Heat-resistant flame-retardant modified PPE sheet and preparation method thereof

Abstract

The invention discloses a heat-resistant flame-retardant modified PPE sheet and a preparation method thereof, and relates to the field of polyphenyl ether-based composite materials. The heat-resistant flame-retardant modified PPE sheet is prepared from the following raw materials in parts by weight: 100 parts of polyphenyl ether resin, 15 to 20 parts of HIPS (High Impact Polystyrene) resin, 5.4 to 6.8 parts of styrene-glycidyl methacrylate, 10 to 20 parts of organic silicon modified elastomer, 25 to 30 parts of flame retardant and 1.5 to 2.5 parts of silicone master batch. The flame retardant is prepared from a silane coupling agent modified inorganic flame retardant and dihydroxy-methyl-ethyl silane-dimethoxy phosphonate according to the weight ratio of (1 to 3) to 1. The PPE sheet has the advantages of heat resistance, flame retardance and impact resistance.

Description

Technical Field

[0001] The present application relates to the field of polyphenylene ether-based composite materials, and in particular to a heat-resistant and flame-retardant modified PPE sheet and a preparation method thereof. Background Art

[0002] As a high-performance engineering plastic, polyphenylene ether (PPE) has been widely used in the fields of electronics, electrical engineering, and automotive industry due to its excellent heat resistance, chemical resistance, and mechanical properties.

[0003] Among them, adding flame retardants to polyphenylene ether can enhance its flame retardancy. Inorganic flame retardants are currently a commonly used flame retardant method due to their low cost and lack of harmful gas production. However, the dosage of inorganic flame retardants is large, and the addition of too much inorganic flame retardant can significantly reduce the impact resistance of polyphenylene ether. The addition of elastomers can improve the impact resistance of polyphenylene ether, but the addition of elastomers can also reduce the heat resistance of polyphenylene ether. Therefore, how to obtain a polyphenylene ether that combines heat resistance, flame retardancy, and impact resistance is currently an important research direction. Summary of the Invention

[0004] In order to improve the problem that it is difficult to obtain polyphenylene ether materials that are heat-resistant, flame-retardant and impact-resistant, the present application provides a heat-resistant and flame-retardant modified PPE sheet and a preparation method thereof.

[0005] In the first aspect, the present application provides a heat-resistant and flame-retardant modified PPE sheet adopting the following technical solution: A heat-resistant and flame-retardant modified PPE sheet is prepared from raw materials comprising 100 parts by weight of polyphenylene ether resin, 15-20 parts by weight of HIPS resin, 5.4-6.8 parts by weight of styrene-glycidyl methacrylate, 10-20 parts by weight of organosilicon-modified elastomer, 25-30 parts by weight of flame retardant, and 1.5-2.5 parts by weight of silicone masterbatch; the flame retardant comprises a silane coupling agent-modified inorganic flame retardant and dihydroxy-methyl-ethylsilane-dimethoxyphosphonate in a weight ratio of (1-3):1.

[0006] In this application, the heat-resistant and flame-retardant modified PPE sheet is made of a specific ratio of polyphenylene ether resin, HIPS resin, styrene-glycidyl methacrylate, silicone-modified elastomer, silane coupling agent-modified inorganic flame retardant, dihydroxy-methyl-ethylsilane-dimethoxyphosphonate and silicone masterbatch, and has the advantages of heat resistance, flame retardancy and impact resistance.

[0007] The flame retardant in this application utilizes a specifically formulated combination of a silane coupling agent-modified inorganic flame retardant and dihydroxy-methyl-ethylsilane-dimethoxyphosphonate. This combination reduces the amount of inorganic flame retardant used while imparting excellent flame retardancy to the polyphenylene ether. Furthermore, to compensate for the reduced impact resistance associated with the introduction of the silane coupling agent-modified inorganic flame retardant, this application incorporates a silicone-modified elastomer. Compared to directly adding unmodified elastomer to toughen the polyphenylene ether, the silicone-modified elastomer balances toughness with heat resistance, resulting in a polyphenylene ether sheet that combines heat resistance, flame retardancy, and impact resistance.

[0008] In addition, in order to address the problem of poor dispersibility caused by the high processing viscosity of polyphenylene ether and the poor compatibility between polyphenylene ether and other raw materials, the present application introduces styrene-methacrylate glycidyl ester and silicone masterbatch. Styrene-methacrylate glycidyl ester can react with the terminal hydroxyl groups of polyphenylene ether, the active reactive groups on the silane coupling agent-modified inorganic flame retardant, and the hydroxyl groups on dihydroxy-methyl-ethylsilane-dimethoxyphosphonate, thereby improving the compatibility of the silane coupling agent-modified inorganic flame retardant, dihydroxy-methyl-ethylsilane-dimethoxyphosphonate and polyphenylene ether. The silicone masterbatch has good melt fluidity at high temperature, which can improve the melt viscosity, improve the processing performance, and indirectly promote dispersion, thereby obtaining a polyphenylene ether sheet with stable performance.

[0009] In some preferred embodiments, the silicone-modified elastomer is prepared by reacting the epoxy group in the SEBS elastomer grafted with glycidyl methacrylate with the hydroxyl group in the vinyl-terminated and hydroxyl-terminated polydimethylsiloxane, and then performing a hydrosilylation reaction with the side hydrogen-containing silicone oil, wherein the weight ratio of the vinyl-terminated and hydroxyl-terminated polydimethylsiloxane, the SEBS elastomer grafted with glycidyl methacrylate, and the side hydrogen-containing silicone oil is (4.5-5.2):10:(5.5-6.5).

[0010] In the present application, the silicone-modified elastomer is prepared by reacting vinyl-terminated hydroxyl-terminated polydimethylsiloxane, glycidyl methacrylate grafted SEBS elastomer, and side hydrogen-containing silicone oil in a specific proportion. The silicone-modified elastomer has both toughness and better heat resistance, and can be evenly dispersed in the polyphenylene ether resin, which is beneficial to further improve the flame retardancy, heat resistance and impact resistance of the polyphenylene ether sheet.

[0011] In some specific embodiments, in the glycidyl methacrylate grafted SEBS elastomer, the grafting rate of glycidyl methacrylate is 5.5-6.5 wt %.

[0012] In some specific embodiments, the glycidyl methacrylate grafted SEBS elastomer has a melt index of 15-20 g / 10 min (230° C. / 5 kg).

[0013] In some specific embodiments, in the vinyl-terminated and hydroxyl-terminated polydimethylsiloxane, the polymerization degree of the dimethylsiloxane segment is 15-20.

[0014] In some specific embodiments, the structural formula of the side hydrogenated silicone oil is as follows: (CH3)3Si[O(CH3)2Si]m[O(H)(CH3)Si]OSi(CH3)3; wherein the value of m is 15-20.

[0015] In the present application, by controlling the appropriate grafting rate and melt index of the glycidyl methacrylate grafted SEBS elastomer, controlling the polymerization degree of the dimethylsiloxane segment in the vinyl-terminated hydroxyl-terminated polydimethylsiloxane, and controlling the polymerization degree of the dimethylsiloxane segment in the side hydrogen-containing silicone oil, it is beneficial to further improve the heat resistance of the polyphenylene ether sheet. At the same time, it further improves the uniform dispersion performance of the silicone-modified elastomer in the polyphenylene ether, which is beneficial to further improve the impact resistance of the polyphenylene ether sheet.

[0016] In some specific embodiments, the preparation method of the silicone modified elastomer includes the following steps: adding vinyl-terminated hydroxyl-terminated polydimethylsiloxane to glycidyl methacrylate grafted SEBS elastomer according to a ratio, then adding a tertiary amine catalyst, heating to 80-100°C after the reaction is completed, then adding side hydrogen-containing silicone oil and platinum catalyst to carry out a hydrosilylation reaction, and finally extruding and granulating to obtain the silicone modified elastomer.

[0017] In some specific embodiments, in the styrene-glycidyl methacrylate, the mass proportion of glycidyl methacrylate is 5.5-8.2%.

[0018] In the present application, the mass proportion of glycidyl methacrylate in styrene-glycidyl methacrylate is 5.5-8.2%, which is beneficial to further promote the uniform dispersion of various raw materials.

[0019] In some preferred embodiments, the weight ratio of the silane coupling agent modified inorganic flame retardant to dihydroxy-methyl-ethylsilane-dimethoxyphosphonate is (1.5-2):1.

[0020] In the present application, the weight ratio of the silane coupling agent modified inorganic flame retardant and dihydroxy-methyl-ethylsilane-dimethoxyphosphonate is controlled to (1.5-2):1, which is beneficial to further improve the flame retardant properties of the polyphenylene ether sheet.

[0021] In some specific embodiments, the silane coupling agent modified inorganic flame retardant is an aminosilane coupling agent modified inorganic flame retardant.

[0022] In the present application, the silane coupling agent-modified inorganic flame retardant uses an aminosilane coupling agent to modify the inorganic flame retardant, which is beneficial to promoting the uniform dispersion of the inorganic flame retardant in the polyphenylene ether.

[0023] In some specific embodiments, the inorganic flame retardant modified with an aminosilane coupling agent is at least one of aminosilane coupling agent-modified magnesium hydroxide and aminosilane coupling agent-modified aluminum hydroxide.

[0024] In a second aspect, the present application provides a method for preparing a heat-resistant and flame-retardant modified PPE sheet using the following technical solution: A method for preparing a heat-resistant and flame-retardant modified PPE sheet comprises the following steps: Polyphenylene ether resin, HIPS resin, styrene-glycidyl methacrylate, silicone modified elastomer, silane coupling agent modified inorganic flame retardant, dihydroxy-methyl-ethylsilane-dimethoxyphosphonate and silicone masterbatch are melt-mixed at 275-285° C., and then extruded and granulated to obtain modified polyphenylene ether masterbatch; The modified polyphenylene ether masterbatch is melted at 275-285° C. and then extruded, calendered and cooled to obtain a heat-resistant and flame-retardant modified PPE sheet.

[0025] In the present application, by combining various raw materials, the above-mentioned process with simple steps and convenient operation can be used to prepare polyphenylene ether sheets. At the same time, the raw materials can be evenly dispersed in the range of 275-285°C, which is conducive to obtaining polyphenylene ether sheets with stable performance.

[0026] In summary, this application has at least the following beneficial technical effects: (1) In the present application, the heat-resistant flame-retardant modified PPE sheet is made of a specific ratio of polyphenylene ether resin, HIPS resin, styrene-methyl glycidyl methacrylate, silicone-modified elastomer, silane coupling agent-modified inorganic flame retardant, dihydroxy-methyl-ethylsilane-dimethoxyphosphonate and silicone masterbatch, and has the advantages of heat resistance, flame retardancy and impact resistance.

[0027] (2) In the present application, the organosilicon-modified elastomer is prepared by reacting vinyl-terminated hydroxyl-terminated polydimethylsiloxane, glycidyl methacrylate grafted SEBS elastomer, and side hydrogen-containing silicone oil in a specific proportion. The organosilicon-modified elastomer has both toughness and better heat resistance, and can be uniformly dispersed in the polyphenylene ether resin, which is beneficial to further improve the flame retardancy, heat resistance and impact resistance of the polyphenylene ether sheet. DETAILED DESCRIPTION

[0028] The present application is further described below in conjunction with specific experiments.

[0029] Preparation Example [Preparation Example 1] A silicone modified elastomer comprising the following raw materials: 10 kg of glycidyl methacrylate-grafted SEBS elastomer; wherein the grafting rate of glycidyl methacrylate is 5.5 wt %, and the melt index of the glycidyl methacrylate-grafted SEBS elastomer is 18 g / 10 min (230°C / 5 kg); 4.5 kg of vinyl-terminated hydroxyl-terminated polydimethylsiloxane; wherein the degree of polymerization of the dimethylsiloxane segment in the vinyl-terminated hydroxyl-terminated polydimethylsiloxane is 15; Tertiary amine catalyst: 0.01 kg; wherein the tertiary amine catalyst is bisdimethylaminoethyl ether.

[0030] In this preparation example, the preparation method of the silicone modified elastomer is as follows: Add vinyl-terminated hydroxyl-terminated polydimethylsiloxane to glycidyl methacrylate grafted SEBS elastomer according to the ratio, then add tertiary amine catalyst, heat to 90°C and react for 20 minutes, then extrude and granulate to obtain silicone modified elastomer.

[0031] [Preparation Example 2] A silicone modified elastomer comprising the following raw materials: 10 kg of glycidyl methacrylate-grafted SEBS elastomer; wherein the grafting rate of glycidyl methacrylate is 5.5 wt %, and the melt index of the glycidyl methacrylate-grafted SEBS elastomer is 18 g / 10 min (230°C / 5 kg); 4.5 kg of vinyl-terminated hydroxyl-terminated polydimethylsiloxane; wherein the degree of polymerization of the dimethylsiloxane segment in the vinyl-terminated hydroxyl-terminated polydimethylsiloxane is 15; Tertiary amine catalyst: 0.01 kg; wherein the tertiary amine catalyst is bis(dimethylaminoethyl)ether; Bi-terminal hydrogen polydimethylsiloxane: 5.5 kg; wherein the degree of polymerization of the dimethylsiloxane segment in the bi-terminal hydrogen polydimethylsiloxane is 15; Platinum catalyst: 0.001 kg.

[0032] In this preparation example, the preparation method of the silicone modified elastomer is as follows: Vinyl-terminated and hydroxyl-terminated polydimethylsiloxane is added to glycidyl methacrylate-grafted SEBS elastomer according to the ratio, and then a tertiary amine catalyst is added. After heating to 90°C and reacting for 20 minutes, bi-hydrogen-terminated polydimethylsiloxane and platinum catalyst are added, and the reaction is continued for 20 minutes. Finally, the mixture is extruded and granulated to obtain a silicone-modified elastomer.

[0033] [Preparation Example 3] A silicone modified elastomer comprising the following raw materials: 10 kg of glycidyl methacrylate-grafted SEBS elastomer; wherein the grafting rate of glycidyl methacrylate is 5.5 wt %, and the melt index of the glycidyl methacrylate-grafted SEBS elastomer is 18 g / 10 min (230°C / 5 kg); 4.5 kg of vinyl-terminated hydroxyl-terminated polydimethylsiloxane; wherein the degree of polymerization of the dimethylsiloxane segment in the vinyl-terminated hydroxyl-terminated polydimethylsiloxane is 15; Tertiary amine catalyst: 0.01 kg; wherein the tertiary amine catalyst is bis(dimethylaminoethyl)ether; Side hydrogenated silicone oil: 5.5 kg; wherein, the structural formula of the side hydrogenated silicone oil is as follows: (CH3)3Si[O(CH3)2Si]m[O(H)(CH3)Si]OSi(CH3)3, where m is 15; Platinum catalyst: 0.001 kg.

[0034] In this preparation example, the preparation method of the silicone modified elastomer is as follows: Add vinyl-terminated and hydroxy-terminated polydimethylsiloxane to glycidyl methacrylate-grafted SEBS elastomer according to the ratio, then add tertiary amine catalyst, heat to 90°C and react for 20 minutes, then add side hydrogen-containing silicone oil and platinum catalyst, continue to react for 20 minutes, and finally extrude and granulate to obtain silicone-modified elastomer.

[0035] [Preparation Example 4] A silicone modified elastomer, which differs from [Preparation Example 3] in that the raw materials and proportions are different. In this preparation example, the raw materials used are as follows: 10 kg of glycidyl methacrylate-grafted SEBS elastomer; wherein the grafting rate of glycidyl methacrylate is 5.5 wt %, and the melt index of the glycidyl methacrylate-grafted SEBS elastomer is 18 g / 10 min (230°C / 5 kg); 5.2 kg of vinyl-terminated hydroxyl-terminated polydimethylsiloxane; wherein the degree of polymerization of the dimethylsiloxane segment in the vinyl-terminated hydroxyl-terminated polydimethylsiloxane is 20; Tertiary amine catalyst: 0.01 kg; wherein the tertiary amine catalyst is bis(dimethylaminoethyl)ether; Side hydrogenated silicone oil: 6.5 kg; wherein, the structural formula of the side hydrogenated silicone oil is as follows: (CH3)3Si[O(CH3)2Si]m[O(H)(CH3)Si]OSi(CH3)3, where m is 20; Platinum catalyst: 0.001 kg. Example

[0036] [Example 1] A heat-resistant and flame-retardant modified PPE sheet, comprising the following raw materials: Polyphenylene ether resin: 100kg; the polyphenylene ether resin is VESTORAN 1900GF20 from Evonik of Germany; HIPS resin: 15kg; HIPS resin uses Formosa Chemical HP825G; Styrene-glycidyl methacrylate: 6.8 kg; the mass proportion of glycidyl methacrylate in styrene-glycidyl methacrylate is 5.5%, and the weight-average molecular weight is 75,000-80,000; Organosilicon-modified elastomer: 10 kg; wherein the organosilicon-modified elastomer is the organosilicon-modified elastomer prepared in [Preparation Example 1]; Flame retardant: 25 kg; wherein the flame retardant includes aminosilane coupling agent KH550 modified aluminum hydroxide and dihydroxy-methyl-ethylsilane-dimethoxyphosphonate in a weight ratio of 1:1.

[0037] Silicone masterbatch: 1.5kg.

[0038] In this embodiment, the preparation method of the heat-resistant flame-retardant modified PPE sheet comprises the following steps: Polyphenylene ether resin, styrene-glycidyl methacrylate, organosilicon-modified elastomer, silane coupling agent-modified inorganic flame retardant, dihydroxy-methyl-ethylsilane-dimethoxyphosphonate and silicone masterbatch are melt-mixed and uniformly kneaded at 275° C., and then extruded and pelletized to obtain modified polyphenylene ether masterbatch; The modified polyphenylene ether masterbatch is melted at 275° C. and then extruded, calendered and cooled to obtain a heat-resistant and flame-retardant modified PPE sheet.

[0039] [Example 2] A heat-resistant and flame-retardant modified PPE sheet, comprising the following raw materials: Polyphenylene ether resin: 100kg; the polyphenylene ether resin is VESTORAN 1900GF20 from Evonik of Germany; HIPS resin: 20kg; HIPS resin uses Formosa Chemical HP825G; Styrene-glycidyl methacrylate: 5.4 kg; wherein the mass proportion of glycidyl methacrylate in styrene-glycidyl methacrylate is 8.2%, and the weight average molecular weight is 60,000-65,000.

[0040] Organosilicon-modified elastomer: 20 kg; wherein the organosilicon-modified elastomer is the organosilicon-modified elastomer prepared in [Preparation Example 1]; Flame retardant: 30 kg; wherein the flame retardant includes aminosilane coupling agent KH550 modified aluminum hydroxide and dihydroxy-methyl-ethylsilane-dimethoxyphosphonate in a weight ratio of 3:1.

[0041] Silicone masterbatch: 2.5kg.

[0042] In this embodiment, the preparation method of the heat-resistant flame-retardant modified PPE sheet comprises the following steps: Polyphenylene ether resin, styrene-glycidyl methacrylate, organosilicon-modified elastomer, silane coupling agent-modified inorganic flame retardant, dihydroxy-methyl-ethylsilane-dimethoxyphosphonate and silicone masterbatch are melt-mixed at 285° C., and then extruded and pelletized to obtain modified polyphenylene ether masterbatch; The modified polyphenylene ether masterbatch is melted at 285° C. and then extruded, calendered and cooled to obtain a heat-resistant and flame-retardant modified PPE sheet.

[0043] [Example 3] A heat-resistant and flame-retardant modified PPE sheet, which differs from [Example 1] in that the silicone-modified elastomer adopts the silicone-modified elastomer prepared in [Preparation Example 2].

[0044] [Example 4] A heat-resistant and flame-retardant modified PPE sheet, which differs from [Example 1] in that the silicone-modified elastomer adopts the silicone-modified elastomer prepared in [Preparation Example 3].

[0045] [Example 5] A heat-resistant and flame-retardant modified PPE sheet, which differs from [Example 1] in that the silicone-modified elastomer adopts the silicone-modified elastomer prepared in [Preparation Example 4].

[0046] Comparative Example [Comparative Example 1] A PPE sheet, which differs from [Example 1] in that styrene-glycidyl methacrylate is replaced by polyphenylene ether resin of equal mass.

[0047] [Comparative Example 2] A PPE sheet, which differs from [Example 1] in that the silicone-modified elastomer is replaced by an equal mass of glycidyl methacrylate-grafted SEBS elastomer.

[0048] [Comparative Example 3] A PPE sheet, which differs from [Example 1] in that dihydroxy-methyl-ethylsilane-dimethoxyphosphonate is replaced by a combination of (2-diethylphosphonoethyl)methyldiethoxysilane and ammonium polyphosphate, wherein the weight ratio of (2-diethylphosphonoethyl)methyldiethoxysilane to ammonium polyphosphate is 2:1.

[0049] Performance testing 1. Limiting Oxygen Index (LOI) test: Test according to ISO 4589-2, where a limiting oxygen index greater than 30% is considered qualified.

[0050] 2. Heat Deflection Temperature (HDT) Test: Tested in accordance with ISO 75-2 / B, under the condition of 0.45 MPa, without annealing. A heat deformation temperature greater than 190°C is considered acceptable.

[0051] 3. Charpy notched impact strength: tested according to ISO 179 / 1eA, test conditions are 0℃, complete fracture, among which, the Charpy notched impact strength is greater than 12KJ / m 2 To be qualified.

[0052] Table 1 Combining Example 1 with Comparative Example 1 and the data in Table 1, it can be seen that when the styrene-glycidyl methacrylate in the PPE sheet is replaced with an equal mass of polyphenylene ether resin, the limiting oxygen index, heat deformation temperature, and notched impact strength of the PPE sheet all decrease, indicating that the flame retardancy, heat resistance, and impact resistance of the PPE sheet are all reduced. Styrene-glycidyl methacrylate plays a key role in improving the uniform dispersion of raw materials such as flame retardants in polyphenylene ether resin, and the dispersion properties of the raw material directly affect the various properties of the PPE sheet.

[0053] Combining Example 1 with Comparative Example 2 and the data in Table 1, it can be seen that when the silicone-modified elastomer in the PPE sheet is replaced by an equal mass of glycidyl methacrylate-grafted SEBS elastomer, the limiting oxygen index and heat deformation temperature of the PPE sheet are significantly reduced. The reason is that the glycidyl methacrylate-grafted SEBS elastomer has not been modified with silicone and has poor flame retardancy and heat resistance.

[0054] Combining Example 1 with Comparative Example 3 and the data in Table 1, it can be seen that when the dihydroxy-methyl-ethylsilane-dimethoxyphosphonate in the PPE sheet is replaced by a composition of (2-diethylphosphonoethyl)methyldiethoxysilane and ammonium polyphosphate, the flame retardant properties of the PPE sheet are significantly reduced, indicating that dihydroxy-methyl-ethylsilane-dimethoxyphosphonate and a silane coupling agent-modified inorganic flame retardant are used together as flame retardants to achieve better flame retardant effects.

[0055] Combining Example 1 and Example 3 and the data in Table 1, it can be seen that when preparing the silicone-modified elastomer, adding a hydrosilylation reaction step can further improve the uniform dispersion performance of the silicone-modified elastomer in the polyphenylene ether resin, which is beneficial to further improve the flame retardant properties, heat resistance and impact resistance of the PPE sheet.

[0056] Combining Example 3 and Example 4 and the data in Table 1, it can be seen that when preparing the silicone-modified elastomer, the use of side hydrogen-containing silicone oil for hydrosilylation reaction is beneficial to further improve the uniform dispersion performance of the silicone-modified elastomer in the polyphenylene ether resin, which can further improve the flame retardant properties, heat resistance and impact resistance of the PPE sheet.

[0057] This specific implementation manner is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the specific implementation manner as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A heat-resistant and flame-retardant modified PPE sheet, characterized in that: The raw materials for preparing the heat-resistant and flame-retardant modified PPE sheet include 100 parts by weight of polyphenylene ether resin, 15-20 parts by weight of HIPS resin, 5.4-6.8 parts by weight of styrene-glycidyl methacrylate, 10-20 parts by weight of silicone-modified elastomer, 25-30 parts by weight of flame retardant and 1.5-2.5 parts by weight of silicone masterbatch; the flame retardant includes a silane coupling agent-modified inorganic flame retardant and dihydroxy-methyl-ethylsilane-dimethoxyphosphonate in a weight ratio of (1-3):

1.

2. The heat-resistant and flame-retardant modified PPE sheet according to claim 1, characterized in that: The organosilicon-modified elastomer is prepared by reacting the epoxy groups in the glycidyl methacrylate-grafted SEBS elastomer with the hydroxyl groups in the vinyl-terminated and hydroxyl-terminated polydimethylsiloxane, followed by a hydrosilylation reaction with a side hydrogenated silicone oil. The weight ratio of the vinyl-terminated and hydroxyl-terminated polydimethylsiloxane, the glycidyl methacrylate-grafted SEBS elastomer, and the side hydrogenated silicone oil is (4.5-5.2):10:(5.5-6.5).

3. The heat-resistant and flame-retardant modified PPE sheet according to claim 2, characterized in that: In the glycidyl methacrylate grafted SEBS elastomer, the grafting rate of glycidyl methacrylate is 5.5-6.5 wt %.

4. The heat-resistant and flame-retardant modified PPE sheet according to claim 2, characterized in that: The glycidyl methacrylate grafted SEBS elastomer has a melt index of 15-20 g / 10 min (230° C. / 5 kg).

5. The heat-resistant and flame-retardant modified PPE sheet according to claim 2, characterized in that: In the vinyl-terminated and hydroxyl-terminated polydimethylsiloxane, the polymerization degree of the dimethylsiloxane chain segment is 15-20.

6. A heat-resistant and flame-retardant modified PPE sheet according to any one of claims 2 to 5, characterized in that: The structural formula of the side hydrogen-containing silicone oil is as follows: (CH3)3Si[O(CH3)2Si]m[O(H)(CH3)Si]OSi(CH3)3; wherein the value of m is 15-20.

7. The heat-resistant and flame-retardant modified PPE sheet according to claim 1, characterized in that: In the styrene-glycidyl methacrylate, the mass proportion of glycidyl methacrylate is 5.5-8.2%.

8. The heat-resistant and flame-retardant modified PPE sheet according to claim 1, characterized in that: The weight ratio of the silane coupling agent modified inorganic flame retardant to dihydroxy-methyl-ethylsilane-dimethoxyphosphonate is (1.5-2):

1.

9. The heat-resistant and flame-retardant modified PPE sheet according to claim 1, characterized in that: The silane coupling agent modified inorganic flame retardant adopts an aminosilane coupling agent modified inorganic flame retardant.

10. A method for preparing a heat-resistant and flame-retardant modified PPE sheet according to any one of claims 1 to 9, characterized in that: The following steps are involved: Polyphenylene ether resin, HIPS resin, styrene-glycidyl methacrylate, silicone modified elastomer, silane coupling agent modified inorganic flame retardant, dihydroxy-methyl-ethylsilane-dimethoxyphosphonate and silicone masterbatch are melt-mixed at 275-285° C., and then extruded and granulated to obtain modified polyphenylene ether masterbatch; The modified polyphenylene ether masterbatch is melted at 275-285° C. and then extruded, calendered and cooled to obtain a heat-resistant and flame-retardant modified PPE sheet.

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