High ipt cold-heat cycle resistant polyphenylene sulfide composite material, preparation method and application thereof

Abstract

The application discloses a kind of high IPT cold-heat cycle resistant polyphenylene sulfide composite material and preparation method and application.The composite material includes the following components by mass percentage:PPS resin 44.1~60.5%,N,N-4,4-diphenylmethane bismaleimide 6~10%,compatibility agent 3~5%,glass fiber 30~40%,antioxidant 0.3~0.5%,lubricant 0.2~0.4%.The composite material has excellent bevel electric leakage tracking resistance,can reach 1KV by IPT test,has good cold-heat cycle resistance,at low temperature-40 DEG C,2 hours and high temperature 150 DEG C,2 hours;High-low temperature switching time is 3 minutes,crack and no crack are generated after 300 cycles,which can be used for preparing busbar and module cover plate products in new energy materials.

Description

Technical Field

[0001] This invention belongs to the field of polymer material modification technology, specifically relating to a high IPT-resistant polyphenylene sulfide composite material for thermal cycling, its preparation method, and its application. Background Technology

[0002] Polyphenylene sulfide (PPS) is a thermoplastic polymer containing phenyl sulfide groups in its molecular chain. Commonly known as "plastic gold," it ranks first among the six major special engineering plastics due to its excellent physical and chemical properties and is also one of the eight major aerospace materials. PPS has a symmetrical rigid backbone and is a partially crystalline polymer composed of repeating para-substituted benzene rings and sulfur atoms. It is an engineering plastic that also possesses the properties of thermosetting plastics. The relative density of PPS is 1.36 g / cm³. 2 With a melting point of 280-290℃ and a decomposition temperature greater than 400℃, PPS possesses extremely high heat resistance, excellent creep and fatigue resistance, and a low linear coefficient of thermal expansion. It is a special engineering plastic that can replace metals, hence its nickname "super engineering plastic." PPS also exhibits excellent mechanical properties, dimensional accuracy, hydrolysis resistance, and electrical insulation, maintaining superior electrical properties even at high temperatures, high humidity, and high frequencies. PPS resin itself is flame-retardant, achieving UL94 V-0 rating without the need for flame retardants. However, pure PPS is often used in fiber products due to its poor impact resistance. When used in thermoplastic composites, it requires modification. Modified PPS exhibits excellent heat resistance, with short-term heat resistance reaching 260℃ and long-term use at 200-240℃. It also has low water absorption and good chemical corrosion resistance. PPS is widely used in numerous fields such as automotive, electronics, aerospace, machinery, and new energy.

[0003] In low-voltage applications, the Comparative Tracking Test (CTI) is used to characterize the tracking resistance of materials, with a testing range currently up to 800V. However, with continuously increasing voltages, many electronic components in new energy sources operate at voltages far exceeding 800V. Therefore, in high-voltage applications, CTI cannot accurately reflect the tracking resistance of materials. Instead, the Inclined Plate Test (IPT) is used. IPT simulates the corrosion resistance and insulation performance of materials exposed to high-voltage energy storage effects (≥1.0KV) under harsh outdoor conditions, including contaminants and humid environments. The test method involves tilting the sample at a 45° angle, with electrodes installed at the top and bottom of the downward-sloping surface. The test voltage ranges from 1KV to 35KV. The failure criteria in ASTM D2303-2013 are the formation of holes and burning, a tracking length reaching 25mm, or a tracking time of less than 60 minutes. IPT testing is primarily used in new energy applications and outdoor high-voltage environments. PPS possesses excellent electrical properties and heat resistance, but it suffers from drawbacks such as low impact resistance and low CTI (due to the unique benzene ring structure of PPS, it easily generates a large amount of heat under voltage load, leading to easy carbonization and short circuits on the product surface; the CTI of ordinary PPS is only 150V). These shortcomings limit its design application in lithium battery components for electric vehicles. With the rapid development of new energy vehicles, their components need to withstand humid and hot environments, requiring high levels of durability, IPT (Insulation Power Test), and flame retardancy. Busbars and module covers are among the electrical components in new energy vehicles that carry high voltage and high current. They consist of metal covered with insulating material, requiring the insulating material to have high resistance to thermal shock and an IPT test of at least 1.0KV.

[0004] Chinese patent application number 202210768393.5 discloses a high CTI polyphenylene sulfide composite material and its preparation method. The method uses a combination of modified magnesium hydroxide and a modified toughening agent, which imparts a CTI as high as 600V and good mechanical properties to the material. Due to the addition of magnesium hydroxide, the highest impact strength of this system is only 7.6 KJ / m. 2 It failed the thermal cycling test of lithium battery components, and the system also failed the more stringent IPT1.0KV test.

[0005] Chinese patent application No. 202311768640.2 discloses a method for preparing high CTI polyphenylene sulfide compositions based on multi-dimensional formulation design, its application, and a polyphenylene sulfide composite material prepared using a multi-dimensional formulation design method with special nano-clay, gallium hydroxyl oxide, silane-modified epoxy resin, and nano-cerium oxide as the stabilizer. The system exhibits an impact strength of only 8.7 KJ / m². 2 It also failed the thermal cycling test of battery-related components. In addition, the highest CTI of the system is only 500V, which cannot pass the IPT 1.0KV test.

[0006] Currently, there are almost no polyphenylene sulfide composite materials with high IPT resistance to thermal cycling, and related research is still in its early stages. Therefore, developing high-impact polyphenylene sulfide composite materials with high IPT values ​​(≥1.0KV) has great market significance and economic value. The preparation of polyphenylene sulfide composite materials with high IPT resistance to thermal cycling is of great significance in the application and development of new energy materials. Summary of the Invention

[0007] The primary objective of this invention is to overcome the shortcomings and deficiencies of existing polyphenylene sulfide composite material technology and provide a high IPT polyphenylene sulfide composite material resistant to thermal cycling.

[0008] Another object of the present invention is to provide a method for preparing the above-mentioned high IPT resistant polyphenylene sulfide composite material for thermal cycling.

[0009] Another object of the present invention is to provide the application of the above-mentioned high IPT resistant polyphenylene sulfide composite material for thermal cycling.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] A high IPT (intensity per unit area) resistant polyphenylene sulfide (PPS) composite material for thermal cycling comprises the following components by mass percentage: 44.1–60.5% PPS resin, 6–10% N,N-4,4-diphenylmethane bismaleimide, 3–5% compatibilizer, 30–40% glass fiber, 0.3–0.5% antioxidant, and 0.2–0.4% lubricant; preferably comprising the following components by mass percentage: 46.3–60.3% PPS resin, 6–10% N,N-4,4-diphenylmethane bismaleimide, 3–5% compatibilizer, 30–40% glass fiber, 0.3–0.5% antioxidant, and 0.2–0.4% lubricant.

[0012] The PPS resin is a linear polyphenylene sulfide resin with a melt index of 80-200 g / 10 min at 316℃ and 5 kg; more preferably, it is a linear polyphenylene sulfide resin with a melt index of 140-160 g / 10 min at 316℃ and 5 kg; and most preferably, it is a linear polyphenylene sulfide resin with a melt index of 150 g / 10 min at 316℃ and 5 kg, such as GAC02 from Chongqing Jushi.

[0013] The N,N-4,4-diphenylmethane bismaleimide is N,N-4,4-diphenylmethane bismaleimide with a purity greater than 99.5%, preferably BMI-01 from Honghu Shuangma New Materials.

[0014] The compatibilizer is preferably a copolymer of styrene-N-phenylmaleimide-maleic anhydride; more preferably, the Tg is a copolymer of styrene-N-phenylmaleimide-maleic anhydride at 196°C; and most preferably, MS-L2A from Denki Kagaku Corporation of Japan.

[0015] The glass fiber is E glass fiber; preferably E glass fiber with a chopped length of 3-5 cm and a single filament thickness of 8-10 μm, more preferably E glass fiber from Chongqing International Composite Materials Co., Ltd., specifically ECS309A-3-H.

[0016] The antioxidant is an asymmetric hindered phenolic antioxidant, preferably Lowinox 1790.

[0017] The lubricant is rice bran wax, preferably Clariant's Licocare RBW300.

[0018] The high IPT mentioned above refers to the ability to withstand tracking resistance tests using the inclined plate method with a voltage of 1000V.

[0019] The above-mentioned high IPT resistant polyphenylene sulfide composite material is prepared by melt blending using a common twin-screw extruder. The preferred preparation method includes the following steps: adding components other than N,N-4,4-diphenylmethane bismaleimide and glass fiber (such as PPS resin, compatibilizer, antioxidant, lubricant, etc.) from the main feed port of the twin-screw extruder, adding N,N-4,4-diphenylmethane bismaleimide and glass fiber from the two side feed ports respectively, and then melting and extruding the mixture in the twin-screw extruder, followed by cooling, air drying, and pelletizing to obtain the high IPT resistant polyphenylene sulfide composite material.

[0020] The twin-screw extruder is a twin-screw extruder with a length-to-diameter ratio of 40.

[0021] The preferred extrusion conditions are as follows: extrusion temperature of 270–290°C and screw speed of 250–400 rpm.

[0022] The aforementioned high IPT-resistant polyphenylene sulfide composite material has high IPT, good impact performance and flame retardant properties, making it suitable for the preparation of new energy material components, especially for busbars and module cover products.

[0023] Compared with the prior art, this application has the following beneficial effects:

[0024] (1) The high IPT resistant polyphenylene sulfide composite material provided by the present invention has an IPT (tracking resistance test) of 1KV.

[0025] (2) The present invention uses a copolymer of styrene-N-phenylmaleimide-maleic anhydride and N,N-4,4-diphenylmethane bismaleimide to obtain a high IPT cold and heat cycle resistant polyphenylene sulfide composite material with good cold and heat cycle resistance. It does not crack or show any cracks after 300 cycles at a low temperature of -40℃ for 2 hours and a high temperature of 150℃ for 2 hours; the high and low temperature switching time is 3 minutes.

[0026] (3) The N,N-4,4-diphenylmethane bismaleimide used in this invention has superior electrical properties, especially resistance to tracking, which helps to improve the safety of new energy material components under humid and hot conditions. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto.

[0028] Example 1

[0029] The composition of high IPT cold and heat resistant polyphenylene sulfide composites S1 to S6 is shown in Table 1, and the composition of polyphenylene sulfide composites C1 to C8 is shown in Table 2.

[0030] The preparation steps are as follows: Weigh each raw material according to the material ratios in Tables 1 and 2 below. Add the components other than N,N-4,4-diphenylmethane bismaleimide and glass fiber (such as PPS resin, styrene-N-phenylmaleimide-maleic anhydride copolymer, antioxidant, lubricant, etc.) from the main feed port of the twin-screw extruder. Add N,N-4,4-diphenylmethane bismaleimide and glass fiber from the two side feed ports respectively. After melt blending and extrusion in the twin-screw extruder, the mixture is cooled, air-dried, and pelletized to obtain a high IPT resistant polyphenylene sulfide composite material.

[0031] The twin-screw extruder is a twin-screw extruder with a length-to-diameter ratio of 40.

[0032] The preferred extrusion conditions are as follows: extrusion temperature is 270-290℃ (before the glass fiber inlet), 270-280℃ (between the glass fiber inlet and the vacuum port), and 280-290℃ (after the vacuum port); screw speed is 250-400 rpm.

[0033] The composite materials prepared in Examples S1-S6 and Comparative Examples C1-C8 were tested. First, test specimens were prepared under the same injection molding conditions (baking temperature 120℃, baking time 4 hours; nozzle, front section, middle section, and rear section temperatures of the injection molding machine were 300℃, 290℃, 290℃, and 285℃ respectively; screw speed of the injection molding machine was 60 rpm; mold temperature was 120℃; injection pressure was 90 MPa; injection time was 2 seconds; holding pressure was 60 MPa; holding time was 3 seconds; cooling time was 8 seconds; and back pressure was 10 MPa). The specific physical property test items are as follows:

[0034] IPT (Impedance Tracking) Test: The inclined plane tracking resistance test was conducted according to ASTM D2303-2013, using the constant voltage method. Example test voltage: 1KV.

[0035] Flame retardant test conditions: Tested according to UL94 standard, thickness 0.8±0.15mm.

[0036] Tensile strength: Tested according to ISO 527 standard at a speed of 10 mm / min.

[0037] Bending strength: Tested according to ISO 178 standard at a test speed of 2 mm / min.

[0038] Unnotched impact strength of simply supported beams: tested according to ISO 179 standard, notch type A.

[0039] Relative Tracking Index (CTI): Tested according to IEC 60112 standard (sample size 100mm*100mm*3mm), unit V;

[0040] Thermal cycling test: The sample was treated according to GB / T2423.22-2012 standard: low temperature -40℃ for 2 hours; high temperature 150℃ for 2 hours; high and low temperature switching time 3 minutes, cycled 300 times, and after completion, observe whether there is cracking or cracks.

[0041] The results are shown in Tables 1 and 2.

[0042] Table 1: Technical Solutions and Performance Results of the Examples

[0043]

[0044] Note: Pass means passed.

[0045] Table 2: Comparative Technical Solutions and Performance Results

[0046]

[0047] Note: ① Pass means passed; NG means failed.

[0048] ② The modified toughening agents are maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer (Kertene FG1901GT) and polystyrene (Ronfalin, LyondellBasell). ® A mixture of maleic anhydride grafting rate of approximately 1.1% and styrene content of approximately 63%, obtained by melt mixing, extrusion and pelletizing of PS 5112 at a mass ratio of 7:3 at 190-230℃.

[0049] As can be seen from Examples S1 to S6, the high IPT-resistant polyphenylene sulfide composite material for thermal cycling produced by the method of the present invention has excellent resistance to inclined plane tracking test and thermal cycling performance. The IPT can pass 1KV and the 800V CTI can pass.

[0050] Comparative examples C1 to C3 show that BMI-01 failed both the IPT and thermal cycling tests when added alone, and MS-L2A failed both the IPT and CTI tests when added alone. This demonstrates that the two have a good synergistic effect, and their combined use improves the IPT performance and thermal cycling resistance of the system. The inventors speculate that this may be because N,N-4,4-diphenylmethane bismaleimide in the system has a low melting point and flows rapidly to the surface during heating. In addition, due to the interfacial reinforcement and compatibility of the styrene-N-phenylmaleimide-maleic anhydride copolymer, the two work synergistically to stabilize the PPS resin and maleimide, thereby forming a protective layer around the PPS. This simultaneously improves the polymer's IPT, CTI, and impact strength, thus enhancing its thermal cycling resistance.

[0051] Comparative Example C4's MS-L2A was below the addition range of this invention, resulting in a tracking duration >60 min and poor resistance to thermal cycling. Comparative Example C5's MS-L2A was above the addition range of this invention, resulting in a tracking duration >60 min and decreased flame retardant effect. Comparative Example C6's BMI-01 was above the addition range of this invention, resulting in a tracking duration >60 min and poor resistance to thermal cycling. Comparative Example C7's BMI-01 was below the addition range of this invention, resulting in failure to pass the IPT 1000V test. Comparative Examples C4 to C7 show that when BMI-01 or MS-L2A is outside the addition range of this invention, the purpose of this invention is not achieved. The inventors speculate that although these two have a synergistic effect, it is limited to a certain range. Once this range is exceeded, PPS and BMI-01 cannot fully combine, leading to failure in IPT, thermal cycling resistance, or flame retardancy tests.

[0052] Comparative Example C8 shows that although the high CTI polyphenylene sulfide composite material using other invention systems can achieve a CTI of 600V, it fails both the IPT and 800V CTI tests. In addition, although this system has added a modified toughening agent, the amount of modified magnesium hydroxide added is too large, resulting in very low impact performance of the composite material, which cannot pass the thermal cycling test. This proves that this type of system is not suitable for use as a material for new energy busbars and module cover plates.

[0053] In summary, the high IPT-resistant polyphenylene sulfide composite material provided by this invention can achieve an IPT of 1KV and exhibit excellent resistance to thermal cycling. It can be used to prepare busbars and module cover plates in new energy materials.

[0054] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A high IPT (intrinsic permeability) resistant polyphenylene sulfide composite material for thermal cycling, characterized in that... It includes the following components by weight percentage: PPS resin 44.1–60.5%, N,N-4,4-diphenylmethane bismaleimide 6–10%, compatibilizer 3–5%, glass fiber 30–40%, antioxidant 0.3–0.5%, and lubricant 0.2–0.4%; The compatibilizer is a copolymer of styrene-N-phenylmaleimide-maleic anhydride.

2. The high IPT resistant polyphenylene sulfide composite material according to claim 1, characterized in that... It includes the following components by weight percentage: PPS resin 46.3-60.3%, N,N-4,4-diphenylmethane bismaleimide 6-10%, compatibilizer 3-5%, glass fiber 30-40%, antioxidant 0.3-0.5%, and lubricant 0.2-0.4%.

3. The high IPT (intense polyphenylene sulfide) resistant to thermal cycling polyphenylene sulfide composite material according to claim 1 or 2, characterized in that: The PPS resin is a linear polyphenylene sulfide resin with a melt index of 80-200 g / 10 min at 316℃ and 5 kg. The glass fiber is E-glass fiber.

4. The high IPT-resistant polyphenylene sulfide composite material according to claim 3, characterized in that: The PPS resin is a linear polyphenylene sulfide resin with a melt index of 140-160 g / 10 min at 316℃ and 5 kg. The compatibilizer is a copolymer of styrene-N-phenylmaleimide-maleic anhydride at 196°C. The glass fiber is E-glass fiber with a chopped length of 3-5 cm and a single filament thickness of 8-10 μm.

5. The high IPT (intense polyphenylene sulfide) resistant to thermal cycling polyphenylene sulfide composite material according to claim 1 or 2, characterized in that: The antioxidant mentioned is an asymmetric hindered phenolic antioxidant; The lubricant mentioned is rice bran wax.

6. The method for preparing the high IPT resistant polyphenylene sulfide composite material according to any one of claims 1 to 5, characterized in that... The process includes the following steps: adding all components except N,N-4,4-diphenylmethane bismaleimide and glass fiber from the main feed port of a twin-screw extruder, and adding N,N-4,4-diphenylmethane bismaleimide and glass fiber from the two side feed ports respectively. After melt blending and extrusion in a twin-screw extruder, the mixture is cooled, air-dried, and pelletized to obtain a high IPT-resistant polyphenylene sulfide composite material resistant to thermal cycling.

7. The preparation method according to claim 6, characterized in that: The twin-screw extruder is a twin-screw extruder with a length-to-diameter ratio of 40; The extrusion conditions are as follows: extrusion temperature is 270-290℃, and screw speed is 250-400 rpm.

8. The application of the high IPT-resistant thermal cycling-resistant polyphenylene sulfide composite material according to any one of claims 1 to 5 in the preparation of new energy material components.

9. The application according to claim 8, characterized in that: The new energy material components mentioned above are busbars and module cover plates.

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