High-stt high-toughness polyphenylene sulfide composite material and preparation method thereof

Abstract

This invention discloses a high STT (strain-to-toughness) high-toughness polyphenylene sulfide (PPS) composite material and its preparation method, relating to the field of polymer materials. The high STT high-toughness PPS composite material of this invention comprises the following components in parts by weight: 20-50% PPS, 0.1-1.5% coupling agent, 0.1-0.5% antioxidant, 0.1-1.5% nucleating agent, 0.1-1% release agent, 0-10% toughening agent, 25-40% hydroxylated silane-grafted carbonization inhibitor, and 20-35% fiber. This invention, through the synergistic design of a preferred matrix resin and a multi-component composite modification system, and by surface grafting modification of the carbonization inhibitor, improves the surface tracking resistance of the PPS composite material to 800V while maintaining the high toughness and high strength of the PPS composite material. This PPS composite material also exhibits excellent heat resistance, flame retardancy, dimensional stability, chemical resistance, and long-term aging stability.

Description

Technical Field

[0001] This invention relates to the field of polymer materials, and in particular to a high STT high toughness polyphenylene sulfide composite material and its preparation method. Background Technology

[0002] Polyphenylene sulfide (PPS) is a high-performance crystalline polymer with a main chain composed of alternating benzene rings and sulfur atoms. Due to its excellent high-temperature resistance, outstanding chemical corrosion resistance, inherent flame retardancy, and good dimensional stability, it has been widely used in the automotive, electronics, and aerospace industries. However, long-term practical applications have revealed two prominent inherent defects that severely limit its application in high-end scenarios, especially in high-voltage, high-reliability insulating components: First, it has high intrinsic brittleness, low notched impact strength, low elongation at break, and insufficient toughness; second, its surface tracking resistance is poor, with a typically low tracking index (CTI) (the CTI value of pure PPS resin is approximately 150V), making it prone to failure in high-voltage, humid, or polluted environments due to the formation of conductive carbonization pathways on the surface.

[0003] Currently, the CTI value of PPS can be increased to 600V by adding special modified fillers or resin blending. The market demand for PPS composites that combine high toughness (to withstand mechanical stress during assembly and operation) and a high CTI value (to ensure long-term insulation reliability) is increasingly urgent. However, existing tracking resistance evaluation standards (ASTM D3638, IEC 60112) limit the maximum test voltage to 600V, which is inconsistent with the high-voltage conditions in actual operating environments. The newly released "UL 2597" standard by UL Standards & Engagement, with its surface tracking test (STT), allows third parties to conduct standardized evaluations within the 600-900V range. Currently, there is a lack of PPS composites on the market that can achieve an STT value of 800V while maintaining high toughness. Summary of the Invention

[0004] The purpose of this invention is to provide a high STT (stable surface temperature) and high toughness polyphenylene sulfide (PPS) composite material and its preparation method, thereby solving the problems existing in the prior art. This invention, through the synergistic design of a preferred matrix resin and a multi-component composite modification system, improves the surface tracking resistance of the PPS composite material to 800V, while maintaining the high toughness and strength of the PPS composite material, and exhibiting excellent heat resistance, flame retardancy, dimensional stability, chemical resistance, and long-term aging stability.

[0005] To achieve the above objectives, the present invention provides the following solution: This invention provides a high STT high toughness polyphenylene sulfide composite material, comprising the following components in parts by weight: 20-50% polyphenylene sulfide, 0.1-1.5% coupling agent, 0.1-0.5% antioxidant, 0.1-1.5% nucleating agent, 0.1-1% release agent, 0-10% toughening agent, 25-40% hydroxylated silane grafting carbonization inhibitor, and 20-35% fiber.

[0006] Furthermore, the aforementioned polyphenylene sulfide (PPS) was produced by Shandong Mingquan Special New Materials Co., Ltd., and the model used was MAN100, which has outstanding melt flowability and melt strength.

[0007] Furthermore, the aforementioned coupling agent is a silane coupling agent.

[0008] Preferably, the silane coupling agent is at least one of aminosilane coupling agents, carboxylsilane coupling agents, and epoxysilane coupling agents.

[0009] Furthermore, the aforementioned antioxidant is at least one of hindered amine antioxidants, hindered phenolic antioxidants, phosphites, and benzophenones.

[0010] Furthermore, in the above-mentioned high STT high toughness polyphenylene sulfide composite material, the nucleating agent is at least one of zinc oxide, zinc carbonate, talc, silica, and ethylene bis-stearamide.

[0011] Furthermore, in the above-mentioned high STT high toughness polyphenylene sulfide composite material, the release agent is at least one of paraffin wax, polyethylene wax, silicone masterbatch, and stearate.

[0012] Furthermore, in the above-mentioned high STT high toughness polyphenylene sulfide composite material, the toughening agent is at least one of ethylene-glycidyl methacrylate, ethylene-1-octene block copolymer, and styrene-ethylene-butadiene copolymer.

[0013] Furthermore, in the above-mentioned high STT high toughness polyphenylene sulfide composite material, the hydroxysilane grafting carbonization inhibitor includes at least one of treated magnesium hydroxide, magnesium oxide, aluminum hydroxide, aluminum oxide, and boron nitride; the fibers include alkali-free glass fiber and wollastonite fiber; the monofilament diameter of the alkali-free glass fiber is 6-10 μm, and the median particle size of the wollastonite fiber is 5-8 μm.

[0014] This invention also provides a method for preparing high STT high-toughness polyphenylene sulfide composite materials, comprising the following steps: S1. Pre-dry polyphenylene sulfide; S2. Weigh the raw materials according to the weight ratio; place them in a high-speed mixer at 30~60℃ and mix for 8~10 minutes to obtain a mixture; the mixture includes dried polyphenylene sulfide, coupling agent, antioxidant, nucleating agent, release agent and toughening agent; The preparation process of S3.hydroxysilane-grafted carbonization inhibitor includes: placing the carbonization inhibitor in a plasma chamber for plasma treatment, and then carrying out a silane grafting reaction with a silane coupling agent hydrolysate in a high-speed mixer to obtain the hydroxysilane-grafted carbonization inhibitor.

[0015] S4. The mixture is added to the main feed port of a twin-screw extruder, and the remaining raw material components are added to the side feed port of the twin-screw extruder. After melt extrusion, the temperature is controlled at 290~320℃ and the screw speed is 150~300rpm. Granulation is then performed to obtain a high STT high toughness polyphenylene sulfide composite material. The remaining raw material components include hydroxysilane graft carbonization inhibitor and fiber. This invention also provides the application of high STT high toughness polyphenylene sulfide composite materials in high voltage, high reliability insulating components IGBT, electric vehicles, high voltage power transmission and transformation, and high voltage terminals.

[0016] The present invention discloses the following technical effects: (1) High STT. Due to its good carbonization properties, PPS has poor resistance to tracking, reaching only 150V. In the existing technology, even after composite modification, it can only reach 600V. According to the UL 2597 test standard, the present invention achieves a surface tracking resistance of 800V for PPS composite materials.

[0017] (2) High toughness. During the preparation of PPS composite materials, improving the tracking ability of the PPS surface usually reduces its mechanical properties, especially its toughness. This invention, through the synergistic effect of toughening agents and carbonization inhibitors, enables the PPS composite material to maintain high STT (Surface Tracing Toughness) while also possessing excellent toughness, with a notched impact strength of ≥8 kJ / m² for simply supported beams. 2 Elongation at break ≥2%.

[0018] (3) Selection of matrix resin. The polyphenylene sulfide (PPS) of this invention is MAN100 produced by Shandong Mingquan Special New Materials Co., Ltd., which has outstanding melt flowability and melt strength, which is conducive to fully impregnating glass fibers and other fillers during processing, ensuring that the composite material has good processability and formability and the appearance of the final product.

[0019] (4) Selection of coupling agent. The present invention selects silane coupling agents, such as aminosilane, carboxysilane or epoxysilane. Its siloxane functional groups can hydrolyze to form silanol groups on the surface of inorganic fillers such as glass fibers, and then undergo condensation reaction with the hydroxyl groups on the surface of the filler to form a strong chemical bond; at the same time, its organic functional groups (such as amino groups and epoxy groups) can undergo physical entanglement or chemical reaction with the PPS matrix, thereby constructing an effective "molecular bridge" between the inorganic filler and the organic resin, significantly improving the interfacial bonding force, improving stress transmission, and improving the mechanical properties of the composite material.

[0020] (5) Synergistic effect of antioxidants. This invention uses one or more compound systems of antioxidants such as hindered phenols, phosphites, or benzophenones. Hindered phenolic antioxidants can capture free radicals generated by the polymer during processing and use, preventing chain oxidative degradation; phosphite antioxidants can decompose hydrogen peroxide, preventing it from further initiating oxidation reactions. The synergistic effect of the two can effectively inhibit the thermo-oxidative aging of PPS under high-temperature processing and long-term use environments, maintaining the stability of material properties and service life.

[0021] (6) Synergistic effect of composite modification system. This invention introduces toughening agents (such as maleic anhydride-grafted styrene-ethylene-butadiene copolymer) and carbonization inhibitors (such as boron nitride, magnesium hydroxide, and aluminum hydroxide). As a dispersed elastomer phase, the toughening agent can induce the formation of crazing and shear bands in the matrix, thereby absorbing and dispersing impact energy. While maintaining the rigidity and heat resistance of the material, it significantly improves its impact strength and toughness. The carbonization inhibitor, through its endothermic decomposition reaction at the processing temperature and the release of water vapor, effectively inhibits the surface carbonization, yellowing, and degradation of PPS that may occur when it is locally overheated or subjected to prolonged heating, thus maintaining the appearance and performance of the product.

[0022] (7) Optimization of reinforcing fibers. Alkali-free glass fibers with a single filament diameter of 6-10 μm are selected. Glass fibers of this specification have excellent mechanical strength and appropriate flexibility, and can achieve good dispersion and appropriate aspect ratio retention during the mixing process. When combined with the interface modified by the coupling agent, the reinforcing effect of the fibers can be fully utilized, and the tensile strength, flexural strength, modulus and fatigue resistance of the composite material can be significantly improved. Wollastonite fibers with a median particle size of 5-8 μm are selected. Wollastonite fibers can play an electrical insulating role in the composite material.

[0023] (8) Hydroxysilane grafting treatment of carbonization inhibitor: The surface hydroxysilane grafting treatment of ordinary carbonization inhibitor increases the reactivity with resin and improves the dispersibility of carbonization inhibitor, which is beneficial to improving the mechanical properties of composite materials.

[0024] (9) The method for preparing high STT and high toughness polyphenylene sulfide composite materials provided by the present invention solves the problems of poor flowability and difficult processing, poor resistance to tracking, and insufficient toughness of PPS composite materials through the synergistic design of matrix resin optimization and multi-component composite modification system. The resulting product has outstanding STT value, good processing flowability, high toughness, and excellent mechanical properties. The material of the present invention can be widely used in fields with high requirements for STT value, toughness, heat resistance, and flame retardancy, such as high voltage, high reliability insulating components IGBT, electric vehicles, high voltage power transmission and transformation, etc. Detailed Implementation

[0025] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0026] It should be understood that the terminology used in this invention is for describing particular embodiments only and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0027] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0028] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0029] The terms “include,” “including,” “have,” and “contain” used in this article are all open-ended terms, meaning that they include but are not limited to.

[0030] The present invention will be further described below with reference to the embodiments. Unless otherwise specified, all chemicals and reagents used in the embodiments are commercially available.

[0031] The general preparation method of a high STT high toughness polyphenylene sulfide composite material of the present invention is as follows: S1. Pre-dried polyphenylene sulfide (PPS).

[0032] S2. Weigh the raw materials according to the following weight ratios: polyphenylene sulfide, coupling agent, antioxidant, nucleating agent, release agent, toughening agent, glass fiber, and hydroxylated silane graft carbonization inhibitor.

[0033] S3. Weigh the above-mentioned raw materials (polyphenylene sulfide, coupling agent, antioxidant, nucleating agent, release agent, and toughening agent according to the weight ratio) and place them in a high-speed mixer at 30~60℃ and mix for 8~10 minutes to obtain a mixture.

[0034] S4. Add the mixture obtained in S3 to the main feed port of the twin-screw extruder, and add the remaining raw material components, hydroxylated silane grafted carbonization inhibitor and fiber, to the side feed port of the twin-screw extruder. Control the temperature at 290~320℃ and the screw speed at 150~300rpm. After melt extrusion, cooling, granulation and drying, a high STT high toughness polyphenylene sulfide composite material is prepared.

[0035] Among them, polyphenylene sulfide (PPS) is produced by Shandong Mingquan Special New Materials Co., Ltd., and the model used is MAN100.

[0036] The coupling agent is a silane coupling agent; the silane coupling agent includes at least one of aminosilane coupling agents, carboxylsilane coupling agents, and epoxysilane coupling agents.

[0037] Among them, antioxidants include at least one of hindered amine antioxidants, hindered phenolic antioxidants, phosphites, and benzophenones.

[0038] The nucleating agent includes at least one of zinc oxide, zinc carbonate, talc, silicon dioxide, and ethylene bis-stearamide.

[0039] The release agent includes at least one of paraffin wax, polyethylene wax, silicone masterbatch, and stearate.

[0040] The toughening agent includes at least one of ethylene-glycidyl methacrylate, ethylene-1-octene block copolymer, and styrene-ethylene-butadiene copolymer.

[0041] The hydroxylated silane graft carbonization inhibitor includes at least one of the following: surface-treated magnesium hydroxide, magnesium oxide, aluminum hydroxide, aluminum oxide, and boron nitride. The fibers include alkali-free glass fiber and wollastonite fiber. The monofilament diameter of the alkali-free glass fiber is 6-10 μm, and the median particle size of the wollastonite fiber is 5-8 μm.

[0042] Example 1 A method for preparing a high STT and high toughness polyphenylene sulfide composite material specifically includes the following steps: S1. Pre-dried polyphenylene sulfide (PPS).

[0043] S2. Weigh the raw materials according to the following weight ratios: 29.1% PPS (MAN100), 0.5% coupling agent aminosilane, 0.2% antioxidant 1010, 0.2% antioxidant 168, 0.5% nucleating agent zinc oxide, 0.5% release agent, 4% toughening agent maleic anhydride grafted styrene-ethylene-butadiene copolymer, 20% alkali-free glass fiber mixed with 10% wollastonite fiber, 25% hydroxylated silane grafted magnesium hydroxide and 10% hydroxylated silane grafted boron nitride.

[0044] S3. Mixing the main raw materials to obtain a mixture: 29.1% PPS (MAN100), 0.5% coupling agent aminosilane, 0.2% antioxidant 1010, 0.2% antioxidant 168, 0.5% nucleating agent zinc oxide, 0.5% release agent paraffin wax, and 4% toughening agent maleic anhydride grafted styrene-ethylene-butadiene copolymer were used as the main raw materials and mixed in a high-speed mixer at 50°C for 8 minutes to obtain a mixture.

[0045] S4. Add the mixture obtained in S3 to the main feed port of the twin-screw extruder. Add the remaining raw material components, namely hydroxylated silane-grafted magnesium hydroxide, hydroxylated silane-grafted boron nitride, alkali-free glass fiber, and wollastonite fiber, to the side feed ports of the twin-screw extruder. Control the temperature at 310℃ and the screw speed at 250rpm. After melt extrusion, cooling, granulation, and drying, a high STT high-toughness polyphenylene sulfide composite material is prepared.

[0046] Example 2 A method for preparing a high STT and high toughness polyphenylene sulfide composite material specifically includes the following steps: S1. Pre-dried polyphenylene sulfide (PPS).

[0047] S2. Weigh the raw materials according to the following weight ratios: 24.1% PPS (MAN100), 0.5% coupling agent aminosilane, 0.2% antioxidant 1010, 0.2% antioxidant 168, 0.5% nucleating agent zinc oxide, 0.5% release agent paraffin wax, 4% toughening agent maleic anhydride grafted styrene-ethylene-butadiene copolymer, 20% alkali-free glass fiber mixed with 10% wollastonite fiber, 30% hydroxylated silane grafted magnesium hydroxide and 10% hydroxylated silane grafted boron nitride.

[0048] S3. Mixing the main raw materials to obtain a mixture: 24.1% PPS (MAN100), 0.5% coupling agent aminosilane, 0.2% antioxidant 1010, 0.2% antioxidant 168, 0.5% nucleating agent zinc oxide, 0.5% release agent paraffin wax, and 4% toughening agent maleic anhydride grafted styrene-ethylene-butadiene copolymer are used as the main raw materials and mixed in a high-speed mixer at 50°C for 8 minutes to obtain a mixture.

[0049] S4. Add the mixture obtained in S3 to the main feed port of the twin-screw extruder. Add the remaining raw material components, namely hydroxylated silane-grafted magnesium hydroxide, hydroxylated silane-grafted boron nitride, alkali-free glass fiber, and wollastonite fiber, to the side feed ports of the twin-screw extruder. Control the temperature at 310℃ and the screw speed at 250rpm. After melt extrusion, cooling, granulation, and drying, a high STT high-toughness polyphenylene sulfide composite material is prepared.

[0050] Example 3 The preparation steps in this embodiment are the same as those in Example 1, except that the coupling agent aminosilane is replaced with the coupling agent carboxysilane.

[0051] Example 4 The preparation steps in this embodiment are the same as those in Example 1, except that the coupling agent aminosilane is replaced with the coupling agent epoxysilane.

[0052] Example 5 This embodiment has the same preparation steps as Example 1, except that antioxidants 1010 and 168 are replaced with antioxidants 1076, UV-531 and HALS.

[0053] Example 6 The preparation steps in this embodiment are the same as those in Example 1, except that the nucleating agent zinc oxide is replaced with talc powder.

[0054] Example 7 The preparation steps in this embodiment are the same as those in Example 1, except that the nucleating agent zinc oxide is replaced with silicon dioxide.

[0055] Example 8 The preparation steps in this embodiment are the same as those in Example 1, except that the nucleating agent zinc oxide is replaced with ethylene bis-stearamide.

[0056] Example 9 The preparation steps in this embodiment are the same as in Example 1, except that the raw material release agent paraffin is replaced with polyethylene wax.

[0057] Example 10 The preparation steps in this embodiment are the same as in Example 1, except that the raw material release agent paraffin is replaced with silicone masterbatch.

[0058] Example 11 The preparation steps in this embodiment are the same as those in Example 1, except that the raw material release agent paraffin is replaced with zinc stearate.

[0059] Example 12 The preparation steps in this embodiment are the same as those in Example 1, except that the toughening agent maleic anhydride-grafted styrene-ethylene-butadiene copolymer is replaced with ethylene-glycidyl methacrylate.

[0060] Example 13 The preparation steps in this embodiment are the same as those in Example 1, except that the toughening agent maleic anhydride-grafted styrene-ethylene-butadiene copolymer is replaced with ethylene-1-octene block copolymer.

[0061] Example 14 The preparation steps in this embodiment are the same as in Example 1, except that the raw material hydroxylated silane grafted with the carbonization inhibitor magnesium hydroxide is replaced with magnesium oxide.

[0062] Example 15 The preparation steps in this embodiment are the same as in Example 1, except that the raw material hydroxylated silane grafted with the carbonization inhibitor magnesium hydroxide is replaced with aluminum hydroxide.

[0063] Example 16 The preparation steps in this embodiment are the same as in Example 1, except that the raw material hydroxylated silane grafted with the carbonization inhibitor magnesium hydroxide is replaced with aluminum oxide.

[0064] Example 17 The preparation steps in this embodiment are the same as those in Example 1, the only difference being the ratio of the raw material components.

[0065] Raw material composition: 20.5% PPS (MAN100), 1.5% coupling agent aminosilane, 0.25% antioxidant 1010, 0.25% antioxidant 168, 1.5% nucleating agent zinc oxide, 1% release agent, 5% toughening agent maleic anhydride grafted styrene-ethylene-butadiene copolymer, 20% alkali-free glass fiber and 10% wollastonite fiber mixture, 25% hydroxylated silane grafted magnesium hydroxide and 15% hydroxylated silane grafted boron nitride.

[0066] Example 18 The preparation steps in this embodiment are the same as those in Example 1, the only difference being the ratio of the raw material components.

[0067] Raw material composition: 50% PPS (MAN100), 0.1% coupling agent aminosilane, 0.05% antioxidant 1010, 0.05% antioxidant 168, 0.1% nucleating agent zinc oxide, 0.1% release agent, 4.6% toughening agent maleic anhydride grafted styrene-ethylene-butadiene copolymer, 10% alkali-free glass fiber and 10% wollastonite fiber mixture, 15% hydroxylated silane grafted magnesium hydroxide and 10% hydroxylated silane grafted boron nitride.

[0068] Example 19 The preparation steps in this embodiment are the same as those in Example 1, the only difference being the ratio of the raw material components.

[0069] Raw material composition: 29.6% PPS (MAN100), 0.1% coupling agent aminosilane, 0.05% antioxidant 1010, 0.05% antioxidant 168, 0.1% nucleating agent zinc oxide, 0.1% release agent, 25% alkali-free glass fiber mixed with 10% wollastonite fiber, 25% hydroxylated silane grafted with magnesium hydroxide and 10% hydroxylated silane grafted with boron nitride.

[0070] Comparative Example 1 A method for preparing a polyphenylene sulfide composite material, the specific steps of which are the same as those in Example 1, the only difference being the composition of the raw materials: 29.1% PPS (MAN100), 0.5% coupling agent aminosilane, 0.2% antioxidant 1010, 0.2% antioxidant 168, 0.5% nucleating agent zinc oxide, 0.5% release agent paraffin wax, 4% toughening agent maleic anhydride grafted styrene-ethylene-butadiene copolymer, 20% alkali-free glass fiber mixed with 10% wollastonite fiber, and 35% hydroxylated silane grafted calcium carbonate.

[0071] Comparative Example 2 A method for preparing a polyphenylene sulfide composite material, the specific steps of which are the same as those in Example 1, the only difference being the composition of the raw materials: 29.1% PPS (MAN100), 0.5% coupling agent aminosilane, 0.2% antioxidant 1010, 0.2% antioxidant 168, 0.5% nucleating agent zinc oxide, 0.5% release agent, 4% toughening agent maleic anhydride grafted styrene-ethylene-butadiene copolymer, 20% alkali-free glass fiber mixed with 10% wollastonite fiber, 25% untreated magnesium hydroxide and 10% untreated boron nitride.

[0072] Comparative Example 3 A method for preparing a high STT and high toughness polyphenylene sulfide composite material specifically includes the following steps: S1. Pre-dried polyphenylene sulfide (PPS).

[0073] S2. Weigh the raw materials according to the following weight ratios: 43.3% PPS (MAN100), 0.5% aminosilane coupling agent, 0.1% antioxidant 1010, 0.1% antioxidant 168, 0.5% nucleating agent zinc oxide, 0.5% release agent paraffin wax, 20% alkali-free glass fiber mixed with 10% wollastonite fiber, and 25% hydroxylated silane-grafted magnesium hydroxide. The polyphenylene sulfide (PPS) used is produced by Shandong Mingquan Special New Materials Co., Ltd., and the model used is MAN100.

[0074] S3. Mixing the main raw materials to obtain a mixture: 43.3% PPS (MAN100), 0.5% aminosilane coupling agent, 0.1% antioxidant 1010, 0.1% antioxidant 168, 0.5% nucleating agent zinc oxide, and 0.5% release agent paraffin are used as the main raw materials and mixed in a high-speed mixer at 50°C for 8 minutes to obtain a mixture.

[0075] S4. Add the mixture obtained in S3 to the main feed port of the twin-screw extruder. Add the remaining raw material components, namely 20% alkali-free glass fiber, 10% wollastonite fiber and 25% hydroxylated silane-grafted magnesium hydroxide, to the side feed ports of the twin-screw extruder. Control the temperature at 310℃ and the screw speed at 250 rpm. After melt extrusion, cooling, granulation and drying, a high STT high toughness polyphenylene sulfide composite material is prepared.

[0076] Comparative Example 4 A method for preparing a high STT and high toughness polyphenylene sulfide composite material specifically includes the following steps: S1. Pre-dried polyphenylene sulfide (PPS).

[0077] S2. Weigh the raw materials according to the following weight ratios: 39.1% PPS (MAN100), 0.5% aminosilane coupling agent, 0.2% antioxidant 1010, 0.2% antioxidant 168, 0.5% nucleating agent zinc oxide, 0.5% release agent paraffin wax, 4% toughening agent maleic anhydride grafted styrene-ethylene-butadiene copolymer, 20% alkali-free glass fiber mixed with 10% wollastonite fiber, and 25% hydroxylated silane grafted magnesium hydroxide.

[0078] S3. Mixing the main raw materials to obtain a mixture: 39.1% PPS (MAN100), 0.5% aminosilane coupling agent, 0.2% antioxidant 1010, 0.2% antioxidant 168, 0.5% nucleating agent zinc oxide, 0.5% release agent paraffin wax, and 4% toughening agent maleic anhydride grafted styrene-ethylene-butadiene copolymer were used as the main raw materials and mixed in a high-speed mixer at 50°C for 8 minutes to obtain a mixture.

[0079] S4. Add the mixture obtained in S3 to the main feed port of the twin-screw extruder. Add the weighed remaining raw material components, hydroxylated silane-grafted magnesium hydroxide, alkali-free glass fiber, and wollastonite fiber, to the side feed ports of the twin-screw extruder respectively. Control the temperature at 310℃ and the screw speed at 250rpm. After melt extrusion, cooling, granulation, and drying, a high STT high-toughness polyphenylene sulfide composite material is prepared.

[0080] Comparative Example 5 A method for preparing a high STT and high toughness polyphenylene sulfide composite material specifically includes the following steps: S1. Pre-dried polyphenylene sulfide (PPS).

[0081] S2. Weigh the raw materials according to the following weight ratios: 29.1% PPS (MAN100), 0.5% coupling agent aminosilane, 0.2% antioxidant 1010, 0.2% antioxidant 168, 0.5% nucleating agent zinc oxide, 0.5% release agent, 4% toughening agent maleic anhydride grafted styrene-ethylene-butadiene copolymer, 30% alkali-free glass fiber, 25% hydroxylated silane grafted magnesium hydroxide and 10% hydroxylated silane grafted boron nitride.

[0082] S3. Mixing the main raw materials to obtain a mixture: 29.1% PPS (MAN100), 0.5% coupling agent aminosilane, 0.2% antioxidant 1010, 0.2% antioxidant 168, 0.5% nucleating agent zinc oxide, 0.5% release agent paraffin wax, and 4% toughening agent maleic anhydride grafted styrene-ethylene-butadiene copolymer are placed in a high-speed mixer at 50°C and mixed for 8 minutes to obtain a mixture.

[0083] S4. Add the mixture obtained in S3 to the main feed port of the twin-screw extruder. Add the remaining raw material components, alkali-free glass fiber, hydroxylated silane-grafted magnesium hydroxide, and hydroxylated silane-grafted boron nitride, to the side feed ports of the twin-screw extruder respectively. Control the temperature at 310℃ and the screw speed at 250rpm. After melt extrusion, cooling, granulation, and drying, a high STT high-toughness polyphenylene sulfide composite material is prepared.

[0084] Performance testing The material granules obtained from the above embodiments and comparative examples were added to an injection molding machine and molded into standard specimens for testing. Tensile strength and elongation were tested according to ISO 527 standard, flexural strength and flexural modulus were tested according to ISO 178 standard, notched impact strength of simply supported beams was tested according to ISO 179 standard, and surface tracking resistance was tested according to IEC 60112 / UL 2597 standard. The performance test results of the embodiments and comparative examples are shown in Table 1.

[0085] Table 1 Performance test results of the examples and comparative examples

[0086] The performance comparison of the examples and comparative examples 1-5 in Table 1 shows that the carbonization inhibitor has a significant impact on the surface tracking results, but it also affects the mechanical properties. The mechanical properties of the composite material can be improved by increasing the active groups of the carbonization inhibitor through surface grafting modification. The choice of toughening agent has a significant impact on the notched impact strength of the simply supported beam, showing an improvement in toughness, but it has little impact on the surface tracking results.

[0087] The performance comparison of the examples shows that the three test indicators—surface tracking, mechanical properties, and toughness—are interdependent and cannot be satisfied simultaneously. The synergistic addition of carbonization inhibitors and toughening agents, along with surface grafting modification, allows the PPS composite material to achieve a surface tracking voltage of 800V while maintaining a notched impact strength of 8kJ / m. 2 The elongation at break reaches 2%.

[0088] The polyphenylene sulfide composite material prepared by this invention achieves high STT and high toughness.

[0089] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A high STT high toughness polyphenylene sulfide composite material, characterized in that, It includes the following components in parts by weight: 20-50% polyphenylene sulfide, 0.1-1.5% coupling agent, 0.1-0.5% antioxidant, 0.1-1.5% nucleating agent, 0.1-1% release agent, 0-10% toughening agent, 25-40% hydroxylated silane grafting carbonization inhibitor, and 20-35% fiber.

2. The high STT high toughness polyphenylene sulfide composite material as described in claim 1, characterized in that, The coupling agent is a silane coupling agent.

3. The high STT high toughness polyphenylene sulfide composite material as described in claim 2, characterized in that, The silane coupling agent is at least one of aminosilane coupling agents, carboxylsilane coupling agents, and epoxysilane coupling agents.

4. The high STT high toughness polyphenylene sulfide composite material as described in claim 1, characterized in that, The antioxidant is at least one of hindered amine antioxidants, hindered phenolic antioxidants, phosphites, and benzophenones.

5. The high STT high toughness polyphenylene sulfide composite material as described in claim 1, characterized in that, The nucleating agent is at least one of zinc oxide, talc, silicon dioxide, and ethylene bis-stearamide.

6. The high STT high toughness polyphenylene sulfide composite material as described in claim 1, characterized in that, The release agent is at least one of paraffin wax, polyethylene wax, silicone masterbatch, and stearate.

7. The high STT high toughness polyphenylene sulfide composite material as described in claim 1, characterized in that, The toughening agent is at least one of ethylene-glycidyl methacrylate, ethylene-1-octene block copolymer, and maleic anhydride-grafted styrene-ethylene-butadiene copolymer.

8. The high STT high toughness polyphenylene sulfide composite material as described in claim 1, characterized in that, The carbonization inhibitor is at least one of magnesium hydroxide, magnesium oxide, aluminum hydroxide, aluminum oxide, and boron nitride grafted with surface hydroxysilane; the fiber includes alkali-free glass fiber and wollastonite fiber; the monofilament diameter of the alkali-free glass fiber is 6-10 μm; the median particle size of the wollastonite fiber is 5-8 μm.

9. The method for preparing the high STT high toughness polyphenylene sulfide composite material according to any one of claims 1-8, characterized in that, The preparation method includes the following steps: S1. Pre-dry polyphenylene sulfide; S2. Weigh the raw materials according to the weight ratio; mix them to obtain a mixture; the mixture includes the dried polyphenylene sulfide, coupling agent, antioxidant, nucleating agent, release agent and toughening agent; S3. The preparation process of the hydroxysilane grafted carbonization inhibitor includes: placing the carbonization inhibitor in a plasma box for plasmaization, and then carrying out a silane grafting reaction with a silane coupling agent hydrolysate in a high-speed mixer to obtain the hydroxysilane grafted carbonization inhibitor. S4. The mixture is added to the main feed port of a twin-screw extruder, and the remaining raw material components are added to the side feed port of the twin-screw extruder. After melt extrusion and granulation, a high STT high-toughness polyphenylene sulfide composite material is obtained. The remaining raw material components include the hydroxysilane graft carbonization inhibitor and the fiber.

10. The application of the high STT high toughness polyphenylene sulfide composite material as described in any one of claims 1-8 in high-voltage, high-reliability insulating components IGBTs, electric vehicles, high-voltage power transmission and transformation, and high-voltage terminals.

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