Halogen-free flame-retardant polyphenyl ether composite material as well as preparation method and application thereof

Abstract

The invention discloses a halogen-free flame-retardant polyphenyl ether composite material as well as a preparation method and application thereof, and belongs to the technical field of high polymer materials. The composite material is prepared from the following components in parts by weight: 40-70 parts of polyphenyl ether resin, 10-30 parts of high impact polystyrene resin, 4-8 parts of SEBS (Styrene-Ethylene-Butylene-Styrene) resin, 5-10 parts of organic and inorganic composite flame retardant, 3-8 parts of phosphate flame retardant, 1-5 parts of polyborosiloxane and auxiliaries. The core of the organic-inorganic composite flame retardant is that the organic-inorganic composite flame retardant is a core-shell structure particle which takes magnesium-aluminum hydrotalcite and nano silicon dioxide as a core and melamine cyanurate as a shell according to a specific proportion. Through the synergistic effect of all the components, especially the core-shell structure, the dispersity and interfacial compatibility are effectively improved, so that the material achieves excellent flame retardance while maintaining high impact strength and heat resistance, and the UL-94 V-0 grade can still be met even under the condition of a 0.8 mm thin wall. The material is particularly suitable for preparing thin-wall electronic and electrical appliance shells and new energy automobile parts with harsh performance requirements.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer materials, in particular to a halogen-free flame-retardant polyphenyl ether composite material and a preparation method and application thereof. BACKGROUND

[0002] Polyphenyl ether (PPO) resin is widely used in the fields of electronic appliances and automobiles due to its excellent heat resistance, dimensional stability, electrical insulation and mechanical strength. However, its inherent poor processing fluidity and high cost have prompted the industry to often blend it with high-impact polystyrene (HIPS). The introduction of HIPS improves the processability and reduces the cost, but also brings problems of decreased flame-retardant grade and easy melting and dripping.

[0003] Currently, the core challenge faced by halogen-free flame-retardant PPO / HIPS systems is how to balance flame retardancy, mechanical properties and processability. Traditional flame retardants such as magnesium hydroxide and aluminum hydroxide require high addition amount, which seriously damages the toughness of the material; phosphorus-nitrogen intumescent flame retardants are relatively efficient, but still have problems such as poor compatibility with the matrix, easy migration and insufficient support for thin-wall flame retardation. In particular, with the development of electronic products towards light, thin, short and small, it is extremely demanding to achieve UL-94 V-0 level flame retardation at a thickness of 0.8 mm or even thinner. Therefore, it is of great significance and market value to develop a halogen-free flame-retardant PPO composite material with high efficiency, high impact strength and good processability. SUMMARY

[0004] The present application aims to overcome the shortcomings of the prior art and provide a halogen-free flame-retardant polyphenyl ether composite material and a preparation method and application thereof. The material realizes excellent flame-retardant performance under thin-wall conditions by introducing an organic-inorganic composite flame retardant with a unique structure and the compounding and synergy of specific components.

[0005] To achieve the above-mentioned purpose, the first aspect of the present application provides a halogen-free flame-retardant polyphenyl ether composite material, which is composed of the following components in parts by mass: 40-70 parts of polyphenyl ether resin; 10-30 parts of high-impact polystyrene resin; 4-8 parts of SEBS resin; 5-10 parts of organic-inorganic composite flame retardant; 3-8 parts of phosphate ester flame retardant; 1-5 parts of polyborosiloxane; 0.5-2 parts of processing aid; The organic-inorganic composite flame retardant is a microparticle with a core-shell structure, in which magnesium-aluminum hydrotalcite and nano-silicon dioxide particles are used as the core and melamine cyanurate is used as the shell.

[0006] The performance meets the following indexes: (a) According to UL-94 standard test, 1.6mm and 0.8mm samples both reach V-0 level; (b) Limiting oxygen index (LOI) ≥ 33%; (c) Izod notched impact strength ≥ 14 kJ / m 2 .

[0007] Further, in the organic-inorganic composite flame retardant, the mass ratio of the magnesium-aluminum hydrotalcite to the nano-silica is 1:3-5, and the total mass ratio of the core to the shell is 1:15-30.

[0008] Further, the magnesium-aluminum hydrotalcite has a particle size less than 1000nm, and the chemical composition of the layer board is generally [Mg 2+ 1-x Al 3+ x (OH)2] x+ (A n- ) x / n ·mH2O, wherein A n- is CO3 2- , x is in the range of 0.25-0.33; and the nano-silica is fumed silica modified by silane coupling agent KH-550.

[0009] Further, the phosphate-based flame retardant is resorcinol bis(diphenyl phosphate) or bisphenol A bis(diphenyl phosphate).

[0010] Further, the polyborosiloxane has a number average molecular weight of 5000-20000g / mol, and the molecule side chain or terminal contains a hydroxyl or vinyl functional group.

[0011] Further, the processing aid is one or a combination of hindered phenol antioxidant, phosphite antioxidant, polytetrafluoroethylene, zinc stearate, and ethylene bis-stearamide.

[0012] The second application of the application provides a method for preparing the above halogen-free flame-retardant polyphenyl ether composite material, which comprises the following steps: S1. Preparing an organic-inorganic composite flame retardant: dispersing magnesium-aluminum hydrotalcite and nano-silica in deionized water, ultrasonic treatment to form a uniform suspension, adjusting pH to 3.0-4.0 by phosphoric acid; under 75-85℃ and intense stirring, slowly adding a supersaturated aqueous solution composed of melamine and cyanuric acid, and reacting for 6 hours to make melamine cyanurate crystallize and coat on the surface of the composite inorganic core in situ; after the reaction, filtering, washing, drying and crushing to obtain an organic-inorganic composite flame retardant with core-shell structure microparticles; S2. Pre-mixing: the polyphenyl ether resin, high-impact polystyrene resin, SEBS resin, organic-inorganic composite flame retardant obtained in step S1, phosphate ester flame retardant, polyborosiloxane, antioxidant and processing aid are placed in a high-speed mixer in proportion, mixed at 60-80 DEG C for 15 minutes to obtain a uniform pre-mixing material; S3. Melt blending and granulation: the pre-mixing material is fed into a double screw extruder, melt extruded, water tank cooled, air dried and granulated to obtain the halogen-free flame-retardant polyphenyl ether composite material; the processing temperature of the double screw extruder is set to 260 DEG C, and the screw rotation speed is 320 rpm.

[0013] Further, in step S1, the molar ratio of melamine to cyanuric acid is 1:0.98-1.02.

[0014] Further, in step S3, the screw configuration of the double screw extruder adopts a combined meshing block, at least one lateral vacuum exhaust port is provided between the melting section and the head, and the vacuum degree is controlled at -0.06 to -0.08 MPa.

[0015] The third aspect of the present application also provides a use of the above-mentioned halogen-free flame-retardant polyphenyl ether composite material in the preparation of thin-walled electronic and electrical shell or new energy automobile charging pile components.

[0016] The present application has the following advantages: The "magnesium-aluminum hydrotalcite-nano silicon dioxide@melamine cyanurate" core-shell structure innovatively introduced in the present application rapidly phase changes and decomposes the shell layer melamine cyanurate during combustion; in the core, the two-dimensional sheet-like nano structure of magnesium-aluminum hydrotalcite can form a dense and continuous "barrier type carbon layer" on the surface of the material during combustion, and the physical barrier effect is much better than that of amorphous nano silicon dioxide particles used alone. After the combination of the two, a multi-dimensional skeleton network can be formed during the combustion process, solving the problem of loose carbon layer.

[0017] At the same time, the polyborosiloxane can penetrate into the interior of the carbon layer and further form a solid, dense and continuous boron-silicon-carbon ceramicized carbon layer through hydroxyl dehydration crosslinking or vinyl crosslinking at high temperature. The carbon layer has excellent thermal stability and barrier property, and can effectively inhibit heat transfer, oxygen diffusion and combustible material overflow.

[0018] The dense ceramicized carbon layer greatly enhances the melt strength, fundamentally inhibiting the melt dripping phenomenon. The synergistic effect of polyborosiloxane and polytetrafluoroethylene further ensures the anti-dripping effect. DETAILED DESCRIPTION

[0020] It should be understood that, although the terms "first", "second" or the like can be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element without departing from the scope of the example embodiments. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0021] The present application provides a method for preparing halogen-free flame-retardant polyphenyl ether composite material, comprising the following steps: S1. Preparing organic-inorganic composite flame retardant: dispersing magnesium-aluminum hydrotalcite and nano-silica in deionized water, ultrasonic treatment to form a uniform suspension, adjusting pH to 3.0-4.0 with phosphoric acid; under 75-85℃ and vigorous stirring, slowly adding a supersaturated aqueous solution composed of melamine and cyanuric acid, and reacting for 6 hours to allow in-situ crystallization of melamine cyanurate on the surface of the composite inorganic core to form a coating; after the reaction is completed, filtering, washing, drying and crushing to obtain organic-inorganic composite flame retardant with core-shell structure, preferably the mass ratio of the magnesium-aluminum hydrotalcite to the nano-silica is 1:3-5, the total mass ratio of the core to the shell is 1:15-30, the particle size of the magnesium-aluminum hydrotalcite is less than 1000 nm, and the general chemical composition of the layer is [Mg 2+ 1- x Al 3+ x (OH)2] x+ (A n- ) x / n ·mH2O, wherein A n- is CO3 2- , x is in the range of 0.25-0.33; the nano-silica is fumed silica modified by silane coupling agent KH-550, and the molar ratio of the melamine to the cyanuric acid is 1:0.98-1.02; S2. Pre-mixing: placing polyphenyl ether resin, high-impact polystyrene resin, SEBS resin, organic-inorganic composite flame retardant obtained in step S1, phosphate ester flame retardant, polyborosiloxane, antioxidant and processing aid in a high-speed mixer in proportion, mixing at 60-80℃ for 15 minutes to obtain a uniform pre-mixture, preferably the phosphate ester flame retardant is resorcinol bis(diphenyl phosphate) or bisphenol A bis(diphenyl phosphate), the number average molecular weight of the polyborosiloxane is 5000-20000 g / mol, and the molecule side chain or terminal contains hydroxyl or vinyl functional groups, and the processing aid is one or a combination of hindered phenolic antioxidant, phosphite antioxidant, polytetrafluoroethylene, zinc stearate and ethylene bis-stearamide; S3. melt blending granulation: the premix is fed into a twin-screw extruder, melt extruded, water tank cooled, air dried, and granulated, to obtain the halogen-free flame-retardant polyphenylene ether composite; the processing temperature of the twin-screw extruder is set to 260℃, the screw rotation speed is 320 rpm, preferably the screw configuration of the twin-screw extruder adopts combined intermeshing blocks, at least one lateral vacuum exhaust port is arranged between the melt section and the die, and the vacuum degree is controlled at -0.06 ~ -0.08 MPa.

[0022] The application will be described in detail below through examples, but the protection scope of the application is not limited thereto.

[0023] Experimental materials: Polyphenylene ether resin (PPO): LXR40, China BlueStar Group.

[0024] High-impact polystyrene resin (HIPS): PS 454N, LyondellBasell Group.

[0025] SEBS resin: YH-503, SINOPEC Baling Petrochemical Co., Ltd.

[0026] Polyborosiloxane, magnesium-aluminum hydrotalcite (MgAl-LDH): self-made.

[0027] Nano-silicon dioxide: AEROSIL A200, Wacker Group, treated with KH-550.

[0028] Phosphate ester: resorcinol bis(diphenyl phosphate) (RDP), bisphenol A bis(diphenyl phosphate) (BDP), Zhejiang Wansheng Co., Ltd.

[0029] Antioxidant: antioxidant 1010, antioxidant 168, BASF.

[0030] Lubricant: zinc stearate, ethylene bis-stearamide, Clariant.

[0031] Polytetrafluoroethylene: Shanghai Jinwan Chemical Co., Ltd.

[0032] KH550, phosphoric acid, melamine and cyanuric acid are produced by National Pharmaceutical Reagent.

[0033] Performance test standards: Flame-retardant performance: UL-94 vertical burning, sample thickness 1.6 mm & 0.8 mm; LOI, tested according to ASTM D2863.

[0034] Impact strength: cantilever beam notched impact strength, tested according to national standard GB / T 1843-2008.

[0035] The formula components (mass parts) of examples 1~7 and comparative examples 1~6 are shown in table 1.

[0036] Table 1 Formulation components (parts by mass) of Examples 1-7 and Comparative Examples 1-6

[0037] The above halogen-free flame-retardant polyphenylene ether composite material is prepared by the following method: S1. Preparation of organic-inorganic composite flame retardant: disperse magnesium-aluminum hydrotalcite and nano-silica in deionized water, ultrasonic treatment to form a uniform suspension, adjust the pH to 3.0-4.0 with phosphoric acid; slowly add a supersaturated aqueous solution composed of melamine and cyanuric acid at 75-85°C with vigorous stirring, and react for 6 hours to allow in-situ crystallization of melamine cyanurate on the surface of the composite inorganic core; after the reaction is complete, filter, wash, dry, and crush to obtain core-shell structure particles; S2. Pre-mixing: place polyphenylene ether resin, high-impact polystyrene resin, SEBS resin, organic-inorganic composite flame retardant obtained in step S1, phosphate ester flame retardant, polyborosiloxane, antioxidant, and processing aid in a high-speed mixer in the proportions specified, mix at 60-80°C for 15 minutes to obtain a uniform pre-mix; S3. Melt blending and granulation: feed the pre-mix into a twin-screw extruder, melt extrude, water-cool, air-dry, and pelletize to obtain the halogen-free flame-retardant polyphenylene ether composite material; the processing temperature of the twin-screw extruder is set to 260°C, and the screw rotation speed is 320 rpm.

[0038] Example 1 The raw materials are weighed according to the data in Table 1 for “Example 1” and the halogen-free flame-retardant polyphenylene ether composite material is prepared, wherein the number average molecular weight of the polyborosiloxane is 15000 g / mol, and the molecule side chain or terminal contains a vinyl functional group; the particle size of the magnesium-aluminum hydrotalcite is 400-800 nm, and the general formula of the layer plate chemical composition is [Mg 2+ 1-x Al 3+ x (OH)2] x+ (A n- ) x / n ·mH2O, wherein A n- is CO3 2- , and x has a value of 0.25; the mass ratio of magnesium-aluminum hydrotalcite to nano-silica is 1:3; the mass ratio of core (magnesium-aluminum hydrotalcite and nano-silica) to shell (melamine cyanurate) is 1:19; the molar ratio of melamine to cyanuric acid during preparation of the core-shell structure is 1:1.02; and the vacuum degree of the lateral vacuum exhaust port during screw extrusion processing is controlled to -0.06 MPa.

[0039] Example 2 The raw materials were weighed according to the data of "Example 2" in Table 1, and the halogen-free flame-retardant polyphenylene ether composite was prepared, wherein the number average molecular weight of the polyborosiloxane was 10000 g / mol, the molecule side chain or terminal thereof contained a hydroxyl functional group; the particle size of the magnesium-aluminum hydrotalcite was 600-1000 nm, the general formula of the layer chemical composition thereof was [Mg 2+ 1-x Al 3+ x (OH)2] x+ (A n- ) x / n ·mH2O, wherein A n- is CO3 2- , and x was 0.33; the mass ratio of the magnesium-aluminum hydrotalcite to the nano-silica was 1:5; the total mass ratio of the core (the magnesium-aluminum hydrotalcite and the nano-silica) to the shell (melamine cyanurate) was 1:15; the molar ratio of melamine to cyanuric acid in the preparation of the core-shell structure was 1:0.98; and the vacuum degree of the lateral vacuum exhaust port in the screw extrusion process was controlled to be -0.08 MPa.

[0040] Example 3 The raw materials were weighed according to the data of "Example 3" in Table 1, and the halogen-free flame-retardant polyphenylene ether composite was prepared, wherein the number average molecular weight of the polyborosiloxane was 20000 g / mol, the molecule side chain or terminal thereof contained a hydroxyl functional group; the particle size of the magnesium-aluminum hydrotalcite was 400-800 nm, the general formula of the layer chemical composition thereof was [Mg 2+ 1-x Al 3+ x (OH)2] x+ (A n- ) x / n ·mH2O, wherein A n- is CO3 2- , and x was 0.30; the mass ratio of the magnesium-aluminum hydrotalcite to the nano-silica was 1:4; the mass ratio of the core (the magnesium-aluminum hydrotalcite and the nano-silica) to the shell (melamine cyanurate) was 1:17; the molar ratio of melamine to cyanuric acid in the preparation of the core-shell structure was 1:0.99; and the vacuum degree of the lateral vacuum exhaust port in the screw extrusion process was controlled to be -0.07 MPa.

[0041] Example 4 The raw materials were weighed according to the data of "Example 4" in Table 1, and the halogen-free flame-retardant polyphenylene ether composite was prepared, wherein the number average molecular weight of the polyborosiloxane was 8000 g / mol, the molecule side chain or terminal thereof contained a vinyl functional group; the particle size of the magnesium-aluminum hydrotalcite was 200-400 nm, the general formula of the layer chemical composition thereof was [Mg 2+ 1-x Al3+ x (OH)2] x+ (A n- ) x / n ·mH2O, wherein A n- is CO3 2- , x is 0.33; the mass ratio of magnesium-aluminum hydrotalcite to nano-silica is 1:3; the mass ratio of core (magnesium-aluminum hydrotalcite and nano-silica) to shell (melamine cyanurate) is 1:25; the molar ratio of melamine to cyanuric acid in the preparation of the core-shell structure is 1:1.02; the vacuum degree of the lateral vacuum exhaust port in the screw extrusion process is controlled at -0.08 MPa.

[0042] Example 5 The raw materials were weighed according to the data of "Example 5" in Table 1, and the halogen-free flame-retardant polyphenyl ether composite was prepared, wherein the number average molecular weight of the polysiloxane was 5000 g / mol, and the molecule side chain or terminal thereof contained a hydroxyl functional group; the particle size of the magnesium-aluminum hydrotalcite was 400-800 nm, and the general formula of the layer chemical composition thereof was [Mg 2+ 1-x Al 3+ x (OH)2] x+ (A n- ) x / n ·mH2O, wherein A n- is CO3 2- , x is 0.25; the mass ratio of magnesium-aluminum hydrotalcite to nano-silica is 1:4; the mass ratio of core (magnesium-aluminum hydrotalcite and nano-silica) to shell (melamine cyanurate) is 1:30; the molar ratio of melamine to cyanuric acid in the preparation of the core-shell structure is 1:0.99; the vacuum degree of the lateral vacuum exhaust port in the screw extrusion process is controlled at -0.06 MPa.

[0043] Example 6 The raw materials were weighed according to the data of "Example 6" in Table 1, and the halogen-free flame-retardant polyphenyl ether composite was prepared, wherein the number average molecular weight of the polysiloxane was 10000 g / mol, and the molecule side chain or terminal thereof contained a vinyl functional group; the particle size of the magnesium-aluminum hydrotalcite was 600-1000 nm, and the general formula of the layer chemical composition thereof was [Mg 2+ 1-x Al 3+ x (OH)2] x+ (A n- ) x / n ·mH2O, wherein A n- is CO3 2-, x is 0.33; the mass ratio of magnesium-aluminum hydrotalcite to nano-silica is 1:5; the mass ratio of core (magnesium-aluminum hydrotalcite and nano-silica) to shell (melamine cyanurate) is 1:23; the molar ratio of melamine to cyanuric acid in the preparation of the core-shell structure is 1:0.98; the vacuum degree of the lateral vacuum exhaust port in the screw extrusion process is controlled at -0.08 MPa.

[0044] Example 7 The raw materials were weighed according to the data of "Example 7" in Table 1 to prepare a halogen-free flame-retardant polyphenylene ether composite, wherein the number average molecular weight of the polysiloxane is 15000 g / mol, and the molecular side chain or terminal thereof contains a hydroxyl functional group; the particle size of the magnesium-aluminum hydrotalcite is 400-800 nm, and the general formula of the layer chemical composition thereof is [Mg 2+ 1-x Al 3+ x (OH)2] x+ A n- ) x / n ·mH2O, wherein A n- is CO3 2- , x is 0.33; the mass ratio of magnesium-aluminum hydrotalcite to nano-silica is 1:5; the mass ratio of core (magnesium-aluminum hydrotalcite and nano-silica) to shell (melamine cyanurate) is 1:23; the molar ratio of melamine to cyanuric acid in the preparation of the core-shell structure is 1:0.98; the vacuum degree of the lateral vacuum exhaust port in the screw extrusion process is controlled at -0.08 MPa.

[0045] Comparative Example 1 The formula composition of Comparative Example 1 is shown in Table 1, which is different from Example 1 in that no polysiloxane is added.

[0046] Comparative Example 2 The formula composition of Comparative Example 2 is shown in Table 1, which is different from Example 1 in that the organic-inorganic composite flame retardant is composed of magnesium-aluminum hydrotalcite@melamine cyanurate, and the particle size of the magnesium-aluminum hydrotalcite is 400-800 nm, and the general formula of the layer chemical composition thereof is [Mg 2+ 1-x Al 3+ x (OH)2] x+ (A n- ) x / n ·mH2O, wherein A n- is CO3 2- , x is 0.33; the mass ratio of magnesium-aluminum hydrotalcite to nano-silica is 1:5; the mass ratio of core (magnesium-aluminum hydrotalcite and nano-silica) to shell (melamine cyanurate) is 1:23; the molar ratio of melamine to cyanuric acid in the preparation of the core-shell structure is 1:0.98; the vacuum degree of the lateral vacuum exhaust port in the screw extrusion process is controlled at -0.08 MPa.

[0047] Comparative Example 3 The formulation composition of Comparative Example 3 is shown in Table 1, which is different from Example 1 in that the organic-inorganic composite flame retardant is composed of nano-silica@melamine cyanurate, the total mass ratio of core (nano-silica) to shell (melamine cyanurate) is 1:19, and the molar ratio of melamine to cyanuric acid in the preparation of the core-shell structure is 1:1.02.

[0048] Comparative Example 4 The formulation composition of Comparative Example 4 is shown in Table 1, which is different from Example 1 in that no organic-inorganic composite flame retardant is added, which is composed of 0.4 parts of magnesium-aluminum hydrotalcite and 7.6 parts of melamine cyanurate.

[0049] Comparative Example 5 The formulation composition of Comparative Example 5 is shown in Table 1, which is different from Example 1 in that no organic-inorganic composite flame retardant is added, which is composed of 0.4 parts of nano-silica and 7.6 parts of melamine cyanurate.

[0050] Comparative Example 6 The formulation composition of Comparative Example 6 is shown in Table 1, which is different from Example 1 in that no organic-inorganic composite flame retardant is added, which is composed of 0.1 parts of magnesium-aluminum hydrotalcite, 0.3 parts of nano-silica and 7.6 parts of melamine cyanurate.

[0051] The performance tests of the halogen-free flame-retardant polyphenyl ether composites prepared in Examples 1-7 and Comparative Examples 1-6 are carried out, and the results are shown in Table 2.

[0052] Table 2 Performance test results of the halogen-free flame-retardant polyphenyl ether composites prepared in Examples 1-7 and Comparative Examples 1-6

[0053] According to the data in Table 2, the halogen-free flame-retardant polyphenyl ether composites prepared in Examples 1-7 have excellent flame-retardant performance and impact performance. With the increase of the amount of HIPS resin and SEBS resin, the impact resistance of the material is significantly improved, although the LOI value decreases slightly, but due to the introduction of the core-shell structure organic-inorganic composite flame retardant, the agglomeration of nano-particles is effectively avoided, and the uniform dispersion of various flame-retardant components is realized, so that a good balance between various performances is achieved.

[0054] Comparative Example 1 does not add polysiloxane, and the 0.8mm sample only reaches UL-94 V-2 level, and the LOI value is also significantly low, indicating that polysiloxane has an irreplaceable key role in promoting the formation of a ceramic barrier layer and improving the flame-retardant performance of thin-walled materials.

[0055] In Comparative Examples 2 and 3, the inorganic core in the core-shell structure composite flame retardant is adjusted to a single component (single magnesium-aluminum hydrotalcite and single nano-silica, respectively), resulting in insufficient compactness and stability of the carbon layer structure formed after burning. Although V-0 level flame retardation can be achieved at a thickness of 1.6 mm, only V-1 level can be achieved at a thickness of 0.8 mm, which is difficult to meet the stringent requirements of high-end thin-wall applications.

[0056] In Comparative Examples 4 to 6, the components in the core-shell composite flame retardant are added in a physical mixing form. Due to poor dispersion uniformity and poor interfacial compatibility, not only is the flame retardation limited (only UL-94 V-1 level), but the impact strength also decreases significantly.

[0057] In summary, by optimizing the component composition and ratio, especially using an organic-inorganic composite flame retardant with a specific core-shell structure, and combining the synergistic effect of components such as polyborosiloxane, the present application successfully prepares a halogen-free flame-retardant polyphenyl ether composite material with excellent comprehensive performance. This material maintains high impact strength while achieving high flame retardation level under thin-wall conditions, and is completely suitable for thin-wall electronic and electrical enclosures and new energy vehicle components with stringent performance requirements.

[0058] The above-described examples only describe the preferred modes of the present application and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those of ordinary skill in the art should fall within the protection scope determined by the claims of the present application.

Claims

1. A halogen-free flame-retardant polyphenylene ether composite material, characterized in that, By weight, it consists of the following components: 40-70 parts of polyphenylene ether resin; 10-30 parts of high-impact polystyrene resin; 4-8 parts of SEBS resin; 5-10 parts of organic-inorganic composite flame retardant; 3-8 parts of phosphate ester flame retardant; 1-5 parts of polyborosiloxane; Processing aids: 0.5-2 parts; The organic-inorganic composite flame retardant is a core-shell structure of particles with magnesium aluminum hydrotalcite and nano-silica particles as the core and melamine cyanurate as the shell.

2. The halogen-free flame-retardant polyphenylene ether composite material according to claim 1, characterized in that, In the organic-inorganic composite flame retardant, the mass ratio of magnesium aluminum hydrotalcite to nano silica is 1:3~5, and the total mass ratio of the core to the shell is 1:15~30.

3. The halogen-free flame-retardant polyphenylene ether composite material according to claim 1, characterized in that, The magnesium-aluminum hydrotalcite has a particle size of less than 1000 nm, and the general chemical formula of the layer is [Mg 2+ 1-x Al 3+ x (OH)2] x+ (A n- ) x / n ·mH2O, where A n- CO3 2- The value of x ranges from 0.25 to 0.33; the nano-silica is fumed silica modified with silane coupling agent KH-550.

4. The halogen-free flame-retardant polyphenylene ether composite material according to claim 1, characterized in that, The phosphate ester flame retardant is resorcinol bis(diphenyl phosphate) or bisphenol A bis(diphenyl phosphate).

5. The halogen-free flame-retardant polyphenylene ether composite material according to claim 1, characterized in that, The polyborosiloxane has a number average molecular weight of 5000~20000 g / mol, and its molecular side chain or end contains hydroxyl or vinyl functional groups.

6. The halogen-free flame-retardant polyphenylene ether composite material according to claim 1, characterized in that, The processing aid is one or a combination of hindered phenolic antioxidants, phosphite antioxidants, polytetrafluoroethylene, zinc stearate, and ethylene bis-stearamide.

7. A method for preparing the halogen-free flame-retardant polyphenylene ether composite material as described in any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Preparation of organic-inorganic composite flame retardant: Magnesium aluminum hydrotalcite and nano-silica are dispersed in deionized water and ultrasonically treated to form a uniform suspension. The pH is adjusted to 3.0-4.0 with phosphoric acid. Under vigorous stirring at 75-85℃, a supersaturated aqueous solution composed of melamine and cyanuric acid is slowly added. The reaction is carried out for 6 hours to allow melamine cyanurate to crystallize and coat the surface of the composite inorganic core in situ. After the reaction is completed, the mixture is filtered, washed, dried and pulverized to obtain an organic-inorganic composite flame retardant with core-shell structured particles. S2. Premixing: Polyphenylene ether resin, high-impact polystyrene resin, SEBS resin, organic-inorganic composite flame retardant obtained in step S1, phosphate ester flame retardant, polyborosiloxane, antioxidant and processing aid are placed in a high-speed mixer in proportion and mixed at 60~80℃ for 15 minutes to obtain a uniform premix. S3. Melt blending and granulation: The premixed material is fed into a twin-screw extruder, melt-extruded, cooled in a water bath, air-dried, and granulated to obtain the halogen-free flame-retardant polyphenylene ether composite material; the processing temperature of the twin-screw extruder is set to 260℃ and the screw speed is 320rpm.

8. The method for preparing halogen-free flame-retardant polyphenylene ether composite material according to claim 7, characterized in that, In step S1, the molar ratio of melamine to cyanuric acid is 1:0.98~1.

02.

9. The method for preparing halogen-free flame-retardant polyphenylene ether composite material according to claim 7, characterized in that, In step S3, the screw configuration of the twin-screw extruder adopts a combined meshing block, and at least one lateral vacuum exhaust port is provided between the melting section and the die head, with the vacuum degree controlled at -0.06 ~ -0.08 MPa.

10. The application of a halogen-free flame-retardant polyphenylene ether composite material as described in any one of claims 1 to 6 in the preparation of thin-walled electronic and electrical housings or new energy vehicle charging pile components.

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