Low-dielectric polyphenyl ether foaming material and preparation process thereof

Abstract

The invention discloses a low-dielectric polyphenyl ether foaming material and a preparation process thereof, and relates to the technical field of foaming material preparation. Comprising the following raw materials: polyphenyl ether, modified polystyrene, modified polymethylpentene, silane modified hollow carbon microspheres, nano silicon dioxide, an antioxidant, a styrene-ethylene / butylene-styrene star block copolymer and a fluorine processing aid. The modified polymethylpentene is added, so that the dielectric constant and dielectric loss of the foaming material can be remarkably reduced, the high-frequency insulating property of the material can be enhanced, the heat resistance and dimensional stability of a system can be improved, the compression set of the material is reduced, and the deformation resistance is enhanced; the modified polystyrene, the polyphenyl ether and the silane modified hollow carbon microspheres have excellent synergistic adaptability, and endow the material with the comprehensive characteristics of lower dielectric, higher heat resistance and better toughness on the premise of not damaging the bubble pore structure.

Description

Technical Field

[0001] This invention relates to the field of foam material preparation technology, and in particular to a low-dielectric polyphenylene ether foam material and its preparation process. Background Technology

[0002] Foamed materials are a class of lightweight, porous materials filled with numerous air bubbles. They are typically formed by introducing air bubbles into a matrix such as plastic, rubber, metal, or ceramic through physical or chemical methods. Due to their excellent properties such as light weight, heat insulation, sound absorption, and cushioning, these materials are widely used in various fields including packaging insulation, building materials, automobiles and ships, sporting goods, and everyday consumer products.

[0003] Traditional low-dielectric polyphenylene ether foam materials generally suffer from high brittleness, weak impact resistance, and susceptibility to cracking and breakage during use. They also exhibit high dielectric constants and dielectric losses, failing to meet the requirements for high-frequency insulation. Furthermore, they suffer from poor heat resistance and dimensional stability, easily deforming under heat and pressure. In addition, filler agglomeration and poor bonding with the matrix lead to low closed-cell ratio, high density, and uneven cell structure. Therefore, this invention provides a low-dielectric polyphenylene ether foam material and its preparation process. Summary of the Invention

[0004] The main objective of this invention is to provide a low-dielectric polyphenylene ether foam material with low dielectric constant and high closed-cell ratio, and its preparation process, which is applied to a low-dielectric polyphenylene ether foam material and its preparation process.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides a low-dielectric polyphenylene ether foam material, which comprises the following raw materials in parts by weight: 40-48 parts polyphenylene ether, 20-24 parts modified polystyrene, 8-12 parts modified polymethylpentene, 11-13 parts silane-modified hollow carbon microspheres, 1.4-1.6 parts nano-silica, 0.4-0.6 parts antioxidant, 4-6 parts styrene-ethylene / butene-styrene star-shaped block copolymer, and 0.9-1.1 parts fluorine processing aids.

[0006] Polyphenylene oxide (PPE) has a melt index of 2-5 g / 10 min, a heat distortion temperature of ≥130℃, a dielectric constant of 2.4-2.6, a moisture content of ≤0.1%, and a tensile strength of ≥60 MPa. It possesses basic performance parameters such as high temperature resistance, low dielectric, and high strength, making it a core matrix raw material for foamed materials.

[0007] Nano-silica is hydrophobic, with a particle size of 15nm, a specific surface area of ​​150-200m² / g, a water content of ≤0.5%, a contact angle of ≥100° after hydrophobic modification, and a purity of ≥99%. It effectively refines the foaming pores, improves the closed-cell rate, enhances the structural strength of the pore walls, and prevents pore collapse and rupture. At the same time, it can improve the dimensional stability and mechanical properties of the material without negatively affecting the low dielectric properties.

[0008] The styrene-ethylene / butene-styrene star block copolymer has a styrene content of 30-35%, a melt index of 1-8 g / 10 min, a Shore hardness of 60-70 A, a dielectric constant of 2.2-2.4, and a tensile strength of ≥10 MPa. It can further eliminate the brittleness of foamed materials, improve the bending performance and impact resistance of materials, and make materials less prone to breakage.

[0009] Fluorine processing aids have a particle size of 1-10 μm, a melting point of 320-340℃, a dielectric constant of ≤1.9, and a moisture content of ≤0.1%. They can reduce interfacial polarization between the resin matrix and the filler, further reduce dielectric loss, and improve the processing fluidity of the melt, thus avoiding problems such as sticking to the mold and uneven flow during extrusion.

[0010] Furthermore, the antioxidant is composed of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl)phosphite in a mass ratio of 1:1.

[0011] Furthermore, the fluorine-based processing aid is one of polytetrafluoroethylene micro powder and vinylidene fluoride-hexafluoropropylene copolymer micro powder.

[0012] Furthermore, the preparation of the modified polystyrene includes the following steps: A1. Vacuum dry polystyrene at a set temperature of 80℃ and a vacuum degree of -0.095MPa for 4 hours to obtain dried polystyrene; A2. Dry polystyrene, 5-fluorobicyclo[2.2.1]heptene, 1-vinyladamantane, di-tert-amyl peroxide, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and tris(2,4-di-tert-butylphenyl) phosphite were mixed and stirred at 800 rpm for 3 minutes to obtain a mixture. A3. The mixture is fed into a twin-screw extruder. The temperatures of each section of the extruder are set sequentially to 220℃, 230℃, 240℃, 245℃, 245℃, and 240℃. The screw speed is controlled at 220 rpm and the vacuum degree is -0.08 MPa. The extruded material is obtained. After the extruded material is granulated, it is placed in a drying oven for drying at 80℃ for 4 hours to obtain modified polystyrene.

[0013] Further, the mass ratio of the dried polystyrene, 5-fluorobicyclo[2.2.1]heptene, 1-vinyladamantane, di-tert-amyl peroxide, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl)phosphite is 100:1.25:0.8:0.08:0.05:0.05.

[0014] Furthermore, the preparation of the modified polymethylpentene includes the following steps: B1. Vacuum dry polymethylpentene at a set temperature of 80℃ and a vacuum degree of -0.095MPa for 4 hours to obtain dried polymethylpentene; B2. Dry polymethylpentene, perfluorononenyl succinimide, vinyl norbornene, di-tert-pentyl peroxide, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl) phosphite are mixed and stirred at 800 rpm for 3 minutes to obtain material A; B3. Material A is placed into a twin-screw extruder. The temperatures of each section of the extruder are set sequentially to 260℃, 270℃, 280℃, 285℃, 280℃, and 275℃. The screw speed is controlled at 220 rpm and the vacuum degree is -0.08 MPa to obtain material B. Material B is granulated and placed in a drying oven for drying. The temperature is set at 80℃ and the drying time is 4 hours to obtain modified polymethylpentene.

[0015] Furthermore, the mass ratio of the dried polymethylpentene, perfluorononenyl succinimide, vinyl norbornene, di-tert-pentyl peroxide, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl) phosphite is 100:1.5:1:0.08:0.05:0.05.

[0016] Furthermore, the preparation of the silane-modified hollow carbon microspheres includes the following steps: C1. Place the hollow carbon microspheres in a vacuum drying oven and dry them at a temperature of 120℃ and a vacuum of -0.095MPa for 6 hours to obtain dried hollow carbon microspheres. C2. Mix anhydrous ethanol, perfluorooctyltriethoxysilane, vinyltrimethoxysilane and hydrochloric acid, set the speed to 300 rpm and stir for 30 minutes to obtain the modifier; C3. Add the modifier and dried hollow carbon microspheres to the reactor and ultrasonically disperse them. Set the power to 180W and ultrasonically disperse for 30 minutes. Heat the reactor to 60℃ and stir. Set the speed to 200rpm and stir for 2 hours. Filter and collect the filter cake. Wash the filter cake three times with anhydrous ethanol. Place the washed filter cake in an oven to dry. Set the temperature to 100℃ and dry for 6 hours to obtain silane-modified hollow carbon microspheres.

[0017] The hollow carbon microspheres have a particle size D50 of 1-5 micrometers and a true density of 0.4-0.6 g / cm³.

[0018] Furthermore, hydrochloric acid is added to C2 to adjust the pH to 4-5; The mass ratio of anhydrous ethanol, perfluorooctyltriethoxysilane, and vinyltrimethoxysilane in C2 is 1000:6.5:4; The mass ratio of the modifier to the dried hollow carbon microspheres in C3 is 10:1.

[0019] Secondly, the present invention provides a preparation process for a low-dielectric polyphenylene ether foam material, the preparation process of which includes the following steps: S1. Polyphenylene ether, modified polystyrene, and modified polymethylpentene were placed in a vacuum drying oven and dried at a vacuum degree of -0.095 MPa and a temperature of 80°C for 4 hours. Silane-modified hollow carbon microspheres and nano-silica were placed in another vacuum drying oven and dried at a vacuum degree of -0.095 MPa and a temperature of 120°C for 6 hours. The dried polyphenylene ether, modified polystyrene, modified polymethylpentene, silane-modified hollow carbon microspheres, and nano-silica were placed in a reaction vessel. Antioxidant, styrene-ethylene / butene-styrene star-shaped block copolymer, and fluorine processing aids were added and mixed. The mixture was stirred at a speed of 900 rpm for 3 minutes to obtain material D. S2. Material D is fed into a twin-screw extruder and extruded. The temperatures of each section of the extruder are set sequentially to 250℃, 265℃, 275℃, 280℃, 280℃, 275℃, and 270℃. The screw speed is controlled at 220 rpm and the vacuum degree is -0.08 MPa. Material E is obtained by extrusion. Material E is granulated and dried. The temperature is set at 80℃ and the drying time is 4 hours to obtain composite foamed granules. S3. Place the composite foamed granules into the foaming machine, set the temperature of the foaming machine feed section to the mold front to be 245℃, 255℃, 260℃, and 255℃ respectively, inject supercritical CO2 at an injection pressure of 15MPa, and inject 2-3% of the mass of the composite foamed granules. Set the foaming machine screw speed to 210rpm, the mold front temperature to 240℃, the mold front pressure to 12MPa, the mold opening to 0.8-1.2mm, and the traction speed to 2.5-3.5m / min. Demold the material to obtain low-dielectric polyphenylene ether foamed material.

[0020] The present invention has the following beneficial effects: 1. In this invention, modified polystyrene is added, which can form a good compatibility with the polyphenylene ether matrix, fundamentally improving the problem of brittleness and easy breakage of foamed materials, greatly improving the toughness and impact resistance of the materials, while reducing the dielectric constant and dielectric loss of the system, optimizing melt processing fluidity, making the foaming process more stable, and also improving the closed-cell rate of the foamed material, making the cell structure finer and more uniform. While ensuring the low dielectric properties of the material, mechanical properties and foaming molding quality are also taken into account.

[0021] 2. In this invention, modified polymethylpentene is added, which can significantly reduce the dielectric constant and dielectric loss of the foamed material, enhance the high-frequency insulation performance of the material, improve the heat resistance and dimensional stability of the system, reduce the compression set of the material, and enhance the resistance to deformation. It has excellent synergistic compatibility with modified polystyrene, polyphenylene ether and silane-modified hollow carbon microspheres, and endows the material with comprehensive properties of lower dielectric, higher heat resistance and better toughness without destroying the foamed cell structure.

[0022] 3. In this invention, silane-modified hollow carbon microspheres are added. Their surface has hydrophobic and moisture-proof properties. They are uniformly dispersed in the resin matrix and have a tight interfacial bond, without the problems of agglomeration or debonding. They can be used as a highly efficient nucleating agent to improve the foaming nucleation efficiency, resulting in higher closed-cell rate and lower density of the foamed material, achieving a lightweight effect. At the same time, they can significantly reduce the dielectric constant of the material and reduce the loss caused by interfacial polarization, thus improving the comprehensive performance of the foamed material from both structural and functional aspects. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] It should be noted that all raw materials used in the following experiments are commercially available.

[0025] The preparation methods of modified polystyrene, modified polymethylpentene, and silane-modified hollow carbon microspheres in the following embodiments and comparative examples of the present invention are shown below. I. Preparation of Modified Polystyrene A1. Vacuum dry polystyrene at a set temperature of 80℃ and a vacuum degree of -0.095MPa for 4 hours to obtain dried polystyrene; A2. Mix 100 parts of dry polystyrene, 1.25 parts of 5-fluorobicyclo[2.2.1]heptene, 0.8 parts of 1-vinyladamantane, 0.08 parts of di-tert-amyl peroxide, 0.05 parts of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and 0.05 parts of tris(2,4-di-tert-butylphenyl) phosphite. Set the speed to 800 rpm and stir for 3 minutes to obtain a mixture. A3. The mixture is fed into a twin-screw extruder. The temperatures of each section of the extruder are set sequentially to 220℃, 230℃, 240℃, 245℃, 245℃, and 240℃. The screw speed is controlled at 220 rpm and the vacuum degree is -0.08 MPa. The extruded material is obtained. After the extruded material is granulated, it is placed in a drying oven for drying at 80℃ for 4 hours to obtain modified polystyrene.

[0026] II. Preparation of Modified Polymethylpentene B1. Vacuum dry polymethylpentene at a set temperature of 80℃ and a vacuum degree of -0.095MPa for 4 hours to obtain dried polymethylpentene; B2. Mix 100 parts of dried polymethylpentene, 1.5 parts of perfluorononenyl succinimide, 1 part of vinyl norbornene, 0.08 parts of di-tert-amyl peroxide, 0.05 parts of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and 0.05 parts of tris(2,4-di-tert-butylphenyl) phosphite and stir at 800 rpm for 3 minutes to obtain material A; B3. Material A is placed into a twin-screw extruder. The temperatures of each section of the extruder are set sequentially to 260℃, 270℃, 280℃, 285℃, 280℃, and 275℃. The screw speed is controlled at 220 rpm and the vacuum degree is -0.08 MPa to obtain material B. Material B is granulated and placed in a drying oven for drying. The temperature is set at 80℃ and the drying time is 4 hours to obtain modified polymethylpentene.

[0027] III. Preparation of Silane-Modified Hollow Carbon Microspheres C1. Place the hollow carbon microspheres in a vacuum drying oven and dry them at a temperature of 120℃ and a vacuum of -0.095MPa for 6 hours to obtain dried hollow carbon microspheres. C2. Mix 1000 parts of anhydrous ethanol, 6.5 parts of perfluorooctyltriethoxysilane, 4 parts of vinyltrimethoxysilane and hydrochloric acid, set the speed to 300 rpm, and stir for 30 minutes to obtain the modifier; C3. Add 10 parts of modifier and 1 part of dried hollow carbon microspheres to a reactor and ultrasonically disperse them. Set the power to 180W and ultrasonically disperse for 30 minutes. Heat the reactor to 60℃ and stir. Set the speed to 200rpm and stir for 2 hours. Filter and collect the filter cake. Wash the filter cake three times with anhydrous ethanol. Place the washed filter cake in an oven to dry. Set the temperature to 100℃ and dry for 6 hours to obtain silane-modified hollow carbon microspheres.

[0028] Add hydrochloric acid to adjust the pH to 4.5.

[0029] Example 1: A low-dielectric polyphenylene ether foam material, comprising the following raw materials in parts by weight: 40 parts polyphenylene ether, 20 parts modified polystyrene, 8 parts modified polymethylpentene, 11 parts silane-modified hollow carbon microspheres, 1.4 parts nano-silica, 0.4 parts antioxidant, 4 parts styrene-ethylene / butene-styrene star-shaped block copolymer, and 0.9 parts fluorine processing aids.

[0030] The antioxidant is a mixture of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl)phosphite in a mass ratio of 1:1.

[0031] Fluorine-based processing aids are polytetrafluoroethylene micro powders.

[0032] A preparation process for a low-dielectric polyphenylene ether foam material includes the following steps: S1. Polyphenylene ether, modified polystyrene, and modified polymethylpentene were placed in a vacuum drying oven and dried at a vacuum degree of -0.095 MPa and a temperature of 80°C for 4 hours. Silane-modified hollow carbon microspheres and nano-silica were placed in another vacuum drying oven and dried at a vacuum degree of -0.095 MPa and a temperature of 120°C for 6 hours. The dried polyphenylene ether, modified polystyrene, modified polymethylpentene, silane-modified hollow carbon microspheres, and nano-silica were placed in a reaction vessel. Antioxidant, styrene-ethylene / butene-styrene star-shaped block copolymer, and fluorine processing aids were added and mixed. The mixture was stirred at a speed of 900 rpm for 3 minutes to obtain material D. S2. Material D is fed into a twin-screw extruder and extruded. The temperatures of each section of the extruder are set sequentially to 250℃, 265℃, 275℃, 280℃, 280℃, 275℃, and 270℃. The screw speed is controlled at 220 rpm and the vacuum degree is -0.08 MPa. Material E is obtained by extrusion. Material E is granulated and dried. The temperature is set at 80℃ and the drying time is 4 hours to obtain composite foamed granules. S3. Place the composite foamed granules into the foaming machine, set the temperature of the foaming machine feed section to the mold front to be 245℃, 255℃, 260℃, and 255℃ respectively, inject supercritical CO2 at an injection pressure of 15MPa, and inject 2% of the mass of the composite foamed granules. Set the screw speed of the foaming machine to 210rpm, the mold front temperature to 240℃, the mold front pressure to 12MPa, the mold opening to 0.8mm, and the traction speed to 2.5m / min. Demold the material to obtain low-dielectric polyphenylene ether foamed material.

[0033] Example 2: A low-dielectric polyphenylene ether foam material, comprising the following raw materials in parts by weight: 44 parts polyphenylene ether, 22 parts modified polystyrene, 10 parts modified polymethylpentene, 12 parts silane-modified hollow carbon microspheres, 1.5 parts nano-silica, 0.5 parts antioxidant, 5 parts styrene-ethylene / butene-styrene star-shaped block copolymer, and 1 part fluorine processing aid.

[0034] The antioxidant is a mixture of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl)phosphite in a mass ratio of 1:1.

[0035] The fluorine-based processing aid is a micro powder of vinylidene fluoride-hexafluoropropylene copolymer.

[0036] A preparation process for a low-dielectric polyphenylene ether foam material includes the following steps: S1. Polyphenylene ether, modified polystyrene, and modified polymethylpentene were placed in a vacuum drying oven and dried at a vacuum degree of -0.095 MPa and a temperature of 80°C for 4 hours. Silane-modified hollow carbon microspheres and nano-silica were placed in another vacuum drying oven and dried at a vacuum degree of -0.095 MPa and a temperature of 120°C for 6 hours. The dried polyphenylene ether, modified polystyrene, modified polymethylpentene, silane-modified hollow carbon microspheres, and nano-silica were placed in a reaction vessel. Antioxidant, styrene-ethylene / butene-styrene star-shaped block copolymer, and fluorine processing aids were added and mixed. The mixture was stirred at a speed of 900 rpm for 3 minutes to obtain material D. S2. Material D is fed into a twin-screw extruder and extruded. The temperatures of each section of the extruder are set sequentially to 250℃, 265℃, 275℃, 280℃, 280℃, 275℃, and 270℃. The screw speed is controlled at 220 rpm and the vacuum degree is -0.08 MPa. Material E is obtained by extrusion. Material E is granulated and dried. The temperature is set at 80℃ and the drying time is 4 hours to obtain composite foamed granules. S3. Place the composite foamed granules into the foaming machine, set the temperature of the foaming machine feed section to the mold front to be 245℃, 255℃, 260℃, and 255℃ respectively, inject supercritical CO2 at an injection pressure of 15MPa, and inject 2.5% of the mass of the composite foamed granules. Set the screw speed of the foaming machine to 210rpm, the mold front temperature to 240℃, the mold front pressure to 12MPa, the mold opening to 1mm, and the traction speed to 3m / min. Demold the material to obtain low-dielectric polyphenylene ether foamed material.

[0037] Example 3: A low-dielectric polyphenylene ether foam material, comprising the following raw materials in parts by weight: 48 parts polyphenylene ether, 24 parts modified polystyrene, 12 parts modified polymethylpentene, 13 parts silane-modified hollow carbon microspheres, 1.6 parts nano-silica, 0.6 parts antioxidant, 6 parts styrene-ethylene / butene-styrene star-shaped block copolymer, and 1.1 parts fluorine processing aids.

[0038] The antioxidant is a mixture of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl)phosphite in a mass ratio of 1:1.

[0039] Fluorine-based processing aids are polytetrafluoroethylene micro powders.

[0040] A preparation process for a low-dielectric polyphenylene ether foam material includes the following steps: S1. Polyphenylene ether, modified polystyrene, and modified polymethylpentene were placed in a vacuum drying oven and dried at a vacuum degree of -0.095 MPa and a temperature of 80°C for 4 hours. Silane-modified hollow carbon microspheres and nano-silica were placed in another vacuum drying oven and dried at a vacuum degree of -0.095 MPa and a temperature of 120°C for 6 hours. The dried polyphenylene ether, modified polystyrene, modified polymethylpentene, silane-modified hollow carbon microspheres, and nano-silica were placed in a reaction vessel. Antioxidant, styrene-ethylene / butene-styrene star-shaped block copolymer, and fluorine processing aids were added and mixed. The mixture was stirred at a speed of 900 rpm for 3 minutes to obtain material D. S2. Material D is fed into a twin-screw extruder and extruded. The temperatures of each section of the extruder are set sequentially to 250℃, 265℃, 275℃, 280℃, 280℃, 275℃, and 270℃. The screw speed is controlled at 220 rpm and the vacuum degree is -0.08 MPa. Material E is obtained by extrusion. Material E is granulated and dried. The temperature is set at 80℃ and the drying time is 4 hours to obtain composite foamed granules. S3. Place the composite foamed granules into the foaming machine, set the temperature of the foaming machine feed section to the mold front to be 245℃, 255℃, 260℃, and 255℃ respectively, inject supercritical CO2 at an injection pressure of 15MPa, and inject 3% of the mass of the composite foamed granules. Set the screw speed of the foaming machine to 210rpm, the mold front temperature to 240℃, the mold front pressure to 12MPa, the mold opening to 1.2mm, and the traction speed to 3.5m / min. Demold the material to obtain low-dielectric polyphenylene ether foamed material.

[0041] Comparative Example 1: The difference between this comparative example and Example 1 is that: Unmodified polystyrene was used in this comparative example.

[0042] Comparative Example 2: The difference between this comparative example and Example 1 is that: Unmodified polymethylpentene was used in this comparative example.

[0043] Comparative Example 3: The difference between this comparative example and Example 1 is that: This comparative example uses unmodified silane-free hollow carbon microspheres.

[0044] Performance testing: The low dielectric polyphenylene ether foam material prepared in Examples 1, 2, 3, Comparative Examples 1, 2, and 3 and its preparation process were tested.

[0045] Performance testing: The relevant properties of the low-dielectric polyphenylene ether foam materials and their preparation processes provided in Examples 1-3 and Comparative Examples 1-3 were tested respectively, and the test data are recorded in Table 1 below: Table 1 - Performance Testing of Low Dielectric Polyphenylene Ether Foamed Materials

[0046] Based on the above data, the following conclusions can be drawn: Among them, the dielectric constant of a low dielectric polyphenylene ether foam material prepared using the test methods in GB / T1409-2006 in Examples 1, 2, 3, Comparative Examples 1, 2, and 3 is tested. Compression set test of a low dielectric polyphenylene ether foam material prepared according to the test methods in GB / T20467-2006 in Examples 1, 2, 3, Comparative Examples 1, 2, and 3; at 70℃ / 22h. A test of the closed-cell rate of a low-dielectric polyphenylene ether foam material prepared according to the test methods in GB / T10799-2008 (Examples 1, 2, 3, Comparative Examples 1, 2, and 3).

[0047] Silane-modified hollow carbon microspheres, after surface modification, bond more tightly to the resin matrix and disperse more uniformly. They can act as efficient nucleating agents to guide the uniform and refined formation of foam cells, directly reducing the apparent density of the foamed material and improving the closed-cell ratio test value. At the same time, they reduce interfacial polarization and moisture absorption within the material, thereby reducing the dielectric constant and dielectric loss. Modified polymethylpentene, with its low dielectric and high heat resistance properties, is compatible with all components of the foaming system. It can directly lower the dielectric constant and dielectric loss test values ​​of the foamed material, while increasing the heat distortion temperature, enhancing the elasticity and deformation resistance of the material, and reducing compression set. Modified polystyrene has excellent compatibility with the main resin, effectively improving the problem of high brittleness in foamed materials, significantly improving impact strength test data, and optimizing melt processing fluidity, resulting in a finer and more uniform distribution of foam cells and improving the closed-cell ratio.

[0048] Based on the above demonstrations, the present invention is significantly superior to the comparative group in terms of dielectric constant, 70℃ / 22h compression set, and closed-cell ratio.

[0049] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0050] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A low-dielectric polyphenylene ether foam material, characterized in that, The low-dielectric polyphenylene ether foam material comprises the following raw materials in parts by weight: 40-48 parts polyphenylene ether, 20-24 parts modified polystyrene, 8-12 parts modified polymethylpentene, 11-13 parts silane-modified hollow carbon microspheres, 1.4-1.6 parts nano-silica, 0.4-0.6 parts antioxidant, 4-6 parts styrene-ethylene / butene-styrene star-shaped block copolymer, and 0.9-1.1 parts fluorine processing aids; The modified polystyrene is obtained by mixing and stirring dried polystyrene, 5-fluorobicyclo[2.2.1]heptene, 1-vinyladamantane, di-tert-amyl peroxide, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl) phosphite. The modified polymethylpentene is obtained by mixing and stirring dried polymethylpentene, perfluorononenyl succinimide, vinyl norbornene, di-tert-pentyl peroxide, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl) phosphite.

2. The low-dielectric polyphenylene ether foam material according to claim 1, characterized in that, The antioxidant is composed of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl)phosphite in a mass ratio of 1:

1.

3. The low-dielectric polyphenylene ether foam material according to claim 1, characterized in that, The fluorine-based processing aid is one of polytetrafluoroethylene micro powder and vinylidene fluoride-hexafluoropropylene copolymer micro powder.

4. The low-dielectric polyphenylene ether foam material according to claim 1, characterized in that, The mass ratio of the dried polystyrene, 5-fluorobicyclo[2.2.1]heptene, 1-vinyladamantane, di-tert-amyl peroxide, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl)phosphite is 100:1.25:0.8:0.08:0.05:0.

05.

5. The low-dielectric polyphenylene ether foam material according to claim 1, characterized in that, The mass ratio of the dried polymethylpentene, perfluorononenyl succinimide, vinyl norbornene, di-tert-pentyl peroxide, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl) phosphite is 100:1.5:1:0.08:0.05:0.

05.

6. The low-dielectric polyphenylene ether foam material according to claim 1, characterized in that, The preparation of the silane-modified hollow carbon microspheres includes the following steps: C1. Place the hollow carbon microspheres in a vacuum drying oven and dry them to obtain dried hollow carbon microspheres; C2. Anhydrous ethanol, perfluorooctyltriethoxysilane, vinyltrimethoxysilane and hydrochloric acid are mixed and stirred to obtain a modifier; C3. Add the modifier and dried hollow carbon microspheres to the reaction vessel and disperse them by ultrasonication. Heat the reaction vessel to 60°C and stir. Filter, collect the filter cake, wash the filter cake with anhydrous ethanol, and dry the washed filter cake in an oven to obtain silane-modified hollow carbon microspheres.

7. The low-dielectric polyphenylene ether foam material according to claim 6, characterized in that, Hydrochloric acid was added to C2 to adjust the pH to 4-5; The mass ratio of anhydrous ethanol, perfluorooctyltriethoxysilane, and vinyltrimethoxysilane in C2 is 1000:6.5:4; The mass ratio of the modifier to the dried hollow carbon microspheres in C3 is 10:

1.

8. A preparation process for a low-dielectric polyphenylene ether foam material according to any one of claims 1-7, characterized in that, The preparation process of the low-dielectric polyphenylene ether foam material includes the following steps: S1. Place polyphenylene ether, modified polystyrene, and modified polymethylpentene into a vacuum drying oven for drying, and place silane-modified hollow carbon microspheres and nano-silica into another vacuum drying oven for drying. Place the dried polyphenylene ether, modified polystyrene, modified polymethylpentene, silane-modified hollow carbon microspheres, and nano-silica into a reaction vessel, add antioxidants, styrene-ethylene / butene-styrene star-shaped block copolymers, and fluorine processing aids, mix and stir to obtain material D; S2. Material D is fed into a twin-screw extruder and extruded to obtain material E. Material E is granulated and dried to obtain composite foamed granules. S3. Place the composite foamed granules into a foaming machine, inject supercritical CO2, and demold to obtain low-dielectric polyphenylene ether foamed material.

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