidant.

2. The composite resin material for new energy battery packs according to claim 1, characterized in that, The polyphenylene ether (PPE) is a pre-dispersed polyphenylene ether used to pre-melt mix with a portion of the compatibilizer to form a pre-dispersed polyphenylene ether.

3. The composite resin material for new energy battery packs according to claim 1 or 2, characterized in that, The polystyrene PS is high-impact polystyrene (HIPS), and its melt flow rate is 5–15 g / 10 min at 220°C and 10 kg load.

4. The composite resin material for new energy battery packs according to claim 1, characterized in that, The compatibilizer is styrene-ethylene / butene-styrene block copolymer SEBS or styrene-butadiene-styrene block copolymer SBS.

5. The composite resin material for new energy battery packs according to claim 1, characterized in that, The antioxidant is a compound antioxidant, composed of a primary antioxidant and a secondary antioxidant in a weight ratio of (1-2):1; the primary antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], i.e., antioxidant 1010, and the secondary antioxidant is tris(2,4-di-tert-butylphenyl) phosphite, i.e., antioxidant 168.

6. A method for preparing a composite resin material for a new energy battery pack, comprising preparing the composite resin material for a new energy battery pack as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1, premix all polyphenylene oxide (PPE) with 30%-50% compatibilizer by weight, and perform preliminary melt dispersion treatment to obtain a pre-dispersion of polyphenylene oxide (PPE). S2, polystyrene PS, composite flame retardant, residual compatibilizer, antioxidant and polyphenylene ether PPE predispersant obtained in step S1 are mixed at high speed to obtain the main premix; S3, the main premix is ​​added to a twin-screw extruder and melt-blended, extruded, cooled, and pelletized in a temperature range of 240-280℃ to obtain the composite resin material particles; wherein, the melt-blending process is carried out by controlling the screw speed and temperature distribution, applying alternating high-shear mixing and reverse conveying action to the material to promote uniform dispersion of each component.

7. The method for preparing the composite resin material for new energy battery packs according to claim 6, characterized in that, The preliminary melt dispersion treatment described in step S1 is carried out in an internal mixer or a small single-screw extruder at a temperature of 260-280°C for 3-8 minutes.

8. The method for preparing the composite resin material for new energy battery packs according to claim 6, characterized in that, The high-speed mixing time in step S2 is 10-20 minutes.

9. The method for preparing the composite resin material for new energy battery packs according to claim 6, characterized in that, In step S3, the polyphenylene oxide (PPE) predispersant and the main premix containing polystyrene (PS) and composite flame retardant are added at different stages in the twin-screw extruder so that the PPE predispersant merges with the main premix in the middle and later stages of melt blending.

10. The method for preparing the composite resin material for new energy battery packs according to claim 6, characterized in that, The screw speed of the twin-screw extruder in step S3 is 300-400 r / min.

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